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Implement rtld part of the support for -z nodlopen (see ld(1)).

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Reviewed by:	kan
MFC after:	3 weeks
This commit is contained in:
kib 2009-11-26 13:57:20 +00:00
parent 0dba9623fa
commit 8f8a9dcd17
3 changed files with 32 additions and 14 deletions
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40
libexec/rtld-elf/rtld.c
View File

@ -87,7 +87,7 @@ static void die(void) __dead2;
static void digest_dynamic(Obj_Entry *, int); static void digest_dynamic(Obj_Entry *, int);
static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
static Obj_Entry *dlcheck(void *); static Obj_Entry *dlcheck(void *);
static Obj_Entry *do_load_object(int, const char *, char *, struct stat *); static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
static bool donelist_check(DoneList *, const Obj_Entry *); static bool donelist_check(DoneList *, const Obj_Entry *);
static void errmsg_restore(char *); static void errmsg_restore(char *);
@ -103,7 +103,7 @@ static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
static bool is_exported(const Elf_Sym *); static bool is_exported(const Elf_Sym *);
static void linkmap_add(Obj_Entry *); static void linkmap_add(Obj_Entry *);
static void linkmap_delete(Obj_Entry *); static void linkmap_delete(Obj_Entry *);
static int load_needed_objects(Obj_Entry *); static int load_needed_objects(Obj_Entry *, int);
static int load_preload_objects(void); static int load_preload_objects(void);
static Obj_Entry *load_object(const char *, const Obj_Entry *, int); static Obj_Entry *load_object(const char *, const Obj_Entry *, int);
static Obj_Entry *obj_from_addr(const void *); static Obj_Entry *obj_from_addr(const void *);
@ -485,7 +485,7 @@ _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
preload_tail = obj_tail; preload_tail = obj_tail;
dbg("loading needed objects"); dbg("loading needed objects");
if (load_needed_objects(obj_main) == -1) if (load_needed_objects(obj_main, 0) == -1)
die(); die();
/* Make a list of all objects loaded at startup. */ /* Make a list of all objects loaded at startup. */
@ -932,6 +932,8 @@ digest_dynamic(Obj_Entry *obj, int early)
#endif #endif
case DT_FLAGS_1: case DT_FLAGS_1:
if (dynp->d_un.d_val & DF_1_NOOPEN)
obj->z_noopen = true;
if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
obj->z_origin = true; obj->z_origin = true;
if (dynp->d_un.d_val & DF_1_GLOBAL) if (dynp->d_un.d_val & DF_1_GLOBAL)
@ -1425,7 +1427,7 @@ is_exported(const Elf_Sym *def)
* returns -1 on failure. * returns -1 on failure.
*/ */
static int static int
load_needed_objects(Obj_Entry *first) load_needed_objects(Obj_Entry *first, int flags)
{ {
Obj_Entry *obj, *obj1; Obj_Entry *obj, *obj1;
@ -1434,7 +1436,7 @@ load_needed_objects(Obj_Entry *first)
for (needed = obj->needed; needed != NULL; needed = needed->next) { for (needed = obj->needed; needed != NULL; needed = needed->next) {
obj1 = needed->obj = load_object(obj->strtab + needed->name, obj, obj1 = needed->obj = load_object(obj->strtab + needed->name, obj,
false); flags & ~RTLD_LO_NOLOAD);
if (obj1 == NULL && !ld_tracing) if (obj1 == NULL && !ld_tracing)
return -1; return -1;
if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) { if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) {
@ -1465,7 +1467,7 @@ load_preload_objects(void)
savech = p[len]; savech = p[len];
p[len] = '\0'; p[len] = '\0';
if (load_object(p, NULL, false) == NULL) if (load_object(p, NULL, 0) == NULL)
return -1; /* XXX - cleanup */ return -1; /* XXX - cleanup */
p[len] = savech; p[len] = savech;
p += len; p += len;
@ -1482,7 +1484,7 @@ load_preload_objects(void)
* on failure. * on failure.
*/ */
static Obj_Entry * static Obj_Entry *
load_object(const char *name, const Obj_Entry *refobj, int noload) load_object(const char *name, const Obj_Entry *refobj, int flags)
{ {
Obj_Entry *obj; Obj_Entry *obj;
int fd = -1; int fd = -1;
@ -1528,11 +1530,11 @@ load_object(const char *name, const Obj_Entry *refobj, int noload)
close(fd); close(fd);
return obj; return obj;
} }
if (noload) if (flags & RTLD_LO_NOLOAD)
return (NULL); return (NULL);
/* First use of this object, so we must map it in */ /* First use of this object, so we must map it in */
obj = do_load_object(fd, name, path, &sb); obj = do_load_object(fd, name, path, &sb, flags);
if (obj == NULL) if (obj == NULL)
free(path); free(path);
close(fd); close(fd);
@ -1541,7 +1543,8 @@ load_object(const char *name, const Obj_Entry *refobj, int noload)
} }
static Obj_Entry * static Obj_Entry *
do_load_object(int fd, const char *name, char *path, struct stat *sbp) do_load_object(int fd, const char *name, char *path, struct stat *sbp,
int flags)
{ {
Obj_Entry *obj; Obj_Entry *obj;
struct statfs fs; struct statfs fs;
@ -1568,6 +1571,13 @@ do_load_object(int fd, const char *name, char *path, struct stat *sbp)
object_add_name(obj, name); object_add_name(obj, name);
obj->path = path; obj->path = path;
digest_dynamic(obj, 0); digest_dynamic(obj, 0);
if (obj->z_noopen && (flags & RTLD_LO_DLOPEN)) {
dbg("refusing to load non-loadable \"%s\"", obj->path);
_rtld_error("Cannot dlopen non-loadable %s\n", obj->path);
munmap(obj->mapbase, obj->mapsize);
obj_free(obj);
return (NULL);
}
*obj_tail = obj; *obj_tail = obj;
obj_tail = &obj->next; obj_tail = &obj->next;
@ -1986,14 +1996,16 @@ dlopen(const char *name, int mode)
Obj_Entry **old_obj_tail; Obj_Entry **old_obj_tail;
Obj_Entry *obj; Obj_Entry *obj;
Objlist initlist; Objlist initlist;
int result, lockstate, nodelete, noload; int result, lockstate, nodelete, lo_flags;
LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
if (ld_tracing != NULL) if (ld_tracing != NULL)
environ = (char **)*get_program_var_addr("environ"); environ = (char **)*get_program_var_addr("environ");
nodelete = mode & RTLD_NODELETE; nodelete = mode & RTLD_NODELETE;
noload = mode & RTLD_NOLOAD; lo_flags = RTLD_LO_DLOPEN;
if (mode & RTLD_NOLOAD)
lo_flags |= RTLD_LO_NOLOAD;
objlist_init(&initlist); objlist_init(&initlist);
@ -2006,7 +2018,7 @@ dlopen(const char *name, int mode)
obj = obj_main; obj = obj_main;
obj->refcount++; obj->refcount++;
} else { } else {
obj = load_object(name, obj_main, noload); obj = load_object(name, obj_main, lo_flags);
} }
if (obj) { if (obj) {
@ -2016,7 +2028,7 @@ dlopen(const char *name, int mode)
mode &= RTLD_MODEMASK; mode &= RTLD_MODEMASK;
if (*old_obj_tail != NULL) { /* We loaded something new. */ if (*old_obj_tail != NULL) { /* We loaded something new. */
assert(*old_obj_tail == obj); assert(*old_obj_tail == obj);
result = load_needed_objects(obj); result = load_needed_objects(obj, RTLD_LO_DLOPEN);
init_dag(obj); init_dag(obj);
if (result != -1) if (result != -1)
result = rtld_verify_versions(&obj->dagmembers); result = rtld_verify_versions(&obj->dagmembers);

5
libexec/rtld-elf/rtld.h
View File

@ -218,6 +218,7 @@ typedef struct Struct_Obj_Entry {
bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */ bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */
bool z_origin : 1; /* Process rpath and soname tokens */ bool z_origin : 1; /* Process rpath and soname tokens */
bool z_nodelete : 1; /* Do not unload the object and dependencies */ bool z_nodelete : 1; /* Do not unload the object and dependencies */
bool z_noopen : 1; /* Do not load on dlopen */
bool ref_nodel : 1; /* Refcount increased to prevent dlclose */ bool ref_nodel : 1; /* Refcount increased to prevent dlclose */
bool init_scanned: 1; /* Object is already on init list. */ bool init_scanned: 1; /* Object is already on init list. */
bool on_fini_list: 1; /* Object is already on fini list. */ bool on_fini_list: 1; /* Object is already on fini list. */
@ -240,6 +241,10 @@ typedef struct Struct_Obj_Entry {
#define SYMLOOK_DLSYM 0x02 /* Return newes versioned symbol. Used by #define SYMLOOK_DLSYM 0x02 /* Return newes versioned symbol. Used by
dlsym. */ dlsym. */
/* Flags for load_object(). */
#define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD */
#define RTLD_LO_DLOPEN 0x02 /* load_object() called from dlopen(). */
/* /*
* Symbol cache entry used during relocation to avoid multiple lookups * Symbol cache entry used during relocation to avoid multiple lookups
* of the same symbol. * of the same symbol.

1
sys/sys/elf_common.h
View File

@ -471,6 +471,7 @@ typedef struct {
#define DF_1_BIND_NOW 0x00000001 /* Same as DF_BIND_NOW */ #define DF_1_BIND_NOW 0x00000001 /* Same as DF_BIND_NOW */
#define DF_1_GLOBAL 0x00000002 /* Set the RTLD_GLOBAL for object */ #define DF_1_GLOBAL 0x00000002 /* Set the RTLD_GLOBAL for object */
#define DF_1_NODELETE 0x00000008 /* Set the RTLD_NODELETE for object */ #define DF_1_NODELETE 0x00000008 /* Set the RTLD_NODELETE for object */
#define DF_1_NOOPEN 0x00000040 /* Do not allow loading on dlopen() */
#define DF_1_ORIGIN 0x00000080 /* Process $ORIGIN */ #define DF_1_ORIGIN 0x00000080 /* Process $ORIGIN */
/* Values for n_type. Used in core files. */ /* Values for n_type. Used in core files. */