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Date:: Fri Jul 1 21:13:24 2022 UTC
Message:: build with -Wwrite-strings Throwing this into the mix for a while, we can always get rid of it again if it becomes annoying. No objections from stsp@
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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/stat.h>
20 
21 #include <errno.h>
22 #include <fcntl.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_compat.h"
33 
34 #include "got_error.h"
35 #include "got_path.h"
36 
37 #ifndef MIN
38 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
39 #endif
40 
41 int
42 got_path_is_absolute(const char *path)
43 {
44 	return path[0] == '/';
45 }
46 
47 /* based on canonpath() from kern_pledge.c */
48 const struct got_error *
49 got_canonpath(const char *input, char *buf, size_t bufsize)
50 {
51 	const char *p;
52 	char *q;
53 
54 	/* can't canon relative paths, don't bother */
55 	if (!got_path_is_absolute(input)) {
56 		if (strlcpy(buf, input, bufsize) >= bufsize)
57 			return got_error(GOT_ERR_NO_SPACE);
58 		return NULL;
59 	}
60 
61 	p = input;
62 	q = buf;
63 	while (*p && (q - buf < bufsize)) {
64 		if (p[0] == '/' && (p[1] == '/' || p[1] == '\0')) {
65 			p += 1;
66 
67 		} else if (p[0] == '/' && p[1] == '.' &&
68 		    (p[2] == '/' || p[2] == '\0')) {
69 			p += 2;
70 
71 		} else if (p[0] == '/' && p[1] == '.' && p[2] == '.' &&
72 		    (p[3] == '/' || p[3] == '\0')) {
73 			p += 3;
74 			if (q != buf)	/* "/../" at start of buf */
75 				while (*--q != '/')
76 					continue;
77 
78 		} else {
79 			*q++ = *p++;
80 		}
81 	}
82 	if ((*p == '\0') && (q - buf < bufsize)) {
83 		*q = 0;
84 		return NULL;
85 	} else
86 		return got_error(GOT_ERR_NO_SPACE);
87 }
88 
89 const struct got_error *
90 got_path_skip_common_ancestor(char **child, const char *parent_abspath,
91     const char *abspath)
92 {
93 	const struct got_error *err = NULL;
94 	size_t len_parent, len, bufsize;
95 
96 	*child = NULL;
97 
98 	len_parent = strlen(parent_abspath);
99 	len = strlen(abspath);
100 	if (len_parent >= len)
101 		return got_error_path(abspath, GOT_ERR_BAD_PATH);
102 	if (strncmp(parent_abspath, abspath, len_parent) != 0)
103 		return got_error_path(abspath, GOT_ERR_BAD_PATH);
104 	if (!got_path_is_root_dir(parent_abspath) && abspath[len_parent] != '/')
105 		return got_error_path(abspath, GOT_ERR_BAD_PATH);
106 	while (abspath[len_parent] == '/')
107 		abspath++;
108 	bufsize = len - len_parent + 1;
109 	*child = malloc(bufsize);
110 	if (*child == NULL)
111 		return got_error_from_errno("malloc");
112 	if (strlcpy(*child, abspath + len_parent, bufsize) >= bufsize) {
113 		err = got_error_from_errno("strlcpy");
114 		free(*child);
115 		*child = NULL;
116 		return err;
117 	}
118 	return NULL;
119 }
120 
121 const struct got_error *
122 got_path_strip(char **out, const char *path, int n)
123 {
124 	const char *p, *c;
125 
126 	p = path;
127 	*out = NULL;
128 
129 	while (n > 0 && (c = strchr(p, '/')) != NULL) {
130 		p = c + 1;
131 		n--;
132 	}
133 
134 	if (n > 0)
135 		return got_error_fmt(GOT_ERR_BAD_PATH,
136 		    "can't strip %d path-components from %s", n, path);
137 
138 	if ((*out = strdup(p)) == NULL)
139 		return got_error_from_errno("strdup");
140 	return NULL;
141 }
142 
143 int
144 got_path_is_root_dir(const char *path)
145 {
146 	while (*path == '/')
147 		path++;
148 	return (*path == '\0');
149 }
150 
151 int
152 got_path_is_child(const char *child, const char *parent, size_t parent_len)
153 {
154 	if (parent_len == 0 || got_path_is_root_dir(parent))
155 		return 1;
156 
157 	if (strncmp(parent, child, parent_len) != 0)
158 		return 0;
159 	if (child[parent_len] != '/')
160 		return 0;
161 
162 	return 1;
163 }
164 
165 int
166 got_path_cmp(const char *path1, const char *path2, size_t len1, size_t len2)
167 {
168 	size_t min_len;
169 	size_t i = 0;
170 
171 	/* Leading directory separators are insignificant. */
172 	while (path1[0] == '/') {
173 		path1++;
174 		len1--;
175 	}
176 	while (path2[0] == '/') {
177 		path2++;
178 		len2--;
179 	}
180 
181 	min_len = MIN(len1, len2);
182 
183 	/* Skip over common prefix. */
184 	while (i < min_len && path1[i] == path2[i])
185 		i++;
186 
187 	/* Are the paths exactly equal (besides path separators)? */
188 	if (len1 == len2 && i >= min_len)
189 		return 0;
190 
191 	/* Skip over redundant trailing path seperators. */
192 	while (path1[i] == '/' && path1[i + 1] == '/')
193 		path1++;
194 	while (path2[i] == '/' && path2[i + 1] == '/')
195 		path2++;
196 
197 	/* Trailing path separators are insignificant. */
198 	if (path1[i] == '/' && path1[i + 1] == '\0' && path2[i] == '\0')
199 		return 0;
200 	if (path2[i] == '/' && path2[i + 1] == '\0' && path1[i] == '\0')
201 		return 0;
202 
203 	/* Order children in subdirectories directly after their parents. */
204 	if (path1[i] == '/' && path2[i] == '\0')
205 		return 1;
206 	if (path2[i] == '/' && path1[i] == '\0')
207 		return -1;
208 	if (path1[i] == '/' && path2[i] != '\0')
209 		return -1;
210 	if (path2[i] == '/' && path1[i] != '\0')
211 		return 1;
212 
213 	/* Next character following the common prefix determines order. */
214 	return (unsigned char)path1[i] < (unsigned char)path2[i] ? -1 : 1;
215 }
216 
217 const struct got_error *
218 got_pathlist_insert(struct got_pathlist_entry **inserted,
219     struct got_pathlist_head *pathlist, const char *path, void *data)
220 {
221 	struct got_pathlist_entry *new, *pe;
222 	size_t path_len = strlen(path);
223 
224 	if (inserted)
225 		*inserted = NULL;
226 
227 	/*
228 	 * Many callers will provide paths in a somewhat sorted order while
229 	 * constructing a path list from inputs such as tree objects or
230 	 * dirents. Iterating backwards from the tail of the list should
231 	 * be more efficient than traversing through the entire list each
232 	 * time an element is inserted.
233 	 */
234 	pe = TAILQ_LAST(pathlist, got_pathlist_head);
235 	while (pe) {
236 		int cmp = got_path_cmp(pe->path, path, pe->path_len, path_len);
237 		if (cmp == 0)
238 			return NULL;  /* duplicate */
239 		else if (cmp < 0)
240 			break;
241 		pe = TAILQ_PREV(pe, got_pathlist_head, entry);
242 	}
243 
244 	new = malloc(sizeof(*new));
245 	if (new == NULL)
246 		return got_error_from_errno("malloc");
247 	new->path = path;
248 	new->path_len = path_len;
249 	new->data = data;
250 	if (pe)
251 		TAILQ_INSERT_AFTER(pathlist, pe, new, entry);
252 	else
253 		TAILQ_INSERT_HEAD(pathlist, new, entry);
254 	if (inserted)
255 		*inserted = new;
256 	return NULL;
257 }
258 
259 const struct got_error *
260 got_pathlist_append(struct got_pathlist_head *pathlist,
261     const char *path, void *data)
262 {
263 	struct got_pathlist_entry *new;
264 
265 	new = malloc(sizeof(*new));
266 	if (new == NULL)
267 		return got_error_from_errno("malloc");
268 	new->path = path;
269 	new->path_len = strlen(path);
270 	new->data = data;
271 	TAILQ_INSERT_TAIL(pathlist, new, entry);
272 	return NULL;
273 }
274 
275 void
276 got_pathlist_free(struct got_pathlist_head *pathlist)
277 {
278 	struct got_pathlist_entry *pe;
279 
280 	while ((pe = TAILQ_FIRST(pathlist)) != NULL) {
281 		TAILQ_REMOVE(pathlist, pe, entry);
282 		free(pe);
283 	}
284 }
285 
286 static const struct got_error *
287 make_parent_dirs(const char *abspath)
288 {
289 	const struct got_error *err = NULL;
290 	char *parent;
291 
292 	err = got_path_dirname(&parent, abspath);
293 	if (err)
294 		return err;
295 
296 	if (mkdir(parent, GOT_DEFAULT_DIR_MODE) == -1) {
297 		if (errno == ENOENT) {
298 			err = make_parent_dirs(parent);
299 			if (err)
300 				goto done;
301 			if (mkdir(parent, GOT_DEFAULT_DIR_MODE) == -1) {
302 				err = got_error_from_errno2("mkdir", parent);
303 				goto done;
304 			}
305 		} else
306 			err = got_error_from_errno2("mkdir", parent);
307 	}
308 done:
309 	free(parent);
310 	return err;
311 }
312 
313 const struct got_error *
314 got_path_mkdir(const char *abspath)
315 {
316 	const struct got_error *err = NULL;
317 
318 	if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1) {
319 		if (errno == ENOENT) {
320 			err = make_parent_dirs(abspath);
321 			if (err)
322 				goto done;
323 			if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1)
324 				err = got_error_from_errno2("mkdir", abspath);
325 		} else
326 			err = got_error_from_errno2("mkdir", abspath);
327 	}
328 
329 done:
330 	return err;
331 }
332 
333 int
334 got_path_dir_is_empty(const char *dir)
335 {
336 	DIR *d;
337 	struct dirent *dent;
338 	int empty = 1;
339 
340 	d = opendir(dir);
341 	if (d == NULL)
342 		return 1;
343 
344 	while ((dent = readdir(d)) != NULL) {
345 		if (strcmp(dent->d_name, ".") == 0 ||
346 		    strcmp(dent->d_name, "..") == 0)
347 			continue;
348 
349 		empty = 0;
350 		break;
351 	}
352 
353 	closedir(d);
354 	return empty;
355 }
356 
357 const struct got_error *
358 got_path_dirname(char **parent, const char *path)
359 {
360 	char buf[PATH_MAX];
361 	char *p;
362 
363 	if (strlcpy(buf, path, sizeof(buf)) >= sizeof(buf))
364 		return got_error(GOT_ERR_NO_SPACE);
365 
366 	p = dirname(buf);
367 	if (p == NULL)
368 		return got_error_from_errno2("dirname", path);
369 
370 	if (p[0] == '.' && p[1] == '\0')
371 		return got_error_path(path, GOT_ERR_BAD_PATH);
372 
373 	*parent = strdup(p);
374 	if (*parent == NULL)
375 		return got_error_from_errno("strdup");
376 
377 	return NULL;
378 }
379 
380 const struct got_error *
381 got_path_dirent_type(int *type, const char *path_parent, struct dirent *dent)
382 {
383 	const struct got_error *err = NULL;
384 	char *path_child;
385 	struct stat sb;
386 
387 	if (dent->d_type != DT_UNKNOWN) {
388 		*type = dent->d_type;
389 		return NULL;
390 	}
391 
392 	*type = DT_UNKNOWN;
393 
394 	/*
395 	 * This is a fallback to accommodate filesystems which do not
396 	 * provide directory entry type information. DT_UNKNOWN directory
397 	 * entries occur on NFS mounts without "readdir plus" RPC.
398 	 */
399 
400 	if (asprintf(&path_child, "%s/%s", path_parent, dent->d_name) == -1)
401 		return got_error_from_errno("asprintf");
402 
403 	if (lstat(path_child, &sb) == -1) {
404 		err = got_error_from_errno2("lstat", path_child);
405 		goto done;
406 	}
407 
408 	if (S_ISFIFO(sb.st_mode))
409 		*type = DT_FIFO;
410 	else if (S_ISCHR(sb.st_mode))
411 		*type = DT_CHR;
412 	else if (S_ISDIR(sb.st_mode))
413 		*type = DT_DIR;
414 	else if (S_ISBLK(sb.st_mode))
415 		*type = DT_BLK;
416 	else if (S_ISLNK(sb.st_mode))
417 		*type = DT_LNK;
418 	else if (S_ISREG(sb.st_mode))
419 		*type = DT_REG;
420 	else if (S_ISSOCK(sb.st_mode))
421 		*type = DT_SOCK;
422 done:
423 	free(path_child);
424 	return err;
425 }
426 
427 const struct got_error *
428 got_path_basename(char **s, const char *path)
429 {
430 	char buf[PATH_MAX];
431 	char *base;
432 
433 	if (strlcpy(buf, path, sizeof(buf)) >= sizeof(buf))
434 		return got_error(GOT_ERR_NO_SPACE);
435 
436 	base = basename(buf);
437 	if (base == NULL)
438 		return got_error_from_errno2("basename", path);
439 
440 	*s = strdup(base);
441 	if (*s == NULL)
442 		return got_error_from_errno("strdup");
443 
444 	return NULL;
445 }
446 
447 void
448 got_path_strip_trailing_slashes(char *path)
449 {
450 	size_t x;
451 
452 	x = strlen(path);
453 	while (x-- > 0 && path[x] == '/')
454 		path[x] = '\0';
455 }
456 
457 /* based on findprog() from usr.bin/which/which.c */
458 const struct got_error *
459 got_path_find_prog(char **filename, const char *prog)
460 {
461 	const struct got_error *err = NULL;
462 	const char *path;
463 	char *p;
464 	int len;
465 	struct stat sbuf;
466 	char *pathcpy, *dup = NULL;
467 
468 	*filename = NULL;
469 
470 	path = getenv("PATH");
471 	if (path == NULL)
472 		path = _PATH_DEFPATH;
473 
474 	/* Special case if prog contains '/' */
475 	if (strchr(prog, '/')) {
476 		if ((stat(prog, &sbuf) == 0) && S_ISREG(sbuf.st_mode) &&
477 		    access(prog, X_OK) == 0) {
478 			*filename = strdup(prog);
479 			if (*filename == NULL)
480 				return got_error_from_errno("strdup");
481 		}
482 		return NULL;
483 	}
484 
485 	if ((dup = strdup(path)) == NULL)
486 		return got_error_from_errno("strdup");
487 	pathcpy = dup;
488 
489 	while ((p = strsep(&pathcpy, ":")) != NULL) {
490 		const char *d;
491 
492 		len = strlen(p);
493 		while (len > 0 && p[len-1] == '/')
494 			p[--len] = '\0';	/* strip trailing '/' */
495 
496 		d = p;
497 		if (*d == '\0')
498 			d = ".";
499 
500 		if (asprintf(filename, "%s/%s", d, prog) == -1) {
501 			err = got_error_from_errno("asprintf");
502 			break;
503 		}
504 		if ((stat(*filename, &sbuf) == 0) && S_ISREG(sbuf.st_mode) &&
505 		    access(*filename, X_OK) == 0)
506 			break;
507 		free(*filename);
508 		*filename = NULL;
509 		continue;
510 	}
511 	free(dup);
512 	return err;
513 }
514 
515 const struct got_error *
516 got_path_create_file(const char *path, const char *content)
517 {
518 	const struct got_error *err = NULL;
519 	int fd = -1;
520 
521 	fd = open(path, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW | O_CLOEXEC,
522 	    GOT_DEFAULT_FILE_MODE);
523 	if (fd == -1) {
524 		err = got_error_from_errno2("open", path);
525 		goto done;
526 	}
527 
528 	if (content) {
529 		int len = dprintf(fd, "%s\n", content);
530 		if (len != strlen(content) + 1) {
531 			err = got_error_from_errno("dprintf");
532 			goto done;
533 		}
534 	}
535 
536 done:
537 	if (fd != -1 && close(fd) == -1 && err == NULL)
538 		err = got_error_from_errno("close");
539 	return err;
540 }