diff options
Diffstat (limited to 'lib/util/getcwd.c')
| -rw-r--r-- | lib/util/getcwd.c | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/lib/util/getcwd.c b/lib/util/getcwd.c new file mode 100644 index 0000000..7cfc068 --- /dev/null +++ b/lib/util/getcwd.c @@ -0,0 +1,244 @@ +/* + * SPDX-License-Identifier: BSD-3-Clause + * + * Copyright (c) 1989, 1991, 1993 + * The Regents of the University of California. All rights reserved. + * + * 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. + */ + +#include <config.h> + +#ifndef HAVE_GETCWD + +#include <sys/types.h> +#include <sys/stat.h> + +#include <errno.h> +#include <stdlib.h> +#include <string.h> +#include <dirent.h> +#include <limits.h> + +#include "sudo_compat.h" + +#define ISDOT(dp) \ + (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \ + (dp->d_name[1] == '.' && dp->d_name[2] == '\0'))) + +#if defined(HAVE_STRUCT_DIRENT_D_NAMLEN) && HAVE_STRUCT_DIRENT_D_NAMLEN +# define NAMLEN(dirent) (dirent)->d_namlen +#else +# define NAMLEN(dirent) strlen((dirent)->d_name) +#endif + +char * +sudo_getcwd(char *pt, size_t size) +{ + struct dirent *dp; + DIR *dir = NULL; + dev_t dev; + ino_t ino; + int first; + char *bpt, *bup; + struct stat s; + dev_t root_dev; + ino_t root_ino; + size_t ptsize, upsize; + int save_errno; + char *ept, *eup, *up; + + /* + * If no buffer specified by the user, allocate one as necessary. + * If a buffer is specified, the size has to be non-zero. The path + * is built from the end of the buffer backwards. + */ + if (pt) { + ptsize = 0; + if (!size) { + errno = EINVAL; + return NULL; + } + ept = pt + size; + } else { + if ((pt = malloc(ptsize = 1024 - 4)) == NULL) + return NULL; + ept = pt + ptsize; + } + bpt = ept - 1; + *bpt = '\0'; + + /* + * Allocate bytes (1024 - malloc space) for the string of "../"'s. + * Should always be enough (it's 340 levels). If it's not, allocate + * as necessary. Special * case the first stat, it's ".", not "..". + */ + if ((up = malloc(upsize = 1024 - 4)) == NULL) + goto err; + eup = up + PATH_MAX; + bup = up; + up[0] = '.'; + up[1] = '\0'; + + /* Save root values, so know when to stop. */ + if (stat("/", &s)) + goto err; + root_dev = s.st_dev; + root_ino = s.st_ino; + + errno = 0; /* XXX readdir has no error return. */ + + for (first = 1;; first = 0) { + /* Stat the current level. */ + if (lstat(up, &s)) + goto err; + + /* Save current node values. */ + ino = s.st_ino; + dev = s.st_dev; + + /* Check for reaching root. */ + if (root_dev == dev && root_ino == ino) { + *--bpt = '/'; + /* + * It's unclear that it's a requirement to copy the + * path to the beginning of the buffer, but it's always + * been that way and stuff would probably break. + */ + memcpy(pt, bpt, ept - bpt); + free(up); + return pt; + } + + /* + * Build pointer to the parent directory, allocating memory + * as necessary. Max length is 3 for "../", the largest + * possible component name, plus a trailing NULL. + */ + if (bup + 3 + NAME_MAX + 1 >= eup) { + char *nup; + + if ((nup = reallocarray(up, upsize, 2)) == NULL) + goto err; + upsize *= 2; + up = nup; + bup = up; + eup = up + upsize; + } + *bup++ = '.'; + *bup++ = '.'; + *bup = '\0'; + + /* Open and stat parent directory. */ + if (!(dir = opendir(up)) || fstat(dirfd(dir), &s)) + goto err; + + /* Add trailing slash for next directory. */ + *bup++ = '/'; + + /* + * If it's a mount point, have to stat each element because + * the inode number in the directory is for the entry in the + * parent directory, not the inode number of the mounted file. + */ + save_errno = 0; + if (s.st_dev == dev) { + for (;;) { + if (!(dp = readdir(dir))) + goto notfound; + if (dp->d_fileno == ino) + break; + } + } else + for (;;) { + if (!(dp = readdir(dir))) + goto notfound; + if (ISDOT(dp)) + continue; + memcpy(bup, dp->d_name, NAMLEN(dp) + 1); + + /* Save the first error for later. */ + if (lstat(up, &s)) { + if (!save_errno) + save_errno = errno; + errno = 0; + continue; + } + if (s.st_dev == dev && s.st_ino == ino) + break; + } + + /* + * Check for length of the current name, preceding slash, + * leading slash. + */ + if (bpt - pt <= NAMLEN(dp) + (first ? 1 : 2)) { + size_t len, off; + char *npt; + + if (!ptsize) { + errno = ERANGE; + goto err; + } + off = bpt - pt; + len = ept - bpt; + if ((npt = reallocarray(pt, ptsize, 2)) == NULL) + goto err; + ptsize *= 2; + pt = npt; + bpt = pt + off; + ept = pt + ptsize; + memcpy(ept - len, bpt, len); + bpt = ept - len; + } + if (!first) + *--bpt = '/'; + bpt -= NAMLEN(dp); + memcpy(bpt, dp->d_name, NAMLEN(dp)); + (void)closedir(dir); + + /* Truncate any file name. */ + *bup = '\0'; + } + +notfound: + /* + * If readdir set errno, use it, not any saved error; otherwise, + * didn't find the current directory in its parent directory, set + * errno to ENOENT. + */ + if (!errno) + errno = save_errno ? save_errno : ENOENT; + /* FALLTHROUGH */ +err: + if (ptsize) + free(pt); + if (up) + free(up); + if (dir) + (void)closedir(dir); + return NULL; +} +#endif /* HAVE_GETCWD */ |