1 /*
2  * Copyright (c) 2018, 2019 Stefan Sperling <stsp@openbsd.org>
3  * Copyright (c) 2015 Theo de Raadt <deraadt@openbsd.org>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 #include <sys/queue.h>
19 #include <sys/stat.h>
20 
21 #include <errno.h>
22 #include <limits.h>
23 #include <libgen.h>
24 #include <stdlib.h>
25 #include <unistd.h>
26 #include <stdio.h>
27 #include <string.h>
28 
29 #include "got_error.h"
30 
31 #include "got_lib_path.h"
32 
33 #ifndef MIN
34 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
35 #endif
36 
37 int
38 got_path_is_absolute(const char *path)
39 {
40 	return path[0] == '/';
41 }
42 
43 char *
44 got_path_get_absolute(const char *relpath) 
45 {
46 	char cwd[PATH_MAX];
47 	char *abspath;
48 
49 	if (getcwd(cwd, sizeof(cwd)) == NULL)
50 		return NULL;
51 
52 	if (asprintf(&abspath, "%s/%s/", cwd, relpath) == -1)
53 		return NULL;
54 
55 	return abspath;
56 }
57 
58 char *
59 got_path_normalize(const char *path)
60 {
61 	char *resolved;
62 
63 	resolved = realpath(path, NULL);
64 	if (resolved == NULL)
65 		return NULL;
66 	
67 	if (!got_path_is_absolute(resolved)) {
68 		char *abspath = got_path_get_absolute(resolved);
69 		free(resolved);
70 		resolved = abspath;
71 	}
72 
73 	return resolved;
74 }
75 
76 /* based on canonpath() from kern_pledge.c */
77 const struct got_error *
78 got_canonpath(const char *input, char *buf, size_t bufsize)
79 {
80 	const char *p;
81 	char *q;
82 
83 	/* can't canon relative paths, don't bother */
84 	if (!got_path_is_absolute(input)) {
85 		if (strlcpy(buf, input, bufsize) >= bufsize)
86 			return got_error(GOT_ERR_NO_SPACE);
87 		return NULL;
88 	}
89 
90 	p = input;
91 	q = buf;
92 	while (*p && (q - buf < bufsize)) {
93 		if (p[0] == '/' && (p[1] == '/' || p[1] == '\0')) {
94 			p += 1;
95 
96 		} else if (p[0] == '/' && p[1] == '.' &&
97 		    (p[2] == '/' || p[2] == '\0')) {
98 			p += 2;
99 
100 		} else if (p[0] == '/' && p[1] == '.' && p[2] == '.' &&
101 		    (p[3] == '/' || p[3] == '\0')) {
102 			p += 3;
103 			if (q != buf)	/* "/../" at start of buf */
104 				while (*--q != '/')
105 					continue;
106 
107 		} else {
108 			*q++ = *p++;
109 		}
110 	}
111 	if ((*p == '\0') && (q - buf < bufsize)) {
112 		*q = 0;
113 		return NULL;
114 	} else
115 		return got_error(GOT_ERR_NO_SPACE);
116 }
117 
118 const struct got_error *
119 got_path_skip_common_ancestor(char **child, const char *parent_abspath,
120     const char *abspath)
121 {
122 	const struct got_error *err = NULL;
123 	size_t len_parent, len, bufsize;
124 
125 	len_parent = strlen(parent_abspath);
126 	len = strlen(abspath);
127 	if (len_parent >= len)
128 		return got_error(GOT_ERR_BAD_PATH);
129 	if (strncmp(parent_abspath, abspath, len_parent) != 0)
130 		return got_error(GOT_ERR_BAD_PATH);
131 	if (abspath[len_parent] != '/')
132 		return got_error(GOT_ERR_BAD_PATH);
133 	bufsize = len - len_parent + 1;
134 	*child = malloc(bufsize);
135 	if (*child == NULL)
136 		return got_error_from_errno();
137 	if (strlcpy(*child, abspath + len_parent, bufsize) >= bufsize) {
138 		err = got_error_from_errno();
139 		free(*child);
140 		*child = NULL;
141 		return err;
142 	}
143 	return NULL;
144 }
145 
146 int
147 got_path_is_root_dir(const char *path)
148 {
149 	return (path[0] == '/' && path[1] == '\0');
150 }
151 
152 int
153 got_path_is_child(const char *child, const char *parent, size_t parent_len)
154 {
155 	if (parent_len == 0)
156 		return 1;
157 
158 	if (strncmp(parent, child, parent_len) != 0)
159 		return 0;
160 	if (child[parent_len] != '/')
161 		return 0;
162 
163 	return 1;
164 }
165 
166 int
167 got_path_cmp(const char *path1, const char *path2)
168 {
169 	size_t len1 = strlen(path1);
170 	size_t len2 = strlen(path2);
171 	size_t min_len = MIN(len1, len2);
172 	size_t i = 0;
173 
174 	/* Leading directory separators are insignificant. */
175 	while (path1[0] == '/')
176 		path1++;
177 	while (path2[0] == '/')
178 		path2++;
179 
180 	len1 = strlen(path1);
181 	len2 = strlen(path2);
182 	min_len = MIN(len1, len2);
183 
184 	/* Skip over common prefix. */
185 	while (i < min_len && path1[i] == path2[i])
186 		i++;
187 
188 	/* Are the paths exactly equal (besides path separators)? */
189 	if (len1 == len2 && i >= min_len)
190 		return 0;
191 
192 	/* Skip over redundant trailing path seperators. */
193 	while (path1[i] == '/' && path1[i + 1] == '/')
194 		path1++;
195 	while (path2[i] == '/' && path2[i + 1] == '/')
196 		path2++;
197 
198 	/* Trailing path separators are insignificant. */
199 	if (path1[i] == '/' && path1[i + 1] == '\0' && path2[i] == '\0')
200 		return 0;
201 	if (path2[i] == '/' && path2[i + 1] == '\0' && path1[i] == '\0')
202 		return 0;
203 
204 	/* Order children in subdirectories directly after their parents. */
205 	if (path1[i] == '/' && path2[i] == '\0')
206 		return 1;
207 	if (path2[i] == '/' && path1[i] == '\0')
208 		return -1;
209 	if (path1[i] == '/' && path2[i] != '\0')
210 		return -1;
211 	if (path2[i] == '/' && path1[i] != '\0')
212 		return 1;
213 
214 	/* Next character following the common prefix determines order. */
215 	return (unsigned char)path1[i] < (unsigned char)path2[i] ? -1 : 1;
216 }
217 
218 const struct got_error *
219 got_pathlist_insert(struct got_pathlist_entry **inserted,
220     struct got_pathlist_head *pathlist, const char *path, void *data)
221 {
222 	struct got_pathlist_entry *new, *pe;
223 
224 	if (inserted)
225 		*inserted = NULL;
226 
227 	new = malloc(sizeof(*new));
228 	if (new == NULL)
229 		return got_error_from_errno();
230 	new->path = path;
231 	new->data = data;
232 
233 	/*
234 	 * Many callers will provide paths in a somewhat sorted order while
235 	 * constructing a path list from inputs such as tree objects or
236 	 * dirents. Iterating backwards from the tail of the list should
237 	 * be more efficient than traversing through the entire list each
238 	 * time an element is inserted.
239 	 */
240 	pe = TAILQ_LAST(pathlist, got_pathlist_head);
241 	while (pe) {
242 		int cmp = got_path_cmp(pe->path, path);
243 		if (cmp == 0) {
244 			free(new); /* duplicate */
245 			return NULL;
246 		} else if (cmp < 0) {
247 			TAILQ_INSERT_AFTER(pathlist, pe, new, entry);
248 			if (inserted)
249 				*inserted = new;
250 			return NULL;
251 		}
252 		pe = TAILQ_PREV(pe, got_pathlist_head, entry);
253 	}
254 
255 	TAILQ_INSERT_HEAD(pathlist, new, entry);
256 	if (inserted)
257 		*inserted = new;
258 	return NULL;
259 }
260 
261 void
262 got_pathlist_free(struct got_pathlist_head *pathlist)
263 {
264 	struct got_pathlist_entry *pe;
265 
266 	while ((pe = TAILQ_FIRST(pathlist)) != NULL) {
267 		TAILQ_REMOVE(pathlist, pe, entry);
268 		free(pe);
269 	}
270 }
271 
272 static const struct got_error *
273 make_parent_dirs(const char *abspath)
274 {
275 	const struct got_error *err = NULL;
276 	char *parent;
277 
278 	err = got_path_dirname(&parent, abspath);
279 	if (err)
280 		return err;
281 
282 	if (mkdir(parent, GOT_DEFAULT_DIR_MODE) == -1) {
283 		if (errno == ENOENT) {
284 			err = make_parent_dirs(parent);
285 			if (err)
286 				goto done;
287 			if (mkdir(parent, GOT_DEFAULT_DIR_MODE) == -1) {
288 				err = got_error_from_errno();
289 				goto done;
290 			}
291 		} else
292 			err = got_error_from_errno();
293 	}
294 done:
295 	free(parent);
296 	return err;
297 }
298 
299 const struct got_error *
300 got_path_mkdir(const char *abspath)
301 {
302 	const struct got_error *err = NULL;
303 
304 	if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1) {
305 		if (errno == ENOENT) {
306 			err = make_parent_dirs(abspath);
307 			if (err)
308 				goto done;
309 			if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1)
310 				err = got_error_from_errno();
311 		} else
312 			err = got_error_from_errno();
313 	}
314 
315 done:
316 	return err;
317 }
318 
319 const struct got_error *
320 got_path_dirname(char **parent, const char *path)
321 {
322 	char *p;
323 
324 	p = dirname(path);
325 	if (p == NULL)
326 		return got_error_from_errno();
327 
328 	if (p[0] == '.' && p[1] == '\0')
329 		return got_error(GOT_ERR_BAD_PATH);
330 
331 	*parent = strdup(p);
332 	if (*parent == NULL)
333 		return got_error_from_errno();
334 
335 	return NULL;
336 }