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From Dmitry Levin.
This commit is contained in:
Jim Meyering
parent
c600ace840
commit
eb04d885c2
291
lib/canonicalize.c
Normal file
291
lib/canonicalize.c
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/* Return the canonical absolute name of a given file.
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Copyright (C) 1996-2001, 2002, 2003 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; see the file COPYING.
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If not, write to the Free Software Foundation,
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59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#ifdef STDC_HEADERS
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# include <stdlib.h>
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#else
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void free ();
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#endif
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#if defined STDC_HEADERS || defined HAVE_STRING_H
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# include <string.h>
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#else
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# include <strings.h>
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#endif
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#if HAVE_SYS_PARAM_H
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# include <sys/param.h>
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#endif
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#include <sys/stat.h>
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#if HAVE_ERRNO_H
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# include <errno.h>
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#endif
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#include "xalloc.h"
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#include "xgetcwd.h"
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#ifndef errno
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extern int errno;
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#endif
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#ifndef __set_errno
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# define __set_errno(Val) errno = (Val)
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#endif
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#if !HAVE_RESOLVEPATH
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# if HAVE_STDDEF_H
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# include <stddef.h>
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# define PTR_INT_TYPE ptrdiff_t
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# else
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# define PTR_INT_TYPE long
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# endif
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# include "pathmax.h"
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# include "xreadlink.h"
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# ifdef STAT_MACROS_BROKEN
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# undef S_ISLNK
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# endif
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# ifndef S_ISLNK
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# ifdef S_IFLNK
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# define S_ISLNK(m) (((m) & S_IFMT) == S_IFLNK)
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# endif
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# endif
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#endif /* !HAVE_RESOLVEPATH */
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/* Return the canonical absolute name of file NAME. A canonical name
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does not contain any `.', `..' components nor any repeated path
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separators ('/') or symlinks. All path components must exist.
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The result is malloc'd. */
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char *
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canonicalize_file_name (const char *name)
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{
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#if HAVE_RESOLVEPATH
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char *resolved, *extra_buf = NULL;
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size_t resolved_size;
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ssize_t resolved_len;
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#else /* !HAVE_RESOLVEPATH */
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char *rpath, *dest, *extra_buf = NULL;
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const char *start, *end, *rpath_limit;
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size_t extra_len = 0;
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int num_links = 0;
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#endif /* !HAVE_RESOLVEPATH */
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if (name == NULL)
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{
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__set_errno (EINVAL);
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return NULL;
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}
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if (name[0] == '\0')
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{
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__set_errno (ENOENT);
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return NULL;
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}
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#if HAVE_RESOLVEPATH
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/* All known hosts with resolvepath (e.g. Solaris 7) don't turn
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relative names into absolute ones, so prepend the working
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directory if the path is not absolute. */
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if (name[0] != '/')
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{
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char *wd;
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if (!(wd = xgetcwd ()));
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return NULL;
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extra_buf = path_concat (wd, name, NULL);
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if (!extra_buf)
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xalloc_die ();
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name = extra_buf;
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free (wd);
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}
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resolved_size = strlen (name);
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while (1)
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{
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resolved_size = 2 * resolved_size + 1;
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resolved = xmalloc (resolved_size);
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resolved_len = resolvepath (name, resolved, resolved_size);
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if (resolved_len < resolved_size)
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break;
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free (resolved);
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}
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if (resolved_len < 0)
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{
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free (resolved);
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resolved = NULL;
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}
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free (extra_buf);
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return resolved;
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#else /* !HAVE_RESOLVEPATH */
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if (name[0] != '/')
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{
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rpath = xgetcwd ();
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if (!rpath)
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return NULL;
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dest = strchr (rpath, '\0');
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if (dest < rpath + PATH_MAX)
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{
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rpath = xrealloc (rpath, PATH_MAX);
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rpath_limit = rpath + PATH_MAX;
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}
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else
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{
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rpath_limit = dest;
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}
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}
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else
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{
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rpath = xmalloc (PATH_MAX);
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rpath_limit = rpath + PATH_MAX;
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rpath[0] = '/';
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dest = rpath + 1;
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}
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for (start = end = name; *start; start = end)
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{
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/* Skip sequence of multiple path-separators. */
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while (*start == '/')
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++start;
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/* Find end of path component. */
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for (end = start; *end && *end != '/'; ++end)
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/* Nothing. */;
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if (end - start == 0)
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break;
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else if (end - start == 1 && start[0] == '.')
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/* nothing */;
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else if (end - start == 2 && start[0] == '.' && start[1] == '.')
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{
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/* Back up to previous component, ignore if at root already. */
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if (dest > rpath + 1)
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while ((--dest)[-1] != '/');
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}
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else
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{
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struct stat st;
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if (dest[-1] != '/')
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*dest++ = '/';
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if (dest + (end - start) >= rpath_limit)
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{
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PTR_INT_TYPE dest_offset = dest - rpath;
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size_t new_size = rpath_limit - rpath;
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if (end - start + 1 > PATH_MAX)
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new_size += end - start + 1;
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else
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new_size += PATH_MAX;
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rpath = (char *) xrealloc (rpath, new_size);
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rpath_limit = rpath + new_size;
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dest = rpath + dest_offset;
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}
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dest = memcpy (dest, start, end - start);
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dest += end - start;
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*dest = '\0';
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if (lstat (rpath, &st) < 0)
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goto error;
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# ifdef S_ISLNK
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if (S_ISLNK (st.st_mode))
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{
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char *buf;
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size_t n, len;
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# ifdef MAXSYMLINKS
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if (++num_links > MAXSYMLINKS)
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{
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__set_errno (ELOOP);
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goto error;
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}
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# endif /* MAXSYMLINKS */
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buf = xreadlink (rpath);
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if (!buf)
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goto error;
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n = strlen (buf);
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len = strlen (end);
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if (!extra_len)
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{
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extra_len =
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((n + len + 1) > PATH_MAX) ? (n + len + 1) : PATH_MAX;
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extra_buf = xmalloc (extra_len);
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}
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else if ((n + len + 1) > extra_len)
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{
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extra_len = n + len + 1;
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extra_buf = xrealloc (extra_buf, extra_len);
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}
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/* Careful here, end may be a pointer into extra_buf... */
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memmove (&extra_buf[n], end, len + 1);
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name = end = memcpy (extra_buf, buf, n);
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if (buf[0] == '/')
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dest = rpath + 1; /* It's an absolute symlink */
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else
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/* Back up to previous component, ignore if at root already: */
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if (dest > rpath + 1)
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while ((--dest)[-1] != '/');
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free (buf);
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}
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# endif /* S_ISLNK */
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}
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}
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if (dest > rpath + 1 && dest[-1] == '/')
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--dest;
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*dest = '\0';
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free (extra_buf);
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return rpath;
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error:
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free (extra_buf);
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free (rpath);
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return NULL;
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#endif /* !HAVE_RESOLVEPATH */
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}
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