diff options
Diffstat (limited to 'lib/libc/stdlib/realpath.c')
| -rw-r--r-- | lib/libc/stdlib/realpath.c | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/lib/libc/stdlib/realpath.c b/lib/libc/stdlib/realpath.c new file mode 100644 index 000000000000..4c52b73319ab --- /dev/null +++ b/lib/libc/stdlib/realpath.c @@ -0,0 +1,229 @@ +/*- + * SPDX-License-Identifier: BSD-3-Clause + * + * 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 + * 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. + */ + +#include <sys/param.h> +#include <sys/stat.h> + +#include <errno.h> +#include <fcntl.h> +#include <libsys.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <ssp/ssp.h> + +/* + * 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). + */ +static char * __noinline +realpath1(const char *path, char *resolved) +{ + struct stat sb; + char *p, *q; + size_t left_len, resolved_len, next_token_len; + unsigned symlinks; + ssize_t slen; + char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX]; + + 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) { + 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) { + 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, '/'); + + next_token_len = p != NULL ? (size_t)(p - left) : left_len; + memcpy(next_token, left, next_token_len); + next_token[next_token_len] = '\0'; + + if (p != NULL) { + left_len -= next_token_len + 1; + memmove(left, p + 1, left_len + 1); + } else { + left[0] = '\0'; + left_len = 0; + } + + if (resolved[resolved_len - 1] != '/') { + if (resolved_len + 1 >= PATH_MAX) { + 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) { + errno = ENAMETOOLONG; + return (NULL); + } + if (lstat(resolved, &sb) != 0) + return (NULL); + if (S_ISLNK(sb.st_mode)) { + if (symlinks++ > MAXSYMLINKS) { + errno = ELOOP; + return (NULL); + } + slen = readlink(resolved, symlink, sizeof(symlink)); + if (slen < 0) + return (NULL); + if (slen == 0) { + errno = ENOENT; + return (NULL); + } + if ((size_t)slen >= sizeof(symlink)) { + errno = ENAMETOOLONG; + return (NULL); + } + symlink[slen] = '\0'; + if (symlink[0] == '/') { + resolved[1] = 0; + resolved_len = 1; + } else { + /* Strip the last path component. */ + 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 ((size_t)slen + 1 >= sizeof(symlink)) { + errno = ENAMETOOLONG; + return (NULL); + } + symlink[slen] = '/'; + symlink[slen + 1] = 0; + } + left_len = strlcat(symlink, left, + sizeof(symlink)); + if (left_len >= sizeof(symlink)) { + errno = ENAMETOOLONG; + return (NULL); + } + } + left_len = strlcpy(left, symlink, sizeof(left)); + } else if (!S_ISDIR(sb.st_mode) && p != NULL) { + 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); +} + +char * +__ssp_real(realpath)(const char * __restrict path, char * __restrict resolved) +{ + char *m, *res; + + if (path == NULL) { + errno = EINVAL; + return (NULL); + } + if (path[0] == '\0') { + errno = ENOENT; + return (NULL); + } + if (resolved != NULL) { + m = NULL; + } else { + m = resolved = malloc(PATH_MAX); + if (resolved == NULL) + return (NULL); + } + if (__sys___realpathat(AT_FDCWD, path, resolved, PATH_MAX, 0) == 0) { + return (resolved); + } + res = realpath1(path, resolved); + if (res == NULL) + free(m); + return (res); +} |