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Date:: Fri Dec 4 20:27:43 2020 UTC
Message:: remove unused function got_path_get_absolute(); realpath(3) is usually better
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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 int
121 got_path_is_root_dir(const char *path)
122 {
123 	while (*path == '/')
124 		path++;
125 	return (*path == '\0');
126 }
127 
128 int
129 got_path_is_current_dir(const char *path)
130 {
131 	return (path[0] == '.' && path[1] == '\0');
132 }
133 
134 int
135 got_path_is_child(const char *child, const char *parent, size_t parent_len)
136 {
137 	if (parent_len == 0 || got_path_is_root_dir(parent))
138 		return 1;
139 
140 	if (strncmp(parent, child, parent_len) != 0)
141 		return 0;
142 	if (child[parent_len] != '/')
143 		return 0;
144 
145 	return 1;
146 }
147 
148 int
149 got_path_cmp(const char *path1, const char *path2, size_t len1, size_t len2)
150 {
151 	size_t min_len;
152 	size_t i = 0;
153 
154 	/* Leading directory separators are insignificant. */
155 	while (path1[0] == '/') {
156 		path1++;
157 		len1--;
158 	}
159 	while (path2[0] == '/') {
160 		path2++;
161 		len2--;
162 	}
163 
164 	min_len = MIN(len1, len2);
165 
166 	/* Skip over common prefix. */
167 	while (i < min_len && path1[i] == path2[i])
168 		i++;
169 
170 	/* Are the paths exactly equal (besides path separators)? */
171 	if (len1 == len2 && i >= min_len)
172 		return 0;
173 
174 	/* Skip over redundant trailing path seperators. */
175 	while (path1[i] == '/' && path1[i + 1] == '/')
176 		path1++;
177 	while (path2[i] == '/' && path2[i + 1] == '/')
178 		path2++;
179 
180 	/* Trailing path separators are insignificant. */
181 	if (path1[i] == '/' && path1[i + 1] == '\0' && path2[i] == '\0')
182 		return 0;
183 	if (path2[i] == '/' && path2[i + 1] == '\0' && path1[i] == '\0')
184 		return 0;
185 
186 	/* Order children in subdirectories directly after their parents. */
187 	if (path1[i] == '/' && path2[i] == '\0')
188 		return 1;
189 	if (path2[i] == '/' && path1[i] == '\0')
190 		return -1;
191 	if (path1[i] == '/' && path2[i] != '\0')
192 		return -1;
193 	if (path2[i] == '/' && path1[i] != '\0')
194 		return 1;
195 
196 	/* Next character following the common prefix determines order. */
197 	return (unsigned char)path1[i] < (unsigned char)path2[i] ? -1 : 1;
198 }
199 
200 const struct got_error *
201 got_pathlist_insert(struct got_pathlist_entry **inserted,
202     struct got_pathlist_head *pathlist, const char *path, void *data)
203 {
204 	struct got_pathlist_entry *new, *pe;
205 
206 	if (inserted)
207 		*inserted = NULL;
208 
209 	new = malloc(sizeof(*new));
210 	if (new == NULL)
211 		return got_error_from_errno("malloc");
212 	new->path = path;
213 	new->path_len = strlen(path);
214 	new->data = data;
215 
216 	/*
217 	 * Many callers will provide paths in a somewhat sorted order while
218 	 * constructing a path list from inputs such as tree objects or
219 	 * dirents. Iterating backwards from the tail of the list should
220 	 * be more efficient than traversing through the entire list each
221 	 * time an element is inserted.
222 	 */
223 	pe = TAILQ_LAST(pathlist, got_pathlist_head);
224 	while (pe) {
225 		int cmp = got_path_cmp(pe->path, new->path,
226 		    pe->path_len, new->path_len);
227 		if (cmp == 0) {
228 			free(new); /* duplicate */
229 			return NULL;
230 		} else if (cmp < 0) {
231 			TAILQ_INSERT_AFTER(pathlist, pe, new, entry);
232 			if (inserted)
233 				*inserted = new;
234 			return NULL;
235 		}
236 		pe = TAILQ_PREV(pe, got_pathlist_head, entry);
237 	}
238 
239 	TAILQ_INSERT_HEAD(pathlist, new, entry);
240 	if (inserted)
241 		*inserted = new;
242 	return NULL;
243 }
244 
245 const struct got_error *
246 got_pathlist_append(struct got_pathlist_head *pathlist,
247     const char *path, void *data)
248 {
249 	struct got_pathlist_entry *new;
250 
251 	new = malloc(sizeof(*new));
252 	if (new == NULL)
253 		return got_error_from_errno("malloc");
254 	new->path = path;
255 	new->path_len = strlen(path);
256 	new->data = data;
257 	TAILQ_INSERT_TAIL(pathlist, new, entry);
258 	return NULL;
259 }
260 
261 void
262 got_pathlist_free(struct got_pathlist_head *pathlist)
263 {
264 	struct got_pathlist_entry *pe;
265 
266 	while ((pe = TAILQ_FIRST(pathlist)) != NULL) {
267 		TAILQ_REMOVE(pathlist, pe, entry);
268 		free(pe);
269 	}
270 }
271 
272 static const struct got_error *
273 make_parent_dirs(const char *abspath)
274 {
275 	const struct got_error *err = NULL;
276 	char *parent;
277 
278 	err = got_path_dirname(&parent, abspath);
279 	if (err)
280 		return err;
281 
282 	if (mkdir(parent, GOT_DEFAULT_DIR_MODE) == -1) {
283 		if (errno == ENOENT) {
284 			err = make_parent_dirs(parent);
285 			if (err)
286 				goto done;
287 			if (mkdir(parent, GOT_DEFAULT_DIR_MODE) == -1) {
288 				err = got_error_from_errno2("mkdir", parent);
289 				goto done;
290 			}
291 		} else
292 			err = got_error_from_errno2("mkdir", parent);
293 	}
294 done:
295 	free(parent);
296 	return err;
297 }
298 
299 const struct got_error *
300 got_path_mkdir(const char *abspath)
301 {
302 	const struct got_error *err = NULL;
303 
304 	if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1) {
305 		if (errno == ENOENT) {
306 			err = make_parent_dirs(abspath);
307 			if (err)
308 				goto done;
309 			if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1)
310 				err = got_error_from_errno2("mkdir", abspath);
311 		} else
312 			err = got_error_from_errno2("mkdir", abspath);
313 	}
314 
315 done:
316 	return err;
317 }
318 
319 int
320 got_path_dir_is_empty(const char *dir)
321 {
322 	DIR *d;
323 	struct dirent *dent;
324 	int empty = 1;
325 
326 	d = opendir(dir);
327 	if (d == NULL)
328 		return 1;
329 
330 	while ((dent = readdir(d)) != NULL) {
331 		if (strcmp(dent->d_name, ".") == 0 ||
332 		    strcmp(dent->d_name, "..") == 0)
333 			continue;
334 
335 		empty = 0;
336 		break;
337 	}
338 
339 	closedir(d);
340 	return empty;
341 }
342 
343 const struct got_error *
344 got_path_dirname(char **parent, const char *path)
345 {
346 	char buf[PATH_MAX];
347 	char *p;
348 
349 	if (strlcpy(buf, path, sizeof(buf)) >= sizeof(buf))
350 		return got_error(GOT_ERR_NO_SPACE);
351 
352 	p = dirname(buf);
353 	if (p == NULL)
354 		return got_error_from_errno2("dirname", path);
355 
356 	if (p[0] == '.' && p[1] == '\0')
357 		return got_error_path(path, GOT_ERR_BAD_PATH);
358 
359 	*parent = strdup(p);
360 	if (*parent == NULL)
361 		return got_error_from_errno("strdup");
362 
363 	return NULL;
364 }
365 
366 const struct got_error *
367 got_path_dirent_type(int *type, const char *path_parent, struct dirent *dent)
368 {
369 	const struct got_error *err = NULL;
370 	char *path_child;
371 	struct stat sb;
372 
373 	if (dent->d_type != DT_UNKNOWN) {
374 		*type = dent->d_type;
375 		return NULL;
376 	}
377 
378 	*type = DT_UNKNOWN;
379 
380 	/*
381 	 * This is a fallback to accommodate filesystems which do not
382 	 * provide directory entry type information. DT_UNKNOWN directory
383 	 * entries occur on NFS mounts without "readdir plus" RPC.
384 	 */
385 
386 	if (asprintf(&path_child, "%s/%s", path_parent, dent->d_name) == -1)
387 		return got_error_from_errno("asprintf");
388 
389 	if (lstat(path_child, &sb) == -1) {
390 		err = got_error_from_errno2("lstat", path_child);
391 		goto done;
392 	}
393 
394 	if (S_ISFIFO(sb.st_mode))
395 		*type = DT_FIFO;
396 	else if (S_ISCHR(sb.st_mode))
397 		*type = DT_CHR;
398 	else if (S_ISDIR(sb.st_mode))
399 		*type = DT_DIR;
400 	else if (S_ISBLK(sb.st_mode))
401 		*type = DT_BLK;
402 	else if (S_ISLNK(sb.st_mode))
403 		*type = DT_LNK;
404 	else if (S_ISREG(sb.st_mode))
405 		*type = DT_REG;
406 	else if (S_ISSOCK(sb.st_mode))
407 		*type = DT_SOCK;
408 done:
409 	free(path_child);
410 	return err;
411 }
412 
413 const struct got_error *
414 got_path_basename(char **s, const char *path)
415 {
416 	char buf[PATH_MAX];
417 	char *base;
418 
419 	if (strlcpy(buf, path, sizeof(buf)) >= sizeof(buf))
420 		return got_error(GOT_ERR_NO_SPACE);
421 
422 	base = basename(buf);
423 	if (base == NULL)
424 		return got_error_from_errno2("basename", path);
425 
426 	*s = strdup(base);
427 	if (*s == NULL)
428 		return got_error_from_errno("strdup");
429 
430 	return NULL;
431 }
432 
433 void
434 got_path_strip_trailing_slashes(char *path)
435 {
436 	size_t x;
437 
438 	x = strlen(path);
439 	while (x-- > 0 && path[x] == '/')
440 		path[x] = '\0';
441 }
442 
443 /* based on findprog() from usr.sbin/which/which.c */
444 const struct got_error *
445 got_path_find_prog(char **filename, const char *prog)
446 {
447 	const struct got_error *err = NULL;
448 	char *p;
449 	int len;
450 	struct stat sbuf;
451 	char *path, *pathcpy;
452 
453 	*filename = NULL;
454 
455 	path = getenv("PATH");
456 	if (path == NULL)
457 		path = _PATH_DEFPATH;
458 
459 	/* Special case if prog contains '/' */
460 	if (strchr(prog, '/')) {
461 		if ((stat(prog, &sbuf) == 0) && S_ISREG(sbuf.st_mode) &&
462 		    access(prog, X_OK) == 0) {
463 			*filename = strdup(prog);
464 			if (*filename == NULL)
465 				return got_error_from_errno("strdup");
466 		}
467 		return NULL;
468 	}
469 
470 	if ((path = strdup(path)) == NULL)
471 		return got_error_from_errno("strdup");
472 	pathcpy = path;
473 
474 	while ((p = strsep(&pathcpy, ":")) != NULL) {
475 		if (*p == '\0')
476 			p = ".";
477 
478 		len = strlen(p);
479 		while (len > 0 && p[len-1] == '/')
480 			p[--len] = '\0';	/* strip trailing '/' */
481 
482 		if (asprintf(filename, "%s/%s", p, prog) == -1) {
483 			err = got_error_from_errno("asprintf");
484 			break;
485 		}
486 		if ((stat(*filename, &sbuf) == 0) && S_ISREG(sbuf.st_mode) &&
487 		    access(*filename, X_OK) == 0)
488 			break;
489 		free(*filename);
490 		*filename = NULL;
491 		continue;
492 	}
493 	free(path);
494 	return err;
495 }
496 
497 const struct got_error *
498 got_path_create_file(const char *path, const char *content)
499 {
500 	const struct got_error *err = NULL;
501 	int fd = -1;
502 
503 	fd = open(path, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW,
504 	    GOT_DEFAULT_FILE_MODE);
505 	if (fd == -1) {
506 		err = got_error_from_errno2("open", path);
507 		goto done;
508 	}
509 
510 	if (content) {
511 		int len = dprintf(fd, "%s\n", content);
512 		if (len != strlen(content) + 1) {
513 			err = got_error_from_errno("dprintf");
514 			goto done;
515 		}
516 	}
517 
518 done:
519 	if (fd != -1 && close(fd) == -1 && err == NULL)
520 		err = got_error_from_errno("close");
521 	return err;
522 }