Initial revision

svn path=/trunk/; revision=365

1 files changed, 182 insertions, 0 deletions

diff --git a/support/canonicalize.c b/support/canonicalize.c
new file mode 100644
index 0000000..0985e25
--- /dev/null
+++ b/support/canonicalize.c
@@ -0,0 +1,182 @@
+/* Return the canonical absolute name of a given file.
+   Copyright (C) 1996 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 <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <limits.h>
+#include <sys/param.h>
+#include <sys/stat.h>
+#include <errno.h>
+
+/* Return the canonical absolute name of file NAME.  A canonical name
+   does not contain any `.', `..' components nor any repeated path
+   separators ('/') or symlinks.  All path components must exist.  If
+   RESOLVED is null, the result is malloc'd; otherwise, if the
+   canonical name is PATH_MAX chars or more, returns null with `errno'
+   set to ENAMETOOLONG; if the name fits in fewer than PATH_MAX chars,
+   returns the name in RESOLVED.  If the name cannot be resolved and
+   RESOLVED is non-NULL, it contains the path of the first component
+   that cannot be resolved.  If the path can be resolved, RESOLVED
+   holds the same value as the value returned.  */
+
+static char *
+canonicalize (const char *name, char *resolved)
+{
+  char *rpath, *dest, *extra_buf = NULL;
+  const char *start, *end, *rpath_limit;
+  long int path_max;
+  int num_links = 0;
+
+#ifdef PATH_MAX
+  path_max = PATH_MAX;
+#else
+  path_max = pathconf (name, _PC_PATH_MAX);
+  if (path_max <= 0)
+    path_max = 1024;
+#endif
+
+  rpath = resolved ? __alloca (path_max) : malloc (path_max);
+  rpath_limit = rpath + path_max;
+
+  if (name[0] != '/')
+    {
+      if (!getcwd (rpath, path_max))
+	goto error;
+      dest = strchr (rpath, '\0');
+    }
+  else
+    {
+      rpath[0] = '/';
+      dest = rpath + 1;
+    }
+
+  for (start = end = name; *start; start = end)
+    {
+      struct stat st;
+      int n;
+
+      /* skip sequence of multiple path-separators: */
+      while (*start == '/') ++start;
+
+      /* find end of path component: */
+      for (end = start; *end && *end != '/'; ++end);
+
+      if (end - start == 0)
+	break;
+      else if (strncmp (start, ".", end - start) == 0)
+	/* nothing */;
+      else if (strncmp (start, "..", end - start) == 0) {
+	/* back up to previous component, ignore if at root already: */
+	if (dest > rpath + 1)
+	  while ((--dest)[-1] != '/');
+      } else
+	{
+	  size_t new_size;
+
+	  if (dest[-1] != '/')
+	    *dest++ = '/';
+
+	  if (dest + (end - start) >= rpath_limit)
+	    {
+	      if (resolved)
+		{
+		  __set_errno (ENAMETOOLONG);
+		  goto error;
+		}
+	      new_size = rpath_limit - rpath;
+	      if (end - start + 1 > path_max)
+		new_size += end - start + 1;
+	      else
+		new_size += path_max;
+	      rpath = realloc (rpath, new_size);
+	      rpath_limit = rpath + new_size;
+	      if (!rpath)
+		return NULL;
+	    }
+
+	  memcpy (dest, start, end - start);
+	  dest += end - start;
+	  *dest = '\0';
+
+	  if (__lstat (rpath, &st) < 0)
+	    goto error;
+
+	  if (S_ISLNK (st.st_mode))
+	    {
+	      char *buf = __alloca (path_max);
+
+	      if (++num_links > MAXSYMLINKS)
+		{
+		  __set_errno (ELOOP);
+		  goto error;
+		}
+
+	      n = readlink (rpath, buf, path_max);
+	      if (n < 0)
+		goto error;
+	      buf[n] = '\0';
+
+	      if (!extra_buf)
+		extra_buf = __alloca (path_max);
+
+	      if ((long int) (n + strlen (end)) >= path_max)
+		{
+		  __set_errno (ENAMETOOLONG);
+		  goto error;
+		}
+
+	      /* careful here, end may be a pointer into extra_buf... */
+	      strcat (buf, end);
+	      strcpy (extra_buf, buf);
+	      name = end = extra_buf;
+
+	      if (buf[0] == '/')
+		dest = rpath + 1;	/* it's an absolute symlink */
+	      else
+		/* back up to previous component, ignore if at root already: */
+		if (dest > rpath + 1)
+		  while ((--dest)[-1] != '/');
+	    }
+	  else
+	    num_links = 0;
+	}
+    }
+  if (dest > rpath + 1 && dest[-1] == '/')
+    --dest;
+  *dest = '\0';
+
+  return resolved ? strcpy (resolved, rpath) : rpath;
+
+error:
+  if (resolved)
+    strcpy (resolved, rpath);
+  else
+    free (rpath);
+  return NULL;
+}
+weak_alias (canonicalize, realpath)
+
+
+char *
+canonicalize_file_name (const char *name)
+{
+  return canonicalize (name, NULL);
+}