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(GOT_ERR_BAD_PATH);
116 	if (strncmp(parent_abspath, abspath, len_parent) != 0)
117 		return got_error(GOT_ERR_BAD_PATH);
118 	if (!got_path_is_root_dir(parent_abspath) && abspath[len_parent] != '/')
119 		return got_error(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 	return (path[0] == '/' && path[1] == '\0');
139 }
140 
141 int
142 got_path_is_current_dir(const char *path)
143 {
144 	return (path[0] == '.' && path[1] == '\0');
145 }
146 
147 int
148 got_path_is_child(const char *child, const char *parent, size_t parent_len)
149 {
150 	if (parent_len == 0 || got_path_is_root_dir(parent))
151 		return 1;
152 
153 	if (strncmp(parent, child, parent_len) != 0)
154 		return 0;
155 	if (child[parent_len] != '/')
156 		return 0;
157 
158 	return 1;
159 }
160 
161 int
162 got_path_cmp(const char *path1, const char *path2, size_t len1, size_t len2)
163 {
164 	size_t min_len;
165 	size_t i = 0;
166 
167 	/* Leading directory separators are insignificant. */
168 	while (path1[0] == '/') {
169 		path1++;
170 		len1--;
171 	}
172 	while (path2[0] == '/') {
173 		path2++;
174 		len2--;
175 	}
176 
177 	min_len = MIN(len1, len2);
178 
179 	/* Skip over common prefix. */
180 	while (i < min_len && path1[i] == path2[i])
181 		i++;
182 
183 	/* Are the paths exactly equal (besides path separators)? */
184 	if (len1 == len2 && i >= min_len)
185 		return 0;
186 
187 	/* Skip over redundant trailing path seperators. */
188 	while (path1[i] == '/' && path1[i + 1] == '/')
189 		path1++;
190 	while (path2[i] == '/' && path2[i + 1] == '/')
191 		path2++;
192 
193 	/* Trailing path separators are insignificant. */
194 	if (path1[i] == '/' && path1[i + 1] == '\0' && path2[i] == '\0')
195 		return 0;
196 	if (path2[i] == '/' && path2[i + 1] == '\0' && path1[i] == '\0')
197 		return 0;
198 
199 	/* Order children in subdirectories directly after their parents. */
200 	if (path1[i] == '/' && path2[i] == '\0')
201 		return 1;
202 	if (path2[i] == '/' && path1[i] == '\0')
203 		return -1;
204 	if (path1[i] == '/' && path2[i] != '\0')
205 		return -1;
206 	if (path2[i] == '/' && path1[i] != '\0')
207 		return 1;
208 
209 	/* Next character following the common prefix determines order. */
210 	return (unsigned char)path1[i] < (unsigned char)path2[i] ? -1 : 1;
211 }
212 
213 const struct got_error *
214 got_pathlist_insert(struct got_pathlist_entry **inserted,
215     struct got_pathlist_head *pathlist, const char *path, void *data)
216 {
217 	struct got_pathlist_entry *new, *pe;
218 
219 	if (inserted)
220 		*inserted = NULL;
221 
222 	new = malloc(sizeof(*new));
223 	if (new == NULL)
224 		return got_error_from_errno("malloc");
225 	new->path = path;
226 	new->path_len = strlen(path);
227 	new->data = data;
228 
229 	/*
230 	 * Many callers will provide paths in a somewhat sorted order while
231 	 * constructing a path list from inputs such as tree objects or
232 	 * dirents. Iterating backwards from the tail of the list should
233 	 * be more efficient than traversing through the entire list each
234 	 * time an element is inserted.
235 	 */
236 	pe = TAILQ_LAST(pathlist, got_pathlist_head);
237 	while (pe) {
238 		int cmp = got_path_cmp(pe->path, new->path,
239 		    pe->path_len, new->path_len);
240 		if (cmp == 0) {
241 			free(new); /* duplicate */
242 			return NULL;
243 		} else if (cmp < 0) {
244 			TAILQ_INSERT_AFTER(pathlist, pe, new, entry);
245 			if (inserted)
246 				*inserted = new;
247 			return NULL;
248 		}
249 		pe = TAILQ_PREV(pe, got_pathlist_head, entry);
250 	}
251 
252 	TAILQ_INSERT_HEAD(pathlist, new, entry);
253 	if (inserted)
254 		*inserted = new;
255 	return NULL;
256 }
257 
258 const struct got_error *
259 got_pathlist_append(struct got_pathlist_head *pathlist,
260     const char *path, void *data)
261 {
262 	struct got_pathlist_entry *new;
263 
264 	new = malloc(sizeof(*new));
265 	if (new == NULL)
266 		return got_error_from_errno("malloc");
267 	new->path = path;
268 	new->path_len = strlen(path);
269 	new->data = data;
270 	TAILQ_INSERT_TAIL(pathlist, new, entry);
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 const struct got_error *
376 got_path_basename(char **s, const char *path)
377 {
378 	char *base;
379 
380 	base = basename(path);
381 	if (base == NULL)
382 		return got_error_from_errno2("basename", path);
383 
384 	*s = strdup(base);
385 	if (*s == NULL)
386 		return got_error_from_errno("strdup");
387 
388 	return NULL;
389 }
390 
391 void
392 got_path_strip_trailing_slashes(char *path)
393 {
394 	size_t x;
395 
396 	x = strlen(path);
397 	while (x-- > 0 && path[x] == '/')
398 		path[x] = '\0';
399 }
400 
401 /* based on findprog() from usr.sbin/which/which.c */
402 const struct got_error *
403 got_path_find_prog(char **filename, const char *prog)
404 {
405 	const struct got_error *err = NULL;
406 	char *p;
407 	int len;
408 	struct stat sbuf;
409 	char *path, *pathcpy;
410 
411 	*filename = NULL;
412 
413 	path = getenv("PATH");
414 	if (path == NULL)
415 		path = _PATH_DEFPATH;
416 
417 	/* Special case if prog contains '/' */
418 	if (strchr(prog, '/')) {
419 		if ((stat(prog, &sbuf) == 0) && S_ISREG(sbuf.st_mode) &&
420 		    access(prog, X_OK) == 0) {
421 			*filename = strdup(prog);
422 			if (*filename == NULL)
423 				return got_error_from_errno("strdup");
424 		}
425 		return NULL;
426 	}
427 
428 	if ((path = strdup(path)) == NULL)
429 		return got_error_from_errno("strdup");
430 	pathcpy = path;
431 
432 	while ((p = strsep(&pathcpy, ":")) != NULL) {
433 		if (*p == '\0')
434 			p = ".";
435 
436 		len = strlen(p);
437 		while (len > 0 && p[len-1] == '/')
438 			p[--len] = '\0';	/* strip trailing '/' */
439 
440 		if (asprintf(filename, "%s/%s", p, prog) == -1) {
441 			err = got_error_from_errno("asprintf");
442 			break;
443 		}
444 		if ((stat(*filename, &sbuf) == 0) && S_ISREG(sbuf.st_mode) &&
445 		    access(*filename, X_OK) == 0)
446 			break;
447 		free(*filename);
448 		*filename = NULL;
449 		continue;
450 	}
451 	free(path);
452 	return err;
453 }
454 
455 const struct got_error *
456 got_path_create_file(const char *path, const char *content)
457 {
458 	const struct got_error *err = NULL;
459 	int fd = -1;
460 
461 	fd = open(path, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW,
462 	    GOT_DEFAULT_FILE_MODE);
463 	if (fd == -1) {
464 		err = got_error_from_errno2("open", path);
465 		goto done;
466 	}
467 
468 	if (content) {
469 		int len = dprintf(fd, "%s\n", content);
470 		if (len != strlen(content) + 1) {
471 			err = got_error_from_errno("dprintf");
472 			goto done;
473 		}
474 	}
475 
476 done:
477 	if (fd != -1 && close(fd) == -1 && err == NULL)
478 		err = got_error_from_errno("close");
479 	return err;
480 }