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>

1 files changed, 35 insertions, 4 deletions

diff --git a/ldso/libdl/libdl.c b/ldso/libdl/libdl.c
index edf336684..6dc60587b 100644
--- 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;
 	}