diff options
Diffstat (limited to 'libc/bionic/realpath.c')
| -rw-r--r-- | libc/bionic/realpath.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/libc/bionic/realpath.c b/libc/bionic/realpath.c new file mode 100644 index 0000000..274a3a0 --- /dev/null +++ b/libc/bionic/realpath.c @@ -0,0 +1,166 @@ +/* + * 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. 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. + * + * 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 sccsid[] = "@(#)realpath.c 8.1 (Berkeley) 2/16/94"; +static char rcsid[] = +"$FreeBSD: /repoman/r/ncvs/src/lib/libc/stdlib/realpath.c,v 1.6.2.1 2003/08/03 23:47:39 nectar Exp $"; +#endif /* LIBC_SCCS and not lint */ + +#include <sys/param.h> +#include <sys/stat.h> + +#include <errno.h> +#include <fcntl.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +/* + * 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, rootd, serrno; + char *p, *q, wbuf[MAXPATHLEN]; + int symlinks = 0; + + /* Save the starting point. */ + if ((fd = open(".", O_RDONLY)) < 0) { + (void)strcpy(resolved, "."); + return (NULL); + } + + /* + * 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; + + /* 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)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. + */ + if (resolved[0] == '/' && resolved[1] == '\0') + rootd = 1; + else + rootd = 0; + + if (*wbuf) { + if (strlen(resolved) + strlen(wbuf) + (1-rootd) + 1 > + MAXPATHLEN) { + errno = ENAMETOOLONG; + goto err1; + } + if (rootd == 0) + (void)strcat(resolved, "/"); + (void)strcat(resolved, wbuf); + } + + /* 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); +} |