1 /*
2  * Copyright (c) 2018 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/queue.h>
18 
19 #include <errno.h>
20 #include <limits.h>
21 #include <stdarg.h>
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <sha1.h>
26 #include <sha2.h>
27 #include <zlib.h>
28 #include <uuid.h>
29 
30 #include "got_error.h"
31 #include "got_object.h"
32 
33 #include "got_lib_delta.h"
34 #include "got_lib_inflate.h"
35 #include "got_lib_object.h"
36 #include "got_lib_hash.h"
37 #include "got_lib_object_parse.h"
38 
39 #ifndef nitems
40 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
41 #endif
42 
43 static const struct got_error got_errors[] = {
44 	{ GOT_ERR_OK,		"no error occurred?!?" },
45 	{ GOT_ERR_ERRNO,	"see errno" },
46 	{ GOT_ERR_NOT_GIT_REPO, "no git repository found" },
47 	{ GOT_ERR_BAD_FILETYPE,	"bad file type" },
48 	{ GOT_ERR_BAD_PATH,	"bad path" },
49 	{ GOT_ERR_NOT_REF,	"no such reference found" },
50 	{ GOT_ERR_IO,		"input/output error" },
51 	{ GOT_ERR_EOF,		"unexpected end of file" },
52 	{ GOT_ERR_DECOMPRESSION,"decompression failed" },
53 	{ GOT_ERR_NO_SPACE,	"buffer too small" },
54 	{ GOT_ERR_BAD_OBJ_HDR,	"bad object header" },
55 	{ GOT_ERR_OBJ_TYPE,	"wrong type of object" },
56 	{ GOT_ERR_BAD_OBJ_DATA,	"bad object data" },
57 	{ GOT_ERR_AMBIGUOUS_ID, "ambiguous object ID" },
58 	{ GOT_ERR_BAD_PACKIDX,	"bad pack index file" },
59 	{ GOT_ERR_PACKIDX_CSUM, "pack index file checksum error" },
60 	{ GOT_ERR_BAD_PACKFILE,	"bad pack file" },
61 	{ GOT_ERR_NO_OBJ,	"object not found" },
62 	{ GOT_ERR_NOT_IMPL,	"feature not implemented" },
63 	{ GOT_ERR_OBJ_NOT_PACKED,"object is not packed" },
64 	{ GOT_ERR_BAD_DELTA_CHAIN,"bad delta chain" },
65 	{ GOT_ERR_BAD_DELTA,	"bad delta" },
66 	{ GOT_ERR_COMPRESSION,	"compression failed" },
67 	{ GOT_ERR_BAD_OBJ_ID_STR,"bad object id string" },
68 	{ GOT_ERR_WORKTREE_EXISTS,"worktree already exists" },
69 	{ GOT_ERR_WORKTREE_META,"bad worktree meta data" },
70 	{ GOT_ERR_WORKTREE_VERS,"unsupported worktree format version" },
71 	{ GOT_ERR_WORKTREE_BUSY,"worktree already locked" },
72 	{ GOT_ERR_FILE_OBSTRUCTED,"file is obstructed" },
73 	{ GOT_ERR_RECURSION,	"recursion limit reached" },
74 	{ GOT_ERR_TIMEOUT,	"operation timed out" },
75 	{ GOT_ERR_INTERRUPT,	"operation interrupted" },
76 	{ GOT_ERR_PRIVSEP_READ,	"no data received in imsg" },
77 	{ GOT_ERR_PRIVSEP_LEN,	"unexpected amount of data received in imsg" },
78 	{ GOT_ERR_PRIVSEP_PIPE,	"privsep peer process closed pipe" },
79 	{ GOT_ERR_PRIVSEP_NO_FD,"privsep file descriptor unavailable" },
80 	{ GOT_ERR_PRIVSEP_MSG,	"received unexpected privsep message" },
81 	{ GOT_ERR_PRIVSEP_DIED,	"unprivileged process died unexpectedly" },
82 	{ GOT_ERR_PRIVSEP_EXIT,	"bad exit code from unprivileged process" },
83 	{ GOT_ERR_PACK_OFFSET,	"bad offset in pack file" },
84 	{ GOT_ERR_OBJ_EXISTS,	"object already exists" },
85 	{ GOT_ERR_BAD_OBJ_ID,	"bad object id" },
86 	{ GOT_ERR_ITER_COMPLETED,"iteration completed" },
87 	{ GOT_ERR_RANGE,	"value out of range" },
88 	{ GOT_ERR_EXPECTED,	"expected an error but have no error" },
89 	{ GOT_ERR_CANCELLED,	"operation in progress has been cancelled" },
90 	{ GOT_ERR_NO_TREE_ENTRY,"no such entry found in tree" },
91 	{ GOT_ERR_FILEIDX_SIG,	"bad file index signature" },
92 	{ GOT_ERR_FILEIDX_VER,	"unknown file index format version" },
93 	{ GOT_ERR_FILEIDX_CSUM,	"bad file index checksum" },
94 	{ GOT_ERR_PATH_PREFIX,	"worktree already contains items from a "
95 				"different path prefix" },
96 	{ GOT_ERR_ANCESTRY,	"target commit is on a different branch" },
97 	{ GOT_ERR_FILEIDX_BAD,	"file index is corrupt" },
98 	{ GOT_ERR_BAD_REF_DATA,	"could not parse reference data" },
99 	{ GOT_ERR_TREE_DUP_ENTRY,"duplicate entry in tree object" },
100 	{ GOT_ERR_DIR_DUP_ENTRY,"duplicate entry in directory" },
101 	{ GOT_ERR_NOT_WORKTREE, "no work tree found" },
102 	{ GOT_ERR_UUID_VERSION, "bad uuid version" },
103 	{ GOT_ERR_UUID_INVALID, "uuid invalid" },
104 	{ GOT_ERR_UUID,		"uuid error" },
105 	{ GOT_ERR_LOCKFILE_TIMEOUT,"lockfile timeout" },
106 	{ GOT_ERR_BAD_REF_NAME,	"bad reference name" },
107 	{ GOT_ERR_WORKTREE_REPO,"cannot create worktree inside a git repository" },
108 	{ GOT_ERR_FILE_MODIFIED,"file contains modifications" },
109 	{ GOT_ERR_FILE_STATUS,	"file has unexpected status" },
110 	{ GOT_ERR_COMMIT_CONFLICT,"cannot commit file in conflicted status" },
111 	{ GOT_ERR_BAD_REF_TYPE,	"bad reference type" },
112 	{ GOT_ERR_COMMIT_NO_AUTHOR,"GOT_AUTHOR environment variable is not set" },
113 	{ GOT_ERR_COMMIT_HEAD_CHANGED, "branch head in repository has changed "
114 	    "while commit was in progress" },
115 	{ GOT_ERR_COMMIT_OUT_OF_DATE, "work tree must be updated before these "
116 	    "changes can be committed" },
117 	{ GOT_ERR_COMMIT_MSG_EMPTY, "commit message cannot be empty" },
118 	{ GOT_ERR_DIR_NOT_EMPTY, "directory exists and is not empty" },
119 	{ GOT_ERR_COMMIT_NO_CHANGES, "no changes to commit" },
120 	{ GOT_ERR_BRANCH_MOVED,	"work tree's head reference now points to a "
121 	    "different branch; new head reference and/or update -b required" },
122 	{ GOT_ERR_OBJ_TOO_LARGE,	"object too large" },
123 	{ GOT_ERR_SAME_BRANCH,	"commit is already contained in this branch" },
124 	{ GOT_ERR_ROOT_COMMIT,	"specified commit has no parent commit" },
125 	{ GOT_ERR_MIXED_COMMITS,"work tree contains files from multiple "
126 	    "base commits; the entire work tree must be updated first" },
127 	{ GOT_ERR_CONFLICTS,	"work tree contains conflicted files; these "
128 	    "conflicts must be resolved first" },
129 	{ GOT_ERR_BRANCH_EXISTS,"specified branch already exists" },
130 	{ GOT_ERR_MODIFIED,	"work tree contains local changes; these "
131 	    "changes must be committed or reverted first" },
132 	{ GOT_ERR_NOT_REBASING,	"rebase operation not in progress" },
133 	{ GOT_ERR_REBASE_COMMITID,"rebase commit ID mismatch" },
134 	{ GOT_ERR_REBASING,	"a rebase operation is in progress in this "
135 	    "work tree and must be continued or aborted first" },
136 	{ GOT_ERR_REBASE_PATH,	"cannot rebase branch which contains "
137 	    "changes outside of this work tree's path prefix" },
138 	{ GOT_ERR_NOT_HISTEDIT,	"histedit operation not in progress" },
139 	{ GOT_ERR_EMPTY_HISTEDIT,"no commits to edit; perhaps the work tree "
140 	    "must be updated to an older commit first" },
141 	{ GOT_ERR_NO_HISTEDIT_CMD,"no histedit commands provided" },
142 	{ GOT_ERR_HISTEDIT_SYNTAX,"syntax error in histedit command list" },
143 	{ GOT_ERR_HISTEDIT_CANCEL,"histedit operation cancelled" },
144 	{ 95, "unused error code" },
145 	{ GOT_ERR_HISTEDIT_BUSY,"histedit operation is in progress in this "
146 	    "work tree and must be continued or aborted first" },
147 	{ GOT_ERR_HISTEDIT_CMD, "bad histedit command" },
148 	{ GOT_ERR_HISTEDIT_PATH, "cannot edit branch history which contains "
149 	    "changes outside of this work tree's path prefix" },
150 	{ GOT_ERR_PACKFILE_CSUM, "pack file checksum error" },
151 	{ GOT_ERR_COMMIT_BRANCH, "will not commit to a branch outside the "
152 	    "\"refs/heads/\" reference namespace" },
153 	{ GOT_ERR_FILE_STAGED, "file is staged" },
154 	{ GOT_ERR_STAGE_NO_CHANGE, "no changes to stage" },
155 	{ GOT_ERR_STAGE_CONFLICT, "cannot stage file in conflicted status" },
156 	{ GOT_ERR_STAGE_OUT_OF_DATE, "work tree must be updated before "
157 	    "changes can be staged" },
158 	{ GOT_ERR_FILE_NOT_STAGED, "file is not staged" },
159 	{ GOT_ERR_STAGED_PATHS, "work tree contains files with staged "
160 	    "changes; these changes must be committed or unstaged first" },
161 	{ GOT_ERR_PATCH_CHOICE, "invalid patch choice" },
162 	{ GOT_ERR_COMMIT_NO_EMAIL, "commit author's email address is required "
163 	    "for compatibility with Git" },
164 	{ GOT_ERR_TAG_EXISTS,"specified tag already exists" },
165 	{ GOT_ERR_GIT_REPO_FORMAT,"unknown git repository format version" },
166 	{ GOT_ERR_REBASE_REQUIRED,"specified branch must be rebased first" },
167 	{ GOT_ERR_REGEX, "regular expression error" },
168 	{ GOT_ERR_REF_NAME_MINUS, "reference name may not start with '-'" },
169 	{ GOT_ERR_GITCONFIG_SYNTAX, "gitconfig syntax error" },
170 	{ GOT_ERR_REBASE_OUT_OF_DATE, "work tree must be updated before it "
171 	    "can be used to rebase a branch" },
172 	{ GOT_ERR_CACHE_DUP_ENTRY, "duplicate cache entry" },
173 	{ GOT_ERR_FETCH_FAILED, "fetch failed" },
174 	{ GOT_ERR_PARSE_URI, "failed to parse uri" },
175 	{ GOT_ERR_BAD_PROTO, "unknown protocol" },
176 	{ GOT_ERR_ADDRINFO, "getaddrinfo failed" },
177 	{ GOT_ERR_BAD_PACKET, "bad packet received" },
178 	{ GOT_ERR_NO_REMOTE, "remote repository not found" },
179 	{ GOT_ERR_FETCH_NO_BRANCH, "could not find any branches to fetch" },
180 	{ GOT_ERR_FETCH_BAD_REF, "reference cannot be fetched" },
181 	{ GOT_ERR_TREE_ENTRY_TYPE, "unexpected tree entry type" },
182 	{ GOT_ERR_PARSE_CONFIG, "configuration file syntax error" },
183 	{ GOT_ERR_NO_CONFIG_FILE, "configuration file doesn't exit" },
184 	{ GOT_ERR_BAD_SYMLINK, "symbolic link points outside of paths under "
185 	    "version control" },
186 	{ GOT_ERR_GIT_REPO_EXT, "unsupported repository format extension" },
187 	{ GOT_ERR_CANNOT_PACK, "not enough objects to pack" },
188 	{ GOT_ERR_LONELY_PACKIDX, "pack index has no corresponding pack file; "
189 	    "pack file must be restored or 'gotadmin cleanup -p' must be run" },
190 	{ GOT_ERR_OBJ_CSUM, "bad object checksum" },
191 	{ GOT_ERR_SEND_BAD_REF, "reference cannot be sent" },
192 	{ GOT_ERR_SEND_FAILED, "could not send pack file" },
193 	{ GOT_ERR_SEND_EMPTY, "no references to send" },
194 	{ GOT_ERR_SEND_ANCESTRY, "fetch and rebase required" },
195 	{ GOT_ERR_CAPA_DELETE_REFS, "server cannot delete references" },
196 	{ GOT_ERR_SEND_DELETE_REF, "reference cannot be deleted" },
197 	{ GOT_ERR_SEND_TAG_EXISTS, "tag already exists on server" },
198 	{ GOT_ERR_NOT_MERGING,	"merge operation not in progress" },
199 	{ GOT_ERR_MERGE_OUT_OF_DATE, "work tree must be updated before it "
200 	    "can be used to merge a branch" },
201 	{ GOT_ERR_MERGE_STAGED_PATHS, "work tree contains files with staged "
202 	    "changes; these changes must be unstaged before merging can "
203 	    "proceed" },
204 	{ GOT_ERR_MERGE_BUSY,"a merge operation is in progress in this "
205 	    "work tree and must be continued or aborted first" },
206 	{ GOT_ERR_MERGE_PATH,	"cannot merge branch which contains "
207 	    "changes outside of this work tree's path prefix" },
208 	{ GOT_ERR_FILE_BINARY, "found a binary file instead of text" },
209 	{ GOT_ERR_PATCH_MALFORMED, "malformed patch" },
210 	{ GOT_ERR_PATCH_TRUNCATED, "patch truncated" },
211 	{ GOT_ERR_NO_PATCH, "no patch found" },
212 	{ GOT_ERR_HUNK_FAILED, "hunk failed to apply" },
213 	{ GOT_ERR_PATCH_FAILED, "patch failed to apply" },
214 	{ GOT_ERR_FILEIDX_DUP_ENTRY, "duplicate file index entry" },
215 	{ GOT_ERR_PIN_PACK, "could not pin pack file" },
216 	{ GOT_ERR_BAD_TAG_SIGNATURE, "invalid tag signature" },
217 	{ GOT_ERR_VERIFY_TAG_SIGNATURE, "cannot verify signature" },
218 	{ GOT_ERR_SIGNING_TAG, "unable to sign tag" },
219 	{ GOT_ERR_BAD_OPTION, "option cannot be used" },
220 	{ GOT_ERR_BAD_QUERYSTRING, "invalid query string" },
221 	{ GOT_ERR_INTEGRATE_BRANCH, "will not integrate into a reference "
222 	    "outside the \"refs/heads/\" reference namespace" },
223 	{ GOT_ERR_BAD_REQUEST, "unexpected request received" },
224 	{ GOT_ERR_CLIENT_ID, "unknown client identifier" },
225 	{ GOT_ERR_REPO_TEMPFILE, "no repository tempfile available" },
226 	{ GOT_ERR_REFS_PROTECTED, "reference namespace is protected" },
227 	{ GOT_ERR_REF_PROTECTED, "reference is protected" },
228 	{ GOT_ERR_REF_BUSY, "reference cannot be updated; please try again" },
229 	{ GOT_ERR_COMMIT_BAD_AUTHOR, "commit author formatting would "
230 	    "make Git unhappy" },
231 	{ GOT_ERR_UID, "bad user ID" },
232 	{ GOT_ERR_GID, "bad group ID" },
233 	{ GOT_ERR_NO_PROG, "command not found or not accessible" },
234 	{ GOT_ERR_MERGE_COMMIT_OUT_OF_DATE, "merging cannot proceed because "
235 	    "the work tree is no longer up-to-date; merge must be aborted "
236 	    "and retried" },
237 	{ GOT_ERR_BUNDLE_FORMAT, "unknown git bundle version" },
238 	{ GOT_ERR_BAD_KEYWORD, "invalid commit keyword" }
239 };
240 
241 static struct got_custom_error {
242 	struct got_error err;
243 	char msg[GOT_ERR_MAX_MSG_SIZE];
244 } custom_errors[16];
245 
246 static struct got_custom_error *
247 get_custom_err(void)
248 {
249 	static unsigned int idx;
250 	return &custom_errors[(idx++) % nitems(custom_errors)];
251 }
252 
253 const struct got_error *
254 got_error(int code)
255 {
256 	size_t i;
257 
258 	for (i = 0; i < nitems(got_errors); i++) {
259 		if (code == got_errors[i].code)
260 			return &got_errors[i];
261 	}
262 
263 	abort();
264 }
265 
266 const struct got_error *
267 got_error_msg(int code, const char *msg)
268 {
269 	struct got_custom_error *cerr = get_custom_err();
270 	struct got_error *err = &cerr->err;
271 	size_t i;
272 
273 	for (i = 0; i < nitems(got_errors); i++) {
274 		if (code == got_errors[i].code) {
275 			err->code = code;
276 			strlcpy(cerr->msg, msg, sizeof(cerr->msg));
277 			err->msg = cerr->msg;
278 			return err;
279 		}
280 	}
281 
282 	abort();
283 }
284 
285 const struct got_error *
286 got_error_from_errno(const char *prefix)
287 {
288 	struct got_custom_error *cerr = get_custom_err();
289 	struct got_error *err = &cerr->err;
290 	char strerr[128];
291 
292 	strerror_r(errno, strerr, sizeof(strerr));
293 	snprintf(cerr->msg, sizeof(cerr->msg), "%s: %s", prefix, strerr);
294 
295 	err->code = GOT_ERR_ERRNO;
296 	err->msg = cerr->msg;
297 	return err;
298 }
299 
300 const struct got_error *
301 got_error_from_errno2(const char *prefix, const char *prefix2)
302 {
303 	struct got_custom_error *cerr = get_custom_err();
304 	struct got_error *err = &cerr->err;
305 	char strerr[128];
306 
307 	strerror_r(errno, strerr, sizeof(strerr));
308 	snprintf(cerr->msg, sizeof(cerr->msg), "%s: %s: %s", prefix, prefix2,
309 	    strerr);
310 
311 	err->code = GOT_ERR_ERRNO;
312 	err->msg = cerr->msg;
313 	return err;
314 }
315 
316 const struct got_error *
317 got_error_from_errno3(const char *prefix, const char *prefix2,
318     const char *prefix3)
319 {
320 	struct got_custom_error *cerr = get_custom_err();
321 	struct got_error *err = &cerr->err;
322 	char strerr[128];
323 
324 	strerror_r(errno, strerr, sizeof(strerr));
325 	snprintf(cerr->msg, sizeof(cerr->msg), "%s: %s: %s: %s", prefix,
326 	    prefix2, prefix3, strerr);
327 
328 	err->code = GOT_ERR_ERRNO;
329 	err->msg = cerr->msg;
330 	return err;
331 }
332 
333 const struct got_error *
334 got_error_from_errno_fmt(const char *fmt, ...)
335 {
336 	struct got_custom_error *cerr = get_custom_err();
337 	struct got_error *err = &cerr->err;
338 	char buf[PATH_MAX * 4];
339 	char strerr[128];
340 	va_list ap;
341 
342 	va_start(ap, fmt);
343 	vsnprintf(buf, sizeof(buf), fmt, ap);
344 	va_end(ap);
345 
346 	strerror_r(errno, strerr, sizeof(strerr));
347 	snprintf(cerr->msg, sizeof(cerr->msg), "%s: %s", buf, strerr);
348 
349 	err->code = GOT_ERR_ERRNO;
350 	err->msg = cerr->msg;
351 	return err;
352 }
353 
354 const struct got_error *
355 got_error_set_errno(int code, const char *prefix)
356 {
357 	errno = code;
358 	return got_error_from_errno(prefix);
359 }
360 
361 const struct got_error *
362 got_ferror(FILE *f, int code)
363 {
364 	if (ferror(f))
365 		return got_error_from_errno("");
366 	return got_error(code);
367 }
368 
369 const struct got_error *
370 got_error_no_obj(struct got_object_id *id)
371 {
372 	char id_str[GOT_OBJECT_ID_HEX_MAXLEN];
373 	char msg[sizeof("object   not found") + sizeof(id_str)];
374 	int ret;
375 
376 	if (!got_object_id_hex(id, id_str, sizeof(id_str)))
377 		return got_error(GOT_ERR_NO_OBJ);
378 
379 	ret = snprintf(msg, sizeof(msg), "object %s not found", id_str);
380 	if (ret < 0 || (size_t)ret >= sizeof(msg))
381 		return got_error(GOT_ERR_NO_OBJ);
382 
383 	return got_error_msg(GOT_ERR_NO_OBJ, msg);
384 }
385 
386 const struct got_error *
387 got_error_checksum(struct got_object_id *id)
388 {
389 	char id_str[GOT_OBJECT_ID_HEX_MAXLEN];
390 	char msg[sizeof("checksum failure for object ") + sizeof(id_str)];
391 	int ret;
392 
393 	if (!got_object_id_hex(id, id_str, sizeof(id_str)))
394 		return got_error(GOT_ERR_OBJ_CSUM);
395 
396 	ret = snprintf(msg, sizeof(msg), "checksum failure for object %s",
397 	    id_str);
398 	if (ret < 0 || (size_t)ret >= sizeof(msg))
399 		return got_error(GOT_ERR_OBJ_CSUM);
400 
401 	return got_error_msg(GOT_ERR_OBJ_CSUM, msg);
402 }
403 
404 const struct got_error *
405 got_error_not_ref(const char *refname)
406 {
407 	char msg[sizeof("reference   not found") + 1004];
408 	int ret;
409 
410 	ret = snprintf(msg, sizeof(msg), "reference %s not found", refname);
411 	if (ret < 0 || (size_t)ret >= sizeof(msg))
412 		return got_error(GOT_ERR_NOT_REF);
413 
414 	return got_error_msg(GOT_ERR_NOT_REF, msg);
415 }
416 
417 const struct got_error *
418 got_error_uuid(uint32_t uuid_status, const char *prefix)
419 {
420 	switch (uuid_status) {
421 	case uuid_s_ok:
422 		return NULL;
423 	case uuid_s_bad_version:
424 		return got_error(GOT_ERR_UUID_VERSION);
425 	case uuid_s_invalid_string_uuid:
426 		return got_error(GOT_ERR_UUID_INVALID);
427 	case uuid_s_no_memory:
428 		return got_error_set_errno(ENOMEM, prefix);
429 	default:
430 		return got_error(GOT_ERR_UUID);
431 	}
432 }
433 
434 const struct got_error *
435 got_error_path(const char *path, int code)
436 {
437 	struct got_custom_error *cerr = get_custom_err();
438 	struct got_error *err = &cerr->err;
439 	size_t i;
440 
441 	for (i = 0; i < nitems(got_errors); i++) {
442 		if (code == got_errors[i].code) {
443 			err->code = code;
444 			snprintf(cerr->msg, sizeof(cerr->msg), "%s: %s", path,
445 			    got_errors[i].msg);
446 			err->msg = cerr->msg;
447 			return err;
448 		}
449 	}
450 
451 	abort();
452 }
453 
454 const struct got_error *
455 got_error_fmt(int code, const char *fmt, ...)
456 {
457 	struct got_custom_error *cerr = get_custom_err();
458 	struct got_error *err = &cerr->err;
459 	char buf[PATH_MAX * 4];
460 	va_list ap;
461 	size_t i;
462 
463 	va_start(ap, fmt);
464 	vsnprintf(buf, sizeof(buf), fmt, ap);
465 	va_end(ap);
466 
467 	for (i = 0; i < nitems(got_errors); i++) {
468 		if (code == got_errors[i].code) {
469 			err->code = code;
470 			snprintf(cerr->msg, sizeof(cerr->msg), "%s: %s", buf,
471 			    got_errors[i].msg);
472 			err->msg = cerr->msg;
473 			return err;
474 		}
475 	}
476 
477 	abort();
478 }
479 
480 int
481 got_err_open_nofollow_on_symlink(void)
482 {
483 	/*
484 	 * Check whether open(2) with O_NOFOLLOW failed on a symlink.
485 	 * Posix mandates ELOOP and OpenBSD follows it. Others return
486 	 * different error codes. We carry this workaround to help the
487 	 * portable version a little.
488 	 */
489 	return (errno == ELOOP
490 #ifdef EMLINK
491 	|| errno == EMLINK
492 #endif
493 #ifdef EFTYPE
494 	|| errno == EFTYPE
495 #endif
496 	);
497 }