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 	*child = NULL;
126 
127 	len_parent = strlen(parent_abspath);
128 	len = strlen(abspath);
129 	if (len_parent >= len)
130 		return got_error(GOT_ERR_BAD_PATH);
131 	if (strncmp(parent_abspath, abspath, len_parent) != 0)
132 		return got_error(GOT_ERR_BAD_PATH);
133 	if (abspath[len_parent] != '/')
134 		return got_error(GOT_ERR_BAD_PATH);
135 	while (abspath[len_parent] == '/')
136 		abspath++;
137 	bufsize = len - len_parent + 1;
138 	*child = malloc(bufsize);
139 	if (*child == NULL)
140 		return got_error_from_errno();
141 	if (strlcpy(*child, abspath + len_parent, bufsize) >= bufsize) {
142 		err = got_error_from_errno();
143 		free(*child);
144 		*child = NULL;
145 		return err;
146 	}
147 	return NULL;
148 }
149 
150 int
151 got_path_is_root_dir(const char *path)
152 {
153 	return (path[0] == '/' && path[1] == '\0');
154 }
155 
156 int
157 got_path_is_child(const char *child, const char *parent, size_t parent_len)
158 {
159 	if (parent_len == 0)
160 		return 1;
161 
162 	if (strncmp(parent, child, parent_len) != 0)
163 		return 0;
164 	if (child[parent_len] != '/')
165 		return 0;
166 
167 	return 1;
168 }
169 
170 int
171 got_path_cmp(const char *path1, const char *path2)
172 {
173 	size_t len1 = strlen(path1);
174 	size_t len2 = strlen(path2);
175 	size_t min_len = MIN(len1, len2);
176 	size_t i = 0;
177 
178 	/* Leading directory separators are insignificant. */
179 	while (path1[0] == '/')
180 		path1++;
181 	while (path2[0] == '/')
182 		path2++;
183 
184 	len1 = strlen(path1);
185 	len2 = strlen(path2);
186 	min_len = MIN(len1, len2);
187 
188 	/* Skip over common prefix. */
189 	while (i < min_len && path1[i] == path2[i])
190 		i++;
191 
192 	/* Are the paths exactly equal (besides path separators)? */
193 	if (len1 == len2 && i >= min_len)
194 		return 0;
195 
196 	/* Skip over redundant trailing path seperators. */
197 	while (path1[i] == '/' && path1[i + 1] == '/')
198 		path1++;
199 	while (path2[i] == '/' && path2[i + 1] == '/')
200 		path2++;
201 
202 	/* Trailing path separators are insignificant. */
203 	if (path1[i] == '/' && path1[i + 1] == '\0' && path2[i] == '\0')
204 		return 0;
205 	if (path2[i] == '/' && path2[i + 1] == '\0' && path1[i] == '\0')
206 		return 0;
207 
208 	/* Order children in subdirectories directly after their parents. */
209 	if (path1[i] == '/' && path2[i] == '\0')
210 		return 1;
211 	if (path2[i] == '/' && path1[i] == '\0')
212 		return -1;
213 	if (path1[i] == '/' && path2[i] != '\0')
214 		return -1;
215 	if (path2[i] == '/' && path1[i] != '\0')
216 		return 1;
217 
218 	/* Next character following the common prefix determines order. */
219 	return (unsigned char)path1[i] < (unsigned char)path2[i] ? -1 : 1;
220 }
221 
222 const struct got_error *
223 got_pathlist_insert(struct got_pathlist_entry **inserted,
224     struct got_pathlist_head *pathlist, const char *path, void *data)
225 {
226 	struct got_pathlist_entry *new, *pe;
227 
228 	if (inserted)
229 		*inserted = NULL;
230 
231 	new = malloc(sizeof(*new));
232 	if (new == NULL)
233 		return got_error_from_errno();
234 	new->path = path;
235 	new->data = data;
236 
237 	/*
238 	 * Many callers will provide paths in a somewhat sorted order while
239 	 * constructing a path list from inputs such as tree objects or
240 	 * dirents. Iterating backwards from the tail of the list should
241 	 * be more efficient than traversing through the entire list each
242 	 * time an element is inserted.
243 	 */
244 	pe = TAILQ_LAST(pathlist, got_pathlist_head);
245 	while (pe) {
246 		int cmp = got_path_cmp(pe->path, path);
247 		if (cmp == 0) {
248 			free(new); /* duplicate */
249 			return NULL;
250 		} else if (cmp < 0) {
251 			TAILQ_INSERT_AFTER(pathlist, pe, new, entry);
252 			if (inserted)
253 				*inserted = new;
254 			return NULL;
255 		}
256 		pe = TAILQ_PREV(pe, got_pathlist_head, entry);
257 	}
258 
259 	TAILQ_INSERT_HEAD(pathlist, new, entry);
260 	if (inserted)
261 		*inserted = new;
262 	return NULL;
263 }
264 
265 void
266 got_pathlist_free(struct got_pathlist_head *pathlist)
267 {
268 	struct got_pathlist_entry *pe;
269 
270 	while ((pe = TAILQ_FIRST(pathlist)) != NULL) {
271 		TAILQ_REMOVE(pathlist, pe, entry);
272 		free(pe);
273 	}
274 }
275 
276 static const struct got_error *
277 make_parent_dirs(const char *abspath)
278 {
279 	const struct got_error *err = NULL;
280 	char *parent;
281 
282 	err = got_path_dirname(&parent, abspath);
283 	if (err)
284 		return err;
285 
286 	if (mkdir(parent, GOT_DEFAULT_DIR_MODE) == -1) {
287 		if (errno == ENOENT) {
288 			err = make_parent_dirs(parent);
289 			if (err)
290 				goto done;
291 			if (mkdir(parent, GOT_DEFAULT_DIR_MODE) == -1) {
292 				err = got_error_from_errno();
293 				goto done;
294 			}
295 		} else
296 			err = got_error_from_errno();
297 	}
298 done:
299 	free(parent);
300 	return err;
301 }
302 
303 const struct got_error *
304 got_path_mkdir(const char *abspath)
305 {
306 	const struct got_error *err = NULL;
307 
308 	if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1) {
309 		if (errno == ENOENT) {
310 			err = make_parent_dirs(abspath);
311 			if (err)
312 				goto done;
313 			if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1)
314 				err = got_error_from_errno();
315 		} else
316 			err = got_error_from_errno();
317 	}
318 
319 done:
320 	return err;
321 }
322 
323 const struct got_error *
324 got_path_dirname(char **parent, const char *path)
325 {
326 	char *p;
327 
328 	p = dirname(path);
329 	if (p == NULL)
330 		return got_error_from_errno();
331 
332 	if (p[0] == '.' && p[1] == '\0')
333 		return got_error(GOT_ERR_BAD_PATH);
334 
335 	*parent = strdup(p);
336 	if (*parent == NULL)
337 		return got_error_from_errno();
338 
339 	return NULL;
340 }