malloc.c

测试内存泄露工具

/*
 * user-level memory-allocation routines
 *
 * Copyright 2000 by Gray Watson
 *
 * This file is part of the dmalloc package.
 *
 * Permission to use, copy, modify, and distribute this software for
 * any purpose and without fee is hereby granted, provided that the
 * above copyright notice and this permission notice appear in all
 * copies, and that the name of Gray Watson not be used in advertising
 * or publicity pertaining to distribution of the document or software
 * without specific, written prior permission.
 *
 * Gray Watson makes no representations about the suitability of the
 * software described herein for any purpose.  It is provided "as is"
 * without express or implied warranty.
 *
 * The author may be contacted via http://dmalloc.com/
 *
 * $Id: malloc.c,v 1.183 2004/09/13 22:37:36 gray Exp $
 */

/*
 * This file contains the user-level calls to the memory allocation
 * routines.  It handles a lot of the miscellaneous support garbage for
 * chunk.c which is the real heap manager.
 */

#include <stdio.h>				/* for sprintf sometimes */
#if HAVE_STDLIB_H
# include <stdlib.h>				/* for atexit */
#endif
#if HAVE_STRING_H
# include <string.h>				/* for strlen */
#endif
#if HAVE_UNISTD_H
# include <unistd.h>				/* for write */
#endif

/*
 * cygwin includes
 */
#if HAVE_SYS_CYGWIN_H
# include <sys/cygwin.h>
#endif
#if HAVE_STDARG_H
# include <stdarg.h>
#endif
#if HAVE_W32API_WINDEF_H
# include <w32api/windef.h>
#endif
#if HAVE_W32API_WINBASE_H
# include <w32api/winbase.h>
#endif

#include "conf.h"				/* up here for _INCLUDE */

#if LOG_PNT_TIMEVAL
# ifdef TIMEVAL_INCLUDE
#  include TIMEVAL_INCLUDE
# endif
#else
# if HAVE_TIME /* NOT LOG_PNT_TIME */
#  ifdef TIME_INCLUDE
#   include TIME_INCLUDE
#  endif
# endif
#endif

#if LOCK_THREADS
#if HAVE_PTHREAD_H
#include <pthread.h>
#endif
#if HAVE_PTHREADS_H
#include <pthreads.h>
#endif
#endif

#if SIGNAL_OKAY && HAVE_SIGNAL_H
#include <signal.h>
#endif

#define DMALLOC_DISABLE

#include "dmalloc.h"

#include "chunk.h"
#include "compat.h"
#include "debug_tok.h"
#include "env.h"
#include "error.h"
#include "error_val.h"
#include "heap.h"
#include "dmalloc_loc.h"
#include "malloc_funcs.h"
#include "return.h"

#if LOCK_THREADS
#if IDENT_WORKS
#ident "@(#) $Information: lock-threads is enabled $"
#else
static char *information = "@(#) $Information: lock-threads is enabled $";
#endif
#endif

/* exported variables */

/* internal dmalloc error number for reference purposes only */
int		dmalloc_errno = ERROR_NONE;

/* logfile for dumping dmalloc info, DMALLOC_LOGFILE env var overrides this */
char		*dmalloc_logpath = NULL;

/* local variables */
static	int		enabled_b = 0;		/* have we started yet? */
static	int		in_alloc_b = 0;		/* can't be here twice */
static	int		do_shutdown_b = 0;	/* execute shutdown soon */
static	int		memalign_warn_b = 0;	/* memalign warning printed?*/
static	dmalloc_track_t	tracking_func = NULL;	/* memory trxn tracking func */

/* debug variables */
static	char		*start_file = NULL;	/* file to start at */
static	int		start_line = 0;		/* line to start */
static	unsigned long	start_iter = 0;		/* start after X iterations */
static	unsigned long	start_size = 0;		/* start after X bytes */
static	int		thread_lock_c = 0;	/* lock counter */

/****************************** thread locking *******************************/

#if LOCK_THREADS
#ifdef THREAD_MUTEX_T
/*
 * Define a global variable we use as a lock counter.
 *
 * NOTE: we do not use the PTHREAD_MUTEX_INITIALIZER since this
 * basically delays the pthread_mutex_init call to when
 * pthread_mutex_lock is called for the first time (at least on
 * freebsd).  Since we don't want to go recursive into the pthread
 * library when we go to lock our mutex variable, we want to force the
 * initialization to happen beforehand with a call to
 * pthread_mute_init.
 */
static THREAD_MUTEX_T dmalloc_mutex;
#else
#error We need to have THREAD_MUTEX_T defined by the configure script
#endif
#endif

/*
 * THREADS LOCKING:
 *
 * Because we need to protect for multiple threads making calls into
 * the dmalloc library at the same time, we need to initialize and use
 * a thread mutex variable.  The problem is that most thread libraries
 * uses malloc itself and do not like to go recursive.
 *
 * There are two places where we may have this problem.  One is when
 * we try to use our mutex-lock variable when pthreads is starting up
 * in a shaky state.  The thread library allocates some space, the
 * dmalloc library needs to lock its mutex variable so calls back into
 * the pthread library before it is ready for a call, and a core dump
 * is probably the result.
 *
 * We hopefully solve this by having the dmalloc library not lock
 * during the first couple of memory transactions.  The number is
 * controlled by lock-on dmalloc program environmental setting (set
 * with ``dmalloc -o X'').  You will have to play with the value.  Too
 * many will cause two threads to march into the dmalloc code at the
 * same time generating a ERROR_IN_TWICE error.  Too few and you will
 * get a core dump in the pthreads initialization code.
 *
 * The second place where we might go recursive is when we go to
 * actually initialize our mutex-lock before we can use it.  The
 * THREAD_INIT_LOCK variable (in settings.h) defines that the
 * initialization happens 2 memory transactions before the library
 * begins to use the mutex (lock-on - 2).  It we waited to initialize
 * the variable right before we used it, the pthread library might
 * want to allocate some memory for the variable causing a recursive
 * call and probably a seg-fault -- at least in OSF.  If people need
 * to have this variable also be runtime configurable or would like to
 * present an alternative default, please let me know.
 */

#if LOCK_THREADS
/*
 * mutex lock the malloc library
 */
static	void	lock_thread(void)
{
  /* we only lock if the lock-on counter has reached 0 */
  if (thread_lock_c == 0) {
#if HAVE_PTHREAD_MUTEX_LOCK
    pthread_mutex_lock(&dmalloc_mutex);
#endif
  }
}

/*
 * mutex unlock the malloc library
 */
static	void	unlock_thread(void)
{
  /* if the lock-on counter has not reached 0 then count it down */
  if (thread_lock_c > 0) {
    thread_lock_c--;
    /*
     * As we approach the time when we start mutex locking the
     * library, we need to init the mutex variable.  This sets how
     * many times before we start locking should we init the variable
     * taking in account that the init itself might generate a call
     * into the library.  Ugh.
     */
    if (thread_lock_c == THREAD_INIT_LOCK) {
#if HAVE_PTHREAD_MUTEX_INIT
      /*
       * NOTE: we do not use the PTHREAD_MUTEX_INITIALIZER since this
       * basically delays the pthread_mutex_init call to when
       * pthread_mutex_lock is called for the first time (at least on
       * freebsd).  Since we don't want to go recursive into the
       * pthread library when we go to lock our mutex variable, we
       * want to force the initialization to happen beforehand with a
       * call to pthread_mute_init.
       */
      pthread_mutex_init(&dmalloc_mutex, THREAD_LOCK_INIT_VAL);
#endif
    }
  }
  else if (thread_lock_c == 0) {
#if HAVE_PTHREAD_MUTEX_UNLOCK
    pthread_mutex_unlock(&dmalloc_mutex);
#endif
  }
}
#endif

/****************************** local utilities ******************************/

/*
 * check out a pointer to see if we were looking for it.  this should
 * be re-entrant and it may not return.
 */
static	void	check_pnt(const char *file, const int line, const void *pnt,
			  const char *label)
{
  static unsigned long	addr_c = 0;
  char			where_buf[64];
  
  if (_dmalloc_address == NULL || pnt != _dmalloc_address) {
    return;
  }
  
  addr_c++;
  dmalloc_message("address '%#lx' found in '%s' at pass %ld from '%s'",
		  (unsigned long)pnt, label, addr_c,
		  _dmalloc_chunk_desc_pnt(where_buf, sizeof(where_buf), file,
					  line));
  
  /* NOTE: if address_seen_n == 0 then never quit */
  if (_dmalloc_address_seen_n > 0 && addr_c >= _dmalloc_address_seen_n) {
    dmalloc_errno = ERROR_IS_FOUND;
    dmalloc_error("check_pnt");
  }
}

/*
 * process the values of dmalloc environ variables
 */
static	void	process_environ(const char *option_str)
{
  /*
   * we have a static here so we can store the string without getting
   * into problems
   */
  static char	options[1024];
  
  /* process the options flag */
  if (option_str == NULL) {
    options[0] = '\0';
  }
  else {
    strncpy(options, option_str, sizeof(options));
    options[sizeof(options) - 1] = '\0';
  }
  
  _dmalloc_environ_process(options, &_dmalloc_address,
			   (long *)&_dmalloc_address_seen_n, &_dmalloc_flags,
			   &_dmalloc_check_interval, &_dmalloc_lock_on,
			   &dmalloc_logpath, &start_file, &start_line,
			   &start_iter, &start_size, &_dmalloc_memory_limit);
  thread_lock_c = _dmalloc_lock_on;
  
  /* if we set the start stuff, then check-heap comes on later */
  if (start_iter > 0 || start_size > 0) {
    BIT_CLEAR(_dmalloc_flags, DEBUG_CHECK_HEAP);
  }
  
  /* indicate that we should reopen the logfile if we need to */
  _dmalloc_reopen_log();
  
#if LOCK_THREADS == 0
  /* was thread-lock-on specified but not configured? */
  if (_dmalloc_lock_on > 0) {
    dmalloc_errno = ERROR_LOCK_NOT_CONFIG;
    _dmalloc_die(0);
  }
#endif
}

/************************** startup/shutdown calls ***************************/

#if SIGNAL_OKAY
/*
 * signal catcher
 */
static	RETSIGTYPE	signal_handler(const int sig)
{
  dmalloc_message("caught signal %d", sig);
  /* if we are already inside malloc then do the shutdown later */
  if (in_alloc_b) {
    do_shutdown_b = 1;
  }
  else {
    dmalloc_shutdown();
  }
}
#endif

/*
 * startup the memory-allocation module
 */
static	int	dmalloc_startup(const char *debug_str)
{
  static int	some_up_b = 0;
  const char	*env_str;
#ifdef __CYGWIN__
  char		env_buf[256];
#endif
  
  /* have we started already? */
  if (enabled_b) {
    return 0;
  }
  
  if (! some_up_b) {
    /* set this up here so if an error occurs below, it will not try again */
    some_up_b = 1;
    
#if LOG_PNT_TIMEVAL
    GET_TIMEVAL(_dmalloc_start);
#else
#if HAVE_TIME /* NOT LOG_PNT_TIME */
    _dmalloc_start = time(NULL);
#endif
#endif
    
    /*
     * If we are running under Cygwin then getenv may not be safe.  We
     * try to use the GetEnvironmentVariableA function instead.
     */
#if defined(__CYGWIN__) && HAVE_GETENVIRONMENTVARIABLEA
    /* use this function instead of getenv */
    GetEnvironmentVariableA(OPTIONS_ENVIRON, env_buf, sizeof(env_buf));
    env_str = env_buf;
#else /* ! __CYGWIN__ */
#if GETENV_SAFE
    /* get the options flag */
    if (debug_str == NULL) {
      env_str = getenv(OPTIONS_ENVIRON);
    }
    else {
      env_str = debug_str;
    }
    
    /* process the environmental variable(s) */
    process_environ(env_str);
#endif /* GETENV_SAFE */
#endif /* ! __CYGWIN__ */
    
    /*
     * Tune the environment here.  If we have a start-file,
     * start-count, or interval enabled then make sure the check-heap
     * flag is cleared.
     */ 
    if (start_file != NULL
	|| start_iter > 0
	|| start_size > 0
	|| _dmalloc_check_interval > 0) {
      BIT_CLEAR(_dmalloc_flags, DEBUG_CHECK_HEAP);
    }
    
    /* startup heap code */
    if (! _dmalloc_heap_startup()) {
      return 0;
    }
    
    /* startup the chunk lower-level code */
    if (! _dmalloc_chunk_startup()) {
      return 0;
    }
  }
  
#if LOCK_THREADS
  if (thread_lock_c > 0) {
    return 1;
  }
#endif
  
  /*
   * We have initialized all of our code.
   *
   * NOTE: set this up here so if an error occurs below, it will not
   * try again
   */
  enabled_b = 1;
  
  /*
   * NOTE: we may go recursive below here becasue atexit or on_exit
   * may ask for memory to be allocated.  We won't worry about it and
   * will just give it to them.  We hope that atexit didn't start the
   * allocating.  Ugh.
   */
#if AUTO_SHUTDOWN
  /* NOTE: I use the else here in case some dumb systems has both */
#if HAVE_ATEXIT
  (void)atexit(dmalloc_shutdown);
#else
#if HAVE_ON_EXIT
  (void)on_exit(dmalloc_shutdown, NULL);
#endif /* HAVE_ON_EXIT */
#endif /* ! HAVE_ATEXIT */
#endif /* AUTO_SHUTDOWN */
  
#if SIGNAL_OKAY
  if (BIT_IS_SET(_dmalloc_flags, DEBUG_CATCH_SIGNALS)) {
#ifdef SIGNAL1
    (void)signal(SIGNAL1, signal_handler);
#endif
#ifdef SIGNAL2
    (void)signal(SIGNAL2, signal_handler);
#endif
#ifdef SIGNAL3
    (void)signal(SIGNAL3, signal_handler);
#endif
#ifdef SIGNAL4
    (void)signal(SIGNAL4, signal_handler);
#endif
#ifdef SIGNAL5
    (void)signal(SIGNAL5, signal_handler);
#endif
#ifdef SIGNAL6
    (void)signal(SIGNAL6, signal_handler);
#endif
  }
#endif /* SIGNAL_OKAY */
  
  return 1;
}

/*
 * static int dmalloc_in
 *
 * DESCRIPTION:
 *
 * Call to the alloc routines has been made.  Do some initialization,
 * locking, and check some debug variables.
 *
 * RETURNS:
 *
 * Success - 1
 *
 * Failure - 0
 *
 * ARGUMENTS:
 *
 * file -> File-name or return-address of the caller.
 *
 * line -> Line-number of the caller.
 *
 * check_heap_b -> Set to 1 if it is okay to check the heap.  If set
 * to 0 then the caller will check it itself or it is a non-invasive
 * call.
 */
static	int	dmalloc_in(const char *file, const int line,
			   const int check_heap_b)
{
  if (_dmalloc_aborting_b) {
    return 0;
  }
  
  /*
   * NOTE: we need to do this outside of lock to get env vars
   * otherwise our _dmalloc_lock_on variable won't be initialized and
   * the THREAD_LOCK will flip.
   */
  if (! enabled_b) {
    if (! dmalloc_startup(NULL /* no options string */)) {
      return 0;
    }
  }
  
#if LOCK_THREADS
  lock_thread();
#endif
  
  if (in_alloc_b) {
    dmalloc_errno = ERROR_IN_TWICE;
    dmalloc_error("dmalloc_in");
    /* NOTE: dmalloc_error may die already */
    _dmalloc_die(0);
    /*NOTREACHED*/
  }
  
  in_alloc_b = 1;
  
  /* increment our interval */
  _dmalloc_iter_c++;
  
  /* check start file/line specifications */
  if ((! BIT_IS_SET(_dmalloc_flags, DEBUG_CHECK_HEAP))
      && start_file != NULL
      && file != DMALLOC_DEFAULT_FILE
      && line != DMALLOC_DEFAULT_LINE
      && strcmp(start_file, file) == 0
      && (start_line == 0 || start_line == line)) {
    BIT_SET(_dmalloc_flags, DEBUG_CHECK_HEAP);
    /*
     * we disable the start file so we won't check this again and the
     * interval can go on/off
     */
    start_file = NULL;
  }
  
  /* start checking heap after X times */
  else if (start_iter > 0) {
    if (--start_iter == 0) {
      BIT_SET(_dmalloc_flags, DEBUG_CHECK_HEAP);
      /*
       * this is automatically disabled since it goes to 0 so the
       * interval can go on/off
       */
    }
  }
  
  else if (start_size > 0 && start_size >= _dmalloc_alloc_total) {
    BIT_SET(_dmalloc_flags, DEBUG_CHECK_HEAP);
    start_size = 0;
    /* disable this check so the interval can go on/off */
  }
  
  /* checking heap every X times */
  else if (_dmalloc_check_interval > 0) {
    if (_dmalloc_iter_c % _dmalloc_check_interval == 0) {
      BIT_SET(_dmalloc_flags, DEBUG_CHECK_HEAP);
    }
    else { 
      BIT_CLEAR(_dmalloc_flags, DEBUG_CHECK_HEAP);
    }
  }
  
  /* after all that, do we need to check the heap? */
  if (check_heap_b && BIT_IS_SET(_dmalloc_flags, DEBUG_CHECK_HEAP)) {
    (void)_dmalloc_chunk_heap_check();
  }
  
  return 1;
}

/*
 * Going out of the alloc routines back to user space.
 */
static	void	dmalloc_out(void)
{
  in_alloc_b = 0;
  
#if LOCK_THREADS
  unlock_thread();
#endif
  
  if (do_shutdown_b) {
    dmalloc_shutdown();
  }
}

/***************************** exported routines *****************************/

/*
 * void dmalloc_shutdown
 *
 * DESCRIPTION:
 *
 * Shutdown the dmalloc library and provide statistics if necessary.
 *
 * RETURNS:
 *
 * None.
 *
 * ARGUMENTS:
 *
 * None.
 */
void	dmalloc_shutdown(void)
{
  /* NOTE: do not generate errors for IN_TWICE here */
  
  /* if we're already in die mode leave fast and quietly */
  if (_dmalloc_aborting_b) {
    return;
  }
  
  /*
   * Make sure that the log file is open.  We do this here because we
   * might cause an allocation in the open() and don't want to go
   * recursive.
   */
  _dmalloc_open_log();
  
  /* if we've died in dmalloc somewhere then leave fast and quietly */
  if (in_alloc_b) {
    return;
  }
  
#if LOCK_THREADS
  lock_thread();
#endif
  
  /* we do it again in case the lock synced the flag to true now */
  if (in_alloc_b) {
#if LOCK_THREADS
    unlock_thread();
#endif
    return;
  }
  
  in_alloc_b = 1;
  
  /*
   * Check the heap since we are dumping info from it.  We check it
   * when check-blank is enabled do make sure all of the areas have
   * not been overwritten.  Thanks Randell.
   */
  if (BIT_IS_SET(_dmalloc_flags, DEBUG_CHECK_HEAP)
      || BIT_IS_SET(_dmalloc_flags, DEBUG_CHECK_BLANK)
      || BIT_IS_SET(_dmalloc_flags, DEBUG_CHECK_SHUTDOWN)) {
    (void)_dmalloc_chunk_heap_check();
  }
  
  /* dump some statistics to the logfile */
  if (BIT_IS_SET(_dmalloc_flags, DEBUG_LOG_STATS)) {
    _dmalloc_chunk_log_stats();
  }
  
  /* report on non-freed pointers */
  if (BIT_IS_SET(_dmalloc_flags, DEBUG_LOG_NONFREE)) {
    _dmalloc_chunk_log_changed(0, 1, 0,