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)
163 {
164 	size_t len1 = strlen(path1);
165 	size_t len2 = strlen(path2);
166 	size_t min_len = MIN(len1, len2);
167 	size_t i = 0;
168 
169 	/* Leading directory separators are insignificant. */
170 	while (path1[0] == '/')
171 		path1++;
172 	while (path2[0] == '/')
173 		path2++;
174 
175 	len1 = strlen(path1);
176 	len2 = strlen(path2);
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->data = data;
227 
228 	/*
229 	 * Many callers will provide paths in a somewhat sorted order while
230 	 * constructing a path list from inputs such as tree objects or
231 	 * dirents. Iterating backwards from the tail of the list should
232 	 * be more efficient than traversing through the entire list each
233 	 * time an element is inserted.
234 	 */
235 	pe = TAILQ_LAST(pathlist, got_pathlist_head);
236 	while (pe) {
237 		int cmp = got_path_cmp(pe->path, path);
238 		if (cmp == 0) {
239 			free(new); /* duplicate */
240 			return NULL;
241 		} else if (cmp < 0) {
242 			TAILQ_INSERT_AFTER(pathlist, pe, new, entry);
243 			if (inserted)
244 				*inserted = new;
245 			return NULL;
246 		}
247 		pe = TAILQ_PREV(pe, got_pathlist_head, entry);
248 	}
249 
250 	TAILQ_INSERT_HEAD(pathlist, new, entry);
251 	if (inserted)
252 		*inserted = new;
253 	return NULL;
254 }
255 
256 void
257 got_pathlist_free(struct got_pathlist_head *pathlist)
258 {
259 	struct got_pathlist_entry *pe;
260 
261 	while ((pe = TAILQ_FIRST(pathlist)) != NULL) {
262 		TAILQ_REMOVE(pathlist, pe, entry);
263 		free(pe);
264 	}
265 }
266 
267 static const struct got_error *
268 make_parent_dirs(const char *abspath)
269 {
270 	const struct got_error *err = NULL;
271 	char *parent;
272 
273 	err = got_path_dirname(&parent, abspath);
274 	if (err)
275 		return err;
276 
277 	if (mkdir(parent, GOT_DEFAULT_DIR_MODE) == -1) {
278 		if (errno == ENOENT) {
279 			err = make_parent_dirs(parent);
280 			if (err)
281 				goto done;
282 			if (mkdir(parent, GOT_DEFAULT_DIR_MODE) == -1) {
283 				err = got_error_from_errno2("mkdir", parent);
284 				goto done;
285 			}
286 		} else
287 			err = got_error_from_errno2("mkdir", parent);
288 	}
289 done:
290 	free(parent);
291 	return err;
292 }
293 
294 const struct got_error *
295 got_path_mkdir(const char *abspath)
296 {
297 	const struct got_error *err = NULL;
298 
299 	if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1) {
300 		if (errno == ENOENT) {
301 			err = make_parent_dirs(abspath);
302 			if (err)
303 				goto done;
304 			if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1)
305 				err = got_error_from_errno2("mkdir", abspath);
306 		} else
307 			err = got_error_from_errno2("mkdir", abspath);
308 	}
309 
310 done:
311 	return err;
312 }
313 
314 int
315 got_path_dir_is_empty(const char *dir)
316 {
317 	DIR *d;
318 	struct dirent *dent;
319 	int empty = 1;
320 
321 	d = opendir(dir);
322 	if (d == NULL)
323 		return 1;
324 
325 	while ((dent = readdir(d)) != NULL) {
326 		if (strcmp(dent->d_name, ".") == 0 ||
327 		    strcmp(dent->d_name, "..") == 0)
328 			continue;
329 
330 		empty = 0;
331 		break;
332 	}
333 
334 	closedir(d);
335 	return empty;
336 }
337 
338 const struct got_error *
339 got_path_dirname(char **parent, const char *path)
340 {
341 	char *p;
342 
343 	p = dirname(path);
344 	if (p == NULL)
345 		return got_error_from_errno2("dirname", path);
346 
347 	if (p[0] == '.' && p[1] == '\0')
348 		return got_error(GOT_ERR_BAD_PATH);
349 
350 	*parent = strdup(p);
351 	if (*parent == NULL)
352 		return got_error_from_errno("strdup");
353 
354 	return NULL;
355 }
356 
357 void
358 got_path_strip_trailing_slashes(char *path)
359 {
360 	int x;
361 
362 	while (path[x = strlen(path) - 1] == '/')
363 		path[x] = '\0';
364 }
365 
366 /* based on findprog() from usr.sbin/which/which.c */
367 const struct got_error *
368 got_path_find_prog(char **filename, const char *prog)
369 {
370 	char *p;
371 	int len;
372 	struct stat sbuf;
373 	char *path, *pathcpy;
374 
375 	*filename = NULL;
376 
377 	path = getenv("PATH");
378 	if (path == NULL)
379 		path = _PATH_DEFPATH;
380 
381 	/* Special case if prog contains '/' */
382 	if (strchr(prog, '/')) {
383 		if ((stat(prog, &sbuf) == 0) && S_ISREG(sbuf.st_mode) &&
384 		    access(prog, X_OK) == 0) {
385 			*filename = strdup(prog);
386 			if (*filename == NULL)
387 				return got_error_from_errno("strdup");
388 		}
389 		return NULL;
390 	}
391 
392 	if ((path = strdup(path)) == NULL)
393 		return got_error_from_errno("strdup");
394 	pathcpy = path;
395 
396 	while ((p = strsep(&pathcpy, ":")) != NULL) {
397 		if (*p == '\0')
398 			p = ".";
399 
400 		len = strlen(p);
401 		while (len > 0 && p[len-1] == '/')
402 			p[--len] = '\0';	/* strip trailing '/' */
403 
404 		if (asprintf(filename, "%s/%s", p, prog) == -1) {
405 			free(path);
406 			return got_error_from_errno("asprintf");
407 		}
408 		if ((stat(*filename, &sbuf) == 0) && S_ISREG(sbuf.st_mode) &&
409 		    access(*filename, X_OK) == 0) {
410 			free(path);
411 			return NULL;
412 		}
413 		free(*filename);
414 		*filename = NULL;
415 		continue;
416 	}
417 	free(path);
418 	return NULL;
419 }
420 
421 const struct got_error *
422 got_path_create_file(const char *path, const char *content)
423 {
424 	const struct got_error *err = NULL;
425 	int fd = -1;
426 
427 	fd = open(path, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW,
428 	    GOT_DEFAULT_FILE_MODE);
429 	if (fd == -1) {
430 		err = got_error_from_errno2("open", path);
431 		goto done;
432 	}
433 
434 	if (content) {
435 		int len = dprintf(fd, "%s\n", content);
436 		if (len != strlen(content) + 1) {
437 			err = got_error_from_errno("dprintf");
438 			goto done;
439 		}
440 	}
441 
442 done:
443 	if (fd != -1 && close(fd) == -1 && err == NULL)
444 		err = got_error_from_errno("close");
445 	return err;
446 }