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gdb shared library debugging support

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provide the minimal level of dynamic linker-to-debugger glue needed to
let gdb find loaded libraries and load their symbols.
This commit is contained in:
Rich Felker 2012-04-25 00:05:42 -04:00
commit 3ec8d29c75
1 changed files with 33 additions and 6 deletions
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39
src/ldso/dynlink.c
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@ -38,15 +38,24 @@ typedef Elf64_Sym Sym;
#define R_SYM(x) ((x)>>32) #define R_SYM(x) ((x)>>32)
#endif #endif
struct dso struct debug {
{ int ver;
struct dso *next, *prev; void *head;
int refcnt; void (*bp)(void);
int state;
void *base;
};
struct dso {
unsigned char *base;
char *name;
size_t *dynv; size_t *dynv;
struct dso *next, *prev;
int refcnt;
Sym *syms; Sym *syms;
uint32_t *hashtab; uint32_t *hashtab;
char *strings; char *strings;
unsigned char *base;
unsigned char *map; unsigned char *map;
size_t map_len; size_t map_len;
dev_t dev; dev_t dev;
@ -55,7 +64,6 @@ struct dso
char relocated; char relocated;
char constructed; char constructed;
struct dso **deps; struct dso **deps;
char *name;
char buf[]; char buf[];
}; };
@ -69,6 +77,9 @@ static int ssp_used;
static int runtime; static int runtime;
static jmp_buf rtld_fail; static jmp_buf rtld_fail;
static pthread_rwlock_t lock; static pthread_rwlock_t lock;
static struct debug debug;
struct debug *_dl_debug_addr = &debug;
#define AUX_CNT 24 #define AUX_CNT 24
#define DYN_CNT 34 #define DYN_CNT 34
@ -500,6 +511,10 @@ static void do_init_fini(struct dso *p)
} }
} }
void _dl_debug_state(void)
{
}
void *__dynlink(int argc, char **argv) void *__dynlink(int argc, char **argv)
{ {
size_t *auxv, aux[AUX_CNT] = {0}; size_t *auxv, aux[AUX_CNT] = {0};
@ -608,6 +623,16 @@ void *__dynlink(int argc, char **argv)
* all memory used by the dynamic linker. */ * all memory used by the dynamic linker. */
runtime = 1; runtime = 1;
for (i=0; app->dynv[i]; i+=2)
if (app->dynv[i]==DT_DEBUG)
app->dynv[i+1] = (size_t)&debug;
debug.ver = 1;
debug.bp = _dl_debug_state;
debug.head = head;
debug.base = lib->base;
debug.state = 0;
_dl_debug_state();
do_init_fini(tail); do_init_fini(tail);
if (!rtld_used) { if (!rtld_used) {
@ -678,6 +703,8 @@ void *dlopen(const char *file, int mode)
p->global = 1; p->global = 1;
} }
_dl_debug_state();
do_init_fini(tail); do_init_fini(tail);
end: end:
pthread_rwlock_unlock(&lock); pthread_rwlock_unlock(&lock);