3221 lines
82 KiB
C
3221 lines
82 KiB
C
/*-
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* Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
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* Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/*
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* Dynamic linker for ELF.
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*
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* John Polstra <jdp@polstra.com>.
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*/
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#ifndef __GNUC__
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#error "GCC is needed to compile this file"
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#endif
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#include <sys/param.h>
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#include <sys/mount.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <dlfcn.h>
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#include <err.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "debug.h"
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#include "rtld.h"
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#include "libmap.h"
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#include "rtld_tls.h"
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#ifndef COMPAT_32BIT
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#define PATH_RTLD "/libexec/ld-elf.so.1"
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#else
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#define PATH_RTLD "/libexec/ld-elf32.so.1"
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#endif
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/* Types. */
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typedef void (*func_ptr_type)();
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typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
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/*
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* This structure provides a reentrant way to keep a list of objects and
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* check which ones have already been processed in some way.
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*/
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typedef struct Struct_DoneList {
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const Obj_Entry **objs; /* Array of object pointers */
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unsigned int num_alloc; /* Allocated size of the array */
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unsigned int num_used; /* Number of array slots used */
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} DoneList;
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/*
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* Function declarations.
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*/
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static const char *basename(const char *);
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static void die(void) __dead2;
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static void digest_dynamic(Obj_Entry *, int);
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static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
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static Obj_Entry *dlcheck(void *);
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static Obj_Entry *do_load_object(int, const char *, char *, struct stat *);
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static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
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static bool donelist_check(DoneList *, const Obj_Entry *);
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static void errmsg_restore(char *);
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static char *errmsg_save(void);
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static void *fill_search_info(const char *, size_t, void *);
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static char *find_library(const char *, const Obj_Entry *);
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static const char *gethints(void);
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static void init_dag(Obj_Entry *);
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static void init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *);
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static void init_rtld(caddr_t);
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static void initlist_add_neededs(Needed_Entry *needed, Objlist *list);
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static void initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail,
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Objlist *list);
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static bool is_exported(const Elf_Sym *);
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static void linkmap_add(Obj_Entry *);
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static void linkmap_delete(Obj_Entry *);
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static int load_needed_objects(Obj_Entry *);
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static int load_preload_objects(void);
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static Obj_Entry *load_object(const char *, const Obj_Entry *);
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static Obj_Entry *obj_from_addr(const void *);
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static void objlist_call_fini(Objlist *);
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static void objlist_call_init(Objlist *);
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static void objlist_clear(Objlist *);
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static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
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static void objlist_init(Objlist *);
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static void objlist_push_head(Objlist *, Obj_Entry *);
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static void objlist_push_tail(Objlist *, Obj_Entry *);
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static void objlist_remove(Objlist *, Obj_Entry *);
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static void objlist_remove_unref(Objlist *);
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static void *path_enumerate(const char *, path_enum_proc, void *);
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static int relocate_objects(Obj_Entry *, bool, Obj_Entry *);
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static int rtld_dirname(const char *, char *);
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static void rtld_exit(void);
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static char *search_library_path(const char *, const char *);
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static const void **get_program_var_addr(const char *);
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static void set_program_var(const char *, const void *);
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static const Elf_Sym *symlook_default(const char *, unsigned long,
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const Obj_Entry *, const Obj_Entry **, const Ver_Entry *, int);
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static const Elf_Sym *symlook_list(const char *, unsigned long, Objlist *,
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const Obj_Entry **, const Ver_Entry *, int flags, DoneList *);
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static void trace_loaded_objects(Obj_Entry *obj);
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static void unlink_object(Obj_Entry *);
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static void unload_object(Obj_Entry *);
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static void unref_dag(Obj_Entry *);
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static void ref_dag(Obj_Entry *);
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static int rtld_verify_versions(const Objlist *);
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static int rtld_verify_object_versions(Obj_Entry *);
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static void object_add_name(Obj_Entry *, const char *);
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static int object_match_name(const Obj_Entry *, const char *);
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void r_debug_state(struct r_debug*, struct link_map*);
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/*
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* Data declarations.
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*/
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static char *error_message; /* Message for dlerror(), or NULL */
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struct r_debug r_debug; /* for GDB; */
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static bool libmap_disable; /* Disable libmap */
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static char *libmap_override; /* Maps to use in addition to libmap.conf */
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static bool trust; /* False for setuid and setgid programs */
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static bool dangerous_ld_env; /* True if environment variables have been
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used to affect the libraries loaded */
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static char *ld_bind_now; /* Environment variable for immediate binding */
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static char *ld_debug; /* Environment variable for debugging */
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static char *ld_library_path; /* Environment variable for search path */
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static char *ld_preload; /* Environment variable for libraries to
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load first */
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static char *ld_tracing; /* Called from ldd to print libs */
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static Obj_Entry *obj_list; /* Head of linked list of shared objects */
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static Obj_Entry **obj_tail; /* Link field of last object in list */
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static Obj_Entry *obj_main; /* The main program shared object */
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static Obj_Entry obj_rtld; /* The dynamic linker shared object */
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static unsigned int obj_count; /* Number of objects in obj_list */
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static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
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STAILQ_HEAD_INITIALIZER(list_global);
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static Objlist list_main = /* Objects loaded at program startup */
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STAILQ_HEAD_INITIALIZER(list_main);
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static Objlist list_fini = /* Objects needing fini() calls */
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STAILQ_HEAD_INITIALIZER(list_fini);
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static Elf_Sym sym_zero; /* For resolving undefined weak refs. */
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#define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
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extern Elf_Dyn _DYNAMIC;
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#pragma weak _DYNAMIC
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#ifndef RTLD_IS_DYNAMIC
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#define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
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#endif
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/*
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* These are the functions the dynamic linker exports to application
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* programs. They are the only symbols the dynamic linker is willing
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* to export from itself.
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*/
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static func_ptr_type exports[] = {
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(func_ptr_type) &_rtld_error,
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(func_ptr_type) &dlclose,
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(func_ptr_type) &dlerror,
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(func_ptr_type) &dlopen,
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(func_ptr_type) &dlsym,
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(func_ptr_type) &dlvsym,
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(func_ptr_type) &dladdr,
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(func_ptr_type) &dllockinit,
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(func_ptr_type) &dlinfo,
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(func_ptr_type) &_rtld_thread_init,
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#ifdef __i386__
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(func_ptr_type) &___tls_get_addr,
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#endif
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(func_ptr_type) &__tls_get_addr,
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(func_ptr_type) &_rtld_allocate_tls,
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(func_ptr_type) &_rtld_free_tls,
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NULL
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};
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/*
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* Global declarations normally provided by crt1. The dynamic linker is
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* not built with crt1, so we have to provide them ourselves.
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*/
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char *__progname;
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char **environ;
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/*
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* Globals to control TLS allocation.
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*/
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size_t tls_last_offset; /* Static TLS offset of last module */
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size_t tls_last_size; /* Static TLS size of last module */
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size_t tls_static_space; /* Static TLS space allocated */
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int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
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int tls_max_index = 1; /* Largest module index allocated */
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/*
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* Fill in a DoneList with an allocation large enough to hold all of
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* the currently-loaded objects. Keep this as a macro since it calls
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* alloca and we want that to occur within the scope of the caller.
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*/
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#define donelist_init(dlp) \
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((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
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assert((dlp)->objs != NULL), \
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(dlp)->num_alloc = obj_count, \
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(dlp)->num_used = 0)
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/*
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* Main entry point for dynamic linking. The first argument is the
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* stack pointer. The stack is expected to be laid out as described
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* in the SVR4 ABI specification, Intel 386 Processor Supplement.
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* Specifically, the stack pointer points to a word containing
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* ARGC. Following that in the stack is a null-terminated sequence
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* of pointers to argument strings. Then comes a null-terminated
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* sequence of pointers to environment strings. Finally, there is a
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* sequence of "auxiliary vector" entries.
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*
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* The second argument points to a place to store the dynamic linker's
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* exit procedure pointer and the third to a place to store the main
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* program's object.
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*
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* The return value is the main program's entry point.
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*/
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func_ptr_type
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_rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
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{
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Elf_Auxinfo *aux_info[AT_COUNT];
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int i;
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int argc;
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char **argv;
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char **env;
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Elf_Auxinfo *aux;
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Elf_Auxinfo *auxp;
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const char *argv0;
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Objlist_Entry *entry;
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Obj_Entry *obj;
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Obj_Entry **preload_tail;
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Objlist initlist;
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int lockstate;
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/*
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* On entry, the dynamic linker itself has not been relocated yet.
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* Be very careful not to reference any global data until after
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* init_rtld has returned. It is OK to reference file-scope statics
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* and string constants, and to call static and global functions.
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*/
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/* Find the auxiliary vector on the stack. */
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argc = *sp++;
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argv = (char **) sp;
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sp += argc + 1; /* Skip over arguments and NULL terminator */
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env = (char **) sp;
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while (*sp++ != 0) /* Skip over environment, and NULL terminator */
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;
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aux = (Elf_Auxinfo *) sp;
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/* Digest the auxiliary vector. */
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for (i = 0; i < AT_COUNT; i++)
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aux_info[i] = NULL;
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for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
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if (auxp->a_type < AT_COUNT)
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aux_info[auxp->a_type] = auxp;
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}
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/* Initialize and relocate ourselves. */
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assert(aux_info[AT_BASE] != NULL);
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init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
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__progname = obj_rtld.path;
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argv0 = argv[0] != NULL ? argv[0] : "(null)";
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environ = env;
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trust = !issetugid();
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ld_bind_now = getenv(LD_ "BIND_NOW");
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if (trust) {
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ld_debug = getenv(LD_ "DEBUG");
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libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
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libmap_override = getenv(LD_ "LIBMAP");
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ld_library_path = getenv(LD_ "LIBRARY_PATH");
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ld_preload = getenv(LD_ "PRELOAD");
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dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
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(ld_library_path != NULL) || (ld_preload != NULL);
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} else
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dangerous_ld_env = 0;
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ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
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if (ld_debug != NULL && *ld_debug != '\0')
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debug = 1;
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dbg("%s is initialized, base address = %p", __progname,
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(caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
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dbg("RTLD dynamic = %p", obj_rtld.dynamic);
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dbg("RTLD pltgot = %p", obj_rtld.pltgot);
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/*
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* Load the main program, or process its program header if it is
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* already loaded.
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*/
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if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
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int fd = aux_info[AT_EXECFD]->a_un.a_val;
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dbg("loading main program");
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obj_main = map_object(fd, argv0, NULL);
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close(fd);
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if (obj_main == NULL)
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die();
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} else { /* Main program already loaded. */
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const Elf_Phdr *phdr;
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int phnum;
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caddr_t entry;
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dbg("processing main program's program header");
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assert(aux_info[AT_PHDR] != NULL);
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phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
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assert(aux_info[AT_PHNUM] != NULL);
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phnum = aux_info[AT_PHNUM]->a_un.a_val;
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assert(aux_info[AT_PHENT] != NULL);
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assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
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assert(aux_info[AT_ENTRY] != NULL);
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entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
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if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
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die();
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}
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obj_main->path = xstrdup(argv0);
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obj_main->mainprog = true;
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/*
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* Get the actual dynamic linker pathname from the executable if
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* possible. (It should always be possible.) That ensures that
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* gdb will find the right dynamic linker even if a non-standard
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* one is being used.
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*/
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if (obj_main->interp != NULL &&
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strcmp(obj_main->interp, obj_rtld.path) != 0) {
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free(obj_rtld.path);
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obj_rtld.path = xstrdup(obj_main->interp);
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__progname = obj_rtld.path;
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}
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digest_dynamic(obj_main, 0);
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linkmap_add(obj_main);
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linkmap_add(&obj_rtld);
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/* Link the main program into the list of objects. */
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*obj_tail = obj_main;
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obj_tail = &obj_main->next;
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obj_count++;
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/* Make sure we don't call the main program's init and fini functions. */
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obj_main->init = obj_main->fini = (Elf_Addr)NULL;
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/* Initialize a fake symbol for resolving undefined weak references. */
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sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
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sym_zero.st_shndx = SHN_UNDEF;
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if (!libmap_disable)
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libmap_disable = (bool)lm_init(libmap_override);
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dbg("loading LD_PRELOAD libraries");
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if (load_preload_objects() == -1)
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die();
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preload_tail = obj_tail;
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dbg("loading needed objects");
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if (load_needed_objects(obj_main) == -1)
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die();
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/* Make a list of all objects loaded at startup. */
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for (obj = obj_list; obj != NULL; obj = obj->next) {
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objlist_push_tail(&list_main, obj);
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obj->refcount++;
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}
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dbg("checking for required versions");
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if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
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die();
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if (ld_tracing) { /* We're done */
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trace_loaded_objects(obj_main);
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exit(0);
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}
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if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
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dump_relocations(obj_main);
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exit (0);
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}
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/* setup TLS for main thread */
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dbg("initializing initial thread local storage");
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STAILQ_FOREACH(entry, &list_main, link) {
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/*
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* Allocate all the initial objects out of the static TLS
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* block even if they didn't ask for it.
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*/
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allocate_tls_offset(entry->obj);
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}
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allocate_initial_tls(obj_list);
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if (relocate_objects(obj_main,
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ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld) == -1)
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die();
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dbg("doing copy relocations");
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if (do_copy_relocations(obj_main) == -1)
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die();
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if (getenv(LD_ "DUMP_REL_POST") != NULL) {
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dump_relocations(obj_main);
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exit (0);
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}
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dbg("initializing key program variables");
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set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
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set_program_var("environ", env);
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dbg("initializing thread locks");
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lockdflt_init();
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/* Make a list of init functions to call. */
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objlist_init(&initlist);
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initlist_add_objects(obj_list, preload_tail, &initlist);
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r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
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objlist_call_init(&initlist);
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lockstate = wlock_acquire(rtld_bind_lock);
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objlist_clear(&initlist);
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wlock_release(rtld_bind_lock, lockstate);
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dbg("transferring control to program entry point = %p", obj_main->entry);
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/* Return the exit procedure and the program entry point. */
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*exit_proc = rtld_exit;
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*objp = obj_main;
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return (func_ptr_type) obj_main->entry;
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}
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Elf_Addr
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_rtld_bind(Obj_Entry *obj, Elf_Size reloff)
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|
{
|
|
const Elf_Rel *rel;
|
|
const Elf_Sym *def;
|
|
const Obj_Entry *defobj;
|
|
Elf_Addr *where;
|
|
Elf_Addr target;
|
|
int lockstate;
|
|
|
|
lockstate = rlock_acquire(rtld_bind_lock);
|
|
if (obj->pltrel)
|
|
rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
|
|
else
|
|
rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
|
|
|
|
where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
|
|
def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL);
|
|
if (def == NULL)
|
|
die();
|
|
|
|
target = (Elf_Addr)(defobj->relocbase + def->st_value);
|
|
|
|
dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
|
|
defobj->strtab + def->st_name, basename(obj->path),
|
|
(void *)target, basename(defobj->path));
|
|
|
|
/*
|
|
* Write the new contents for the jmpslot. Note that depending on
|
|
* architecture, the value which we need to return back to the
|
|
* lazy binding trampoline may or may not be the target
|
|
* address. The value returned from reloc_jmpslot() is the value
|
|
* that the trampoline needs.
|
|
*/
|
|
target = reloc_jmpslot(where, target, defobj, obj, rel);
|
|
rlock_release(rtld_bind_lock, lockstate);
|
|
return target;
|
|
}
|
|
|
|
/*
|
|
* Error reporting function. Use it like printf. If formats the message
|
|
* into a buffer, and sets things up so that the next call to dlerror()
|
|
* will return the message.
|
|
*/
|
|
void
|
|
_rtld_error(const char *fmt, ...)
|
|
{
|
|
static char buf[512];
|
|
va_list ap;
|
|
|
|
va_start(ap, fmt);
|
|
vsnprintf(buf, sizeof buf, fmt, ap);
|
|
error_message = buf;
|
|
va_end(ap);
|
|
}
|
|
|
|
/*
|
|
* Return a dynamically-allocated copy of the current error message, if any.
|
|
*/
|
|
static char *
|
|
errmsg_save(void)
|
|
{
|
|
return error_message == NULL ? NULL : xstrdup(error_message);
|
|
}
|
|
|
|
/*
|
|
* Restore the current error message from a copy which was previously saved
|
|
* by errmsg_save(). The copy is freed.
|
|
*/
|
|
static void
|
|
errmsg_restore(char *saved_msg)
|
|
{
|
|
if (saved_msg == NULL)
|
|
error_message = NULL;
|
|
else {
|
|
_rtld_error("%s", saved_msg);
|
|
free(saved_msg);
|
|
}
|
|
}
|
|
|
|
static const char *
|
|
basename(const char *name)
|
|
{
|
|
const char *p = strrchr(name, '/');
|
|
return p != NULL ? p + 1 : name;
|
|
}
|
|
|
|
static void
|
|
die(void)
|
|
{
|
|
const char *msg = dlerror();
|
|
|
|
if (msg == NULL)
|
|
msg = "Fatal error";
|
|
errx(1, "%s", msg);
|
|
}
|
|
|
|
/*
|
|
* Process a shared object's DYNAMIC section, and save the important
|
|
* information in its Obj_Entry structure.
|
|
*/
|
|
static void
|
|
digest_dynamic(Obj_Entry *obj, int early)
|
|
{
|
|
const Elf_Dyn *dynp;
|
|
Needed_Entry **needed_tail = &obj->needed;
|
|
const Elf_Dyn *dyn_rpath = NULL;
|
|
const Elf_Dyn *dyn_soname = NULL;
|
|
int plttype = DT_REL;
|
|
|
|
obj->bind_now = false;
|
|
for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
|
|
switch (dynp->d_tag) {
|
|
|
|
case DT_REL:
|
|
obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
|
|
break;
|
|
|
|
case DT_RELSZ:
|
|
obj->relsize = dynp->d_un.d_val;
|
|
break;
|
|
|
|
case DT_RELENT:
|
|
assert(dynp->d_un.d_val == sizeof(Elf_Rel));
|
|
break;
|
|
|
|
case DT_JMPREL:
|
|
obj->pltrel = (const Elf_Rel *)
|
|
(obj->relocbase + dynp->d_un.d_ptr);
|
|
break;
|
|
|
|
case DT_PLTRELSZ:
|
|
obj->pltrelsize = dynp->d_un.d_val;
|
|
break;
|
|
|
|
case DT_RELA:
|
|
obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
|
|
break;
|
|
|
|
case DT_RELASZ:
|
|
obj->relasize = dynp->d_un.d_val;
|
|
break;
|
|
|
|
case DT_RELAENT:
|
|
assert(dynp->d_un.d_val == sizeof(Elf_Rela));
|
|
break;
|
|
|
|
case DT_PLTREL:
|
|
plttype = dynp->d_un.d_val;
|
|
assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
|
|
break;
|
|
|
|
case DT_SYMTAB:
|
|
obj->symtab = (const Elf_Sym *)
|
|
(obj->relocbase + dynp->d_un.d_ptr);
|
|
break;
|
|
|
|
case DT_SYMENT:
|
|
assert(dynp->d_un.d_val == sizeof(Elf_Sym));
|
|
break;
|
|
|
|
case DT_STRTAB:
|
|
obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
|
|
break;
|
|
|
|
case DT_STRSZ:
|
|
obj->strsize = dynp->d_un.d_val;
|
|
break;
|
|
|
|
case DT_VERNEED:
|
|
obj->verneed = (const Elf_Verneed *) (obj->relocbase +
|
|
dynp->d_un.d_val);
|
|
break;
|
|
|
|
case DT_VERNEEDNUM:
|
|
obj->verneednum = dynp->d_un.d_val;
|
|
break;
|
|
|
|
case DT_VERDEF:
|
|
obj->verdef = (const Elf_Verdef *) (obj->relocbase +
|
|
dynp->d_un.d_val);
|
|
break;
|
|
|
|
case DT_VERDEFNUM:
|
|
obj->verdefnum = dynp->d_un.d_val;
|
|
break;
|
|
|
|
case DT_VERSYM:
|
|
obj->versyms = (const Elf_Versym *)(obj->relocbase +
|
|
dynp->d_un.d_val);
|
|
break;
|
|
|
|
case DT_HASH:
|
|
{
|
|
const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
|
|
(obj->relocbase + dynp->d_un.d_ptr);
|
|
obj->nbuckets = hashtab[0];
|
|
obj->nchains = hashtab[1];
|
|
obj->buckets = hashtab + 2;
|
|
obj->chains = obj->buckets + obj->nbuckets;
|
|
}
|
|
break;
|
|
|
|
case DT_NEEDED:
|
|
if (!obj->rtld) {
|
|
Needed_Entry *nep = NEW(Needed_Entry);
|
|
nep->name = dynp->d_un.d_val;
|
|
nep->obj = NULL;
|
|
nep->next = NULL;
|
|
|
|
*needed_tail = nep;
|
|
needed_tail = &nep->next;
|
|
}
|
|
break;
|
|
|
|
case DT_PLTGOT:
|
|
obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
|
|
break;
|
|
|
|
case DT_TEXTREL:
|
|
obj->textrel = true;
|
|
break;
|
|
|
|
case DT_SYMBOLIC:
|
|
obj->symbolic = true;
|
|
break;
|
|
|
|
case DT_RPATH:
|
|
case DT_RUNPATH: /* XXX: process separately */
|
|
/*
|
|
* We have to wait until later to process this, because we
|
|
* might not have gotten the address of the string table yet.
|
|
*/
|
|
dyn_rpath = dynp;
|
|
break;
|
|
|
|
case DT_SONAME:
|
|
dyn_soname = dynp;
|
|
break;
|
|
|
|
case DT_INIT:
|
|
obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
|
|
break;
|
|
|
|
case DT_FINI:
|
|
obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
|
|
break;
|
|
|
|
case DT_DEBUG:
|
|
/* XXX - not implemented yet */
|
|
if (!early)
|
|
dbg("Filling in DT_DEBUG entry");
|
|
((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
|
|
break;
|
|
|
|
case DT_FLAGS:
|
|
if (dynp->d_un.d_val & DF_ORIGIN) {
|
|
obj->origin_path = xmalloc(PATH_MAX);
|
|
if (rtld_dirname(obj->path, obj->origin_path) == -1)
|
|
die();
|
|
}
|
|
if (dynp->d_un.d_val & DF_SYMBOLIC)
|
|
obj->symbolic = true;
|
|
if (dynp->d_un.d_val & DF_TEXTREL)
|
|
obj->textrel = true;
|
|
if (dynp->d_un.d_val & DF_BIND_NOW)
|
|
obj->bind_now = true;
|
|
if (dynp->d_un.d_val & DF_STATIC_TLS)
|
|
;
|
|
break;
|
|
|
|
default:
|
|
if (!early) {
|
|
dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
|
|
(long)dynp->d_tag);
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
obj->traced = false;
|
|
|
|
if (plttype == DT_RELA) {
|
|
obj->pltrela = (const Elf_Rela *) obj->pltrel;
|
|
obj->pltrel = NULL;
|
|
obj->pltrelasize = obj->pltrelsize;
|
|
obj->pltrelsize = 0;
|
|
}
|
|
|
|
if (dyn_rpath != NULL)
|
|
obj->rpath = obj->strtab + dyn_rpath->d_un.d_val;
|
|
|
|
if (dyn_soname != NULL)
|
|
object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
|
|
}
|
|
|
|
/*
|
|
* Process a shared object's program header. This is used only for the
|
|
* main program, when the kernel has already loaded the main program
|
|
* into memory before calling the dynamic linker. It creates and
|
|
* returns an Obj_Entry structure.
|
|
*/
|
|
static Obj_Entry *
|
|
digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
|
|
{
|
|
Obj_Entry *obj;
|
|
const Elf_Phdr *phlimit = phdr + phnum;
|
|
const Elf_Phdr *ph;
|
|
int nsegs = 0;
|
|
|
|
obj = obj_new();
|
|
for (ph = phdr; ph < phlimit; ph++) {
|
|
switch (ph->p_type) {
|
|
|
|
case PT_PHDR:
|
|
if ((const Elf_Phdr *)ph->p_vaddr != phdr) {
|
|
_rtld_error("%s: invalid PT_PHDR", path);
|
|
return NULL;
|
|
}
|
|
obj->phdr = (const Elf_Phdr *) ph->p_vaddr;
|
|
obj->phsize = ph->p_memsz;
|
|
break;
|
|
|
|
case PT_INTERP:
|
|
obj->interp = (const char *) ph->p_vaddr;
|
|
break;
|
|
|
|
case PT_LOAD:
|
|
if (nsegs == 0) { /* First load segment */
|
|
obj->vaddrbase = trunc_page(ph->p_vaddr);
|
|
obj->mapbase = (caddr_t) obj->vaddrbase;
|
|
obj->relocbase = obj->mapbase - obj->vaddrbase;
|
|
obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
|
|
obj->vaddrbase;
|
|
} else { /* Last load segment */
|
|
obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
|
|
obj->vaddrbase;
|
|
}
|
|
nsegs++;
|
|
break;
|
|
|
|
case PT_DYNAMIC:
|
|
obj->dynamic = (const Elf_Dyn *) ph->p_vaddr;
|
|
break;
|
|
|
|
case PT_TLS:
|
|
obj->tlsindex = 1;
|
|
obj->tlssize = ph->p_memsz;
|
|
obj->tlsalign = ph->p_align;
|
|
obj->tlsinitsize = ph->p_filesz;
|
|
obj->tlsinit = (void*) ph->p_vaddr;
|
|
break;
|
|
}
|
|
}
|
|
if (nsegs < 1) {
|
|
_rtld_error("%s: too few PT_LOAD segments", path);
|
|
return NULL;
|
|
}
|
|
|
|
obj->entry = entry;
|
|
return obj;
|
|
}
|
|
|
|
static Obj_Entry *
|
|
dlcheck(void *handle)
|
|
{
|
|
Obj_Entry *obj;
|
|
|
|
for (obj = obj_list; obj != NULL; obj = obj->next)
|
|
if (obj == (Obj_Entry *) handle)
|
|
break;
|
|
|
|
if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
|
|
_rtld_error("Invalid shared object handle %p", handle);
|
|
return NULL;
|
|
}
|
|
return obj;
|
|
}
|
|
|
|
/*
|
|
* If the given object is already in the donelist, return true. Otherwise
|
|
* add the object to the list and return false.
|
|
*/
|
|
static bool
|
|
donelist_check(DoneList *dlp, const Obj_Entry *obj)
|
|
{
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < dlp->num_used; i++)
|
|
if (dlp->objs[i] == obj)
|
|
return true;
|
|
/*
|
|
* Our donelist allocation should always be sufficient. But if
|
|
* our threads locking isn't working properly, more shared objects
|
|
* could have been loaded since we allocated the list. That should
|
|
* never happen, but we'll handle it properly just in case it does.
|
|
*/
|
|
if (dlp->num_used < dlp->num_alloc)
|
|
dlp->objs[dlp->num_used++] = obj;
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* Hash function for symbol table lookup. Don't even think about changing
|
|
* this. It is specified by the System V ABI.
|
|
*/
|
|
unsigned long
|
|
elf_hash(const char *name)
|
|
{
|
|
const unsigned char *p = (const unsigned char *) name;
|
|
unsigned long h = 0;
|
|
unsigned long g;
|
|
|
|
while (*p != '\0') {
|
|
h = (h << 4) + *p++;
|
|
if ((g = h & 0xf0000000) != 0)
|
|
h ^= g >> 24;
|
|
h &= ~g;
|
|
}
|
|
return h;
|
|
}
|
|
|
|
/*
|
|
* Find the library with the given name, and return its full pathname.
|
|
* The returned string is dynamically allocated. Generates an error
|
|
* message and returns NULL if the library cannot be found.
|
|
*
|
|
* If the second argument is non-NULL, then it refers to an already-
|
|
* loaded shared object, whose library search path will be searched.
|
|
*
|
|
* The search order is:
|
|
* LD_LIBRARY_PATH
|
|
* rpath in the referencing file
|
|
* ldconfig hints
|
|
* /lib:/usr/lib
|
|
*/
|
|
static char *
|
|
find_library(const char *xname, const Obj_Entry *refobj)
|
|
{
|
|
char *pathname;
|
|
char *name;
|
|
|
|
if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
|
|
if (xname[0] != '/' && !trust) {
|
|
_rtld_error("Absolute pathname required for shared object \"%s\"",
|
|
xname);
|
|
return NULL;
|
|
}
|
|
return xstrdup(xname);
|
|
}
|
|
|
|
if (libmap_disable || (refobj == NULL) ||
|
|
(name = lm_find(refobj->path, xname)) == NULL)
|
|
name = (char *)xname;
|
|
|
|
dbg(" Searching for \"%s\"", name);
|
|
|
|
if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
|
|
(refobj != NULL &&
|
|
(pathname = search_library_path(name, refobj->rpath)) != NULL) ||
|
|
(pathname = search_library_path(name, gethints())) != NULL ||
|
|
(pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
|
|
return pathname;
|
|
|
|
if(refobj != NULL && refobj->path != NULL) {
|
|
_rtld_error("Shared object \"%s\" not found, required by \"%s\"",
|
|
name, basename(refobj->path));
|
|
} else {
|
|
_rtld_error("Shared object \"%s\" not found", name);
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Given a symbol number in a referencing object, find the corresponding
|
|
* definition of the symbol. Returns a pointer to the symbol, or NULL if
|
|
* no definition was found. Returns a pointer to the Obj_Entry of the
|
|
* defining object via the reference parameter DEFOBJ_OUT.
|
|
*/
|
|
const Elf_Sym *
|
|
find_symdef(unsigned long symnum, const Obj_Entry *refobj,
|
|
const Obj_Entry **defobj_out, int flags, SymCache *cache)
|
|
{
|
|
const Elf_Sym *ref;
|
|
const Elf_Sym *def;
|
|
const Obj_Entry *defobj;
|
|
const Ver_Entry *ventry;
|
|
const char *name;
|
|
unsigned long hash;
|
|
|
|
/*
|
|
* If we have already found this symbol, get the information from
|
|
* the cache.
|
|
*/
|
|
if (symnum >= refobj->nchains)
|
|
return NULL; /* Bad object */
|
|
if (cache != NULL && cache[symnum].sym != NULL) {
|
|
*defobj_out = cache[symnum].obj;
|
|
return cache[symnum].sym;
|
|
}
|
|
|
|
ref = refobj->symtab + symnum;
|
|
name = refobj->strtab + ref->st_name;
|
|
defobj = NULL;
|
|
|
|
/*
|
|
* We don't have to do a full scale lookup if the symbol is local.
|
|
* We know it will bind to the instance in this load module; to
|
|
* which we already have a pointer (ie ref). By not doing a lookup,
|
|
* we not only improve performance, but it also avoids unresolvable
|
|
* symbols when local symbols are not in the hash table. This has
|
|
* been seen with the ia64 toolchain.
|
|
*/
|
|
if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
|
|
if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
|
|
_rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
|
|
symnum);
|
|
}
|
|
ventry = fetch_ventry(refobj, symnum);
|
|
hash = elf_hash(name);
|
|
def = symlook_default(name, hash, refobj, &defobj, ventry, flags);
|
|
} else {
|
|
def = ref;
|
|
defobj = refobj;
|
|
}
|
|
|
|
/*
|
|
* If we found no definition and the reference is weak, treat the
|
|
* symbol as having the value zero.
|
|
*/
|
|
if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
|
|
def = &sym_zero;
|
|
defobj = obj_main;
|
|
}
|
|
|
|
if (def != NULL) {
|
|
*defobj_out = defobj;
|
|
/* Record the information in the cache to avoid subsequent lookups. */
|
|
if (cache != NULL) {
|
|
cache[symnum].sym = def;
|
|
cache[symnum].obj = defobj;
|
|
}
|
|
} else {
|
|
if (refobj != &obj_rtld)
|
|
_rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
|
|
}
|
|
return def;
|
|
}
|
|
|
|
/*
|
|
* Return the search path from the ldconfig hints file, reading it if
|
|
* necessary. Returns NULL if there are problems with the hints file,
|
|
* or if the search path there is empty.
|
|
*/
|
|
static const char *
|
|
gethints(void)
|
|
{
|
|
static char *hints;
|
|
|
|
if (hints == NULL) {
|
|
int fd;
|
|
struct elfhints_hdr hdr;
|
|
char *p;
|
|
|
|
/* Keep from trying again in case the hints file is bad. */
|
|
hints = "";
|
|
|
|
if ((fd = open(_PATH_ELF_HINTS, O_RDONLY)) == -1)
|
|
return NULL;
|
|
if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
|
|
hdr.magic != ELFHINTS_MAGIC ||
|
|
hdr.version != 1) {
|
|
close(fd);
|
|
return NULL;
|
|
}
|
|
p = xmalloc(hdr.dirlistlen + 1);
|
|
if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
|
|
read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) {
|
|
free(p);
|
|
close(fd);
|
|
return NULL;
|
|
}
|
|
hints = p;
|
|
close(fd);
|
|
}
|
|
return hints[0] != '\0' ? hints : NULL;
|
|
}
|
|
|
|
static void
|
|
init_dag(Obj_Entry *root)
|
|
{
|
|
DoneList donelist;
|
|
|
|
donelist_init(&donelist);
|
|
init_dag1(root, root, &donelist);
|
|
}
|
|
|
|
static void
|
|
init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp)
|
|
{
|
|
const Needed_Entry *needed;
|
|
|
|
if (donelist_check(dlp, obj))
|
|
return;
|
|
|
|
obj->refcount++;
|
|
objlist_push_tail(&obj->dldags, root);
|
|
objlist_push_tail(&root->dagmembers, obj);
|
|
for (needed = obj->needed; needed != NULL; needed = needed->next)
|
|
if (needed->obj != NULL)
|
|
init_dag1(root, needed->obj, dlp);
|
|
}
|
|
|
|
/*
|
|
* Initialize the dynamic linker. The argument is the address at which
|
|
* the dynamic linker has been mapped into memory. The primary task of
|
|
* this function is to relocate the dynamic linker.
|
|
*/
|
|
static void
|
|
init_rtld(caddr_t mapbase)
|
|
{
|
|
Obj_Entry objtmp; /* Temporary rtld object */
|
|
|
|
/*
|
|
* Conjure up an Obj_Entry structure for the dynamic linker.
|
|
*
|
|
* The "path" member can't be initialized yet because string constatns
|
|
* cannot yet be acessed. Below we will set it correctly.
|
|
*/
|
|
memset(&objtmp, 0, sizeof(objtmp));
|
|
objtmp.path = NULL;
|
|
objtmp.rtld = true;
|
|
objtmp.mapbase = mapbase;
|
|
#ifdef PIC
|
|
objtmp.relocbase = mapbase;
|
|
#endif
|
|
if (RTLD_IS_DYNAMIC()) {
|
|
objtmp.dynamic = rtld_dynamic(&objtmp);
|
|
digest_dynamic(&objtmp, 1);
|
|
assert(objtmp.needed == NULL);
|
|
assert(!objtmp.textrel);
|
|
|
|
/*
|
|
* Temporarily put the dynamic linker entry into the object list, so
|
|
* that symbols can be found.
|
|
*/
|
|
|
|
relocate_objects(&objtmp, true, &objtmp);
|
|
}
|
|
|
|
/* Initialize the object list. */
|
|
obj_tail = &obj_list;
|
|
|
|
/* Now that non-local variables can be accesses, copy out obj_rtld. */
|
|
memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
|
|
|
|
/* Replace the path with a dynamically allocated copy. */
|
|
obj_rtld.path = xstrdup(PATH_RTLD);
|
|
|
|
r_debug.r_brk = r_debug_state;
|
|
r_debug.r_state = RT_CONSISTENT;
|
|
}
|
|
|
|
/*
|
|
* Add the init functions from a needed object list (and its recursive
|
|
* needed objects) to "list". This is not used directly; it is a helper
|
|
* function for initlist_add_objects(). The write lock must be held
|
|
* when this function is called.
|
|
*/
|
|
static void
|
|
initlist_add_neededs(Needed_Entry *needed, Objlist *list)
|
|
{
|
|
/* Recursively process the successor needed objects. */
|
|
if (needed->next != NULL)
|
|
initlist_add_neededs(needed->next, list);
|
|
|
|
/* Process the current needed object. */
|
|
if (needed->obj != NULL)
|
|
initlist_add_objects(needed->obj, &needed->obj->next, list);
|
|
}
|
|
|
|
/*
|
|
* Scan all of the DAGs rooted in the range of objects from "obj" to
|
|
* "tail" and add their init functions to "list". This recurses over
|
|
* the DAGs and ensure the proper init ordering such that each object's
|
|
* needed libraries are initialized before the object itself. At the
|
|
* same time, this function adds the objects to the global finalization
|
|
* list "list_fini" in the opposite order. The write lock must be
|
|
* held when this function is called.
|
|
*/
|
|
static void
|
|
initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
|
|
{
|
|
if (obj->init_done)
|
|
return;
|
|
obj->init_done = true;
|
|
|
|
/* Recursively process the successor objects. */
|
|
if (&obj->next != tail)
|
|
initlist_add_objects(obj->next, tail, list);
|
|
|
|
/* Recursively process the needed objects. */
|
|
if (obj->needed != NULL)
|
|
initlist_add_neededs(obj->needed, list);
|
|
|
|
/* Add the object to the init list. */
|
|
if (obj->init != (Elf_Addr)NULL)
|
|
objlist_push_tail(list, obj);
|
|
|
|
/* Add the object to the global fini list in the reverse order. */
|
|
if (obj->fini != (Elf_Addr)NULL)
|
|
objlist_push_head(&list_fini, obj);
|
|
}
|
|
|
|
#ifndef FPTR_TARGET
|
|
#define FPTR_TARGET(f) ((Elf_Addr) (f))
|
|
#endif
|
|
|
|
static bool
|
|
is_exported(const Elf_Sym *def)
|
|
{
|
|
Elf_Addr value;
|
|
const func_ptr_type *p;
|
|
|
|
value = (Elf_Addr)(obj_rtld.relocbase + def->st_value);
|
|
for (p = exports; *p != NULL; p++)
|
|
if (FPTR_TARGET(*p) == value)
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* Given a shared object, traverse its list of needed objects, and load
|
|
* each of them. Returns 0 on success. Generates an error message and
|
|
* returns -1 on failure.
|
|
*/
|
|
static int
|
|
load_needed_objects(Obj_Entry *first)
|
|
{
|
|
Obj_Entry *obj;
|
|
|
|
for (obj = first; obj != NULL; obj = obj->next) {
|
|
Needed_Entry *needed;
|
|
|
|
for (needed = obj->needed; needed != NULL; needed = needed->next) {
|
|
needed->obj = load_object(obj->strtab + needed->name, obj);
|
|
if (needed->obj == NULL && !ld_tracing)
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
load_preload_objects(void)
|
|
{
|
|
char *p = ld_preload;
|
|
static const char delim[] = " \t:;";
|
|
|
|
if (p == NULL)
|
|
return 0;
|
|
|
|
p += strspn(p, delim);
|
|
while (*p != '\0') {
|
|
size_t len = strcspn(p, delim);
|
|
char savech;
|
|
|
|
savech = p[len];
|
|
p[len] = '\0';
|
|
if (load_object(p, NULL) == NULL)
|
|
return -1; /* XXX - cleanup */
|
|
p[len] = savech;
|
|
p += len;
|
|
p += strspn(p, delim);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Load a shared object into memory, if it is not already loaded.
|
|
*
|
|
* Returns a pointer to the Obj_Entry for the object. Returns NULL
|
|
* on failure.
|
|
*/
|
|
static Obj_Entry *
|
|
load_object(const char *name, const Obj_Entry *refobj)
|
|
{
|
|
Obj_Entry *obj;
|
|
int fd = -1;
|
|
struct stat sb;
|
|
char *path;
|
|
|
|
for (obj = obj_list->next; obj != NULL; obj = obj->next)
|
|
if (object_match_name(obj, name))
|
|
return obj;
|
|
|
|
path = find_library(name, refobj);
|
|
if (path == NULL)
|
|
return NULL;
|
|
|
|
/*
|
|
* If we didn't find a match by pathname, open the file and check
|
|
* again by device and inode. This avoids false mismatches caused
|
|
* by multiple links or ".." in pathnames.
|
|
*
|
|
* To avoid a race, we open the file and use fstat() rather than
|
|
* using stat().
|
|
*/
|
|
if ((fd = open(path, O_RDONLY)) == -1) {
|
|
_rtld_error("Cannot open \"%s\"", path);
|
|
free(path);
|
|
return NULL;
|
|
}
|
|
if (fstat(fd, &sb) == -1) {
|
|
_rtld_error("Cannot fstat \"%s\"", path);
|
|
close(fd);
|
|
free(path);
|
|
return NULL;
|
|
}
|
|
for (obj = obj_list->next; obj != NULL; obj = obj->next) {
|
|
if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) {
|
|
close(fd);
|
|
break;
|
|
}
|
|
}
|
|
if (obj != NULL) {
|
|
object_add_name(obj, name);
|
|
free(path);
|
|
close(fd);
|
|
return obj;
|
|
}
|
|
|
|
/* First use of this object, so we must map it in */
|
|
obj = do_load_object(fd, name, path, &sb);
|
|
if (obj == NULL)
|
|
free(path);
|
|
close(fd);
|
|
|
|
return obj;
|
|
}
|
|
|
|
static Obj_Entry *
|
|
do_load_object(int fd, const char *name, char *path, struct stat *sbp)
|
|
{
|
|
Obj_Entry *obj;
|
|
struct statfs fs;
|
|
|
|
/*
|
|
* but first, make sure that environment variables haven't been
|
|
* used to circumvent the noexec flag on a filesystem.
|
|
*/
|
|
if (dangerous_ld_env) {
|
|
if (fstatfs(fd, &fs) != 0) {
|
|
_rtld_error("Cannot fstatfs \"%s\"", path);
|
|
return NULL;
|
|
}
|
|
if (fs.f_flags & MNT_NOEXEC) {
|
|
_rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
|
|
return NULL;
|
|
}
|
|
}
|
|
dbg("loading \"%s\"", path);
|
|
obj = map_object(fd, path, sbp);
|
|
if (obj == NULL)
|
|
return NULL;
|
|
|
|
object_add_name(obj, name);
|
|
obj->path = path;
|
|
digest_dynamic(obj, 0);
|
|
|
|
*obj_tail = obj;
|
|
obj_tail = &obj->next;
|
|
obj_count++;
|
|
linkmap_add(obj); /* for GDB & dlinfo() */
|
|
|
|
dbg(" %p .. %p: %s", obj->mapbase,
|
|
obj->mapbase + obj->mapsize - 1, obj->path);
|
|
if (obj->textrel)
|
|
dbg(" WARNING: %s has impure text", obj->path);
|
|
|
|
return obj;
|
|
}
|
|
|
|
static Obj_Entry *
|
|
obj_from_addr(const void *addr)
|
|
{
|
|
Obj_Entry *obj;
|
|
|
|
for (obj = obj_list; obj != NULL; obj = obj->next) {
|
|
if (addr < (void *) obj->mapbase)
|
|
continue;
|
|
if (addr < (void *) (obj->mapbase + obj->mapsize))
|
|
return obj;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Call the finalization functions for each of the objects in "list"
|
|
* which are unreferenced. All of the objects are expected to have
|
|
* non-NULL fini functions.
|
|
*/
|
|
static void
|
|
objlist_call_fini(Objlist *list)
|
|
{
|
|
Objlist_Entry *elm;
|
|
char *saved_msg;
|
|
|
|
/*
|
|
* Preserve the current error message since a fini function might
|
|
* call into the dynamic linker and overwrite it.
|
|
*/
|
|
saved_msg = errmsg_save();
|
|
STAILQ_FOREACH(elm, list, link) {
|
|
if (elm->obj->refcount == 0) {
|
|
dbg("calling fini function for %s at %p", elm->obj->path,
|
|
(void *)elm->obj->fini);
|
|
call_initfini_pointer(elm->obj, elm->obj->fini);
|
|
}
|
|
}
|
|
errmsg_restore(saved_msg);
|
|
}
|
|
|
|
/*
|
|
* Call the initialization functions for each of the objects in
|
|
* "list". All of the objects are expected to have non-NULL init
|
|
* functions.
|
|
*/
|
|
static void
|
|
objlist_call_init(Objlist *list)
|
|
{
|
|
Objlist_Entry *elm;
|
|
char *saved_msg;
|
|
|
|
/*
|
|
* Preserve the current error message since an init function might
|
|
* call into the dynamic linker and overwrite it.
|
|
*/
|
|
saved_msg = errmsg_save();
|
|
STAILQ_FOREACH(elm, list, link) {
|
|
dbg("calling init function for %s at %p", elm->obj->path,
|
|
(void *)elm->obj->init);
|
|
call_initfini_pointer(elm->obj, elm->obj->init);
|
|
}
|
|
errmsg_restore(saved_msg);
|
|
}
|
|
|
|
static void
|
|
objlist_clear(Objlist *list)
|
|
{
|
|
Objlist_Entry *elm;
|
|
|
|
while (!STAILQ_EMPTY(list)) {
|
|
elm = STAILQ_FIRST(list);
|
|
STAILQ_REMOVE_HEAD(list, link);
|
|
free(elm);
|
|
}
|
|
}
|
|
|
|
static Objlist_Entry *
|
|
objlist_find(Objlist *list, const Obj_Entry *obj)
|
|
{
|
|
Objlist_Entry *elm;
|
|
|
|
STAILQ_FOREACH(elm, list, link)
|
|
if (elm->obj == obj)
|
|
return elm;
|
|
return NULL;
|
|
}
|
|
|
|
static void
|
|
objlist_init(Objlist *list)
|
|
{
|
|
STAILQ_INIT(list);
|
|
}
|
|
|
|
static void
|
|
objlist_push_head(Objlist *list, Obj_Entry *obj)
|
|
{
|
|
Objlist_Entry *elm;
|
|
|
|
elm = NEW(Objlist_Entry);
|
|
elm->obj = obj;
|
|
STAILQ_INSERT_HEAD(list, elm, link);
|
|
}
|
|
|
|
static void
|
|
objlist_push_tail(Objlist *list, Obj_Entry *obj)
|
|
{
|
|
Objlist_Entry *elm;
|
|
|
|
elm = NEW(Objlist_Entry);
|
|
elm->obj = obj;
|
|
STAILQ_INSERT_TAIL(list, elm, link);
|
|
}
|
|
|
|
static void
|
|
objlist_remove(Objlist *list, Obj_Entry *obj)
|
|
{
|
|
Objlist_Entry *elm;
|
|
|
|
if ((elm = objlist_find(list, obj)) != NULL) {
|
|
STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
|
|
free(elm);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Remove all of the unreferenced objects from "list".
|
|
*/
|
|
static void
|
|
objlist_remove_unref(Objlist *list)
|
|
{
|
|
Objlist newlist;
|
|
Objlist_Entry *elm;
|
|
|
|
STAILQ_INIT(&newlist);
|
|
while (!STAILQ_EMPTY(list)) {
|
|
elm = STAILQ_FIRST(list);
|
|
STAILQ_REMOVE_HEAD(list, link);
|
|
if (elm->obj->refcount == 0)
|
|
free(elm);
|
|
else
|
|
STAILQ_INSERT_TAIL(&newlist, elm, link);
|
|
}
|
|
*list = newlist;
|
|
}
|
|
|
|
/*
|
|
* Relocate newly-loaded shared objects. The argument is a pointer to
|
|
* the Obj_Entry for the first such object. All objects from the first
|
|
* to the end of the list of objects are relocated. Returns 0 on success,
|
|
* or -1 on failure.
|
|
*/
|
|
static int
|
|
relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj)
|
|
{
|
|
Obj_Entry *obj;
|
|
|
|
for (obj = first; obj != NULL; obj = obj->next) {
|
|
if (obj != rtldobj)
|
|
dbg("relocating \"%s\"", obj->path);
|
|
if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL ||
|
|
obj->symtab == NULL || obj->strtab == NULL) {
|
|
_rtld_error("%s: Shared object has no run-time symbol table",
|
|
obj->path);
|
|
return -1;
|
|
}
|
|
|
|
if (obj->textrel) {
|
|
/* There are relocations to the write-protected text segment. */
|
|
if (mprotect(obj->mapbase, obj->textsize,
|
|
PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
|
|
_rtld_error("%s: Cannot write-enable text segment: %s",
|
|
obj->path, strerror(errno));
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
/* Process the non-PLT relocations. */
|
|
if (reloc_non_plt(obj, rtldobj))
|
|
return -1;
|
|
|
|
if (obj->textrel) { /* Re-protected the text segment. */
|
|
if (mprotect(obj->mapbase, obj->textsize,
|
|
PROT_READ|PROT_EXEC) == -1) {
|
|
_rtld_error("%s: Cannot write-protect text segment: %s",
|
|
obj->path, strerror(errno));
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
/* Process the PLT relocations. */
|
|
if (reloc_plt(obj) == -1)
|
|
return -1;
|
|
/* Relocate the jump slots if we are doing immediate binding. */
|
|
if (obj->bind_now || bind_now)
|
|
if (reloc_jmpslots(obj) == -1)
|
|
return -1;
|
|
|
|
|
|
/*
|
|
* Set up the magic number and version in the Obj_Entry. These
|
|
* were checked in the crt1.o from the original ElfKit, so we
|
|
* set them for backward compatibility.
|
|
*/
|
|
obj->magic = RTLD_MAGIC;
|
|
obj->version = RTLD_VERSION;
|
|
|
|
/* Set the special PLT or GOT entries. */
|
|
init_pltgot(obj);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Cleanup procedure. It will be called (by the atexit mechanism) just
|
|
* before the process exits.
|
|
*/
|
|
static void
|
|
rtld_exit(void)
|
|
{
|
|
Obj_Entry *obj;
|
|
|
|
dbg("rtld_exit()");
|
|
/* Clear all the reference counts so the fini functions will be called. */
|
|
for (obj = obj_list; obj != NULL; obj = obj->next)
|
|
obj->refcount = 0;
|
|
objlist_call_fini(&list_fini);
|
|
/* No need to remove the items from the list, since we are exiting. */
|
|
if (!libmap_disable)
|
|
lm_fini();
|
|
}
|
|
|
|
static void *
|
|
path_enumerate(const char *path, path_enum_proc callback, void *arg)
|
|
{
|
|
#ifdef COMPAT_32BIT
|
|
const char *trans;
|
|
#endif
|
|
if (path == NULL)
|
|
return (NULL);
|
|
|
|
path += strspn(path, ":;");
|
|
while (*path != '\0') {
|
|
size_t len;
|
|
char *res;
|
|
|
|
len = strcspn(path, ":;");
|
|
#ifdef COMPAT_32BIT
|
|
trans = lm_findn(NULL, path, len);
|
|
if (trans)
|
|
res = callback(trans, strlen(trans), arg);
|
|
else
|
|
#endif
|
|
res = callback(path, len, arg);
|
|
|
|
if (res != NULL)
|
|
return (res);
|
|
|
|
path += len;
|
|
path += strspn(path, ":;");
|
|
}
|
|
|
|
return (NULL);
|
|
}
|
|
|
|
struct try_library_args {
|
|
const char *name;
|
|
size_t namelen;
|
|
char *buffer;
|
|
size_t buflen;
|
|
};
|
|
|
|
static void *
|
|
try_library_path(const char *dir, size_t dirlen, void *param)
|
|
{
|
|
struct try_library_args *arg;
|
|
|
|
arg = param;
|
|
if (*dir == '/' || trust) {
|
|
char *pathname;
|
|
|
|
if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
|
|
return (NULL);
|
|
|
|
pathname = arg->buffer;
|
|
strncpy(pathname, dir, dirlen);
|
|
pathname[dirlen] = '/';
|
|
strcpy(pathname + dirlen + 1, arg->name);
|
|
|
|
dbg(" Trying \"%s\"", pathname);
|
|
if (access(pathname, F_OK) == 0) { /* We found it */
|
|
pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
|
|
strcpy(pathname, arg->buffer);
|
|
return (pathname);
|
|
}
|
|
}
|
|
return (NULL);
|
|
}
|
|
|
|
static char *
|
|
search_library_path(const char *name, const char *path)
|
|
{
|
|
char *p;
|
|
struct try_library_args arg;
|
|
|
|
if (path == NULL)
|
|
return NULL;
|
|
|
|
arg.name = name;
|
|
arg.namelen = strlen(name);
|
|
arg.buffer = xmalloc(PATH_MAX);
|
|
arg.buflen = PATH_MAX;
|
|
|
|
p = path_enumerate(path, try_library_path, &arg);
|
|
|
|
free(arg.buffer);
|
|
|
|
return (p);
|
|
}
|
|
|
|
int
|
|
dlclose(void *handle)
|
|
{
|
|
Obj_Entry *root;
|
|
int lockstate;
|
|
|
|
lockstate = wlock_acquire(rtld_bind_lock);
|
|
root = dlcheck(handle);
|
|
if (root == NULL) {
|
|
wlock_release(rtld_bind_lock, lockstate);
|
|
return -1;
|
|
}
|
|
|
|
/* Unreference the object and its dependencies. */
|
|
root->dl_refcount--;
|
|
|
|
unref_dag(root);
|
|
|
|
if (root->refcount == 0) {
|
|
/*
|
|
* The object is no longer referenced, so we must unload it.
|
|
* First, call the fini functions with no locks held.
|
|
*/
|
|
wlock_release(rtld_bind_lock, lockstate);
|
|
objlist_call_fini(&list_fini);
|
|
lockstate = wlock_acquire(rtld_bind_lock);
|
|
objlist_remove_unref(&list_fini);
|
|
|
|
/* Finish cleaning up the newly-unreferenced objects. */
|
|
GDB_STATE(RT_DELETE,&root->linkmap);
|
|
unload_object(root);
|
|
GDB_STATE(RT_CONSISTENT,NULL);
|
|
}
|
|
wlock_release(rtld_bind_lock, lockstate);
|
|
return 0;
|
|
}
|
|
|
|
const char *
|
|
dlerror(void)
|
|
{
|
|
char *msg = error_message;
|
|
error_message = NULL;
|
|
return msg;
|
|
}
|
|
|
|
/*
|
|
* This function is deprecated and has no effect.
|
|
*/
|
|
void
|
|
dllockinit(void *context,
|
|
void *(*lock_create)(void *context),
|
|
void (*rlock_acquire)(void *lock),
|
|
void (*wlock_acquire)(void *lock),
|
|
void (*lock_release)(void *lock),
|
|
void (*lock_destroy)(void *lock),
|
|
void (*context_destroy)(void *context))
|
|
{
|
|
static void *cur_context;
|
|
static void (*cur_context_destroy)(void *);
|
|
|
|
/* Just destroy the context from the previous call, if necessary. */
|
|
if (cur_context_destroy != NULL)
|
|
cur_context_destroy(cur_context);
|
|
cur_context = context;
|
|
cur_context_destroy = context_destroy;
|
|
}
|
|
|
|
void *
|
|
dlopen(const char *name, int mode)
|
|
{
|
|
Obj_Entry **old_obj_tail;
|
|
Obj_Entry *obj;
|
|
Objlist initlist;
|
|
int result, lockstate;
|
|
|
|
ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
|
|
if (ld_tracing != NULL)
|
|
environ = (char **)*get_program_var_addr("environ");
|
|
|
|
objlist_init(&initlist);
|
|
|
|
lockstate = wlock_acquire(rtld_bind_lock);
|
|
GDB_STATE(RT_ADD,NULL);
|
|
|
|
old_obj_tail = obj_tail;
|
|
obj = NULL;
|
|
if (name == NULL) {
|
|
obj = obj_main;
|
|
obj->refcount++;
|
|
} else {
|
|
obj = load_object(name, obj_main);
|
|
}
|
|
|
|
if (obj) {
|
|
obj->dl_refcount++;
|
|
if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
|
|
objlist_push_tail(&list_global, obj);
|
|
mode &= RTLD_MODEMASK;
|
|
if (*old_obj_tail != NULL) { /* We loaded something new. */
|
|
assert(*old_obj_tail == obj);
|
|
result = load_needed_objects(obj);
|
|
init_dag(obj);
|
|
if (result != -1)
|
|
result = rtld_verify_versions(&obj->dagmembers);
|
|
if (result != -1 && ld_tracing)
|
|
goto trace;
|
|
if (result == -1 ||
|
|
(relocate_objects(obj, mode == RTLD_NOW, &obj_rtld)) == -1) {
|
|
obj->dl_refcount--;
|
|
unref_dag(obj);
|
|
if (obj->refcount == 0)
|
|
unload_object(obj);
|
|
obj = NULL;
|
|
} else {
|
|
/* Make list of init functions to call. */
|
|
initlist_add_objects(obj, &obj->next, &initlist);
|
|
}
|
|
} else {
|
|
|
|
/* Bump the reference counts for objects on this DAG. */
|
|
ref_dag(obj);
|
|
|
|
if (ld_tracing)
|
|
goto trace;
|
|
}
|
|
}
|
|
|
|
GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
|
|
|
|
/* Call the init functions with no locks held. */
|
|
wlock_release(rtld_bind_lock, lockstate);
|
|
objlist_call_init(&initlist);
|
|
lockstate = wlock_acquire(rtld_bind_lock);
|
|
objlist_clear(&initlist);
|
|
wlock_release(rtld_bind_lock, lockstate);
|
|
return obj;
|
|
trace:
|
|
trace_loaded_objects(obj);
|
|
wlock_release(rtld_bind_lock, lockstate);
|
|
exit(0);
|
|
}
|
|
|
|
static void *
|
|
do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
|
|
int flags)
|
|
{
|
|
const Obj_Entry *obj;
|
|
unsigned long hash;
|
|
const Elf_Sym *def;
|
|
const Obj_Entry *defobj;
|
|
int lockstate;
|
|
|
|
hash = elf_hash(name);
|
|
def = NULL;
|
|
defobj = NULL;
|
|
flags |= SYMLOOK_IN_PLT;
|
|
|
|
lockstate = rlock_acquire(rtld_bind_lock);
|
|
if (handle == NULL || handle == RTLD_NEXT ||
|
|
handle == RTLD_DEFAULT || handle == RTLD_SELF) {
|
|
|
|
if ((obj = obj_from_addr(retaddr)) == NULL) {
|
|
_rtld_error("Cannot determine caller's shared object");
|
|
rlock_release(rtld_bind_lock, lockstate);
|
|
return NULL;
|
|
}
|
|
if (handle == NULL) { /* Just the caller's shared object. */
|
|
def = symlook_obj(name, hash, obj, ve, flags);
|
|
defobj = obj;
|
|
} else if (handle == RTLD_NEXT || /* Objects after caller's */
|
|
handle == RTLD_SELF) { /* ... caller included */
|
|
if (handle == RTLD_NEXT)
|
|
obj = obj->next;
|
|
for (; obj != NULL; obj = obj->next) {
|
|
if ((def = symlook_obj(name, hash, obj, ve, flags)) != NULL) {
|
|
defobj = obj;
|
|
break;
|
|
}
|
|
}
|
|
} else {
|
|
assert(handle == RTLD_DEFAULT);
|
|
def = symlook_default(name, hash, obj, &defobj, ve, flags);
|
|
}
|
|
} else {
|
|
if ((obj = dlcheck(handle)) == NULL) {
|
|
rlock_release(rtld_bind_lock, lockstate);
|
|
return NULL;
|
|
}
|
|
|
|
if (obj->mainprog) {
|
|
DoneList donelist;
|
|
|
|
/* Search main program and all libraries loaded by it. */
|
|
donelist_init(&donelist);
|
|
def = symlook_list(name, hash, &list_main, &defobj, ve, flags,
|
|
&donelist);
|
|
} else {
|
|
/*
|
|
* XXX - This isn't correct. The search should include the whole
|
|
* DAG rooted at the given object.
|
|
*/
|
|
def = symlook_obj(name, hash, obj, ve, flags);
|
|
defobj = obj;
|
|
}
|
|
}
|
|
|
|
if (def != NULL) {
|
|
rlock_release(rtld_bind_lock, lockstate);
|
|
|
|
/*
|
|
* The value required by the caller is derived from the value
|
|
* of the symbol. For the ia64 architecture, we need to
|
|
* construct a function descriptor which the caller can use to
|
|
* call the function with the right 'gp' value. For other
|
|
* architectures and for non-functions, the value is simply
|
|
* the relocated value of the symbol.
|
|
*/
|
|
if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
|
|
return make_function_pointer(def, defobj);
|
|
else
|
|
return defobj->relocbase + def->st_value;
|
|
}
|
|
|
|
_rtld_error("Undefined symbol \"%s\"", name);
|
|
rlock_release(rtld_bind_lock, lockstate);
|
|
return NULL;
|
|
}
|
|
|
|
void *
|
|
dlsym(void *handle, const char *name)
|
|
{
|
|
return do_dlsym(handle, name, __builtin_return_address(0), NULL,
|
|
SYMLOOK_DLSYM);
|
|
}
|
|
|
|
void *
|
|
dlvsym(void *handle, const char *name, const char *version)
|
|
{
|
|
Ver_Entry ventry;
|
|
|
|
ventry.name = version;
|
|
ventry.file = NULL;
|
|
ventry.hash = elf_hash(version);
|
|
ventry.flags= 0;
|
|
return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
|
|
SYMLOOK_DLSYM);
|
|
}
|
|
|
|
int
|
|
dladdr(const void *addr, Dl_info *info)
|
|
{
|
|
const Obj_Entry *obj;
|
|
const Elf_Sym *def;
|
|
void *symbol_addr;
|
|
unsigned long symoffset;
|
|
int lockstate;
|
|
|
|
lockstate = rlock_acquire(rtld_bind_lock);
|
|
obj = obj_from_addr(addr);
|
|
if (obj == NULL) {
|
|
_rtld_error("No shared object contains address");
|
|
rlock_release(rtld_bind_lock, lockstate);
|
|
return 0;
|
|
}
|
|
info->dli_fname = obj->path;
|
|
info->dli_fbase = obj->mapbase;
|
|
info->dli_saddr = (void *)0;
|
|
info->dli_sname = NULL;
|
|
|
|
/*
|
|
* Walk the symbol list looking for the symbol whose address is
|
|
* closest to the address sent in.
|
|
*/
|
|
for (symoffset = 0; symoffset < obj->nchains; symoffset++) {
|
|
def = obj->symtab + symoffset;
|
|
|
|
/*
|
|
* For skip the symbol if st_shndx is either SHN_UNDEF or
|
|
* SHN_COMMON.
|
|
*/
|
|
if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
|
|
continue;
|
|
|
|
/*
|
|
* If the symbol is greater than the specified address, or if it
|
|
* is further away from addr than the current nearest symbol,
|
|
* then reject it.
|
|
*/
|
|
symbol_addr = obj->relocbase + def->st_value;
|
|
if (symbol_addr > addr || symbol_addr < info->dli_saddr)
|
|
continue;
|
|
|
|
/* Update our idea of the nearest symbol. */
|
|
info->dli_sname = obj->strtab + def->st_name;
|
|
info->dli_saddr = symbol_addr;
|
|
|
|
/* Exact match? */
|
|
if (info->dli_saddr == addr)
|
|
break;
|
|
}
|
|
rlock_release(rtld_bind_lock, lockstate);
|
|
return 1;
|
|
}
|
|
|
|
int
|
|
dlinfo(void *handle, int request, void *p)
|
|
{
|
|
const Obj_Entry *obj;
|
|
int error, lockstate;
|
|
|
|
lockstate = rlock_acquire(rtld_bind_lock);
|
|
|
|
if (handle == NULL || handle == RTLD_SELF) {
|
|
void *retaddr;
|
|
|
|
retaddr = __builtin_return_address(0); /* __GNUC__ only */
|
|
if ((obj = obj_from_addr(retaddr)) == NULL)
|
|
_rtld_error("Cannot determine caller's shared object");
|
|
} else
|
|
obj = dlcheck(handle);
|
|
|
|
if (obj == NULL) {
|
|
rlock_release(rtld_bind_lock, lockstate);
|
|
return (-1);
|
|
}
|
|
|
|
error = 0;
|
|
switch (request) {
|
|
case RTLD_DI_LINKMAP:
|
|
*((struct link_map const **)p) = &obj->linkmap;
|
|
break;
|
|
case RTLD_DI_ORIGIN:
|
|
error = rtld_dirname(obj->path, p);
|
|
break;
|
|
|
|
case RTLD_DI_SERINFOSIZE:
|
|
case RTLD_DI_SERINFO:
|
|
error = do_search_info(obj, request, (struct dl_serinfo *)p);
|
|
break;
|
|
|
|
default:
|
|
_rtld_error("Invalid request %d passed to dlinfo()", request);
|
|
error = -1;
|
|
}
|
|
|
|
rlock_release(rtld_bind_lock, lockstate);
|
|
|
|
return (error);
|
|
}
|
|
|
|
struct fill_search_info_args {
|
|
int request;
|
|
unsigned int flags;
|
|
Dl_serinfo *serinfo;
|
|
Dl_serpath *serpath;
|
|
char *strspace;
|
|
};
|
|
|
|
static void *
|
|
fill_search_info(const char *dir, size_t dirlen, void *param)
|
|
{
|
|
struct fill_search_info_args *arg;
|
|
|
|
arg = param;
|
|
|
|
if (arg->request == RTLD_DI_SERINFOSIZE) {
|
|
arg->serinfo->dls_cnt ++;
|
|
arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1;
|
|
} else {
|
|
struct dl_serpath *s_entry;
|
|
|
|
s_entry = arg->serpath;
|
|
s_entry->dls_name = arg->strspace;
|
|
s_entry->dls_flags = arg->flags;
|
|
|
|
strncpy(arg->strspace, dir, dirlen);
|
|
arg->strspace[dirlen] = '\0';
|
|
|
|
arg->strspace += dirlen + 1;
|
|
arg->serpath++;
|
|
}
|
|
|
|
return (NULL);
|
|
}
|
|
|
|
static int
|
|
do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
|
|
{
|
|
struct dl_serinfo _info;
|
|
struct fill_search_info_args args;
|
|
|
|
args.request = RTLD_DI_SERINFOSIZE;
|
|
args.serinfo = &_info;
|
|
|
|
_info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
|
|
_info.dls_cnt = 0;
|
|
|
|
path_enumerate(ld_library_path, fill_search_info, &args);
|
|
path_enumerate(obj->rpath, fill_search_info, &args);
|
|
path_enumerate(gethints(), fill_search_info, &args);
|
|
path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
|
|
|
|
|
|
if (request == RTLD_DI_SERINFOSIZE) {
|
|
info->dls_size = _info.dls_size;
|
|
info->dls_cnt = _info.dls_cnt;
|
|
return (0);
|
|
}
|
|
|
|
if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
|
|
_rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
|
|
return (-1);
|
|
}
|
|
|
|
args.request = RTLD_DI_SERINFO;
|
|
args.serinfo = info;
|
|
args.serpath = &info->dls_serpath[0];
|
|
args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
|
|
|
|
args.flags = LA_SER_LIBPATH;
|
|
if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
|
|
return (-1);
|
|
|
|
args.flags = LA_SER_RUNPATH;
|
|
if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
|
|
return (-1);
|
|
|
|
args.flags = LA_SER_CONFIG;
|
|
if (path_enumerate(gethints(), fill_search_info, &args) != NULL)
|
|
return (-1);
|
|
|
|
args.flags = LA_SER_DEFAULT;
|
|
if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
|
|
return (-1);
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
rtld_dirname(const char *path, char *bname)
|
|
{
|
|
const char *endp;
|
|
|
|
/* Empty or NULL string gets treated as "." */
|
|
if (path == NULL || *path == '\0') {
|
|
bname[0] = '.';
|
|
bname[1] = '\0';
|
|
return (0);
|
|
}
|
|
|
|
/* Strip trailing slashes */
|
|
endp = path + strlen(path) - 1;
|
|
while (endp > path && *endp == '/')
|
|
endp--;
|
|
|
|
/* Find the start of the dir */
|
|
while (endp > path && *endp != '/')
|
|
endp--;
|
|
|
|
/* Either the dir is "/" or there are no slashes */
|
|
if (endp == path) {
|
|
bname[0] = *endp == '/' ? '/' : '.';
|
|
bname[1] = '\0';
|
|
return (0);
|
|
} else {
|
|
do {
|
|
endp--;
|
|
} while (endp > path && *endp == '/');
|
|
}
|
|
|
|
if (endp - path + 2 > PATH_MAX)
|
|
{
|
|
_rtld_error("Filename is too long: %s", path);
|
|
return(-1);
|
|
}
|
|
|
|
strncpy(bname, path, endp - path + 1);
|
|
bname[endp - path + 1] = '\0';
|
|
return (0);
|
|
}
|
|
|
|
static void
|
|
linkmap_add(Obj_Entry *obj)
|
|
{
|
|
struct link_map *l = &obj->linkmap;
|
|
struct link_map *prev;
|
|
|
|
obj->linkmap.l_name = obj->path;
|
|
obj->linkmap.l_addr = obj->mapbase;
|
|
obj->linkmap.l_ld = obj->dynamic;
|
|
#ifdef __mips__
|
|
/* GDB needs load offset on MIPS to use the symbols */
|
|
obj->linkmap.l_offs = obj->relocbase;
|
|
#endif
|
|
|
|
if (r_debug.r_map == NULL) {
|
|
r_debug.r_map = l;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Scan to the end of the list, but not past the entry for the
|
|
* dynamic linker, which we want to keep at the very end.
|
|
*/
|
|
for (prev = r_debug.r_map;
|
|
prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
|
|
prev = prev->l_next)
|
|
;
|
|
|
|
/* Link in the new entry. */
|
|
l->l_prev = prev;
|
|
l->l_next = prev->l_next;
|
|
if (l->l_next != NULL)
|
|
l->l_next->l_prev = l;
|
|
prev->l_next = l;
|
|
}
|
|
|
|
static void
|
|
linkmap_delete(Obj_Entry *obj)
|
|
{
|
|
struct link_map *l = &obj->linkmap;
|
|
|
|
if (l->l_prev == NULL) {
|
|
if ((r_debug.r_map = l->l_next) != NULL)
|
|
l->l_next->l_prev = NULL;
|
|
return;
|
|
}
|
|
|
|
if ((l->l_prev->l_next = l->l_next) != NULL)
|
|
l->l_next->l_prev = l->l_prev;
|
|
}
|
|
|
|
/*
|
|
* Function for the debugger to set a breakpoint on to gain control.
|
|
*
|
|
* The two parameters allow the debugger to easily find and determine
|
|
* what the runtime loader is doing and to whom it is doing it.
|
|
*
|
|
* When the loadhook trap is hit (r_debug_state, set at program
|
|
* initialization), the arguments can be found on the stack:
|
|
*
|
|
* +8 struct link_map *m
|
|
* +4 struct r_debug *rd
|
|
* +0 RetAddr
|
|
*/
|
|
void
|
|
r_debug_state(struct r_debug* rd, struct link_map *m)
|
|
{
|
|
}
|
|
|
|
/*
|
|
* Get address of the pointer variable in the main program.
|
|
*/
|
|
static const void **
|
|
get_program_var_addr(const char *name)
|
|
{
|
|
const Obj_Entry *obj;
|
|
unsigned long hash;
|
|
|
|
hash = elf_hash(name);
|
|
for (obj = obj_main; obj != NULL; obj = obj->next) {
|
|
const Elf_Sym *def;
|
|
|
|
if ((def = symlook_obj(name, hash, obj, NULL, 0)) != NULL) {
|
|
const void **addr;
|
|
|
|
addr = (const void **)(obj->relocbase + def->st_value);
|
|
return addr;
|
|
}
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Set a pointer variable in the main program to the given value. This
|
|
* is used to set key variables such as "environ" before any of the
|
|
* init functions are called.
|
|
*/
|
|
static void
|
|
set_program_var(const char *name, const void *value)
|
|
{
|
|
const void **addr;
|
|
|
|
if ((addr = get_program_var_addr(name)) != NULL) {
|
|
dbg("\"%s\": *%p <-- %p", name, addr, value);
|
|
*addr = value;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Given a symbol name in a referencing object, find the corresponding
|
|
* definition of the symbol. Returns a pointer to the symbol, or NULL if
|
|
* no definition was found. Returns a pointer to the Obj_Entry of the
|
|
* defining object via the reference parameter DEFOBJ_OUT.
|
|
*/
|
|
static const Elf_Sym *
|
|
symlook_default(const char *name, unsigned long hash, const Obj_Entry *refobj,
|
|
const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags)
|
|
{
|
|
DoneList donelist;
|
|
const Elf_Sym *def;
|
|
const Elf_Sym *symp;
|
|
const Obj_Entry *obj;
|
|
const Obj_Entry *defobj;
|
|
const Objlist_Entry *elm;
|
|
def = NULL;
|
|
defobj = NULL;
|
|
donelist_init(&donelist);
|
|
|
|
/* Look first in the referencing object if linked symbolically. */
|
|
if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
|
|
symp = symlook_obj(name, hash, refobj, ventry, flags);
|
|
if (symp != NULL) {
|
|
def = symp;
|
|
defobj = refobj;
|
|
}
|
|
}
|
|
|
|
/* Search all objects loaded at program start up. */
|
|
if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
|
|
symp = symlook_list(name, hash, &list_main, &obj, ventry, flags,
|
|
&donelist);
|
|
if (symp != NULL &&
|
|
(def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) {
|
|
def = symp;
|
|
defobj = obj;
|
|
}
|
|
}
|
|
|
|
/* Search all DAGs whose roots are RTLD_GLOBAL objects. */
|
|
STAILQ_FOREACH(elm, &list_global, link) {
|
|
if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK)
|
|
break;
|
|
symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry,
|
|
flags, &donelist);
|
|
if (symp != NULL &&
|
|
(def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) {
|
|
def = symp;
|
|
defobj = obj;
|
|
}
|
|
}
|
|
|
|
/* Search all dlopened DAGs containing the referencing object. */
|
|
STAILQ_FOREACH(elm, &refobj->dldags, link) {
|
|
if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK)
|
|
break;
|
|
symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry,
|
|
flags, &donelist);
|
|
if (symp != NULL &&
|
|
(def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) {
|
|
def = symp;
|
|
defobj = obj;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Search the dynamic linker itself, and possibly resolve the
|
|
* symbol from there. This is how the application links to
|
|
* dynamic linker services such as dlopen. Only the values listed
|
|
* in the "exports" array can be resolved from the dynamic linker.
|
|
*/
|
|
if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
|
|
symp = symlook_obj(name, hash, &obj_rtld, ventry, flags);
|
|
if (symp != NULL && is_exported(symp)) {
|
|
def = symp;
|
|
defobj = &obj_rtld;
|
|
}
|
|
}
|
|
|
|
if (def != NULL)
|
|
*defobj_out = defobj;
|
|
return def;
|
|
}
|
|
|
|
static const Elf_Sym *
|
|
symlook_list(const char *name, unsigned long hash, Objlist *objlist,
|
|
const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags,
|
|
DoneList *dlp)
|
|
{
|
|
const Elf_Sym *symp;
|
|
const Elf_Sym *def;
|
|
const Obj_Entry *defobj;
|
|
const Objlist_Entry *elm;
|
|
|
|
def = NULL;
|
|
defobj = NULL;
|
|
STAILQ_FOREACH(elm, objlist, link) {
|
|
if (donelist_check(dlp, elm->obj))
|
|
continue;
|
|
if ((symp = symlook_obj(name, hash, elm->obj, ventry, flags)) != NULL) {
|
|
if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) {
|
|
def = symp;
|
|
defobj = elm->obj;
|
|
if (ELF_ST_BIND(def->st_info) != STB_WEAK)
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
if (def != NULL)
|
|
*defobj_out = defobj;
|
|
return def;
|
|
}
|
|
|
|
/*
|
|
* Search the symbol table of a single shared object for a symbol of
|
|
* the given name and version, if requested. Returns a pointer to the
|
|
* symbol, or NULL if no definition was found.
|
|
*
|
|
* The symbol's hash value is passed in for efficiency reasons; that
|
|
* eliminates many recomputations of the hash value.
|
|
*/
|
|
const Elf_Sym *
|
|
symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj,
|
|
const Ver_Entry *ventry, int flags)
|
|
{
|
|
unsigned long symnum;
|
|
const Elf_Sym *vsymp;
|
|
Elf_Versym verndx;
|
|
int vcount;
|
|
|
|
if (obj->buckets == NULL)
|
|
return NULL;
|
|
|
|
vsymp = NULL;
|
|
vcount = 0;
|
|
symnum = obj->buckets[hash % obj->nbuckets];
|
|
|
|
for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
|
|
const Elf_Sym *symp;
|
|
const char *strp;
|
|
|
|
if (symnum >= obj->nchains)
|
|
return NULL; /* Bad object */
|
|
|
|
symp = obj->symtab + symnum;
|
|
strp = obj->strtab + symp->st_name;
|
|
|
|
switch (ELF_ST_TYPE(symp->st_info)) {
|
|
case STT_FUNC:
|
|
case STT_NOTYPE:
|
|
case STT_OBJECT:
|
|
if (symp->st_value == 0)
|
|
continue;
|
|
/* fallthrough */
|
|
case STT_TLS:
|
|
if (symp->st_shndx != SHN_UNDEF ||
|
|
((flags & SYMLOOK_IN_PLT) == 0 &&
|
|
ELF_ST_TYPE(symp->st_info) == STT_FUNC))
|
|
break;
|
|
/* fallthrough */
|
|
default:
|
|
continue;
|
|
}
|
|
if (name[0] != strp[0] || strcmp(name, strp) != 0)
|
|
continue;
|
|
|
|
if (ventry == NULL) {
|
|
if (obj->versyms != NULL) {
|
|
verndx = VER_NDX(obj->versyms[symnum]);
|
|
if (verndx > obj->vernum) {
|
|
_rtld_error("%s: symbol %s references wrong version %d",
|
|
obj->path, obj->strtab + symnum, verndx);
|
|
continue;
|
|
}
|
|
/*
|
|
* If we are not called from dlsym (i.e. this is a normal
|
|
* relocation from unversioned binary, accept the symbol
|
|
* immediately if it happens to have first version after
|
|
* this shared object became versioned. Otherwise, if
|
|
* symbol is versioned and not hidden, remember it. If it
|
|
* is the only symbol with this name exported by the
|
|
* shared object, it will be returned as a match at the
|
|
* end of the function. If symbol is global (verndx < 2)
|
|
* accept it unconditionally.
|
|
*/
|
|
if ((flags & SYMLOOK_DLSYM) == 0 && verndx == VER_NDX_GIVEN)
|
|
return symp;
|
|
else if (verndx >= VER_NDX_GIVEN) {
|
|
if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) {
|
|
if (vsymp == NULL)
|
|
vsymp = symp;
|
|
vcount ++;
|
|
}
|
|
continue;
|
|
}
|
|
}
|
|
return symp;
|
|
} else {
|
|
if (obj->versyms == NULL) {
|
|
if (object_match_name(obj, ventry->name)) {
|
|
_rtld_error("%s: object %s should provide version %s for "
|
|
"symbol %s", obj_rtld.path, obj->path, ventry->name,
|
|
obj->strtab + symnum);
|
|
continue;
|
|
}
|
|
} else {
|
|
verndx = VER_NDX(obj->versyms[symnum]);
|
|
if (verndx > obj->vernum) {
|
|
_rtld_error("%s: symbol %s references wrong version %d",
|
|
obj->path, obj->strtab + symnum, verndx);
|
|
continue;
|
|
}
|
|
if (obj->vertab[verndx].hash != ventry->hash ||
|
|
strcmp(obj->vertab[verndx].name, ventry->name)) {
|
|
/*
|
|
* Version does not match. Look if this is a global symbol
|
|
* and if it is not hidden. If global symbol (verndx < 2)
|
|
* is available, use it. Do not return symbol if we are
|
|
* called by dlvsym, because dlvsym looks for a specific
|
|
* version and default one is not what dlvsym wants.
|
|
*/
|
|
if ((flags & SYMLOOK_DLSYM) ||
|
|
(obj->versyms[symnum] & VER_NDX_HIDDEN) ||
|
|
(verndx >= VER_NDX_GIVEN))
|
|
continue;
|
|
}
|
|
}
|
|
return symp;
|
|
}
|
|
}
|
|
return (vcount == 1) ? vsymp : NULL;
|
|
}
|
|
|
|
static void
|
|
trace_loaded_objects(Obj_Entry *obj)
|
|
{
|
|
char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
|
|
int c;
|
|
|
|
if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
|
|
main_local = "";
|
|
|
|
if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
|
|
fmt1 = "\t%o => %p (%x)\n";
|
|
|
|
if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
|
|
fmt2 = "\t%o (%x)\n";
|
|
|
|
list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
|
|
|
|
for (; obj; obj = obj->next) {
|
|
Needed_Entry *needed;
|
|
char *name, *path;
|
|
bool is_lib;
|
|
|
|
if (list_containers && obj->needed != NULL)
|
|
printf("%s:\n", obj->path);
|
|
for (needed = obj->needed; needed; needed = needed->next) {
|
|
if (needed->obj != NULL) {
|
|
if (needed->obj->traced && !list_containers)
|
|
continue;
|
|
needed->obj->traced = true;
|
|
path = needed->obj->path;
|
|
} else
|
|
path = "not found";
|
|
|
|
name = (char *)obj->strtab + needed->name;
|
|
is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
|
|
|
|
fmt = is_lib ? fmt1 : fmt2;
|
|
while ((c = *fmt++) != '\0') {
|
|
switch (c) {
|
|
default:
|
|
putchar(c);
|
|
continue;
|
|
case '\\':
|
|
switch (c = *fmt) {
|
|
case '\0':
|
|
continue;
|
|
case 'n':
|
|
putchar('\n');
|
|
break;
|
|
case 't':
|
|
putchar('\t');
|
|
break;
|
|
}
|
|
break;
|
|
case '%':
|
|
switch (c = *fmt) {
|
|
case '\0':
|
|
continue;
|
|
case '%':
|
|
default:
|
|
putchar(c);
|
|
break;
|
|
case 'A':
|
|
printf("%s", main_local);
|
|
break;
|
|
case 'a':
|
|
printf("%s", obj_main->path);
|
|
break;
|
|
case 'o':
|
|
printf("%s", name);
|
|
break;
|
|
#if 0
|
|
case 'm':
|
|
printf("%d", sodp->sod_major);
|
|
break;
|
|
case 'n':
|
|
printf("%d", sodp->sod_minor);
|
|
break;
|
|
#endif
|
|
case 'p':
|
|
printf("%s", path);
|
|
break;
|
|
case 'x':
|
|
printf("%p", needed->obj ? needed->obj->mapbase : 0);
|
|
break;
|
|
}
|
|
break;
|
|
}
|
|
++fmt;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Unload a dlopened object and its dependencies from memory and from
|
|
* our data structures. It is assumed that the DAG rooted in the
|
|
* object has already been unreferenced, and that the object has a
|
|
* reference count of 0.
|
|
*/
|
|
static void
|
|
unload_object(Obj_Entry *root)
|
|
{
|
|
Obj_Entry *obj;
|
|
Obj_Entry **linkp;
|
|
|
|
assert(root->refcount == 0);
|
|
|
|
/*
|
|
* Pass over the DAG removing unreferenced objects from
|
|
* appropriate lists.
|
|
*/
|
|
unlink_object(root);
|
|
|
|
/* Unmap all objects that are no longer referenced. */
|
|
linkp = &obj_list->next;
|
|
while ((obj = *linkp) != NULL) {
|
|
if (obj->refcount == 0) {
|
|
dbg("unloading \"%s\"", obj->path);
|
|
munmap(obj->mapbase, obj->mapsize);
|
|
linkmap_delete(obj);
|
|
*linkp = obj->next;
|
|
obj_count--;
|
|
obj_free(obj);
|
|
} else
|
|
linkp = &obj->next;
|
|
}
|
|
obj_tail = linkp;
|
|
}
|
|
|
|
static void
|
|
unlink_object(Obj_Entry *root)
|
|
{
|
|
Objlist_Entry *elm;
|
|
|
|
if (root->refcount == 0) {
|
|
/* Remove the object from the RTLD_GLOBAL list. */
|
|
objlist_remove(&list_global, root);
|
|
|
|
/* Remove the object from all objects' DAG lists. */
|
|
STAILQ_FOREACH(elm, &root->dagmembers, link) {
|
|
objlist_remove(&elm->obj->dldags, root);
|
|
if (elm->obj != root)
|
|
unlink_object(elm->obj);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void
|
|
ref_dag(Obj_Entry *root)
|
|
{
|
|
Objlist_Entry *elm;
|
|
|
|
STAILQ_FOREACH(elm, &root->dagmembers, link)
|
|
elm->obj->refcount++;
|
|
}
|
|
|
|
static void
|
|
unref_dag(Obj_Entry *root)
|
|
{
|
|
Objlist_Entry *elm;
|
|
|
|
STAILQ_FOREACH(elm, &root->dagmembers, link)
|
|
elm->obj->refcount--;
|
|
}
|
|
|
|
/*
|
|
* Common code for MD __tls_get_addr().
|
|
*/
|
|
void *
|
|
tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset)
|
|
{
|
|
Elf_Addr* dtv = *dtvp;
|
|
int lockstate;
|
|
|
|
/* Check dtv generation in case new modules have arrived */
|
|
if (dtv[0] != tls_dtv_generation) {
|
|
Elf_Addr* newdtv;
|
|
int to_copy;
|
|
|
|
lockstate = wlock_acquire(rtld_bind_lock);
|
|
newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr));
|
|
to_copy = dtv[1];
|
|
if (to_copy > tls_max_index)
|
|
to_copy = tls_max_index;
|
|
memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
|
|
newdtv[0] = tls_dtv_generation;
|
|
newdtv[1] = tls_max_index;
|
|
free(dtv);
|
|
wlock_release(rtld_bind_lock, lockstate);
|
|
*dtvp = newdtv;
|
|
}
|
|
|
|
/* Dynamically allocate module TLS if necessary */
|
|
if (!dtv[index + 1]) {
|
|
/* Signal safe, wlock will block out signals. */
|
|
lockstate = wlock_acquire(rtld_bind_lock);
|
|
if (!dtv[index + 1])
|
|
dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
|
|
wlock_release(rtld_bind_lock, lockstate);
|
|
}
|
|
return (void*) (dtv[index + 1] + offset);
|
|
}
|
|
|
|
/* XXX not sure what variants to use for arm. */
|
|
|
|
#if defined(__ia64__) || defined(__alpha__) || defined(__powerpc__)
|
|
|
|
/*
|
|
* Allocate Static TLS using the Variant I method.
|
|
*/
|
|
void *
|
|
allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
|
|
{
|
|
Obj_Entry *obj;
|
|
size_t size;
|
|
char *tls;
|
|
Elf_Addr *dtv, *olddtv;
|
|
Elf_Addr addr;
|
|
int i;
|
|
|
|
size = tls_static_space;
|
|
|
|
tls = calloc(1, size);
|
|
dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr));
|
|
|
|
*(Elf_Addr**) tls = dtv;
|
|
|
|
dtv[0] = tls_dtv_generation;
|
|
dtv[1] = tls_max_index;
|
|
|
|
if (oldtls) {
|
|
/*
|
|
* Copy the static TLS block over whole.
|
|
*/
|
|
memcpy(tls + tcbsize, oldtls + tcbsize, tls_static_space - tcbsize);
|
|
|
|
/*
|
|
* If any dynamic TLS blocks have been created tls_get_addr(),
|
|
* move them over.
|
|
*/
|
|
olddtv = *(Elf_Addr**) oldtls;
|
|
for (i = 0; i < olddtv[1]; i++) {
|
|
if (olddtv[i+2] < (Elf_Addr)oldtls ||
|
|
olddtv[i+2] > (Elf_Addr)oldtls + tls_static_space) {
|
|
dtv[i+2] = olddtv[i+2];
|
|
olddtv[i+2] = 0;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* We assume that all tls blocks are allocated with the same
|
|
* size and alignment.
|
|
*/
|
|
free_tls(oldtls, tcbsize, tcbalign);
|
|
} else {
|
|
for (obj = objs; obj; obj = obj->next) {
|
|
if (obj->tlsoffset) {
|
|
addr = (Elf_Addr)tls + obj->tlsoffset;
|
|
memset((void*) (addr + obj->tlsinitsize),
|
|
0, obj->tlssize - obj->tlsinitsize);
|
|
if (obj->tlsinit)
|
|
memcpy((void*) addr, obj->tlsinit,
|
|
obj->tlsinitsize);
|
|
dtv[obj->tlsindex + 1] = addr;
|
|
}
|
|
}
|
|
}
|
|
|
|
return tls;
|
|
}
|
|
|
|
void
|
|
free_tls(void *tls, size_t tcbsize, size_t tcbalign)
|
|
{
|
|
size_t size;
|
|
Elf_Addr* dtv;
|
|
int dtvsize, i;
|
|
Elf_Addr tlsstart, tlsend;
|
|
|
|
/*
|
|
* Figure out the size of the initial TLS block so that we can
|
|
* find stuff which __tls_get_addr() allocated dynamically.
|
|
*/
|
|
size = tls_static_space;
|
|
|
|
dtv = ((Elf_Addr**)tls)[0];
|
|
dtvsize = dtv[1];
|
|
tlsstart = (Elf_Addr) tls;
|
|
tlsend = tlsstart + size;
|
|
for (i = 0; i < dtvsize; i++) {
|
|
if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) {
|
|
free((void*) dtv[i+2]);
|
|
}
|
|
}
|
|
|
|
free((void*) tlsstart);
|
|
}
|
|
|
|
#endif
|
|
|
|
#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \
|
|
defined(__arm__)
|
|
|
|
/*
|
|
* Allocate Static TLS using the Variant II method.
|
|
*/
|
|
void *
|
|
allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
|
|
{
|
|
Obj_Entry *obj;
|
|
size_t size;
|
|
char *tls;
|
|
Elf_Addr *dtv, *olddtv;
|
|
Elf_Addr segbase, oldsegbase, addr;
|
|
int i;
|
|
|
|
size = round(tls_static_space, tcbalign);
|
|
|
|
assert(tcbsize >= 2*sizeof(Elf_Addr));
|
|
tls = calloc(1, size + tcbsize);
|
|
dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr));
|
|
|
|
segbase = (Elf_Addr)(tls + size);
|
|
((Elf_Addr*)segbase)[0] = segbase;
|
|
((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
|
|
|
|
dtv[0] = tls_dtv_generation;
|
|
dtv[1] = tls_max_index;
|
|
|
|
if (oldtls) {
|
|
/*
|
|
* Copy the static TLS block over whole.
|
|
*/
|
|
oldsegbase = (Elf_Addr) oldtls;
|
|
memcpy((void *)(segbase - tls_static_space),
|
|
(const void *)(oldsegbase - tls_static_space),
|
|
tls_static_space);
|
|
|
|
/*
|
|
* If any dynamic TLS blocks have been created tls_get_addr(),
|
|
* move them over.
|
|
*/
|
|
olddtv = ((Elf_Addr**)oldsegbase)[1];
|
|
for (i = 0; i < olddtv[1]; i++) {
|
|
if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
|
|
dtv[i+2] = olddtv[i+2];
|
|
olddtv[i+2] = 0;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* We assume that this block was the one we created with
|
|
* allocate_initial_tls().
|
|
*/
|
|
free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
|
|
} else {
|
|
for (obj = objs; obj; obj = obj->next) {
|
|
if (obj->tlsoffset) {
|
|
addr = segbase - obj->tlsoffset;
|
|
memset((void*) (addr + obj->tlsinitsize),
|
|
0, obj->tlssize - obj->tlsinitsize);
|
|
if (obj->tlsinit)
|
|
memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
|
|
dtv[obj->tlsindex + 1] = addr;
|
|
}
|
|
}
|
|
}
|
|
|
|
return (void*) segbase;
|
|
}
|
|
|
|
void
|
|
free_tls(void *tls, size_t tcbsize, size_t tcbalign)
|
|
{
|
|
size_t size;
|
|
Elf_Addr* dtv;
|
|
int dtvsize, i;
|
|
Elf_Addr tlsstart, tlsend;
|
|
|
|
/*
|
|
* Figure out the size of the initial TLS block so that we can
|
|
* find stuff which ___tls_get_addr() allocated dynamically.
|
|
*/
|
|
size = round(tls_static_space, tcbalign);
|
|
|
|
dtv = ((Elf_Addr**)tls)[1];
|
|
dtvsize = dtv[1];
|
|
tlsend = (Elf_Addr) tls;
|
|
tlsstart = tlsend - size;
|
|
for (i = 0; i < dtvsize; i++) {
|
|
if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) {
|
|
free((void*) dtv[i+2]);
|
|
}
|
|
}
|
|
|
|
free((void*) tlsstart);
|
|
}
|
|
|
|
#endif
|
|
|
|
/*
|
|
* Allocate TLS block for module with given index.
|
|
*/
|
|
void *
|
|
allocate_module_tls(int index)
|
|
{
|
|
Obj_Entry* obj;
|
|
char* p;
|
|
|
|
for (obj = obj_list; obj; obj = obj->next) {
|
|
if (obj->tlsindex == index)
|
|
break;
|
|
}
|
|
if (!obj) {
|
|
_rtld_error("Can't find module with TLS index %d", index);
|
|
die();
|
|
}
|
|
|
|
p = malloc(obj->tlssize);
|
|
memcpy(p, obj->tlsinit, obj->tlsinitsize);
|
|
memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
|
|
|
|
return p;
|
|
}
|
|
|
|
bool
|
|
allocate_tls_offset(Obj_Entry *obj)
|
|
{
|
|
size_t off;
|
|
|
|
if (obj->tls_done)
|
|
return true;
|
|
|
|
if (obj->tlssize == 0) {
|
|
obj->tls_done = true;
|
|
return true;
|
|
}
|
|
|
|
if (obj->tlsindex == 1)
|
|
off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
|
|
else
|
|
off = calculate_tls_offset(tls_last_offset, tls_last_size,
|
|
obj->tlssize, obj->tlsalign);
|
|
|
|
/*
|
|
* If we have already fixed the size of the static TLS block, we
|
|
* must stay within that size. When allocating the static TLS, we
|
|
* leave a small amount of space spare to be used for dynamically
|
|
* loading modules which use static TLS.
|
|
*/
|
|
if (tls_static_space) {
|
|
if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
|
|
return false;
|
|
}
|
|
|
|
tls_last_offset = obj->tlsoffset = off;
|
|
tls_last_size = obj->tlssize;
|
|
obj->tls_done = true;
|
|
|
|
return true;
|
|
}
|
|
|
|
void
|
|
free_tls_offset(Obj_Entry *obj)
|
|
{
|
|
#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \
|
|
defined(__arm__)
|
|
/*
|
|
* If we were the last thing to allocate out of the static TLS
|
|
* block, we give our space back to the 'allocator'. This is a
|
|
* simplistic workaround to allow libGL.so.1 to be loaded and
|
|
* unloaded multiple times. We only handle the Variant II
|
|
* mechanism for now - this really needs a proper allocator.
|
|
*/
|
|
if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
|
|
== calculate_tls_end(tls_last_offset, tls_last_size)) {
|
|
tls_last_offset -= obj->tlssize;
|
|
tls_last_size = 0;
|
|
}
|
|
#endif
|
|
}
|
|
|
|
void *
|
|
_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
|
|
{
|
|
void *ret;
|
|
int lockstate;
|
|
|
|
lockstate = wlock_acquire(rtld_bind_lock);
|
|
ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
|
|
wlock_release(rtld_bind_lock, lockstate);
|
|
return (ret);
|
|
}
|
|
|
|
void
|
|
_rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
|
|
{
|
|
int lockstate;
|
|
|
|
lockstate = wlock_acquire(rtld_bind_lock);
|
|
free_tls(tcb, tcbsize, tcbalign);
|
|
wlock_release(rtld_bind_lock, lockstate);
|
|
}
|
|
|
|
static void
|
|
object_add_name(Obj_Entry *obj, const char *name)
|
|
{
|
|
Name_Entry *entry;
|
|
size_t len;
|
|
|
|
len = strlen(name);
|
|
entry = malloc(sizeof(Name_Entry) + len);
|
|
|
|
if (entry != NULL) {
|
|
strcpy(entry->name, name);
|
|
STAILQ_INSERT_TAIL(&obj->names, entry, link);
|
|
}
|
|
}
|
|
|
|
static int
|
|
object_match_name(const Obj_Entry *obj, const char *name)
|
|
{
|
|
Name_Entry *entry;
|
|
|
|
STAILQ_FOREACH(entry, &obj->names, link) {
|
|
if (strcmp(name, entry->name) == 0)
|
|
return (1);
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
static Obj_Entry *
|
|
locate_dependency(const Obj_Entry *obj, const char *name)
|
|
{
|
|
const Objlist_Entry *entry;
|
|
const Needed_Entry *needed;
|
|
|
|
STAILQ_FOREACH(entry, &list_main, link) {
|
|
if (object_match_name(entry->obj, name))
|
|
return entry->obj;
|
|
}
|
|
|
|
for (needed = obj->needed; needed != NULL; needed = needed->next) {
|
|
if (needed->obj == NULL)
|
|
continue;
|
|
if (object_match_name(needed->obj, name))
|
|
return needed->obj;
|
|
}
|
|
_rtld_error("%s: Unexpected inconsistency: dependency %s not found",
|
|
obj->path, name);
|
|
die();
|
|
}
|
|
|
|
static int
|
|
check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
|
|
const Elf_Vernaux *vna)
|
|
{
|
|
const Elf_Verdef *vd;
|
|
const char *vername;
|
|
|
|
vername = refobj->strtab + vna->vna_name;
|
|
vd = depobj->verdef;
|
|
if (vd == NULL) {
|
|
_rtld_error("%s: version %s required by %s not defined",
|
|
depobj->path, vername, refobj->path);
|
|
return (-1);
|
|
}
|
|
for (;;) {
|
|
if (vd->vd_version != VER_DEF_CURRENT) {
|
|
_rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
|
|
depobj->path, vd->vd_version);
|
|
return (-1);
|
|
}
|
|
if (vna->vna_hash == vd->vd_hash) {
|
|
const Elf_Verdaux *aux = (const Elf_Verdaux *)
|
|
((char *)vd + vd->vd_aux);
|
|
if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
|
|
return (0);
|
|
}
|
|
if (vd->vd_next == 0)
|
|
break;
|
|
vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
|
|
}
|
|
if (vna->vna_flags & VER_FLG_WEAK)
|
|
return (0);
|
|
_rtld_error("%s: version %s required by %s not found",
|
|
depobj->path, vername, refobj->path);
|
|
return (-1);
|
|
}
|
|
|
|
static int
|
|
rtld_verify_object_versions(Obj_Entry *obj)
|
|
{
|
|
const Elf_Verneed *vn;
|
|
const Elf_Verdef *vd;
|
|
const Elf_Verdaux *vda;
|
|
const Elf_Vernaux *vna;
|
|
const Obj_Entry *depobj;
|
|
int maxvernum, vernum;
|
|
|
|
maxvernum = 0;
|
|
/*
|
|
* Walk over defined and required version records and figure out
|
|
* max index used by any of them. Do very basic sanity checking
|
|
* while there.
|
|
*/
|
|
vn = obj->verneed;
|
|
while (vn != NULL) {
|
|
if (vn->vn_version != VER_NEED_CURRENT) {
|
|
_rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
|
|
obj->path, vn->vn_version);
|
|
return (-1);
|
|
}
|
|
vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
|
|
for (;;) {
|
|
vernum = VER_NEED_IDX(vna->vna_other);
|
|
if (vernum > maxvernum)
|
|
maxvernum = vernum;
|
|
if (vna->vna_next == 0)
|
|
break;
|
|
vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
|
|
}
|
|
if (vn->vn_next == 0)
|
|
break;
|
|
vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
|
|
}
|
|
|
|
vd = obj->verdef;
|
|
while (vd != NULL) {
|
|
if (vd->vd_version != VER_DEF_CURRENT) {
|
|
_rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
|
|
obj->path, vd->vd_version);
|
|
return (-1);
|
|
}
|
|
vernum = VER_DEF_IDX(vd->vd_ndx);
|
|
if (vernum > maxvernum)
|
|
maxvernum = vernum;
|
|
if (vd->vd_next == 0)
|
|
break;
|
|
vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
|
|
}
|
|
|
|
if (maxvernum == 0)
|
|
return (0);
|
|
|
|
/*
|
|
* Store version information in array indexable by version index.
|
|
* Verify that object version requirements are satisfied along the
|
|
* way.
|
|
*/
|
|
obj->vernum = maxvernum + 1;
|
|
obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry));
|
|
|
|
vd = obj->verdef;
|
|
while (vd != NULL) {
|
|
if ((vd->vd_flags & VER_FLG_BASE) == 0) {
|
|
vernum = VER_DEF_IDX(vd->vd_ndx);
|
|
assert(vernum <= maxvernum);
|
|
vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
|
|
obj->vertab[vernum].hash = vd->vd_hash;
|
|
obj->vertab[vernum].name = obj->strtab + vda->vda_name;
|
|
obj->vertab[vernum].file = NULL;
|
|
obj->vertab[vernum].flags = 0;
|
|
}
|
|
if (vd->vd_next == 0)
|
|
break;
|
|
vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
|
|
}
|
|
|
|
vn = obj->verneed;
|
|
while (vn != NULL) {
|
|
depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
|
|
vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
|
|
for (;;) {
|
|
if (check_object_provided_version(obj, depobj, vna))
|
|
return (-1);
|
|
vernum = VER_NEED_IDX(vna->vna_other);
|
|
assert(vernum <= maxvernum);
|
|
obj->vertab[vernum].hash = vna->vna_hash;
|
|
obj->vertab[vernum].name = obj->strtab + vna->vna_name;
|
|
obj->vertab[vernum].file = obj->strtab + vn->vn_file;
|
|
obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
|
|
VER_INFO_HIDDEN : 0;
|
|
if (vna->vna_next == 0)
|
|
break;
|
|
vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
|
|
}
|
|
if (vn->vn_next == 0)
|
|
break;
|
|
vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
rtld_verify_versions(const Objlist *objlist)
|
|
{
|
|
Objlist_Entry *entry;
|
|
int rc;
|
|
|
|
rc = 0;
|
|
STAILQ_FOREACH(entry, objlist, link) {
|
|
/*
|
|
* Skip dummy objects or objects that have their version requirements
|
|
* already checked.
|
|
*/
|
|
if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
|
|
continue;
|
|
if (rtld_verify_object_versions(entry->obj) == -1) {
|
|
rc = -1;
|
|
if (ld_tracing == NULL)
|
|
break;
|
|
}
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
const Ver_Entry *
|
|
fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
|
|
{
|
|
Elf_Versym vernum;
|
|
|
|
if (obj->vertab) {
|
|
vernum = VER_NDX(obj->versyms[symnum]);
|
|
if (vernum >= obj->vernum) {
|
|
_rtld_error("%s: symbol %s has wrong verneed value %d",
|
|
obj->path, obj->strtab + symnum, vernum);
|
|
} else if (obj->vertab[vernum].hash != 0) {
|
|
return &obj->vertab[vernum];
|
|
}
|
|
}
|
|
return NULL;
|
|
}
|