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