src/tee.c

   1 /* tee - read from standard input and write to standard output and files.
   2    Copyright (C) 1985-2012 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  16
  17 /* Mike Parker, Richard M. Stallman, and David MacKenzie */
  18
  19 #include <config.h>
  20 #include <sys/types.h>
  21 #include <signal.h>
  22 #include <getopt.h>
  23
  24 #include "system.h"
  25 #include "error.h"
  26 #include "fadvise.h"
  27 #include "stdio--.h"
  28 #include "xfreopen.h"
  29
  30 /* The official name of this program (e.g., no 'g' prefix).  */
  31 #define PROGRAM_NAME "tee"
  32
  33 #define AUTHORS \
  34   proper_name ("Mike Parker"), \
  35   proper_name ("Richard M. Stallman"), \
  36   proper_name ("David MacKenzie")
  37
  38 static bool tee_files (int nfiles, const char **files);
  39
  40 /* If true, append to output files rather than truncating them. */
  41 static bool append;
  42
  43 /* If true, ignore interrupts. */
  44 static bool ignore_interrupts;
  45
  46 static struct option const long_options[] =
  47 {
  48   {"append", no_argument, NULL, 'a'},
  49   {"ignore-interrupts", no_argument, NULL, 'i'},
  50   {GETOPT_HELP_OPTION_DECL},
  51   {GETOPT_VERSION_OPTION_DECL},
  52   {NULL, 0, NULL, 0}
  53 };
  54
  55 void
  56 usage (int status)
  57 {
  58   if (status != EXIT_SUCCESS)
  59     emit_try_help ();
  60   else
  61     {
  62       printf (_("Usage: %s [OPTION]... [FILE]...\n"), program_name);
  63       fputs (_("\
  64 Copy standard input to each FILE, and also to standard output.\n\
  65 \n\
  66   -a, --append              append to the given FILEs, do not overwrite\n\
  67   -i, --ignore-interrupts   ignore interrupt signals\n\
  68 "), stdout);
  69       fputs (HELP_OPTION_DESCRIPTION, stdout);
  70       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  71       fputs (_("\
  72 \n\
  73 If a FILE is -, copy again to standard output.\n\
  74 "), stdout);
  75       emit_ancillary_info ();
  76     }
  77   exit (status);
  78 }
  79
  80 int
  81 main (int argc, char **argv)
  82 {
  83   bool ok;
  84   int optc;
  85
  86   initialize_main (&argc, &argv);
  87   set_program_name (argv[0]);
  88   setlocale (LC_ALL, "");
  89   bindtextdomain (PACKAGE, LOCALEDIR);
  90   textdomain (PACKAGE);
  91
  92   atexit (close_stdout);
  93
  94   append = false;
  95   ignore_interrupts = false;
  96
  97   while ((optc = getopt_long (argc, argv, "ai", long_options, NULL)) != -1)
  98     {
  99       switch (optc)
 100         {
 101         case 'a':
 102           append = true;
 103           break;
 104
 105         case 'i':
 106           ignore_interrupts = true;
 107           break;
 108
 109         case_GETOPT_HELP_CHAR;
 110
 111         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 112
 113         default:
 114           usage (EXIT_FAILURE);
 115         }
 116     }
 117
 118   if (ignore_interrupts)
 119     signal (SIGINT, SIG_IGN);
 120
 121   /* Do *not* warn if tee is given no file arguments.
 122      POSIX requires that it work when given no arguments.  */
 123
 124   ok = tee_files (argc - optind, (const char **) &argv[optind]);
 125   if (close (STDIN_FILENO) != 0)
 126     error (EXIT_FAILURE, errno, _("standard input"));
 127
 128   exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
 129 }
 130
 131 /* Copy the standard input into each of the NFILES files in FILES
 132    and into the standard output.
 133    Return true if successful.  */
 134
 135 static bool
 136 tee_files (int nfiles, const char **files)
 137 {
 138   FILE **descriptors;
 139   char buffer[BUFSIZ];
 140   ssize_t bytes_read;
 141   int i;
 142   bool ok = true;
 143   char const *mode_string =
 144     (O_BINARY
 145      ? (append ? "ab" : "wb")
 146      : (append ? "a" : "w"));
 147
 148   descriptors = xnmalloc (nfiles + 1, sizeof *descriptors);
 149
 150   /* Move all the names 'up' one in the argv array to make room for
 151      the entry for standard output.  This writes into argv[argc].  */
 152   for (i = nfiles; i >= 1; i--)
 153     files[i] = files[i - 1];
 154
 155   if (O_BINARY && ! isatty (STDIN_FILENO))
 156     xfreopen (NULL, "rb", stdin);
 157   if (O_BINARY && ! isatty (STDOUT_FILENO))
 158     xfreopen (NULL, "wb", stdout);
 159
 160   fadvise (stdin, FADVISE_SEQUENTIAL);
 161
 162   /* In the array of NFILES + 1 descriptors, make
 163      the first one correspond to standard output.   */
 164   descriptors[0] = stdout;
 165   files[0] = _("standard output");
 166   setvbuf (stdout, NULL, _IONBF, 0);
 167
 168   for (i = 1; i <= nfiles; i++)
 169     {
 170       descriptors[i] = (STREQ (files[i], "-")
 171                         ? stdout
 172                         : fopen (files[i], mode_string));
 173       if (descriptors[i] == NULL)
 174         {
 175           error (0, errno, "%s", files[i]);
 176           ok = false;
 177         }
 178       else
 179         setvbuf (descriptors[i], NULL, _IONBF, 0);
 180     }
 181
 182   while (1)
 183     {
 184       bytes_read = read (0, buffer, sizeof buffer);
 185       if (bytes_read < 0 && errno == EINTR)
 186         continue;
 187       if (bytes_read <= 0)
 188         break;
 189
 190       /* Write to all NFILES + 1 descriptors.
 191          Standard output is the first one.  */
 192       for (i = 0; i <= nfiles; i++)
 193         if (descriptors[i]
 194             && fwrite (buffer, bytes_read, 1, descriptors[i]) != 1)
 195           {
 196             error (0, errno, "%s", files[i]);
 197             descriptors[i] = NULL;
 198             ok = false;
 199           }
 200     }
 201
 202   if (bytes_read == -1)
 203     {
 204       error (0, errno, _("read error"));
 205       ok = false;
 206     }
 207
 208   /* Close the files, but not standard output.  */
 209   for (i = 1; i <= nfiles; i++)
 210     if (!STREQ (files[i], "-")
 211         && descriptors[i] && fclose (descriptors[i]) != 0)
 212       {
 213         error (0, errno, "%s", files[i]);
 214         ok = false;
 215       }
 216
 217   free (descriptors);
 218
 219   return ok;
 220 }