elf/sln.c

   1 /* `sln' program to create symboblic links between files.
   2    Copyright (C) 1998 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 Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    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    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19 \f
  20 #include <sys/types.h>
  21 #include <sys/stat.h>
  22 #include <unistd.h>
  23 #include <errno.h>
  24 #include <ctype.h>
  25 #include <stdio.h>
  26 #include <string.h>
  27 #include <limits.h>
  28
  29 #if !defined(S_ISDIR) && defined(S_IFDIR)
  30 #define S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
  31 #endif
  32
  33 static int makesymlink __P ((const char *src, const char *dest));
  34 static int makesymlinks __P ((const char *file));
  35
  36 int
  37 main (int argc, char **argv)
  38 {
  39   switch (argc)
  40     {
  41     case 2:
  42       return makesymlinks (argv [1]) == 0 ? 0 : 1;
  43       break;
  44
  45     case 3:
  46       return makesymlink (argv [1], argv [2]) == 0 ? 0 : 1;
  47       break;
  48
  49     default:
  50       printf ("Usage: %s src dest|file\n", argv [0]);
  51       return 1;
  52       break;
  53     }
  54 }
  55
  56 static int
  57 makesymlinks (file)
  58      const char *file;
  59 {
  60 #ifndef PATH_MAX
  61 #define PATH_MAX 4095
  62 #endif
  63   char buffer [PATH_MAX * 4];
  64   int i, ret, len;
  65   int lineno;
  66   const char *src;
  67   const char *dest;
  68   const char *error;
  69   FILE *fp;
  70
  71   fp = fopen (file, "r");
  72   if (fp == NULL)
  73     {
  74       error = strerror (errno);
  75       fprintf (stderr, "%s: file open error: %s\n", file, error);
  76       return -1;
  77     }
  78
  79   ret = 0;
  80   lineno = 0;
  81   while (fgets (buffer, sizeof (buffer) - 1, fp))
  82     {
  83       lineno++;
  84       src = dest = NULL;
  85       buffer [sizeof (buffer) - 1] = '\0';
  86       len = strlen (buffer);
  87       for (i = 0; i < len && isspace (buffer [i]); i++);
  88       if (i >= len)
  89         {
  90           fprintf (stderr, "Fail to parse line %d: \"%s\"\n", lineno,
  91                    buffer);
  92           ret--;
  93           continue;
  94         }
  95
  96       src = &buffer [i];
  97       for (; i < len && !isspace (buffer [i]); i++);
  98       if (i < len)
  99         {
 100           buffer [i++] = '\0';
 101           for (; i < len && isspace (buffer [i]); i++);
 102           if (i >= len)
 103             {
 104               fprintf (stderr, "No target in line %d: \"%s\"\n", lineno,
 105                        buffer);
 106               ret--;
 107               continue;
 108             }
 109           dest = &buffer [i];
 110           for (; i < len && !isspace (buffer [i]); i++);
 111           buffer [i] = '\0';
 112         }
 113       else
 114         {
 115           fprintf (stderr, "No target in line %d: \"%s\"\n", lineno,
 116                    buffer);
 117           ret--;
 118           continue;
 119         }
 120
 121       if (makesymlink (src, dest))
 122         {
 123           fprintf (stderr, "Failed to make link from \"%s\" to \"%s\" in line %d\n",
 124                    src, dest, lineno);
 125           ret--;
 126         }
 127     }
 128   fclose (fp);
 129
 130   return ret;
 131 }
 132
 133 static int
 134 makesymlink (src, dest)
 135      const char *src;
 136      const char *dest;
 137 {
 138   struct stat stats;
 139   const char *error;
 140
 141   /* Destination must not be a directory. */
 142   if (lstat (dest, &stats) == 0)
 143     {
 144       if (S_ISDIR (stats.st_mode))
 145         {
 146           fprintf (stderr, "%s: destination must not be a directory\n",
 147                    dest);
 148           return -1;
 149         }
 150       else if (unlink (dest) && errno != ENOENT)
 151         {
 152           fprintf (stderr, "%s: failed to remove the old destination\n",
 153                    dest);
 154           return -1;
 155         }
 156     }
 157   else if (errno != ENOENT)
 158     {
 159       error = strerror (errno);
 160       fprintf (stderr, "%s: invalid destination: %s\n", dest, error);
 161       return -1;
 162     }
 163
 164 #ifdef S_ISLNK
 165   if (symlink (src, dest) == 0)
 166 #else
 167   if (link (src, dest) == 0)
 168 #endif
 169     {
 170       /* Destination must exist by now. */
 171       if (access (dest, F_OK))
 172         {
 173           error = strerror (errno);
 174           unlink (dest);
 175           fprintf (stderr, "Invalid link from \"%s\" to \"%s\": %s\n",
 176                    src, dest, error);
 177           return -1;
 178         }
 179       return 0;
 180     }
 181   else
 182     {
 183       error = strerror (errno);
 184       fprintf (stderr, "Invalid link from \"%s\" to \"%s\": %s\n",
 185                src, dest, error);
 186       return -1;
 187     }
 188 }