libc/bionic/malloc_debug_common.cpp

/*
 * 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 structures, 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 "malloc_debug_common.h"

#include <pthread.h>
#include <stdlib.h>
#include <unistd.h>

#include "private/ScopedPthreadMutexLocker.h"

// In a VM process, this is set to 1 after fork()ing out of zygote.
int gMallocLeakZygoteChild = 0;

static HashTable g_hash_table;

// Support for malloc debugging.
// Table for dispatching malloc calls, initialized with default dispatchers.
static const MallocDebug __libc_malloc_default_dispatch __attribute__((aligned(32))) = {
  Malloc(calloc),
  Malloc(free),
  Malloc(mallinfo),
  Malloc(malloc),
  Malloc(malloc_usable_size),
  Malloc(memalign),
  Malloc(posix_memalign),
  Malloc(pvalloc),
  Malloc(realloc),
  Malloc(valloc),
};

// Selector of dispatch table to use for dispatching malloc calls.
// TODO: fix http://b/15432753 and make this static again.
const MallocDebug* __libc_malloc_dispatch = &__libc_malloc_default_dispatch;

// 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.
// Note that emulator's memory allocation instrumentation is not controlled by
// libc.debug.malloc value, but rather by emulator, started with -memcheck
// option. Note also, that if emulator has started with -memcheck option,
// emulator's instrumented memory allocation will take over value saved in
// libc.debug.malloc. In other words, if emulator has started with -memcheck
// option, libc.debug.malloc value is ignored.
// Actual functionality for debug levels 1-10 is implemented in
// libc_malloc_debug_leak.so, while functionality for emulator's instrumented
// allocations is implemented in libc_malloc_debug_qemu.so and can be run inside
// the emulator only.
#if !defined(LIBC_STATIC)
static void* libc_malloc_impl_handle = NULL;
#endif


// The value of libc.debug.malloc.
#if !defined(LIBC_STATIC)
static int g_malloc_debug_level = 0;
#endif

// =============================================================================
// output functions
// =============================================================================

static int hash_entry_compare(const void* arg1, const void* arg2) {
  int result;

  const HashEntry* e1 = *static_cast<HashEntry* const*>(arg1);
  const HashEntry* e2 = *static_cast<HashEntry* const*>(arg2);

  // if one or both arg pointers are null, deal gracefully
  if (e1 == NULL) {
    result = (e2 == NULL) ? 0 : 1;
  } else if (e2 == NULL) {
    result = -1;
  } else {
    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.
    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

// =============================================================================
// Exported for use by ddms.
// =============================================================================
extern "C" 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;
  }
  *totalMemory = 0;

  ScopedPthreadMutexLocker locker(&g_hash_table.lock);
  if (g_hash_table.count == 0) {
    *info = NULL;
    *overallSize = 0;
    *infoSize = 0;
    *backtraceSize = 0;
    return;
  }

  HashEntry** list = static_cast<HashEntry**>(Malloc(malloc)(sizeof(void*) * g_hash_table.count));

  // Get the entries into an array to be sorted.
  size_t index = 0;
  for (size_t i = 0 ; i < HASHTABLE_SIZE ; ++i) {
    HashEntry* entry = g_hash_table.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(uintptr_t) * BACKTRACE_SIZE);
  *overallSize = *infoSize * g_hash_table.count;
  *backtraceSize = BACKTRACE_SIZE;

  // now get a byte array big enough for this
  *info = static_cast<uint8_t*>(Malloc(malloc)(*overallSize));
  if (*info == NULL) {
    *overallSize = 0;
    Malloc(free)(list);
    return;
  }

  qsort(list, g_hash_table.count, sizeof(void*), hash_entry_compare);

  uint8_t* head = *info;
  const size_t count = g_hash_table.count;
  for (size_t i = 0 ; i < count ; ++i) {
    HashEntry* entry = list[i];
    size_t entrySize = (sizeof(size_t) * 2) + (sizeof(uintptr_t) * entry->numEntries);
    if (entrySize < *infoSize) {
      // We're writing less than a full entry, clear out the rest.
      memset(head + entrySize, 0, *infoSize - entrySize);
    } else {
      // Make sure the amount we're copying doesn't exceed the limit.
      entrySize = *infoSize;
    }
    memcpy(head, &(entry->size), entrySize);
    head += *infoSize;
  }

  Malloc(free)(list);
}

extern "C" void free_malloc_leak_info(uint8_t* info) {
  Malloc(free)(info);
}

// =============================================================================
// Allocation functions
// =============================================================================
extern "C" void* calloc(size_t n_elements, size_t elem_size) {
  return __libc_malloc_dispatch->calloc(n_elements, elem_size);
}

extern "C" void free(void* mem) {
  __libc_malloc_dispatch->free(mem);
}

extern "C" struct mallinfo mallinfo() {
  return __libc_malloc_dispatch->mallinfo();
}

extern "C" void* malloc(size_t bytes) {
  return __libc_malloc_dispatch->malloc(bytes);
}

extern "C" size_t malloc_usable_size(const void* mem) {
  return __libc_malloc_dispatch->malloc_usable_size(mem);
}

extern "C" void* memalign(size_t alignment, size_t bytes) {
  return __libc_malloc_dispatch->memalign(alignment, bytes);
}

extern "C" int posix_memalign(void** memptr, size_t alignment, size_t size) {
  return __libc_malloc_dispatch->posix_memalign(memptr, alignment, size);
}

extern "C" void* pvalloc(size_t bytes) {
  return __libc_malloc_dispatch->pvalloc(bytes);
}

extern "C" void* realloc(void* oldMem, size_t bytes) {
  return __libc_malloc_dispatch->realloc(oldMem, bytes);
}

extern "C" void* valloc(size_t bytes) {
  return __libc_malloc_dispatch->valloc(bytes);
}

// We implement malloc debugging only in libc.so, so the code below
// must be excluded if we compile this file for static libc.a
#ifndef LIBC_STATIC
#include <sys/system_properties.h>
#include <dlfcn.h>
#include <stdio.h>
#include "private/libc_logging.h"

template<typename FunctionType>
static void InitMallocFunction(void* malloc_impl_handler, FunctionType* func, const char* prefix, const char* suffix) {
  char symbol[128];
  snprintf(symbol, sizeof(symbol), "%s_%s", prefix, suffix);
  *func = reinterpret_cast<FunctionType>(dlsym(malloc_impl_handler, symbol));
  if (*func == NULL) {
    error_log("%s: dlsym(\"%s\") failed", getprogname(), symbol);
  }
}

static void InitMalloc(void* malloc_impl_handler, MallocDebug* table, const char* prefix) {
  __libc_format_log(ANDROID_LOG_INFO, "libc", "%s: using libc.debug.malloc %d (%s)\n",
                    getprogname(), g_malloc_debug_level, prefix);

  InitMallocFunction<MallocDebugCalloc>(malloc_impl_handler, &table->calloc, prefix, "calloc");
  InitMallocFunction<MallocDebugFree>(malloc_impl_handler, &table->free, prefix, "free");
  InitMallocFunction<MallocDebugMallinfo>(malloc_impl_handler, &table->mallinfo, prefix, "mallinfo");
  InitMallocFunction<MallocDebugMalloc>(malloc_impl_handler, &table->malloc, prefix, "malloc");
  InitMallocFunction<MallocDebugMallocUsableSize>(malloc_impl_handler, &table->malloc_usable_size, prefix, "malloc_usable_size");
  InitMallocFunction<MallocDebugMemalign>(malloc_impl_handler, &table->memalign, prefix, "memalign");
  InitMallocFunction<MallocDebugPosixMemalign>(malloc_impl_handler, &table->posix_memalign, prefix, "posix_memalign");
  InitMallocFunction<MallocDebugPvalloc>(malloc_impl_handler, &table->pvalloc, prefix, "pvalloc");
  InitMallocFunction<MallocDebugRealloc>(malloc_impl_handler, &table->realloc, prefix, "realloc");
  InitMallocFunction<MallocDebugValloc>(malloc_impl_handler, &table->valloc, prefix, "valloc");
}

// Initializes memory allocation framework once per process.
static void malloc_init_impl() {
  const char* so_name = NULL;
  MallocDebugInit malloc_debug_initialize = NULL;
  unsigned int qemu_running = 0;
  unsigned int memcheck_enabled = 0;
  char env[PROP_VALUE_MAX];
  char memcheck_tracing[PROP_VALUE_MAX];
  char debug_program[PROP_VALUE_MAX];

  // Get custom malloc debug level. Note that emulator started with
  // memory checking option will have priority over debug level set in
  // libc.debug.malloc system property.
  if (__system_property_get("ro.kernel.qemu", env) && atoi(env)) {
    qemu_running = 1;
    if (__system_property_get("ro.kernel.memcheck", memcheck_tracing)) {
      if (memcheck_tracing[0] != '0') {
        // Emulator has started with memory tracing enabled. Enforce it.
        g_malloc_debug_level = 20;
        memcheck_enabled = 1;
      }
    }
  }

  // If debug level has not been set by memcheck option in the emulator,
  // lets grab it from libc.debug.malloc system property.
  if (g_malloc_debug_level == 0 && __system_property_get("libc.debug.malloc", env)) {
    g_malloc_debug_level = atoi(env);
  }

  // Debug level 0 means that we should use default allocation routines.
  if (g_malloc_debug_level == 0) {
    return;
  }

  // If libc.debug.malloc.program is set and is not a substring of progname,
  // then exit.
  if (__system_property_get("libc.debug.malloc.program", debug_program)) {
    if (!strstr(getprogname(), debug_program)) {
      return;
    }
  }

  // mksh is way too leaky. http://b/7291287.
  if (g_malloc_debug_level >= 10) {
    if (strcmp(getprogname(), "sh") == 0 || strcmp(getprogname(), "/system/bin/sh") == 0) {
      return;
    }
  }

  // Choose the appropriate .so for the requested debug level.
  switch (g_malloc_debug_level) {
    case 1:
    case 5:
    case 10:
      so_name = "libc_malloc_debug_leak.so";
      break;
    case 20:
      // Quick check: debug level 20 can only be handled in emulator.
      if (!qemu_running) {
        error_log("%s: Debug level %d can only be set in emulator\n",
                  getprogname(), g_malloc_debug_level);
        return;
      }
      // Make sure that memory checking has been enabled in emulator.
      if (!memcheck_enabled) {
        error_log("%s: Memory checking is not enabled in the emulator\n", getprogname());
        return;
      }
      so_name = "libc_malloc_debug_qemu.so";
      break;
    default:
      error_log("%s: Debug level %d is unknown\n", getprogname(), g_malloc_debug_level);
      return;
  }

  // Load .so that implements the required malloc debugging functionality.
  void* malloc_impl_handle = dlopen(so_name, RTLD_LAZY);
  if (malloc_impl_handle == NULL) {
    error_log("%s: Missing module %s required for malloc debug level %d: %s",
              getprogname(), so_name, g_malloc_debug_level, dlerror());
    return;
  }

  // Initialize malloc debugging in the loaded module.
  malloc_debug_initialize = reinterpret_cast<MallocDebugInit>(dlsym(malloc_impl_handle,
                                                                    "malloc_debug_initialize"));
  if (malloc_debug_initialize == NULL) {
    error_log("%s: Initialization routine is not found in %s\n", getprogname(), so_name);
    dlclose(malloc_impl_handle);
    return;
  }
  if (malloc_debug_initialize(&g_hash_table) == -1) {
    dlclose(malloc_impl_handle);
    return;
  }

  if (g_malloc_debug_level == 20) {
    // For memory checker we need to do extra initialization.
    typedef int (*MemCheckInit)(int, const char*);
    MemCheckInit memcheck_initialize =
      reinterpret_cast<MemCheckInit>(dlsym(malloc_impl_handle, "memcheck_initialize"));
    if (memcheck_initialize == NULL) {
      error_log("%s: memcheck_initialize routine is not found in %s\n",
                getprogname(), so_name);
      dlclose(malloc_impl_handle);
      return;
    }

    if (memcheck_initialize(MALLOC_ALIGNMENT, memcheck_tracing)) {
      dlclose(malloc_impl_handle);
      return;
    }
  }

  // No need to init the dispatch table because we can only get
  // here if debug level is 1, 5, 10, or 20.
  static MallocDebug malloc_dispatch_table __attribute__((aligned(32)));
  switch (g_malloc_debug_level) {
    case 1:
      InitMalloc(malloc_impl_handle, &malloc_dispatch_table, "leak");
      break;
    case 5:
      InitMalloc(malloc_impl_handle, &malloc_dispatch_table, "fill");
      break;
    case 10:
      InitMalloc(malloc_impl_handle, &malloc_dispatch_table, "chk");
      break;
    case 20:
      InitMalloc(malloc_impl_handle, &malloc_dispatch_table, "qemu_instrumented");
      break;
    default:
      break;
  }

  // Make sure dispatch table is initialized
  if ((malloc_dispatch_table.calloc == NULL) ||
      (malloc_dispatch_table.free == NULL) ||
      (malloc_dispatch_table.mallinfo == NULL) ||
      (malloc_dispatch_table.malloc == NULL) ||
      (malloc_dispatch_table.malloc_usable_size == NULL) ||
      (malloc_dispatch_table.memalign == NULL) ||
      (malloc_dispatch_table.posix_memalign == NULL) ||
      (malloc_dispatch_table.pvalloc == NULL) ||
      (malloc_dispatch_table.realloc == NULL) ||
      (malloc_dispatch_table.valloc == NULL)) {
    error_log("%s: some symbols for libc.debug.malloc level %d were not found (see above)",
              getprogname(), g_malloc_debug_level);
    dlclose(malloc_impl_handle);
  } else {
    __libc_malloc_dispatch = &malloc_dispatch_table;
    libc_malloc_impl_handle = malloc_impl_handle;
  }
}

static void malloc_fini_impl() {
  // Our BSD stdio implementation doesn't close the standard streams, it only flushes them.
  // And it doesn't do that until its atexit handler is run, and we run first!
  // It's great that other unclosed FILE*s show up as malloc leaks, but we need to manually
  // clean up the standard streams ourselves.
  fclose(stdin);
  fclose(stdout);
  fclose(stderr);

  if (libc_malloc_impl_handle != NULL) {
    MallocDebugFini malloc_debug_finalize =
      reinterpret_cast<MallocDebugFini>(dlsym(libc_malloc_impl_handle, "malloc_debug_finalize"));
    if (malloc_debug_finalize != NULL) {
      malloc_debug_finalize(g_malloc_debug_level);
    }
  }
}

#endif  // !LIBC_STATIC

// Initializes memory allocation framework.
// This routine is called from __libc_init routines implemented
// in libc_init_static.c and libc_init_dynamic.c files.
extern "C" __LIBC_HIDDEN__ void malloc_debug_init() {
#if !defined(LIBC_STATIC)
  static pthread_once_t malloc_init_once_ctl = PTHREAD_ONCE_INIT;
  if (pthread_once(&malloc_init_once_ctl, malloc_init_impl)) {
    error_log("Unable to initialize malloc_debug component.");
  }
#endif  // !LIBC_STATIC
}

extern "C" __LIBC_HIDDEN__ void malloc_debug_fini() {
#if !defined(LIBC_STATIC)
  static pthread_once_t malloc_fini_once_ctl = PTHREAD_ONCE_INIT;
  if (pthread_once(&malloc_fini_once_ctl, malloc_fini_impl)) {
    error_log("Unable to finalize malloc_debug component.");
  }
#endif  // !LIBC_STATIC
}