Split libc_debug.so into two .so modules loaded on demand from libc.so
This change is intended to eliminate need to replace libc.so with libc_debug.so in order to enablememory allocation debugging.
This is also the first step towards implementing extended memoryallocation debugging using emulator's capabilities in monitoring memory access.
diff --git a/libc/bionic/malloc_debug_common.c b/libc/bionic/malloc_debug_common.c
new file mode 100644
index 0000000..4210915
--- /dev/null
+++ b/libc/bionic/malloc_debug_common.c
@@ -0,0 +1,432 @@
+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * Contains definition of global variables and implementation of routines
+ * that are used by malloc leak detection code and other components in
+ * the system. The trick is that some components expect these data and
+ * routines to be defined / implemented in libc.so library, regardless
+ * whether or not MALLOC_LEAK_CHECK macro is defined. To make things even
+ * more tricky, malloc leak detection code, implemented in
+ * libc_malloc_debug.so also requires access to these variables and routines
+ * (to fill allocation entry hash table, for example). So, all relevant
+ * variables and routines are defined / implemented here and exported
+ * to all, leak detection code and other components via dynamic (libc.so),
+ * or static (libc.a) linking.
+ */
+
+#include <stdlib.h>
+#include <pthread.h>
+#include <unistd.h>
+#include "dlmalloc.h"
+#include "malloc_debug_common.h"
+
+/*
+ * In a VM process, this is set to 1 after fork()ing out of zygote.
+ */
+int gMallocLeakZygoteChild = 0;
+
+pthread_mutex_t gAllocationsMutex = PTHREAD_MUTEX_INITIALIZER;
+HashTable gHashTable;
+
+// =============================================================================
+// output functions
+// =============================================================================
+
+static int hash_entry_compare(const void* arg1, const void* arg2)
+{
+ HashEntry* e1 = *(HashEntry**)arg1;
+ HashEntry* e2 = *(HashEntry**)arg2;
+
+ size_t nbAlloc1 = e1->allocations;
+ size_t nbAlloc2 = e2->allocations;
+ size_t size1 = e1->size & ~SIZE_FLAG_MASK;
+ size_t size2 = e2->size & ~SIZE_FLAG_MASK;
+ size_t alloc1 = nbAlloc1 * size1;
+ size_t alloc2 = nbAlloc2 * size2;
+
+ // sort in descending order by:
+ // 1) total size
+ // 2) number of allocations
+ //
+ // This is used for sorting, not determination of equality, so we don't
+ // need to compare the bit flags.
+ int result;
+ if (alloc1 > alloc2) {
+ result = -1;
+ } else if (alloc1 < alloc2) {
+ result = 1;
+ } else {
+ if (nbAlloc1 > nbAlloc2) {
+ result = -1;
+ } else if (nbAlloc1 < nbAlloc2) {
+ result = 1;
+ } else {
+ result = 0;
+ }
+ }
+ return result;
+}
+
+/*
+ * Retrieve native heap information.
+ *
+ * "*info" is set to a buffer we allocate
+ * "*overallSize" is set to the size of the "info" buffer
+ * "*infoSize" is set to the size of a single entry
+ * "*totalMemory" is set to the sum of all allocations we're tracking; does
+ * not include heap overhead
+ * "*backtraceSize" is set to the maximum number of entries in the back trace
+ */
+void get_malloc_leak_info(uint8_t** info, size_t* overallSize,
+ size_t* infoSize, size_t* totalMemory, size_t* backtraceSize)
+{
+ // don't do anything if we have invalid arguments
+ if (info == NULL || overallSize == NULL || infoSize == NULL ||
+ totalMemory == NULL || backtraceSize == NULL) {
+ return;
+ }
+
+ pthread_mutex_lock(&gAllocationsMutex);
+
+ if (gHashTable.count == 0) {
+ *info = NULL;
+ *overallSize = 0;
+ *infoSize = 0;
+ *totalMemory = 0;
+ *backtraceSize = 0;
+ goto done;
+ }
+
+ void** list = (void**)dlmalloc(sizeof(void*) * gHashTable.count);
+
+ // get the entries into an array to be sorted
+ int index = 0;
+ int i;
+ for (i = 0 ; i < HASHTABLE_SIZE ; i++) {
+ HashEntry* entry = gHashTable.slots[i];
+ while (entry != NULL) {
+ list[index] = entry;
+ *totalMemory = *totalMemory +
+ ((entry->size & ~SIZE_FLAG_MASK) * entry->allocations);
+ index++;
+ entry = entry->next;
+ }
+ }
+
+ // XXX: the protocol doesn't allow variable size for the stack trace (yet)
+ *infoSize = (sizeof(size_t) * 2) + (sizeof(intptr_t) * BACKTRACE_SIZE);
+ *overallSize = *infoSize * gHashTable.count;
+ *backtraceSize = BACKTRACE_SIZE;
+
+ // now get A byte array big enough for this
+ *info = (uint8_t*)dlmalloc(*overallSize);
+
+ if (*info == NULL) {
+ *overallSize = 0;
+ goto done;
+ }
+
+ qsort((void*)list, gHashTable.count, sizeof(void*), hash_entry_compare);
+
+ uint8_t* head = *info;
+ const int count = gHashTable.count;
+ for (i = 0 ; i < count ; i++) {
+ HashEntry* entry = list[i];
+ size_t entrySize = (sizeof(size_t) * 2) + (sizeof(intptr_t) * entry->numEntries);
+ if (entrySize < *infoSize) {
+ /* we're writing less than a full entry, clear out the rest */
+ /* TODO: only clear out the part we're not overwriting? */
+ memset(head, 0, *infoSize);
+ } else {
+ /* make sure the amount we're copying doesn't exceed the limit */
+ entrySize = *infoSize;
+ }
+ memcpy(head, &(entry->size), entrySize);
+ head += *infoSize;
+ }
+
+ dlfree(list);
+
+done:
+ pthread_mutex_unlock(&gAllocationsMutex);
+}
+
+void free_malloc_leak_info(uint8_t* info)
+{
+ dlfree(info);
+}
+
+struct mallinfo mallinfo()
+{
+ return dlmallinfo();
+}
+
+void* valloc(size_t bytes) {
+ /* assume page size of 4096 bytes */
+ return memalign( getpagesize(), bytes );
+}
+
+/* Support for malloc debugging.
+ * Note that if USE_DL_PREFIX is not defined, it's assumed that memory
+ * allocation routines are implemented somewhere else, so all our custom
+ * malloc routines should not be compiled at all.
+ */
+#ifdef USE_DL_PREFIX
+
+/* Table for dispatching malloc calls, initialized with default dispatchers. */
+const MallocDebug __libc_malloc_default_dispatch __attribute__((aligned(32))) =
+{
+ dlmalloc, dlfree, dlcalloc, dlrealloc, dlmemalign
+};
+
+/* Selector of dispatch table to use for dispatching malloc calls. */
+const MallocDebug* __libc_malloc_dispatch = &__libc_malloc_default_dispatch;
+
+void* malloc(size_t bytes) {
+ return __libc_malloc_dispatch->malloc(bytes);
+}
+void free(void* mem) {
+ __libc_malloc_dispatch->free(mem);
+}
+void* calloc(size_t n_elements, size_t elem_size) {
+ return __libc_malloc_dispatch->calloc(n_elements, elem_size);
+}
+void* realloc(void* oldMem, size_t bytes) {
+ return __libc_malloc_dispatch->realloc(oldMem, bytes);
+}
+void* memalign(size_t alignment, size_t bytes) {
+ return __libc_malloc_dispatch->memalign(alignment, bytes);
+}
+
+/* We implement malloc debugging only in libc.so, so code bellow
+ * must be excluded if we compile this file for static libc.a
+ */
+#ifndef LIBC_STATIC
+#include <sys/system_properties.h>
+#include <dlfcn.h>
+#include "logd.h"
+
+// =============================================================================
+// log functions
+// =============================================================================
+
+#define debug_log(format, ...) \
+ __libc_android_log_print(ANDROID_LOG_DEBUG, "libc", (format), ##__VA_ARGS__ )
+#define error_log(format, ...) \
+ __libc_android_log_print(ANDROID_LOG_ERROR, "libc", (format), ##__VA_ARGS__ )
+#define info_log(format, ...) \
+ __libc_android_log_print(ANDROID_LOG_INFO, "libc", (format), ##__VA_ARGS__ )
+
+/* Table for dispatching malloc calls, depending on environment. */
+static MallocDebug gMallocUse __attribute__((aligned(32))) = {
+ dlmalloc, dlfree, dlcalloc, dlrealloc, dlmemalign
+};
+
+extern char* __progname;
+
+/* Handle to shared library where actual memory allocation is implemented.
+ * This library is loaded and memory allocation calls are redirected there
+ * when libc.debug.malloc environment variable contains value other than
+ * zero:
+ * 1 - For memory leak detections.
+ * 5 - For filling allocated / freed memory with patterns defined by
+ * CHK_SENTINEL_VALUE, and CHK_FILL_FREE macros.
+ * 10 - For adding pre-, and post- allocation stubs in order to detect
+ * buffer overruns.
+ * 20 - For enabling emulator memory allocation instrumentation detecting
+ * memory leaks and buffer overruns.
+ * Actual functionality for debug levels 1-10 is implemented in
+ * libc_malloc_debug_leak.so, while functionality for debug level 20 is
+ * implemented in libc_malloc_debug_qemu.so and can be run inside the
+ * emulator only.
+ */
+static void* libc_malloc_impl_handle = NULL;
+
+/* Initializes memory allocation framework once per process. */
+static void malloc_init_impl(void)
+{
+ const char* so_name = NULL;
+ unsigned int debug_level = 0;
+ unsigned int qemu_running = 0;
+ int len;
+ char env[PROP_VALUE_MAX];
+
+ // Get custom malloc debug level.
+ len = __system_property_get("libc.debug.malloc", env);
+ if (len) {
+ debug_level = atoi(env);
+ }
+
+ /* Debug level 0 means that we should use dlxxx allocation
+ * routines (default).
+ */
+ if (!debug_level) {
+ return;
+ }
+
+ // Get emulator running status.
+ len = __system_property_get("ro.kernel.qemu", env);
+ if (len) {
+ qemu_running = atoi(env);
+ }
+
+ // Lets see which .so must be loaded for the requested debug level
+ switch (debug_level) {
+ case 1:
+ case 5:
+ case 10:
+ so_name = "/system/lib/libc_malloc_debug_leak.so";
+ break;
+ case 20:
+ // Quick check: debug level 20 can only be handled in emulator
+ if (!qemu_running) {
+ info_log("%s: Debug level %d can only be set in emulator\n",
+ __progname, debug_level);
+ return;
+ }
+ so_name = "/system/lib/libc_malloc_debug_qemu.so";
+ break;
+ default:
+ info_log("%s: Debug level %d is unknown\n",
+ __progname, debug_level);
+ return;
+ }
+
+ // Load .so that implements the required malloc debugging functionality.
+ libc_malloc_impl_handle = dlopen(so_name, RTLD_LAZY);
+ if (libc_malloc_impl_handle == NULL) {
+ error_log("%s: Missing module %s required for malloc debug level %d\n",
+ __progname, so_name, debug_level);
+ return;
+ }
+
+ // Initialize malloc dispatch table with appropriate routines.
+ switch (debug_level) {
+ case 1:
+ __libc_android_log_print(ANDROID_LOG_INFO, "libc",
+ "%s using MALLOC_DEBUG = %d (leak checker)\n",
+ __progname, debug_level);
+ gMallocUse.malloc =
+ dlsym(libc_malloc_impl_handle, "leak_malloc");
+ gMallocUse.free =
+ dlsym(libc_malloc_impl_handle, "leak_free");
+ gMallocUse.calloc =
+ dlsym(libc_malloc_impl_handle, "leak_calloc");
+ gMallocUse.realloc =
+ dlsym(libc_malloc_impl_handle, "leak_realloc");
+ gMallocUse.memalign =
+ dlsym(libc_malloc_impl_handle, "leak_memalign");
+ break;
+ case 5:
+ __libc_android_log_print(ANDROID_LOG_INFO, "libc",
+ "%s using MALLOC_DEBUG = %d (fill)\n",
+ __progname, debug_level);
+ gMallocUse.malloc =
+ dlsym(libc_malloc_impl_handle, "fill_malloc");
+ gMallocUse.free =
+ dlsym(libc_malloc_impl_handle, "fill_free");
+ gMallocUse.calloc = dlcalloc;
+ gMallocUse.realloc =
+ dlsym(libc_malloc_impl_handle, "fill_realloc");
+ gMallocUse.memalign =
+ dlsym(libc_malloc_impl_handle, "fill_memalign");
+ break;
+ case 10:
+ __libc_android_log_print(ANDROID_LOG_INFO, "libc",
+ "%s using MALLOC_DEBUG = %d (sentinels, fill)\n",
+ __progname, debug_level);
+ gMallocUse.malloc =
+ dlsym(libc_malloc_impl_handle, "chk_malloc");
+ gMallocUse.free =
+ dlsym(libc_malloc_impl_handle, "chk_free");
+ gMallocUse.calloc =
+ dlsym(libc_malloc_impl_handle, "chk_calloc");
+ gMallocUse.realloc =
+ dlsym(libc_malloc_impl_handle, "chk_realloc");
+ gMallocUse.memalign =
+ dlsym(libc_malloc_impl_handle, "chk_memalign");
+ break;
+ case 20:
+ __libc_android_log_print(ANDROID_LOG_INFO, "libc",
+ "%s using MALLOC_DEBUG = %d (instrumented for emulator)\n",
+ __progname, debug_level);
+ gMallocUse.malloc =
+ dlsym(libc_malloc_impl_handle, "qemu_instrumented_malloc");
+ gMallocUse.free =
+ dlsym(libc_malloc_impl_handle, "qemu_instrumented_free");
+ gMallocUse.calloc =
+ dlsym(libc_malloc_impl_handle, "qemu_instrumented_calloc");
+ gMallocUse.realloc =
+ dlsym(libc_malloc_impl_handle, "qemu_instrumented_realloc");
+ gMallocUse.memalign =
+ dlsym(libc_malloc_impl_handle, "qemu_instrumented_memalign");
+ break;
+ default:
+ break;
+ }
+
+ // Make sure dispatch table is initialized
+ if ((gMallocUse.malloc == NULL) ||
+ (gMallocUse.free == NULL) ||
+ (gMallocUse.calloc == NULL) ||
+ (gMallocUse.realloc == NULL) ||
+ (gMallocUse.memalign == NULL)) {
+ error_log("%s: Cannot initialize malloc dispatch table for debug level"
+ " %d: %p, %p, %p, %p, %p\n",
+ __progname, debug_level,
+ gMallocUse.malloc, gMallocUse.free,
+ gMallocUse.calloc, gMallocUse.realloc,
+ gMallocUse.memalign);
+ dlclose(libc_malloc_impl_handle);
+ libc_malloc_impl_handle = NULL;
+ } else {
+ __libc_malloc_dispatch = &gMallocUse;
+ }
+}
+
+static pthread_once_t malloc_init_once_ctl = PTHREAD_ONCE_INIT;
+
+#endif // !LIBC_STATIC
+#endif // USE_DL_PREFIX
+
+/* Initializes memory allocation framework.
+ * This routine is called from __libc_init routines implemented
+ * in libc_init_static.c and libc_init_dynamic.c files.
+ */
+void malloc_debug_init(void)
+{
+ /* We need to initialize malloc iff we impelement here custom
+ * malloc routines (i.e. USE_DL_PREFIX is defined) for libc.so
+ */
+#if defined(USE_DL_PREFIX) && !defined(LIBC_STATIC)
+ if (pthread_once(&malloc_init_once_ctl, malloc_init_impl)) {
+ error_log("Unable to initialize malloc_debug component.");
+ }
+#endif // USE_DL_PREFIX && !LIBC_STATIC
+}