examples/loadables/tee.c

   1 /* tee - duplicate standard input */
   2
   3 /* See Makefile for compilation details. */
   4
   5 /*
   6    Copyright (C) 1999-2009 Free Software Foundation, Inc.
   7
   8    This file is part of GNU Bash.
   9    Bash is free software: you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation, either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    Bash is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with Bash.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 #include "config.h"
  24
  25 #include "bashtypes.h"
  26 #include "posixstat.h"
  27 #include "filecntl.h"
  28
  29 #include <signal.h>
  30
  31 #if defined (HAVE_UNISTD_H)
  32 #  include <unistd.h>
  33 #endif
  34
  35 #include "bashansi.h"
  36
  37 #include <stdio.h>
  38 #include <errno.h>
  39
  40 #include "builtins.h"
  41 #include "shell.h"
  42 #include "bashgetopt.h"
  43 #include "common.h"
  44
  45 #if !defined (errno)
  46 extern int errno;
  47 #endif
  48
  49 typedef struct flist {
  50   struct flist *next;
  51   int fd;
  52   char *fname;
  53 } FLIST;
  54
  55 static FLIST *tee_flist;
  56
  57 #define TEE_BUFSIZE     8192
  58
  59 extern int interrupt_immediately;
  60
  61 extern char *strerror ();
  62
  63 int
  64 tee_builtin (list)
  65      WORD_LIST *list;
  66 {
  67   int opt, append, nointr, rval, fd, fflags;
  68   int n, nr, nw;
  69   FLIST *fl;
  70   char *buf, *bp;
  71
  72   char *t;
  73
  74   reset_internal_getopt ();
  75   append = nointr = 0;
  76   tee_flist = (FLIST *)NULL;
  77   while ((opt = internal_getopt (list, "ai")) != -1)
  78     {
  79       switch (opt)
  80         {
  81         case 'a':
  82           append = 1;
  83           break;
  84         case 'i':
  85           nointr = 1;
  86           break;
  87         CASE_HELPOPT;
  88         default:
  89           builtin_usage ();
  90           return (EX_USAGE);
  91         }
  92     }
  93   list = loptend;
  94
  95   if (nointr == 0)
  96     interrupt_immediately++;
  97
  98   buf = xmalloc (TEE_BUFSIZE);
  99
 100   /* Initialize output file list. */
 101   fl = tee_flist = (FLIST *)xmalloc (sizeof(FLIST));
 102   tee_flist->fd = 1;
 103   tee_flist->fname = "stdout";
 104   tee_flist->next = (FLIST *)NULL;
 105
 106   /* Add file arguments to list of output files. */
 107   fflags = append ? O_WRONLY|O_CREAT|O_APPEND : O_WRONLY|O_CREAT|O_TRUNC;
 108   for (rval = EXECUTION_SUCCESS; list; list = list->next)
 109     {
 110       fd = open (list->word->word, fflags, 0666);
 111       if (fd < 0)
 112         {
 113           builtin_error ("%s: cannot open: %s", list->word->word, strerror (errno));
 114           rval = EXECUTION_FAILURE;
 115         }
 116       else
 117         {
 118           fl->next = (FLIST *)xmalloc (sizeof(FLIST));
 119           fl->next->fd = fd;
 120           fl->next->fname = list->word->word;
 121           fl = fl->next;
 122           fl->next = (FLIST *)NULL;
 123         }
 124     }
 125
 126   while ((nr = read(0, buf, TEE_BUFSIZE)) > 0)
 127     for (fl = tee_flist; fl; fl = fl->next)
 128       {
 129         n = nr;
 130         bp = buf;
 131         do
 132           {
 133             if ((nw = write (fl->fd, bp, n)) == -1)
 134               {
 135                 builtin_error ("%s: write error: %s", fl->fname, strerror (errno));
 136                 rval = EXECUTION_FAILURE;
 137                 break;
 138               }
 139             bp += nw;
 140           }
 141         while (n -= nw);
 142       }
 143   if (nr < 0)
 144     builtin_error ("read error: %s", strerror (errno));
 145
 146   /* Deallocate resources -- this is a builtin command. */
 147   tee_flist = tee_flist->next;          /* skip bogus close of stdout */
 148   while (tee_flist)
 149     {
 150       fl = tee_flist;
 151       if (close (fl->fd) < 0)
 152         {
 153           builtin_error ("%s: close_error: %s", fl->fname, strerror (errno));
 154           rval = EXECUTION_FAILURE;
 155         }
 156       tee_flist = tee_flist->next;
 157       free (fl);
 158     }
 159
 160   return (rval);
 161 }
 162
 163 char *tee_doc[] = {
 164         "Duplicate standard output.",
 165         "",
 166         "Copy standard input to standard output, making a copy in each",
 167         "filename argument.  If the `-a' option is given, the specified",
 168         "files are appended to, otherwise they are overwritten.  If the",
 169         "`-i' option is supplied, tee ignores interrupts.",
 170         (char *)NULL
 171 };
 172
 173 struct builtin tee_struct = {
 174         "tee",                  /* builtin name */
 175         tee_builtin,            /* function implementing the builtin */
 176         BUILTIN_ENABLED,        /* initial flags for builtin */
 177         tee_doc,                /* array of long documentation strings. */
 178         "tee [-ai] [file ...]", /* usage synopsis; becomes short_doc */
 179         0                       /* reserved for internal use */
 180 };