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