freebsd-nq/libexec/rtld-aout/rtld.c

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1993-11-03 23:41:59 +00:00
/*
* Copyright (c) 1993 Paul Kranenburg
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Paul Kranenburg.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission
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*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
Changed the terminology for what used to be called the "memorizing" vector. Now it is called the "symbol caching" vector. This was made possible and unconfusing by other changes that allowed me to localize everything having to do with the caching vector in the function reloc_map(). Switched to alloca() for allocating the caching vector, and eliminated the special mmap-based allocation routines. Although this was motivated by performance reasons, it led to significant simplification of the code, and made it possible to confine the symbol caching code to the single function reloc_map(). Got rid of the unnecessary and inefficient division loop at the beginning of rtld(). Reduced the number of calls to getenv("LD_LIBRARY_PATH") to just 1, on suggestion from <davidg@root.com>. Added breaks out of the relocation loops when the relocation address is found to be 0. A relocation address of 0 is caused by an unused relocation entry. Unused relocation entries are caused by linking a shared object with the "-Bsymbolic" switch. The runtime linker itself is linked that way, and the last 40% of its relocation entries are unused. Thus, breaking out of the loop on the first such entry is a performance win when ld.so relocates itself. As a side benefit, it permits removing a test from md_relocate_simple() in ../i386/md-static-funcs.c. Unused relocation entries in other shared objects (linked with "-Bsymbolic") caused even bigger problems in previous versions of the runtime linker. The runtime linker interpreted the unused entries as if they were valid. That caused it to perform repeated relocations of the first byte of the shared object. In order to do that, it had to remap the text segment writable. Breaking out of the loop on the first unused relocation entry solves that. Submitted by: John Polstra <jdp@polstra.com>
1995-11-02 18:48:15 +00:00
* $Id: rtld.c,v 1.31 1995/10/27 22:01:00 jdp Exp $
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*/
#include <sys/param.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/errno.h>
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#include <sys/mman.h>
#ifndef MAP_COPY
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#define MAP_COPY MAP_PRIVATE
#endif
#include <err.h>
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#include <fcntl.h>
#include <a.out.h>
#include <stab.h>
#include <stdio.h>
#include <stdlib.h>
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#include <string.h>
#include <unistd.h>
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#if __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif
#include "ld.h"
#ifndef MAP_ANON
#define MAP_ANON 0
#define anon_open() do { \
if ((anon_fd = open("/dev/zero", O_RDWR, 0)) == -1) \
err("open: %s", "/dev/zero"); \
} while (0)
#define anon_close() do { \
(void)close(anon_fd); \
anon_fd = -1; \
} while (0)
#else
#define anon_open()
#define anon_close()
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#endif
/*
* Loader private data, hung off <so_map>->som_spd
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*/
struct somap_private {
int spd_version;
struct so_map *spd_parent;
int spd_refcount;
int spd_flags;
#define RTLD_MAIN 1
#define RTLD_RTLD 2
#define RTLD_DL 4
#define RTLD_INIT 8
unsigned long a_text; /* text size, if known */
unsigned long a_data; /* initialized data size */
unsigned long a_bss; /* uninitialized data size */
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#ifdef SUN_COMPAT
long spd_offset; /* Correction for Sun main programs */
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#endif
};
#define LM_PRIVATE(smp) ((struct somap_private *)(smp)->som_spd)
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#ifdef SUN_COMPAT
#define LM_OFFSET(smp) (LM_PRIVATE(smp)->spd_offset)
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#else
#define LM_OFFSET(smp) (0)
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#endif
/* Base address for section_dispatch_table entries */
#define LM_LDBASE(smp) (smp->som_addr + LM_OFFSET(smp))
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/* Start of text segment */
#define LM_TXTADDR(smp) (smp->som_addr == (caddr_t)0 ? PAGSIZ : 0)
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/* Start of run-time relocation_info */
#define LM_REL(smp) ((struct relocation_info *) \
(smp->som_addr + LM_OFFSET(smp) + LD_REL((smp)->som_dynamic)))
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/* Start of symbols */
#define LM_SYMBOL(smp, i) ((struct nzlist *) \
(smp->som_addr + LM_OFFSET(smp) + LD_SYMBOL((smp)->som_dynamic) + \
i * (LD_VERSION_NZLIST_P(smp->som_dynamic->d_version) ? \
sizeof(struct nzlist) : sizeof(struct nlist))))
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/* Start of hash table */
#define LM_HASH(smp) ((struct rrs_hash *) \
((smp)->som_addr + LM_OFFSET(smp) + LD_HASH((smp)->som_dynamic)))
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/* Start of strings */
#define LM_STRINGS(smp) ((char *) \
((smp)->som_addr + LM_OFFSET(smp) + LD_STRINGS((smp)->som_dynamic)))
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/* End of text */
#define LM_ETEXT(smp) ((char *) \
((smp)->som_addr + LM_TXTADDR(smp) + LD_TEXTSZ((smp)->som_dynamic)))
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/* Needed shared objects */
#define LM_NEED(smp) ((struct sod *) \
((smp)->som_addr + LM_TXTADDR(smp) + LD_NEED((smp)->som_dynamic)))
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/* PLT is in data segment, so don't use LM_OFFSET here */
#define LM_PLT(smp) ((jmpslot_t *) \
((smp)->som_addr + LD_PLT((smp)->som_dynamic)))
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/* Parent of link map */
#define LM_PARENT(smp) (LM_PRIVATE(smp)->spd_parent)
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char **environ;
char *__progname;
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int errno;
static uid_t uid, euid;
static gid_t gid, egid;
static int careful;
static char __main_progname[] = "main";
static char *main_progname = __main_progname;
static char us[] = "/usr/libexec/ld.so";
static int anon_fd = -1;
Changed the terminology for what used to be called the "memorizing" vector. Now it is called the "symbol caching" vector. This was made possible and unconfusing by other changes that allowed me to localize everything having to do with the caching vector in the function reloc_map(). Switched to alloca() for allocating the caching vector, and eliminated the special mmap-based allocation routines. Although this was motivated by performance reasons, it led to significant simplification of the code, and made it possible to confine the symbol caching code to the single function reloc_map(). Got rid of the unnecessary and inefficient division loop at the beginning of rtld(). Reduced the number of calls to getenv("LD_LIBRARY_PATH") to just 1, on suggestion from <davidg@root.com>. Added breaks out of the relocation loops when the relocation address is found to be 0. A relocation address of 0 is caused by an unused relocation entry. Unused relocation entries are caused by linking a shared object with the "-Bsymbolic" switch. The runtime linker itself is linked that way, and the last 40% of its relocation entries are unused. Thus, breaking out of the loop on the first such entry is a performance win when ld.so relocates itself. As a side benefit, it permits removing a test from md_relocate_simple() in ../i386/md-static-funcs.c. Unused relocation entries in other shared objects (linked with "-Bsymbolic") caused even bigger problems in previous versions of the runtime linker. The runtime linker interpreted the unused entries as if they were valid. That caused it to perform repeated relocations of the first byte of the shared object. In order to do that, it had to remap the text segment writable. Breaking out of the loop on the first unused relocation entry solves that. Submitted by: John Polstra <jdp@polstra.com>
1995-11-02 18:48:15 +00:00
static char *ld_library_path;
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struct so_map *link_map_head, *main_map;
struct so_map **link_map_tail = &link_map_head;
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struct rt_symbol *rt_symbol_head;
static void *__dlopen __P((char *, int));
static int __dlclose __P((void *));
static void *__dlsym __P((void *, char *));
static char *__dlerror __P((void));
static void __dlexit __P((void));
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static struct ld_entry ld_entry = {
__dlopen, __dlclose, __dlsym, __dlerror, __dlexit
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};
void xprintf __P((char *, ...));
static void load_objects __P(( struct crt_ldso *,
struct _dynamic *));
static struct so_map *map_object __P((struct sod *, struct so_map *));
static int unmap_object __P((struct so_map *));
static struct so_map *load_object __P((struct sod *, struct so_map *,
int, int));
static int unload_object __P((struct so_map *));
static struct so_map *alloc_link_map __P(( char *, struct sod *,
struct so_map *, caddr_t,
struct _dynamic *));
static inline int check_text_reloc __P(( struct relocation_info *,
struct so_map *,
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caddr_t));
static int reloc_map __P((struct so_map *));
static void reloc_copy __P((struct so_map *));
static void init_map __P((struct so_map *, char *, int));
static void call_map __P((struct so_map *, char *));
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static char *rtfindlib __P((char *, int, int, int *));
void binder_entry __P((void));
long binder __P((jmpslot_t *));
static struct nzlist *lookup __P((char *, struct so_map **, int));
static inline struct rt_symbol *lookup_rts __P((char *));
static struct rt_symbol *enter_rts __P((char *, long, int, caddr_t,
long, struct so_map *));
static void generror __P((char *, ...));
static void maphints __P((void));
static void unmaphints __P((void));
static int dl_cascade __P((struct so_map *));
static inline int
strcmp (register const char *s1, register const char *s2)
{
while (*s1 == *s2++)
if (*s1++ == 0)
return (0);
return (*(unsigned char *)s1 - *(unsigned char *)--s2);
}
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#include "md-static-funcs.c"
/*
* Called from assembler stub that has set up crtp (passed from crt0)
* and dp (our __DYNAMIC).
*/
int
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rtld(version, crtp, dp)
int version;
struct crt_ldso *crtp;
struct _dynamic *dp;
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{
struct relocation_info *reloc;
Changed the terminology for what used to be called the "memorizing" vector. Now it is called the "symbol caching" vector. This was made possible and unconfusing by other changes that allowed me to localize everything having to do with the caching vector in the function reloc_map(). Switched to alloca() for allocating the caching vector, and eliminated the special mmap-based allocation routines. Although this was motivated by performance reasons, it led to significant simplification of the code, and made it possible to confine the symbol caching code to the single function reloc_map(). Got rid of the unnecessary and inefficient division loop at the beginning of rtld(). Reduced the number of calls to getenv("LD_LIBRARY_PATH") to just 1, on suggestion from <davidg@root.com>. Added breaks out of the relocation loops when the relocation address is found to be 0. A relocation address of 0 is caused by an unused relocation entry. Unused relocation entries are caused by linking a shared object with the "-Bsymbolic" switch. The runtime linker itself is linked that way, and the last 40% of its relocation entries are unused. Thus, breaking out of the loop on the first such entry is a performance win when ld.so relocates itself. As a side benefit, it permits removing a test from md_relocate_simple() in ../i386/md-static-funcs.c. Unused relocation entries in other shared objects (linked with "-Bsymbolic") caused even bigger problems in previous versions of the runtime linker. The runtime linker interpreted the unused entries as if they were valid. That caused it to perform repeated relocations of the first byte of the shared object. In order to do that, it had to remap the text segment writable. Breaking out of the loop on the first unused relocation entry solves that. Submitted by: John Polstra <jdp@polstra.com>
1995-11-02 18:48:15 +00:00
struct relocation_info *reloc_limit; /* End+1 of relocation */
struct so_debug *ddp;
struct so_map *smp;
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/* Check version */
if (version != CRT_VERSION_BSD_2 &&
version != CRT_VERSION_BSD_3 &&
version != CRT_VERSION_SUN)
return -1;
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/* Fixup __DYNAMIC structure */
(long)dp->d_un.d_sdt += crtp->crt_ba;
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/* Relocate ourselves */
Changed the terminology for what used to be called the "memorizing" vector. Now it is called the "symbol caching" vector. This was made possible and unconfusing by other changes that allowed me to localize everything having to do with the caching vector in the function reloc_map(). Switched to alloca() for allocating the caching vector, and eliminated the special mmap-based allocation routines. Although this was motivated by performance reasons, it led to significant simplification of the code, and made it possible to confine the symbol caching code to the single function reloc_map(). Got rid of the unnecessary and inefficient division loop at the beginning of rtld(). Reduced the number of calls to getenv("LD_LIBRARY_PATH") to just 1, on suggestion from <davidg@root.com>. Added breaks out of the relocation loops when the relocation address is found to be 0. A relocation address of 0 is caused by an unused relocation entry. Unused relocation entries are caused by linking a shared object with the "-Bsymbolic" switch. The runtime linker itself is linked that way, and the last 40% of its relocation entries are unused. Thus, breaking out of the loop on the first such entry is a performance win when ld.so relocates itself. As a side benefit, it permits removing a test from md_relocate_simple() in ../i386/md-static-funcs.c. Unused relocation entries in other shared objects (linked with "-Bsymbolic") caused even bigger problems in previous versions of the runtime linker. The runtime linker interpreted the unused entries as if they were valid. That caused it to perform repeated relocations of the first byte of the shared object. In order to do that, it had to remap the text segment writable. Breaking out of the loop on the first unused relocation entry solves that. Submitted by: John Polstra <jdp@polstra.com>
1995-11-02 18:48:15 +00:00
reloc = (struct relocation_info *) (LD_REL(dp) + crtp->crt_ba);
reloc_limit =
(struct relocation_info *) ((char *) reloc + LD_RELSZ(dp));
while(reloc < reloc_limit) {
/*
* Objects linked with "-Bsymbolic" (in particular, ld.so
* itself) can end up having unused relocation entries at
* the end. These can be detected by the fact that they
* have an address of 0.
*/
if(reloc->r_address == 0) /* We're done */
break;
md_relocate_simple(reloc, crtp->crt_ba,
reloc->r_address + crtp->crt_ba);
++reloc;
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}
__progname = "ld.so";
if (version >= CRT_VERSION_BSD_3)
main_progname = crtp->crt_prog;
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/* Setup out (private) environ variable */
environ = crtp->crt_ep;
/* Get user and group identifiers */
uid = getuid(); euid = geteuid();
gid = getgid(); egid = getegid();
careful = (uid != euid) || (gid != egid);
if (careful) {
unsetenv("LD_LIBRARY_PATH");
unsetenv("LD_PRELOAD");
Changed the terminology for what used to be called the "memorizing" vector. Now it is called the "symbol caching" vector. This was made possible and unconfusing by other changes that allowed me to localize everything having to do with the caching vector in the function reloc_map(). Switched to alloca() for allocating the caching vector, and eliminated the special mmap-based allocation routines. Although this was motivated by performance reasons, it led to significant simplification of the code, and made it possible to confine the symbol caching code to the single function reloc_map(). Got rid of the unnecessary and inefficient division loop at the beginning of rtld(). Reduced the number of calls to getenv("LD_LIBRARY_PATH") to just 1, on suggestion from <davidg@root.com>. Added breaks out of the relocation loops when the relocation address is found to be 0. A relocation address of 0 is caused by an unused relocation entry. Unused relocation entries are caused by linking a shared object with the "-Bsymbolic" switch. The runtime linker itself is linked that way, and the last 40% of its relocation entries are unused. Thus, breaking out of the loop on the first such entry is a performance win when ld.so relocates itself. As a side benefit, it permits removing a test from md_relocate_simple() in ../i386/md-static-funcs.c. Unused relocation entries in other shared objects (linked with "-Bsymbolic") caused even bigger problems in previous versions of the runtime linker. The runtime linker interpreted the unused entries as if they were valid. That caused it to perform repeated relocations of the first byte of the shared object. In order to do that, it had to remap the text segment writable. Breaking out of the loop on the first unused relocation entry solves that. Submitted by: John Polstra <jdp@polstra.com>
1995-11-02 18:48:15 +00:00
} else
ld_library_path = getenv("LD_LIBRARY_PATH");
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/* Setup directory search */
Changed the terminology for what used to be called the "memorizing" vector. Now it is called the "symbol caching" vector. This was made possible and unconfusing by other changes that allowed me to localize everything having to do with the caching vector in the function reloc_map(). Switched to alloca() for allocating the caching vector, and eliminated the special mmap-based allocation routines. Although this was motivated by performance reasons, it led to significant simplification of the code, and made it possible to confine the symbol caching code to the single function reloc_map(). Got rid of the unnecessary and inefficient division loop at the beginning of rtld(). Reduced the number of calls to getenv("LD_LIBRARY_PATH") to just 1, on suggestion from <davidg@root.com>. Added breaks out of the relocation loops when the relocation address is found to be 0. A relocation address of 0 is caused by an unused relocation entry. Unused relocation entries are caused by linking a shared object with the "-Bsymbolic" switch. The runtime linker itself is linked that way, and the last 40% of its relocation entries are unused. Thus, breaking out of the loop on the first such entry is a performance win when ld.so relocates itself. As a side benefit, it permits removing a test from md_relocate_simple() in ../i386/md-static-funcs.c. Unused relocation entries in other shared objects (linked with "-Bsymbolic") caused even bigger problems in previous versions of the runtime linker. The runtime linker interpreted the unused entries as if they were valid. That caused it to perform repeated relocations of the first byte of the shared object. In order to do that, it had to remap the text segment writable. Breaking out of the loop on the first unused relocation entry solves that. Submitted by: John Polstra <jdp@polstra.com>
1995-11-02 18:48:15 +00:00
add_search_path(ld_library_path);
std_search_path();
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anon_open();
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/* Load required objects into the process address space */
load_objects(crtp, dp);
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/* Fill in some fields in main's __DYNAMIC structure */
crtp->crt_dp->d_entry = &ld_entry;
crtp->crt_dp->d_un.d_sdt->sdt_loaded = link_map_head->som_next;
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/* Relocate all loaded objects according to their RRS segments */
for (smp = link_map_head; smp; smp = smp->som_next) {
if (LM_PRIVATE(smp)->spd_flags & RTLD_RTLD)
continue;
if (reloc_map(smp) < 0)
return -1;
}
/* Copy any relocated initialized data. */
for (smp = link_map_head; smp; smp = smp->som_next) {
if (LM_PRIVATE(smp)->spd_flags & RTLD_RTLD)
continue;
reloc_copy(smp);
}
/* Call any object initialization routines. */
for (smp = link_map_head; smp; smp = smp->som_next) {
if (LM_PRIVATE(smp)->spd_flags & RTLD_RTLD)
continue;
init_map(smp, ".init", 0);
}
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ddp = crtp->crt_dp->d_debug;
ddp->dd_cc = rt_symbol_head;
if (ddp->dd_in_debugger) {
caddr_t addr = (caddr_t)((long)crtp->crt_bp & (~(PAGSIZ - 1)));
/* Set breakpoint for the benefit of debuggers */
if (mprotect(addr, PAGSIZ,
PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
err(1, "Cannot set breakpoint (%s)", main_progname);
}
md_set_breakpoint((long)crtp->crt_bp, (long *)&ddp->dd_bpt_shadow);
if (mprotect(addr, PAGSIZ, PROT_READ|PROT_EXEC) == -1) {
err(1, "Cannot re-protect breakpoint (%s)",
main_progname);
}
ddp->dd_bpt_addr = crtp->crt_bp;
if (link_map_head)
ddp->dd_sym_loaded = 1;
}
/* Close the hints file */
unmaphints();
/* Close our file descriptor */
(void)close(crtp->crt_ldfd);
anon_close();
return LDSO_VERSION_HAS_DLEXIT;
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}
static void
load_objects(crtp, dp)
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struct crt_ldso *crtp;
struct _dynamic *dp;
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{
struct so_map *smp;
int tracing = (int)getenv("LD_TRACE_LOADED_OBJECTS");
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/* Handle LD_PRELOAD's here */
/* Make an entry for the main program */
smp = alloc_link_map(main_progname, (struct sod *)0, (struct so_map *)0,
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(caddr_t)0, crtp->crt_dp);
LM_PRIVATE(smp)->spd_refcount++;
LM_PRIVATE(smp)->spd_flags |= RTLD_MAIN;
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/* Make an entry for ourselves */
smp = alloc_link_map(us, (struct sod *)0, (struct so_map *)0,
(caddr_t)crtp->crt_ba, dp);
LM_PRIVATE(smp)->spd_refcount++;
LM_PRIVATE(smp)->spd_flags |= RTLD_RTLD;
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for (smp = link_map_head; smp; smp = smp->som_next) {
struct sod *sodp;
long next = 0;
if (LM_PRIVATE(smp)->spd_flags & RTLD_RTLD)
continue;
if (smp->som_dynamic)
next = LD_NEED(smp->som_dynamic);
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while (next) {
struct so_map *newmap;
sodp = (struct sod *)(LM_LDBASE(smp) + next);
if ((newmap = map_object(sodp, smp)) == NULL) {
if (!tracing) {
errx(1, "%s: %s", main_progname,
__dlerror());
}
newmap = alloc_link_map(NULL, sodp, smp, 0, 0);
}
LM_PRIVATE(newmap)->spd_refcount++;
next = sodp->sod_next;
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}
}
if (! tracing)
return;
for (smp = link_map_head; smp; smp = smp->som_next) {
struct sod *sodp;
char *name, *path;
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if ((sodp = smp->som_sod) == NULL)
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continue;
name = sodp->sod_name + LM_LDBASE(LM_PARENT(smp));
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if ((path = smp->som_path) == NULL)
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path = "not found";
if (sodp->sod_library)
printf("\t-l%s.%d => %s (%p)\n", name,
sodp->sod_major, path, smp->som_addr);
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else
printf("\t%s => %s (%p)\n", name, path, smp->som_addr);
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}
exit(0);
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}
/*
* Allocate a new link map for shared object NAME loaded at ADDR as a
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* result of the presence of link object LOP in the link map PARENT.
*/
static struct so_map *
alloc_link_map(path, sodp, parent, addr, dp)
char *path;
struct sod *sodp;
struct so_map *parent;
caddr_t addr;
struct _dynamic *dp;
1993-11-03 23:41:59 +00:00
{
struct so_map *smp;
struct somap_private *smpp;
size_t smp_size;
/*
* Allocate so_map and private area with a single malloc. Round
* up the size of so_map so the private area is aligned.
*/
smp_size = ((((sizeof(struct so_map)) + sizeof (void *) - 1) /
sizeof (void *)) * sizeof (void *));
smp = (struct so_map *)xmalloc(smp_size +
sizeof (struct somap_private));
smpp = (struct somap_private *) (((caddr_t) smp) + smp_size);
smp->som_next = NULL;
*link_map_tail = smp;
link_map_tail = &smp->som_next;
1993-11-03 23:41:59 +00:00
smp->som_addr = addr;
if (path == NULL)
smp->som_path = NULL;
else
smp->som_path = strdup(path);
smp->som_sod = sodp;
smp->som_dynamic = dp;
smp->som_spd = (caddr_t)smpp;
1993-11-03 23:41:59 +00:00
/*XXX*/ if (addr == 0) main_map = smp;
1993-11-03 23:41:59 +00:00
smpp->spd_refcount = 0;
smpp->spd_flags = 0;
smpp->spd_parent = parent;
smpp->a_text = 0;
smpp->a_data = 0;
smpp->a_bss = 0;
1993-11-03 23:41:59 +00:00
#ifdef SUN_COMPAT
smpp->spd_offset =
(addr==0 && dp && dp->d_version==LD_VERSION_SUN) ? PAGSIZ : 0;
1993-11-03 23:41:59 +00:00
#endif
return smp;
1993-11-03 23:41:59 +00:00
}
static struct so_map *
find_object(sodp, smp)
struct sod *sodp;
struct so_map *smp;
{
char *path, *name = (char *)(sodp->sod_name + LM_LDBASE(smp));
int usehints = 0;
struct so_map *p;
if (sodp->sod_library) {
usehints = 1;
again:
path = rtfindlib(name, sodp->sod_major,
sodp->sod_minor, &usehints);
if (path == NULL) {
generror ("Can't find shared library \"%s\"",
name);
return NULL;
}
} else {
if (careful && *name != '/') {
generror ("Shared library path must start with \"/\" for \"%s\"",
name);
return NULL;
}
path = name;
}
/* Check if already loaded */
for (p = link_map_head; p; p = p->som_next)
if (p->som_path && strcmp(p->som_path, path) == 0)
break;
return p;
}
1993-11-03 23:41:59 +00:00
/*
* Map object identified by link object sodp which was found in link
* map smp. Returns a pointer to the link map for the requested object.
*
* On failure, it sets an error message that can be retrieved by __dlerror,
* and returns NULL.
1993-11-03 23:41:59 +00:00
*/
static struct so_map *
map_object(sodp, smp)
struct sod *sodp;
struct so_map *smp;
1993-11-03 23:41:59 +00:00
{
struct _dynamic *dp;
char *path, *name = (char *)(sodp->sod_name + LM_LDBASE(smp));
1993-11-03 23:41:59 +00:00
int fd;
caddr_t addr;
struct exec hdr;
int usehints = 0;
struct so_map *p;
struct somap_private *smpp;
1993-11-03 23:41:59 +00:00
if (sodp->sod_library) {
1993-11-03 23:41:59 +00:00
usehints = 1;
again:
path = rtfindlib(name, sodp->sod_major,
sodp->sod_minor, &usehints);
if (path == NULL) {
generror ("Can't find shared library"
" \"lib%s.so.%d.%d\"",
name, sodp->sod_major, sodp->sod_minor);
return NULL;
}
1993-11-03 23:41:59 +00:00
} else {
if (careful && *name != '/') {
generror ("Shared library path must start with \"/\" for \"%s\"",
name);
return NULL;
}
1993-11-03 23:41:59 +00:00
path = name;
}
/* Check if already loaded */
for (p = link_map_head; p; p = p->som_next)
if (p->som_path && strcmp(p->som_path, path) == 0)
break;
if (p != NULL)
return p;
if ((fd = open(path, O_RDONLY, 0)) == -1) {
1993-11-03 23:41:59 +00:00
if (usehints) {
usehints = 0;
goto again;
}
generror ("open failed for \"%s\" : %s",
path, strerror (errno));
return NULL;
1993-11-03 23:41:59 +00:00
}
if (read(fd, &hdr, sizeof(hdr)) != sizeof(hdr)) {
generror ("header read failed for \"%s\"", path);
(void)close(fd);
return NULL;
1993-11-03 23:41:59 +00:00
}
if (N_BADMAG(hdr)) {
generror ("bad magic number in \"%s\"", path);
(void)close(fd);
return NULL;
}
1993-11-03 23:41:59 +00:00
if ((addr = mmap(0, hdr.a_text + hdr.a_data + hdr.a_bss,
PROT_READ|PROT_EXEC,
MAP_COPY, fd, 0)) == (caddr_t)-1) {
generror ("mmap failed for \"%s\" : %s",
path, strerror (errno));
(void)close(fd);
return NULL;
}
1993-11-03 23:41:59 +00:00
if (mprotect(addr + hdr.a_text, hdr.a_data,
PROT_READ|PROT_WRITE|PROT_EXEC) != 0) {
generror ("mprotect failed for \"%s\" : %s",
path, strerror (errno));
(void)close(fd);
return NULL;
}
1993-11-03 23:41:59 +00:00
if (mmap(addr + hdr.a_text + hdr.a_data, hdr.a_bss,
PROT_READ|PROT_WRITE|PROT_EXEC,
MAP_ANON|MAP_COPY|MAP_FIXED,
anon_fd, 0) == (caddr_t)-1) {
generror ("mmap failed for \"%s\" : %s",
path, strerror (errno));
(void)close(fd);
return NULL;
}
1993-11-03 23:41:59 +00:00
(void)close(fd);
1993-11-03 23:41:59 +00:00
/* Assume _DYNAMIC is the first data item */
dp = (struct _dynamic *)(addr+hdr.a_text);
1993-11-03 23:41:59 +00:00
/* Fixup __DYNAMIC structure */
(long)dp->d_un.d_sdt += (long)addr;
1993-11-03 23:41:59 +00:00
p = alloc_link_map(path, sodp, smp, addr, dp);
1995-05-30 05:05:38 +00:00
/* save segment sizes for unmap. */
smpp = LM_PRIVATE(p);
smpp->a_text = hdr.a_text;
smpp->a_data = hdr.a_data;
smpp->a_bss = hdr.a_bss;
return p;
}
/*
* Unmap an object that is nolonger in use.
*/
static int
unmap_object(smp)
struct so_map *smp;
{
struct so_map *prev, *p;
struct somap_private *smpp;
/* Find the object in the list and unlink it */
for (prev = NULL, p = link_map_head;
1995-05-30 05:05:38 +00:00
p != smp;
prev = p, p = p->som_next) continue;
if (prev == NULL) {
link_map_head = smp->som_next;
if (smp->som_next == NULL)
link_map_tail = &link_map_head;
} else {
prev->som_next = smp->som_next;
if (smp->som_next == NULL)
link_map_tail = &prev->som_next;
}
/* Unmap the sections we have mapped */
smpp = LM_PRIVATE(smp);
if (munmap(smp->som_addr, smpp->a_text + smpp->a_data) < 0) {
generror ("munmap failed: %s", strerror (errno));
return -1;
}
if (smpp->a_bss > 0) {
if (munmap(smp->som_addr + smpp->a_text + smpp->a_data,
smpp->a_bss) < 0) {
generror ("munmap failed: %s", strerror (errno));
return -1;
}
}
if (smp->som_path) free(smp->som_path);
free(smp);
return 0;
1993-11-03 23:41:59 +00:00
}
static inline int
check_text_reloc(r, smp, addr)
struct relocation_info *r;
struct so_map *smp;
caddr_t addr;
1993-11-03 23:41:59 +00:00
{
char *sym;
1993-11-03 23:41:59 +00:00
if (addr >= LM_ETEXT(smp))
return 0;
1993-11-03 23:41:59 +00:00
if (RELOC_EXTERN_P(r))
sym = LM_STRINGS(smp) +
LM_SYMBOL(smp, RELOC_SYMBOL(r))->nz_strx;
else
sym = "";
1993-11-03 23:41:59 +00:00
if (getenv("LD_SUPPRESS_WARNINGS") == NULL &&
getenv("LD_WARN_NON_PURE_CODE") != NULL)
warnx("warning: non pure code in %s at %x (%s)",
smp->som_path, r->r_address, sym);
if (smp->som_write == 0 &&
mprotect(smp->som_addr + LM_TXTADDR(smp),
LD_TEXTSZ(smp->som_dynamic),
PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
generror ("mprotect failed for \"%s\" : %s",
smp->som_path, strerror (errno));
return -1;
}
1993-11-03 23:41:59 +00:00
smp->som_write = 1;
return 0;
}
1993-11-03 23:41:59 +00:00
static int
reloc_map(smp)
struct so_map *smp;
{
Changed the terminology for what used to be called the "memorizing" vector. Now it is called the "symbol caching" vector. This was made possible and unconfusing by other changes that allowed me to localize everything having to do with the caching vector in the function reloc_map(). Switched to alloca() for allocating the caching vector, and eliminated the special mmap-based allocation routines. Although this was motivated by performance reasons, it led to significant simplification of the code, and made it possible to confine the symbol caching code to the single function reloc_map(). Got rid of the unnecessary and inefficient division loop at the beginning of rtld(). Reduced the number of calls to getenv("LD_LIBRARY_PATH") to just 1, on suggestion from <davidg@root.com>. Added breaks out of the relocation loops when the relocation address is found to be 0. A relocation address of 0 is caused by an unused relocation entry. Unused relocation entries are caused by linking a shared object with the "-Bsymbolic" switch. The runtime linker itself is linked that way, and the last 40% of its relocation entries are unused. Thus, breaking out of the loop on the first such entry is a performance win when ld.so relocates itself. As a side benefit, it permits removing a test from md_relocate_simple() in ../i386/md-static-funcs.c. Unused relocation entries in other shared objects (linked with "-Bsymbolic") caused even bigger problems in previous versions of the runtime linker. The runtime linker interpreted the unused entries as if they were valid. That caused it to perform repeated relocations of the first byte of the shared object. In order to do that, it had to remap the text segment writable. Breaking out of the loop on the first unused relocation entry solves that. Submitted by: John Polstra <jdp@polstra.com>
1995-11-02 18:48:15 +00:00
/*
* Caching structure for reducing the number of calls to
* lookup() during relocation.
*
* While relocating a given shared object, the dynamic linker
* maintains a caching vector that is directly indexed by
* the symbol number in the relocation entry. The first time
* a given symbol is looked up, the caching vector is
* filled in with a pointer to the symbol table entry, and
* a pointer to the so_map of the shared object in which the
* symbol was defined. On subsequent uses of the same symbol,
* that information is retrieved directly from the caching
* vector, without calling lookup() again.
*
* A symbol that is referenced in a relocation entry is
* typically referenced in many relocation entries, so this
* caching reduces the number of calls to lookup()
* dramatically. The overall improvement in the speed of
* dynamic linking is also dramatic -- as much as a factor
* of three for programs that use many shared libaries.
*/
struct cacheent {
struct nzlist *np; /* Pointer to symbol entry */
struct so_map *src_map; /* Shared object that defined symbol */
};
struct _dynamic *dp = smp->som_dynamic;
struct relocation_info *r = LM_REL(smp);
struct relocation_info *rend = r + LD_RELSZ(dp)/sizeof(*r);
long symbolbase = (long)LM_SYMBOL(smp, 0);
char *stringbase = LM_STRINGS(smp);
int symsize = LD_VERSION_NZLIST_P(dp->d_version) ?
sizeof(struct nzlist) :
sizeof(struct nlist);
Changed the terminology for what used to be called the "memorizing" vector. Now it is called the "symbol caching" vector. This was made possible and unconfusing by other changes that allowed me to localize everything having to do with the caching vector in the function reloc_map(). Switched to alloca() for allocating the caching vector, and eliminated the special mmap-based allocation routines. Although this was motivated by performance reasons, it led to significant simplification of the code, and made it possible to confine the symbol caching code to the single function reloc_map(). Got rid of the unnecessary and inefficient division loop at the beginning of rtld(). Reduced the number of calls to getenv("LD_LIBRARY_PATH") to just 1, on suggestion from <davidg@root.com>. Added breaks out of the relocation loops when the relocation address is found to be 0. A relocation address of 0 is caused by an unused relocation entry. Unused relocation entries are caused by linking a shared object with the "-Bsymbolic" switch. The runtime linker itself is linked that way, and the last 40% of its relocation entries are unused. Thus, breaking out of the loop on the first such entry is a performance win when ld.so relocates itself. As a side benefit, it permits removing a test from md_relocate_simple() in ../i386/md-static-funcs.c. Unused relocation entries in other shared objects (linked with "-Bsymbolic") caused even bigger problems in previous versions of the runtime linker. The runtime linker interpreted the unused entries as if they were valid. That caused it to perform repeated relocations of the first byte of the shared object. In order to do that, it had to remap the text segment writable. Breaking out of the loop on the first unused relocation entry solves that. Submitted by: John Polstra <jdp@polstra.com>
1995-11-02 18:48:15 +00:00
long numsyms = LD_STABSZ(dp) / symsize;
size_t cachebytes = numsyms * sizeof(struct cacheent);
struct cacheent *symcache =
(struct cacheent *) alloca(cachebytes);
if(symcache == NULL) {
generror("Cannot allocate symbol caching vector for %s",
smp->som_path);
return -1;
}
Changed the terminology for what used to be called the "memorizing" vector. Now it is called the "symbol caching" vector. This was made possible and unconfusing by other changes that allowed me to localize everything having to do with the caching vector in the function reloc_map(). Switched to alloca() for allocating the caching vector, and eliminated the special mmap-based allocation routines. Although this was motivated by performance reasons, it led to significant simplification of the code, and made it possible to confine the symbol caching code to the single function reloc_map(). Got rid of the unnecessary and inefficient division loop at the beginning of rtld(). Reduced the number of calls to getenv("LD_LIBRARY_PATH") to just 1, on suggestion from <davidg@root.com>. Added breaks out of the relocation loops when the relocation address is found to be 0. A relocation address of 0 is caused by an unused relocation entry. Unused relocation entries are caused by linking a shared object with the "-Bsymbolic" switch. The runtime linker itself is linked that way, and the last 40% of its relocation entries are unused. Thus, breaking out of the loop on the first such entry is a performance win when ld.so relocates itself. As a side benefit, it permits removing a test from md_relocate_simple() in ../i386/md-static-funcs.c. Unused relocation entries in other shared objects (linked with "-Bsymbolic") caused even bigger problems in previous versions of the runtime linker. The runtime linker interpreted the unused entries as if they were valid. That caused it to perform repeated relocations of the first byte of the shared object. In order to do that, it had to remap the text segment writable. Breaking out of the loop on the first unused relocation entry solves that. Submitted by: John Polstra <jdp@polstra.com>
1995-11-02 18:48:15 +00:00
bzero(symcache, cachebytes);
if (LD_PLTSZ(dp))
md_fix_jmpslot(LM_PLT(smp),
(long)LM_PLT(smp), (long)binder_entry);
for (; r < rend; r++) {
char *sym;
Changed the terminology for what used to be called the "memorizing" vector. Now it is called the "symbol caching" vector. This was made possible and unconfusing by other changes that allowed me to localize everything having to do with the caching vector in the function reloc_map(). Switched to alloca() for allocating the caching vector, and eliminated the special mmap-based allocation routines. Although this was motivated by performance reasons, it led to significant simplification of the code, and made it possible to confine the symbol caching code to the single function reloc_map(). Got rid of the unnecessary and inefficient division loop at the beginning of rtld(). Reduced the number of calls to getenv("LD_LIBRARY_PATH") to just 1, on suggestion from <davidg@root.com>. Added breaks out of the relocation loops when the relocation address is found to be 0. A relocation address of 0 is caused by an unused relocation entry. Unused relocation entries are caused by linking a shared object with the "-Bsymbolic" switch. The runtime linker itself is linked that way, and the last 40% of its relocation entries are unused. Thus, breaking out of the loop on the first such entry is a performance win when ld.so relocates itself. As a side benefit, it permits removing a test from md_relocate_simple() in ../i386/md-static-funcs.c. Unused relocation entries in other shared objects (linked with "-Bsymbolic") caused even bigger problems in previous versions of the runtime linker. The runtime linker interpreted the unused entries as if they were valid. That caused it to perform repeated relocations of the first byte of the shared object. In order to do that, it had to remap the text segment writable. Breaking out of the loop on the first unused relocation entry solves that. Submitted by: John Polstra <jdp@polstra.com>
1995-11-02 18:48:15 +00:00
caddr_t addr;
Changed the terminology for what used to be called the "memorizing" vector. Now it is called the "symbol caching" vector. This was made possible and unconfusing by other changes that allowed me to localize everything having to do with the caching vector in the function reloc_map(). Switched to alloca() for allocating the caching vector, and eliminated the special mmap-based allocation routines. Although this was motivated by performance reasons, it led to significant simplification of the code, and made it possible to confine the symbol caching code to the single function reloc_map(). Got rid of the unnecessary and inefficient division loop at the beginning of rtld(). Reduced the number of calls to getenv("LD_LIBRARY_PATH") to just 1, on suggestion from <davidg@root.com>. Added breaks out of the relocation loops when the relocation address is found to be 0. A relocation address of 0 is caused by an unused relocation entry. Unused relocation entries are caused by linking a shared object with the "-Bsymbolic" switch. The runtime linker itself is linked that way, and the last 40% of its relocation entries are unused. Thus, breaking out of the loop on the first such entry is a performance win when ld.so relocates itself. As a side benefit, it permits removing a test from md_relocate_simple() in ../i386/md-static-funcs.c. Unused relocation entries in other shared objects (linked with "-Bsymbolic") caused even bigger problems in previous versions of the runtime linker. The runtime linker interpreted the unused entries as if they were valid. That caused it to perform repeated relocations of the first byte of the shared object. In order to do that, it had to remap the text segment writable. Breaking out of the loop on the first unused relocation entry solves that. Submitted by: John Polstra <jdp@polstra.com>
1995-11-02 18:48:15 +00:00
/*
* Objects linked with "-Bsymbolic" can end up having unused
* relocation entries at the end. These can be detected by
* the fact that they have an address of 0.
*/
if(r->r_address == 0) /* Finished relocating this object */
break;
addr = smp->som_addr + r->r_address;
if (check_text_reloc(r, smp, addr) < 0)
return -1;
if (RELOC_EXTERN_P(r)) {
struct so_map *src_map = NULL;
struct nzlist *p, *np;
long relocation;
if (RELOC_LAZY_P(r))
continue;
1993-11-03 23:41:59 +00:00
p = (struct nzlist *)
(symbolbase + symsize * RELOC_SYMBOL(r));
if (p->nz_type == (N_SETV + N_EXT))
src_map = smp;
sym = stringbase + p->nz_strx;
Changed the terminology for what used to be called the "memorizing" vector. Now it is called the "symbol caching" vector. This was made possible and unconfusing by other changes that allowed me to localize everything having to do with the caching vector in the function reloc_map(). Switched to alloca() for allocating the caching vector, and eliminated the special mmap-based allocation routines. Although this was motivated by performance reasons, it led to significant simplification of the code, and made it possible to confine the symbol caching code to the single function reloc_map(). Got rid of the unnecessary and inefficient division loop at the beginning of rtld(). Reduced the number of calls to getenv("LD_LIBRARY_PATH") to just 1, on suggestion from <davidg@root.com>. Added breaks out of the relocation loops when the relocation address is found to be 0. A relocation address of 0 is caused by an unused relocation entry. Unused relocation entries are caused by linking a shared object with the "-Bsymbolic" switch. The runtime linker itself is linked that way, and the last 40% of its relocation entries are unused. Thus, breaking out of the loop on the first such entry is a performance win when ld.so relocates itself. As a side benefit, it permits removing a test from md_relocate_simple() in ../i386/md-static-funcs.c. Unused relocation entries in other shared objects (linked with "-Bsymbolic") caused even bigger problems in previous versions of the runtime linker. The runtime linker interpreted the unused entries as if they were valid. That caused it to perform repeated relocations of the first byte of the shared object. In order to do that, it had to remap the text segment writable. Breaking out of the loop on the first unused relocation entry solves that. Submitted by: John Polstra <jdp@polstra.com>
1995-11-02 18:48:15 +00:00
/*
* Look up the symbol, checking the caching
* vector first.
*/
np = symcache[RELOC_SYMBOL(r)].np;
if(np != NULL) /* Symbol already cached */
src_map = symcache[RELOC_SYMBOL(r)].src_map;
else { /* Symbol not cached yet */
np = lookup(sym, &src_map, 0/*XXX-jumpslots!*/);
Changed the terminology for what used to be called the "memorizing" vector. Now it is called the "symbol caching" vector. This was made possible and unconfusing by other changes that allowed me to localize everything having to do with the caching vector in the function reloc_map(). Switched to alloca() for allocating the caching vector, and eliminated the special mmap-based allocation routines. Although this was motivated by performance reasons, it led to significant simplification of the code, and made it possible to confine the symbol caching code to the single function reloc_map(). Got rid of the unnecessary and inefficient division loop at the beginning of rtld(). Reduced the number of calls to getenv("LD_LIBRARY_PATH") to just 1, on suggestion from <davidg@root.com>. Added breaks out of the relocation loops when the relocation address is found to be 0. A relocation address of 0 is caused by an unused relocation entry. Unused relocation entries are caused by linking a shared object with the "-Bsymbolic" switch. The runtime linker itself is linked that way, and the last 40% of its relocation entries are unused. Thus, breaking out of the loop on the first such entry is a performance win when ld.so relocates itself. As a side benefit, it permits removing a test from md_relocate_simple() in ../i386/md-static-funcs.c. Unused relocation entries in other shared objects (linked with "-Bsymbolic") caused even bigger problems in previous versions of the runtime linker. The runtime linker interpreted the unused entries as if they were valid. That caused it to perform repeated relocations of the first byte of the shared object. In order to do that, it had to remap the text segment writable. Breaking out of the loop on the first unused relocation entry solves that. Submitted by: John Polstra <jdp@polstra.com>
1995-11-02 18:48:15 +00:00
/*
* Record the needed information about
* the symbol in the caching vector,
* so that we won't have to call
* lookup the next time we encounter
* the symbol.
*/
symcache[RELOC_SYMBOL(r)].np = np;
symcache[RELOC_SYMBOL(r)].src_map = src_map;
}
if (np == NULL) {
generror ("Undefined symbol \"%s\" in %s:%s",
sym, main_progname, smp->som_path);
return -1;
}
Changed the terminology for what used to be called the "memorizing" vector. Now it is called the "symbol caching" vector. This was made possible and unconfusing by other changes that allowed me to localize everything having to do with the caching vector in the function reloc_map(). Switched to alloca() for allocating the caching vector, and eliminated the special mmap-based allocation routines. Although this was motivated by performance reasons, it led to significant simplification of the code, and made it possible to confine the symbol caching code to the single function reloc_map(). Got rid of the unnecessary and inefficient division loop at the beginning of rtld(). Reduced the number of calls to getenv("LD_LIBRARY_PATH") to just 1, on suggestion from <davidg@root.com>. Added breaks out of the relocation loops when the relocation address is found to be 0. A relocation address of 0 is caused by an unused relocation entry. Unused relocation entries are caused by linking a shared object with the "-Bsymbolic" switch. The runtime linker itself is linked that way, and the last 40% of its relocation entries are unused. Thus, breaking out of the loop on the first such entry is a performance win when ld.so relocates itself. As a side benefit, it permits removing a test from md_relocate_simple() in ../i386/md-static-funcs.c. Unused relocation entries in other shared objects (linked with "-Bsymbolic") caused even bigger problems in previous versions of the runtime linker. The runtime linker interpreted the unused entries as if they were valid. That caused it to perform repeated relocations of the first byte of the shared object. In order to do that, it had to remap the text segment writable. Breaking out of the loop on the first unused relocation entry solves that. Submitted by: John Polstra <jdp@polstra.com>
1995-11-02 18:48:15 +00:00
/*
* Found symbol definition.
* If it's in a link map, adjust value
* according to the load address of that map.
* Otherwise it's a run-time allocated common
* whose value is already up-to-date.
*/
relocation = md_get_addend(r, addr);
relocation += np->nz_value;
if (src_map)
relocation += (long)src_map->som_addr;
if (RELOC_PCREL_P(r))
relocation -= (long)smp->som_addr;
if (RELOC_COPY_P(r) && src_map) {
(void)enter_rts(sym,
(long)addr,
N_DATA + N_EXT,
src_map->som_addr + np->nz_value,
np->nz_size, src_map);
continue;
}
md_relocate(r, relocation, addr, 0);
1993-11-03 23:41:59 +00:00
} else {
md_relocate(r,
1993-11-03 23:41:59 +00:00
#ifdef SUN_COMPAT
md_get_rt_segment_addend(r, addr)
1993-11-03 23:41:59 +00:00
#else
md_get_addend(r, addr)
1993-11-03 23:41:59 +00:00
#endif
+ (long)smp->som_addr, addr, 0);
1993-11-03 23:41:59 +00:00
}
}
if (smp->som_write) {
if (mprotect(smp->som_addr + LM_TXTADDR(smp),
LD_TEXTSZ(smp->som_dynamic),
PROT_READ|PROT_EXEC) == -1) {
generror ("mprotect failed for \"%s\" : %s",
smp->som_path, strerror (errno));
return -1;
}
smp->som_write = 0;
1993-11-03 23:41:59 +00:00
}
return 0;
1993-11-03 23:41:59 +00:00
}
static void
reloc_copy(smp)
struct so_map *smp;
1993-11-03 23:41:59 +00:00
{
struct rt_symbol *rtsp;
for (rtsp = rt_symbol_head; rtsp; rtsp = rtsp->rt_next)
if ((rtsp->rt_smp == NULL || rtsp->rt_smp == smp) &&
rtsp->rt_sp->nz_type == N_DATA + N_EXT) {
1993-11-03 23:41:59 +00:00
bcopy(rtsp->rt_srcaddr, (caddr_t)rtsp->rt_sp->nz_value,
rtsp->rt_sp->nz_size);
}
}
static void
init_map(smp, sym, dependants)
struct so_map *smp;
char *sym;
int dependants;
{
struct so_map *src_map = smp;
struct nzlist *np;
if (LM_PRIVATE(smp)->spd_flags & RTLD_INIT)
return;
LM_PRIVATE(smp)->spd_flags |= RTLD_INIT;
if (dependants) {
struct sod *sodp;
struct so_map *smp2;
long next;
next = LD_NEED(smp->som_dynamic);
while (next) {
sodp = (struct sod *)(LM_LDBASE(smp) + next);
smp2 = find_object(sodp, smp);
if (smp2)
init_map(smp2, sym, dependants);
next = sodp->sod_next;
}
}
np = lookup(sym, &src_map, 1);
if (np)
(*(void (*)())(src_map->som_addr + np->nz_value))();
}
static void
call_map(smp, sym)
struct so_map *smp;
char *sym;
1993-11-03 23:41:59 +00:00
{
struct so_map *src_map = smp;
struct nzlist *np;
1993-11-03 23:41:59 +00:00
np = lookup(sym, &src_map, 1);
if (np)
(*(void (*)())(src_map->som_addr + np->nz_value))();
}
1993-11-03 23:41:59 +00:00
/*
* Load an object with all its dependant objects, recording the type of the
* object and optionally calling its init function.
*/
static struct so_map *
load_object(sodp, parent, type, init)
struct sod *sodp;
struct so_map *parent;
int type;
int init;
{
struct so_map* smp;
/*
* Find or map the object.
*/
smp = map_object(sodp, parent);
if (smp == NULL) return NULL;
/*
* The first time the object is mapped, load it's dependant objects and
* relocate it.
*/
if (LM_PRIVATE(smp)->spd_refcount++ == 0) {
struct sod *sodp;
struct so_map *smp2;
long next;
next = LD_NEED(smp->som_dynamic);
/*
* Load dependant objects but defer initialisation until later.
* When all the dependants (and sub dependants, etc.) have been
* loaded and relocated, it is safe to call the init functions,
* using a recursive call to init_map. This ensures that if init
* code in the dependants calls code in the parent, it will work
* as expected.
*/
while (next) {
sodp = (struct sod *)(LM_LDBASE(smp) + next);
/*
* Dependant objects (of both dlopen and main) don't get a
* specific type.
*/
if ((smp2 = load_object(sodp, smp, 0, 0)) == NULL) {
#ifdef DEBUG
xprintf("ld.so: map_object failed on cascaded %s %s (%d.%d): %s\n",
smp->sod_library ? "library" : "file", smp->sod_name,
smp->sod_major, smp->sod_minor, strerror(errno));
#endif
unload_object(smp);
return NULL;
}
next = sodp->sod_next;
}
LM_PRIVATE(smp)->spd_flags |= type;
if (reloc_map(smp) < 0) {
unload_object(smp);
return NULL;
}
reloc_copy(smp);
if (init) {
init_map(smp, ".init", 1);
}
}
return smp;
}
/*
* Unload an object, recursively unloading dependant objects.
*/
static int
unload_object(smp)
struct so_map *smp;
{
struct so_map *smp2;
struct sod *sodp;
long next;
if (--LM_PRIVATE(smp)->spd_refcount != 0)
return -1;
/*
* Call destructors for the object (before unloading its dependants
* since destructors may use them. Only call destructors if constructors
* have been called.
*/
if (LM_PRIVATE(smp)->spd_flags & RTLD_INIT)
call_map(smp, ".fini");
/*
* Unmap any dependant objects first.
*/
next = LD_NEED(smp->som_dynamic);
while (next) {
sodp = (struct sod *)(LM_LDBASE(smp) + next);
smp2 = find_object(sodp, smp);
if (smp2)
unload_object(smp2);
next = sodp->sod_next;
}
/*
* Remove from address space.
*/
if (unmap_object(smp) < 0)
return -1;
return 0;
}
/*
* Run-time common symbol table.
*/
1993-11-03 23:41:59 +00:00
#define RTC_TABSIZE 57
static struct rt_symbol *rt_symtab[RTC_TABSIZE];
1993-11-03 23:41:59 +00:00
/*
* Compute hash value for run-time symbol table
*/
static inline int
hash_string(key)
char *key;
{
register char *cp;
register int k;
1993-11-03 23:41:59 +00:00
cp = key;
k = 0;
while (*cp)
k = (((k << 1) + (k >> 14)) ^ (*cp++)) & 0x3fff;
1993-11-03 23:41:59 +00:00
return k;
1993-11-03 23:41:59 +00:00
}
/*
* Lookup KEY in the run-time common symbol table.
*/
static inline struct rt_symbol *
lookup_rts(key)
char *key;
{
register int hashval;
register struct rt_symbol *rtsp;
/* Determine which bucket. */
hashval = hash_string(key) % RTC_TABSIZE;
/* Search the bucket. */
for (rtsp = rt_symtab[hashval]; rtsp; rtsp = rtsp->rt_link)
if (strcmp(key, rtsp->rt_sp->nz_name) == 0)
return rtsp;
return NULL;
}
static struct rt_symbol *
enter_rts(name, value, type, srcaddr, size, smp)
char *name;
long value;
int type;
caddr_t srcaddr;
long size;
struct so_map *smp;
{
register int hashval;
register struct rt_symbol *rtsp, **rpp;
/* Determine which bucket */
hashval = hash_string(name) % RTC_TABSIZE;
/* Find end of bucket */
for (rpp = &rt_symtab[hashval]; *rpp; rpp = &(*rpp)->rt_link)
continue;
/* Allocate new common symbol */
rtsp = (struct rt_symbol *)malloc(sizeof(struct rt_symbol));
rtsp->rt_sp = (struct nzlist *)malloc(sizeof(struct nzlist));
rtsp->rt_sp->nz_name = strdup(name);
rtsp->rt_sp->nz_value = value;
rtsp->rt_sp->nz_type = type;
rtsp->rt_sp->nz_size = size;
rtsp->rt_srcaddr = srcaddr;
rtsp->rt_smp = smp;
rtsp->rt_link = NULL;
/* Link onto linear list as well */
rtsp->rt_next = rt_symbol_head;
rt_symbol_head = rtsp;
*rpp = rtsp;
return rtsp;
}
/*
* Lookup NAME in the link maps. The link map producing a definition
* is returned in SRC_MAP. If SRC_MAP is not NULL on entry the search is
* confined to that map. If STRONG is set, the symbol returned must
* have a proper type (used by binder()).
*/
static struct nzlist *
lookup(name, src_map, strong)
char *name;
struct so_map **src_map; /* IN/OUT */
int strong;
1993-11-03 23:41:59 +00:00
{
long common_size = 0;
struct so_map *smp;
1993-11-03 23:41:59 +00:00
struct rt_symbol *rtsp;
if ((rtsp = lookup_rts(name)) != NULL)
return rtsp->rt_sp;
/*
* Search all maps for a definition of NAME
*/
for (smp = link_map_head; smp; smp = smp->som_next) {
int buckets;
long hashval;
1993-11-03 23:41:59 +00:00
struct rrs_hash *hp;
char *cp;
struct nzlist *np;
/* Some local caching */
long symbolbase;
struct rrs_hash *hashbase;
char *stringbase;
int symsize;
if (*src_map && smp != *src_map)
continue;
if ((buckets = LD_BUCKETS(smp->som_dynamic)) == 0)
1995-05-30 05:05:38 +00:00
continue;
if (LM_PRIVATE(smp)->spd_flags & RTLD_RTLD)
continue;
restart:
1993-11-03 23:41:59 +00:00
/*
* Compute bucket in which the symbol might be found.
*/
for (hashval = 0, cp = name; *cp; cp++)
1993-11-03 23:41:59 +00:00
hashval = (hashval << 1) + *cp;
hashval = (hashval & 0x7fffffff) % buckets;
hashbase = LM_HASH(smp);
hp = hashbase + hashval;
1993-11-03 23:41:59 +00:00
if (hp->rh_symbolnum == -1)
/* Nothing in this bucket */
continue;
symbolbase = (long)LM_SYMBOL(smp, 0);
stringbase = LM_STRINGS(smp);
symsize = LD_VERSION_NZLIST_P(smp->som_dynamic->d_version)?
sizeof(struct nzlist) :
sizeof(struct nlist);
1993-11-03 23:41:59 +00:00
while (hp) {
np = (struct nzlist *)
(symbolbase + hp->rh_symbolnum * symsize);
cp = stringbase + np->nz_strx;
1993-11-03 23:41:59 +00:00
if (strcmp(cp, name) == 0)
break;
if (hp->rh_next == 0)
hp = NULL;
else
hp = hashbase + hp->rh_next;
1993-11-03 23:41:59 +00:00
}
if (hp == NULL)
/* Nothing in this bucket */
continue;
/*
* We have a symbol with the name we're looking for.
*/
if (np->nz_type == N_INDR+N_EXT) {
/*
* Next symbol gives the aliased name. Restart
* search with new name and confine to this map.
*/
name = stringbase + (++np)->nz_strx;
*src_map = smp;
goto restart;
}
1993-11-03 23:41:59 +00:00
if (np->nz_value == 0)
/* It's not a definition */
continue;
if (np->nz_type == N_UNDF+N_EXT && np->nz_value != 0) {
if (np->nz_other == AUX_FUNC) {
/* It's a weak function definition */
if (strong)
continue;
} else {
/* It's a common, note value and continue search */
if (common_size < np->nz_value)
common_size = np->nz_value;
continue;
}
1993-11-03 23:41:59 +00:00
}
*src_map = smp;
1993-11-03 23:41:59 +00:00
return np;
}
if (common_size == 0)
/* Not found */
return NULL;
/*
* It's a common, enter into run-time common symbol table.
*/
rtsp = enter_rts(name, (long)calloc(1, common_size),
N_UNDF + N_EXT, 0, common_size, NULL);
1993-11-03 23:41:59 +00:00
#if DEBUG
xprintf("Allocating common: %s size %d at %#x\n", name, common_size,
rtsp->rt_sp->nz_value);
1993-11-03 23:41:59 +00:00
#endif
return rtsp->rt_sp;
}
/*
* This routine is called from the jumptable to resolve
* procedure calls to shared objects.
*/
long
1993-11-03 23:41:59 +00:00
binder(jsp)
jmpslot_t *jsp;
1993-11-03 23:41:59 +00:00
{
struct so_map *smp, *src_map = NULL;
1993-11-03 23:41:59 +00:00
long addr;
char *sym;
struct nzlist *np;
int index;
/*
* Find the PLT map that contains JSP.
*/
for (smp = link_map_head; smp; smp = smp->som_next) {
if (LM_PLT(smp) < jsp &&
jsp < LM_PLT(smp) + LD_PLTSZ(smp->som_dynamic)/sizeof(*jsp))
1993-11-03 23:41:59 +00:00
break;
}
if (smp == NULL)
errx(1, "Call to binder from unknown location: %#x\n", jsp);
1993-11-03 23:41:59 +00:00
index = jsp->reloc_index & JMPSLOT_RELOC_MASK;
/* Get the local symbol this jmpslot refers to */
sym = LM_STRINGS(smp) +
LM_SYMBOL(smp,RELOC_SYMBOL(&LM_REL(smp)[index]))->nz_strx;
1993-11-03 23:41:59 +00:00
np = lookup(sym, &src_map, 1);
1993-11-03 23:41:59 +00:00
if (np == NULL)
errx(1, "Undefined symbol \"%s\" called from %s:%s at %#x",
sym, main_progname, smp->som_path, jsp);
1993-11-03 23:41:59 +00:00
/* Fixup jmpslot so future calls transfer directly to target */
addr = np->nz_value;
if (src_map)
addr += (long)src_map->som_addr;
1993-11-03 23:41:59 +00:00
md_fix_jmpslot(jsp, (long)jsp, addr);
#if DEBUG
xprintf(" BINDER: %s located at = %#x in %s\n", sym, addr,
src_map->som_path);
1993-11-03 23:41:59 +00:00
#endif
return addr;
}
static int hfd;
static long hsize;
1993-11-03 23:41:59 +00:00
static struct hints_header *hheader;
static struct hints_bucket *hbuckets;
static char *hstrtab;
#define HINTS_VALID (hheader != NULL && hheader != (struct hints_header *)-1)
static void
maphints __P((void))
1993-11-03 23:41:59 +00:00
{
caddr_t addr;
if ((hfd = open(_PATH_LD_HINTS, O_RDONLY, 0)) == -1) {
1993-11-03 23:41:59 +00:00
hheader = (struct hints_header *)-1;
return;
}
hsize = PAGSIZ;
addr = mmap(0, hsize, PROT_READ, MAP_COPY, hfd, 0);
1993-11-03 23:41:59 +00:00
if (addr == (caddr_t)-1) {
close(hfd);
1993-11-03 23:41:59 +00:00
hheader = (struct hints_header *)-1;
return;
}
hheader = (struct hints_header *)addr;
if (HH_BADMAG(*hheader)) {
munmap(addr, hsize);
close(hfd);
1993-11-03 23:41:59 +00:00
hheader = (struct hints_header *)-1;
return;
}
if (hheader->hh_version != LD_HINTS_VERSION_1) {
munmap(addr, hsize);
close(hfd);
1993-11-03 23:41:59 +00:00
hheader = (struct hints_header *)-1;
return;
}
if (hheader->hh_ehints > hsize) {
if (mmap(addr+hsize, hheader->hh_ehints - hsize,
PROT_READ, MAP_COPY|MAP_FIXED,
hfd, hsize) != (caddr_t)(addr+hsize)) {
1993-11-03 23:41:59 +00:00
munmap((caddr_t)hheader, hsize);
close(hfd);
1993-11-03 23:41:59 +00:00
hheader = (struct hints_header *)-1;
return;
}
}
hbuckets = (struct hints_bucket *)(addr + hheader->hh_hashtab);
hstrtab = (char *)(addr + hheader->hh_strtab);
}
static void
unmaphints()
{
if (HINTS_VALID) {
munmap((caddr_t)hheader, hsize);
close(hfd);
hheader = NULL;
}
}
int
hinthash(cp, vmajor)
char *cp;
int vmajor;
1993-11-03 23:41:59 +00:00
{
int k = 0;
while (*cp)
k = (((k << 1) + (k >> 14)) ^ (*cp++)) & 0x3fff;
k = (((k << 1) + (k >> 14)) ^ (vmajor*257)) & 0x3fff;
return k;
}
#undef major
#undef minor
static char *
1993-11-03 23:41:59 +00:00
findhint(name, major, minor, preferred_path)
char *name;
int major, minor;
char *preferred_path;
1993-11-03 23:41:59 +00:00
{
struct hints_bucket *bp;
bp = hbuckets + (hinthash(name, major) % hheader->hh_nbucket);
1993-11-03 23:41:59 +00:00
while (1) {
/* Sanity check */
if (bp->hi_namex >= hheader->hh_strtab_sz) {
warnx("Bad name index: %#x\n", bp->hi_namex);
1993-11-03 23:41:59 +00:00
break;
}
if (bp->hi_pathx >= hheader->hh_strtab_sz) {
warnx("Bad path index: %#x\n", bp->hi_pathx);
1993-11-03 23:41:59 +00:00
break;
}
if (strcmp(name, hstrtab + bp->hi_namex) == 0) {
/* It's `name', check version numbers */
if (bp->hi_major == major &&
(bp->hi_ndewey < 2 || bp->hi_minor >= minor)) {
1993-11-03 23:41:59 +00:00
if (preferred_path == NULL ||
strcmp(preferred_path,
hstrtab + bp->hi_pathx) == 0) {
return hstrtab + bp->hi_pathx;
}
}
}
if (bp->hi_next == -1)
break;
/* Move on to next in bucket */
bp = &hbuckets[bp->hi_next];
}
/* No hints available for name */
return NULL;
}
static char *
1993-11-03 23:41:59 +00:00
rtfindlib(name, major, minor, usehints)
char *name;
int major, minor;
int *usehints;
1993-11-03 23:41:59 +00:00
{
Changed the terminology for what used to be called the "memorizing" vector. Now it is called the "symbol caching" vector. This was made possible and unconfusing by other changes that allowed me to localize everything having to do with the caching vector in the function reloc_map(). Switched to alloca() for allocating the caching vector, and eliminated the special mmap-based allocation routines. Although this was motivated by performance reasons, it led to significant simplification of the code, and made it possible to confine the symbol caching code to the single function reloc_map(). Got rid of the unnecessary and inefficient division loop at the beginning of rtld(). Reduced the number of calls to getenv("LD_LIBRARY_PATH") to just 1, on suggestion from <davidg@root.com>. Added breaks out of the relocation loops when the relocation address is found to be 0. A relocation address of 0 is caused by an unused relocation entry. Unused relocation entries are caused by linking a shared object with the "-Bsymbolic" switch. The runtime linker itself is linked that way, and the last 40% of its relocation entries are unused. Thus, breaking out of the loop on the first such entry is a performance win when ld.so relocates itself. As a side benefit, it permits removing a test from md_relocate_simple() in ../i386/md-static-funcs.c. Unused relocation entries in other shared objects (linked with "-Bsymbolic") caused even bigger problems in previous versions of the runtime linker. The runtime linker interpreted the unused entries as if they were valid. That caused it to perform repeated relocations of the first byte of the shared object. In order to do that, it had to remap the text segment writable. Breaking out of the loop on the first unused relocation entry solves that. Submitted by: John Polstra <jdp@polstra.com>
1995-11-02 18:48:15 +00:00
char *cp, *ld_path = ld_library_path;
int realminor;
1993-11-03 23:41:59 +00:00
if (hheader == NULL)
maphints();
if (!HINTS_VALID || !(*usehints))
goto lose;
1993-11-03 23:41:59 +00:00
if (ld_path != NULL) {
/* Prefer paths from LD_LIBRARY_PATH */
while ((cp = strsep(&ld_path, ":")) != NULL) {
1993-11-03 23:41:59 +00:00
cp = findhint(name, major, minor, cp);
if (ld_path)
*(ld_path-1) = ':';
if (cp)
return cp;
1993-11-03 23:41:59 +00:00
}
/* Not found in hints, try directory search */
realminor = -1;
cp = (char *)findshlib(name, &major, &realminor, 0);
if (cp && realminor >= minor)
return cp;
1993-11-03 23:41:59 +00:00
}
/* No LD_LIBRARY_PATH or lib not found in there; check default */
cp = findhint(name, major, minor, NULL);
if (cp)
return cp;
lose:
1993-11-03 23:41:59 +00:00
/* No hints available for name */
*usehints = 0;
realminor = -1;
cp = (char *)findshlib(name, &major, &realminor, 0);
if (cp) {
if (realminor < minor && getenv("LD_SUPPRESS_WARNINGS") == NULL)
warnx("warning: lib%s.so.%d.%d: "
"minor version < %d expected, using it anyway",
name, major, realminor, minor);
return cp;
}
generror ("Can't find shared library \"%s\"",
name);
return NULL;
1993-11-03 23:41:59 +00:00
}
static struct somap_private dlmap_private = {
0,
(struct so_map *)0,
0,
#ifdef SUN_COMPAT
0,
#endif
};
static struct so_map dlmap = {
(caddr_t)0,
"internal",
(struct so_map *)0,
(struct sod *)0,
(caddr_t)0,
(u_int)0,
(struct _dynamic *)0,
(caddr_t)&dlmap_private
};
/*
* Buffer for error messages and a pointer that is set to point to the buffer
* when a error occurs. It acts as a last error flag, being set to NULL
* after an error is returned.
*/
#define DLERROR_BUF_SIZE 512
static char dlerror_buf [DLERROR_BUF_SIZE];
static char *dlerror_msg = NULL;
static void *
__dlopen(name, mode)
char *name;
int mode;
1993-11-03 23:41:59 +00:00
{
struct sod *sodp;
struct so_map *smp;
/*
* A NULL argument returns the current set of mapped objects.
*/
if (name == NULL) {
LM_PRIVATE(link_map_head)->spd_refcount++;
return link_map_head;
}
if ((sodp = (struct sod *)malloc(sizeof(struct sod))) == NULL) {
generror ("malloc failed: %s", strerror (errno));
return NULL;
}
sodp->sod_name = (long)strdup(name);
sodp->sod_library = 0;
sodp->sod_major = sodp->sod_minor = 0;
if ((smp = load_object(sodp, &dlmap, RTLD_DL, 1)) == NULL) {
#ifdef DEBUG
xprintf("%s: %s\n", name, dlerror_buf);
#endif
return NULL;
}
/*
* If this was newly loaded, call the _init() function in the
* object as per manpage.
*/
if (LM_PRIVATE(smp)->spd_refcount == 1)
call_map(smp, "__init");
return smp;
1993-11-03 23:41:59 +00:00
}
static int
__dlclose(fd)
void *fd;
1993-11-03 23:41:59 +00:00
{
struct so_map *smp = (struct so_map *)fd;
#ifdef DEBUG
xprintf("dlclose(%s): refcount = %d\n", smp->som_path,
LM_PRIVATE(smp)->spd_refcount);
#endif
if (smp == NULL) {
generror("NULL argument to dlclose");
return -1;
}
if (LM_PRIVATE(smp)->spd_refcount > 1) {
LM_PRIVATE(smp)->spd_refcount--;
return 0;
}
/*
* Call the function _fini() in the object as per manpage.
*/
call_map(smp, "__fini");
1995-05-30 05:05:38 +00:00
free((void*) smp->som_sod->sod_name);
free(smp->som_sod);
if (unload_object(smp) < 0)
return -1;
return 0;
1993-11-03 23:41:59 +00:00
}
static void *
__dlsym(fd, sym)
void *fd;
char *sym;
1993-11-03 23:41:59 +00:00
{
struct so_map *smp = (struct so_map *)fd, *src_map = NULL;
struct nzlist *np;
long addr;
/*
* Restrict search to passed map if dlopen()ed.
*/
if (smp && LM_PRIVATE(smp)->spd_flags & RTLD_DL)
src_map = smp;
np = lookup(sym, &src_map, 1);
if (np == NULL) {
generror ("Symbol \"%s\" not found", sym);
return NULL;
}
/* Fixup jmpslot so future calls transfer directly to target */
addr = np->nz_value;
if (src_map)
addr += (long)src_map->som_addr;
return (void *)addr;
}
static char *
__dlerror __P((void))
{
char *err;
err = dlerror_msg;
dlerror_msg = NULL; /* Next call will return NULL */
return err;
}
static void
__dlexit __P((void))
{
struct so_map *smp;
for (smp = link_map_head; smp; smp = smp->som_next) {
if (LM_PRIVATE(smp)->spd_flags & (RTLD_RTLD|RTLD_MAIN))
continue;
call_map(smp, ".fini");
}
}
/*
* Generate an error message that can be later be retrieved via dlerror.
*/
static void
#if __STDC__
generror(char *fmt, ...)
#else
generror(fmt, va_alist)
char *fmt;
#endif
{
va_list ap;
#if __STDC__
va_start(ap, fmt);
#else
va_start(ap);
#endif
vsnprintf (dlerror_buf, DLERROR_BUF_SIZE, fmt, ap);
dlerror_msg = dlerror_buf;
va_end(ap);
1993-11-03 23:41:59 +00:00
}
void
#if __STDC__
xprintf(char *fmt, ...)
#else
xprintf(fmt, va_alist)
char *fmt;
#endif
{
char buf[256];
va_list ap;
#if __STDC__
va_start(ap, fmt);
#else
va_start(ap);
#endif
vsprintf(buf, fmt, ap);
(void)write(1, buf, strlen(buf));
va_end(ap);
}