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 #include <uuid.h>
28 
29 #include "got_cancel.h"
30 #include "got_error.h"
31 #include "got_reference.h"
32 #include "got_path.h"
33 #include "got_worktree.h"
34 #include "got_repository.h"
35 #include "got_gotconfig.h"
36 #include "got_object.h"
37 
38 #include "got_lib_worktree.h"
39 #include "got_lib_gotconfig.h"
40 
41 static const struct got_error *
42 read_meta_file(char **content, const char *path_got, const char *name)
43 {
44 	const struct got_error *err = NULL;
45 	char *path;
46 	int fd = -1;
47 	ssize_t n;
48 	struct stat sb;
49 
50 	*content = NULL;
51 
52 	if (asprintf(&path, "%s/%s", path_got, name) == -1) {
53 		err = got_error_from_errno("asprintf");
54 		path = NULL;
55 		goto done;
56 	}
57 
58 	fd = open(path, O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
59 	if (fd == -1) {
60 		if (errno == ENOENT)
61 			err = got_error_path(path, GOT_ERR_WORKTREE_META);
62 		else
63 			err = got_error_from_errno2("open", path);
64 		goto done;
65 	}
66 	if (flock(fd, LOCK_SH | LOCK_NB) == -1) {
67 		err = (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
68 		    : got_error_from_errno2("flock", path));
69 		goto done;
70 	}
71 
72 	if (fstat(fd, &sb) != 0) {
73 		err = got_error_from_errno2("fstat", path);
74 		goto done;
75 	}
76 	*content = calloc(1, sb.st_size);
77 	if (*content == NULL) {
78 		err = got_error_from_errno("calloc");
79 		goto done;
80 	}
81 
82 	n = read(fd, *content, sb.st_size);
83 	if (n != sb.st_size) {
84 		err = (n == -1 ? got_error_from_errno2("read", path) :
85 		    got_error_path(path, GOT_ERR_WORKTREE_META));
86 		goto done;
87 	}
88 	if ((*content)[sb.st_size - 1] != '\n') {
89 		err = got_error_path(path, GOT_ERR_WORKTREE_META);
90 		goto done;
91 	}
92 	(*content)[sb.st_size - 1] = '\0';
93 
94 done:
95 	if (fd != -1 && close(fd) == -1 && err == NULL)
96 		err = got_error_from_errno2("close", path_got);
97 	free(path);
98 	if (err) {
99 		free(*content);
100 		*content = NULL;
101 	}
102 	return err;
103 }
104 
105 static const struct got_error *
106 open_worktree(struct got_worktree **worktree, const char *path)
107 {
108 	const struct got_error *err = NULL;
109 	char *path_got;
110 	char *formatstr = NULL;
111 	char *uuidstr = NULL;
112 	char *path_lock = NULL;
113 	char *base_commit_id_str = NULL;
114 	int version, fd = -1;
115 	const char *errstr;
116 	struct got_repository *repo = 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_open(&repo, (*worktree)->repo_path, NULL);
192 	if (err)
193 		goto done;
194 
195 	err = got_object_resolve_id_str(&(*worktree)->base_commit_id, repo,
196 	    base_commit_id_str);
197 	if (err)
198 		goto done;
199 
200 	err = read_meta_file(&(*worktree)->head_ref_name, path_got,
201 	    GOT_WORKTREE_HEAD_REF);
202 	if (err)
203 		goto done;
204 
205 	if (asprintf(&(*worktree)->gotconfig_path, "%s/%s/%s",
206 	    (*worktree)->root_path,
207 	    GOT_WORKTREE_GOT_DIR, GOT_GOTCONFIG_FILENAME) == -1) {
208 		err = got_error_from_errno("asprintf");
209 		goto done;
210 	}
211 
212 	err = got_gotconfig_read(&(*worktree)->gotconfig,
213 	    (*worktree)->gotconfig_path);
214 
215 	(*worktree)->root_fd = open((*worktree)->root_path,
216 	    O_DIRECTORY | O_CLOEXEC);
217 	if ((*worktree)->root_fd == -1) {
218 		err = got_error_from_errno2("open", (*worktree)->root_path);
219 		goto done;
220 	}
221 done:
222 	if (repo) {
223 		const struct got_error *close_err = got_repo_close(repo);
224 		if (err == NULL)
225 			err = close_err;
226 	}
227 	free(path_got);
228 	free(path_lock);
229 	free(base_commit_id_str);
230 	free(uuidstr);
231 	free(formatstr);
232 	if (err) {
233 		if (fd != -1)
234 			close(fd);
235 		if (*worktree != NULL)
236 			got_worktree_close(*worktree);
237 		*worktree = NULL;
238 	} else
239 		(*worktree)->lockfd = fd;
240 
241 	return err;
242 }
243 
244 const struct got_error *
245 got_worktree_open(struct got_worktree **worktree, const char *path)
246 {
247 	const struct got_error *err = NULL;
248 	char *worktree_path;
249 
250 	worktree_path = strdup(path);
251 	if (worktree_path == NULL)
252 		return got_error_from_errno("strdup");
253 
254 	for (;;) {
255 		char *parent_path;
256 
257 		err = open_worktree(worktree, worktree_path);
258 		if (err && !(err->code == GOT_ERR_ERRNO && errno == ENOENT)) {
259 			free(worktree_path);
260 			return err;
261 		}
262 		if (*worktree) {
263 			free(worktree_path);
264 			return NULL;
265 		}
266 		if (worktree_path[0] == '/' && worktree_path[1] == '\0')
267 			break;
268 		err = got_path_dirname(&parent_path, worktree_path);
269 		if (err) {
270 			if (err->code != GOT_ERR_BAD_PATH) {
271 				free(worktree_path);
272 				return err;
273 			}
274 			break;
275 		}
276 		free(worktree_path);
277 		worktree_path = parent_path;
278 	}
279 
280 	free(worktree_path);
281 	return got_error(GOT_ERR_NOT_WORKTREE);
282 }
283 
284 const struct got_error *
285 got_worktree_close(struct got_worktree *worktree)
286 {
287 	const struct got_error *err = NULL;
288 
289 	if (worktree->lockfd != -1) {
290 		if (close(worktree->lockfd) == -1)
291 			err = got_error_from_errno2("close",
292 			    got_worktree_get_root_path(worktree));
293 	}
294 	if (close(worktree->root_fd) == -1 && err == NULL)
295 		err = got_error_from_errno2("close",
296 		    got_worktree_get_root_path(worktree));
297 	free(worktree->repo_path);
298 	free(worktree->path_prefix);
299 	free(worktree->base_commit_id);
300 	free(worktree->head_ref_name);
301 	free(worktree->root_path);
302 	free(worktree->gotconfig_path);
303 	got_gotconfig_free(worktree->gotconfig);
304 	free(worktree);
305 	return err;
306 }
307 
308 const char *
309 got_worktree_get_root_path(struct got_worktree *worktree)
310 {
311 	return worktree->root_path;
312 }
313 
314 const char *
315 got_worktree_get_repo_path(struct got_worktree *worktree)
316 {
317 	return worktree->repo_path;
318 }
319 
320 const char *
321 got_worktree_get_path_prefix(struct got_worktree *worktree)
322 {
323 	return worktree->path_prefix;
324 }