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LD_PRELOAD support

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This commit is contained in:
Rich Felker 2011-08-16 00:24:36 -04:00
commit 2719cc8628
1 changed files with 20 additions and 0 deletions
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20
src/ldso/dynlink.c
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@ -14,6 +14,7 @@
#include <elf.h> #include <elf.h>
#include <setjmp.h> #include <setjmp.h>
#include <pthread.h> #include <pthread.h>
#include <ctype.h>
#include <dlfcn.h> #include <dlfcn.h>
#include "reloc.h" #include "reloc.h"
@ -410,6 +411,20 @@ static void load_deps(struct dso *p)
} }
} }
static void load_preload(char *s)
{
int tmp;
char *z;
for (z=s; *z; s=z) {
for ( ; *s && isspace(*s); s++);
for (z=s; *z && !isspace(*z); z++);
tmp = *z;
*z = 0;
load_library(s);
*z = tmp;
}
}
static void make_global(struct dso *p) static void make_global(struct dso *p)
{ {
for (; p; p=p->next) p->global = 1; for (; p; p=p->next) p->global = 1;
@ -455,11 +470,14 @@ void *__dynlink(int argc, char **argv, size_t *got)
struct dso *const lib = builtin_dsos+1; struct dso *const lib = builtin_dsos+1;
struct dso *const vdso = builtin_dsos+2; struct dso *const vdso = builtin_dsos+2;
size_t vdso_base=0; size_t vdso_base=0;
char *env_preload=0;
/* Find aux vector just past environ[] */ /* Find aux vector just past environ[] */
for (i=argc+1; argv[i]; i++) for (i=argc+1; argv[i]; i++)
if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16)) if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
env_path = argv[i]+16; env_path = argv[i]+16;
else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
env_preload = argv[i]+11;
auxv = (void *)(argv+i+1); auxv = (void *)(argv+i+1);
decode_vec(auxv, aux, AUX_CNT); decode_vec(auxv, aux, AUX_CNT);
@ -475,6 +493,7 @@ void *__dynlink(int argc, char **argv, size_t *got)
if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID] if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
|| aux[AT_GID]!=aux[AT_EGID]) { || aux[AT_GID]!=aux[AT_EGID]) {
env_path = 0; env_path = 0;
env_preload = 0;
} }
/* Relocate ldso's DYNAMIC pointer and load vector */ /* Relocate ldso's DYNAMIC pointer and load vector */
@ -547,6 +566,7 @@ void *__dynlink(int argc, char **argv, size_t *got)
head = tail = app; head = tail = app;
libc = lib; libc = lib;
app->next = 0; app->next = 0;
if (env_preload) load_preload(env_preload);
load_deps(head); load_deps(head);
make_global(head); make_global(head);