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Date:: Tue Jan 10 10:47:08 2023 UTC
Message:: got: minor refactor of got_pathlist_free() API Accept flag parameter to optionally specify which pointers to free. This saves callers looping through the list to free pointers. ok + fix 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/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 /* based on canonpath() from kern_pledge.c */
47 const struct got_error *
48 got_canonpath(const char *input, char *buf, size_t bufsize)
49 {
50 	const char *p;
51 	char *q;
52 
53 	/* can't canon relative paths, don't bother */
54 	if (!got_path_is_absolute(input)) {
55 		if (strlcpy(buf, input, bufsize) >= bufsize)
56 			return got_error(GOT_ERR_NO_SPACE);
57 		return NULL;
58 	}
59 
60 	p = input;
61 	q = buf;
62 	while (*p && (q - buf < bufsize)) {
63 		if (p[0] == '/' && (p[1] == '/' || p[1] == '\0')) {
64 			p += 1;
65 
66 		} else if (p[0] == '/' && p[1] == '.' &&
67 		    (p[2] == '/' || p[2] == '\0')) {
68 			p += 2;
69 
70 		} else if (p[0] == '/' && p[1] == '.' && p[2] == '.' &&
71 		    (p[3] == '/' || p[3] == '\0')) {
72 			p += 3;
73 			if (q != buf)	/* "/../" at start of buf */
74 				while (*--q != '/')
75 					continue;
76 
77 		} else {
78 			*q++ = *p++;
79 		}
80 	}
81 	if ((*p == '\0') && (q - buf < bufsize)) {
82 		*q = 0;
83 		return NULL;
84 	} else
85 		return got_error(GOT_ERR_NO_SPACE);
86 }
87 
88 const struct got_error *
89 got_path_skip_common_ancestor(char **child, const char *parent_abspath,
90     const char *abspath)
91 {
92 	const struct got_error *err = NULL;
93 	size_t len_parent, len, bufsize;
94 
95 	*child = NULL;
96 
97 	len_parent = strlen(parent_abspath);
98 	len = strlen(abspath);
99 	if (len_parent >= len)
100 		return got_error_path(abspath, GOT_ERR_BAD_PATH);
101 	if (strncmp(parent_abspath, abspath, len_parent) != 0)
102 		return got_error_path(abspath, GOT_ERR_BAD_PATH);
103 	if (!got_path_is_root_dir(parent_abspath) && abspath[len_parent] != '/')
104 		return got_error_path(abspath, GOT_ERR_BAD_PATH);
105 	while (abspath[len_parent] == '/')
106 		abspath++;
107 	bufsize = len - len_parent + 1;
108 	*child = malloc(bufsize);
109 	if (*child == NULL)
110 		return got_error_from_errno("malloc");
111 	if (strlcpy(*child, abspath + len_parent, bufsize) >= bufsize) {
112 		err = got_error_from_errno("strlcpy");
113 		free(*child);
114 		*child = NULL;
115 		return err;
116 	}
117 	return NULL;
118 }
119 
120 const struct got_error *
121 got_path_strip(char **out, const char *path, int n)
122 {
123 	const char *p, *c;
124 
125 	p = path;
126 	*out = NULL;
127 
128 	while (n > 0 && (c = strchr(p, '/')) != NULL) {
129 		p = c + 1;
130 		n--;
131 	}
132 
133 	if (n > 0)
134 		return got_error_fmt(GOT_ERR_BAD_PATH,
135 		    "can't strip %d path-components from %s", n, path);
136 
137 	if ((*out = strdup(p)) == NULL)
138 		return got_error_from_errno("strdup");
139 	return NULL;
140 }
141 
142 int
143 got_path_is_root_dir(const char *path)
144 {
145 	while (*path == '/')
146 		path++;
147 	return (*path == '\0');
148 }
149 
150 int
151 got_path_is_child(const char *child, const char *parent, size_t parent_len)
152 {
153 	if (parent_len == 0 || got_path_is_root_dir(parent))
154 		return 1;
155 
156 	if (strncmp(parent, child, parent_len) != 0)
157 		return 0;
158 	if (child[parent_len] != '/')
159 		return 0;
160 
161 	return 1;
162 }
163 
164 int
165 got_path_cmp(const char *path1, const char *path2, size_t len1, size_t len2)
166 {
167 	size_t min_len;
168 	size_t i = 0;
169 
170 	/* Leading directory separators are insignificant. */
171 	while (path1[0] == '/') {
172 		path1++;
173 		len1--;
174 	}
175 	while (path2[0] == '/') {
176 		path2++;
177 		len2--;
178 	}
179 
180 	min_len = MIN(len1, len2);
181 
182 	/* Skip over common prefix. */
183 	while (i < min_len && path1[i] == path2[i])
184 		i++;
185 
186 	/* Are the paths exactly equal (besides path separators)? */
187 	if (len1 == len2 && i >= min_len)
188 		return 0;
189 
190 	/* Skip over redundant trailing path seperators. */
191 	while (path1[i] == '/' && path1[i + 1] == '/')
192 		path1++;
193 	while (path2[i] == '/' && path2[i + 1] == '/')
194 		path2++;
195 
196 	/* Trailing path separators are insignificant. */
197 	if (path1[i] == '/' && path1[i + 1] == '\0' && path2[i] == '\0')
198 		return 0;
199 	if (path2[i] == '/' && path2[i + 1] == '\0' && path1[i] == '\0')
200 		return 0;
201 
202 	/* Order children in subdirectories directly after their parents. */
203 	if (path1[i] == '/' && path2[i] == '\0')
204 		return 1;
205 	if (path2[i] == '/' && path1[i] == '\0')
206 		return -1;
207 	if (path1[i] == '/' && path2[i] != '\0')
208 		return -1;
209 	if (path2[i] == '/' && path1[i] != '\0')
210 		return 1;
211 
212 	/* Next character following the common prefix determines order. */
213 	return (unsigned char)path1[i] < (unsigned char)path2[i] ? -1 : 1;
214 }
215 
216 const struct got_error *
217 got_pathlist_insert(struct got_pathlist_entry **inserted,
218     struct got_pathlist_head *pathlist, const char *path, void *data)
219 {
220 	struct got_pathlist_entry *new, *pe;
221 	size_t path_len = strlen(path);
222 
223 	if (inserted)
224 		*inserted = NULL;
225 
226 	/*
227 	 * Many callers will provide paths in a somewhat sorted order while
228 	 * constructing a path list from inputs such as tree objects or
229 	 * dirents. Iterating backwards from the tail of the list should
230 	 * be more efficient than traversing through the entire list each
231 	 * time an element is inserted.
232 	 */
233 	pe = TAILQ_LAST(pathlist, got_pathlist_head);
234 	while (pe) {
235 		int cmp = got_path_cmp(pe->path, path, pe->path_len, path_len);
236 		if (cmp == 0)
237 			return NULL;  /* duplicate */
238 		else if (cmp < 0)
239 			break;
240 		pe = TAILQ_PREV(pe, got_pathlist_head, entry);
241 	}
242 
243 	new = malloc(sizeof(*new));
244 	if (new == NULL)
245 		return got_error_from_errno("malloc");
246 	new->path = path;
247 	new->path_len = path_len;
248 	new->data = data;
249 	if (pe)
250 		TAILQ_INSERT_AFTER(pathlist, pe, new, entry);
251 	else
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, int freemask)
276 {
277 	struct got_pathlist_entry *pe;
278 
279 	while ((pe = TAILQ_FIRST(pathlist)) != NULL) {
280 		if (freemask & GOT_PATHLIST_FREE_PATH) {
281 			free((char *)pe->path);
282 			pe->path = NULL;
283 		}
284 		if (freemask & GOT_PATHLIST_FREE_DATA) {
285 			free(pe->data);
286 			pe->data = NULL;
287 		}
288 		TAILQ_REMOVE(pathlist, pe, entry);
289 		free(pe);
290 	}
291 }
292 
293 static const struct got_error *
294 make_parent_dirs(const char *abspath)
295 {
296 	const struct got_error *err = NULL;
297 	char *parent;
298 
299 	err = got_path_dirname(&parent, abspath);
300 	if (err)
301 		return err;
302 
303 	if (mkdir(parent, GOT_DEFAULT_DIR_MODE) == -1) {
304 		if (errno == ENOENT) {
305 			err = make_parent_dirs(parent);
306 			if (err)
307 				goto done;
308 			if (mkdir(parent, GOT_DEFAULT_DIR_MODE) == -1) {
309 				err = got_error_from_errno2("mkdir", parent);
310 				goto done;
311 			}
312 		} else
313 			err = got_error_from_errno2("mkdir", parent);
314 	}
315 done:
316 	free(parent);
317 	return err;
318 }
319 
320 const struct got_error *
321 got_path_mkdir(const char *abspath)
322 {
323 	const struct got_error *err = NULL;
324 
325 	if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1) {
326 		if (errno == ENOENT) {
327 			err = make_parent_dirs(abspath);
328 			if (err)
329 				goto done;
330 			if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1)
331 				err = got_error_from_errno2("mkdir", abspath);
332 		} else
333 			err = got_error_from_errno2("mkdir", abspath);
334 	}
335 
336 done:
337 	return err;
338 }
339 
340 int
341 got_path_dir_is_empty(const char *dir)
342 {
343 	DIR *d;
344 	struct dirent *dent;
345 	int empty = 1;
346 
347 	d = opendir(dir);
348 	if (d == NULL)
349 		return 1;
350 
351 	while ((dent = readdir(d)) != NULL) {
352 		if (strcmp(dent->d_name, ".") == 0 ||
353 		    strcmp(dent->d_name, "..") == 0)
354 			continue;
355 
356 		empty = 0;
357 		break;
358 	}
359 
360 	closedir(d);
361 	return empty;
362 }
363 
364 const struct got_error *
365 got_path_dirname(char **parent, const char *path)
366 {
367 	char buf[PATH_MAX];
368 	char *p;
369 
370 	if (strlcpy(buf, path, sizeof(buf)) >= sizeof(buf))
371 		return got_error(GOT_ERR_NO_SPACE);
372 
373 	p = dirname(buf);
374 	if (p == NULL)
375 		return got_error_from_errno2("dirname", path);
376 
377 	if (p[0] == '.' && p[1] == '\0')
378 		return got_error_path(path, GOT_ERR_BAD_PATH);
379 
380 	*parent = strdup(p);
381 	if (*parent == NULL)
382 		return got_error_from_errno("strdup");
383 
384 	return NULL;
385 }
386 
387 const struct got_error *
388 got_path_dirent_type(int *type, const char *path_parent, struct dirent *dent)
389 {
390 	const struct got_error *err = NULL;
391 	char *path_child;
392 	struct stat sb;
393 
394 	if (dent->d_type != DT_UNKNOWN) {
395 		*type = dent->d_type;
396 		return NULL;
397 	}
398 
399 	*type = DT_UNKNOWN;
400 
401 	/*
402 	 * This is a fallback to accommodate filesystems which do not
403 	 * provide directory entry type information. DT_UNKNOWN directory
404 	 * entries occur on NFS mounts without "readdir plus" RPC.
405 	 */
406 
407 	if (asprintf(&path_child, "%s/%s", path_parent, dent->d_name) == -1)
408 		return got_error_from_errno("asprintf");
409 
410 	if (lstat(path_child, &sb) == -1) {
411 		err = got_error_from_errno2("lstat", path_child);
412 		goto done;
413 	}
414 
415 	if (S_ISFIFO(sb.st_mode))
416 		*type = DT_FIFO;
417 	else if (S_ISCHR(sb.st_mode))
418 		*type = DT_CHR;
419 	else if (S_ISDIR(sb.st_mode))
420 		*type = DT_DIR;
421 	else if (S_ISBLK(sb.st_mode))
422 		*type = DT_BLK;
423 	else if (S_ISLNK(sb.st_mode))
424 		*type = DT_LNK;
425 	else if (S_ISREG(sb.st_mode))
426 		*type = DT_REG;
427 	else if (S_ISSOCK(sb.st_mode))
428 		*type = DT_SOCK;
429 done:
430 	free(path_child);
431 	return err;
432 }
433 
434 const struct got_error *
435 got_path_basename(char **s, const char *path)
436 {
437 	char buf[PATH_MAX];
438 	char *base;
439 
440 	if (strlcpy(buf, path, sizeof(buf)) >= sizeof(buf))
441 		return got_error(GOT_ERR_NO_SPACE);
442 
443 	base = basename(buf);
444 	if (base == NULL)
445 		return got_error_from_errno2("basename", path);
446 
447 	*s = strdup(base);
448 	if (*s == NULL)
449 		return got_error_from_errno("strdup");
450 
451 	return NULL;
452 }
453 
454 void
455 got_path_strip_trailing_slashes(char *path)
456 {
457 	size_t x;
458 
459 	x = strlen(path);
460 	while (x-- > 0 && path[x] == '/')
461 		path[x] = '\0';
462 }
463 
464 /* based on findprog() from usr.bin/which/which.c */
465 const struct got_error *
466 got_path_find_prog(char **filename, const char *prog)
467 {
468 	const struct got_error *err = NULL;
469 	const char *path;
470 	char *p;
471 	int len;
472 	struct stat sbuf;
473 	char *pathcpy, *dup = NULL;
474 
475 	*filename = NULL;
476 
477 	path = getenv("PATH");
478 	if (path == NULL)
479 		path = _PATH_DEFPATH;
480 
481 	/* Special case if prog contains '/' */
482 	if (strchr(prog, '/')) {
483 		if ((stat(prog, &sbuf) == 0) && S_ISREG(sbuf.st_mode) &&
484 		    access(prog, X_OK) == 0) {
485 			*filename = strdup(prog);
486 			if (*filename == NULL)
487 				return got_error_from_errno("strdup");
488 		}
489 		return NULL;
490 	}
491 
492 	if ((dup = strdup(path)) == NULL)
493 		return got_error_from_errno("strdup");
494 	pathcpy = dup;
495 
496 	while ((p = strsep(&pathcpy, ":")) != NULL) {
497 		const char *d;
498 
499 		len = strlen(p);
500 		while (len > 0 && p[len-1] == '/')
501 			p[--len] = '\0';	/* strip trailing '/' */
502 
503 		d = p;
504 		if (*d == '\0')
505 			d = ".";
506 
507 		if (asprintf(filename, "%s/%s", d, prog) == -1) {
508 			err = got_error_from_errno("asprintf");
509 			break;
510 		}
511 		if ((stat(*filename, &sbuf) == 0) && S_ISREG(sbuf.st_mode) &&
512 		    access(*filename, X_OK) == 0)
513 			break;
514 		free(*filename);
515 		*filename = NULL;
516 	}
517 	free(dup);
518 	return err;
519 }
520 
521 const struct got_error *
522 got_path_create_file(const char *path, const char *content)
523 {
524 	const struct got_error *err = NULL;
525 	int fd = -1;
526 
527 	fd = open(path, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW | O_CLOEXEC,
528 	    GOT_DEFAULT_FILE_MODE);
529 	if (fd == -1) {
530 		err = got_error_from_errno2("open", path);
531 		goto done;
532 	}
533 
534 	if (content) {
535 		int len = dprintf(fd, "%s\n", content);
536 		if (len != strlen(content) + 1) {
537 			err = got_error_from_errno("dprintf");
538 			goto done;
539 		}
540 	}
541 
542 done:
543 	if (fd != -1 && close(fd) == -1 && err == NULL)
544 		err = got_error_from_errno("close");
545 	return err;
546 }
547 
548 const struct got_error *
549 got_path_move_file(const char *oldpath, const char *newpath)
550 {
551 	const struct got_error *err;
552 
553 	if (rename(oldpath, newpath) != -1)
554 		return NULL;
555 
556 	if (errno != ENOENT)
557 		return got_error_from_errno3("rename", oldpath, newpath);
558 
559 	err = make_parent_dirs(newpath);
560 	if (err)
561 		return err;
562 
563 	if (rename(oldpath, newpath) == -1)
564 		return got_error_from_errno3("rename", oldpath, newpath);
565 
566 	return NULL;
567 }