examples/loadables/cat.c

   1 /*
   2  * cat replacement
   3  *
   4  * no options - the way cat was intended
   5  */
   6
   7 /*
   8    Copyright (C) 1999-2009 Free Software Foundation, Inc.
   9
  10    This file is part of GNU Bash.
  11    Bash is free software: you can redistribute it and/or modify
  12    it under the terms of the GNU General Public License as published by
  13    the Free Software Foundation, either version 3 of the License, or
  14    (at your option) any later version.
  15
  16    Bash is distributed in the hope that it will be useful,
  17    but WITHOUT ANY WARRANTY; without even the implied warranty of
  18    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19    GNU General Public License for more details.
  20
  21    You should have received a copy of the GNU General Public License
  22    along with Bash.  If not, see <http://www.gnu.org/licenses/>.
  23 */
  24
  25 #include <fcntl.h>
  26 #include <errno.h>
  27
  28 #include "builtins.h"
  29 #include "shell.h"
  30
  31 #ifndef errno
  32 extern int errno;
  33 #endif
  34
  35 extern char *strerror ();
  36 extern char **make_builtin_argv ();
  37
  38 static int
  39 fcopy(fd)
  40 int     fd;
  41 {
  42         char    buf[1024], *s;
  43         int     n, w, e;
  44
  45         while (n = read(fd, buf, sizeof (buf))) {
  46                 w = write(1, buf, n);
  47                 if (w != n) {
  48                         e = errno;
  49                         write(2, "cat: write error: ", 18);
  50                         s = strerror(e);
  51                         write(2, s, strlen(s));
  52                         write(2, "\n", 1);
  53                         return 1;
  54                 }
  55         }
  56         return 0;
  57 }
  58
  59 cat_main (argc, argv)
  60 int     argc;
  61 char    **argv;
  62 {
  63         int     i, fd, r;
  64         char    *s;
  65
  66         if (argc == 1)
  67                 return (fcopy(0));
  68
  69         for (i = r = 1; i < argc; i++) {
  70                 if (argv[i][0] == '-' && argv[i][1] == '\0')
  71                         fd = 0;
  72                 else {
  73                         fd = open(argv[i], O_RDONLY, 0666);
  74                         if (fd < 0) {
  75                                 s = strerror(errno);
  76                                 write(2, "cat: cannot open ", 17);
  77                                 write(2, argv[i], strlen(argv[i]));
  78                                 write(2, ": ", 2);
  79                                 write(2, s, strlen(s));
  80                                 write(2, "\n", 1);
  81                                 continue;
  82                         }
  83                 }
  84                 r = fcopy(fd);
  85                 if (fd != 0)
  86                         close(fd);
  87         }
  88         return (r);
  89 }
  90
  91 cat_builtin(list)
  92 WORD_LIST *list;
  93 {
  94         char    **v;
  95         int     c, r;
  96
  97         v = make_builtin_argv(list, &c);
  98         r = cat_main(c, v);
  99         free(v);
 100
 101         return r;
 102 }
 103
 104 char *cat_doc[] = {
 105         "Display files.",
 106         "",
 107         "Read each FILE and display it on the standard output.   If any",
 108         "FILE is `-' or if no FILE argument is given, the standard input",
 109         "is read.",
 110         (char *)0
 111 };
 112
 113 struct builtin cat_struct = {
 114         "cat",
 115         cat_builtin,
 116         BUILTIN_ENABLED,
 117         cat_doc,
 118         "cat [-] [file ...]",
 119         0
 120 };