elf/sln.c

   1 /* `sln' program to create symbolic links between files.
   2    Copyright (C) 1998, 1999, 2001 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19 \f
  20 #include <error.h>
  21 #include <errno.h>
  22 #include <sys/types.h>
  23 #include <sys/stat.h>
  24 #include <unistd.h>
  25 #include <errno.h>
  26 #include <ctype.h>
  27 #include <stdio.h>
  28 #include <string.h>
  29 #include <limits.h>
  30
  31 #if !defined S_ISDIR && defined S_IFDIR
  32 #define S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
  33 #endif
  34
  35 static int makesymlink (const char *src, const char *dest);
  36 static int makesymlinks (const char *file);
  37
  38 int
  39 main (int argc, char **argv)
  40 {
  41   switch (argc)
  42     {
  43     case 2:
  44       return makesymlinks (argv [1]);
  45       break;
  46
  47     case 3:
  48       return makesymlink (argv [1], argv [2]);
  49       break;
  50
  51     default:
  52       printf ("Usage: %s src dest|file\n", argv [0]);
  53       return 1;
  54       break;
  55     }
  56 }
  57
  58 static int
  59 makesymlinks (file)
  60      const char *file;
  61 {
  62 #ifndef PATH_MAX
  63 #define PATH_MAX 4095
  64 #endif
  65   char *buffer = NULL;
  66   size_t bufferlen = 0;
  67   int ret;
  68   int lineno;
  69   FILE *fp;
  70
  71   if (strcmp (file, "-") == 0)
  72     fp = stdin;
  73   else
  74     {
  75       fp = fopen (file, "r");
  76       if (fp == NULL)
  77         {
  78           fprintf (stderr, "%s: file open error: %m\n", file);
  79           return 1;
  80         }
  81     }
  82
  83   ret = 0;
  84   lineno = 0;
  85   while (!feof_unlocked (fp))
  86     {
  87       ssize_t n = getline (&buffer, &bufferlen, fp);
  88       char *src;
  89       char *dest;
  90       char *cp = buffer;
  91
  92       if (n < 0)
  93         break;
  94       if (buffer[n - 1] == '\n')
  95         buffer[n - 1] = '\0';
  96
  97       ++lineno;
  98       while (isspace (*cp))
  99         ++cp;
 100       if (*cp == '\0')
 101         /* Ignore empty lines.  */
 102         continue;
 103       src = cp;
 104
 105       do
 106         ++cp;
 107       while (*cp != '\0' && ! isspace (*cp));
 108       if (*cp != '\0')
 109         *cp++ = '\0';
 110
 111       while (isspace (*cp))
 112         ++cp;
 113       if (*cp == '\0')
 114         {
 115           fprintf (stderr, "No target in line %d\n", lineno);
 116           ret = 1;
 117           continue;
 118         }
 119       dest = cp;
 120
 121       do
 122         ++cp;
 123       while (*cp != '\0' && ! isspace (*cp));
 124       if (*cp != '\0')
 125         *cp++ = '\0';
 126
 127       ret |= makesymlink (src, dest);
 128     }
 129   fclose (fp);
 130
 131   return ret;
 132 }
 133
 134 static int
 135 makesymlink (src, dest)
 136      const char *src;
 137      const char *dest;
 138 {
 139   struct stat stats;
 140   const char *error;
 141
 142   /* Destination must not be a directory. */
 143   if (lstat (dest, &stats) == 0)
 144     {
 145       if (S_ISDIR (stats.st_mode))
 146         {
 147           fprintf (stderr, "%s: destination must not be a directory\n",
 148                    dest);
 149           return 1;
 150         }
 151       else if (unlink (dest) && errno != ENOENT)
 152         {
 153           fprintf (stderr, "%s: failed to remove the old destination\n",
 154                    dest);
 155           return 1;
 156         }
 157     }
 158   else if (errno != ENOENT)
 159     {
 160       error = strerror (errno);
 161       fprintf (stderr, "%s: invalid destination: %s\n", dest, error);
 162       return -1;
 163     }
 164
 165 #ifdef S_ISLNK
 166   if (symlink (src, dest) == 0)
 167 #else
 168   if (link (src, dest) == 0)
 169 #endif
 170     {
 171       /* Destination must exist by now. */
 172       if (access (dest, F_OK))
 173         {
 174           error = strerror (errno);
 175           unlink (dest);
 176           fprintf (stderr, "Invalid link from \"%s\" to \"%s\": %s\n",
 177                    src, dest, error);
 178           return 1;
 179         }
 180       return 0;
 181     }
 182   else
 183     {
 184       error = strerror (errno);
 185       fprintf (stderr, "Invalid link from \"%s\" to \"%s\": %s\n",
 186                src, dest, error);
 187       return 1;
 188     }
 189 }