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 <sys/stat.h>
18 #include <sys/queue.h>
19 
20 #include <errno.h>
21 #include <fcntl.h>
22 #include <limits.h>
23 #include <sha1.h>
24 #include <sha2.h>
25 #include <stddef.h>
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <unistd.h>
30 #include <uuid.h>
31 
32 #include "got_cancel.h"
33 #include "got_error.h"
34 #include "got_reference.h"
35 #include "got_path.h"
36 #include "got_worktree.h"
37 #include "got_repository.h"
38 #include "got_gotconfig.h"
39 #include "got_object.h"
40 
41 #include "got_lib_worktree.h"
42 #include "got_lib_gotconfig.h"
43 
44 #ifndef nitems
45 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
46 #endif
47 
48 static const struct got_error *
49 read_meta_file(char **content, const char *path_got, const char *name)
50 {
51 	const struct got_error *err = NULL;
52 	char *path;
53 	int fd = -1;
54 	ssize_t n;
55 	struct stat sb;
56 
57 	*content = NULL;
58 
59 	if (asprintf(&path, "%s/%s", path_got, name) == -1) {
60 		err = got_error_from_errno("asprintf");
61 		path = NULL;
62 		goto done;
63 	}
64 
65 	fd = open(path, O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
66 	if (fd == -1) {
67 		if (errno == ENOENT)
68 			err = got_error_path(path, GOT_ERR_WORKTREE_META);
69 		else
70 			err = got_error_from_errno2("open", path);
71 		goto done;
72 	}
73 	if (flock(fd, LOCK_SH | LOCK_NB) == -1) {
74 		err = (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
75 		    : got_error_from_errno2("flock", path));
76 		goto done;
77 	}
78 
79 	if (fstat(fd, &sb) != 0) {
80 		err = got_error_from_errno2("fstat", path);
81 		goto done;
82 	}
83 	if (sb.st_size == 0) {
84 		err = got_error_path(path, GOT_ERR_WORKTREE_META);
85 		goto done;
86 	}
87 	*content = calloc(1, sb.st_size);
88 	if (*content == NULL) {
89 		err = got_error_from_errno("calloc");
90 		goto done;
91 	}
92 
93 	n = read(fd, *content, sb.st_size);
94 	if (n != sb.st_size) {
95 		err = (n == -1 ? got_error_from_errno2("read", path) :
96 		    got_error_path(path, GOT_ERR_WORKTREE_META));
97 		goto done;
98 	}
99 	if ((*content)[sb.st_size - 1] != '\n') {
100 		err = got_error_path(path, GOT_ERR_WORKTREE_META);
101 		goto done;
102 	}
103 	(*content)[sb.st_size - 1] = '\0';
104 
105 done:
106 	if (fd != -1 && close(fd) == -1 && err == NULL)
107 		err = got_error_from_errno2("close", path_got);
108 	free(path);
109 	if (err) {
110 		free(*content);
111 		*content = NULL;
112 	}
113 	return err;
114 }
115 
116 static const struct got_error *
117 open_worktree(struct got_worktree **worktree, const char *path,
118     const char *meta_dir)
119 {
120 	const struct got_error *err = NULL;
121 	char *path_meta;
122 	char *formatstr = NULL;
123 	char *uuidstr = NULL;
124 	char *path_lock = NULL;
125 	char *base_commit_id_str = NULL;
126 	int version, fd = -1;
127 	const char *errstr;
128 	struct got_repository *repo = NULL;
129 	int *pack_fds = NULL;
130 	uint32_t uuid_status;
131 
132 	*worktree = NULL;
133 
134 	if (asprintf(&path_meta, "%s/%s", path, meta_dir) == -1) {
135 		err = got_error_from_errno("asprintf");
136 		path_meta = NULL;
137 		goto done;
138 	}
139 
140 	if (asprintf(&path_lock, "%s/%s", path_meta, GOT_WORKTREE_LOCK) == -1) {
141 		err = got_error_from_errno("asprintf");
142 		path_lock = NULL;
143 		goto done;
144 	}
145 
146 	fd = open(path_lock, O_RDWR | O_EXLOCK | O_NONBLOCK | O_CLOEXEC);
147 	if (fd == -1) {
148 		err = (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
149 		    : got_error_from_errno2("open", path_lock));
150 		goto done;
151 	}
152 
153 	err = read_meta_file(&formatstr, path_meta, GOT_WORKTREE_FORMAT);
154 	if (err)
155 		goto done;
156 
157 	version = strtonum(formatstr, 1, INT_MAX, &errstr);
158 	if (errstr) {
159 		err = got_error_msg(GOT_ERR_WORKTREE_META,
160 		    "could not parse work tree format version number");
161 		goto done;
162 	}
163 	if (version != GOT_WORKTREE_FORMAT_VERSION) {
164 		err = got_error(GOT_ERR_WORKTREE_VERS);
165 		goto done;
166 	}
167 
168 	*worktree = calloc(1, sizeof(**worktree));
169 	if (*worktree == NULL) {
170 		err = got_error_from_errno("calloc");
171 		goto done;
172 	}
173 	(*worktree)->lockfd = -1;
174 
175 	(*worktree)->root_path = realpath(path, NULL);
176 	if ((*worktree)->root_path == NULL) {
177 		err = got_error_from_errno2("realpath", path);
178 		goto done;
179 	}
180 	(*worktree)->meta_dir = meta_dir;
181 	err = read_meta_file(&(*worktree)->repo_path, path_meta,
182 	    GOT_WORKTREE_REPOSITORY);
183 	if (err)
184 		goto done;
185 
186 	err = read_meta_file(&(*worktree)->path_prefix, path_meta,
187 	    GOT_WORKTREE_PATH_PREFIX);
188 	if (err)
189 		goto done;
190 
191 	err = read_meta_file(&base_commit_id_str, path_meta,
192 	    GOT_WORKTREE_BASE_COMMIT);
193 	if (err)
194 		goto done;
195 
196 	err = read_meta_file(&uuidstr, path_meta, GOT_WORKTREE_UUID);
197 	if (err)
198 		goto done;
199 	uuid_from_string(uuidstr, &(*worktree)->uuid, &uuid_status);
200 	if (uuid_status != uuid_s_ok) {
201 		err = got_error_uuid(uuid_status, "uuid_from_string");
202 		goto done;
203 	}
204 
205 	err = got_repo_pack_fds_open(&pack_fds);
206 	if (err)
207 		goto done;
208 
209 	err = got_repo_open(&repo, (*worktree)->repo_path, NULL, pack_fds);
210 	if (err)
211 		goto done;
212 
213 	err = got_object_resolve_id_str(&(*worktree)->base_commit_id, repo,
214 	    base_commit_id_str);
215 	if (err)
216 		goto done;
217 
218 	err = read_meta_file(&(*worktree)->head_ref_name, path_meta,
219 	    GOT_WORKTREE_HEAD_REF);
220 	if (err)
221 		goto done;
222 
223 	if (asprintf(&(*worktree)->gotconfig_path, "%s/%s/%s",
224 	    (*worktree)->root_path, (*worktree)->meta_dir,
225 	    GOT_GOTCONFIG_FILENAME) == -1) {
226 		err = got_error_from_errno("asprintf");
227 		goto done;
228 	}
229 
230 	err = got_gotconfig_read(&(*worktree)->gotconfig,
231 	    (*worktree)->gotconfig_path);
232 	if (err)
233 		goto done;
234 
235 	(*worktree)->root_fd = open((*worktree)->root_path,
236 	    O_DIRECTORY | O_CLOEXEC);
237 	if ((*worktree)->root_fd == -1) {
238 		err = got_error_from_errno2("open", (*worktree)->root_path);
239 		goto done;
240 	}
241 done:
242 	if (repo) {
243 		const struct got_error *close_err = got_repo_close(repo);
244 		if (err == NULL)
245 			err = close_err;
246 	}
247 	if (pack_fds) {
248 		const struct got_error *pack_err =
249 		    got_repo_pack_fds_close(pack_fds);
250 		if (err == NULL)
251 			err = pack_err;
252 	}
253 	free(path_meta);
254 	free(path_lock);
255 	free(base_commit_id_str);
256 	free(uuidstr);
257 	free(formatstr);
258 	if (err) {
259 		if (fd != -1)
260 			close(fd);
261 		if (*worktree != NULL)
262 			got_worktree_close(*worktree);
263 		*worktree = NULL;
264 	} else
265 		(*worktree)->lockfd = fd;
266 
267 	return err;
268 }
269 
270 const struct got_error *
271 got_worktree_open(struct got_worktree **worktree, const char *path,
272     const char *meta_dir)
273 {
274 	const struct got_error *err = NULL;
275 	char *worktree_path;
276 	const char *meta_dirs[] = {
277 		GOT_WORKTREE_GOT_DIR,
278 		GOT_WORKTREE_CVG_DIR
279 	};
280 	int i;
281 
282 	worktree_path = strdup(path);
283 	if (worktree_path == NULL)
284 		return got_error_from_errno("strdup");
285 
286 	for (;;) {
287 		char *parent_path;
288 
289 		if (meta_dir == NULL) {
290 			for (i = 0; i < nitems(meta_dirs); i++) {
291 				err = open_worktree(worktree, worktree_path,
292 				    meta_dirs[i]);
293 				if (err == NULL ||
294 				    err->code == GOT_ERR_WORKTREE_BUSY)
295 					break;
296 			}
297 		} else
298 			err = open_worktree(worktree, worktree_path, meta_dir);
299 		if (err && !(err->code == GOT_ERR_ERRNO && errno == ENOENT)) {
300 			free(worktree_path);
301 			return err;
302 		}
303 		if (*worktree) {
304 			free(worktree_path);
305 			return NULL;
306 		}
307 		if (worktree_path[0] == '/' && worktree_path[1] == '\0')
308 			break;
309 		err = got_path_dirname(&parent_path, worktree_path);
310 		if (err) {
311 			if (err->code != GOT_ERR_BAD_PATH) {
312 				free(worktree_path);
313 				return err;
314 			}
315 			break;
316 		}
317 		free(worktree_path);
318 		worktree_path = parent_path;
319 	}
320 
321 	free(worktree_path);
322 	return got_error(GOT_ERR_NOT_WORKTREE);
323 }
324 
325 const struct got_error *
326 got_worktree_close(struct got_worktree *worktree)
327 {
328 	const struct got_error *err = NULL;
329 
330 	if (worktree->lockfd != -1) {
331 		if (close(worktree->lockfd) == -1)
332 			err = got_error_from_errno2("close",
333 			    got_worktree_get_root_path(worktree));
334 	}
335 	if (close(worktree->root_fd) == -1 && err == NULL)
336 		err = got_error_from_errno2("close",
337 		    got_worktree_get_root_path(worktree));
338 	free(worktree->repo_path);
339 	free(worktree->path_prefix);
340 	free(worktree->base_commit_id);
341 	free(worktree->head_ref_name);
342 	free(worktree->root_path);
343 	free(worktree->gotconfig_path);
344 	got_gotconfig_free(worktree->gotconfig);
345 	free(worktree);
346 	return err;
347 }
348 
349 const char *
350 got_worktree_get_root_path(struct got_worktree *worktree)
351 {
352 	return worktree->root_path;
353 }
354 
355 const char *
356 got_worktree_get_repo_path(struct got_worktree *worktree)
357 {
358 	return worktree->repo_path;
359 }
360 
361 const char *
362 got_worktree_get_path_prefix(struct got_worktree *worktree)
363 {
364 	return worktree->path_prefix;
365 }