1 /*
2  * Copyright (c) 2018, 2019, 2020 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include "got_compat.h"
18 
19 #include <sys/stat.h>
20 #include <sys/queue.h>
21 
22 #include <errno.h>
23 #include <fcntl.h>
24 #include <limits.h>
25 #include <stddef.h>
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <unistd.h>
30 
31 #include "got_cancel.h"
32 #include "got_error.h"
33 #include "got_reference.h"
34 #include "got_path.h"
35 #include "got_worktree.h"
36 #include "got_repository.h"
37 #include "got_gotconfig.h"
38 #include "got_object.h"
39 
40 #include "got_lib_worktree.h"
41 #include "got_lib_gotconfig.h"
42 
43 #ifndef nitems
44 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
45 #endif
46 
47 static const struct got_error *
48 read_meta_file(char **content, const char *path_got, const char *name)
49 {
50 	const struct got_error *err = NULL;
51 	char *path;
52 	int fd = -1;
53 	ssize_t n;
54 	struct stat sb;
55 
56 	*content = NULL;
57 
58 	if (asprintf(&path, "%s/%s", path_got, name) == -1) {
59 		err = got_error_from_errno("asprintf");
60 		path = NULL;
61 		goto done;
62 	}
63 
64 	fd = open(path, O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
65 	if (fd == -1) {
66 		if (errno == ENOENT)
67 			err = got_error_path(path, GOT_ERR_WORKTREE_META);
68 		else
69 			err = got_error_from_errno2("open", path);
70 		goto done;
71 	}
72 	if (flock(fd, LOCK_SH | LOCK_NB) == -1) {
73 		err = (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
74 		    : got_error_from_errno2("flock", path));
75 		goto done;
76 	}
77 
78 	if (fstat(fd, &sb) != 0) {
79 		err = got_error_from_errno2("fstat", path);
80 		goto done;
81 	}
82 	if (sb.st_size == 0) {
83 		err = got_error_path(path, GOT_ERR_WORKTREE_META);
84 		goto done;
85 	}
86 	*content = calloc(1, sb.st_size);
87 	if (*content == NULL) {
88 		err = got_error_from_errno("calloc");
89 		goto done;
90 	}
91 
92 	n = read(fd, *content, sb.st_size);
93 	if (n != sb.st_size) {
94 		err = (n == -1 ? got_error_from_errno2("read", path) :
95 		    got_error_path(path, GOT_ERR_WORKTREE_META));
96 		goto done;
97 	}
98 	if ((*content)[sb.st_size - 1] != '\n') {
99 		err = got_error_path(path, GOT_ERR_WORKTREE_META);
100 		goto done;
101 	}
102 	(*content)[sb.st_size - 1] = '\0';
103 
104 done:
105 	if (fd != -1 && close(fd) == -1 && err == NULL)
106 		err = got_error_from_errno2("close", path_got);
107 	free(path);
108 	if (err) {
109 		free(*content);
110 		*content = NULL;
111 	}
112 	return err;
113 }
114 
115 static const struct got_error *
116 open_worktree(struct got_worktree **worktree, const char *path,
117     const char *meta_dir)
118 {
119 	const struct got_error *err = NULL;
120 	char *path_meta;
121 	char *formatstr = NULL;
122 	char *uuidstr = NULL;
123 	char *path_lock = NULL;
124 	char *base_commit_id_str = NULL;
125 	int version, fd = -1;
126 	const char *errstr;
127 	struct got_repository *repo = NULL;
128 	int *pack_fds = NULL;
129 	uint32_t uuid_status;
130 
131 	*worktree = NULL;
132 
133 	if (asprintf(&path_meta, "%s/%s", path, meta_dir) == -1) {
134 		err = got_error_from_errno("asprintf");
135 		path_meta = NULL;
136 		goto done;
137 	}
138 
139 	if (asprintf(&path_lock, "%s/%s", path_meta, GOT_WORKTREE_LOCK) == -1) {
140 		err = got_error_from_errno("asprintf");
141 		path_lock = NULL;
142 		goto done;
143 	}
144 
145 	fd = open(path_lock, O_RDWR | O_EXLOCK | O_NONBLOCK | O_CLOEXEC);
146 	if (fd == -1) {
147 		err = (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
148 		    : got_error_from_errno2("open", path_lock));
149 		goto done;
150 	}
151 
152 	err = read_meta_file(&formatstr, path_meta, GOT_WORKTREE_FORMAT);
153 	if (err)
154 		goto done;
155 
156 	version = strtonum(formatstr, 1, INT_MAX, &errstr);
157 	if (errstr) {
158 		err = got_error_msg(GOT_ERR_WORKTREE_META,
159 		    "could not parse work tree format version number");
160 		goto done;
161 	}
162 	if (version != GOT_WORKTREE_FORMAT_VERSION) {
163 		err = got_error(GOT_ERR_WORKTREE_VERS);
164 		goto done;
165 	}
166 
167 	*worktree = calloc(1, sizeof(**worktree));
168 	if (*worktree == NULL) {
169 		err = got_error_from_errno("calloc");
170 		goto done;
171 	}
172 	(*worktree)->lockfd = -1;
173 
174 	(*worktree)->root_path = realpath(path, NULL);
175 	if ((*worktree)->root_path == NULL) {
176 		err = got_error_from_errno2("realpath", path);
177 		goto done;
178 	}
179 	(*worktree)->meta_dir = meta_dir;
180 	err = read_meta_file(&(*worktree)->repo_path, path_meta,
181 	    GOT_WORKTREE_REPOSITORY);
182 	if (err)
183 		goto done;
184 
185 	err = read_meta_file(&(*worktree)->path_prefix, path_meta,
186 	    GOT_WORKTREE_PATH_PREFIX);
187 	if (err)
188 		goto done;
189 
190 	err = read_meta_file(&base_commit_id_str, path_meta,
191 	    GOT_WORKTREE_BASE_COMMIT);
192 	if (err)
193 		goto done;
194 
195 	err = read_meta_file(&uuidstr, path_meta, GOT_WORKTREE_UUID);
196 	if (err)
197 		goto done;
198 	uuid_from_string(uuidstr, &(*worktree)->uuid, &uuid_status);
199 	if (uuid_status != uuid_s_ok) {
200 		err = got_error_uuid(uuid_status, "uuid_from_string");
201 		goto done;
202 	}
203 
204 	err = got_repo_pack_fds_open(&pack_fds);
205 	if (err)
206 		goto done;
207 
208 	err = got_repo_open(&repo, (*worktree)->repo_path, NULL, pack_fds);
209 	if (err)
210 		goto done;
211 
212 	err = got_object_resolve_id_str(&(*worktree)->base_commit_id, repo,
213 	    base_commit_id_str);
214 	if (err)
215 		goto done;
216 
217 	err = read_meta_file(&(*worktree)->head_ref_name, path_meta,
218 	    GOT_WORKTREE_HEAD_REF);
219 	if (err)
220 		goto done;
221 
222 	if (asprintf(&(*worktree)->gotconfig_path, "%s/%s/%s",
223 	    (*worktree)->root_path, (*worktree)->meta_dir,
224 	    GOT_GOTCONFIG_FILENAME) == -1) {
225 		err = got_error_from_errno("asprintf");
226 		goto done;
227 	}
228 
229 	err = got_gotconfig_read(&(*worktree)->gotconfig,
230 	    (*worktree)->gotconfig_path);
231 	if (err)
232 		goto done;
233 
234 	(*worktree)->root_fd = open((*worktree)->root_path,
235 	    O_DIRECTORY | O_CLOEXEC);
236 	if ((*worktree)->root_fd == -1) {
237 		err = got_error_from_errno2("open", (*worktree)->root_path);
238 		goto done;
239 	}
240 done:
241 	if (repo) {
242 		const struct got_error *close_err = got_repo_close(repo);
243 		if (err == NULL)
244 			err = close_err;
245 	}
246 	if (pack_fds) {
247 		const struct got_error *pack_err =
248 		    got_repo_pack_fds_close(pack_fds);
249 		if (err == NULL)
250 			err = pack_err;
251 	}
252 	free(path_meta);
253 	free(path_lock);
254 	free(base_commit_id_str);
255 	free(uuidstr);
256 	free(formatstr);
257 	if (err) {
258 		if (fd != -1)
259 			close(fd);
260 		if (*worktree != NULL)
261 			got_worktree_close(*worktree);
262 		*worktree = NULL;
263 	} else
264 		(*worktree)->lockfd = fd;
265 
266 	return err;
267 }
268 
269 const struct got_error *
270 got_worktree_open(struct got_worktree **worktree, const char *path,
271     const char *meta_dir)
272 {
273 	const struct got_error *err = NULL;
274 	char *worktree_path;
275 	const char *meta_dirs[] = {
276 		GOT_WORKTREE_GOT_DIR,
277 		GOT_WORKTREE_CVG_DIR
278 	};
279 	int i;
280 
281 	worktree_path = strdup(path);
282 	if (worktree_path == NULL)
283 		return got_error_from_errno("strdup");
284 
285 	for (;;) {
286 		char *parent_path;
287 
288 		if (meta_dir == NULL) {
289 			for (i = 0; i < nitems(meta_dirs); i++) {
290 				err = open_worktree(worktree, worktree_path,
291 				    meta_dirs[i]);
292 				if (err == NULL ||
293 				    err->code == GOT_ERR_WORKTREE_BUSY)
294 					break;
295 			}
296 		} else
297 			err = open_worktree(worktree, worktree_path, meta_dir);
298 		if (err && !(err->code == GOT_ERR_ERRNO && errno == ENOENT)) {
299 			free(worktree_path);
300 			return err;
301 		}
302 		if (*worktree) {
303 			free(worktree_path);
304 			return NULL;
305 		}
306 		if (worktree_path[0] == '/' && worktree_path[1] == '\0')
307 			break;
308 		err = got_path_dirname(&parent_path, worktree_path);
309 		if (err) {
310 			if (err->code != GOT_ERR_BAD_PATH) {
311 				free(worktree_path);
312 				return err;
313 			}
314 			break;
315 		}
316 		free(worktree_path);
317 		worktree_path = parent_path;
318 	}
319 
320 	free(worktree_path);
321 	return got_error(GOT_ERR_NOT_WORKTREE);
322 }
323 
324 const struct got_error *
325 got_worktree_close(struct got_worktree *worktree)
326 {
327 	const struct got_error *err = NULL;
328 
329 	if (worktree->lockfd != -1) {
330 		if (close(worktree->lockfd) == -1)
331 			err = got_error_from_errno2("close",
332 			    got_worktree_get_root_path(worktree));
333 	}
334 	if (close(worktree->root_fd) == -1 && err == NULL)
335 		err = got_error_from_errno2("close",
336 		    got_worktree_get_root_path(worktree));
337 	free(worktree->repo_path);
338 	free(worktree->path_prefix);
339 	free(worktree->base_commit_id);
340 	free(worktree->head_ref_name);
341 	free(worktree->root_path);
342 	free(worktree->gotconfig_path);
343 	got_gotconfig_free(worktree->gotconfig);
344 	free(worktree);
345 	return err;
346 }
347 
348 const char *
349 got_worktree_get_root_path(struct got_worktree *worktree)
350 {
351 	return worktree->root_path;
352 }
353 
354 const char *
355 got_worktree_get_repo_path(struct got_worktree *worktree)
356 {
357 	return worktree->repo_path;
358 }
359 
360 const char *
361 got_worktree_get_path_prefix(struct got_worktree *worktree)
362 {
363 	return worktree->path_prefix;
364 }