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Diffstat (limited to 'contrib/ntp/libntp/ntp_realpath.c')
| -rw-r--r-- | contrib/ntp/libntp/ntp_realpath.c | 280 |
1 files changed, 280 insertions, 0 deletions
diff --git a/contrib/ntp/libntp/ntp_realpath.c b/contrib/ntp/libntp/ntp_realpath.c new file mode 100644 index 000000000000..90e5a0d59e75 --- /dev/null +++ b/contrib/ntp/libntp/ntp_realpath.c @@ -0,0 +1,280 @@ +/* + * ntp_realpath.c - get real path for a file + * Juergen Perlinger (perlinger@ntp.org) for the NTP project. + * Feb 11, 2014 for the NTP project. + * + * This is a butchered version of FreeBSD's implementation of 'realpath()', + * and the following copyright applies: + *---------------------------------------------------------------------- + */ + +/*- + * 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. + */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif +#include "ntp_stdlib.h" + +/* ================================================================== */ +#if defined(SYS_WINNT) +/* ================================================================== */ + +#include <stdlib.h> + +/* On Windows, we assume 2k for a file path is enough. */ +#define NTP_PATH_MAX 2048 + +static char * +realpath1(const char *path, char *resolved) +{ + /* Items in the device name space get passed back AS IS. Everything + * else is fed through '_fullpath()', which is probably the closest + * counterpart to what 'realpath()' is expected to do on Windows... + */ + char * retval = NULL; + + if (!strncmp(path, "\\\\.\\", 4)) { + if (strlcpy(resolved, path, NTP_PATH_MAX) >= NTP_PATH_MAX) + errno = ENAMETOOLONG; + else + retval = resolved; + } else if ((retval = _fullpath(resolved, path, NTP_PATH_MAX)) == NULL) { + errno = ENAMETOOLONG; + } + return retval; +} + +/* ================================================================== */ +#elif !defined(HAVE_FUNC_POSIX_REALPATH) +/* ================================================================== */ + +#include <sys/stat.h> +#include <errno.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <fcntl.h> + +/* The following definitions are to avoid system settings with excessive + * values for maxmimum path length and symlink chains/loops. Adjust with + * care, if that's ever needed: some buffers are on the stack! + */ +#define NTP_PATH_MAX 1024 +#define NTP_MAXSYMLINKS 16 + +/* + * 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 * +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[NTP_PATH_MAX], next_token[NTP_PATH_MAX], link_tgt[NTP_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, NTP_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 >= NTP_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 >= NTP_PATH_MAX) { + errno = ENAMETOOLONG; + return (NULL); + } + resolved[resolved_len++] = '/'; + resolved[resolved_len] = '\0'; + } + if ('\0' == next_token[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, NTP_PATH_MAX); + if (resolved_len >= NTP_PATH_MAX) { + errno = ENAMETOOLONG; + return (NULL); + } + if (lstat(resolved, &sb) != 0) + return (NULL); + if (S_ISLNK(sb.st_mode)) { + if (++symlinks > NTP_MAXSYMLINKS) { + errno = ELOOP; + return (NULL); + } + slen = readlink(resolved, link_tgt, sizeof(link_tgt)); + if (slen <= 0 || slen >= (ssize_t)sizeof(link_tgt)) { + if (slen < 0) { + /* keep errno from readlink(2) call */ + } else if (slen == 0) { + errno = ENOENT; + } else { + errno = ENAMETOOLONG; + } + return (NULL); + } + link_tgt[slen] = '\0'; + if (link_tgt[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 link_tgt. The result is placed + * in `left'. + */ + if (p != NULL) { + if (link_tgt[slen - 1] != '/') { + if (slen + 1 >= (ssize_t)sizeof(link_tgt)) { + errno = ENAMETOOLONG; + return (NULL); + } + link_tgt[slen] = '/'; + link_tgt[slen + 1] = 0; + } + left_len = strlcat(link_tgt, left, + sizeof(link_tgt)); + if (left_len >= sizeof(link_tgt)) { + errno = ENAMETOOLONG; + return (NULL); + } + } + left_len = strlcpy(left, link_tgt, 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); +} + +/* ================================================================== */ +#endif /* !defined(SYS_WINNT) && !defined(HAVE_POSIX_REALPATH) */ +/* ================================================================== */ + +char * +ntp_realpath(const char * path) +{ +# if defined(HAVE_FUNC_POSIX_REALPATH) + + return realpath(path, NULL); + +# else + + char *res = NULL, *m = NULL; + if (path == NULL) + errno = EINVAL; + else if (path[0] == '\0') + errno = ENOENT; + else if ((m = malloc(NTP_PATH_MAX)) == NULL) + errno = ENOMEM; /* MSVCRT malloc does not set this... */ + else if ((res = realpath1(path, m)) == NULL) + free(m); + else + res = realloc(res, strlen(res) + 1); + return (res); + +# endif +} |