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 <sha1.h>
24 #include <stddef.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <string.h>
28 #include <unistd.h>
29 #include <uuid.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 static const struct got_error *
44 read_meta_file(char **content, const char *path_got, const char *name)
45 {
46 	const struct got_error *err = NULL;
47 	char *path;
48 	int fd = -1;
49 	ssize_t n;
50 	struct stat sb;
51 
52 	*content = NULL;
53 
54 	if (asprintf(&path, "%s/%s", path_got, name) == -1) {
55 		err = got_error_from_errno("asprintf");
56 		path = NULL;
57 		goto done;
58 	}
59 
60 	fd = open(path, O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
61 	if (fd == -1) {
62 		if (errno == ENOENT)
63 			err = got_error_path(path, GOT_ERR_WORKTREE_META);
64 		else
65 			err = got_error_from_errno2("open", path);
66 		goto done;
67 	}
68 	if (flock(fd, LOCK_SH | LOCK_NB) == -1) {
69 		err = (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
70 		    : got_error_from_errno2("flock", path));
71 		goto done;
72 	}
73 
74 	if (fstat(fd, &sb) != 0) {
75 		err = got_error_from_errno2("fstat", path);
76 		goto done;
77 	}
78 	*content = calloc(1, sb.st_size);
79 	if (*content == NULL) {
80 		err = got_error_from_errno("calloc");
81 		goto done;
82 	}
83 
84 	n = read(fd, *content, sb.st_size);
85 	if (n != sb.st_size) {
86 		err = (n == -1 ? got_error_from_errno2("read", path) :
87 		    got_error_path(path, GOT_ERR_WORKTREE_META));
88 		goto done;
89 	}
90 	if ((*content)[sb.st_size - 1] != '\n') {
91 		err = got_error_path(path, GOT_ERR_WORKTREE_META);
92 		goto done;
93 	}
94 	(*content)[sb.st_size - 1] = '\0';
95 
96 done:
97 	if (fd != -1 && close(fd) == -1 && err == NULL)
98 		err = got_error_from_errno2("close", path_got);
99 	free(path);
100 	if (err) {
101 		free(*content);
102 		*content = NULL;
103 	}
104 	return err;
105 }
106 
107 static const struct got_error *
108 open_worktree(struct got_worktree **worktree, const char *path)
109 {
110 	const struct got_error *err = NULL;
111 	char *path_got;
112 	char *formatstr = NULL;
113 	char *uuidstr = NULL;
114 	char *path_lock = NULL;
115 	char *base_commit_id_str = NULL;
116 	int version, fd = -1;
117 	const char *errstr;
118 	struct got_repository *repo = NULL;
119 	uint32_t uuid_status;
120 
121 	*worktree = NULL;
122 
123 	if (asprintf(&path_got, "%s/%s", path, GOT_WORKTREE_GOT_DIR) == -1) {
124 		err = got_error_from_errno("asprintf");
125 		path_got = NULL;
126 		goto done;
127 	}
128 
129 	if (asprintf(&path_lock, "%s/%s", path_got, GOT_WORKTREE_LOCK) == -1) {
130 		err = got_error_from_errno("asprintf");
131 		path_lock = NULL;
132 		goto done;
133 	}
134 
135 	fd = open(path_lock, O_RDWR | O_EXLOCK | O_NONBLOCK | O_CLOEXEC);
136 	if (fd == -1) {
137 		err = (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
138 		    : got_error_from_errno2("open", path_lock));
139 		goto done;
140 	}
141 
142 	err = read_meta_file(&formatstr, path_got, GOT_WORKTREE_FORMAT);
143 	if (err)
144 		goto done;
145 
146 	version = strtonum(formatstr, 1, INT_MAX, &errstr);
147 	if (errstr) {
148 		err = got_error_msg(GOT_ERR_WORKTREE_META,
149 		    "could not parse work tree format version number");
150 		goto done;
151 	}
152 	if (version != GOT_WORKTREE_FORMAT_VERSION) {
153 		err = got_error(GOT_ERR_WORKTREE_VERS);
154 		goto done;
155 	}
156 
157 	*worktree = calloc(1, sizeof(**worktree));
158 	if (*worktree == NULL) {
159 		err = got_error_from_errno("calloc");
160 		goto done;
161 	}
162 	(*worktree)->lockfd = -1;
163 
164 	(*worktree)->root_path = realpath(path, NULL);
165 	if ((*worktree)->root_path == NULL) {
166 		err = got_error_from_errno2("realpath", path);
167 		goto done;
168 	}
169 	err = read_meta_file(&(*worktree)->repo_path, path_got,
170 	    GOT_WORKTREE_REPOSITORY);
171 	if (err)
172 		goto done;
173 
174 	err = read_meta_file(&(*worktree)->path_prefix, path_got,
175 	    GOT_WORKTREE_PATH_PREFIX);
176 	if (err)
177 		goto done;
178 
179 	err = read_meta_file(&base_commit_id_str, path_got,
180 	    GOT_WORKTREE_BASE_COMMIT);
181 	if (err)
182 		goto done;
183 
184 	err = read_meta_file(&uuidstr, path_got, GOT_WORKTREE_UUID);
185 	if (err)
186 		goto done;
187 	uuid_from_string(uuidstr, &(*worktree)->uuid, &uuid_status);
188 	if (uuid_status != uuid_s_ok) {
189 		err = got_error_uuid(uuid_status, "uuid_from_string");
190 		goto done;
191 	}
192 
193 	err = got_repo_open(&repo, (*worktree)->repo_path, NULL);
194 	if (err)
195 		goto done;
196 
197 	err = got_object_resolve_id_str(&(*worktree)->base_commit_id, repo,
198 	    base_commit_id_str);
199 	if (err)
200 		goto done;
201 
202 	err = read_meta_file(&(*worktree)->head_ref_name, path_got,
203 	    GOT_WORKTREE_HEAD_REF);
204 	if (err)
205 		goto done;
206 
207 	if (asprintf(&(*worktree)->gotconfig_path, "%s/%s/%s",
208 	    (*worktree)->root_path,
209 	    GOT_WORKTREE_GOT_DIR, GOT_GOTCONFIG_FILENAME) == -1) {
210 		err = got_error_from_errno("asprintf");
211 		goto done;
212 	}
213 
214 	err = got_gotconfig_read(&(*worktree)->gotconfig,
215 	    (*worktree)->gotconfig_path);
216 
217 	(*worktree)->root_fd = open((*worktree)->root_path,
218 	    O_DIRECTORY | O_CLOEXEC);
219 	if ((*worktree)->root_fd == -1) {
220 		err = got_error_from_errno2("open", (*worktree)->root_path);
221 		goto done;
222 	}
223 done:
224 	if (repo) {
225 		const struct got_error *close_err = got_repo_close(repo);
226 		if (err == NULL)
227 			err = close_err;
228 	}
229 	free(path_got);
230 	free(path_lock);
231 	free(base_commit_id_str);
232 	free(uuidstr);
233 	free(formatstr);
234 	if (err) {
235 		if (fd != -1)
236 			close(fd);
237 		if (*worktree != NULL)
238 			got_worktree_close(*worktree);
239 		*worktree = NULL;
240 	} else
241 		(*worktree)->lockfd = fd;
242 
243 	return err;
244 }
245 
246 const struct got_error *
247 got_worktree_open(struct got_worktree **worktree, const char *path)
248 {
249 	const struct got_error *err = NULL;
250 	char *worktree_path;
251 
252 	worktree_path = strdup(path);
253 	if (worktree_path == NULL)
254 		return got_error_from_errno("strdup");
255 
256 	for (;;) {
257 		char *parent_path;
258 
259 		err = open_worktree(worktree, worktree_path);
260 		if (err && !(err->code == GOT_ERR_ERRNO && errno == ENOENT)) {
261 			free(worktree_path);
262 			return err;
263 		}
264 		if (*worktree) {
265 			free(worktree_path);
266 			return NULL;
267 		}
268 		if (worktree_path[0] == '/' && worktree_path[1] == '\0')
269 			break;
270 		err = got_path_dirname(&parent_path, worktree_path);
271 		if (err) {
272 			if (err->code != GOT_ERR_BAD_PATH) {
273 				free(worktree_path);
274 				return err;
275 			}
276 			break;
277 		}
278 		free(worktree_path);
279 		worktree_path = parent_path;
280 	}
281 
282 	free(worktree_path);
283 	return got_error(GOT_ERR_NOT_WORKTREE);
284 }
285 
286 const struct got_error *
287 got_worktree_close(struct got_worktree *worktree)
288 {
289 	const struct got_error *err = NULL;
290 
291 	if (worktree->lockfd != -1) {
292 		if (close(worktree->lockfd) == -1)
293 			err = got_error_from_errno2("close",
294 			    got_worktree_get_root_path(worktree));
295 	}
296 	if (close(worktree->root_fd) == -1 && err == NULL)
297 		err = got_error_from_errno2("close",
298 		    got_worktree_get_root_path(worktree));
299 	free(worktree->repo_path);
300 	free(worktree->path_prefix);
301 	free(worktree->base_commit_id);
302 	free(worktree->head_ref_name);
303 	free(worktree->root_path);
304 	free(worktree->gotconfig_path);
305 	got_gotconfig_free(worktree->gotconfig);
306 	free(worktree);
307 	return err;
308 }
309 
310 const char *
311 got_worktree_get_root_path(struct got_worktree *worktree)
312 {
313 	return worktree->root_path;
314 }
315 
316 const char *
317 got_worktree_get_repo_path(struct got_worktree *worktree)
318 {
319 	return worktree->repo_path;
320 }
321 
322 const char *
323 got_worktree_get_path_prefix(struct got_worktree *worktree)
324 {
325 	return worktree->path_prefix;
326 }