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