gdb shared library debugging support

provide the minimal level of dynamic linker-to-debugger glue needed to
let gdb find loaded libraries and load their symbols.

diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c
index d04bef62300c549a1f3563955b052e9f8922228e..3f3316aaf4ccde3c4ff7e8880d562484f99efc2a 100644 (file)
--- a/src/ldso/dynlink.c
+++ b/src/ldso/dynlink.c
@@ -38,15 +38,24 @@ typedef Elf64_Sym Sym;
 #define R_SYM(x) ((x)>>32)
 #endif
 
-struct dso
-{
+struct debug {
+       int ver;
+       void *head;
+       void (*bp)(void);
+       int state;
+       void *base;
+};
+
+struct dso {
+       unsigned char *base;
+       char *name;
+       size_t *dynv;
        struct dso *next, *prev;
+
        int refcnt;
-       size_t *dynv;
        Sym *syms;
        uint32_t *hashtab;
        char *strings;
-       unsigned char *base;
        unsigned char *map;
        size_t map_len;
        dev_t dev;
@@ -55,7 +64,6 @@ struct dso
        char relocated;
        char constructed;
        struct dso **deps;
-       char *name;
        char buf[];
 };
 
@@ -69,6 +77,9 @@ static int ssp_used;
 static int runtime;
 static jmp_buf rtld_fail;
 static pthread_rwlock_t lock;
+static struct debug debug;
+
+struct debug *_dl_debug_addr = &debug;
 
 #define AUX_CNT 24
 #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)
 {
        size_t *auxv, aux[AUX_CNT] = {0};
@@ -608,6 +623,16 @@ void *__dynlink(int argc, char **argv)
         * all memory used by the dynamic linker. */
        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);
 
        if (!rtld_used) {
@@ -678,6 +703,8 @@ void *dlopen(const char *file, int mode)
                p->global = 1;
        }
 
+       _dl_debug_state();
+
        do_init_fini(tail);
 end:
        pthread_rwlock_unlock(&lock);