Program to generate symbolic links.

elf/sln.c

@@ -0,0 +1,190 @@
+/* `sln' program to create symboblic links between files.
+   Copyright (C) 1998 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <errno.h>
+#include <ctype.h>
+#include <stdio.h>
+#include <string.h>
+#include <limits.h>
+
+#if !defined(S_ISDIR) && defined(S_IFDIR)
+#define	S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
+#endif
+
+static int makesymlink __P ((const char *src, const char *dest));
+static int makesymlinks __P ((const char *file));
+
+int
+main (argc, argv)
+     int argc;
+     char **argv;
+{
+  switch (argc)
+    {
+    case 2:
+      return makesymlinks (argv [1]) == 0 ? 0 : 1;
+      break;
+
+    case 3:
+      return makesymlink (argv [1], argv [2]) == 0 ? 0 : 1;
+      break;
+
+    default:
+      printf ("Usage: %s src dest|file\n", argv [0]);
+      return 1;
+      break;
+    }
+}
+
+static int
+makesymlinks (file)
+     const char *file;
+{
+#ifndef PATH_MAX
+#define PATH_MAX 4095
+#endif
+  char buffer [PATH_MAX * 4];
+  int i, ret, len;
+  int lineno;
+  const char *src;
+  const char *dest;
+  const char *error;
+  FILE *fp;
+
+  fp = fopen (file, "r");
+  if (fp == NULL)
+    {
+      error = strerror (errno);
+      fprintf (stderr, "%s: file open error: %s\n", file, error);
+      return -1;
+    }
+
+  ret = 0;
+  lineno = 0;
+  while (fgets (buffer, sizeof (buffer) - 1, fp))
+    {
+      lineno++;
+      src = dest = NULL;
+      buffer [sizeof (buffer) - 1] = '\0';
+      len = strlen (buffer);
+      for (i = 0; i < len && isspace (buffer [i]); i++);
+      if (i >= len)
+        {
+	  fprintf (stderr, "Fail to parse line %d: \"%s\"\n", lineno,
+	  	   buffer);
+	  ret--;
+	  continue;
+	}
+
+      src = &buffer [i];
+      for (; i < len && !isspace (buffer [i]); i++);
+      if (i < len)
+	{
+	  buffer [i++] = '\0';
+	  for (; i < len && isspace (buffer [i]); i++);
+	  if (i >= len)
+	    {
+	      fprintf (stderr, "No target in line %d: \"%s\"\n", lineno,
+	      	       buffer);
+	      ret--;
+	      continue;
+	    }
+	  dest = &buffer [i];
+	  for (; i < len && !isspace (buffer [i]); i++);
+	  buffer [i] = '\0';
+	}
+      else
+        {
+	  fprintf (stderr, "No target in line %d: \"%s\"\n", lineno,
+	  	   buffer);
+	  ret--;
+	  continue;
+	}
+
+      if (makesymlink (src, dest))
+        {
+	  fprintf (stderr, "Failed to make link from \"%s\" to \"%s\" in line %d\n",
+	  	   src, dest, lineno);
+	  ret--;
+	}
+    }
+  fclose (fp);
+
+  return ret;
+}
+
+static int
+makesymlink (src, dest)
+     const char *src;
+     const char *dest;
+{
+  struct stat stats;
+  const char *error;
+
+  /* Destination must not be a directory. */
+  if (lstat (dest, &stats) == 0)
+    {
+      if (S_ISDIR (stats.st_mode))
+	{
+	  fprintf (stderr, "%s: destination must not be a directory\n",
+	  	   dest);
+	  return -1;
+	}
+      else if (unlink (dest) && errno != ENOENT)
+	{
+	  fprintf (stderr, "%s: failed to remove the old destination\n",
+	  	   dest);
+	  return -1;
+	}
+    }
+  else if (errno != ENOENT)
+    {
+      error = strerror (errno);
+      fprintf (stderr, "%s: invalid destination: %s\n", dest, error);
+      return -1;
+    }
+       
+#ifdef S_ISLNK
+  if (symlink (src, dest) == 0)
+#else
+  if (link (src, dest) == 0)
+#endif
+    {
+      /* Destination must exist by now. */
+      if (access (dest, F_OK))
+        {
+	  error = strerror (errno);
+	  unlink (dest);
+	  fprintf (stderr, "Invalid link from \"%s\" to \"%s\": %s\n",
+	  	   src, dest, error);
+	  return -1;
+	}
+      return 0;
+    }
+  else
+    {
+      error = strerror (errno);
+      fprintf (stderr, "Invalid link from \"%s\" to \"%s\": %s\n",
+      	       src, dest, error);
+      return -1;
+    }
+}