This patch solves a problem in dladdr caused by the wrong value

of elf_resolve's loadaddr field for the main application.

Signed-off-by: Filippo Arcidiacono <filippo.arcidiacono@st.com>
Signed-off-by: Carmelo Amoroso <carmelo.amoroso@st.com>

diff --git a/ldso/include/dl-defs.h b/ldso/include/dl-defs.h
index 21b9c28..791d068 100644 (file)
--- a/ldso/include/dl-defs.h
+++ b/ldso/include/dl-defs.h
@@ -168,8 +168,8 @@ typedef struct {
  */
 #ifndef DL_ADDR_IN_LOADADDR
 # define DL_ADDR_IN_LOADADDR(ADDR, TPNT, TFROM) \
-       ((void*)(TPNT)->loadaddr < (void*)(ADDR) \
-        && (!(TFROM) || (TFROM)->loadaddr < (TPNT)->loadaddr))
+       ((void*)(TPNT)->mapaddr < (void*)(ADDR) \
+        && (!(TFROM) || (TFROM)->mapaddr < (TPNT)->mapaddr))
 #endif
 
 /* This is called from dladdr() to give targets that use function descriptors

diff --git a/ldso/include/dl-hash.h b/ldso/include/dl-hash.h
index 5bb1f47..193ae2d 100644 (file)
--- a/ldso/include/dl-hash.h
+++ b/ldso/include/dl-hash.h
@@ -34,6 +34,7 @@ struct elf_resolve {
   struct elf_resolve * next;
   struct elf_resolve * prev;
   /* Nothing after this address is used by gdb. */
+  DL_LOADADDR_TYPE mapaddr;    /* Address at which ELF segments (either main app and DSO) are mapped into */
   enum {elf_lib, elf_executable,program_interpreter, loaded_file} libtype;
   struct dyn_elf * symbol_scope;
   unsigned short usage_count;

diff --git a/ldso/ldso/dl-hash.c b/ldso/ldso/dl-hash.c
index 8d2ae3e..5599962 100644 (file)
--- a/ldso/ldso/dl-hash.c
+++ b/ldso/ldso/dl-hash.c
@@ -152,7 +152,7 @@ struct elf_resolve *_dl_add_elf_hash_table(const char *libname,
                hash_addr += tpnt->nbucket;
                tpnt->chains = hash_addr;
        }
-       tpnt->loadaddr = loadaddr;
+       tpnt->loadaddr = tpnt->mapaddr = loadaddr;
        for (i = 0; i < DYNAMIC_SIZE; i++)
                tpnt->dynamic_info[i] = dynamic_info[i];
        return tpnt;

diff --git a/ldso/ldso/ldso.c b/ldso/ldso/ldso.c
index d6aa0b1..15e03f5 100644 (file)
--- a/ldso/ldso/ldso.c
+++ b/ldso/ldso/ldso.c
@@ -135,6 +135,7 @@ void _dl_get_ready_to_run(struct elf_resolve *tpnt, DL_LOADADDR_TYPE load_addr,
                          char **argv
                          DL_GET_READY_TO_RUN_EXTRA_PARMS)
 {
+       DL_LOADADDR_TYPE app_loadaddr = NULL;
        ElfW(Phdr) *ppnt;
        ElfW(Dyn) *dpnt;
        char *lpntstr;
@@ -276,6 +277,9 @@ void _dl_get_ready_to_run(struct elf_resolve *tpnt, DL_LOADADDR_TYPE load_addr,
                        relro_addr = ppnt->p_vaddr;
                        relro_size = ppnt->p_memsz;
                }
+               if (!app_loadaddr && (ppnt->p_type == PT_LOAD)) {
+                       app_loadaddr = ppnt->p_vaddr;
+               }
                if (ppnt->p_type == PT_DYNAMIC) {
                        dpnt = (ElfW(Dyn) *) DL_RELOC_ADDR(app_tpnt->loadaddr, ppnt->p_vaddr);
                        _dl_parse_dynamic_info(dpnt, app_tpnt->dynamic_info, debug_addr, app_tpnt->loadaddr);
@@ -322,6 +326,7 @@ void _dl_get_ready_to_run(struct elf_resolve *tpnt, DL_LOADADDR_TYPE load_addr,
                        _dl_symbol_tables = rpnt = (struct dyn_elf *) _dl_malloc(sizeof(struct dyn_elf));
                        _dl_memset(rpnt, 0, sizeof(struct dyn_elf));
                        rpnt->dyn = _dl_loaded_modules;
+                       app_tpnt->mapaddr = app_loadaddr;
                        app_tpnt->rtld_flags = unlazy | RTLD_GLOBAL;
                        app_tpnt->usage_count++;
                        app_tpnt->symbol_scope = _dl_symbol_tables;

diff --git a/ldso/libdl/libdl.c b/ldso/libdl/libdl.c
index edf3366..6dc6058 100644 (file)
--- a/ldso/libdl/libdl.c
+++ b/ldso/libdl/libdl.c
@@ -739,13 +739,40 @@ int dladdr(const void *__address, Dl_info * __info)
                char *strtab;
                ElfW(Sym) *symtab;
                unsigned int hn, si, sn, sf;
-               ElfW(Addr) sa;
+               ElfW(Addr) sa = 0;
+
+               /* Set the info for the object the address lies in */
+               __info->dli_fname = pelf->libname;
+               __info->dli_fbase = (void *) DL_LOADADDR_BASE(pelf->mapaddr);
 
-               sa = 0;
                symtab = (ElfW(Sym) *) (pelf->dynamic_info[DT_SYMTAB]);
                strtab = (char *) (pelf->dynamic_info[DT_STRTAB]);
 
                sf = sn = 0;
+
+#ifdef __LDSO_GNU_HASH_SUPPORT__
+               if (pelf->l_gnu_bitmask) {
+                       for (hn = 0; hn < pelf->nbucket; hn++) {
+                               si = pelf->l_gnu_buckets[hn];
+                               if (!si)
+                                       continue;
+
+                               const Elf32_Word *hasharr = &pelf->l_gnu_chain_zero[si];
+                               do {
+                                       ElfW(Addr) symbol_addr;
+
+                                       symbol_addr = (ElfW(Addr)) pelf->loadaddr + symtab[si].st_value;
+                                       if (symbol_addr <= (ElfW(Addr))__address && (!sf || sa < symbol_addr)) {
+                                               sa = symbol_addr;
+                                               sn = si;
+                                               sf = 1;
+                                       }
+                                       _dl_if_debug_print("Symbol \"%s\" at %p\n", strtab + symtab[si].st_name, symbol_addr);
+                                       ++si;
+                               } while ((*hasharr++ & 1u) == 0);
+                       }
+               } else
+#endif
                for (hn = 0; hn < pelf->nbucket; hn++) {
                        for (si = pelf->elf_buckets[hn]; si; si = pelf->chains[si]) {
                                ElfW(Addr) symbol_addr;
@@ -763,10 +790,14 @@ int dladdr(const void *__address, Dl_info * __info)
                }
 
                if (sf) {
-                       __info->dli_fname = pelf->libname;
-                       __info->dli_fbase = (void *) DL_LOADADDR_BASE(pelf->loadaddr);
+                       /* A nearest symbol has been found; fill the entries */
                        __info->dli_sname = strtab + symtab[sn].st_name;
                        __info->dli_saddr = (void *)sa;
+               } else {
+                       /* No symbol found, fill entries with NULL value,
+                       only the containing object will be returned. */
+                       __info->dli_sname = NULL;
+                       __info->dli_saddr = NULL;
                }
                return 1;
        }