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