diff options
Diffstat (limited to 'realpath.c')
| -rw-r--r-- | realpath.c | 306 |
1 files changed, 155 insertions, 151 deletions
@@ -1,9 +1,6 @@ +/* $OpenBSD: realpath.c,v 1.14 2011/07/24 21:03:00 miod Exp $ */ /* - * Copyright (c) 1994 - * The Regents of the University of California. All rights reserved. - * - * This code is derived from software contributed to Berkeley by - * Jan-Simon Pendry. + * Copyright (c) 2003 Constantin S. Svintsoff <kostik@iclub.nsu.ru> * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions @@ -13,18 +10,14 @@ * 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. All advertising materials mentioning features or use of this software - * must display the following acknowledgement: - * This product includes software developed by the University of - * California, Berkeley and its contributors. - * 4. Neither the name of the University nor the names of its contributors - * may be used to endorse or promote products derived from this software - * without specific prior written permission. + * 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 REGENTS AND CONTRIBUTORS ``AS IS'' AND + * 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 REGENTS OR CONTRIBUTORS BE LIABLE + * 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) @@ -33,176 +26,187 @@ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ -/* $XFree86: xc/programs/xedit/realpath.c,v 1.4 2000/02/12 20:45:45 dawes Exp $ */ - -#if defined(LIBC_SCCS) && !defined(lint) -static char sccsid[] = "@(#)realpath.c 8.1 (Berkeley) 2/16/94"; -#endif /* LIBC_SCCS and not lint */ #include <sys/param.h> -#include <sys/types.h> #include <sys/stat.h> #include <errno.h> -#include <fcntl.h> #include <stdlib.h> #include <string.h> #include <unistd.h> -#ifndef LISP -#include "xedit.h" -#endif - -#if defined(__Lynx__) -#define NO_FCHDIR -#endif - -#if defined(ISC) -#ifndef MAXPATHLEN -#define MAXPATHLEN 1024 -#endif -#endif -#ifndef MAXSYMLINKS -#define MAXSYMLINKS 256 -#endif - /* - * char *realpath(const char *path, char resolved_path[MAXPATHLEN]); + * char *realpath(const char *path, char resolved[PATH_MAX]); * * 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). */ char * -realpath(path, resolved) - const char *path; - char *resolved; +realpath(const char *path, char *resolved) { struct stat sb; -#ifdef NO_FCHDIR - char start[MAXPATHLEN]; -#else - int fd; -#endif - int n, rootd, serrno; - char *p, *q, wbuf[MAXPATHLEN]; - int symlinks = 0; - - /* Save the starting point. */ -#ifdef NO_FCHDIR - if (getcwd(start, MAXPATHLEN) == NULL) { - (void)strcpy(resolved, "."); - return (NULL); - } -#else - if ((fd = open(".", O_RDONLY)) < 0) { - (void)strcpy(resolved, "."); + char *p, *q, *s; + size_t left_len, resolved_len; + unsigned symlinks; + int serrno, slen, mem_allocated; + char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX]; + + if (path[0] == '\0') { + errno = ENOENT; return (NULL); } -#endif - /* - * Find the dirname and basename from the path to be resolved. - * Change directory to the dirname component. - * lstat the basename part. - * if it is a symlink, read in the value and loop. - * if it is a directory, then change to that directory. - * get the current directory name and append the basename. - */ - (void)strncpy(resolved, path, MAXPATHLEN - 1); - resolved[MAXPATHLEN - 1] = '\0'; -loop: - q = strrchr(resolved, '/'); - if (q != NULL) { - p = q + 1; - if (q == resolved) - q = "/"; - else { - do { - --q; - } while (q > resolved && *q == '/'); - q[1] = '\0'; - q = resolved; - } - if (chdir(q) < 0) - goto err1; - } else - p = resolved; + serrno = errno; - /* Deal with the last component. */ - if (*p != '\0' && lstat(p, &sb) == 0) { - if (S_ISLNK(sb.st_mode)) { - if (++symlinks > MAXSYMLINKS) { - errno = ELOOP; - goto err1; - } - n = readlink(p, resolved, MAXPATHLEN); - if (n < 0) - goto err1; - resolved[n] = '\0'; - goto loop; - } - if (S_ISDIR(sb.st_mode)) { - if (chdir(p) < 0) - goto err1; - p = ""; + if (resolved == NULL) { + resolved = malloc(PATH_MAX); + if (resolved == NULL) + return (NULL); + mem_allocated = 1; + } else + mem_allocated = 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 (mem_allocated) + free(resolved); + else + strlcpy(resolved, ".", PATH_MAX); + return (NULL); } + resolved_len = strlen(resolved); + left_len = strlcpy(left, path, sizeof(left)); + } + if (left_len >= sizeof(left) || resolved_len >= PATH_MAX) { + errno = ENAMETOOLONG; + goto err; } /* - * Save the last component name and get the full pathname of - * the current directory. - */ - (void)strcpy(wbuf, p); - if (getcwd(resolved, MAXPATHLEN) == 0) - goto err1; - - /* - * Join the two strings together, ensuring that the right thing - * happens if the last component is empty, or the dirname is root. + * Iterate over path components in `left'. */ - if (resolved[0] == '/' && resolved[1] == '\0') - rootd = 1; - else - rootd = 0; - - if (*wbuf) { - if (strlen(resolved) + strlen(wbuf) + rootd + 1 > MAXPATHLEN) { + 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)) { errno = ENAMETOOLONG; - goto err1; + goto err; + } + 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) { + errno = ENAMETOOLONG; + goto err; + } + resolved[resolved_len++] = '/'; + resolved[resolved_len] = '\0'; + } + if (next_token[0] == '\0') + 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; } - if (rootd == 0) - (void)strcat(resolved, "/"); - (void)strcat(resolved, wbuf); - } - /* Go back to where we came from. */ -#ifdef NO_FCHDIR - if (chdir(start) < 0) -#else - if (fchdir(fd) < 0) -#endif - { - serrno = errno; - goto err2; + /* + * Append the next path component and lstat() it. If + * lstat() fails we still can return successfully if + * there are no more path components left. + */ + resolved_len = strlcat(resolved, next_token, PATH_MAX); + if (resolved_len >= PATH_MAX) { + errno = ENAMETOOLONG; + goto err; + } + if (lstat(resolved, &sb) != 0) { + if (errno == ENOENT && p == NULL) { + errno = serrno; + return (resolved); + } + goto err; + } + if (S_ISLNK(sb.st_mode)) { + if (symlinks++ > MAXSYMLINKS) { + errno = ELOOP; + goto err; + } + slen = readlink(resolved, symlink, sizeof(symlink) - 1); + if (slen < 0) + goto err; + 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)) { + errno = ENAMETOOLONG; + goto err; + } + symlink[slen] = '/'; + symlink[slen + 1] = 0; + } + left_len = strlcat(symlink, left, sizeof(left)); + if (left_len >= sizeof(left)) { + errno = ENAMETOOLONG; + goto err; + } + } + left_len = strlcpy(left, symlink, sizeof(left)); + } } - /* It's okay if the close fails, what's an fd more or less? */ -#ifndef NO_FCHDIR - (void)close(fd); -#endif + /* + * 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); -err1: serrno = errno; -#ifdef NO_FCHDIR - (void)chdir(start); -#else - (void)fchdir(fd); -#endif -err2: -#ifndef NO_FCHDIR - (void)close(fd); -#endif - errno = serrno; +err: + if (mem_allocated) + free(resolved); return (NULL); } |