elf/sln.c

   1 /* `sln' program to create symbolic links between files.
   2    Copyright (C) 1998-2023 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, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <error.h>
  20 #include <errno.h>
  21 #include <libintl.h>
  22 #include <locale.h>
  23 #include <sys/types.h>
  24 #include <sys/stat.h>
  25 #include <unistd.h>
  26 #include <errno.h>
  27 #include <ctype.h>
  28 #include <stdio.h>
  29 #include <string.h>
  30 #include <limits.h>
  31
  32 #include "../version.h"
  33
  34 #define PACKAGE _libc_intl_domainname
  35
  36 static int makesymlink (const char *src, const char *dest);
  37 static int makesymlinks (const char *file);
  38 static void usage (void);
  39
  40 int
  41 main (int argc, char **argv)
  42 {
  43   /* Set locale via LC_ALL.  */
  44   setlocale (LC_ALL, "");
  45
  46   /* Set the text message domain.  */
  47   textdomain (PACKAGE);
  48
  49   switch (argc)
  50     {
  51     case 2:
  52       if (strcmp (argv[1], "--version") == 0) {
  53         printf ("sln %s%s\n", PKGVERSION, VERSION);
  54         return 0;
  55       } else if (strcmp (argv[1], "--help") == 0) {
  56         usage ();
  57         return 0;
  58       }
  59       return makesymlinks (argv [1]);
  60       break;
  61
  62     case 3:
  63       return makesymlink (argv [1], argv [2]);
  64       break;
  65
  66     default:
  67       usage ();
  68       return 1;
  69       break;
  70     }
  71 }
  72
  73 static void
  74 usage (void)
  75 {
  76   printf (_("Usage: sln src dest|file\n\n"));
  77   printf (_("For bug reporting instructions, please see:\n\
  78 %s.\n"), REPORT_BUGS_TO);
  79 }
  80
  81 static int
  82 makesymlinks (const char *file)
  83 {
  84   char *buffer = NULL;
  85   size_t bufferlen = 0;
  86   int ret;
  87   int lineno;
  88   FILE *fp;
  89
  90   if (strcmp (file, "-") == 0)
  91     fp = stdin;
  92   else
  93     {
  94       fp = fopen (file, "r");
  95       if (fp == NULL)
  96         {
  97           fprintf (stderr, _("%s: file open error: %m\n"), file);
  98           return 1;
  99         }
 100     }
 101
 102   ret = 0;
 103   lineno = 0;
 104   while (!feof_unlocked (fp))
 105     {
 106       ssize_t n = getline (&buffer, &bufferlen, fp);
 107       char *src;
 108       char *dest;
 109       char *cp = buffer;
 110
 111       if (n < 0)
 112         break;
 113       if (buffer[n - 1] == '\n')
 114         buffer[n - 1] = '\0';
 115
 116       ++lineno;
 117       while (isspace (*cp))
 118         ++cp;
 119       if (*cp == '\0')
 120         /* Ignore empty lines.  */
 121         continue;
 122       src = cp;
 123
 124       do
 125         ++cp;
 126       while (*cp != '\0' && ! isspace (*cp));
 127       if (*cp != '\0')
 128         *cp++ = '\0';
 129
 130       while (isspace (*cp))
 131         ++cp;
 132       if (*cp == '\0')
 133         {
 134           fprintf (stderr, _("No target in line %d\n"), lineno);
 135           ret = 1;
 136           continue;
 137         }
 138       dest = cp;
 139
 140       do
 141         ++cp;
 142       while (*cp != '\0' && ! isspace (*cp));
 143       if (*cp != '\0')
 144         *cp++ = '\0';
 145
 146       ret |= makesymlink (src, dest);
 147     }
 148   fclose (fp);
 149
 150   return ret;
 151 }
 152
 153 static int
 154 makesymlink (const char *src, const char *dest)
 155 {
 156   struct stat stats;
 157   const char *error;
 158
 159   /* Destination must not be a directory. */
 160   if (lstat (dest, &stats) == 0)
 161     {
 162       if (S_ISDIR (stats.st_mode))
 163         {
 164           fprintf (stderr, _("%s: destination must not be a directory\n"),
 165                    dest);
 166           return 1;
 167         }
 168       else if (unlink (dest) && errno != ENOENT)
 169         {
 170           fprintf (stderr, _("%s: failed to remove the old destination\n"),
 171                    dest);
 172           return 1;
 173         }
 174     }
 175   else if (errno != ENOENT)
 176     {
 177       error = strerror (errno);
 178       fprintf (stderr, _("%s: invalid destination: %s\n"), dest, error);
 179       return -1;
 180     }
 181
 182   if (symlink (src, dest) == 0)
 183     {
 184       /* Destination must exist by now. */
 185       if (access (dest, F_OK))
 186         {
 187           error = strerror (errno);
 188           unlink (dest);
 189           fprintf (stderr, _("Invalid link from \"%s\" to \"%s\": %s\n"),
 190                    src, dest, error);
 191           return 1;
 192         }
 193       return 0;
 194     }
 195   else
 196     {
 197       error = strerror (errno);
 198       fprintf (stderr, _("Invalid link from \"%s\" to \"%s\": %s\n"),
 199                src, dest, error);
 200       return 1;
 201     }
 202 }