/* Return the canonical absolute name of a given file. Copyright (C) 1996-2005 Free Software Foundation, Inc. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. This program 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 General Public License for more details. You should have received a copy of the GNU General Public License along with this program; see the file COPYING. If not, write to the Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ #ifdef HAVE_CONFIG_H # include #endif #include "canonicalize.h" #ifdef STDC_HEADERS # include #else void free (); #endif #if defined STDC_HEADERS || defined HAVE_STRING_H # include #else # include #endif #if HAVE_SYS_PARAM_H # include #endif #include #if HAVE_UNISTD_H # include #endif #include #include #include "cycle-check.h" #include "filenamecat.h" #include "stat-macros.h" #include "xalloc.h" #include "xgetcwd.h" #ifndef __set_errno # define __set_errno(Val) errno = (Val) #endif #include "pathmax.h" #include "xreadlink.h" #if !HAVE_CANONICALIZE_FILE_NAME /* Return the canonical absolute name of file NAME. A canonical name does not contain any `.', `..' components nor any repeated file name separators ('/') or symlinks. All components must exist. The result is malloc'd. */ char * canonicalize_file_name (const char *name) { # if HAVE_RESOLVEPATH char *resolved, *extra_buf = NULL; size_t resolved_size; ssize_t resolved_len; if (name == NULL) { __set_errno (EINVAL); return NULL; } if (name[0] == '\0') { __set_errno (ENOENT); return NULL; } /* All known hosts with resolvepath (e.g. Solaris 7) don't turn relative names into absolute ones, so prepend the working directory if the file name is not absolute. */ if (name[0] != '/') { char *wd; if (!(wd = xgetcwd ())) return NULL; extra_buf = file_name_concat (wd, name, NULL); name = extra_buf; free (wd); } resolved_size = strlen (name); while (1) { resolved_size = 2 * resolved_size + 1; resolved = xmalloc (resolved_size); resolved_len = resolvepath (name, resolved, resolved_size); if (resolved_len < 0) { free (resolved); free (extra_buf); return NULL; } if (resolved_len < resolved_size) break; free (resolved); } free (extra_buf); /* NUL-terminate the resulting name. */ resolved[resolved_len] = '\0'; return resolved; # else return canonicalize_filename_mode (name, CAN_EXISTING); # endif /* !HAVE_RESOLVEPATH */ } #endif /* !HAVE_CANONICALIZE_FILE_NAME */ /* Return the canonical absolute name of file NAME. A canonical name does not contain any `.', `..' components nor any repeated file name separators ('/') or symlinks. Whether components must exist or not depends on canonicalize mode. The result is malloc'd. */ char * canonicalize_filename_mode (const char *name, canonicalize_mode_t can_mode) { char *rname, *dest, *extra_buf = NULL; char const *start; char const *end; char const *rname_limit; size_t extra_len = 0; struct cycle_check_state cycle_state; if (name == NULL) { __set_errno (EINVAL); return NULL; } if (name[0] == '\0') { __set_errno (ENOENT); return NULL; } if (name[0] != '/') { rname = xgetcwd (); if (!rname) return NULL; dest = strchr (rname, '\0'); if (dest - rname < PATH_MAX) { char *p = xrealloc (rname, PATH_MAX); dest = p + (dest - rname); rname = p; rname_limit = rname + PATH_MAX; } else { rname_limit = dest; } } else { rname = xmalloc (PATH_MAX); rname_limit = rname + PATH_MAX; rname[0] = '/'; dest = rname + 1; } cycle_check_init (&cycle_state); for (start = end = name; *start; start = end) { /* Skip sequence of multiple file name separators. */ while (*start == '/') ++start; /* Find end of component. */ for (end = start; *end && *end != '/'; ++end) /* Nothing. */; if (end - start == 0) break; else if (end - start == 1 && start[0] == '.') /* nothing */; else if (end - start == 2 && start[0] == '.' && start[1] == '.') { /* Back up to previous component, ignore if at root already. */ if (dest > rname + 1) while ((--dest)[-1] != '/'); } else { struct stat st; if (dest[-1] != '/') *dest++ = '/'; if (dest + (end - start) >= rname_limit) { ptrdiff_t dest_offset = dest - rname; size_t new_size = rname_limit - rname; if (end - start + 1 > PATH_MAX) new_size += end - start + 1; else new_size += PATH_MAX; rname = xrealloc (rname, new_size); rname_limit = rname + new_size; dest = rname + dest_offset; } dest = memcpy (dest, start, end - start); dest += end - start; *dest = '\0'; if (lstat (rname, &st) != 0) { if (can_mode == CAN_EXISTING) goto error; if (can_mode == CAN_ALL_BUT_LAST && *end) goto error; st.st_mode = 0; } if (S_ISLNK (st.st_mode)) { char *buf; size_t n, len; if (cycle_check (&cycle_state, &st)) { __set_errno (ELOOP); if (can_mode == CAN_MISSING) continue; else goto error; } buf = xreadlink (rname, st.st_size); if (!buf) { if (can_mode == CAN_MISSING) continue; else goto error; } n = strlen (buf); len = strlen (end); if (!extra_len) { extra_len = ((n + len + 1) > PATH_MAX) ? (n + len + 1) : PATH_MAX; extra_buf = xmalloc (extra_len); } else if ((n + len + 1) > extra_len) { extra_len = n + len + 1; extra_buf = xrealloc (extra_buf, extra_len); } /* Careful here, end may be a pointer into extra_buf... */ memmove (&extra_buf[n], end, len + 1); name = end = memcpy (extra_buf, buf, n); if (buf[0] == '/') dest = rname + 1; /* It's an absolute symlink */ else /* Back up to previous component, ignore if at root already: */ if (dest > rname + 1) while ((--dest)[-1] != '/'); free (buf); } else { if (!S_ISDIR (st.st_mode) && *end && (can_mode != CAN_MISSING)) { errno = ENOTDIR; goto error; } } } } if (dest > rname + 1 && dest[-1] == '/') --dest; *dest = '\0'; free (extra_buf); return rname; error: free (extra_buf); free (rname); return NULL; }