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Revert "Add support for protected local symbol lookup."

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This reverts commit d97e9f546e.

Bug: 17107521
Change-Id: I2b81ce2b5a4a2d166133a2626e49d81b6aef3672
This commit is contained in:
Dmitriy Ivanov
2014-08-18 15:08:51 -07:00
parent d8e007695c
commit 9419420919
8 changed files with 31 additions and 163 deletions
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38
linker/linker.cpp
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@@ -125,11 +125,6 @@ enum RelocationKind {
kRelocMax
};
enum class SymbolLookupScope {
kAllowLocal,
kExcludeLocal,
};
#if STATS
struct linker_stats_t {
int count[kRelocMax];
@@ -433,7 +428,7 @@ int dl_iterate_phdr(int (*cb)(dl_phdr_info* info, size_t size, void* data), void
return rv;
}
static ElfW(Sym)* soinfo_elf_lookup(soinfo* si, unsigned hash, const char* name, const SymbolLookupScope& lookup_scope) {
static ElfW(Sym)* soinfo_elf_lookup(soinfo* si, unsigned hash, const char* name) {
ElfW(Sym)* symtab = si->symtab;
const char* strtab = si->strtab;
@@ -444,6 +439,7 @@ static ElfW(Sym)* soinfo_elf_lookup(soinfo* si, unsigned hash, const char* name,
ElfW(Sym)* s = symtab + n;
if (strcmp(strtab + s->st_name, name)) continue;
/* only concern ourselves with global and weak symbol definitions */
switch (ELF_ST_BIND(s->st_info)) {
case STB_GLOBAL:
case STB_WEAK:
@@ -456,13 +452,7 @@ static ElfW(Sym)* soinfo_elf_lookup(soinfo* si, unsigned hash, const char* name,
static_cast<size_t>(s->st_size));
return s;
case STB_LOCAL:
if (lookup_scope != SymbolLookupScope::kAllowLocal) {
continue;
}
TRACE_TYPE(LOOKUP, "FOUND LOCAL %s in %s (%p) %zd",
name, si->name, reinterpret_cast<void*>(s->st_value),
static_cast<size_t>(s->st_size));
return s;
continue;
default:
__libc_fatal("ERROR: Unexpected ST_BIND value: %d for '%s' in '%s'",
ELF_ST_BIND(s->st_info), name, si->name);
@@ -500,7 +490,7 @@ static ElfW(Sym)* soinfo_do_lookup(soinfo* si, const char* name, soinfo** lsi, s
*/
if (si == somain) {
s = soinfo_elf_lookup(si, elf_hash, name, SymbolLookupScope::kAllowLocal);
s = soinfo_elf_lookup(si, elf_hash, name);
if (s != NULL) {
*lsi = si;
goto done;
@@ -517,7 +507,7 @@ static ElfW(Sym)* soinfo_do_lookup(soinfo* si, const char* name, soinfo** lsi, s
if (!si->has_DT_SYMBOLIC) {
DEBUG("%s: looking up %s in executable %s",
si->name, name, somain->name);
s = soinfo_elf_lookup(somain, elf_hash, name, SymbolLookupScope::kExcludeLocal);
s = soinfo_elf_lookup(somain, elf_hash, name);
if (s != NULL) {
*lsi = somain;
goto done;
@@ -534,7 +524,7 @@ static ElfW(Sym)* soinfo_do_lookup(soinfo* si, const char* name, soinfo** lsi, s
* and some the first non-weak definition. This is system dependent.
* Here we return the first definition found for simplicity. */
s = soinfo_elf_lookup(si, elf_hash, name, SymbolLookupScope::kAllowLocal);
s = soinfo_elf_lookup(si, elf_hash, name);
if (s != NULL) {
*lsi = si;
goto done;
@@ -548,7 +538,7 @@ static ElfW(Sym)* soinfo_do_lookup(soinfo* si, const char* name, soinfo** lsi, s
if (si->has_DT_SYMBOLIC) {
DEBUG("%s: looking up %s in executable %s after local scope",
si->name, name, somain->name);
s = soinfo_elf_lookup(somain, elf_hash, name, SymbolLookupScope::kExcludeLocal);
s = soinfo_elf_lookup(somain, elf_hash, name);
if (s != NULL) {
*lsi = somain;
goto done;
@@ -559,7 +549,7 @@ static ElfW(Sym)* soinfo_do_lookup(soinfo* si, const char* name, soinfo** lsi, s
/* Next, look for it in the preloads list */
for (int i = 0; g_ld_preloads[i] != NULL; i++) {
s = soinfo_elf_lookup(g_ld_preloads[i], elf_hash, name, SymbolLookupScope::kExcludeLocal);
s = soinfo_elf_lookup(g_ld_preloads[i], elf_hash, name);
if (s != NULL) {
*lsi = g_ld_preloads[i];
goto done;
@@ -569,7 +559,7 @@ static ElfW(Sym)* soinfo_do_lookup(soinfo* si, const char* name, soinfo** lsi, s
for (int i = 0; needed[i] != NULL; i++) {
DEBUG("%s: looking up %s in %s",
si->name, name, needed[i]->name);
s = soinfo_elf_lookup(needed[i], elf_hash, name, SymbolLookupScope::kExcludeLocal);
s = soinfo_elf_lookup(needed[i], elf_hash, name);
if (s != NULL) {
*lsi = needed[i];
goto done;
@@ -605,7 +595,7 @@ class SoinfoListAllocatorRW {
// This is used by dlsym(3). It performs symbol lookup only within the
// specified soinfo object and its dependencies in breadth first order.
ElfW(Sym)* dlsym_handle_lookup(soinfo* si, soinfo** found, const char* name, soinfo* caller) {
ElfW(Sym)* dlsym_handle_lookup(soinfo* si, soinfo** found, const char* name) {
LinkedList<soinfo, SoinfoListAllocatorRW> visit_list;
LinkedList<soinfo, SoinfoListAllocatorRW> visited;
visit_list.push_back(si);
@@ -615,8 +605,7 @@ ElfW(Sym)* dlsym_handle_lookup(soinfo* si, soinfo** found, const char* name, soi
continue;
}
ElfW(Sym)* result = soinfo_elf_lookup(current_soinfo, elfhash(name), name,
caller == current_soinfo ? SymbolLookupScope::kAllowLocal : SymbolLookupScope::kExcludeLocal);
ElfW(Sym)* result = soinfo_elf_lookup(current_soinfo, elfhash(name), name);
if (result != nullptr) {
*found = current_soinfo;
@@ -641,7 +630,7 @@ ElfW(Sym)* dlsym_handle_lookup(soinfo* si, soinfo** found, const char* name, soi
beginning of the global solist. Otherwise the search starts at the
specified soinfo (for RTLD_NEXT).
*/
ElfW(Sym)* dlsym_linear_lookup(const char* name, soinfo** found, soinfo* start, soinfo* caller) {
ElfW(Sym)* dlsym_linear_lookup(const char* name, soinfo** found, soinfo* start) {
unsigned elf_hash = elfhash(name);
if (start == NULL) {
@@ -650,8 +639,7 @@ ElfW(Sym)* dlsym_linear_lookup(const char* name, soinfo** found, soinfo* start,
ElfW(Sym)* s = NULL;
for (soinfo* si = start; (s == NULL) && (si != NULL); si = si->next) {
s = soinfo_elf_lookup(si, elf_hash, name,
caller == si ? SymbolLookupScope::kAllowLocal : SymbolLookupScope::kExcludeLocal);
s = soinfo_elf_lookup(si, elf_hash, name);
if (s != NULL) {
*found = si;
break;