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 #include <dirent.h>
29 
30 #include "got_error.h"
31 #include "got_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 (!got_path_is_root_dir(parent_abspath) && 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_prefix_errno("malloc");
141 	if (strlcpy(*child, abspath + len_parent, bufsize) >= bufsize) {
142 		err = got_error_prefix_errno("strlcpy");
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_current_dir(const char *path)
158 {
159 	return (path[0] == '.' && path[1] == '\0');
160 }
161 
162 int
163 got_path_is_child(const char *child, const char *parent, size_t parent_len)
164 {
165 	if (parent_len == 0 || got_path_is_root_dir(parent))
166 		return 1;
167 
168 	if (strncmp(parent, child, parent_len) != 0)
169 		return 0;
170 	if (child[parent_len] != '/')
171 		return 0;
172 
173 	return 1;
174 }
175 
176 int
177 got_path_cmp(const char *path1, const char *path2)
178 {
179 	size_t len1 = strlen(path1);
180 	size_t len2 = strlen(path2);
181 	size_t min_len = MIN(len1, len2);
182 	size_t i = 0;
183 
184 	/* Leading directory separators are insignificant. */
185 	while (path1[0] == '/')
186 		path1++;
187 	while (path2[0] == '/')
188 		path2++;
189 
190 	len1 = strlen(path1);
191 	len2 = strlen(path2);
192 	min_len = MIN(len1, len2);
193 
194 	/* Skip over common prefix. */
195 	while (i < min_len && path1[i] == path2[i])
196 		i++;
197 
198 	/* Are the paths exactly equal (besides path separators)? */
199 	if (len1 == len2 && i >= min_len)
200 		return 0;
201 
202 	/* Skip over redundant trailing path seperators. */
203 	while (path1[i] == '/' && path1[i + 1] == '/')
204 		path1++;
205 	while (path2[i] == '/' && path2[i + 1] == '/')
206 		path2++;
207 
208 	/* Trailing path separators are insignificant. */
209 	if (path1[i] == '/' && path1[i + 1] == '\0' && path2[i] == '\0')
210 		return 0;
211 	if (path2[i] == '/' && path2[i + 1] == '\0' && path1[i] == '\0')
212 		return 0;
213 
214 	/* Order children in subdirectories directly after their parents. */
215 	if (path1[i] == '/' && path2[i] == '\0')
216 		return 1;
217 	if (path2[i] == '/' && path1[i] == '\0')
218 		return -1;
219 	if (path1[i] == '/' && path2[i] != '\0')
220 		return -1;
221 	if (path2[i] == '/' && path1[i] != '\0')
222 		return 1;
223 
224 	/* Next character following the common prefix determines order. */
225 	return (unsigned char)path1[i] < (unsigned char)path2[i] ? -1 : 1;
226 }
227 
228 const struct got_error *
229 got_pathlist_insert(struct got_pathlist_entry **inserted,
230     struct got_pathlist_head *pathlist, const char *path, void *data)
231 {
232 	struct got_pathlist_entry *new, *pe;
233 
234 	if (inserted)
235 		*inserted = NULL;
236 
237 	new = malloc(sizeof(*new));
238 	if (new == NULL)
239 		return got_error_prefix_errno("malloc");
240 	new->path = path;
241 	new->data = data;
242 
243 	/*
244 	 * Many callers will provide paths in a somewhat sorted order while
245 	 * constructing a path list from inputs such as tree objects or
246 	 * dirents. Iterating backwards from the tail of the list should
247 	 * be more efficient than traversing through the entire list each
248 	 * time an element is inserted.
249 	 */
250 	pe = TAILQ_LAST(pathlist, got_pathlist_head);
251 	while (pe) {
252 		int cmp = got_path_cmp(pe->path, path);
253 		if (cmp == 0) {
254 			free(new); /* duplicate */
255 			return NULL;
256 		} else if (cmp < 0) {
257 			TAILQ_INSERT_AFTER(pathlist, pe, new, entry);
258 			if (inserted)
259 				*inserted = new;
260 			return NULL;
261 		}
262 		pe = TAILQ_PREV(pe, got_pathlist_head, entry);
263 	}
264 
265 	TAILQ_INSERT_HEAD(pathlist, new, entry);
266 	if (inserted)
267 		*inserted = new;
268 	return NULL;
269 }
270 
271 void
272 got_pathlist_free(struct got_pathlist_head *pathlist)
273 {
274 	struct got_pathlist_entry *pe;
275 
276 	while ((pe = TAILQ_FIRST(pathlist)) != NULL) {
277 		TAILQ_REMOVE(pathlist, pe, entry);
278 		free(pe);
279 	}
280 }
281 
282 static const struct got_error *
283 make_parent_dirs(const char *abspath)
284 {
285 	const struct got_error *err = NULL;
286 	char *parent;
287 
288 	err = got_path_dirname(&parent, abspath);
289 	if (err)
290 		return err;
291 
292 	if (mkdir(parent, GOT_DEFAULT_DIR_MODE) == -1) {
293 		if (errno == ENOENT) {
294 			err = make_parent_dirs(parent);
295 			if (err)
296 				goto done;
297 			if (mkdir(parent, GOT_DEFAULT_DIR_MODE) == -1) {
298 				err = got_error_prefix_errno2("mkdir", parent);
299 				goto done;
300 			}
301 		} else
302 			err = got_error_prefix_errno2("mkdir", parent);
303 	}
304 done:
305 	free(parent);
306 	return err;
307 }
308 
309 const struct got_error *
310 got_path_mkdir(const char *abspath)
311 {
312 	const struct got_error *err = NULL;
313 
314 	if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1) {
315 		if (errno == ENOENT) {
316 			err = make_parent_dirs(abspath);
317 			if (err)
318 				goto done;
319 			if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1)
320 				err = got_error_prefix_errno2("mkdir", abspath);
321 		} else
322 			err = got_error_prefix_errno2("mkdir", abspath);
323 	}
324 
325 done:
326 	return err;
327 }
328 
329 int
330 got_path_dir_is_empty(const char *dir)
331 {
332 	DIR *d;
333 	struct dirent *dent;
334 	int empty = 1;
335 
336 	d = opendir(dir);
337 	if (d == NULL)
338 		return 1;
339 
340 	while ((dent = readdir(d)) != NULL) {
341 		if (strcmp(dent->d_name, ".") == 0 ||
342 		    strcmp(dent->d_name, "..") == 0)
343 			continue;
344 
345 		empty = 0;
346 		break;
347 	}
348 
349 	closedir(d);
350 	return empty;
351 }
352 
353 const struct got_error *
354 got_path_dirname(char **parent, const char *path)
355 {
356 	char *p;
357 
358 	p = dirname(path);
359 	if (p == NULL)
360 		return got_error_prefix_errno2("dirname", path);
361 
362 	if (p[0] == '.' && p[1] == '\0')
363 		return got_error(GOT_ERR_BAD_PATH);
364 
365 	*parent = strdup(p);
366 	if (*parent == NULL)
367 		return got_error_prefix_errno("strdup");
368 
369 	return NULL;
370 }
371 
372 void
373 got_path_strip_trailing_slashes(char *path)
374 {
375 	int x;
376 
377 	while (path[x = strlen(path) - 1] == '/')
378 		path[x] = '\0';
379 }