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