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 (argc, argv)
  38      int argc;
  39      char **argv;
  40 {
  41   switch (argc)
  42     {
  43     case 2:
  44       return makesymlinks (argv [1]) == 0 ? 0 : 1;
  45       break;
  46
  47     case 3:
  48       return makesymlink (argv [1], argv [2]) == 0 ? 0 : 1;
  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 [PATH_MAX * 4];
  66   int i, ret, len;
  67   int lineno;
  68   const char *src;
  69   const char *dest;
  70   const char *error;
  71   FILE *fp;
  72
  73   fp = fopen (file, "r");
  74   if (fp == NULL)
  75     {
  76       error = strerror (errno);
  77       fprintf (stderr, "%s: file open error: %s\n", file, error);
  78       return -1;
  79     }
  80
  81   ret = 0;
  82   lineno = 0;
  83   while (fgets (buffer, sizeof (buffer) - 1, fp))
  84     {
  85       lineno++;
  86       src = dest = NULL;
  87       buffer [sizeof (buffer) - 1] = '\0';
  88       len = strlen (buffer);
  89       for (i = 0; i < len && isspace (buffer [i]); i++);
  90       if (i >= len)
  91         {
  92           fprintf (stderr, "Fail to parse line %d: \"%s\"\n", lineno,
  93                    buffer);
  94           ret--;
  95           continue;
  96         }
  97
  98       src = &buffer [i];
  99       for (; i < len && !isspace (buffer [i]); i++);
 100       if (i < len)
 101         {
 102           buffer [i++] = '\0';
 103           for (; i < len && isspace (buffer [i]); i++);
 104           if (i >= len)
 105             {
 106               fprintf (stderr, "No target in line %d: \"%s\"\n", lineno,
 107                        buffer);
 108               ret--;
 109               continue;
 110             }
 111           dest = &buffer [i];
 112           for (; i < len && !isspace (buffer [i]); i++);
 113           buffer [i] = '\0';
 114         }
 115       else
 116         {
 117           fprintf (stderr, "No target in line %d: \"%s\"\n", lineno,
 118                    buffer);
 119           ret--;
 120           continue;
 121         }
 122
 123       if (makesymlink (src, dest))
 124         {
 125           fprintf (stderr, "Failed to make link from \"%s\" to \"%s\" in line %d\n",
 126                    src, dest, lineno);
 127           ret--;
 128         }
 129     }
 130   fclose (fp);
 131
 132   return ret;
 133 }
 134
 135 static int
 136 makesymlink (src, dest)
 137      const char *src;
 138      const char *dest;
 139 {
 140   struct stat stats;
 141   const char *error;
 142
 143   /* Destination must not be a directory. */
 144   if (lstat (dest, &stats) == 0)
 145     {
 146       if (S_ISDIR (stats.st_mode))
 147         {
 148           fprintf (stderr, "%s: destination must not be a directory\n",
 149                    dest);
 150           return -1;
 151         }
 152       else if (unlink (dest) && errno != ENOENT)
 153         {
 154           fprintf (stderr, "%s: failed to remove the old destination\n",
 155                    dest);
 156           return -1;
 157         }
 158     }
 159   else if (errno != ENOENT)
 160     {
 161       error = strerror (errno);
 162       fprintf (stderr, "%s: invalid destination: %s\n", dest, error);
 163       return -1;
 164     }
 165
 166 #ifdef S_ISLNK
 167   if (symlink (src, dest) == 0)
 168 #else
 169   if (link (src, dest) == 0)
 170 #endif
 171     {
 172       /* Destination must exist by now. */
 173       if (access (dest, F_OK))
 174         {
 175           error = strerror (errno);
 176           unlink (dest);
 177           fprintf (stderr, "Invalid link from \"%s\" to \"%s\": %s\n",
 178                    src, dest, error);
 179           return -1;
 180         }
 181       return 0;
 182     }
 183   else
 184     {
 185       error = strerror (errno);
 186       fprintf (stderr, "Invalid link from \"%s\" to \"%s\": %s\n",
 187                src, dest, error);
 188       return -1;
 189     }
 190 }