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 "got_compat.h"
18 
19 #include <sys/stat.h>
20 #include <sys/queue.h>
21 
22 #include <errno.h>
23 #include <fcntl.h>
24 #include <limits.h>
25 #include <stddef.h>
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <unistd.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 #ifndef nitems
44 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
45 #endif
46 
47 static const struct got_error *
48 read_meta_file(char **content, const char *path_got, const char *name)
49 {
50 	const struct got_error *err = NULL;
51 	char *path;
52 	int fd = -1;
53 	ssize_t n;
54 	struct stat sb;
55 
56 	*content = NULL;
57 
58 	if (asprintf(&path, "%s/%s", path_got, name) == -1) {
59 		err = got_error_from_errno("asprintf");
60 		path = NULL;
61 		goto done;
62 	}
63 
64 	fd = open(path, O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
65 	if (fd == -1) {
66 		if (errno == ENOENT)
67 			err = got_error_path(path, GOT_ERR_WORKTREE_META);
68 		else
69 			err = got_error_from_errno2("open", path);
70 		goto done;
71 	}
72 	if (flock(fd, LOCK_SH | LOCK_NB) == -1) {
73 		err = (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
74 		    : got_error_from_errno2("flock", path));
75 		goto done;
76 	}
77 
78 	if (fstat(fd, &sb) != 0) {
79 		err = got_error_from_errno2("fstat", path);
80 		goto done;
81 	}
82 	*content = calloc(1, sb.st_size);
83 	if (*content == NULL) {
84 		err = got_error_from_errno("calloc");
85 		goto done;
86 	}
87 
88 	n = read(fd, *content, sb.st_size);
89 	if (n != sb.st_size) {
90 		err = (n == -1 ? got_error_from_errno2("read", path) :
91 		    got_error_path(path, GOT_ERR_WORKTREE_META));
92 		goto done;
93 	}
94 	if ((*content)[sb.st_size - 1] != '\n') {
95 		err = got_error_path(path, GOT_ERR_WORKTREE_META);
96 		goto done;
97 	}
98 	(*content)[sb.st_size - 1] = '\0';
99 
100 done:
101 	if (fd != -1 && close(fd) == -1 && err == NULL)
102 		err = got_error_from_errno2("close", path_got);
103 	free(path);
104 	if (err) {
105 		free(*content);
106 		*content = NULL;
107 	}
108 	return err;
109 }
110 
111 static const struct got_error *
112 open_worktree(struct got_worktree **worktree, const char *path,
113     const char *meta_dir)
114 {
115 	const struct got_error *err = NULL;
116 	char *path_meta;
117 	char *formatstr = NULL;
118 	char *uuidstr = NULL;
119 	char *path_lock = NULL;
120 	char *base_commit_id_str = NULL;
121 	int version, fd = -1;
122 	const char *errstr;
123 	struct got_repository *repo = NULL;
124 	int *pack_fds = NULL;
125 	uint32_t uuid_status;
126 
127 	*worktree = NULL;
128 
129 	if (asprintf(&path_meta, "%s/%s", path, meta_dir) == -1) {
130 		err = got_error_from_errno("asprintf");
131 		path_meta = NULL;
132 		goto done;
133 	}
134 
135 	if (asprintf(&path_lock, "%s/%s", path_meta, GOT_WORKTREE_LOCK) == -1) {
136 		err = got_error_from_errno("asprintf");
137 		path_lock = NULL;
138 		goto done;
139 	}
140 
141 	fd = open(path_lock, O_RDWR | O_EXLOCK | O_NONBLOCK | O_CLOEXEC);
142 	if (fd == -1) {
143 		err = (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
144 		    : got_error_from_errno2("open", path_lock));
145 		goto done;
146 	}
147 
148 	err = read_meta_file(&formatstr, path_meta, GOT_WORKTREE_FORMAT);
149 	if (err)
150 		goto done;
151 
152 	version = strtonum(formatstr, 1, INT_MAX, &errstr);
153 	if (errstr) {
154 		err = got_error_msg(GOT_ERR_WORKTREE_META,
155 		    "could not parse work tree format version number");
156 		goto done;
157 	}
158 	if (version != GOT_WORKTREE_FORMAT_VERSION) {
159 		err = got_error(GOT_ERR_WORKTREE_VERS);
160 		goto done;
161 	}
162 
163 	*worktree = calloc(1, sizeof(**worktree));
164 	if (*worktree == NULL) {
165 		err = got_error_from_errno("calloc");
166 		goto done;
167 	}
168 	(*worktree)->lockfd = -1;
169 
170 	(*worktree)->root_path = realpath(path, NULL);
171 	if ((*worktree)->root_path == NULL) {
172 		err = got_error_from_errno2("realpath", path);
173 		goto done;
174 	}
175 	(*worktree)->meta_dir = meta_dir;
176 	err = read_meta_file(&(*worktree)->repo_path, path_meta,
177 	    GOT_WORKTREE_REPOSITORY);
178 	if (err)
179 		goto done;
180 
181 	err = read_meta_file(&(*worktree)->path_prefix, path_meta,
182 	    GOT_WORKTREE_PATH_PREFIX);
183 	if (err)
184 		goto done;
185 
186 	err = read_meta_file(&base_commit_id_str, path_meta,
187 	    GOT_WORKTREE_BASE_COMMIT);
188 	if (err)
189 		goto done;
190 
191 	err = read_meta_file(&uuidstr, path_meta, GOT_WORKTREE_UUID);
192 	if (err)
193 		goto done;
194 	uuid_from_string(uuidstr, &(*worktree)->uuid, &uuid_status);
195 	if (uuid_status != uuid_s_ok) {
196 		err = got_error_uuid(uuid_status, "uuid_from_string");
197 		goto done;
198 	}
199 
200 	err = got_repo_pack_fds_open(&pack_fds);
201 	if (err)
202 		goto done;
203 
204 	err = got_repo_open(&repo, (*worktree)->repo_path, NULL, pack_fds);
205 	if (err)
206 		goto done;
207 
208 	err = got_object_resolve_id_str(&(*worktree)->base_commit_id, repo,
209 	    base_commit_id_str);
210 	if (err)
211 		goto done;
212 
213 	err = read_meta_file(&(*worktree)->head_ref_name, path_meta,
214 	    GOT_WORKTREE_HEAD_REF);
215 	if (err)
216 		goto done;
217 
218 	if (asprintf(&(*worktree)->gotconfig_path, "%s/%s/%s",
219 	    (*worktree)->root_path, (*worktree)->meta_dir,
220 	    GOT_GOTCONFIG_FILENAME) == -1) {
221 		err = got_error_from_errno("asprintf");
222 		goto done;
223 	}
224 
225 	err = got_gotconfig_read(&(*worktree)->gotconfig,
226 	    (*worktree)->gotconfig_path);
227 	if (err)
228 		goto done;
229 
230 	(*worktree)->root_fd = open((*worktree)->root_path,
231 	    O_DIRECTORY | O_CLOEXEC);
232 	if ((*worktree)->root_fd == -1) {
233 		err = got_error_from_errno2("open", (*worktree)->root_path);
234 		goto done;
235 	}
236 done:
237 	if (repo) {
238 		const struct got_error *close_err = got_repo_close(repo);
239 		if (err == NULL)
240 			err = close_err;
241 	}
242 	if (pack_fds) {
243 		const struct got_error *pack_err =
244 		    got_repo_pack_fds_close(pack_fds);
245 		if (err == NULL)
246 			err = pack_err;
247 	}
248 	free(path_meta);
249 	free(path_lock);
250 	free(base_commit_id_str);
251 	free(uuidstr);
252 	free(formatstr);
253 	if (err) {
254 		if (fd != -1)
255 			close(fd);
256 		if (*worktree != NULL)
257 			got_worktree_close(*worktree);
258 		*worktree = NULL;
259 	} else
260 		(*worktree)->lockfd = fd;
261 
262 	return err;
263 }
264 
265 const struct got_error *
266 got_worktree_open(struct got_worktree **worktree, const char *path,
267     const char *meta_dir)
268 {
269 	const struct got_error *err = NULL;
270 	char *worktree_path;
271 	const char *meta_dirs[] = {
272 		GOT_WORKTREE_GOT_DIR,
273 		GOT_WORKTREE_CVG_DIR
274 	};
275 	int i;
276 
277 	worktree_path = strdup(path);
278 	if (worktree_path == NULL)
279 		return got_error_from_errno("strdup");
280 
281 	for (;;) {
282 		char *parent_path;
283 
284 		if (meta_dir == NULL) {
285 			for (i = 0; i < nitems(meta_dirs); i++) {
286 				err = open_worktree(worktree, worktree_path,
287 				    meta_dirs[i]);
288 				if (err == NULL)
289 					break;
290 			}
291 		} else
292 			err = open_worktree(worktree, worktree_path, meta_dir);
293 		if (err && !(err->code == GOT_ERR_ERRNO && errno == ENOENT)) {
294 			free(worktree_path);
295 			return err;
296 		}
297 		if (*worktree) {
298 			free(worktree_path);
299 			return NULL;
300 		}
301 		if (worktree_path[0] == '/' && worktree_path[1] == '\0')
302 			break;
303 		err = got_path_dirname(&parent_path, worktree_path);
304 		if (err) {
305 			if (err->code != GOT_ERR_BAD_PATH) {
306 				free(worktree_path);
307 				return err;
308 			}
309 			break;
310 		}
311 		free(worktree_path);
312 		worktree_path = parent_path;
313 	}
314 
315 	free(worktree_path);
316 	return got_error(GOT_ERR_NOT_WORKTREE);
317 }
318 
319 const struct got_error *
320 got_worktree_close(struct got_worktree *worktree)
321 {
322 	const struct got_error *err = NULL;
323 
324 	if (worktree->lockfd != -1) {
325 		if (close(worktree->lockfd) == -1)
326 			err = got_error_from_errno2("close",
327 			    got_worktree_get_root_path(worktree));
328 	}
329 	if (close(worktree->root_fd) == -1 && err == NULL)
330 		err = got_error_from_errno2("close",
331 		    got_worktree_get_root_path(worktree));
332 	free(worktree->repo_path);
333 	free(worktree->path_prefix);
334 	free(worktree->base_commit_id);
335 	free(worktree->head_ref_name);
336 	free(worktree->root_path);
337 	free(worktree->gotconfig_path);
338 	got_gotconfig_free(worktree->gotconfig);
339 	free(worktree);
340 	return err;
341 }
342 
343 const char *
344 got_worktree_get_root_path(struct got_worktree *worktree)
345 {
346 	return worktree->root_path;
347 }
348 
349 const char *
350 got_worktree_get_repo_path(struct got_worktree *worktree)
351 {
352 	return worktree->repo_path;
353 }
354 
355 const char *
356 got_worktree_get_path_prefix(struct got_worktree *worktree)
357 {
358 	return worktree->path_prefix;
359 }