coreutils/src/tee.c

/* tee - read from standard input and write to standard output and files.
   Copyright (C) 85,1990-2005 Free Software Foundation, Inc.

   This program 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, or (at your option)
   any later version.

   This program 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 this program; if not, write to the Free Software Foundation,
   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */

/* Mike Parker, Richard M. Stallman, and David MacKenzie */

#include <config.h>
#include <stdio.h>
#include <sys/types.h>
#include <signal.h>
#include <getopt.h>

#include "system.h"
#include "error.h"
#include "stdio-safer.h"

/* The official name of this program (e.g., no `g' prefix).  */
#define PROGRAM_NAME "tee"

#define AUTHORS "Mike Parker", "Richard M. Stallman", "David MacKenzie"

static bool tee (int nfiles, const char **files);

/* If true, append to output files rather than truncating them. */
static bool append;

/* If true, ignore interrupts. */
static bool ignore_interrupts;

/* The name that this program was run with. */
char *program_name;

static struct option const long_options[] =
{
  {"append", no_argument, NULL, 'a'},
  {"ignore-interrupts", no_argument, NULL, 'i'},
  {GETOPT_HELP_OPTION_DECL},
  {GETOPT_VERSION_OPTION_DECL},
  {NULL, 0, NULL, 0}
};

void
usage (int status)
{
  if (status != EXIT_SUCCESS)
    fprintf (stderr, _("Try `%s --help' for more information.\n"),
	     program_name);
  else
    {
      printf (_("Usage: %s [OPTION]... [FILE]...\n"), program_name);
      fputs (_("\
Copy standard input to each FILE, and also to standard output.\n\
\n\
  -a, --append              append to the given FILEs, do not overwrite\n\
  -i, --ignore-interrupts   ignore interrupt signals\n\
"), stdout);
      fputs (HELP_OPTION_DESCRIPTION, stdout);
      fputs (VERSION_OPTION_DESCRIPTION, stdout);
      fputs (_("\
\n\
If a FILE is -, copy again to standard output.\n\
"), stdout);
      printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
    }
  exit (status);
}

int
main (int argc, char **argv)
{
  bool ok;
  int optc;

  initialize_main (&argc, &argv);
  program_name = argv[0];
  setlocale (LC_ALL, "");
  bindtextdomain (PACKAGE, LOCALEDIR);
  textdomain (PACKAGE);

  atexit (close_stdout);

  append = false;
  ignore_interrupts = false;

  while ((optc = getopt_long (argc, argv, "ai", long_options, NULL)) != -1)
    {
      switch (optc)
	{
	case 'a':
	  append = true;
	  break;

	case 'i':
	  ignore_interrupts = true;
	  break;

	case_GETOPT_HELP_CHAR;

	case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);

	default:
	  usage (EXIT_FAILURE);
	}
    }

  if (ignore_interrupts)
    signal (SIGINT, SIG_IGN);

  /* Do *not* warn if tee is given no file arguments.
     POSIX requires that it work when given no arguments.  */

  ok = tee (argc - optind, (const char **) &argv[optind]);
  if (close (STDIN_FILENO) != 0)
    error (EXIT_FAILURE, errno, _("standard input"));

  exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
}

/* Copy the standard input into each of the NFILES files in FILES
   and into the standard output.
   Return true if successful.  */

static bool
tee (int nfiles, const char **files)
{
  FILE **descriptors;
  char buffer[BUFSIZ];
  ssize_t bytes_read;
  int i;
  bool ok = true;
  const char *mode_string = (append ? "a" : "w");

  descriptors = xnmalloc (nfiles + 1, sizeof *descriptors);

  /* Move all the names `up' one in the argv array to make room for
     the entry for standard output.  This writes into argv[argc].  */
  for (i = nfiles; i >= 1; i--)
    files[i] = files[i - 1];

  SET_BINARY2 (0, 1);

  /* In the array of NFILES + 1 descriptors, make
     the first one correspond to standard output.   */
  descriptors[0] = stdout;
  files[0] = _("standard output");
  SETVBUF (stdout, NULL, _IONBF, 0);

  for (i = 1; i <= nfiles; i++)
    {
      descriptors[i] = (STREQ (files[i], "-")
			? stdout
			: fopen_safer (files[i], mode_string));
      if (descriptors[i] == NULL)
	{
	  error (0, errno, "%s", files[i]);
	  ok = false;
	}
      else
	{
	  SETVBUF (descriptors[i], NULL, _IONBF, 0);
	  SET_BINARY (fileno (descriptors[i]));
	}
    }

  while (1)
    {
      bytes_read = read (0, buffer, sizeof buffer);
#ifdef EINTR
      if (bytes_read < 0 && errno == EINTR)
        continue;
#endif
      if (bytes_read <= 0)
	break;

      /* Write to all NFILES + 1 descriptors.
	 Standard output is the first one.  */
      for (i = 0; i <= nfiles; i++)
	if (descriptors[i]
	    && fwrite (buffer, 1, bytes_read, descriptors[i]) != bytes_read)
	  {
	    error (0, errno, "%s", files[i]);
	    descriptors[i] = NULL;
	    ok = false;
	  }
    }

  if (bytes_read == -1)
    {
      error (0, errno, _("read error"));
      ok = false;
    }

  /* Close the files, but not standard output.  */
  for (i = 1; i <= nfiles; i++)
    if (!STREQ (files[i], "-")
	&& descriptors[i] && fclose (descriptors[i]) != 0)
      {
	error (0, errno, "%s", files[i]);
	ok = false;
      }

  free (descriptors);

  return ok;
}