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