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 /* based on canonpath() from kern_pledge.c */
62 const struct got_error *
63 got_canonpath(const char *input, char *buf, size_t bufsize)
64 {
65 	const char *p;
66 	char *q;
67 
68 	/* can't canon relative paths, don't bother */
69 	if (!got_path_is_absolute(input)) {
70 		if (strlcpy(buf, input, bufsize) >= bufsize)
71 			return got_error(GOT_ERR_NO_SPACE);
72 		return NULL;
73 	}
74 
75 	p = input;
76 	q = buf;
77 	while (*p && (q - buf < bufsize)) {
78 		if (p[0] == '/' && (p[1] == '/' || p[1] == '\0')) {
79 			p += 1;
80 
81 		} else if (p[0] == '/' && p[1] == '.' &&
82 		    (p[2] == '/' || p[2] == '\0')) {
83 			p += 2;
84 
85 		} else if (p[0] == '/' && p[1] == '.' && p[2] == '.' &&
86 		    (p[3] == '/' || p[3] == '\0')) {
87 			p += 3;
88 			if (q != buf)	/* "/../" at start of buf */
89 				while (*--q != '/')
90 					continue;
91 
92 		} else {
93 			*q++ = *p++;
94 		}
95 	}
96 	if ((*p == '\0') && (q - buf < bufsize)) {
97 		*q = 0;
98 		return NULL;
99 	} else
100 		return got_error(GOT_ERR_NO_SPACE);
101 }
102 
103 const struct got_error *
104 got_path_skip_common_ancestor(char **child, const char *parent_abspath,
105     const char *abspath)
106 {
107 	const struct got_error *err = NULL;
108 	size_t len_parent, len, bufsize;
109 
110 	*child = NULL;
111 
112 	len_parent = strlen(parent_abspath);
113 	len = strlen(abspath);
114 	if (len_parent >= len)
115 		return got_error_path(abspath, GOT_ERR_BAD_PATH);
116 	if (strncmp(parent_abspath, abspath, len_parent) != 0)
117 		return got_error_path(abspath, GOT_ERR_BAD_PATH);
118 	if (!got_path_is_root_dir(parent_abspath) && abspath[len_parent] != '/')
119 		return got_error_path(abspath, GOT_ERR_BAD_PATH);
120 	while (abspath[len_parent] == '/')
121 		abspath++;
122 	bufsize = len - len_parent + 1;
123 	*child = malloc(bufsize);
124 	if (*child == NULL)
125 		return got_error_from_errno("malloc");
126 	if (strlcpy(*child, abspath + len_parent, bufsize) >= bufsize) {
127 		err = got_error_from_errno("strlcpy");
128 		free(*child);
129 		*child = NULL;
130 		return err;
131 	}
132 	return NULL;
133 }
134 
135 int
136 got_path_is_root_dir(const char *path)
137 {
138 	while (*path == '/')
139 		path++;
140 	return (*path == '\0');
141 }
142 
143 int
144 got_path_is_current_dir(const char *path)
145 {
146 	return (path[0] == '.' && path[1] == '\0');
147 }
148 
149 int
150 got_path_is_child(const char *child, const char *parent, size_t parent_len)
151 {
152 	if (parent_len == 0 || got_path_is_root_dir(parent))
153 		return 1;
154 
155 	if (strncmp(parent, child, parent_len) != 0)
156 		return 0;
157 	if (child[parent_len] != '/')
158 		return 0;
159 
160 	return 1;
161 }
162 
163 int
164 got_path_cmp(const char *path1, const char *path2, size_t len1, size_t len2)
165 {
166 	size_t min_len;
167 	size_t i = 0;
168 
169 	/* Leading directory separators are insignificant. */
170 	while (path1[0] == '/') {
171 		path1++;
172 		len1--;
173 	}
174 	while (path2[0] == '/') {
175 		path2++;
176 		len2--;
177 	}
178 
179 	min_len = MIN(len1, len2);
180 
181 	/* Skip over common prefix. */
182 	while (i < min_len && path1[i] == path2[i])
183 		i++;
184 
185 	/* Are the paths exactly equal (besides path separators)? */
186 	if (len1 == len2 && i >= min_len)
187 		return 0;
188 
189 	/* Skip over redundant trailing path seperators. */
190 	while (path1[i] == '/' && path1[i + 1] == '/')
191 		path1++;
192 	while (path2[i] == '/' && path2[i + 1] == '/')
193 		path2++;
194 
195 	/* Trailing path separators are insignificant. */
196 	if (path1[i] == '/' && path1[i + 1] == '\0' && path2[i] == '\0')
197 		return 0;
198 	if (path2[i] == '/' && path2[i + 1] == '\0' && path1[i] == '\0')
199 		return 0;
200 
201 	/* Order children in subdirectories directly after their parents. */
202 	if (path1[i] == '/' && path2[i] == '\0')
203 		return 1;
204 	if (path2[i] == '/' && path1[i] == '\0')
205 		return -1;
206 	if (path1[i] == '/' && path2[i] != '\0')
207 		return -1;
208 	if (path2[i] == '/' && path1[i] != '\0')
209 		return 1;
210 
211 	/* Next character following the common prefix determines order. */
212 	return (unsigned char)path1[i] < (unsigned char)path2[i] ? -1 : 1;
213 }
214 
215 const struct got_error *
216 got_pathlist_insert(struct got_pathlist_entry **inserted,
217     struct got_pathlist_head *pathlist, const char *path, void *data)
218 {
219 	struct got_pathlist_entry *new, *pe;
220 
221 	if (inserted)
222 		*inserted = NULL;
223 
224 	new = malloc(sizeof(*new));
225 	if (new == NULL)
226 		return got_error_from_errno("malloc");
227 	new->path = path;
228 	new->path_len = strlen(path);
229 	new->data = data;
230 
231 	/*
232 	 * Many callers will provide paths in a somewhat sorted order while
233 	 * constructing a path list from inputs such as tree objects or
234 	 * dirents. Iterating backwards from the tail of the list should
235 	 * be more efficient than traversing through the entire list each
236 	 * time an element is inserted.
237 	 */
238 	pe = TAILQ_LAST(pathlist, got_pathlist_head);
239 	while (pe) {
240 		int cmp = got_path_cmp(pe->path, new->path,
241 		    pe->path_len, new->path_len);
242 		if (cmp == 0) {
243 			free(new); /* duplicate */
244 			return NULL;
245 		} else if (cmp < 0) {
246 			TAILQ_INSERT_AFTER(pathlist, pe, new, entry);
247 			if (inserted)
248 				*inserted = new;
249 			return NULL;
250 		}
251 		pe = TAILQ_PREV(pe, got_pathlist_head, entry);
252 	}
253 
254 	TAILQ_INSERT_HEAD(pathlist, new, entry);
255 	if (inserted)
256 		*inserted = new;
257 	return NULL;
258 }
259 
260 const struct got_error *
261 got_pathlist_append(struct got_pathlist_head *pathlist,
262     const char *path, void *data)
263 {
264 	struct got_pathlist_entry *new;
265 
266 	new = malloc(sizeof(*new));
267 	if (new == NULL)
268 		return got_error_from_errno("malloc");
269 	new->path = path;
270 	new->path_len = strlen(path);
271 	new->data = data;
272 	TAILQ_INSERT_TAIL(pathlist, new, entry);
273 	return NULL;
274 }
275 
276 void
277 got_pathlist_free(struct got_pathlist_head *pathlist)
278 {
279 	struct got_pathlist_entry *pe;
280 
281 	while ((pe = TAILQ_FIRST(pathlist)) != NULL) {
282 		TAILQ_REMOVE(pathlist, pe, entry);
283 		free(pe);
284 	}
285 }
286 
287 static const struct got_error *
288 make_parent_dirs(const char *abspath)
289 {
290 	const struct got_error *err = NULL;
291 	char *parent;
292 
293 	err = got_path_dirname(&parent, abspath);
294 	if (err)
295 		return err;
296 
297 	if (mkdir(parent, GOT_DEFAULT_DIR_MODE) == -1) {
298 		if (errno == ENOENT) {
299 			err = make_parent_dirs(parent);
300 			if (err)
301 				goto done;
302 			if (mkdir(parent, GOT_DEFAULT_DIR_MODE) == -1) {
303 				err = got_error_from_errno2("mkdir", parent);
304 				goto done;
305 			}
306 		} else
307 			err = got_error_from_errno2("mkdir", parent);
308 	}
309 done:
310 	free(parent);
311 	return err;
312 }
313 
314 const struct got_error *
315 got_path_mkdir(const char *abspath)
316 {
317 	const struct got_error *err = NULL;
318 
319 	if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1) {
320 		if (errno == ENOENT) {
321 			err = make_parent_dirs(abspath);
322 			if (err)
323 				goto done;
324 			if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1)
325 				err = got_error_from_errno2("mkdir", abspath);
326 		} else
327 			err = got_error_from_errno2("mkdir", abspath);
328 	}
329 
330 done:
331 	return err;
332 }
333 
334 int
335 got_path_dir_is_empty(const char *dir)
336 {
337 	DIR *d;
338 	struct dirent *dent;
339 	int empty = 1;
340 
341 	d = opendir(dir);
342 	if (d == NULL)
343 		return 1;
344 
345 	while ((dent = readdir(d)) != NULL) {
346 		if (strcmp(dent->d_name, ".") == 0 ||
347 		    strcmp(dent->d_name, "..") == 0)
348 			continue;
349 
350 		empty = 0;
351 		break;
352 	}
353 
354 	closedir(d);
355 	return empty;
356 }
357 
358 const struct got_error *
359 got_path_dirname(char **parent, const char *path)
360 {
361 	char *p;
362 
363 	p = dirname(path);
364 	if (p == NULL)
365 		return got_error_from_errno2("dirname", path);
366 
367 	if (p[0] == '.' && p[1] == '\0')
368 		return got_error_path(path, GOT_ERR_BAD_PATH);
369 
370 	*parent = strdup(p);
371 	if (*parent == NULL)
372 		return got_error_from_errno("strdup");
373 
374 	return NULL;
375 }
376 
377 const struct got_error *
378 got_path_dirent_type(int *type, const char *path_parent, struct dirent *dent)
379 {
380 	const struct got_error *err = NULL;
381 	char *path_child;
382 	struct stat sb;
383 
384 	if (dent->d_type != DT_UNKNOWN) {
385 		*type = dent->d_type;
386 		return NULL;
387 	}
388 
389 	*type = DT_UNKNOWN;
390 
391 	/*
392 	 * This is a fallback to accommodate filesystems which do not
393 	 * provide directory entry type information. DT_UNKNOWN directory
394 	 * entries occur on NFS mounts without "readdir plus" RPC.
395 	 */
396 
397 	if (asprintf(&path_child, "%s/%s", path_parent, dent->d_name) == -1)
398 		return got_error_from_errno("asprintf");
399 
400 	if (lstat(path_child, &sb) == -1) {
401 		err = got_error_from_errno2("lstat", path_child);
402 		goto done;
403 	}
404 
405 	if (S_ISFIFO(sb.st_mode))
406 		*type = DT_FIFO;
407 	else if (S_ISCHR(sb.st_mode))
408 		*type = DT_CHR;
409 	else if (S_ISDIR(sb.st_mode))
410 		*type = DT_DIR;
411 	else if (S_ISBLK(sb.st_mode))
412 		*type = DT_BLK;
413 	else if (S_ISLNK(sb.st_mode))
414 		*type = DT_LNK;
415 	else if (S_ISREG(sb.st_mode))
416 		*type = DT_REG;
417 	else if (S_ISSOCK(sb.st_mode))
418 		*type = DT_SOCK;
419 done:
420 	free(path_child);
421 	return err;
422 }
423 
424 const struct got_error *
425 got_path_basename(char **s, const char *path)
426 {
427 	char *base;
428 
429 	base = basename(path);
430 	if (base == NULL)
431 		return got_error_from_errno2("basename", path);
432 
433 	*s = strdup(base);
434 	if (*s == NULL)
435 		return got_error_from_errno("strdup");
436 
437 	return NULL;
438 }
439 
440 void
441 got_path_strip_trailing_slashes(char *path)
442 {
443 	size_t x;
444 
445 	x = strlen(path);
446 	while (x-- > 0 && path[x] == '/')
447 		path[x] = '\0';
448 }
449 
450 /* based on findprog() from usr.sbin/which/which.c */
451 const struct got_error *
452 got_path_find_prog(char **filename, const char *prog)
453 {
454 	const struct got_error *err = NULL;
455 	char *p;
456 	int len;
457 	struct stat sbuf;
458 	char *path, *pathcpy;
459 
460 	*filename = NULL;
461 
462 	path = getenv("PATH");
463 	if (path == NULL)
464 		path = _PATH_DEFPATH;
465 
466 	/* Special case if prog contains '/' */
467 	if (strchr(prog, '/')) {
468 		if ((stat(prog, &sbuf) == 0) && S_ISREG(sbuf.st_mode) &&
469 		    access(prog, X_OK) == 0) {
470 			*filename = strdup(prog);
471 			if (*filename == NULL)
472 				return got_error_from_errno("strdup");
473 		}
474 		return NULL;
475 	}
476 
477 	if ((path = strdup(path)) == NULL)
478 		return got_error_from_errno("strdup");
479 	pathcpy = path;
480 
481 	while ((p = strsep(&pathcpy, ":")) != NULL) {
482 		if (*p == '\0')
483 			p = ".";
484 
485 		len = strlen(p);
486 		while (len > 0 && p[len-1] == '/')
487 			p[--len] = '\0';	/* strip trailing '/' */
488 
489 		if (asprintf(filename, "%s/%s", p, prog) == -1) {
490 			err = got_error_from_errno("asprintf");
491 			break;
492 		}
493 		if ((stat(*filename, &sbuf) == 0) && S_ISREG(sbuf.st_mode) &&
494 		    access(*filename, X_OK) == 0)
495 			break;
496 		free(*filename);
497 		*filename = NULL;
498 		continue;
499 	}
500 	free(path);
501 	return err;
502 }
503 
504 const struct got_error *
505 got_path_create_file(const char *path, const char *content)
506 {
507 	const struct got_error *err = NULL;
508 	int fd = -1;
509 
510 	fd = open(path, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW,
511 	    GOT_DEFAULT_FILE_MODE);
512 	if (fd == -1) {
513 		err = got_error_from_errno2("open", path);
514 		goto done;
515 	}
516 
517 	if (content) {
518 		int len = dprintf(fd, "%s\n", content);
519 		if (len != strlen(content) + 1) {
520 			err = got_error_from_errno("dprintf");
521 			goto done;
522 		}
523 	}
524 
525 done:
526 	if (fd != -1 && close(fd) == -1 && err == NULL)
527 		err = got_error_from_errno("close");
528 	return err;
529 }