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_object_parse.h"
37 
38 #ifndef nitems
39 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
40 #endif
41 
42 static const struct got_error got_errors[] = {
43 	{ GOT_ERR_OK,		"no error occured?!?" },
44 	{ GOT_ERR_ERRNO,	"see errno" },
45 	{ GOT_ERR_NOT_GIT_REPO, "no git repository found" },
46 	{ GOT_ERR_BAD_FILETYPE,	"bad file type" },
47 	{ GOT_ERR_BAD_PATH,	"bad path" },
48 	{ GOT_ERR_NOT_REF,	"no such reference found" },
49 	{ GOT_ERR_IO,		"input/output error" },
50 	{ GOT_ERR_EOF,		"unexpected end of file" },
51 	{ GOT_ERR_DECOMPRESSION,"decompression failed" },
52 	{ GOT_ERR_NO_SPACE,	"buffer too small" },
53 	{ GOT_ERR_BAD_OBJ_HDR,	"bad object header" },
54 	{ GOT_ERR_OBJ_TYPE,	"wrong type of object" },
55 	{ GOT_ERR_BAD_OBJ_DATA,	"bad object data" },
56 	{ GOT_ERR_AMBIGUOUS_ID, "ambiguous object ID" },
57 	{ GOT_ERR_BAD_PACKIDX,	"bad pack index file" },
58 	{ GOT_ERR_PACKIDX_CSUM, "pack index file checksum error" },
59 	{ GOT_ERR_BAD_PACKFILE,	"bad pack file" },
60 	{ GOT_ERR_NO_OBJ,	"object not found" },
61 	{ GOT_ERR_NOT_IMPL,	"feature not implemented" },
62 	{ GOT_ERR_OBJ_NOT_PACKED,"object is not packed" },
63 	{ GOT_ERR_BAD_DELTA_CHAIN,"bad delta chain" },
64 	{ GOT_ERR_BAD_DELTA,	"bad delta" },
65 	{ GOT_ERR_COMPRESSION,	"compression failed" },
66 	{ GOT_ERR_BAD_OBJ_ID_STR,"bad object id string" },
67 	{ GOT_ERR_WORKTREE_EXISTS,"worktree already exists" },
68 	{ GOT_ERR_WORKTREE_META,"bad worktree meta data" },
69 	{ GOT_ERR_WORKTREE_VERS,"unsupported worktree format version" },
70 	{ GOT_ERR_WORKTREE_BUSY,"worktree already locked" },
71 	{ GOT_ERR_FILE_OBSTRUCTED,"file is obstructed" },
72 	{ GOT_ERR_RECURSION,	"recursion limit reached" },
73 	{ GOT_ERR_TIMEOUT,	"operation timed out" },
74 	{ GOT_ERR_INTERRUPT,	"operation interrupted" },
75 	{ GOT_ERR_PRIVSEP_READ,	"no data received in imsg" },
76 	{ GOT_ERR_PRIVSEP_LEN,	"unexpected amount of data received in imsg" },
77 	{ GOT_ERR_PRIVSEP_PIPE,	"privsep peer process closed pipe" },
78 	{ GOT_ERR_PRIVSEP_NO_FD,"privsep file descriptor unavailable" },
79 	{ GOT_ERR_PRIVSEP_MSG,	"received unexpected privsep message" },
80 	{ GOT_ERR_PRIVSEP_DIED,	"unprivileged process died unexpectedly" },
81 	{ GOT_ERR_PRIVSEP_EXIT,	"bad exit code from unprivileged process" },
82 	{ GOT_ERR_PACK_OFFSET,	"bad offset in pack file" },
83 	{ GOT_ERR_OBJ_EXISTS,	"object already exists" },
84 	{ GOT_ERR_BAD_OBJ_ID,	"bad object id" },
85 	{ GOT_ERR_ITER_BUSY,	"iteration already in progress" },
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 got 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_QUERYSTRING, "bad querystring" },
174 	{ GOT_ERR_FETCH_FAILED, "fetch failed" },
175 	{ GOT_ERR_PARSE_URI, "failed to parse uri" },
176 	{ GOT_ERR_BAD_PROTO, "unknown protocol" },
177 	{ GOT_ERR_ADDRINFO, "getaddrinfo failed" },
178 	{ GOT_ERR_BAD_PACKET, "bad packet received" },
179 	{ GOT_ERR_NO_REMOTE, "remote repository not found" },
180 	{ GOT_ERR_FETCH_NO_BRANCH, "could not find any branches to fetch" },
181 	{ GOT_ERR_FETCH_BAD_REF, "reference cannot be fetched" },
182 	{ GOT_ERR_TREE_ENTRY_TYPE, "unexpected tree entry type" },
183 	{ GOT_ERR_PARSE_CONFIG, "configuration file syntax error" },
184 	{ GOT_ERR_NO_CONFIG_FILE, "configuration file doesn't exit" },
185 	{ GOT_ERR_BAD_SYMLINK, "symbolic link points outside of paths under "
186 	    "version control" },
187 	{ GOT_ERR_GIT_REPO_EXT, "unsupported repository format extension" },
188 	{ GOT_ERR_CANNOT_PACK, "not enough objects to pack" },
189 	{ GOT_ERR_LONELY_PACKIDX, "pack index has no corresponding pack file; "
190 	    "pack file must be restored or 'gotadmin cleanup -p' must be run" },
191 	{ GOT_ERR_OBJ_CSUM, "bad object checksum" },
192 	{ GOT_ERR_SEND_BAD_REF, "reference cannot be sent" },
193 	{ GOT_ERR_SEND_FAILED, "could not send pack file" },
194 	{ GOT_ERR_SEND_EMPTY, "no references to send" },
195 	{ GOT_ERR_SEND_ANCESTRY, "fetch and rebase required" },
196 	{ GOT_ERR_CAPA_DELETE_REFS, "server cannot delete references" },
197 	{ GOT_ERR_SEND_DELETE_REF, "reference cannot be deleted" },
198 	{ GOT_ERR_SEND_TAG_EXISTS, "tag already exists on server" },
199 	{ GOT_ERR_NOT_MERGING,	"merge operation not in progress" },
200 	{ GOT_ERR_MERGE_OUT_OF_DATE, "work tree must be updated before it "
201 	    "can be used to merge a branch" },
202 	{ GOT_ERR_MERGE_STAGED_PATHS, "work tree contains files with staged "
203 	    "changes; these changes must be unstaged before merging can "
204 	    "proceed" },
205 	{ GOT_ERR_MERGE_COMMIT_OUT_OF_DATE, "merging cannot proceed because "
206 	    "the work tree is no longer up-to-date; merge must be aborted "
207 	    "and retried" },
208 	{ GOT_ERR_MERGE_BUSY,"a merge operation is in progress in this "
209 	    "work tree and must be continued or aborted first" },
210 	{ GOT_ERR_MERGE_PATH,	"cannot merge branch which contains "
211 	    "changes outside of this work tree's path prefix" },
212 	{ GOT_ERR_FILE_BINARY, "found a binary file instead of text" },
213 	{ GOT_ERR_PATCH_MALFORMED, "malformed patch" },
214 	{ GOT_ERR_PATCH_TRUNCATED, "patch truncated" },
215 	{ GOT_ERR_NO_PATCH, "no patch found" },
216 	{ GOT_ERR_HUNK_FAILED, "hunk failed to apply" },
217 	{ GOT_ERR_PATCH_FAILED, "patch failed to apply" },
218 	{ GOT_ERR_FILEIDX_DUP_ENTRY, "duplicate file index entry" },
219 	{ GOT_ERR_PIN_PACK, "could not pin pack file" },
220 	{ GOT_ERR_BAD_TAG_SIGNATURE, "invalid tag signature" },
221 	{ GOT_ERR_VERIFY_TAG_SIGNATURE, "cannot verify signature" },
222 	{ GOT_ERR_SIGNING_TAG, "unable to sign tag" },
223 	{ GOT_ERR_BAD_QUERYSTRING, "invalid query string" },
224 	{ GOT_ERR_INTEGRATE_BRANCH, "will not integrate into a reference "
225 	    "outside the \"refs/heads/\" reference namespace" },
226 	{ GOT_ERR_BAD_REQUEST, "unexpected request received" },
227 	{ GOT_ERR_CLIENT_ID, "unknown client identifier" },
228 	{ GOT_ERR_REPO_TEMPFILE, "no repository tempfile available" },
229 	{ GOT_ERR_REFS_PROTECTED, "reference namespace may not be modified" },
230 	{ GOT_ERR_REF_PROTECTED," reference may not be modified" },
231 	{ GOT_ERR_REF_BUSY, "reference cannot be updated; please try again" },
232 	{ GOT_ERR_COMMIT_BAD_AUTHOR, "commit author formatting would "
233 	    "make Git unhappy" },
234 	{ GOT_ERR_UID, "bad user ID" },
235 	{ GOT_ERR_GID, "bad group ID" },
236 };
237 
238 static struct got_custom_error {
239 	struct got_error err;
240 	char msg[GOT_ERR_MAX_MSG_SIZE];
241 } custom_errors[16];
242 
243 static struct got_custom_error *
244 get_custom_err(void)
245 {
246 	static unsigned int idx;
247 	return &custom_errors[(idx++) % nitems(custom_errors)];
248 }
249 
250 const struct got_error *
251 got_error(int code)
252 {
253 	size_t i;
254 
255 	for (i = 0; i < nitems(got_errors); i++) {
256 		if (code == got_errors[i].code)
257 			return &got_errors[i];
258 	}
259 
260 	abort();
261 }
262 
263 const struct got_error *
264 got_error_msg(int code, const char *msg)
265 {
266 	struct got_custom_error *cerr = get_custom_err();
267 	struct got_error *err = &cerr->err;
268 	size_t i;
269 
270 	for (i = 0; i < nitems(got_errors); i++) {
271 		if (code == got_errors[i].code) {
272 			err->code = code;
273 			strlcpy(cerr->msg, msg, sizeof(cerr->msg));
274 			err->msg = cerr->msg;
275 			return err;
276 		}
277 	}
278 
279 	abort();
280 }
281 
282 const struct got_error *
283 got_error_from_errno(const char *prefix)
284 {
285 	struct got_custom_error *cerr = get_custom_err();
286 	struct got_error *err = &cerr->err;
287 	char strerr[128];
288 
289 	strerror_r(errno, strerr, sizeof(strerr));
290 	snprintf(cerr->msg, sizeof(cerr->msg), "%s: %s", prefix, strerr);
291 
292 	err->code = GOT_ERR_ERRNO;
293 	err->msg = cerr->msg;
294 	return err;
295 }
296 
297 const struct got_error *
298 got_error_from_errno2(const char *prefix, const char *prefix2)
299 {
300 	struct got_custom_error *cerr = get_custom_err();
301 	struct got_error *err = &cerr->err;
302 	char strerr[128];
303 
304 	strerror_r(errno, strerr, sizeof(strerr));
305 	snprintf(cerr->msg, sizeof(cerr->msg), "%s: %s: %s", prefix, prefix2,
306 	    strerr);
307 
308 	err->code = GOT_ERR_ERRNO;
309 	err->msg = cerr->msg;
310 	return err;
311 }
312 
313 const struct got_error *
314 got_error_from_errno3(const char *prefix, const char *prefix2,
315     const char *prefix3)
316 {
317 	struct got_custom_error *cerr = get_custom_err();
318 	struct got_error *err = &cerr->err;
319 	char strerr[128];
320 
321 	strerror_r(errno, strerr, sizeof(strerr));
322 	snprintf(cerr->msg, sizeof(cerr->msg), "%s: %s: %s: %s", prefix,
323 	    prefix2, prefix3, strerr);
324 
325 	err->code = GOT_ERR_ERRNO;
326 	err->msg = cerr->msg;
327 	return err;
328 }
329 
330 const struct got_error *
331 got_error_from_errno_fmt(const char *fmt, ...)
332 {
333 	struct got_custom_error *cerr = get_custom_err();
334 	struct got_error *err = &cerr->err;
335 	char buf[PATH_MAX * 4];
336 	char strerr[128];
337 	va_list ap;
338 
339 	va_start(ap, fmt);
340 	vsnprintf(buf, sizeof(buf), fmt, ap);
341 	va_end(ap);
342 
343 	strerror_r(errno, strerr, sizeof(strerr));
344 	snprintf(cerr->msg, sizeof(cerr->msg), "%s: %s", buf, strerr);
345 
346 	err->code = GOT_ERR_ERRNO;
347 	err->msg = cerr->msg;
348 	return err;
349 }
350 
351 const struct got_error *
352 got_error_set_errno(int code, const char *prefix)
353 {
354 	errno = code;
355 	return got_error_from_errno(prefix);
356 }
357 
358 const struct got_error *
359 got_ferror(FILE *f, int code)
360 {
361 	if (ferror(f))
362 		return got_error_from_errno("");
363 	return got_error(code);
364 }
365 
366 const struct got_error *
367 got_error_no_obj(struct got_object_id *id)
368 {
369 	char id_str[GOT_OBJECT_ID_HEX_MAXLEN];
370 	char msg[sizeof("object   not found") + sizeof(id_str)];
371 	int ret;
372 
373 	if (!got_object_id_hex(id, id_str, sizeof(id_str)))
374 		return got_error(GOT_ERR_NO_OBJ);
375 
376 	ret = snprintf(msg, sizeof(msg), "object %s not found", id_str);
377 	if (ret < 0 || (size_t)ret >= sizeof(msg))
378 		return got_error(GOT_ERR_NO_OBJ);
379 
380 	return got_error_msg(GOT_ERR_NO_OBJ, msg);
381 }
382 
383 const struct got_error *
384 got_error_checksum(struct got_object_id *id)
385 {
386 	char id_str[GOT_OBJECT_ID_HEX_MAXLEN];
387 	char msg[sizeof("checksum failure for object ") + sizeof(id_str)];
388 	int ret;
389 
390 	if (!got_object_id_hex(id, id_str, sizeof(id_str)))
391 		return got_error(GOT_ERR_OBJ_CSUM);
392 
393 	ret = snprintf(msg, sizeof(msg), "checksum failure for object %s",
394 	    id_str);
395 	if (ret < 0 || (size_t)ret >= sizeof(msg))
396 		return got_error(GOT_ERR_OBJ_CSUM);
397 
398 	return got_error_msg(GOT_ERR_OBJ_CSUM, msg);
399 }
400 
401 const struct got_error *
402 got_error_not_ref(const char *refname)
403 {
404 	char msg[sizeof("reference   not found") + 1004];
405 	int ret;
406 
407 	ret = snprintf(msg, sizeof(msg), "reference %s not found", refname);
408 	if (ret < 0 || (size_t)ret >= sizeof(msg))
409 		return got_error(GOT_ERR_NOT_REF);
410 
411 	return got_error_msg(GOT_ERR_NOT_REF, msg);
412 }
413 
414 const struct got_error *
415 got_error_uuid(uint32_t uuid_status, const char *prefix)
416 {
417 	switch (uuid_status) {
418 	case uuid_s_ok:
419 		return NULL;
420 	case uuid_s_bad_version:
421 		return got_error(GOT_ERR_UUID_VERSION);
422 	case uuid_s_invalid_string_uuid:
423 		return got_error(GOT_ERR_UUID_INVALID);
424 	case uuid_s_no_memory:
425 		return got_error_set_errno(ENOMEM, prefix);
426 	default:
427 		return got_error(GOT_ERR_UUID);
428 	}
429 }
430 
431 const struct got_error *
432 got_error_path(const char *path, int code)
433 {
434 	struct got_custom_error *cerr = get_custom_err();
435 	struct got_error *err = &cerr->err;
436 	size_t i;
437 
438 	for (i = 0; i < nitems(got_errors); i++) {
439 		if (code == got_errors[i].code) {
440 			err->code = code;
441 			snprintf(cerr->msg, sizeof(cerr->msg), "%s: %s", path,
442 			    got_errors[i].msg);
443 			err->msg = cerr->msg;
444 			return err;
445 		}
446 	}
447 
448 	abort();
449 }
450 
451 const struct got_error *
452 got_error_fmt(int code, const char *fmt, ...)
453 {
454 	struct got_custom_error *cerr = get_custom_err();
455 	struct got_error *err = &cerr->err;
456 	char buf[PATH_MAX * 4];
457 	va_list ap;
458 	size_t i;
459 
460 	va_start(ap, fmt);
461 	vsnprintf(buf, sizeof(buf), fmt, ap);
462 	va_end(ap);
463 
464 	for (i = 0; i < nitems(got_errors); i++) {
465 		if (code == got_errors[i].code) {
466 			err->code = code;
467 			snprintf(cerr->msg, sizeof(cerr->msg), "%s: %s", buf,
468 			    got_errors[i].msg);
469 			err->msg = cerr->msg;
470 			return err;
471 		}
472 	}
473 
474 	abort();
475 }
476 
477 int
478 got_err_open_nofollow_on_symlink(void)
479 {
480 	/*
481 	 * Check whether open(2) with O_NOFOLLOW failed on a symlink.
482 	 * Posix mandates ELOOP and OpenBSD follows it. Others return
483 	 * different error codes. We carry this workaround to help the
484 	 * portable version a little.
485 	 */
486 	return (errno == ELOOP
487 #ifdef EMLINK
488 	|| errno == EMLINK
489 #endif
490 #ifdef EFTYPE
491 	|| errno == EFTYPE
492 #endif
493 	);
494 }