495 lines
10 KiB
C
495 lines
10 KiB
C
/*
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* Copyright (C) 2006-2008 Martin Willi
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* Hochschule fuer Technik Rapperswil
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*
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* $Id$
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*/
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#ifdef HAVE_DLADDR
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# define _GNU_SOURCE
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# include <dlfcn.h>
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#endif /* HAVE_DLADDR */
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#include <stddef.h>
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#include <string.h>
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#include <stdio.h>
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#include <malloc.h>
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#include <signal.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <dlfcn.h>
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#include <unistd.h>
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#include <syslog.h>
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#include <pthread.h>
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#include <netdb.h>
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#include <printf.h>
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#include <locale.h>
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#ifdef HAVE_BACKTRACE
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# include <execinfo.h>
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#endif /* HAVE_BACKTRACE */
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#include "leak_detective.h"
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#include <library.h>
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#include <debug.h>
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typedef struct private_leak_detective_t private_leak_detective_t;
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/**
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* private data of leak_detective
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*/
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struct private_leak_detective_t {
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/**
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* public functions
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*/
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leak_detective_t public;
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};
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/**
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* Magic value which helps to detect memory corruption. Yummy!
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*/
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#define MEMORY_HEADER_MAGIC 0x7ac0be11
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/**
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* Pattern which is filled in memory before freeing it
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*/
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#define MEMORY_FREE_PATTERN 0xFF
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/**
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* Pattern which is filled in newly allocated memory
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*/
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#define MEMORY_ALLOC_PATTERN 0xEE
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static void install_hooks(void);
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static void uninstall_hooks(void);
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static void *malloc_hook(size_t, const void *);
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static void *realloc_hook(void *, size_t, const void *);
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static void free_hook(void*, const void *);
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static u_int count_malloc = 0;
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static u_int count_free = 0;
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static u_int count_realloc = 0;
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typedef struct memory_header_t memory_header_t;
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/**
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* Header which is prepended to each allocated memory block
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*/
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struct memory_header_t {
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/**
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* Magci byte which must(!) hold MEMORY_HEADER_MAGIC
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*/
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u_int32_t magic;
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/**
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* Number of bytes following after the header
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*/
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size_t bytes;
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/**
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* Stack frames at the time of allocation
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*/
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void *stack_frames[STACK_FRAMES_COUNT];
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/**
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* Number of stacks frames obtained in stack_frames
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*/
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int stack_frame_count;
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/**
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* Pointer to previous entry in linked list
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*/
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memory_header_t *previous;
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/**
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* Pointer to next entry in linked list
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*/
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memory_header_t *next;
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};
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/**
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* first mem header is just a dummy to chain
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* the others on it...
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*/
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static memory_header_t first_header = {
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magic: MEMORY_HEADER_MAGIC,
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bytes: 0,
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stack_frame_count: 0,
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previous: NULL,
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next: NULL
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};
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/**
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* standard hooks, used to temparily remove hooking
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*/
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static void *old_malloc_hook, *old_realloc_hook, *old_free_hook;
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/**
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* are the hooks currently installed?
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*/
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static bool installed = FALSE;
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/**
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* Mutex to exclusivly uninstall hooks, access heap list
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*/
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static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
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/**
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* log stack frames queried by backtrace()
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* TODO: Dump symbols of static functions. This could be done with
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* the addr2line utility or the GNU BFD Library...
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*/
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static void log_stack_frames(void **stack_frames, int stack_frame_count)
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{
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#ifdef HAVE_BACKTRACE
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char **strings;
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size_t i;
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strings = backtrace_symbols(stack_frames, stack_frame_count);
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fprintf(stderr, " dumping %d stack frame addresses\n", stack_frame_count);
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for (i = 0; i < stack_frame_count; i++)
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{
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#ifdef HAVE_DLADDR
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Dl_info info;
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/* TODO: this is quite hackish, but it works. A more proper solution
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* would execve addr2strongline and pipe the output to DBG1() */
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if (dladdr(stack_frames[i], &info))
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{
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char cmd[1024];
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void *ptr = stack_frames[i];
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if (strstr(info.dli_fname, ".so"))
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{
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ptr = (void*)(stack_frames[i] - info.dli_fbase);
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}
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snprintf(cmd, sizeof(cmd), "addr2line -e %s %p", info.dli_fname, ptr);
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if (info.dli_sname)
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{
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fprintf(stderr, " \e[33m%s\e[0m @ %p (\e[31m%s+0x%x\e[0m) [%p]\n",
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info.dli_fname, info.dli_fbase, info.dli_sname,
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stack_frames[i] - info.dli_saddr, stack_frames[i]);
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}
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else
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{
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fprintf(stderr, " \e[33m%s\e[0m @ %p [%p]\n", info.dli_fname,
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info.dli_fbase, stack_frames[i]);
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}
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fprintf(stderr, " -> \e[32m");
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system(cmd);
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fprintf(stderr, "\e[0m");
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}
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else
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#endif /* HAVE_DLADDR */
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{
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fprintf(stderr, " %s\n", strings[i]);
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}
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}
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free (strings);
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#endif /* HAVE_BACKTRACE */
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}
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/**
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* Leak report white list
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*
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* List of functions using static allocation buffers or should be suppressed
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* otherwise on leak report.
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*/
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char *whitelist[] = {
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/* pthread stuff */
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"pthread_create",
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"pthread_setspecific",
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/* glibc functions */
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"mktime",
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"tzset",
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"inet_ntoa",
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"strerror",
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"getprotobynumber",
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"getservbyport",
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"getservbyname",
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"register_printf_function",
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"syslog",
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"vsyslog",
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"getaddrinfo",
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"setlocale",
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/* ignore dlopen, as we do not dlclose to get proper leak reports */
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"dlopen",
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/* mysql functions */
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"mysql_init_character_set",
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"init_client_errs",
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"my_thread_init",
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/* fastcgi library */
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"FCGX_Init",
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/* libxml */
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"xmlInitCharEncodingHandlers",
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"xmlInitParser",
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"xmlInitParserCtxt",
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/* ClearSilver */
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"nerr_init",
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};
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/**
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* check if a stack frame contains functions listed above
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*/
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static bool is_whitelisted(void **stack_frames, int stack_frame_count)
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{
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int i, j;
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#ifdef HAVE_DLADDR
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for (i=0; i< stack_frame_count; i++)
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{
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Dl_info info;
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if (dladdr(stack_frames[i], &info) && info.dli_sname)
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{
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for (j = 0; j < sizeof(whitelist)/sizeof(char*); j++)
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{
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if (streq(info.dli_sname, whitelist[j]))
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{
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return TRUE;
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}
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}
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}
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}
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#endif /* HAVE_DLADDR */
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return FALSE;
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}
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/**
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* Report leaks at library destruction
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*/
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void report_leaks()
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{
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memory_header_t *hdr;
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int leaks = 0, whitelisted = 0;
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for (hdr = first_header.next; hdr != NULL; hdr = hdr->next)
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{
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if (is_whitelisted(hdr->stack_frames, hdr->stack_frame_count))
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{
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whitelisted++;
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}
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else
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{
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fprintf(stderr, "Leak (%d bytes at %p):\n", hdr->bytes, hdr + 1);
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/* skip the first frame, contains leak detective logic */
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log_stack_frames(hdr->stack_frames + 1, hdr->stack_frame_count - 1);
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leaks++;
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}
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}
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switch (leaks)
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{
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case 0:
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fprintf(stderr, "No leaks detected");
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break;
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case 1:
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fprintf(stderr, "One leak detected");
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break;
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default:
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fprintf(stderr, "%d leaks detected", leaks);
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break;
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}
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fprintf(stderr, ", %d suppressed by whitelist\n", whitelisted);
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}
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/**
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* Installs the malloc hooks, enables leak detection
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*/
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static void install_hooks()
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{
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if (!installed)
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{
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old_malloc_hook = __malloc_hook;
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old_realloc_hook = __realloc_hook;
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old_free_hook = __free_hook;
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__malloc_hook = malloc_hook;
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__realloc_hook = realloc_hook;
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__free_hook = free_hook;
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installed = TRUE;
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}
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}
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/**
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* Uninstalls the malloc hooks, disables leak detection
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*/
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static void uninstall_hooks()
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{
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if (installed)
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{
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__malloc_hook = old_malloc_hook;
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__free_hook = old_free_hook;
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__realloc_hook = old_realloc_hook;
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installed = FALSE;
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}
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}
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/**
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* Hook function for malloc()
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*/
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void *malloc_hook(size_t bytes, const void *caller)
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{
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memory_header_t *hdr;
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pthread_mutex_lock(&mutex);
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count_malloc++;
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uninstall_hooks();
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hdr = malloc(bytes + sizeof(memory_header_t));
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/* set to something which causes crashes */
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memset(hdr, MEMORY_ALLOC_PATTERN, bytes + sizeof(memory_header_t));
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hdr->magic = MEMORY_HEADER_MAGIC;
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hdr->bytes = bytes;
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hdr->stack_frame_count = backtrace(hdr->stack_frames, STACK_FRAMES_COUNT);
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install_hooks();
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/* insert at the beginning of the list */
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hdr->next = first_header.next;
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if (hdr->next)
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{
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hdr->next->previous = hdr;
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}
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hdr->previous = &first_header;
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first_header.next = hdr;
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pthread_mutex_unlock(&mutex);
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return hdr + 1;
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}
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/**
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* Hook function for free()
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*/
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void free_hook(void *ptr, const void *caller)
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{
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void *stack_frames[STACK_FRAMES_COUNT];
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int stack_frame_count;
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memory_header_t *hdr = ptr - sizeof(memory_header_t);
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/* allow freeing of NULL */
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if (ptr == NULL)
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{
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return;
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}
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pthread_mutex_lock(&mutex);
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count_free++;
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uninstall_hooks();
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if (hdr->magic != MEMORY_HEADER_MAGIC)
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{
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fprintf(stderr, "freeing of invalid memory (%p, MAGIC 0x%x != 0x%x):\n",
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ptr, hdr->magic, MEMORY_HEADER_MAGIC);
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stack_frame_count = backtrace(stack_frames, STACK_FRAMES_COUNT);
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log_stack_frames(stack_frames, stack_frame_count);
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install_hooks();
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pthread_mutex_unlock(&mutex);
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return;
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}
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/* remove item from list */
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if (hdr->next)
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{
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hdr->next->previous = hdr->previous;
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}
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hdr->previous->next = hdr->next;
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/* clear MAGIC, set mem to something remarkable */
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memset(hdr, MEMORY_FREE_PATTERN, hdr->bytes + sizeof(memory_header_t));
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free(hdr);
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install_hooks();
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pthread_mutex_unlock(&mutex);
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}
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/**
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* Hook function for realloc()
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*/
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void *realloc_hook(void *old, size_t bytes, const void *caller)
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{
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memory_header_t *hdr;
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void *stack_frames[STACK_FRAMES_COUNT];
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int stack_frame_count;
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/* allow reallocation of NULL */
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if (old == NULL)
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{
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return malloc_hook(bytes, caller);
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}
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hdr = old - sizeof(memory_header_t);
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pthread_mutex_lock(&mutex);
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count_realloc++;
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uninstall_hooks();
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if (hdr->magic != MEMORY_HEADER_MAGIC)
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{
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fprintf(stderr, "reallocation of invalid memory (%p):\n", old);
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stack_frame_count = backtrace(stack_frames, STACK_FRAMES_COUNT);
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log_stack_frames(stack_frames, stack_frame_count);
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install_hooks();
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pthread_mutex_unlock(&mutex);
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raise(SIGKILL);
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return NULL;
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}
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hdr = realloc(hdr, bytes + sizeof(memory_header_t));
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/* update statistics */
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hdr->bytes = bytes;
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hdr->stack_frame_count = backtrace(hdr->stack_frames, STACK_FRAMES_COUNT);
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/* update header of linked list neighbours */
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if (hdr->next)
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{
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hdr->next->previous = hdr;
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}
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hdr->previous->next = hdr;
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install_hooks();
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pthread_mutex_unlock(&mutex);
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return hdr + 1;
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}
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/**
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* Implementation of leak_detective_t.destroy
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*/
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static void destroy(private_leak_detective_t *this)
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{
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if (installed)
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{
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uninstall_hooks();
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report_leaks();
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}
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free(this);
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}
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/*
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* see header file
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*/
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leak_detective_t *leak_detective_create()
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{
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private_leak_detective_t *this = malloc_thing(private_leak_detective_t);
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this->public.destroy = (void(*)(leak_detective_t*))destroy;
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if (getenv("LEAK_DETECTIVE_DISABLE") == NULL)
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{
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install_hooks();
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}
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return &this->public;
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}
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