src/tee.c

   1 /* tee - read from standard input and write to standard output and files.
   2    Copyright (C) 1985-2019 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 <https://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 "argmatch.h"
  26 #include "die.h"
  27 #include "error.h"
  28 #include "fadvise.h"
  29 #include "stdio--.h"
  30 #include "xbinary-io.h"
  31
  32 /* The official name of this program (e.g., no 'g' prefix).  */
  33 #define PROGRAM_NAME "tee"
  34
  35 #define AUTHORS \
  36   proper_name ("Mike Parker"), \
  37   proper_name ("Richard M. Stallman"), \
  38   proper_name ("David MacKenzie")
  39
  40 static bool tee_files (int nfiles, char **files);
  41
  42 /* If true, append to output files rather than truncating them. */
  43 static bool append;
  44
  45 /* If true, ignore interrupts. */
  46 static bool ignore_interrupts;
  47
  48 enum output_error
  49   {
  50     output_error_sigpipe,      /* traditional behavior, sigpipe enabled.  */
  51     output_error_warn,         /* warn on EPIPE, but continue.  */
  52     output_error_warn_nopipe,  /* ignore EPIPE, continue.  */
  53     output_error_exit,         /* exit on any output error.  */
  54     output_error_exit_nopipe   /* exit on any output error except EPIPE.  */
  55   };
  56
  57 static enum output_error output_error;
  58
  59 static struct option const long_options[] =
  60 {
  61   {"append", no_argument, NULL, 'a'},
  62   {"ignore-interrupts", no_argument, NULL, 'i'},
  63   {"output-error", optional_argument, NULL, 'p'},
  64   {GETOPT_HELP_OPTION_DECL},
  65   {GETOPT_VERSION_OPTION_DECL},
  66   {NULL, 0, NULL, 0}
  67 };
  68
  69 static char const *const output_error_args[] =
  70 {
  71   "warn", "warn-nopipe", "exit", "exit-nopipe", NULL
  72 };
  73 static enum output_error const output_error_types[] =
  74 {
  75   output_error_warn, output_error_warn_nopipe,
  76   output_error_exit, output_error_exit_nopipe
  77 };
  78 ARGMATCH_VERIFY (output_error_args, output_error_types);
  79
  80 void
  81 usage (int status)
  82 {
  83   if (status != EXIT_SUCCESS)
  84     emit_try_help ();
  85   else
  86     {
  87       printf (_("Usage: %s [OPTION]... [FILE]...\n"), program_name);
  88       fputs (_("\
  89 Copy standard input to each FILE, and also to standard output.\n\
  90 \n\
  91   -a, --append              append to the given FILEs, do not overwrite\n\
  92   -i, --ignore-interrupts   ignore interrupt signals\n\
  93 "), stdout);
  94       fputs (_("\
  95   -p                        diagnose errors writing to non pipes\n\
  96       --output-error[=MODE]   set behavior on write error.  See MODE below\n\
  97 "), stdout);
  98       fputs (HELP_OPTION_DESCRIPTION, stdout);
  99       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 100       fputs (_("\
 101 \n\
 102 MODE determines behavior with write errors on the outputs:\n\
 103   'warn'         diagnose errors writing to any output\n\
 104   'warn-nopipe'  diagnose errors writing to any output not a pipe\n\
 105   'exit'         exit on error writing to any output\n\
 106   'exit-nopipe'  exit on error writing to any output not a pipe\n\
 107 The default MODE for the -p option is 'warn-nopipe'.\n\
 108 The default operation when --output-error is not specified, is to\n\
 109 exit immediately on error writing to a pipe, and diagnose errors\n\
 110 writing to non pipe outputs.\n\
 111 "), stdout);
 112       emit_ancillary_info (PROGRAM_NAME);
 113     }
 114   exit (status);
 115 }
 116
 117 int
 118 main (int argc, char **argv)
 119 {
 120   bool ok;
 121   int optc;
 122
 123   initialize_main (&argc, &argv);
 124   set_program_name (argv[0]);
 125   setlocale (LC_ALL, "");
 126   bindtextdomain (PACKAGE, LOCALEDIR);
 127   textdomain (PACKAGE);
 128
 129   atexit (close_stdout);
 130
 131   append = false;
 132   ignore_interrupts = false;
 133
 134   while ((optc = getopt_long (argc, argv, "aip", long_options, NULL)) != -1)
 135     {
 136       switch (optc)
 137         {
 138         case 'a':
 139           append = true;
 140           break;
 141
 142         case 'i':
 143           ignore_interrupts = true;
 144           break;
 145
 146         case 'p':
 147           if (optarg)
 148             output_error = XARGMATCH ("--output-error", optarg,
 149                                       output_error_args, output_error_types);
 150           else
 151             output_error = output_error_warn_nopipe;
 152           break;
 153
 154         case_GETOPT_HELP_CHAR;
 155
 156         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 157
 158         default:
 159           usage (EXIT_FAILURE);
 160         }
 161     }
 162
 163   if (ignore_interrupts)
 164     signal (SIGINT, SIG_IGN);
 165
 166   if (output_error != output_error_sigpipe)
 167     signal (SIGPIPE, SIG_IGN);
 168
 169   /* Do *not* warn if tee is given no file arguments.
 170      POSIX requires that it work when given no arguments.  */
 171
 172   ok = tee_files (argc - optind, &argv[optind]);
 173   if (close (STDIN_FILENO) != 0)
 174     die (EXIT_FAILURE, errno, "%s", _("standard input"));
 175
 176   return ok ? EXIT_SUCCESS : EXIT_FAILURE;
 177 }
 178
 179 /* Copy the standard input into each of the NFILES files in FILES
 180    and into the standard output.  As a side effect, modify FILES[-1].
 181    Return true if successful.  */
 182
 183 static bool
 184 tee_files (int nfiles, char **files)
 185 {
 186   size_t n_outputs = 0;
 187   FILE **descriptors;
 188   char buffer[BUFSIZ];
 189   ssize_t bytes_read = 0;
 190   int i;
 191   bool ok = true;
 192   char const *mode_string =
 193     (O_BINARY
 194      ? (append ? "ab" : "wb")
 195      : (append ? "a" : "w"));
 196
 197   xset_binary_mode (STDIN_FILENO, O_BINARY);
 198   xset_binary_mode (STDOUT_FILENO, O_BINARY);
 199   fadvise (stdin, FADVISE_SEQUENTIAL);
 200
 201   /* Set up FILES[0 .. NFILES] and DESCRIPTORS[0 .. NFILES].
 202      In both arrays, entry 0 corresponds to standard output.  */
 203
 204   descriptors = xnmalloc (nfiles + 1, sizeof *descriptors);
 205   files--;
 206   descriptors[0] = stdout;
 207   files[0] = bad_cast (_("standard output"));
 208   setvbuf (stdout, NULL, _IONBF, 0);
 209   n_outputs++;
 210
 211   for (i = 1; i <= nfiles; i++)
 212     {
 213       /* Do not treat "-" specially - as mandated by POSIX.  */
 214       descriptors[i] = fopen (files[i], mode_string);
 215       if (descriptors[i] == NULL)
 216         {
 217           error (output_error == output_error_exit
 218                  || output_error == output_error_exit_nopipe,
 219                  errno, "%s", quotef (files[i]));
 220           ok = false;
 221         }
 222       else
 223         {
 224           setvbuf (descriptors[i], NULL, _IONBF, 0);
 225           n_outputs++;
 226         }
 227     }
 228
 229   while (n_outputs)
 230     {
 231       bytes_read = read (STDIN_FILENO, buffer, sizeof buffer);
 232       if (bytes_read < 0 && errno == EINTR)
 233         continue;
 234       if (bytes_read <= 0)
 235         break;
 236
 237       /* Write to all NFILES + 1 descriptors.
 238          Standard output is the first one.  */
 239       for (i = 0; i <= nfiles; i++)
 240         if (descriptors[i]
 241             && fwrite (buffer, bytes_read, 1, descriptors[i]) != 1)
 242           {
 243             int w_errno = errno;
 244             bool fail = errno != EPIPE || (output_error == output_error_exit
 245                                           || output_error == output_error_warn);
 246             if (descriptors[i] == stdout)
 247               clearerr (stdout); /* Avoid redundant close_stdout diagnostic.  */
 248             if (fail)
 249               {
 250                 error (output_error == output_error_exit
 251                        || output_error == output_error_exit_nopipe,
 252                        w_errno, "%s", quotef (files[i]));
 253               }
 254             descriptors[i] = NULL;
 255             if (fail)
 256               ok = false;
 257             n_outputs--;
 258           }
 259     }
 260
 261   if (bytes_read == -1)
 262     {
 263       error (0, errno, _("read error"));
 264       ok = false;
 265     }
 266
 267   /* Close the files, but not standard output.  */
 268   for (i = 1; i <= nfiles; i++)
 269     if (descriptors[i] && fclose (descriptors[i]) != 0)
 270       {
 271         error (0, errno, "%s", quotef (files[i]));
 272         ok = false;
 273       }
 274
 275   free (descriptors);
 276
 277   return ok;
 278 }