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