/* * Copyright (c) 2003 Constantin S. Svintsoff * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. The names of the authors may not be used to endorse or promote * products derived from this software without specific prior written * permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #if defined(LIBC_SCCS) && !defined(lint) static char sccsid[] = "@(#)realpath.c 8.1 (Berkeley) 2/16/94"; #endif /* LIBC_SCCS and not lint */ //#include #include //#include "namespace.h" #include #include #include #include #include #include //#include "un-namespace.h" #define FS_SPEC #ifndef PATH_MAX #define PATH_MAX 1024 #endif /* * Find the real name of path, by removing all ".", ".." and symlink * components. Returns (resolved) on success, or (NULL) on failure, * in which case the path which caused trouble is left in (resolved). */ #ifdef FS_SPEC char * fs_spec_realpath(const char * __restrict path, char * __restrict resolved) #else char * realpath(const char * __restrict path, char * __restrict resolved) #endif { struct stat sb; char *p, *q, *s; size_t left_len, resolved_len; unsigned symlinks; int m, slen; char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX]; #ifdef FS_SPEC int serrno = errno; #endif if (path == NULL) { errno = EINVAL; return (NULL); } if (path[0] == '\0') { errno = ENOENT; return (NULL); } if (resolved == NULL) { resolved = malloc(PATH_MAX); if (resolved == NULL) return (NULL); m = 1; } else m = 0; symlinks = 0; if (path[0] == '/') { resolved[0] = '/'; resolved[1] = '\0'; if (path[1] == '\0') return (resolved); resolved_len = 1; left_len = strlcpy(left, path + 1, sizeof(left)); } else { if (getcwd(resolved, PATH_MAX) == NULL) { if (m) free(resolved); else { resolved[0] = '.'; resolved[1] = '\0'; } return (NULL); } resolved_len = strlen(resolved); left_len = strlcpy(left, path, sizeof(left)); } if (left_len >= sizeof(left) || resolved_len >= PATH_MAX) { if (m) free(resolved); errno = ENAMETOOLONG; return (NULL); } /* * Iterate over path components in `left'. */ while (left_len != 0) { /* * Extract the next path component and adjust `left' * and its length. */ p = strchr(left, '/'); s = p ? p : left + left_len; if (s - left >= sizeof(next_token)) { if (m) free(resolved); errno = ENAMETOOLONG; return (NULL); } memcpy(next_token, left, s - left); next_token[s - left] = '\0'; left_len -= s - left; if (p != NULL) memmove(left, s + 1, left_len + 1); if (resolved[resolved_len - 1] != '/') { if (resolved_len + 1 >= PATH_MAX) { if (m) free(resolved); errno = ENAMETOOLONG; return (NULL); } resolved[resolved_len++] = '/'; resolved[resolved_len] = '\0'; } if (next_token[0] == '\0') { /* Handle consequential slashes. */ continue; } else if (strcmp(next_token, ".") == 0) continue; else if (strcmp(next_token, "..") == 0) { /* * Strip the last path component except when we have * single "/" */ if (resolved_len > 1) { resolved[resolved_len - 1] = '\0'; q = strrchr(resolved, '/') + 1; *q = '\0'; resolved_len = q - resolved; } continue; } /* * Append the next path component and lstat() it. */ resolved_len = strlcat(resolved, next_token, PATH_MAX); if (resolved_len >= PATH_MAX) { if (m) free(resolved); errno = ENAMETOOLONG; return (NULL); } if (lstat(resolved, &sb) != 0) { #ifdef FS_SPEC if (errno == ENOENT && p == NULL) { errno = serrno; return (resolved); } #endif if (m) free(resolved); return (NULL); } if (S_ISLNK(sb.st_mode)) { if (symlinks++ > MAXSYMLINKS) { if (m) free(resolved); errno = ELOOP; return (NULL); } slen = readlink(resolved, symlink, sizeof(symlink) - 1); if (slen < 0) { if (m) free(resolved); return (NULL); } symlink[slen] = '\0'; if (symlink[0] == '/') { resolved[1] = 0; resolved_len = 1; } else if (resolved_len > 1) { /* Strip the last path component. */ resolved[resolved_len - 1] = '\0'; q = strrchr(resolved, '/') + 1; *q = '\0'; resolved_len = q - resolved; } /* * If there are any path components left, then * append them to symlink. The result is placed * in `left'. */ if (p != NULL) { if (symlink[slen - 1] != '/') { if (slen + 1 >= sizeof(symlink)) { if (m) free(resolved); errno = ENAMETOOLONG; return (NULL); } symlink[slen] = '/'; symlink[slen + 1] = 0; } left_len = strlcat(symlink, left, sizeof(symlink)); if (left_len >= sizeof(left)) { if (m) free(resolved); errno = ENAMETOOLONG; return (NULL); } } left_len = strlcpy(left, symlink, sizeof(left)); } else if (!S_ISDIR(sb.st_mode) && p != NULL) { if (m) free(resolved); errno = ENOTDIR; return (NULL); } } /* * Remove trailing slash except when the resolved pathname * is a single "/". */ if (resolved_len > 1 && resolved[resolved_len - 1] == '/') resolved[resolved_len - 1] = '\0'; return (resolved); }