1 /*
2  * Copyright (c) 2018, 2019 Stefan Sperling <stsp@openbsd.org>
3  * Copyright (c) 2015 Theo de Raadt <deraadt@openbsd.org>
4  * Copyright (c) 1997 Todd C. Miller <millert@openbsd.org>
5  *
6  * Permission to use, copy, modify, and distribute this software for any
7  * purpose with or without fee is hereby granted, provided that the above
8  * copyright notice and this permission notice appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17  */
18 
19 #include <sys/queue.h>
20 #include <sys/stat.h>
21 
22 #include <errno.h>
23 #include <fcntl.h>
24 #include <limits.h>
25 #include <libgen.h>
26 #include <stdlib.h>
27 #include <unistd.h>
28 #include <stdio.h>
29 #include <string.h>
30 #include <dirent.h>
31 #include <paths.h>
32 
33 #include "got_error.h"
34 #include "got_path.h"
35 
36 #ifndef MIN
37 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
38 #endif
39 
40 int
41 got_path_is_absolute(const char *path)
42 {
43 	return path[0] == '/';
44 }
45 
46 char *
47 got_path_get_absolute(const char *relpath) 
48 {
49 	char cwd[PATH_MAX];
50 	char *abspath;
51 
52 	if (getcwd(cwd, sizeof(cwd)) == NULL)
53 		return NULL;
54 
55 	if (asprintf(&abspath, "%s/%s/", cwd, relpath) == -1)
56 		return NULL;
57 
58 	return abspath;
59 }
60 
61 char *
62 got_path_normalize(const char *path)
63 {
64 	char *resolved;
65 
66 	resolved = realpath(path, NULL);
67 	if (resolved == NULL)
68 		return NULL;
69 	
70 	if (!got_path_is_absolute(resolved)) {
71 		char *abspath = got_path_get_absolute(resolved);
72 		free(resolved);
73 		resolved = abspath;
74 	}
75 
76 	return resolved;
77 }
78 
79 /* based on canonpath() from kern_pledge.c */
80 const struct got_error *
81 got_canonpath(const char *input, char *buf, size_t bufsize)
82 {
83 	const char *p;
84 	char *q;
85 
86 	/* can't canon relative paths, don't bother */
87 	if (!got_path_is_absolute(input)) {
88 		if (strlcpy(buf, input, bufsize) >= bufsize)
89 			return got_error(GOT_ERR_NO_SPACE);
90 		return NULL;
91 	}
92 
93 	p = input;
94 	q = buf;
95 	while (*p && (q - buf < bufsize)) {
96 		if (p[0] == '/' && (p[1] == '/' || p[1] == '\0')) {
97 			p += 1;
98 
99 		} else if (p[0] == '/' && p[1] == '.' &&
100 		    (p[2] == '/' || p[2] == '\0')) {
101 			p += 2;
102 
103 		} else if (p[0] == '/' && p[1] == '.' && p[2] == '.' &&
104 		    (p[3] == '/' || p[3] == '\0')) {
105 			p += 3;
106 			if (q != buf)	/* "/../" at start of buf */
107 				while (*--q != '/')
108 					continue;
109 
110 		} else {
111 			*q++ = *p++;
112 		}
113 	}
114 	if ((*p == '\0') && (q - buf < bufsize)) {
115 		*q = 0;
116 		return NULL;
117 	} else
118 		return got_error(GOT_ERR_NO_SPACE);
119 }
120 
121 const struct got_error *
122 got_path_skip_common_ancestor(char **child, const char *parent_abspath,
123     const char *abspath)
124 {
125 	const struct got_error *err = NULL;
126 	size_t len_parent, len, bufsize;
127 
128 	*child = NULL;
129 
130 	len_parent = strlen(parent_abspath);
131 	len = strlen(abspath);
132 	if (len_parent >= len)
133 		return got_error(GOT_ERR_BAD_PATH);
134 	if (strncmp(parent_abspath, abspath, len_parent) != 0)
135 		return got_error(GOT_ERR_BAD_PATH);
136 	if (!got_path_is_root_dir(parent_abspath) && abspath[len_parent] != '/')
137 		return got_error(GOT_ERR_BAD_PATH);
138 	while (abspath[len_parent] == '/')
139 		abspath++;
140 	bufsize = len - len_parent + 1;
141 	*child = malloc(bufsize);
142 	if (*child == NULL)
143 		return got_error_from_errno("malloc");
144 	if (strlcpy(*child, abspath + len_parent, bufsize) >= bufsize) {
145 		err = got_error_from_errno("strlcpy");
146 		free(*child);
147 		*child = NULL;
148 		return err;
149 	}
150 	return NULL;
151 }
152 
153 int
154 got_path_is_root_dir(const char *path)
155 {
156 	return (path[0] == '/' && path[1] == '\0');
157 }
158 
159 int
160 got_path_is_current_dir(const char *path)
161 {
162 	return (path[0] == '.' && path[1] == '\0');
163 }
164 
165 int
166 got_path_is_child(const char *child, const char *parent, size_t parent_len)
167 {
168 	if (parent_len == 0 || got_path_is_root_dir(parent))
169 		return 1;
170 
171 	if (strncmp(parent, child, parent_len) != 0)
172 		return 0;
173 	if (child[parent_len] != '/')
174 		return 0;
175 
176 	return 1;
177 }
178 
179 int
180 got_path_cmp(const char *path1, const char *path2)
181 {
182 	size_t len1 = strlen(path1);
183 	size_t len2 = strlen(path2);
184 	size_t min_len = MIN(len1, len2);
185 	size_t i = 0;
186 
187 	/* Leading directory separators are insignificant. */
188 	while (path1[0] == '/')
189 		path1++;
190 	while (path2[0] == '/')
191 		path2++;
192 
193 	len1 = strlen(path1);
194 	len2 = strlen(path2);
195 	min_len = MIN(len1, len2);
196 
197 	/* Skip over common prefix. */
198 	while (i < min_len && path1[i] == path2[i])
199 		i++;
200 
201 	/* Are the paths exactly equal (besides path separators)? */
202 	if (len1 == len2 && i >= min_len)
203 		return 0;
204 
205 	/* Skip over redundant trailing path seperators. */
206 	while (path1[i] == '/' && path1[i + 1] == '/')
207 		path1++;
208 	while (path2[i] == '/' && path2[i + 1] == '/')
209 		path2++;
210 
211 	/* Trailing path separators are insignificant. */
212 	if (path1[i] == '/' && path1[i + 1] == '\0' && path2[i] == '\0')
213 		return 0;
214 	if (path2[i] == '/' && path2[i + 1] == '\0' && path1[i] == '\0')
215 		return 0;
216 
217 	/* Order children in subdirectories directly after their parents. */
218 	if (path1[i] == '/' && path2[i] == '\0')
219 		return 1;
220 	if (path2[i] == '/' && path1[i] == '\0')
221 		return -1;
222 	if (path1[i] == '/' && path2[i] != '\0')
223 		return -1;
224 	if (path2[i] == '/' && path1[i] != '\0')
225 		return 1;
226 
227 	/* Next character following the common prefix determines order. */
228 	return (unsigned char)path1[i] < (unsigned char)path2[i] ? -1 : 1;
229 }
230 
231 const struct got_error *
232 got_pathlist_insert(struct got_pathlist_entry **inserted,
233     struct got_pathlist_head *pathlist, const char *path, void *data)
234 {
235 	struct got_pathlist_entry *new, *pe;
236 
237 	if (inserted)
238 		*inserted = NULL;
239 
240 	new = malloc(sizeof(*new));
241 	if (new == NULL)
242 		return got_error_from_errno("malloc");
243 	new->path = path;
244 	new->data = data;
245 
246 	/*
247 	 * Many callers will provide paths in a somewhat sorted order while
248 	 * constructing a path list from inputs such as tree objects or
249 	 * dirents. Iterating backwards from the tail of the list should
250 	 * be more efficient than traversing through the entire list each
251 	 * time an element is inserted.
252 	 */
253 	pe = TAILQ_LAST(pathlist, got_pathlist_head);
254 	while (pe) {
255 		int cmp = got_path_cmp(pe->path, path);
256 		if (cmp == 0) {
257 			free(new); /* duplicate */
258 			return NULL;
259 		} else if (cmp < 0) {
260 			TAILQ_INSERT_AFTER(pathlist, pe, new, entry);
261 			if (inserted)
262 				*inserted = new;
263 			return NULL;
264 		}
265 		pe = TAILQ_PREV(pe, got_pathlist_head, entry);
266 	}
267 
268 	TAILQ_INSERT_HEAD(pathlist, new, entry);
269 	if (inserted)
270 		*inserted = new;
271 	return NULL;
272 }
273 
274 void
275 got_pathlist_free(struct got_pathlist_head *pathlist)
276 {
277 	struct got_pathlist_entry *pe;
278 
279 	while ((pe = TAILQ_FIRST(pathlist)) != NULL) {
280 		TAILQ_REMOVE(pathlist, pe, entry);
281 		free(pe);
282 	}
283 }
284 
285 static const struct got_error *
286 make_parent_dirs(const char *abspath)
287 {
288 	const struct got_error *err = NULL;
289 	char *parent;
290 
291 	err = got_path_dirname(&parent, abspath);
292 	if (err)
293 		return err;
294 
295 	if (mkdir(parent, GOT_DEFAULT_DIR_MODE) == -1) {
296 		if (errno == ENOENT) {
297 			err = make_parent_dirs(parent);
298 			if (err)
299 				goto done;
300 			if (mkdir(parent, GOT_DEFAULT_DIR_MODE) == -1) {
301 				err = got_error_from_errno2("mkdir", parent);
302 				goto done;
303 			}
304 		} else
305 			err = got_error_from_errno2("mkdir", parent);
306 	}
307 done:
308 	free(parent);
309 	return err;
310 }
311 
312 const struct got_error *
313 got_path_mkdir(const char *abspath)
314 {
315 	const struct got_error *err = NULL;
316 
317 	if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1) {
318 		if (errno == ENOENT) {
319 			err = make_parent_dirs(abspath);
320 			if (err)
321 				goto done;
322 			if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1)
323 				err = got_error_from_errno2("mkdir", abspath);
324 		} else
325 			err = got_error_from_errno2("mkdir", abspath);
326 	}
327 
328 done:
329 	return err;
330 }
331 
332 int
333 got_path_dir_is_empty(const char *dir)
334 {
335 	DIR *d;
336 	struct dirent *dent;
337 	int empty = 1;
338 
339 	d = opendir(dir);
340 	if (d == NULL)
341 		return 1;
342 
343 	while ((dent = readdir(d)) != NULL) {
344 		if (strcmp(dent->d_name, ".") == 0 ||
345 		    strcmp(dent->d_name, "..") == 0)
346 			continue;
347 
348 		empty = 0;
349 		break;
350 	}
351 
352 	closedir(d);
353 	return empty;
354 }
355 
356 const struct got_error *
357 got_path_dirname(char **parent, const char *path)
358 {
359 	char *p;
360 
361 	p = dirname(path);
362 	if (p == NULL)
363 		return got_error_from_errno2("dirname", path);
364 
365 	if (p[0] == '.' && p[1] == '\0')
366 		return got_error(GOT_ERR_BAD_PATH);
367 
368 	*parent = strdup(p);
369 	if (*parent == NULL)
370 		return got_error_from_errno("strdup");
371 
372 	return NULL;
373 }
374 
375 void
376 got_path_strip_trailing_slashes(char *path)
377 {
378 	int x;
379 
380 	while (path[x = strlen(path) - 1] == '/')
381 		path[x] = '\0';
382 }
383 
384 /* based on findprog() from usr.sbin/which/which.c */
385 const struct got_error *
386 got_path_find_prog(char **filename, const char *prog)
387 {
388 	char *p;
389 	int len;
390 	struct stat sbuf;
391 	char *path, *pathcpy;
392 
393 	*filename = NULL;
394 
395 	path = getenv("PATH");
396 	if (path == NULL)
397 		path = _PATH_DEFPATH;
398 
399 	/* Special case if prog contains '/' */
400 	if (strchr(prog, '/')) {
401 		if ((stat(prog, &sbuf) == 0) && S_ISREG(sbuf.st_mode) &&
402 		    access(prog, X_OK) == 0) {
403 			*filename = strdup(prog);
404 			if (*filename == NULL)
405 				return got_error_from_errno("strdup");
406 		}
407 		return NULL;
408 	}
409 
410 	if ((path = strdup(path)) == NULL)
411 		return got_error_from_errno("strdup");
412 	pathcpy = path;
413 
414 	while ((p = strsep(&pathcpy, ":")) != NULL) {
415 		if (*p == '\0')
416 			p = ".";
417 
418 		len = strlen(p);
419 		while (len > 0 && p[len-1] == '/')
420 			p[--len] = '\0';	/* strip trailing '/' */
421 
422 		if (asprintf(filename, "%s/%s", p, prog) == -1) {
423 			free(path);
424 			return got_error_from_errno("asprintf");
425 		}
426 		if ((stat(*filename, &sbuf) == 0) && S_ISREG(sbuf.st_mode) &&
427 		    access(*filename, X_OK) == 0) {
428 			free(path);
429 			return NULL;
430 		}
431 		free(*filename);
432 		*filename = NULL;
433 		continue;
434 	}
435 	free(path);
436 	return NULL;
437 }
438 
439 const struct got_error *
440 got_path_create_file(const char *path, const char *content)
441 {
442 	const struct got_error *err = NULL;
443 	int fd = -1;
444 
445 	fd = open(path, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW,
446 	    GOT_DEFAULT_FILE_MODE);
447 	if (fd == -1) {
448 		err = got_error_from_errno2("open", path);
449 		goto done;
450 	}
451 
452 	if (content) {
453 		int len = dprintf(fd, "%s\n", content);
454 		if (len != strlen(content) + 1) {
455 			err = got_error_from_errno("dprintf");
456 			goto done;
457 		}
458 	}
459 
460 done:
461 	if (fd != -1 && close(fd) == -1 && err == NULL)
462 		err = got_error_from_errno("close");
463 	return err;
464 }