1d915a14eSPedro F. Giffuni /*-
2d915a14eSPedro F. Giffuni * SPDX-License-Identifier: BSD-3-Clause
3d915a14eSPedro F. Giffuni *
4226a0f0fSMax Khon * Copyright (c) 2003 Constantin S. Svintsoff <kostik@iclub.nsu.ru>
5d01a28e2SPeter Wemm *
6d01a28e2SPeter Wemm * Redistribution and use in source and binary forms, with or without
7d01a28e2SPeter Wemm * modification, are permitted provided that the following conditions
8d01a28e2SPeter Wemm * are met:
9d01a28e2SPeter Wemm * 1. Redistributions of source code must retain the above copyright
10d01a28e2SPeter Wemm * notice, this list of conditions and the following disclaimer.
11d01a28e2SPeter Wemm * 2. Redistributions in binary form must reproduce the above copyright
12d01a28e2SPeter Wemm * notice, this list of conditions and the following disclaimer in the
13d01a28e2SPeter Wemm * documentation and/or other materials provided with the distribution.
14226a0f0fSMax Khon * 3. The names of the authors may not be used to endorse or promote
15226a0f0fSMax Khon * products derived from this software without specific prior written
16226a0f0fSMax Khon * permission.
17d01a28e2SPeter Wemm *
18226a0f0fSMax Khon * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19d01a28e2SPeter Wemm * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20d01a28e2SPeter Wemm * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21226a0f0fSMax Khon * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22d01a28e2SPeter Wemm * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23d01a28e2SPeter Wemm * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24d01a28e2SPeter Wemm * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25d01a28e2SPeter Wemm * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26d01a28e2SPeter Wemm * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27d01a28e2SPeter Wemm * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28d01a28e2SPeter Wemm * SUCH DAMAGE.
29d01a28e2SPeter Wemm */
30d01a28e2SPeter Wemm
31d201fe46SDaniel Eischen #include "namespace.h"
32d01a28e2SPeter Wemm #include <sys/param.h>
33d01a28e2SPeter Wemm #include <sys/stat.h>
34d01a28e2SPeter Wemm
35d01a28e2SPeter Wemm #include <errno.h>
36839e119eSMax Khon #include <stdlib.h>
37d01a28e2SPeter Wemm #include <string.h>
38d01a28e2SPeter Wemm #include <unistd.h>
390573d0a9SMateusz Guzik #include <fcntl.h>
40d201fe46SDaniel Eischen #include "un-namespace.h"
410573d0a9SMateusz Guzik #include "libc_private.h"
420573d0a9SMateusz Guzik
430573d0a9SMateusz Guzik extern int __realpathat(int fd, const char *path, char *buf, size_t size,
440573d0a9SMateusz Guzik int flags);
45d01a28e2SPeter Wemm
46d01a28e2SPeter Wemm /*
47d01a28e2SPeter Wemm * Find the real name of path, by removing all ".", ".." and symlink
48d01a28e2SPeter Wemm * components. Returns (resolved) on success, or (NULL) on failure,
49d01a28e2SPeter Wemm * in which case the path which caused trouble is left in (resolved).
50d01a28e2SPeter Wemm */
510573d0a9SMateusz Guzik static char * __noinline
realpath1(const char * path,char * resolved)52d933a4c0SKonstantin Belousov realpath1(const char *path, char *resolved)
53d01a28e2SPeter Wemm {
54839e119eSMax Khon struct stat sb;
55f81e5b2dSKonstantin Belousov char *p, *q;
56f81e5b2dSKonstantin Belousov size_t left_len, resolved_len, next_token_len;
57839e119eSMax Khon unsigned symlinks;
58f81e5b2dSKonstantin Belousov ssize_t slen;
59839e119eSMax Khon char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX];
60d01a28e2SPeter Wemm
61839e119eSMax Khon symlinks = 0;
62226a0f0fSMax Khon if (path[0] == '/') {
63839e119eSMax Khon resolved[0] = '/';
64839e119eSMax Khon resolved[1] = '\0';
65226a0f0fSMax Khon if (path[1] == '\0')
66839e119eSMax Khon return (resolved);
67226a0f0fSMax Khon resolved_len = 1;
68d0509082SJacques Vidrine left_len = strlcpy(left, path + 1, sizeof(left));
69226a0f0fSMax Khon } else {
70839e119eSMax Khon if (getcwd(resolved, PATH_MAX) == NULL) {
714e738f5aSKonstantin Belousov resolved[0] = '.';
724e738f5aSKonstantin Belousov resolved[1] = '\0';
73839e119eSMax Khon return (NULL);
74d01a28e2SPeter Wemm }
75839e119eSMax Khon resolved_len = strlen(resolved);
76d0509082SJacques Vidrine left_len = strlcpy(left, path, sizeof(left));
77e53211ceSPoul-Henning Kamp }
78839e119eSMax Khon if (left_len >= sizeof(left) || resolved_len >= PATH_MAX) {
79d01a28e2SPeter Wemm errno = ENAMETOOLONG;
80839e119eSMax Khon return (NULL);
81d01a28e2SPeter Wemm }
82d01a28e2SPeter Wemm
83839e119eSMax Khon /*
84839e119eSMax Khon * Iterate over path components in `left'.
85839e119eSMax Khon */
86839e119eSMax Khon while (left_len != 0) {
87839e119eSMax Khon /*
88839e119eSMax Khon * Extract the next path component and adjust `left'
89839e119eSMax Khon * and its length.
90839e119eSMax Khon */
91839e119eSMax Khon p = strchr(left, '/');
92f81e5b2dSKonstantin Belousov
93df5e3924SAlex Richardson next_token_len = p != NULL ? (size_t)(p - left) : left_len;
94f81e5b2dSKonstantin Belousov memcpy(next_token, left, next_token_len);
95f81e5b2dSKonstantin Belousov next_token[next_token_len] = '\0';
96f81e5b2dSKonstantin Belousov
97f81e5b2dSKonstantin Belousov if (p != NULL) {
98f81e5b2dSKonstantin Belousov left_len -= next_token_len + 1;
99f81e5b2dSKonstantin Belousov memmove(left, p + 1, left_len + 1);
100f81e5b2dSKonstantin Belousov } else {
101f81e5b2dSKonstantin Belousov left[0] = '\0';
102f81e5b2dSKonstantin Belousov left_len = 0;
103839e119eSMax Khon }
104f81e5b2dSKonstantin Belousov
105839e119eSMax Khon if (resolved[resolved_len - 1] != '/') {
106be6a158eSMax Khon if (resolved_len + 1 >= PATH_MAX) {
107226a0f0fSMax Khon errno = ENAMETOOLONG;
108839e119eSMax Khon return (NULL);
109d01a28e2SPeter Wemm }
110839e119eSMax Khon resolved[resolved_len++] = '/';
111839e119eSMax Khon resolved[resolved_len] = '\0';
112226a0f0fSMax Khon }
113fdbe55fcSKonstantin Belousov if (next_token[0] == '\0') {
114310c8f3cSJilles Tjoelker /* Handle consequential slashes. */
115226a0f0fSMax Khon continue;
116cf5cedd7SKonstantin Belousov } else if (strcmp(next_token, ".") == 0) {
117226a0f0fSMax Khon continue;
118cf5cedd7SKonstantin Belousov } else if (strcmp(next_token, "..") == 0) {
119839e119eSMax Khon /*
120839e119eSMax Khon * Strip the last path component except when we have
121839e119eSMax Khon * single "/"
122839e119eSMax Khon */
123226a0f0fSMax Khon if (resolved_len > 1) {
124839e119eSMax Khon resolved[resolved_len - 1] = '\0';
125f4203da8SMax Khon q = strrchr(resolved, '/') + 1;
126226a0f0fSMax Khon *q = '\0';
127839e119eSMax Khon resolved_len = q - resolved;
128226a0f0fSMax Khon }
129226a0f0fSMax Khon continue;
130226a0f0fSMax Khon }
131226a0f0fSMax Khon
132839e119eSMax Khon /*
133fdbe55fcSKonstantin Belousov * Append the next path component and lstat() it.
134839e119eSMax Khon */
135d0509082SJacques Vidrine resolved_len = strlcat(resolved, next_token, PATH_MAX);
136be6a158eSMax Khon if (resolved_len >= PATH_MAX) {
137226a0f0fSMax Khon errno = ENAMETOOLONG;
138839e119eSMax Khon return (NULL);
139226a0f0fSMax Khon }
140d933a4c0SKonstantin Belousov if (lstat(resolved, &sb) != 0)
141839e119eSMax Khon return (NULL);
142839e119eSMax Khon if (S_ISLNK(sb.st_mode)) {
143839e119eSMax Khon if (symlinks++ > MAXSYMLINKS) {
144226a0f0fSMax Khon errno = ELOOP;
145839e119eSMax Khon return (NULL);
146226a0f0fSMax Khon }
147f81e5b2dSKonstantin Belousov slen = readlink(resolved, symlink, sizeof(symlink));
148df5e3924SAlex Richardson if (slen <= 0 || slen >= (ssize_t)sizeof(symlink)) {
149cf5cedd7SKonstantin Belousov if (slen < 0)
150cf5cedd7SKonstantin Belousov ; /* keep errno from readlink(2) call */
151cf5cedd7SKonstantin Belousov else if (slen == 0)
152f81e5b2dSKonstantin Belousov errno = ENOENT;
153cf5cedd7SKonstantin Belousov else
154f81e5b2dSKonstantin Belousov errno = ENAMETOOLONG;
155839e119eSMax Khon return (NULL);
1569d79ec20SKonstantin Belousov }
157226a0f0fSMax Khon symlink[slen] = '\0';
158226a0f0fSMax Khon if (symlink[0] == '/') {
159839e119eSMax Khon resolved[1] = 0;
160226a0f0fSMax Khon resolved_len = 1;
161f81e5b2dSKonstantin Belousov } else {
162839e119eSMax Khon /* Strip the last path component. */
163f4203da8SMax Khon q = strrchr(resolved, '/') + 1;
164226a0f0fSMax Khon *q = '\0';
165839e119eSMax Khon resolved_len = q - resolved;
166226a0f0fSMax Khon }
167226a0f0fSMax Khon
168839e119eSMax Khon /*
169839e119eSMax Khon * If there are any path components left, then
170839e119eSMax Khon * append them to symlink. The result is placed
171839e119eSMax Khon * in `left'.
172839e119eSMax Khon */
173057e4034SMax Khon if (p != NULL) {
174057e4034SMax Khon if (symlink[slen - 1] != '/') {
175df5e3924SAlex Richardson if (slen + 1 >= (ssize_t)sizeof(symlink)) {
176226a0f0fSMax Khon errno = ENAMETOOLONG;
177839e119eSMax Khon return (NULL);
178226a0f0fSMax Khon }
179226a0f0fSMax Khon symlink[slen] = '/';
180226a0f0fSMax Khon symlink[slen + 1] = 0;
181226a0f0fSMax Khon }
18224a92ae0SEd Schouten left_len = strlcat(symlink, left,
18324a92ae0SEd Schouten sizeof(symlink));
184f81e5b2dSKonstantin Belousov if (left_len >= sizeof(symlink)) {
185226a0f0fSMax Khon errno = ENAMETOOLONG;
186839e119eSMax Khon return (NULL);
187226a0f0fSMax Khon }
188057e4034SMax Khon }
189d0509082SJacques Vidrine left_len = strlcpy(left, symlink, sizeof(left));
190310c8f3cSJilles Tjoelker } else if (!S_ISDIR(sb.st_mode) && p != NULL) {
191310c8f3cSJilles Tjoelker errno = ENOTDIR;
192310c8f3cSJilles Tjoelker return (NULL);
193226a0f0fSMax Khon }
194226a0f0fSMax Khon }
195226a0f0fSMax Khon
196839e119eSMax Khon /*
197839e119eSMax Khon * Remove trailing slash except when the resolved pathname
198839e119eSMax Khon * is a single "/".
199839e119eSMax Khon */
200839e119eSMax Khon if (resolved_len > 1 && resolved[resolved_len - 1] == '/')
201839e119eSMax Khon resolved[resolved_len - 1] = '\0';
202839e119eSMax Khon return (resolved);
203d01a28e2SPeter Wemm }
204d933a4c0SKonstantin Belousov
205d933a4c0SKonstantin Belousov char *
realpath(const char * __restrict path,char * __restrict resolved)206d933a4c0SKonstantin Belousov realpath(const char * __restrict path, char * __restrict resolved)
207d933a4c0SKonstantin Belousov {
208d933a4c0SKonstantin Belousov char *m, *res;
209d933a4c0SKonstantin Belousov
210d933a4c0SKonstantin Belousov if (path == NULL) {
211d933a4c0SKonstantin Belousov errno = EINVAL;
212d933a4c0SKonstantin Belousov return (NULL);
213d933a4c0SKonstantin Belousov }
214d933a4c0SKonstantin Belousov if (path[0] == '\0') {
215d933a4c0SKonstantin Belousov errno = ENOENT;
216d933a4c0SKonstantin Belousov return (NULL);
217d933a4c0SKonstantin Belousov }
218d933a4c0SKonstantin Belousov if (resolved != NULL) {
219d933a4c0SKonstantin Belousov m = NULL;
220d933a4c0SKonstantin Belousov } else {
221d933a4c0SKonstantin Belousov m = resolved = malloc(PATH_MAX);
222d933a4c0SKonstantin Belousov if (resolved == NULL)
223d933a4c0SKonstantin Belousov return (NULL);
224d933a4c0SKonstantin Belousov }
2250573d0a9SMateusz Guzik if (__getosreldate() >= 1300080) {
2260573d0a9SMateusz Guzik if (__realpathat(AT_FDCWD, path, resolved, PATH_MAX, 0) == 0)
2270573d0a9SMateusz Guzik return (resolved);
2280573d0a9SMateusz Guzik }
229d933a4c0SKonstantin Belousov res = realpath1(path, resolved);
230d933a4c0SKonstantin Belousov if (res == NULL)
231d933a4c0SKonstantin Belousov free(m);
232d933a4c0SKonstantin Belousov return (res);
233d933a4c0SKonstantin Belousov }
234