/* * 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. * * 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. 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. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 * 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 *rcsid = "$OpenBSD: realpath.c,v 1.10 2003/08/01 21:04:59 millert Exp $"; #endif /* LIBC_SCCS and not lint */ #include #include #include #include #include #include #include /* * char *realpath(const char *path, char resolved_path[MAXPATHLEN]); * * 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; { struct stat sb; int fd, n, needslash, serrno; char *p, *q, wbuf[MAXPATHLEN]; int symlinks = 0; /* Save the starting point. */ if ((fd = open(".", O_RDONLY)) < 0) { (void)strlcpy(resolved, ".", MAXPATHLEN); return (NULL); } /* Convert "." -> "" to optimize away a needless lstat() and chdir() */ if (path[0] == '.' && path[1] == '\0') path = ""; /* * 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. */ strlcpy(resolved, path, MAXPATHLEN); 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; /* 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-1); if (n < 0) goto err1; resolved[n] = '\0'; goto loop; } if (S_ISDIR(sb.st_mode)) { if (chdir(p) < 0) goto err1; p = ""; } } /* * Save the last component name and get the full pathname of * the current directory. */ (void)strlcpy(wbuf, p, sizeof wbuf); 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. */ if (resolved[0] == '/' && resolved[1] == '\0') needslash = 0; else needslash = 1; if (*wbuf) { if (strlen(resolved) + strlen(wbuf) + needslash >= MAXPATHLEN) { errno = ENAMETOOLONG; goto err1; } if (needslash) strlcat(resolved, "/", MAXPATHLEN); strlcat(resolved, wbuf, MAXPATHLEN); } /* Go back to where we came from. */ if (fchdir(fd) < 0) { serrno = errno; goto err2; } /* It's okay if the close fails, what's an fd more or less? */ (void)close(fd); return (resolved); err1: serrno = errno; (void)fchdir(fd); err2: (void)close(fd); errno = serrno; return (NULL); }