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 <zlib.h>
26 
27 #include "got_compat.h"
28 
29 #include "got_error.h"
30 #include "got_object.h"
31 
32 #include "got_lib_delta.h"
33 #include "got_lib_inflate.h"
34 #include "got_lib_object.h"
35 #include "got_lib_hash.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 #if defined(__GLIBC__)
43 	/*
44 	 * The autoconf test for strerror_r is broken in current versions
45 	 * of autoconf: https://savannah.gnu.org/support/?110367
46 	 */
47 char *__xpg_strerror_r(int, char *, size_t);
48 #define strerror_r __xpg_strerror_r
49 #endif
50 
51 static const struct got_error got_errors[] = {
52 	{ GOT_ERR_OK,		"no error occured?!?" },
53 	{ GOT_ERR_ERRNO,	"see errno" },
54 	{ GOT_ERR_NOT_GIT_REPO, "no git repository found" },
55 	{ GOT_ERR_BAD_FILETYPE,	"bad file type" },
56 	{ GOT_ERR_BAD_PATH,	"bad path" },
57 	{ GOT_ERR_NOT_REF,	"no such reference found" },
58 	{ GOT_ERR_IO,		"input/output error" },
59 	{ GOT_ERR_EOF,		"unexpected end of file" },
60 	{ GOT_ERR_DECOMPRESSION,"decompression failed" },
61 	{ GOT_ERR_NO_SPACE,	"buffer too small" },
62 	{ GOT_ERR_BAD_OBJ_HDR,	"bad object header" },
63 	{ GOT_ERR_OBJ_TYPE,	"wrong type of object" },
64 	{ GOT_ERR_BAD_OBJ_DATA,	"bad object data" },
65 	{ GOT_ERR_AMBIGUOUS_ID, "ambiguous object ID" },
66 	{ GOT_ERR_BAD_PACKIDX,	"bad pack index file" },
67 	{ GOT_ERR_PACKIDX_CSUM, "pack index file checksum error" },
68 	{ GOT_ERR_BAD_PACKFILE,	"bad pack file" },
69 	{ GOT_ERR_NO_OBJ,	"object not found" },
70 	{ GOT_ERR_NOT_IMPL,	"feature not implemented" },
71 	{ GOT_ERR_OBJ_NOT_PACKED,"object is not packed" },
72 	{ GOT_ERR_BAD_DELTA_CHAIN,"bad delta chain" },
73 	{ GOT_ERR_BAD_DELTA,	"bad delta" },
74 	{ GOT_ERR_COMPRESSION,	"compression failed" },
75 	{ GOT_ERR_BAD_OBJ_ID_STR,"bad object id string" },
76 	{ GOT_ERR_WORKTREE_EXISTS,"worktree already exists" },
77 	{ GOT_ERR_WORKTREE_META,"bad worktree meta data" },
78 	{ GOT_ERR_WORKTREE_VERS,"unsupported worktree format version" },
79 	{ GOT_ERR_WORKTREE_BUSY,"worktree already locked" },
80 	{ GOT_ERR_FILE_OBSTRUCTED,"file is obstructed" },
81 	{ GOT_ERR_RECURSION,	"recursion limit reached" },
82 	{ GOT_ERR_TIMEOUT,	"operation timed out" },
83 	{ GOT_ERR_INTERRUPT,	"operation interrupted" },
84 	{ GOT_ERR_PRIVSEP_READ,	"no data received in imsg" },
85 	{ GOT_ERR_PRIVSEP_LEN,	"unexpected amount of data received in imsg" },
86 	{ GOT_ERR_PRIVSEP_PIPE,	"privsep peer process closed pipe" },
87 	{ GOT_ERR_PRIVSEP_NO_FD,"privsep file descriptor unavailable" },
88 	{ GOT_ERR_PRIVSEP_MSG,	"received unexpected privsep message" },
89 	{ GOT_ERR_PRIVSEP_DIED,	"unprivileged process died unexpectedly" },
90 	{ GOT_ERR_PRIVSEP_EXIT,	"bad exit code from unprivileged process" },
91 	{ GOT_ERR_PACK_OFFSET,	"bad offset in pack file" },
92 	{ GOT_ERR_OBJ_EXISTS,	"object already exists" },
93 	{ GOT_ERR_BAD_OBJ_ID,	"bad object id" },
94 	{ GOT_ERR_ITER_BUSY,	"iteration already in progress" },
95 	{ GOT_ERR_ITER_COMPLETED,"iteration completed" },
96 	{ GOT_ERR_RANGE,	"value out of range" },
97 	{ GOT_ERR_EXPECTED,	"expected an error but have no error" },
98 	{ GOT_ERR_CANCELLED,	"operation in progress has been cancelled" },
99 	{ GOT_ERR_NO_TREE_ENTRY,"no such entry found in tree" },
100 	{ GOT_ERR_FILEIDX_SIG,	"bad file index signature" },
101 	{ GOT_ERR_FILEIDX_VER,	"unknown file index format version" },
102 	{ GOT_ERR_FILEIDX_CSUM,	"bad file index checksum" },
103 	{ GOT_ERR_PATH_PREFIX,	"worktree already contains items from a "
104 				"different path prefix" },
105 	{ GOT_ERR_ANCESTRY,	"target commit is on a different branch" },
106 	{ GOT_ERR_FILEIDX_BAD,	"file index is corrupt" },
107 	{ GOT_ERR_BAD_REF_DATA,	"could not parse reference data" },
108 	{ GOT_ERR_TREE_DUP_ENTRY,"duplicate entry in tree object" },
109 	{ GOT_ERR_DIR_DUP_ENTRY,"duplicate entry in directory" },
110 	{ GOT_ERR_NOT_WORKTREE, "no work tree found" },
111 	{ GOT_ERR_UUID_VERSION, "bad uuid version" },
112 	{ GOT_ERR_UUID_INVALID, "uuid invalid" },
113 	{ GOT_ERR_UUID,		"uuid error" },
114 	{ GOT_ERR_LOCKFILE_TIMEOUT,"lockfile timeout" },
115 	{ GOT_ERR_BAD_REF_NAME,	"bad reference name" },
116 	{ GOT_ERR_WORKTREE_REPO,"cannot create worktree inside a git repository" },
117 	{ GOT_ERR_FILE_MODIFIED,"file contains modifications" },
118 	{ GOT_ERR_FILE_STATUS,	"file has unexpected status" },
119 	{ GOT_ERR_COMMIT_CONFLICT,"cannot commit file in conflicted status" },
120 	{ GOT_ERR_BAD_REF_TYPE,	"bad reference type" },
121 	{ GOT_ERR_COMMIT_NO_AUTHOR,"GOT_AUTHOR environment variable is not set" },
122 	{ GOT_ERR_COMMIT_HEAD_CHANGED, "branch head in repository has changed "
123 	    "while commit was in progress" },
124 	{ GOT_ERR_COMMIT_OUT_OF_DATE, "work tree must be updated before these "
125 	    "changes can be committed" },
126 	{ GOT_ERR_COMMIT_MSG_EMPTY, "commit message cannot be empty" },
127 	{ GOT_ERR_DIR_NOT_EMPTY, "directory exists and is not empty" },
128 	{ GOT_ERR_COMMIT_NO_CHANGES, "no changes to commit" },
129 	{ GOT_ERR_BRANCH_MOVED,	"work tree's head reference now points to a "
130 	    "different branch; new head reference and/or update -b required" },
131 	{ GOT_ERR_OBJ_TOO_LARGE,	"object too large" },
132 	{ GOT_ERR_SAME_BRANCH,	"commit is already contained in this branch" },
133 	{ GOT_ERR_ROOT_COMMIT,	"specified commit has no parent commit" },
134 	{ GOT_ERR_MIXED_COMMITS,"work tree contains files from multiple "
135 	    "base commits; the entire work tree must be updated first" },
136 	{ GOT_ERR_CONFLICTS,	"work tree contains conflicted files; these "
137 	    "conflicts must be resolved first" },
138 	{ GOT_ERR_BRANCH_EXISTS,"specified branch already exists" },
139 	{ GOT_ERR_MODIFIED,	"work tree contains local changes; these "
140 	    "changes must be committed or reverted first" },
141 	{ GOT_ERR_NOT_REBASING,	"rebase operation not in progress" },
142 	{ GOT_ERR_REBASE_COMMITID,"rebase commit ID mismatch" },
143 	{ GOT_ERR_REBASING,	"a rebase operation is in progress in this "
144 	    "work tree and must be continued or aborted first" },
145 	{ GOT_ERR_REBASE_PATH,	"cannot rebase branch which contains "
146 	    "changes outside of this work tree's path prefix" },
147 	{ GOT_ERR_NOT_HISTEDIT,	"histedit operation not in progress" },
148 	{ GOT_ERR_EMPTY_HISTEDIT,"no commits to edit; perhaps the work tree "
149 	    "must be updated to an older commit first" },
150 	{ GOT_ERR_NO_HISTEDIT_CMD,"no histedit commands provided" },
151 	{ GOT_ERR_HISTEDIT_SYNTAX,"syntax error in histedit command list" },
152 	{ GOT_ERR_HISTEDIT_CANCEL,"histedit operation cancelled" },
153 	{ 95, "unused error code" },
154 	{ GOT_ERR_HISTEDIT_BUSY,"histedit operation is in progress in this "
155 	    "work tree and must be continued or aborted first" },
156 	{ GOT_ERR_HISTEDIT_CMD, "bad histedit command" },
157 	{ GOT_ERR_HISTEDIT_PATH, "cannot edit branch history which contains "
158 	    "changes outside of this work tree's path prefix" },
159 	{ GOT_ERR_PACKFILE_CSUM, "pack file checksum error" },
160 	{ GOT_ERR_COMMIT_BRANCH, "will not commit to a branch outside the "
161 	    "\"refs/heads/\" reference namespace" },
162 	{ GOT_ERR_FILE_STAGED, "file is staged" },
163 	{ GOT_ERR_STAGE_NO_CHANGE, "no changes to stage" },
164 	{ GOT_ERR_STAGE_CONFLICT, "cannot stage file in conflicted status" },
165 	{ GOT_ERR_STAGE_OUT_OF_DATE, "work tree must be updated before "
166 	    "changes can be staged" },
167 	{ GOT_ERR_FILE_NOT_STAGED, "file is not staged" },
168 	{ GOT_ERR_STAGED_PATHS, "work tree contains files with staged "
169 	    "changes; these changes must be committed or unstaged first" },
170 	{ GOT_ERR_PATCH_CHOICE, "invalid patch choice" },
171 	{ GOT_ERR_COMMIT_NO_EMAIL, "commit author's email address is required "
172 	    "for compatibility with Git" },
173 	{ GOT_ERR_TAG_EXISTS,"specified tag already exists" },
174 	{ GOT_ERR_GIT_REPO_FORMAT,"unknown git repository format version" },
175 	{ GOT_ERR_REBASE_REQUIRED,"specified branch must be rebased first" },
176 	{ GOT_ERR_REGEX, "regular expression error" },
177 	{ GOT_ERR_REF_NAME_MINUS, "reference name may not start with '-'" },
178 	{ GOT_ERR_GITCONFIG_SYNTAX, "gitconfig syntax error" },
179 	{ GOT_ERR_REBASE_OUT_OF_DATE, "work tree must be updated before it "
180 	    "can be used to rebase a branch" },
181 	{ GOT_ERR_CACHE_DUP_ENTRY, "duplicate cache entry" },
182 	{ GOT_ERR_FETCH_FAILED, "fetch failed" },
183 	{ GOT_ERR_PARSE_URI, "failed to parse uri" },
184 	{ GOT_ERR_BAD_PROTO, "unknown protocol" },
185 	{ GOT_ERR_ADDRINFO, "getaddrinfo failed" },
186 	{ GOT_ERR_BAD_PACKET, "bad packet received" },
187 	{ GOT_ERR_NO_REMOTE, "remote repository not found" },
188 	{ GOT_ERR_FETCH_NO_BRANCH, "could not find any branches to fetch" },
189 	{ GOT_ERR_FETCH_BAD_REF, "reference cannot be fetched" },
190 	{ GOT_ERR_TREE_ENTRY_TYPE, "unexpected tree entry type" },
191 	{ GOT_ERR_PARSE_CONFIG, "configuration file syntax error" },
192 	{ GOT_ERR_NO_CONFIG_FILE, "configuration file doesn't exit" },
193 	{ GOT_ERR_BAD_SYMLINK, "symbolic link points outside of paths under "
194 	    "version control" },
195 	{ GOT_ERR_GIT_REPO_EXT, "unsupported repository format extension" },
196 	{ GOT_ERR_CANNOT_PACK, "not enough objects to pack" },
197 	{ GOT_ERR_LONELY_PACKIDX, "pack index has no corresponding pack file; "
198 	    "pack file must be restored or 'gotadmin cleanup -p' must be run" },
199 	{ GOT_ERR_OBJ_CSUM, "bad object checksum" },
200 	{ GOT_ERR_SEND_BAD_REF, "reference cannot be sent" },
201 	{ GOT_ERR_SEND_FAILED, "could not send pack file" },
202 	{ GOT_ERR_SEND_EMPTY, "no references to send" },
203 	{ GOT_ERR_SEND_ANCESTRY, "fetch and rebase required" },
204 	{ GOT_ERR_CAPA_DELETE_REFS, "server cannot delete references" },
205 	{ GOT_ERR_SEND_DELETE_REF, "reference cannot be deleted" },
206 	{ GOT_ERR_SEND_TAG_EXISTS, "tag already exists on server" },
207 	{ GOT_ERR_NOT_MERGING,	"merge operation not in progress" },
208 	{ GOT_ERR_MERGE_OUT_OF_DATE, "work tree must be updated before it "
209 	    "can be used to merge a branch" },
210 	{ GOT_ERR_MERGE_STAGED_PATHS, "work tree contains files with staged "
211 	    "changes; these changes must be unstaged before merging can "
212 	    "proceed" },
213 	{ GOT_ERR_MERGE_BUSY,"a merge operation is in progress in this "
214 	    "work tree and must be continued or aborted first" },
215 	{ GOT_ERR_MERGE_PATH,	"cannot merge branch which contains "
216 	    "changes outside of this work tree's path prefix" },
217 	{ GOT_ERR_FILE_BINARY, "found a binary file instead of text" },
218 	{ GOT_ERR_PATCH_MALFORMED, "malformed patch" },
219 	{ GOT_ERR_PATCH_TRUNCATED, "patch truncated" },
220 	{ GOT_ERR_NO_PATCH, "no patch found" },
221 	{ GOT_ERR_HUNK_FAILED, "hunk failed to apply" },
222 	{ GOT_ERR_PATCH_FAILED, "patch failed to apply" },
223 	{ GOT_ERR_FILEIDX_DUP_ENTRY, "duplicate file index entry" },
224 	{ GOT_ERR_PIN_PACK, "could not pin pack file" },
225 	{ GOT_ERR_BAD_TAG_SIGNATURE, "invalid tag signature" },
226 	{ GOT_ERR_VERIFY_TAG_SIGNATURE, "cannot verify signature" },
227 	{ GOT_ERR_SIGNING_TAG, "unable to sign tag" },
228 	{ GOT_ERR_BAD_OPTION, "option cannot be used" },
229 	{ GOT_ERR_BAD_QUERYSTRING, "invalid query string" },
230 	{ GOT_ERR_INTEGRATE_BRANCH, "will not integrate into a reference "
231 	    "outside the \"refs/heads/\" reference namespace" },
232 	{ GOT_ERR_BAD_REQUEST, "unexpected request received" },
233 	{ GOT_ERR_CLIENT_ID, "unknown client identifier" },
234 	{ GOT_ERR_REPO_TEMPFILE, "no repository tempfile available" },
235 	{ GOT_ERR_REFS_PROTECTED, "reference namespace is protected" },
236 	{ GOT_ERR_REF_PROTECTED, "reference is protected" },
237 	{ GOT_ERR_REF_BUSY, "reference cannot be updated; please try again" },
238 	{ GOT_ERR_COMMIT_BAD_AUTHOR, "commit author formatting would "
239 	    "make Git unhappy" },
240 	{ GOT_ERR_UID, "bad user ID" },
241 	{ GOT_ERR_GID, "bad group ID" },
242 	{ GOT_ERR_NO_PROG, "command not found or not accessible" },
243 	{ GOT_ERR_MERGE_COMMIT_OUT_OF_DATE, "merging cannot proceed because "
244 	    "the work tree is no longer up-to-date; merge must be aborted "
245 	    "and retried" },
246 	{ GOT_ERR_BUNDLE_FORMAT, "unknown git bundle version" },
247 	{ GOT_ERR_BAD_KEYWORD, "invalid commit keyword" }
248 };
249 
250 static struct got_custom_error {
251 	struct got_error err;
252 	char msg[GOT_ERR_MAX_MSG_SIZE];
253 } custom_errors[16];
254 
255 static struct got_custom_error *
256 get_custom_err(void)
257 {
258 	static unsigned int idx;
259 	return &custom_errors[(idx++) % nitems(custom_errors)];
260 }
261 
262 const struct got_error *
263 got_error(int code)
264 {
265 	size_t i;
266 
267 	for (i = 0; i < nitems(got_errors); i++) {
268 		if (code == got_errors[i].code)
269 			return &got_errors[i];
270 	}
271 
272 	abort();
273 }
274 
275 const struct got_error *
276 got_error_msg(int code, const char *msg)
277 {
278 	struct got_custom_error *cerr = get_custom_err();
279 	struct got_error *err = &cerr->err;
280 	size_t i;
281 
282 	for (i = 0; i < nitems(got_errors); i++) {
283 		if (code == got_errors[i].code) {
284 			err->code = code;
285 			strlcpy(cerr->msg, msg, sizeof(cerr->msg));
286 			err->msg = cerr->msg;
287 			return err;
288 		}
289 	}
290 
291 	abort();
292 }
293 
294 const struct got_error *
295 got_error_from_errno(const char *prefix)
296 {
297 	struct got_custom_error *cerr = get_custom_err();
298 	struct got_error *err = &cerr->err;
299 	char strerr[128];
300 
301 	strerror_r(errno, strerr, sizeof(strerr));
302 	snprintf(cerr->msg, sizeof(cerr->msg), "%s: %s", prefix, strerr);
303 
304 	err->code = GOT_ERR_ERRNO;
305 	err->msg = cerr->msg;
306 	return err;
307 }
308 
309 const struct got_error *
310 got_error_from_errno2(const char *prefix, const char *prefix2)
311 {
312 	struct got_custom_error *cerr = get_custom_err();
313 	struct got_error *err = &cerr->err;
314 	char strerr[128];
315 
316 	strerror_r(errno, strerr, sizeof(strerr));
317 	snprintf(cerr->msg, sizeof(cerr->msg), "%s: %s: %s", prefix, prefix2,
318 	    strerr);
319 
320 	err->code = GOT_ERR_ERRNO;
321 	err->msg = cerr->msg;
322 	return err;
323 }
324 
325 const struct got_error *
326 got_error_from_errno3(const char *prefix, const char *prefix2,
327     const char *prefix3)
328 {
329 	struct got_custom_error *cerr = get_custom_err();
330 	struct got_error *err = &cerr->err;
331 	char strerr[128];
332 
333 	strerror_r(errno, strerr, sizeof(strerr));
334 	snprintf(cerr->msg, sizeof(cerr->msg), "%s: %s: %s: %s", prefix,
335 	    prefix2, prefix3, strerr);
336 
337 	err->code = GOT_ERR_ERRNO;
338 	err->msg = cerr->msg;
339 	return err;
340 }
341 
342 const struct got_error *
343 got_error_from_errno_fmt(const char *fmt, ...)
344 {
345 	struct got_custom_error *cerr = get_custom_err();
346 	struct got_error *err = &cerr->err;
347 	char buf[PATH_MAX * 4];
348 	char strerr[128];
349 	va_list ap;
350 
351 	va_start(ap, fmt);
352 	vsnprintf(buf, sizeof(buf), fmt, ap);
353 	va_end(ap);
354 
355 	strerror_r(errno, strerr, sizeof(strerr));
356 	snprintf(cerr->msg, sizeof(cerr->msg), "%s: %s", buf, strerr);
357 
358 	err->code = GOT_ERR_ERRNO;
359 	err->msg = cerr->msg;
360 	return err;
361 }
362 
363 const struct got_error *
364 got_error_set_errno(int code, const char *prefix)
365 {
366 	errno = code;
367 	return got_error_from_errno(prefix);
368 }
369 
370 const struct got_error *
371 got_ferror(FILE *f, int code)
372 {
373 	if (ferror(f))
374 		return got_error_from_errno("");
375 	return got_error(code);
376 }
377 
378 const struct got_error *
379 got_error_no_obj(struct got_object_id *id)
380 {
381 	char id_str[GOT_OBJECT_ID_HEX_MAXLEN];
382 	char msg[sizeof("object   not found") + sizeof(id_str)];
383 	int ret;
384 
385 	if (!got_object_id_hex(id, id_str, sizeof(id_str)))
386 		return got_error(GOT_ERR_NO_OBJ);
387 
388 	ret = snprintf(msg, sizeof(msg), "object %s not found", id_str);
389 	if (ret < 0 || (size_t)ret >= sizeof(msg))
390 		return got_error(GOT_ERR_NO_OBJ);
391 
392 	return got_error_msg(GOT_ERR_NO_OBJ, msg);
393 }
394 
395 const struct got_error *
396 got_error_checksum(struct got_object_id *id)
397 {
398 	char id_str[GOT_OBJECT_ID_HEX_MAXLEN];
399 	char msg[sizeof("checksum failure for object ") + sizeof(id_str)];
400 	int ret;
401 
402 	if (!got_object_id_hex(id, id_str, sizeof(id_str)))
403 		return got_error(GOT_ERR_OBJ_CSUM);
404 
405 	ret = snprintf(msg, sizeof(msg), "checksum failure for object %s",
406 	    id_str);
407 	if (ret < 0 || (size_t)ret >= sizeof(msg))
408 		return got_error(GOT_ERR_OBJ_CSUM);
409 
410 	return got_error_msg(GOT_ERR_OBJ_CSUM, msg);
411 }
412 
413 const struct got_error *
414 got_error_not_ref(const char *refname)
415 {
416 	char msg[sizeof("reference   not found") + 1004];
417 	int ret;
418 
419 	ret = snprintf(msg, sizeof(msg), "reference %s not found", refname);
420 	if (ret < 0 || (size_t)ret >= sizeof(msg))
421 		return got_error(GOT_ERR_NOT_REF);
422 
423 	return got_error_msg(GOT_ERR_NOT_REF, msg);
424 }
425 
426 const struct got_error *
427 got_error_uuid(uint32_t uuid_status, const char *prefix)
428 {
429 	switch (uuid_status) {
430 	case uuid_s_ok:
431 		return NULL;
432 	case uuid_s_bad_version:
433 		return got_error(GOT_ERR_UUID_VERSION);
434 	case uuid_s_invalid_string_uuid:
435 		return got_error(GOT_ERR_UUID_INVALID);
436 	case uuid_s_no_memory:
437 		return got_error_set_errno(ENOMEM, prefix);
438 	default:
439 		return got_error(GOT_ERR_UUID);
440 	}
441 }
442 
443 const struct got_error *
444 got_error_path(const char *path, int code)
445 {
446 	struct got_custom_error *cerr = get_custom_err();
447 	struct got_error *err = &cerr->err;
448 	size_t i;
449 
450 	for (i = 0; i < nitems(got_errors); i++) {
451 		if (code == got_errors[i].code) {
452 			err->code = code;
453 			snprintf(cerr->msg, sizeof(cerr->msg), "%s: %s", path,
454 			    got_errors[i].msg);
455 			err->msg = cerr->msg;
456 			return err;
457 		}
458 	}
459 
460 	abort();
461 }
462 
463 const struct got_error *
464 got_error_fmt(int code, const char *fmt, ...)
465 {
466 	struct got_custom_error *cerr = get_custom_err();
467 	struct got_error *err = &cerr->err;
468 	char buf[PATH_MAX * 4];
469 	va_list ap;
470 	size_t i;
471 
472 	va_start(ap, fmt);
473 	vsnprintf(buf, sizeof(buf), fmt, ap);
474 	va_end(ap);
475 
476 	for (i = 0; i < nitems(got_errors); i++) {
477 		if (code == got_errors[i].code) {
478 			err->code = code;
479 			snprintf(cerr->msg, sizeof(cerr->msg), "%s: %s", buf,
480 			    got_errors[i].msg);
481 			err->msg = cerr->msg;
482 			return err;
483 		}
484 	}
485 
486 	abort();
487 }
488 
489 int
490 got_err_open_nofollow_on_symlink(void)
491 {
492 	/*
493 	 * Check whether open(2) with O_NOFOLLOW failed on a symlink.
494 	 * Posix mandates ELOOP and OpenBSD follows it. Others return
495 	 * different error codes. We carry this workaround to help the
496 	 * portable version a little.
497 	 */
498 	return (errno == ELOOP
499 #ifdef EMLINK
500 	|| errno == EMLINK
501 #endif
502 #ifdef EFTYPE
503 	|| errno == EFTYPE
504 #endif
505 	);
506 }