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_leak.c b/libc/bionic/malloc_debug_leak.c
new file mode 100644
index 0000000..7b8822c
--- /dev/null
+++ b/libc/bionic/malloc_debug_leak.c
@@ -0,0 +1,631 @@
+/*
+ * Copyright (C) 2008 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.
+ */
+#include <errno.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <stddef.h>
+#include <stdarg.h>
+#include <fcntl.h>
+#include <unwind.h>
+#include <dlfcn.h>
+
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/select.h>
+#include <sys/types.h>
+#include <sys/system_properties.h>
+
+#include "dlmalloc.h"
+#include "logd.h"
+#include "malloc_debug_common.h"
+
+// This file should be included into the build only when
+// MALLOC_LEAK_CHECK, or MALLOC_QEMU_INSTRUMENT, or both
+// macros are defined.
+#ifndef MALLOC_LEAK_CHECK
+#error MALLOC_LEAK_CHECK is not defined.
+#endif // !MALLOC_LEAK_CHECK
+
+// Global variables defined in malloc_debug_common.c
+extern int gMallocLeakZygoteChild;
+extern pthread_mutex_t gAllocationsMutex;
+extern HashTable gHashTable;
+extern const MallocDebug __libc_malloc_default_dispatch;
+extern const MallocDebug* __libc_malloc_dispatch;
+
+// =============================================================================
+// log functions
+// =============================================================================
+
+#define debug_log(format, ...) \
+ __libc_android_log_print(ANDROID_LOG_DEBUG, "malloc_leak_check", (format), ##__VA_ARGS__ )
+#define error_log(format, ...) \
+ __libc_android_log_print(ANDROID_LOG_ERROR, "malloc_leak_check", (format), ##__VA_ARGS__ )
+#define info_log(format, ...) \
+ __libc_android_log_print(ANDROID_LOG_INFO, "malloc_leak_check", (format), ##__VA_ARGS__ )
+
+static int gTrapOnError = 1;
+
+#define MALLOC_ALIGNMENT 8
+#define GUARD 0x48151642
+#define DEBUG 0
+
+// =============================================================================
+// Structures
+// =============================================================================
+typedef struct AllocationEntry AllocationEntry;
+struct AllocationEntry {
+ HashEntry* entry;
+ uint32_t guard;
+};
+
+
+// =============================================================================
+// Hash Table functions
+// =============================================================================
+static uint32_t get_hash(intptr_t* backtrace, size_t numEntries)
+{
+ if (backtrace == NULL) return 0;
+
+ int hash = 0;
+ size_t i;
+ for (i = 0 ; i < numEntries ; i++) {
+ hash = (hash * 33) + (backtrace[i] >> 2);
+ }
+
+ return hash;
+}
+
+static HashEntry* find_entry(HashTable* table, int slot,
+ intptr_t* backtrace, size_t numEntries, size_t size)
+{
+ HashEntry* entry = table->slots[slot];
+ while (entry != NULL) {
+ //debug_log("backtrace: %p, entry: %p entry->backtrace: %p\n",
+ // backtrace, entry, (entry != NULL) ? entry->backtrace : NULL);
+ /*
+ * See if the entry matches exactly. We compare the "size" field,
+ * including the flag bits.
+ */
+ if (entry->size == size && entry->numEntries == numEntries &&
+ !memcmp(backtrace, entry->backtrace, numEntries * sizeof(intptr_t))) {
+ return entry;
+ }
+
+ entry = entry->next;
+ }
+
+ return NULL;
+}
+
+static HashEntry* record_backtrace(intptr_t* backtrace, size_t numEntries, size_t size)
+{
+ size_t hash = get_hash(backtrace, numEntries);
+ size_t slot = hash % HASHTABLE_SIZE;
+
+ if (size & SIZE_FLAG_MASK) {
+ debug_log("malloc_debug: allocation %zx exceeds bit width\n", size);
+ abort();
+ }
+
+ if (gMallocLeakZygoteChild)
+ size |= SIZE_FLAG_ZYGOTE_CHILD;
+
+ HashEntry* entry = find_entry(&gHashTable, slot, backtrace, numEntries, size);
+
+ if (entry != NULL) {
+ entry->allocations++;
+ } else {
+ // create a new entry
+ entry = (HashEntry*)dlmalloc(sizeof(HashEntry) + numEntries*sizeof(intptr_t));
+ entry->allocations = 1;
+ entry->slot = slot;
+ entry->prev = NULL;
+ entry->next = gHashTable.slots[slot];
+ entry->numEntries = numEntries;
+ entry->size = size;
+
+ memcpy(entry->backtrace, backtrace, numEntries * sizeof(intptr_t));
+
+ gHashTable.slots[slot] = entry;
+
+ if (entry->next != NULL) {
+ entry->next->prev = entry;
+ }
+
+ // we just added an entry, increase the size of the hashtable
+ gHashTable.count++;
+ }
+
+ return entry;
+}
+
+static int is_valid_entry(HashEntry* entry)
+{
+ if (entry != NULL) {
+ int i;
+ for (i = 0 ; i < HASHTABLE_SIZE ; i++) {
+ HashEntry* e1 = gHashTable.slots[i];
+
+ while (e1 != NULL) {
+ if (e1 == entry) {
+ return 1;
+ }
+
+ e1 = e1->next;
+ }
+ }
+ }
+
+ return 0;
+}
+
+static void remove_entry(HashEntry* entry)
+{
+ HashEntry* prev = entry->prev;
+ HashEntry* next = entry->next;
+
+ if (prev != NULL) entry->prev->next = next;
+ if (next != NULL) entry->next->prev = prev;
+
+ if (prev == NULL) {
+ // we are the head of the list. set the head to be next
+ gHashTable.slots[entry->slot] = entry->next;
+ }
+
+ // we just removed and entry, decrease the size of the hashtable
+ gHashTable.count--;
+}
+
+
+// =============================================================================
+// stack trace functions
+// =============================================================================
+
+typedef struct
+{
+ size_t count;
+ intptr_t* addrs;
+} stack_crawl_state_t;
+
+
+/* depends how the system includes define this */
+#ifdef HAVE_UNWIND_CONTEXT_STRUCT
+typedef struct _Unwind_Context __unwind_context;
+#else
+typedef _Unwind_Context __unwind_context;
+#endif
+
+static _Unwind_Reason_Code trace_function(__unwind_context *context, void *arg)
+{
+ stack_crawl_state_t* state = (stack_crawl_state_t*)arg;
+ if (state->count) {
+ intptr_t ip = (intptr_t)_Unwind_GetIP(context);
+ if (ip) {
+ state->addrs[0] = ip;
+ state->addrs++;
+ state->count--;
+ return _URC_NO_REASON;
+ }
+ }
+ /*
+ * If we run out of space to record the address or 0 has been seen, stop
+ * unwinding the stack.
+ */
+ return _URC_END_OF_STACK;
+}
+
+static inline
+int get_backtrace(intptr_t* addrs, size_t max_entries)
+{
+ stack_crawl_state_t state;
+ state.count = max_entries;
+ state.addrs = (intptr_t*)addrs;
+ _Unwind_Backtrace(trace_function, (void*)&state);
+ return max_entries - state.count;
+}
+
+// =============================================================================
+// malloc check functions
+// =============================================================================
+
+#define CHK_FILL_FREE 0xef
+#define CHK_SENTINEL_VALUE 0xeb
+#define CHK_SENTINEL_HEAD_SIZE 16
+#define CHK_SENTINEL_TAIL_SIZE 16
+#define CHK_OVERHEAD_SIZE ( CHK_SENTINEL_HEAD_SIZE + \
+ CHK_SENTINEL_TAIL_SIZE + \
+ sizeof(size_t) )
+
+static void dump_stack_trace()
+{
+ intptr_t addrs[20];
+ int c = get_backtrace(addrs, 20);
+ char buf[16];
+ char tmp[16*20];
+ int i;
+
+ tmp[0] = 0; // Need to initialize tmp[0] for the first strcat
+ for (i=0 ; i<c; i++) {
+ snprintf(buf, sizeof buf, "%2d: %08x\n", i, addrs[i]);
+ strlcat(tmp, buf, sizeof tmp);
+ }
+ __libc_android_log_print(ANDROID_LOG_ERROR, "libc", "call stack:\n%s", tmp);
+}
+
+static int is_valid_malloc_pointer(void* addr)
+{
+ return 1;
+}
+
+static void assert_log_message(const char* format, ...)
+{
+ va_list args;
+
+ pthread_mutex_lock(&gAllocationsMutex);
+ {
+ const MallocDebug* current_dispatch = __libc_malloc_dispatch;
+ __libc_malloc_dispatch = &__libc_malloc_default_dispatch;
+ va_start(args, format);
+ __libc_android_log_vprint(ANDROID_LOG_ERROR, "libc",
+ format, args);
+ va_end(args);
+ dump_stack_trace();
+ if (gTrapOnError) {
+ __builtin_trap();
+ }
+ __libc_malloc_dispatch = current_dispatch;
+ }
+ pthread_mutex_unlock(&gAllocationsMutex);
+}
+
+static void assert_valid_malloc_pointer(void* mem)
+{
+ if (mem && !is_valid_malloc_pointer(mem)) {
+ assert_log_message(
+ "*** MALLOC CHECK: buffer %p, is not a valid "
+ "malloc pointer (are you mixing up new/delete "
+ "and malloc/free?)", mem);
+ }
+}
+
+/* Check that a given address corresponds to a guarded block,
+ * and returns its original allocation size in '*allocated'.
+ * 'func' is the capitalized name of the caller function.
+ * Returns 0 on success, or -1 on failure.
+ * NOTE: Does not return if gTrapOnError is set.
+ */
+static int chk_mem_check(void* mem,
+ size_t* allocated,
+ const char* func)
+{
+ char* buffer;
+ size_t offset, bytes;
+ int i;
+ char* buf;
+
+ /* first check the bytes in the sentinel header */
+ buf = (char*)mem - CHK_SENTINEL_HEAD_SIZE;
+ for (i=0 ; i<CHK_SENTINEL_HEAD_SIZE ; i++) {
+ if (buf[i] != CHK_SENTINEL_VALUE) {
+ assert_log_message(
+ "*** %s CHECK: buffer %p "
+ "corrupted %d bytes before allocation",
+ func, mem, CHK_SENTINEL_HEAD_SIZE-i);
+ return -1;
+ }
+ }
+
+ /* then the ones in the sentinel trailer */
+ buffer = (char*)mem - CHK_SENTINEL_HEAD_SIZE;
+ offset = dlmalloc_usable_size(buffer) - sizeof(size_t);
+ bytes = *(size_t *)(buffer + offset);
+
+ buf = (char*)mem + bytes;
+ for (i=CHK_SENTINEL_TAIL_SIZE-1 ; i>=0 ; i--) {
+ if (buf[i] != CHK_SENTINEL_VALUE) {
+ assert_log_message(
+ "*** %s CHECK: buffer %p, size=%lu, "
+ "corrupted %d bytes after allocation",
+ func, buffer, bytes, i+1);
+ return -1;
+ }
+ }
+
+ *allocated = bytes;
+ return 0;
+}
+
+
+void* chk_malloc(size_t bytes)
+{
+ char* buffer = (char*)dlmalloc(bytes + CHK_OVERHEAD_SIZE);
+ if (buffer) {
+ memset(buffer, CHK_SENTINEL_VALUE, bytes + CHK_OVERHEAD_SIZE);
+ size_t offset = dlmalloc_usable_size(buffer) - sizeof(size_t);
+ *(size_t *)(buffer + offset) = bytes;
+ buffer += CHK_SENTINEL_HEAD_SIZE;
+ }
+ return buffer;
+}
+
+void chk_free(void* mem)
+{
+ assert_valid_malloc_pointer(mem);
+ if (mem) {
+ size_t size;
+ char* buffer;
+
+ if (chk_mem_check(mem, &size, "FREE") == 0) {
+ buffer = (char*)mem - CHK_SENTINEL_HEAD_SIZE;
+ memset(buffer, CHK_FILL_FREE, size + CHK_OVERHEAD_SIZE);
+ dlfree(buffer);
+ }
+ }
+}
+
+void* chk_calloc(size_t n_elements, size_t elem_size)
+{
+ size_t size;
+ void* ptr;
+
+ /* Fail on overflow - just to be safe even though this code runs only
+ * within the debugging C library, not the production one */
+ if (n_elements && MAX_SIZE_T / n_elements < elem_size) {
+ return NULL;
+ }
+ size = n_elements * elem_size;
+ ptr = chk_malloc(size);
+ if (ptr != NULL) {
+ memset(ptr, 0, size);
+ }
+ return ptr;
+}
+
+void* chk_realloc(void* mem, size_t bytes)
+{
+ char* buffer;
+ int ret;
+ size_t old_bytes = 0;
+
+ assert_valid_malloc_pointer(mem);
+
+ if (mem != NULL && chk_mem_check(mem, &old_bytes, "REALLOC") < 0)
+ return NULL;
+
+ char* new_buffer = chk_malloc(bytes);
+ if (mem == NULL) {
+ return new_buffer;
+ }
+
+ if (new_buffer) {
+ size_t size = (bytes < old_bytes)?(bytes):(old_bytes);
+ memcpy(new_buffer, mem, size);
+ chk_free(mem);
+ }
+
+ return new_buffer;
+}
+
+void* chk_memalign(size_t alignment, size_t bytes)
+{
+ // XXX: it's better to use malloc, than being wrong
+ return chk_malloc(bytes);
+}
+
+// =============================================================================
+// malloc fill functions
+// =============================================================================
+
+void* fill_malloc(size_t bytes)
+{
+ void* buffer = dlmalloc(bytes);
+ if (buffer) {
+ memset(buffer, CHK_SENTINEL_VALUE, bytes);
+ }
+ return buffer;
+}
+
+void fill_free(void* mem)
+{
+ size_t bytes = dlmalloc_usable_size(mem);
+ memset(mem, CHK_FILL_FREE, bytes);
+ dlfree(mem);
+}
+
+void* fill_realloc(void* mem, size_t bytes)
+{
+ void* buffer = fill_malloc(bytes);
+ if (mem == NULL) {
+ return buffer;
+ }
+ if (buffer) {
+ size_t old_size = dlmalloc_usable_size(mem);
+ size_t size = (bytes < old_size)?(bytes):(old_size);
+ memcpy(buffer, mem, size);
+ fill_free(mem);
+ }
+ return buffer;
+}
+
+void* fill_memalign(size_t alignment, size_t bytes)
+{
+ void* buffer = dlmemalign(alignment, bytes);
+ if (buffer) {
+ memset(buffer, CHK_SENTINEL_VALUE, bytes);
+ }
+ return buffer;
+}
+
+// =============================================================================
+// malloc leak functions
+// =============================================================================
+
+#define MEMALIGN_GUARD ((void*)0xA1A41520)
+
+void* leak_malloc(size_t bytes)
+{
+ // allocate enough space infront of the allocation to store the pointer for
+ // the alloc structure. This will making free'ing the structer really fast!
+
+ // 1. allocate enough memory and include our header
+ // 2. set the base pointer to be right after our header
+
+ void* base = dlmalloc(bytes + sizeof(AllocationEntry));
+ if (base != NULL) {
+ pthread_mutex_lock(&gAllocationsMutex);
+
+ intptr_t backtrace[BACKTRACE_SIZE];
+ size_t numEntries = get_backtrace(backtrace, BACKTRACE_SIZE);
+
+ AllocationEntry* header = (AllocationEntry*)base;
+ header->entry = record_backtrace(backtrace, numEntries, bytes);
+ header->guard = GUARD;
+
+ // now increment base to point to after our header.
+ // this should just work since our header is 8 bytes.
+ base = (AllocationEntry*)base + 1;
+
+ pthread_mutex_unlock(&gAllocationsMutex);
+ }
+
+ return base;
+}
+
+void leak_free(void* mem)
+{
+ if (mem != NULL) {
+ pthread_mutex_lock(&gAllocationsMutex);
+
+ // check the guard to make sure it is valid
+ AllocationEntry* header = (AllocationEntry*)mem - 1;
+
+ if (header->guard != GUARD) {
+ // could be a memaligned block
+ if (((void**)mem)[-1] == MEMALIGN_GUARD) {
+ mem = ((void**)mem)[-2];
+ header = (AllocationEntry*)mem - 1;
+ }
+ }
+
+ if (header->guard == GUARD || is_valid_entry(header->entry)) {
+ // decrement the allocations
+ HashEntry* entry = header->entry;
+ entry->allocations--;
+ if (entry->allocations <= 0) {
+ remove_entry(entry);
+ dlfree(entry);
+ }
+
+ // now free the memory!
+ dlfree(header);
+ } else {
+ debug_log("WARNING bad header guard: '0x%x'! and invalid entry: %p\n",
+ header->guard, header->entry);
+ }
+
+ pthread_mutex_unlock(&gAllocationsMutex);
+ }
+}
+
+void* leak_calloc(size_t n_elements, size_t elem_size)
+{
+ size_t size;
+ void* ptr;
+
+ /* Fail on overflow - just to be safe even though this code runs only
+ * within the debugging C library, not the production one */
+ if (n_elements && MAX_SIZE_T / n_elements < elem_size) {
+ return NULL;
+ }
+ size = n_elements * elem_size;
+ ptr = leak_malloc(size);
+ if (ptr != NULL) {
+ memset(ptr, 0, size);
+ }
+ return ptr;
+}
+
+void* leak_realloc(void* oldMem, size_t bytes)
+{
+ if (oldMem == NULL) {
+ return leak_malloc(bytes);
+ }
+ void* newMem = NULL;
+ AllocationEntry* header = (AllocationEntry*)oldMem - 1;
+ if (header && header->guard == GUARD) {
+ size_t oldSize = header->entry->size & ~SIZE_FLAG_MASK;
+ newMem = leak_malloc(bytes);
+ if (newMem != NULL) {
+ size_t copySize = (oldSize <= bytes) ? oldSize : bytes;
+ memcpy(newMem, oldMem, copySize);
+ leak_free(oldMem);
+ }
+ } else {
+ newMem = dlrealloc(oldMem, bytes);
+ }
+ return newMem;
+}
+
+void* leak_memalign(size_t alignment, size_t bytes)
+{
+ // we can just use malloc
+ if (alignment <= MALLOC_ALIGNMENT)
+ return leak_malloc(bytes);
+
+ // need to make sure it's a power of two
+ if (alignment & (alignment-1))
+ alignment = 1L << (31 - __builtin_clz(alignment));
+
+ // here, aligment is at least MALLOC_ALIGNMENT<<1 bytes
+ // we will align by at least MALLOC_ALIGNMENT bytes
+ // and at most alignment-MALLOC_ALIGNMENT bytes
+ size_t size = (alignment-MALLOC_ALIGNMENT) + bytes;
+ void* base = leak_malloc(size);
+ if (base != NULL) {
+ intptr_t ptr = (intptr_t)base;
+ if ((ptr % alignment) == 0)
+ return base;
+
+ // align the pointer
+ ptr += ((-ptr) % alignment);
+
+ // there is always enough space for the base pointer and the guard
+ ((void**)ptr)[-1] = MEMALIGN_GUARD;
+ ((void**)ptr)[-2] = base;
+
+ return (void*)ptr;
+ }
+ return base;
+}