utils.c

wget (command line browser) source code

/* Various functions of utilitarian nature.
   Copyright (C) 1995, 1996, 1997, 1998, 2000, 2001
   Free Software Foundation, Inc.

This file is part of GNU Wget.

GNU Wget is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

GNU Wget is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Wget; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

In addition, as a special exception, the Free Software Foundation
gives permission to link the code of its release of Wget with the
OpenSSL project's "OpenSSL" library (or with modified versions of it
that use the same license as the "OpenSSL" library), and distribute
the linked executables.  You must obey the GNU General Public License
in all respects for all of the code used other than "OpenSSL".  If you
modify this file, you may extend this exception to your version of the
file, but you are not obligated to do so.  If you do not wish to do
so, delete this exception statement from your version.  */

#include <config.h>

#include <stdio.h>
#include <stdlib.h>
#ifdef HAVE_STRING_H
# include <string.h>
#else  /* not HAVE_STRING_H */
# include <strings.h>
#endif /* not HAVE_STRING_H */
#include <sys/types.h>
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#ifdef HAVE_MMAP
# include <sys/mman.h>
#endif
#ifdef HAVE_PWD_H
# include <pwd.h>
#endif
#include <limits.h>
#ifdef HAVE_UTIME_H
# include <utime.h>
#endif
#ifdef HAVE_SYS_UTIME_H
# include <sys/utime.h>
#endif
#include <errno.h>
#ifdef NeXT
# include <libc.h>		/* for access() */
#endif
#include <fcntl.h>
#include <assert.h>

/* For TIOCGWINSZ and friends: */
#ifdef HAVE_SYS_IOCTL_H
# include <sys/ioctl.h>
#endif
#ifdef HAVE_TERMIOS_H
# include <termios.h>
#endif

/* Needed for run_with_timeout. */
#undef USE_SIGNAL_TIMEOUT
#ifdef HAVE_SIGNAL_H
# include <signal.h>
#endif
#ifdef HAVE_SETJMP_H
# include <setjmp.h>
#endif

#ifndef HAVE_SIGSETJMP
/* If sigsetjmp is a macro, configure won't pick it up. */
# ifdef sigsetjmp
#  define HAVE_SIGSETJMP
# endif
#endif

#ifdef HAVE_SIGNAL
# ifdef HAVE_SIGSETJMP
#  define USE_SIGNAL_TIMEOUT
# endif
# ifdef HAVE_SIGBLOCK
#  define USE_SIGNAL_TIMEOUT
# endif
#endif

#include "wget.h"
#include "utils.h"
#include "hash.h"

#ifndef errno
extern int errno;
#endif

/* This section implements several wrappers around the basic
   allocation routines.  This is done for two reasons: first, so that
   the callers of these functions need not consistently check for
   errors.  If there is not enough virtual memory for running Wget,
   something is seriously wrong, and Wget exits with an appropriate
   error message.

   The second reason why these are useful is that, if DEBUG_MALLOC is
   defined, they also provide a handy (if crude) malloc debugging
   interface that checks memory leaks.  */

/* Croak the fatal memory error and bail out with non-zero exit
   status.  */
static void
memfatal (const char *what)
{
  /* Make sure we don't try to store part of the log line, and thus
     call malloc.  */
  log_set_save_context (0);
  logprintf (LOG_ALWAYS, _("%s: %s: Not enough memory.\n"), exec_name, what);
  exit (1);
}

/* These functions end with _real because they need to be
   distinguished from the debugging functions, and from the macros.
   Explanation follows:

   If memory debugging is not turned on, wget.h defines these:

     #define xmalloc xmalloc_real
     #define xrealloc xrealloc_real
     #define xstrdup xstrdup_real
     #define xfree free

   In case of memory debugging, the definitions are a bit more
   complex, because we want to provide more information, *and* we want
   to call the debugging code.  (The former is the reason why xmalloc
   and friends need to be macros in the first place.)  Then it looks
   like this:

     #define xmalloc(a) xmalloc_debug (a, __FILE__, __LINE__)
     #define xfree(a)   xfree_debug (a, __FILE__, __LINE__)
     #define xrealloc(a, b) xrealloc_debug (a, b, __FILE__, __LINE__)
     #define xstrdup(a) xstrdup_debug (a, __FILE__, __LINE__)

   Each of the *_debug function does its magic and calls the real one.  */

#ifdef DEBUG_MALLOC
# define STATIC_IF_DEBUG static
#else
# define STATIC_IF_DEBUG
#endif

STATIC_IF_DEBUG void *
xmalloc_real (size_t size)
{
  void *ptr = malloc (size);
  if (!ptr)
    memfatal ("malloc");
  return ptr;
}

STATIC_IF_DEBUG void *
xrealloc_real (void *ptr, size_t newsize)
{
  void *newptr;

  /* Not all Un*xes have the feature of realloc() that calling it with
     a NULL-pointer is the same as malloc(), but it is easy to
     simulate.  */
  if (ptr)
    newptr = realloc (ptr, newsize);
  else
    newptr = malloc (newsize);
  if (!newptr)
    memfatal ("realloc");
  return newptr;
}

STATIC_IF_DEBUG char *
xstrdup_real (const char *s)
{
  char *copy;

#ifndef HAVE_STRDUP
  int l = strlen (s);
  copy = malloc (l + 1);
  if (!copy)
    memfatal ("strdup");
  memcpy (copy, s, l + 1);
#else  /* HAVE_STRDUP */
  copy = strdup (s);
  if (!copy)
    memfatal ("strdup");
#endif /* HAVE_STRDUP */

  return copy;
}

#ifdef DEBUG_MALLOC

/* Crude home-grown routines for debugging some malloc-related
   problems.  Featured:

   * Counting the number of malloc and free invocations, and reporting
     the "balance", i.e. how many times more malloc was called than it
     was the case with free.

   * Making malloc store its entry into a simple array and free remove
     stuff from that array.  At the end, print the pointers which have
     not been freed, along with the source file and the line number.
     This also has the side-effect of detecting freeing memory that
     was never allocated.

   Note that this kind of memory leak checking strongly depends on
   every malloc() being followed by a free(), even if the program is
   about to finish.  Wget is careful to free the data structure it
   allocated in init.c.  */

static int malloc_count, free_count;

static struct {
  char *ptr;
  const char *file;
  int line;
} malloc_debug[100000];

/* Both register_ptr and unregister_ptr take O(n) operations to run,
   which can be a real problem.  It would be nice to use a hash table
   for malloc_debug, but the functions in hash.c are not suitable
   because they can call malloc() themselves.  Maybe it would work if
   the hash table were preallocated to a huge size, and if we set the
   rehash threshold to 1.0.  */

/* Register PTR in malloc_debug.  Abort if this is not possible
   (presumably due to the number of current allocations exceeding the
   size of malloc_debug.)  */

static void
register_ptr (void *ptr, const char *file, int line)
{
  int i;
  for (i = 0; i < countof (malloc_debug); i++)
    if (malloc_debug[i].ptr == NULL)
      {
	malloc_debug[i].ptr = ptr;
	malloc_debug[i].file = file;
	malloc_debug[i].line = line;
	return;
      }
  abort ();
}

/* Unregister PTR from malloc_debug.  Abort if PTR is not present in
   malloc_debug.  (This catches calling free() with a bogus pointer.)  */

static void
unregister_ptr (void *ptr)
{
  int i;
  for (i = 0; i < countof (malloc_debug); i++)
    if (malloc_debug[i].ptr == ptr)
      {
	malloc_debug[i].ptr = NULL;
	return;
      }
  abort ();
}

/* Print the malloc debug stats that can be gathered from the above
   information.  Currently this is the count of mallocs, frees, the
   difference between the two, and the dump of the contents of
   malloc_debug.  The last part are the memory leaks.  */

void
print_malloc_debug_stats (void)
{
  int i;
  printf ("\nMalloc:  %d\nFree:    %d\nBalance: %d\n\n",
	  malloc_count, free_count, malloc_count - free_count);
  for (i = 0; i < countof (malloc_debug); i++)
    if (malloc_debug[i].ptr != NULL)
      printf ("0x%08ld: %s:%d\n", (long)malloc_debug[i].ptr,
	      malloc_debug[i].file, malloc_debug[i].line);
}

void *
xmalloc_debug (size_t size, const char *source_file, int source_line)
{
  void *ptr = xmalloc_real (size);
  ++malloc_count;
  register_ptr (ptr, source_file, source_line);
  return ptr;
}

void
xfree_debug (void *ptr, const char *source_file, int source_line)
{
  assert (ptr != NULL);
  ++free_count;
  unregister_ptr (ptr);
  free (ptr);
}

void *
xrealloc_debug (void *ptr, size_t newsize, const char *source_file, int source_line)
{
  void *newptr = xrealloc_real (ptr, newsize);
  if (!ptr)
    {
      ++malloc_count;
      register_ptr (newptr, source_file, source_line);
    }
  else if (newptr != ptr)
    {
      unregister_ptr (ptr);
      register_ptr (newptr, source_file, source_line);
    }
  return newptr;
}

char *
xstrdup_debug (const char *s, const char *source_file, int source_line)
{
  char *copy = xstrdup_real (s);
  ++malloc_count;
  register_ptr (copy, source_file, source_line);
  return copy;
}

#endif /* DEBUG_MALLOC */

/* Utility function: like xstrdup(), but also lowercases S.  */

char *
xstrdup_lower (const char *s)
{
  char *copy = xstrdup (s);
  char *p = copy;
  for (; *p; p++)
    *p = TOLOWER (*p);
  return copy;
}

/* Return a count of how many times CHR occurs in STRING. */

int
count_char (const char *string, char chr)
{
  const char *p;
  int count = 0;
  for (p = string; *p; p++)
    if (*p == chr)
      ++count;
  return count;
}

/* Copy the string formed by two pointers (one on the beginning, other
   on the char after the last char) to a new, malloc-ed location.
   0-terminate it.  */
char *
strdupdelim (const char *beg, const char *end)
{
  char *res = (char *)xmalloc (end - beg + 1);
  memcpy (res, beg, end - beg);
  res[end - beg] = '\0';
  return res;
}

/* Parse a string containing comma-separated elements, and return a
   vector of char pointers with the elements.  Spaces following the
   commas are ignored.  */
char **
sepstring (const char *s)
{
  char **res;
  const char *p;
  int i = 0;

  if (!s || !*s)
    return NULL;
  res = NULL;
  p = s;
  while (*s)
    {
      if (*s == ',')
	{
	  res = (char **)xrealloc (res, (i + 2) * sizeof (char *));
	  res[i] = strdupdelim (p, s);
	  res[++i] = NULL;
	  ++s;
	  /* Skip the blanks following the ','.  */
	  while (ISSPACE (*s))
	    ++s;
	  p = s;
	}
      else
	++s;
    }
  res = (char **)xrealloc (res, (i + 2) * sizeof (char *));
  res[i] = strdupdelim (p, s);
  res[i + 1] = NULL;
  return res;
}

/* Return pointer to a static char[] buffer in which zero-terminated
   string-representation of TM (in form hh:mm:ss) is printed.

   If TM is non-NULL, the current time-in-seconds will be stored
   there.

   (#### This is misleading: one would expect TM would be used instead
   of the current time in that case.  This design was probably
   influenced by the design time(2), and should be changed at some
   points.  No callers use non-NULL TM anyway.)  */

char *
time_str (time_t *tm)
{
  static char output[15];
  struct tm *ptm;
  time_t secs = time (tm);

  if (secs == -1)
    {
      /* In case of error, return the empty string.  Maybe we should
	 just abort if this happens?  */
      *output = '\0';
      return output;
    }
  ptm = localtime (&secs);
  sprintf (output, "%02d:%02d:%02d", ptm->tm_hour, ptm->tm_min, ptm->tm_sec);
  return output;
}

/* Like the above, but include the date: YYYY-MM-DD hh:mm:ss.  */

char *
datetime_str (time_t *tm)
{
  static char output[20];	/* "YYYY-MM-DD hh:mm:ss" + \0 */
  struct tm *ptm;
  time_t secs = time (tm);

  if (secs == -1)
    {
      /* In case of error, return the empty string.  Maybe we should
	 just abort if this happens?  */
      *output = '\0';
      return output;
    }
  ptm = localtime (&secs);
  sprintf (output, "%04d-%02d-%02d %02d:%02d:%02d",
	   ptm->tm_year + 1900, ptm->tm_mon + 1, ptm->tm_mday,
	   ptm->tm_hour, ptm->tm_min, ptm->tm_sec);
  return output;
}

/* The Windows versions of the following two functions are defined in
   mswindows.c.  */

#ifndef WINDOWS
void
fork_to_background (void)
{
  pid_t pid;
  /* Whether we arrange our own version of opt.lfilename here.  */
  int changedp = 0;

  if (!opt.lfilename)
    {
      opt.lfilename = unique_name (DEFAULT_LOGFILE, 0);
      changedp = 1;
    }
  pid = fork ();
  if (pid < 0)
    {
      /* parent, error */
      perror ("fork");
      exit (1);
    }
  else if (pid != 0)
    {
      /* parent, no error */
      printf (_("Continuing in background, pid %d.\n"), (int)pid);
      if (changedp)
	printf (_("Output will be written to `%s'.\n"), opt.lfilename);
      exit (0);			/* #### should we use _exit()? */
    }

  /* child: give up the privileges and keep running. */
  setsid ();
  freopen ("/dev/null", "r", stdin);
  freopen ("/dev/null", "w", stdout);
  freopen ("/dev/null", "w", stderr);
}
#endif /* not WINDOWS */

/* "Touch" FILE, i.e. make its atime and mtime equal to the time
   specified with TM.  */
void
touch (const char *file, time_t tm)
{
#ifdef HAVE_STRUCT_UTIMBUF
  struct utimbuf times;
  times.actime = times.modtime = tm;
#else
  time_t times[2];
  times[0] = times[1] = tm;
#endif

  if (utime (file, &times) == -1)
    logprintf (LOG_NOTQUIET, "utime(%s): %s\n", file, strerror (errno));
}

/* Checks if FILE is a symbolic link, and removes it if it is.  Does
   nothing under MS-Windows.  */
int