src/yes.c

   1 /* yes - output a string repeatedly until killed
   2    Copyright (C) 1991-2015 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 /* David MacKenzie <djm@gnu.ai.mit.edu> */
  18
  19 #include <config.h>
  20 #include <stdio.h>
  21 #include <sys/types.h>
  22 #include <getopt.h>
  23
  24 #include "system.h"
  25
  26 #include "error.h"
  27 #include "long-options.h"
  28
  29 /* The official name of this program (e.g., no 'g' prefix).  */
  30 #define PROGRAM_NAME "yes"
  31
  32 #define AUTHORS proper_name ("David MacKenzie")
  33
  34 void
  35 usage (int status)
  36 {
  37   if (status != EXIT_SUCCESS)
  38     emit_try_help ();
  39   else
  40     {
  41       printf (_("\
  42 Usage: %s [STRING]...\n\
  43   or:  %s OPTION\n\
  44 "),
  45               program_name, program_name);
  46
  47       fputs (_("\
  48 Repeatedly output a line with all specified STRING(s), or 'y'.\n\
  49 \n\
  50 "), stdout);
  51       fputs (HELP_OPTION_DESCRIPTION, stdout);
  52       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  53       emit_ancillary_info (PROGRAM_NAME);
  54     }
  55   exit (status);
  56 }
  57
  58 int
  59 main (int argc, char **argv)
  60 {
  61   char buf[BUFSIZ];
  62   char *pbuf = buf;
  63   int i;
  64
  65   initialize_main (&argc, &argv);
  66   set_program_name (argv[0]);
  67   setlocale (LC_ALL, "");
  68   bindtextdomain (PACKAGE, LOCALEDIR);
  69   textdomain (PACKAGE);
  70
  71   atexit (close_stdout);
  72
  73   parse_long_options (argc, argv, PROGRAM_NAME, PACKAGE_NAME, Version,
  74                       usage, AUTHORS, (char const *) NULL);
  75   if (getopt_long (argc, argv, "+", NULL, NULL) != -1)
  76     usage (EXIT_FAILURE);
  77
  78   if (argc <= optind)
  79     {
  80       optind = argc;
  81       argv[argc++] = bad_cast ("y");
  82     }
  83
  84   /* Buffer data locally once, rather than having the
  85      large overhead of stdio buffering each item.  */
  86   for (i = optind; i < argc; i++)
  87     {
  88       size_t len = strlen (argv[i]);
  89       if (BUFSIZ < len || BUFSIZ - len <= pbuf - buf)
  90         break;
  91       memcpy (pbuf, argv[i], len);
  92       pbuf += len;
  93       *pbuf++ = i == argc - 1 ? '\n' : ' ';
  94     }
  95   if (i == argc)
  96     {
  97       size_t line_len = pbuf - buf;
  98       size_t lines = BUFSIZ / line_len;
  99       while (--lines)
 100         {
 101           memcpy (pbuf, pbuf - line_len, line_len);
 102           pbuf += line_len;
 103         }
 104     }
 105
 106   /* The normal case is to continuously output the local buffer.  */
 107   while (i == argc)
 108     {
 109       if (write (STDOUT_FILENO, buf, pbuf - buf) == -1)
 110         {
 111           error (0, errno, _("standard output"));
 112           return EXIT_FAILURE;
 113         }
 114     }
 115
 116   /* If the data doesn't fit in BUFSIZ then output
 117      what we've buffered, and iterate over the remaining items.  */
 118   while (true /* i != argc */)
 119     {
 120       int j;
 121       if ((pbuf - buf) && fwrite (buf, pbuf - buf, 1, stdout) != 1)
 122         {
 123           error (0, errno, _("standard output"));
 124           return EXIT_FAILURE;
 125         }
 126       for (j = i; j < argc; j++)
 127         if (fputs (argv[j], stdout) == EOF
 128             || putchar (j == argc - 1 ? '\n' : ' ') == EOF)
 129           {
 130             error (0, errno, _("standard output"));
 131             return EXIT_FAILURE;
 132           }
 133     }
 134 }