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Fixed support for RTLD_NEXT in dlsym()

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The previous implementation of this flag was broken--it behaved identically
to RTLD_DEFAULT.  This adds a proper implementation, which examines the address
of the calling function, and uses it to determine which library to use to begin
the symbol search process.

Change-Id: I2ad2b46363f68932af63a3828a22f9c7987eea67
This commit is contained in:
Matt Fischer 2009-12-31 12:17:56 -06:00 committed by Garmin Android technology group
parent 350bb359fa
commit 1698d9ebfc
3 changed files with 15 additions and 5 deletions
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10
linker/dlfcn.c
View File

@ -90,9 +90,15 @@ void *dlsym(void *handle, const char *symbol)
}
if(handle == RTLD_DEFAULT) {
sym = lookup(symbol, &found);
sym = lookup(symbol, &found, NULL);
} else if(handle == RTLD_NEXT) {
sym = lookup(symbol, &found);
void *ret_addr = __builtin_return_address(0);
soinfo *si = find_containing_library(ret_addr);
sym = NULL;
if(si && si->next) {
sym = lookup(symbol, &found, si->next);
}
} else {
found = (soinfo*)handle;
sym = lookup_in_library(found, symbol);

8
linker/linker.c
View File

@ -512,13 +512,17 @@ Elf32_Sym *lookup_in_library(soinfo *si, const char *name)
/* This is used by dl_sym(). It performs a global symbol lookup.
*/
Elf32_Sym *lookup(const char *name, soinfo **found)
Elf32_Sym *lookup(const char *name, soinfo **found, soinfo *start)
{
unsigned elf_hash = 0;
Elf32_Sym *s = NULL;
soinfo *si;
for(si = solist; (s == NULL) && (si != NULL); si = si->next)
if(start == NULL) {
start = solist;
}
for(si = start; (s == NULL) && (si != NULL); si = si->next)
{
if(si->flags & FLAG_ERROR)
continue;

2
linker/linker.h
View File

@ -224,7 +224,7 @@ extern soinfo libdl_info;
soinfo *find_library(const char *name);
unsigned unload_library(soinfo *si);
Elf32_Sym *lookup_in_library(soinfo *si, const char *name);
Elf32_Sym *lookup(const char *name, soinfo **found);
Elf32_Sym *lookup(const char *name, soinfo **found, soinfo *start);
soinfo *find_containing_library(void *addr);
Elf32_Sym *find_containing_symbol(void *addr, soinfo *si);
const char *linker_get_error(void);