Add RTLD_NOLOAD support and some related changes.
* Aligned RTLD_ values with glibc for lp64
* dlopen supports RTLD_NOLOAD flag
* soinfo_unload calls find_library(.., RTLD_NOLOAD)
instead of naive find_loaded_library_by_name()
* dlopen changed to add child to caller soinfo instead
of somain.
Bug: https://code.google.com/p/android/issues/detail?id=64069
Change-Id: I1a65f2c34f3e0edc6d2c41a2e408b58195feb640
diff --git a/linker/linker.cpp b/linker/linker.cpp
index 5861267..881bcc2 100644
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -682,7 +682,7 @@
return fd;
}
-static soinfo* load_library(const char* name, const android_dlextinfo* extinfo) {
+static soinfo* load_library(const char* name, int dlflags, const android_dlextinfo* extinfo) {
// Open the file.
int fd = open_library(name);
if (fd == -1) {
@@ -710,6 +710,10 @@
}
}
+ if ((dlflags & RTLD_NOLOAD) != 0) {
+ return NULL;
+ }
+
// Read the ELF header and load the segments.
if (!elf_reader.Load(extinfo)) {
return NULL;
@@ -748,33 +752,37 @@
return NULL;
}
-static soinfo* find_library_internal(const char* name, const android_dlextinfo* extinfo) {
+static soinfo* find_library_internal(const char* name, int dlflags, const android_dlextinfo* extinfo) {
if (name == NULL) {
return somain;
}
soinfo* si = find_loaded_library_by_name(name);
- if (si != NULL) {
- if (si->flags & FLAG_LINKED) {
- return si;
- }
- DL_ERR("OOPS: recursive link to \"%s\"", si->name);
+
+ // Library might still be loaded, the accurate detection
+ // of this fact is done by load_library
+ if (si == NULL) {
+ TRACE("[ '%s' has not been found by name. Trying harder...]", name);
+ si = load_library(name, dlflags, extinfo);
+ }
+
+ if (si != NULL && (si->flags & FLAG_LINKED) == 0) {
+ DL_ERR("recursive link to \"%s\"", si->name);
return NULL;
}
- TRACE("[ '%s' has not been loaded yet. Locating...]", name);
- return load_library(name, extinfo);
+ return si;
}
-static soinfo* find_library(const char* name, const android_dlextinfo* extinfo) {
- soinfo* si = find_library_internal(name, extinfo);
+static soinfo* find_library(const char* name, int dlflags, const android_dlextinfo* extinfo) {
+ soinfo* si = find_library_internal(name, dlflags, extinfo);
if (si != NULL) {
si->ref_count++;
}
return si;
}
-static int soinfo_unload(soinfo* si) {
+static void soinfo_unload(soinfo* si) {
if (si->ref_count == 1) {
TRACE("unloading '%s'", si->name);
si->CallDestructors();
@@ -789,7 +797,14 @@
if (d->d_tag == DT_NEEDED) {
const char* library_name = si->strtab + d->d_un.d_val;
TRACE("%s needs to unload %s", si->name, library_name);
- soinfo_unload(find_loaded_library_by_name(library_name));
+ soinfo* needed = find_library(library_name, RTLD_NOLOAD, NULL);
+ if (needed != NULL) {
+ soinfo_unload(needed);
+ } else {
+ // Not found: for example if symlink was deleted between dlopen and dlclose
+ // Since we cannot really handle errors at this point - print and continue.
+ PRINT("warning: couldn't find %s needed by %s on unload.", library_name, si->name);
+ }
}
}
}
@@ -801,7 +816,6 @@
si->ref_count--;
TRACE("not unloading '%s', decrementing ref_count to %zd", si->name, si->ref_count);
}
- return 0;
}
void do_android_get_LD_LIBRARY_PATH(char* buffer, size_t buffer_size) {
@@ -814,8 +828,8 @@
}
}
-soinfo* do_dlopen(const char* name, int flags, const android_dlextinfo* extinfo) {
- if ((flags & ~(RTLD_NOW|RTLD_LAZY|RTLD_LOCAL|RTLD_GLOBAL)) != 0) {
+soinfo* do_dlopen(const char* name, int flags, soinfo* caller, const android_dlextinfo* extinfo) {
+ if ((flags & ~(RTLD_NOW|RTLD_LAZY|RTLD_LOCAL|RTLD_GLOBAL|RTLD_NOLOAD)) != 0) {
DL_ERR("invalid flags to dlopen: %x", flags);
return NULL;
}
@@ -824,20 +838,21 @@
return NULL;
}
protect_data(PROT_READ | PROT_WRITE);
- soinfo* si = find_library(name, extinfo);
+ soinfo* si = find_library(name, flags, extinfo);
if (si != NULL) {
si->CallConstructors();
- somain->add_child(si);
+ if (caller != NULL) {
+ caller->add_child(si);
+ }
}
protect_data(PROT_READ);
return si;
}
-int do_dlclose(soinfo* si) {
+void do_dlclose(soinfo* si) {
protect_data(PROT_READ | PROT_WRITE);
- int result = soinfo_unload(si);
+ soinfo_unload(si);
protect_data(PROT_READ);
- return result;
}
#if defined(USE_RELA)
@@ -1435,6 +1450,10 @@
// DT_FINI should be called after DT_FINI_ARRAY if both are present.
CallFunction("DT_FINI", fini_func);
+
+ // This is needed on second call to dlopen
+ // after library has been unloaded with RTLD_NODELETE
+ constructors_called = false;
}
void soinfo::add_child(soinfo* child) {
@@ -1811,7 +1830,7 @@
memset(g_ld_preloads, 0, sizeof(g_ld_preloads));
size_t preload_count = 0;
for (size_t i = 0; g_ld_preload_names[i] != NULL; i++) {
- soinfo* lsi = find_library(g_ld_preload_names[i], NULL);
+ soinfo* lsi = find_library(g_ld_preload_names[i], 0, NULL);
if (lsi != NULL) {
g_ld_preloads[preload_count++] = lsi;
} else {
@@ -1829,7 +1848,7 @@
if (d->d_tag == DT_NEEDED) {
const char* library_name = si->strtab + d->d_un.d_val;
DEBUG("%s needs %s", si->name, library_name);
- soinfo* lsi = find_library(library_name, NULL);
+ soinfo* lsi = find_library(library_name, 0, NULL);
if (lsi == NULL) {
strlcpy(tmp_err_buf, linker_get_error_buffer(), sizeof(tmp_err_buf));
DL_ERR("could not load library \"%s\" needed by \"%s\"; caused by %s",