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 	uint32_t uuid_status;
117 
118 	*worktree = NULL;
119 
120 	if (asprintf(&path_got, "%s/%s", path, GOT_WORKTREE_GOT_DIR) == -1) {
121 		err = got_error_from_errno("asprintf");
122 		path_got = NULL;
123 		goto done;
124 	}
125 
126 	if (asprintf(&path_lock, "%s/%s", path_got, GOT_WORKTREE_LOCK) == -1) {
127 		err = got_error_from_errno("asprintf");
128 		path_lock = NULL;
129 		goto done;
130 	}
131 
132 	fd = open(path_lock, O_RDWR | O_EXLOCK | O_NONBLOCK | O_CLOEXEC);
133 	if (fd == -1) {
134 		err = (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
135 		    : got_error_from_errno2("open", path_lock));
136 		goto done;
137 	}
138 
139 	err = read_meta_file(&formatstr, path_got, GOT_WORKTREE_FORMAT);
140 	if (err)
141 		goto done;
142 
143 	version = strtonum(formatstr, 1, INT_MAX, &errstr);
144 	if (errstr) {
145 		err = got_error_msg(GOT_ERR_WORKTREE_META,
146 		    "could not parse work tree format version number");
147 		goto done;
148 	}
149 	if (version != GOT_WORKTREE_FORMAT_VERSION) {
150 		err = got_error(GOT_ERR_WORKTREE_VERS);
151 		goto done;
152 	}
153 
154 	*worktree = calloc(1, sizeof(**worktree));
155 	if (*worktree == NULL) {
156 		err = got_error_from_errno("calloc");
157 		goto done;
158 	}
159 	(*worktree)->lockfd = -1;
160 
161 	(*worktree)->root_path = realpath(path, NULL);
162 	if ((*worktree)->root_path == NULL) {
163 		err = got_error_from_errno2("realpath", path);
164 		goto done;
165 	}
166 	err = read_meta_file(&(*worktree)->repo_path, path_got,
167 	    GOT_WORKTREE_REPOSITORY);
168 	if (err)
169 		goto done;
170 
171 	err = read_meta_file(&(*worktree)->path_prefix, path_got,
172 	    GOT_WORKTREE_PATH_PREFIX);
173 	if (err)
174 		goto done;
175 
176 	err = read_meta_file(&base_commit_id_str, path_got,
177 	    GOT_WORKTREE_BASE_COMMIT);
178 	if (err)
179 		goto done;
180 
181 	err = read_meta_file(&uuidstr, path_got, GOT_WORKTREE_UUID);
182 	if (err)
183 		goto done;
184 	uuid_from_string(uuidstr, &(*worktree)->uuid, &uuid_status);
185 	if (uuid_status != uuid_s_ok) {
186 		err = got_error_uuid(uuid_status, "uuid_from_string");
187 		goto done;
188 	}
189 
190 	err = got_repo_open(&repo, (*worktree)->repo_path, NULL);
191 	if (err)
192 		goto done;
193 
194 	err = got_object_resolve_id_str(&(*worktree)->base_commit_id, repo,
195 	    base_commit_id_str);
196 	if (err)
197 		goto done;
198 
199 	err = read_meta_file(&(*worktree)->head_ref_name, path_got,
200 	    GOT_WORKTREE_HEAD_REF);
201 	if (err)
202 		goto done;
203 
204 	if (asprintf(&(*worktree)->gotconfig_path, "%s/%s/%s",
205 	    (*worktree)->root_path,
206 	    GOT_WORKTREE_GOT_DIR, GOT_GOTCONFIG_FILENAME) == -1) {
207 		err = got_error_from_errno("asprintf");
208 		goto done;
209 	}
210 
211 	err = got_gotconfig_read(&(*worktree)->gotconfig,
212 	    (*worktree)->gotconfig_path);
213 
214 	(*worktree)->root_fd = open((*worktree)->root_path,
215 	    O_DIRECTORY | O_CLOEXEC);
216 	if ((*worktree)->root_fd == -1) {
217 		err = got_error_from_errno2("open", (*worktree)->root_path);
218 		goto done;
219 	}
220 done:
221 	if (repo) {
222 		const struct got_error *close_err = got_repo_close(repo);
223 		if (err == NULL)
224 			err = close_err;
225 	}
226 	free(path_got);
227 	free(path_lock);
228 	free(base_commit_id_str);
229 	free(uuidstr);
230 	free(formatstr);
231 	if (err) {
232 		if (fd != -1)
233 			close(fd);
234 		if (*worktree != NULL)
235 			got_worktree_close(*worktree);
236 		*worktree = NULL;
237 	} else
238 		(*worktree)->lockfd = fd;
239 
240 	return err;
241 }
242 
243 const struct got_error *
244 got_worktree_open(struct got_worktree **worktree, const char *path)
245 {
246 	const struct got_error *err = NULL;
247 	char *worktree_path;
248 
249 	worktree_path = strdup(path);
250 	if (worktree_path == NULL)
251 		return got_error_from_errno("strdup");
252 
253 	for (;;) {
254 		char *parent_path;
255 
256 		err = open_worktree(worktree, worktree_path);
257 		if (err && !(err->code == GOT_ERR_ERRNO && errno == ENOENT)) {
258 			free(worktree_path);
259 			return err;
260 		}
261 		if (*worktree) {
262 			free(worktree_path);
263 			return NULL;
264 		}
265 		if (worktree_path[0] == '/' && worktree_path[1] == '\0')
266 			break;
267 		err = got_path_dirname(&parent_path, worktree_path);
268 		if (err) {
269 			if (err->code != GOT_ERR_BAD_PATH) {
270 				free(worktree_path);
271 				return err;
272 			}
273 			break;
274 		}
275 		free(worktree_path);
276 		worktree_path = parent_path;
277 	}
278 
279 	free(worktree_path);
280 	return got_error(GOT_ERR_NOT_WORKTREE);
281 }
282 
283 const struct got_error *
284 got_worktree_close(struct got_worktree *worktree)
285 {
286 	const struct got_error *err = NULL;
287 
288 	if (worktree->lockfd != -1) {
289 		if (close(worktree->lockfd) == -1)
290 			err = got_error_from_errno2("close",
291 			    got_worktree_get_root_path(worktree));
292 	}
293 	if (close(worktree->root_fd) == -1 && err == NULL)
294 		err = got_error_from_errno2("close",
295 		    got_worktree_get_root_path(worktree));
296 	free(worktree->repo_path);
297 	free(worktree->path_prefix);
298 	free(worktree->base_commit_id);
299 	free(worktree->head_ref_name);
300 	free(worktree->root_path);
301 	free(worktree->gotconfig_path);
302 	got_gotconfig_free(worktree->gotconfig);
303 	free(worktree);
304 	return err;
305 }
306 
307 const char *
308 got_worktree_get_root_path(struct got_worktree *worktree)
309 {
310 	return worktree->root_path;
311 }
312 
313 const char *
314 got_worktree_get_repo_path(struct got_worktree *worktree)
315 {
316 	return worktree->repo_path;
317 }
318 
319 const char *
320 got_worktree_get_path_prefix(struct got_worktree *worktree)
321 {
322 	return worktree->path_prefix;
323 }