Merge changes Idd0fb06a,Ia17dd540,I96c6592a,I0eacb3f0,I8e2895ec, ... into nyc-dev
* changes:
Do not add linker the _r_debug.r_map on link_image
Improvements to dynamic linker messages
Move gdb support functions to a separate file
Use insert_link_map_into_debug_map for executable
Update a comment for init_linker_info_for_gdb
Initialize linker link_map for gdb directly
diff --git a/linker/Android.mk b/linker/Android.mk
index 1620888..4a4ca5c 100644
--- a/linker/Android.mk
+++ b/linker/Android.mk
@@ -11,6 +11,7 @@
linker_allocator.cpp \
linker_block_allocator.cpp \
linker_dlwarning.cpp \
+ linker_gdb_support.cpp \
linker_libc_support.c \
linker_mapped_file_fragment.cpp \
linker_memory.cpp \
diff --git a/linker/debugger.cpp b/linker/debugger.cpp
index 670d1ea..d4c7928 100644
--- a/linker/debugger.cpp
+++ b/linker/debugger.cpp
@@ -27,6 +27,7 @@
*/
#include "linker.h"
+#include "linker_gdb_support.h"
#include <errno.h>
#include <inttypes.h>
diff --git a/linker/linker.cpp b/linker/linker.cpp
index 3c7637f..faf5759 100644
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -51,6 +51,7 @@
#include "linker.h"
#include "linker_block_allocator.h"
+#include "linker_gdb_support.h"
#include "linker_debug.h"
#include "linker_dlwarning.h"
#include "linker_sleb128.h"
@@ -272,95 +273,27 @@
return sizeof(__linker_dl_err_buf);
}
-// This function is an empty stub where GDB locates a breakpoint to get notified
-// about linker activity.
-extern "C"
-void __attribute__((noinline)) __attribute__((visibility("default"))) rtld_db_dlactivity();
+static void notify_gdb_of_load(soinfo* info) {
+ if (info->is_linker() || info->is_main_executable()) {
+ // gdb already knows about the linker and the main executable.
+ return;
+ }
-static pthread_mutex_t g__r_debug_mutex = PTHREAD_MUTEX_INITIALIZER;
-static r_debug _r_debug =
- {1, nullptr, reinterpret_cast<uintptr_t>(&rtld_db_dlactivity), r_debug::RT_CONSISTENT, 0};
-
-static link_map* r_debug_tail = 0;
-
-static void insert_soinfo_into_debug_map(soinfo* info) {
- // Copy the necessary fields into the debug structure.
link_map* map = &(info->link_map_head);
+
map->l_addr = info->load_bias;
// link_map l_name field is not const.
map->l_name = const_cast<char*>(info->get_realpath());
map->l_ld = info->dynamic;
- // Stick the new library at the end of the list.
- // gdb tends to care more about libc than it does
- // about leaf libraries, and ordering it this way
- // reduces the back-and-forth over the wire.
- if (r_debug_tail) {
- r_debug_tail->l_next = map;
- map->l_prev = r_debug_tail;
- map->l_next = 0;
- } else {
- _r_debug.r_map = map;
- map->l_prev = 0;
- map->l_next = 0;
- }
- r_debug_tail = map;
-}
+ CHECK(map->l_name != nullptr);
+ CHECK(map->l_name[0] != '\0');
-static void remove_soinfo_from_debug_map(soinfo* info) {
- link_map* map = &(info->link_map_head);
-
- if (r_debug_tail == map) {
- r_debug_tail = map->l_prev;
- }
-
- if (map->l_prev) {
- map->l_prev->l_next = map->l_next;
- }
- if (map->l_next) {
- map->l_next->l_prev = map->l_prev;
- }
-}
-
-static void notify_gdb_of_load(soinfo* info) {
- if (info->is_main_executable()) {
- // GDB already knows about the main executable
- return;
- }
-
- ScopedPthreadMutexLocker locker(&g__r_debug_mutex);
-
- _r_debug.r_state = r_debug::RT_ADD;
- rtld_db_dlactivity();
-
- insert_soinfo_into_debug_map(info);
-
- _r_debug.r_state = r_debug::RT_CONSISTENT;
- rtld_db_dlactivity();
+ notify_gdb_of_load(map);
}
static void notify_gdb_of_unload(soinfo* info) {
- if (info->is_main_executable()) {
- // GDB already knows about the main executable
- return;
- }
-
- ScopedPthreadMutexLocker locker(&g__r_debug_mutex);
-
- _r_debug.r_state = r_debug::RT_DELETE;
- rtld_db_dlactivity();
-
- remove_soinfo_from_debug_map(info);
-
- _r_debug.r_state = r_debug::RT_CONSISTENT;
- rtld_db_dlactivity();
-}
-
-void notify_gdb_of_libraries() {
- _r_debug.r_state = r_debug::RT_ADD;
- rtld_db_dlactivity();
- _r_debug.r_state = r_debug::RT_CONSISTENT;
- rtld_db_dlactivity();
+ notify_gdb_of_unload(&(info->link_map_head));
}
bool android_namespace_t::is_accessible(const std::string& file) {
@@ -3349,6 +3282,10 @@
return (flags_ & FLAG_EXE) != 0;
}
+bool soinfo::is_linker() const {
+ return (flags_ & FLAG_LINKER) != 0;
+}
+
void soinfo::set_linked() {
flags_ |= FLAG_LINKED;
}
@@ -4005,33 +3942,22 @@
#endif
}
-/*
- * This is linker soinfo for GDB. See details below.
- */
-#if defined(__LP64__)
-#define LINKER_PATH "/system/bin/linker64"
-#else
-#define LINKER_PATH "/system/bin/linker"
-#endif
-
-// This is done to avoid calling c-tor prematurely
-// because soinfo c-tor needs memory allocator
-// which might be initialized after global variables.
-static uint8_t linker_soinfo_for_gdb_buf[sizeof(soinfo)] __attribute__((aligned(8)));
-static soinfo* linker_soinfo_for_gdb = nullptr;
-
/* gdb expects the linker to be in the debug shared object list.
* Without this, gdb has trouble locating the linker's ".text"
* and ".plt" sections. Gdb could also potentially use this to
* relocate the offset of our exported 'rtld_db_dlactivity' symbol.
- * Don't use soinfo_alloc(), because the linker shouldn't
- * be on the soinfo list.
+ * Note that the linker shouldn't be on the soinfo list.
*/
static void init_linker_info_for_gdb(ElfW(Addr) linker_base) {
- linker_soinfo_for_gdb = new (linker_soinfo_for_gdb_buf) soinfo(nullptr, LINKER_PATH,
- nullptr, 0, 0);
+ static link_map linker_link_map_for_gdb;
+#if defined(__LP64__)
+ static char kLinkerPath[] = "/system/bin/linker64";
+#else
+ static char kLinkerPath[] = "/system/bin/linker";
+#endif
- linker_soinfo_for_gdb->load_bias = linker_base;
+ linker_link_map_for_gdb.l_addr = linker_base;
+ linker_link_map_for_gdb.l_name = kLinkerPath;
/*
* Set the dynamic field in the link map otherwise gdb will complain with
@@ -4042,8 +3968,9 @@
ElfW(Ehdr)* elf_hdr = reinterpret_cast<ElfW(Ehdr)*>(linker_base);
ElfW(Phdr)* phdr = reinterpret_cast<ElfW(Phdr)*>(linker_base + elf_hdr->e_phoff);
phdr_table_get_dynamic_section(phdr, elf_hdr->e_phnum, linker_base,
- &linker_soinfo_for_gdb->dynamic, nullptr);
- insert_soinfo_into_debug_map(linker_soinfo_for_gdb);
+ &linker_link_map_for_gdb.l_ld, nullptr);
+
+ insert_link_map_into_debug_map(&linker_link_map_for_gdb);
}
static void init_default_namespace() {
@@ -4117,21 +4044,19 @@
soinfo* si = soinfo_alloc(&g_default_namespace, args.argv[0], nullptr, 0, RTLD_GLOBAL);
if (si == nullptr) {
- exit(EXIT_FAILURE);
+ __libc_fatal("Couldn't allocate soinfo: out of memory?");
}
/* bootstrap the link map, the main exe always needs to be first */
si->set_main_executable();
link_map* map = &(si->link_map_head);
+ // Register the main executable and the linker upfront to have
+ // gdb aware of them before loading the rest of the dependency
+ // tree.
map->l_addr = 0;
map->l_name = args.argv[0];
- map->l_prev = nullptr;
- map->l_next = nullptr;
-
- _r_debug.r_map = map;
- r_debug_tail = map;
-
+ insert_link_map_into_debug_map(map);
init_linker_info_for_gdb(linker_base);
// Extract information passed from the kernel.
@@ -4157,8 +4082,8 @@
ElfW(Ehdr)* elf_hdr = reinterpret_cast<ElfW(Ehdr)*>(si->base);
if (elf_hdr->e_type != ET_DYN) {
- __libc_format_fd(2, "error: only position independent executables (PIE) are supported.\n");
- exit(EXIT_FAILURE);
+ __libc_fatal("\"%s\": error: only position independent executables (PIE) are supported.",
+ args.argv[0]);
}
// Use LD_LIBRARY_PATH and LD_PRELOAD (but only if we aren't setuid/setgid).
@@ -4170,7 +4095,7 @@
init_default_namespace();
if (!si->prelink_image()) {
- __libc_fatal("CANNOT LINK EXECUTABLE: %s", linker_get_error_buffer());
+ __libc_fatal("CANNOT LINK EXECUTABLE \"%s\": %s", args.argv[0], linker_get_error_buffer());
}
// add somain to global group
@@ -4201,10 +4126,10 @@
!find_libraries(&g_default_namespace, si, needed_library_names, needed_libraries_count,
nullptr, &g_ld_preloads, ld_preloads_count, RTLD_GLOBAL, nullptr,
/* add_as_children */ true)) {
- __libc_fatal("CANNOT LINK EXECUTABLE: %s", linker_get_error_buffer());
+ __libc_fatal("CANNOT LINK EXECUTABLE \"%s\": %s", args.argv[0], linker_get_error_buffer());
} else if (needed_libraries_count == 0) {
if (!si->link_image(g_empty_list, soinfo::soinfo_list_t::make_list(si), nullptr)) {
- __libc_fatal("CANNOT LINK EXECUTABLE: %s", linker_get_error_buffer());
+ __libc_fatal("CANNOT LINK EXECUTABLE \"%s\": %s", args.argv[0], linker_get_error_buffer());
}
si->increment_ref_count();
}
@@ -4326,7 +4251,10 @@
// This happens when user tries to run 'adb shell /system/bin/linker'
// see also https://code.google.com/p/android/issues/detail?id=63174
if (reinterpret_cast<ElfW(Addr)>(&_start) == entry_point) {
- __libc_fatal("This is %s, the helper program for shared library executables.", args.argv[0]);
+ __libc_format_fd(STDOUT_FILENO,
+ "This is %s, the helper program for shared library executables.\n",
+ args.argv[0]);
+ exit(0);
}
linker_so.base = linker_addr;
@@ -4344,7 +4272,7 @@
// are not yet initialized, and therefore we cannot use linked_list.push_*
// functions at this point.
if (!(linker_so.prelink_image() && linker_so.link_image(g_empty_list, g_empty_list, nullptr))) {
- __libc_fatal("CANNOT LINK EXECUTABLE: %s", linker_get_error_buffer());
+ __libc_fatal("CANNOT LINK EXECUTABLE \"%s\": %s", args.argv[0], linker_get_error_buffer());
}
__libc_init_main_thread(args);
diff --git a/linker/linker.h b/linker/linker.h
index 389c5b3..f5bab84 100644
--- a/linker/linker.h
+++ b/linker/linker.h
@@ -310,6 +310,7 @@
}
bool is_linked() const;
+ bool is_linker() const;
bool is_main_executable() const;
void set_linked();
@@ -440,7 +441,6 @@
void debuggerd_init();
extern "C" abort_msg_t* g_abort_message;
-extern "C" void notify_gdb_of_libraries();
char* linker_get_error_buffer();
size_t linker_get_error_buffer_size();
diff --git a/linker/linker_gdb_support.cpp b/linker/linker_gdb_support.cpp
new file mode 100644
index 0000000..de74087
--- /dev/null
+++ b/linker/linker_gdb_support.cpp
@@ -0,0 +1,94 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "linker_gdb_support.h"
+
+#include <pthread.h>
+
+#include "private/ScopedPthreadMutexLocker.h"
+
+// This function is an empty stub where GDB locates a breakpoint to get notified
+// about linker activity.
+extern "C"
+void __attribute__((noinline)) __attribute__((visibility("default"))) rtld_db_dlactivity();
+
+r_debug _r_debug =
+ {1, nullptr, reinterpret_cast<uintptr_t>(&rtld_db_dlactivity), r_debug::RT_CONSISTENT, 0};
+
+static pthread_mutex_t g__r_debug_mutex = PTHREAD_MUTEX_INITIALIZER;
+static link_map* r_debug_tail = nullptr;
+
+void insert_link_map_into_debug_map(link_map* map) {
+ // Stick the new library at the end of the list.
+ // gdb tends to care more about libc than it does
+ // about leaf libraries, and ordering it this way
+ // reduces the back-and-forth over the wire.
+ if (r_debug_tail != nullptr) {
+ r_debug_tail->l_next = map;
+ map->l_prev = r_debug_tail;
+ map->l_next = nullptr;
+ } else {
+ _r_debug.r_map = map;
+ map->l_prev = nullptr;
+ map->l_next = nullptr;
+ }
+ r_debug_tail = map;
+}
+
+void remove_link_map_from_debug_map(link_map* map) {
+ if (r_debug_tail == map) {
+ r_debug_tail = map->l_prev;
+ }
+
+ if (map->l_prev) {
+ map->l_prev->l_next = map->l_next;
+ }
+ if (map->l_next) {
+ map->l_next->l_prev = map->l_prev;
+ }
+}
+
+void notify_gdb_of_load(link_map* map) {
+ ScopedPthreadMutexLocker locker(&g__r_debug_mutex);
+
+ _r_debug.r_state = r_debug::RT_ADD;
+ rtld_db_dlactivity();
+
+ insert_link_map_into_debug_map(map);
+
+ _r_debug.r_state = r_debug::RT_CONSISTENT;
+ rtld_db_dlactivity();
+}
+
+void notify_gdb_of_unload(link_map* map) {
+ ScopedPthreadMutexLocker locker(&g__r_debug_mutex);
+
+ _r_debug.r_state = r_debug::RT_DELETE;
+ rtld_db_dlactivity();
+
+ remove_link_map_from_debug_map(map);
+
+ _r_debug.r_state = r_debug::RT_CONSISTENT;
+ rtld_db_dlactivity();
+}
+
+void notify_gdb_of_libraries() {
+ _r_debug.r_state = r_debug::RT_ADD;
+ rtld_db_dlactivity();
+ _r_debug.r_state = r_debug::RT_CONSISTENT;
+ rtld_db_dlactivity();
+}
+
diff --git a/linker/linker_gdb_support.h b/linker/linker_gdb_support.h
new file mode 100644
index 0000000..2a590ba
--- /dev/null
+++ b/linker/linker_gdb_support.h
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef __LINKER_GDB_SUPPORT_H
+#define __LINKER_GDB_SUPPORT_H
+
+#include <link.h>
+#include <sys/cdefs.h>
+
+__BEGIN_DECLS
+
+void insert_link_map_into_debug_map(link_map* map);
+void remove_link_map_from_debug_map(link_map* map);
+void notify_gdb_of_load(link_map* map);
+void notify_gdb_of_unload(link_map* map);
+void notify_gdb_of_libraries();
+
+extern struct r_debug _r_debug;
+
+__END_DECLS
+
+#endif