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 #include "got_path.h"
31 
32 #ifndef MIN
33 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
34 #endif
35 
36 int
37 got_path_is_absolute(const char *path)
38 {
39 	return path[0] == '/';
40 }
41 
42 char *
43 got_path_get_absolute(const char *relpath) 
44 {
45 	char cwd[PATH_MAX];
46 	char *abspath;
47 
48 	if (getcwd(cwd, sizeof(cwd)) == NULL)
49 		return NULL;
50 
51 	if (asprintf(&abspath, "%s/%s/", cwd, relpath) == -1)
52 		return NULL;
53 
54 	return abspath;
55 }
56 
57 char *
58 got_path_normalize(const char *path)
59 {
60 	char *resolved;
61 
62 	resolved = realpath(path, NULL);
63 	if (resolved == NULL)
64 		return NULL;
65 	
66 	if (!got_path_is_absolute(resolved)) {
67 		char *abspath = got_path_get_absolute(resolved);
68 		free(resolved);
69 		resolved = abspath;
70 	}
71 
72 	return resolved;
73 }
74 
75 /* based on canonpath() from kern_pledge.c */
76 const struct got_error *
77 got_canonpath(const char *input, char *buf, size_t bufsize)
78 {
79 	const char *p;
80 	char *q;
81 
82 	/* can't canon relative paths, don't bother */
83 	if (!got_path_is_absolute(input)) {
84 		if (strlcpy(buf, input, bufsize) >= bufsize)
85 			return got_error(GOT_ERR_NO_SPACE);
86 		return NULL;
87 	}
88 
89 	p = input;
90 	q = buf;
91 	while (*p && (q - buf < bufsize)) {
92 		if (p[0] == '/' && (p[1] == '/' || p[1] == '\0')) {
93 			p += 1;
94 
95 		} else if (p[0] == '/' && p[1] == '.' &&
96 		    (p[2] == '/' || p[2] == '\0')) {
97 			p += 2;
98 
99 		} else if (p[0] == '/' && p[1] == '.' && p[2] == '.' &&
100 		    (p[3] == '/' || p[3] == '\0')) {
101 			p += 3;
102 			if (q != buf)	/* "/../" at start of buf */
103 				while (*--q != '/')
104 					continue;
105 
106 		} else {
107 			*q++ = *p++;
108 		}
109 	}
110 	if ((*p == '\0') && (q - buf < bufsize)) {
111 		*q = 0;
112 		return NULL;
113 	} else
114 		return got_error(GOT_ERR_NO_SPACE);
115 }
116 
117 const struct got_error *
118 got_path_skip_common_ancestor(char **child, const char *parent_abspath,
119     const char *abspath)
120 {
121 	const struct got_error *err = NULL;
122 	size_t len_parent, len, bufsize;
123 
124 	*child = NULL;
125 
126 	len_parent = strlen(parent_abspath);
127 	len = strlen(abspath);
128 	if (len_parent >= len)
129 		return got_error(GOT_ERR_BAD_PATH);
130 	if (strncmp(parent_abspath, abspath, len_parent) != 0)
131 		return got_error(GOT_ERR_BAD_PATH);
132 	if (!got_path_is_root_dir(parent_abspath) && abspath[len_parent] != '/')
133 		return got_error(GOT_ERR_BAD_PATH);
134 	while (abspath[len_parent] == '/')
135 		abspath++;
136 	bufsize = len - len_parent + 1;
137 	*child = malloc(bufsize);
138 	if (*child == NULL)
139 		return got_error_prefix_errno("malloc");
140 	if (strlcpy(*child, abspath + len_parent, bufsize) >= bufsize) {
141 		err = got_error_prefix_errno("strlcpy");
142 		free(*child);
143 		*child = NULL;
144 		return err;
145 	}
146 	return NULL;
147 }
148 
149 int
150 got_path_is_root_dir(const char *path)
151 {
152 	return (path[0] == '/' && path[1] == '\0');
153 }
154 
155 int
156 got_path_is_current_dir(const char *path)
157 {
158 	return (path[0] == '.' && path[1] == '\0');
159 }
160 
161 int
162 got_path_is_child(const char *child, const char *parent, size_t parent_len)
163 {
164 	if (parent_len == 0 || got_path_is_root_dir(parent))
165 		return 1;
166 
167 	if (strncmp(parent, child, parent_len) != 0)
168 		return 0;
169 	if (child[parent_len] != '/')
170 		return 0;
171 
172 	return 1;
173 }
174 
175 int
176 got_path_cmp(const char *path1, const char *path2)
177 {
178 	size_t len1 = strlen(path1);
179 	size_t len2 = strlen(path2);
180 	size_t min_len = MIN(len1, len2);
181 	size_t i = 0;
182 
183 	/* Leading directory separators are insignificant. */
184 	while (path1[0] == '/')
185 		path1++;
186 	while (path2[0] == '/')
187 		path2++;
188 
189 	len1 = strlen(path1);
190 	len2 = strlen(path2);
191 	min_len = MIN(len1, len2);
192 
193 	/* Skip over common prefix. */
194 	while (i < min_len && path1[i] == path2[i])
195 		i++;
196 
197 	/* Are the paths exactly equal (besides path separators)? */
198 	if (len1 == len2 && i >= min_len)
199 		return 0;
200 
201 	/* Skip over redundant trailing path seperators. */
202 	while (path1[i] == '/' && path1[i + 1] == '/')
203 		path1++;
204 	while (path2[i] == '/' && path2[i + 1] == '/')
205 		path2++;
206 
207 	/* Trailing path separators are insignificant. */
208 	if (path1[i] == '/' && path1[i + 1] == '\0' && path2[i] == '\0')
209 		return 0;
210 	if (path2[i] == '/' && path2[i + 1] == '\0' && path1[i] == '\0')
211 		return 0;
212 
213 	/* Order children in subdirectories directly after their parents. */
214 	if (path1[i] == '/' && path2[i] == '\0')
215 		return 1;
216 	if (path2[i] == '/' && path1[i] == '\0')
217 		return -1;
218 	if (path1[i] == '/' && path2[i] != '\0')
219 		return -1;
220 	if (path2[i] == '/' && path1[i] != '\0')
221 		return 1;
222 
223 	/* Next character following the common prefix determines order. */
224 	return (unsigned char)path1[i] < (unsigned char)path2[i] ? -1 : 1;
225 }
226 
227 const struct got_error *
228 got_pathlist_insert(struct got_pathlist_entry **inserted,
229     struct got_pathlist_head *pathlist, const char *path, void *data)
230 {
231 	struct got_pathlist_entry *new, *pe;
232 
233 	if (inserted)
234 		*inserted = NULL;
235 
236 	new = malloc(sizeof(*new));
237 	if (new == NULL)
238 		return got_error_prefix_errno("malloc");
239 	new->path = path;
240 	new->data = data;
241 
242 	/*
243 	 * Many callers will provide paths in a somewhat sorted order while
244 	 * constructing a path list from inputs such as tree objects or
245 	 * dirents. Iterating backwards from the tail of the list should
246 	 * be more efficient than traversing through the entire list each
247 	 * time an element is inserted.
248 	 */
249 	pe = TAILQ_LAST(pathlist, got_pathlist_head);
250 	while (pe) {
251 		int cmp = got_path_cmp(pe->path, path);
252 		if (cmp == 0) {
253 			free(new); /* duplicate */
254 			return NULL;
255 		} else if (cmp < 0) {
256 			TAILQ_INSERT_AFTER(pathlist, pe, new, entry);
257 			if (inserted)
258 				*inserted = new;
259 			return NULL;
260 		}
261 		pe = TAILQ_PREV(pe, got_pathlist_head, entry);
262 	}
263 
264 	TAILQ_INSERT_HEAD(pathlist, new, entry);
265 	if (inserted)
266 		*inserted = new;
267 	return NULL;
268 }
269 
270 void
271 got_pathlist_free(struct got_pathlist_head *pathlist)
272 {
273 	struct got_pathlist_entry *pe;
274 
275 	while ((pe = TAILQ_FIRST(pathlist)) != NULL) {
276 		TAILQ_REMOVE(pathlist, pe, entry);
277 		free(pe);
278 	}
279 }
280 
281 static const struct got_error *
282 make_parent_dirs(const char *abspath)
283 {
284 	const struct got_error *err = NULL;
285 	char *parent;
286 
287 	err = got_path_dirname(&parent, abspath);
288 	if (err)
289 		return err;
290 
291 	if (mkdir(parent, GOT_DEFAULT_DIR_MODE) == -1) {
292 		if (errno == ENOENT) {
293 			err = make_parent_dirs(parent);
294 			if (err)
295 				goto done;
296 			if (mkdir(parent, GOT_DEFAULT_DIR_MODE) == -1) {
297 				err = got_error_prefix_errno2("mkdir", parent);
298 				goto done;
299 			}
300 		} else
301 			err = got_error_prefix_errno2("mkdir", parent);
302 	}
303 done:
304 	free(parent);
305 	return err;
306 }
307 
308 const struct got_error *
309 got_path_mkdir(const char *abspath)
310 {
311 	const struct got_error *err = NULL;
312 
313 	if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1) {
314 		if (errno == ENOENT) {
315 			err = make_parent_dirs(abspath);
316 			if (err)
317 				goto done;
318 			if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1)
319 				err = got_error_prefix_errno2("mkdir", abspath);
320 		} else
321 			err = got_error_prefix_errno2("mkdir", abspath);
322 	}
323 
324 done:
325 	return err;
326 }
327 
328 const struct got_error *
329 got_path_dirname(char **parent, const char *path)
330 {
331 	char *p;
332 
333 	p = dirname(path);
334 	if (p == NULL)
335 		return got_error_prefix_errno2("dirname", path);
336 
337 	if (p[0] == '.' && p[1] == '\0')
338 		return got_error(GOT_ERR_BAD_PATH);
339 
340 	*parent = strdup(p);
341 	if (*parent == NULL)
342 		return got_error_prefix_errno("strdup");
343 
344 	return NULL;
345 }
346 
347 void
348 got_path_strip_trailing_slashes(char *path)
349 {
350 	int x;
351 
352 	while (path[x = strlen(path) - 1] == '/')
353 		path[x] = '\0';
354 }