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Date:: Thu Jul 7 13:40:32 2022 UTC
Message:: use got_privsep_flush_imsg instead of reinventing it ok stsp@
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1 /*
2  * Copyright 1986, Larry Wall
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following condition is met:
6  * 1. Redistributions of source code must retain the above copyright notice,
7  * this condition and the following disclaimer.
8  *
9  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND ANY
10  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
11  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
12  * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
13  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
14  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
15  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
16  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
17  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
18  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
19  * SUCH DAMAGE.
20  */
21 
22 /*
23  * Copyright (c) 2022 Omar Polo <op@openbsd.org>
24  *
25  * Permission to use, copy, modify, and distribute this software for any
26  * purpose with or without fee is hereby granted, provided that the above
27  * copyright notice and this permission notice appear in all copies.
28  *
29  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
30  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
31  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
32  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
33  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
34  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
35  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
36  */
37 
38 #include <sys/types.h>
39 #include <sys/queue.h>
40 #include <sys/uio.h>
41 
42 #include <ctype.h>
43 #include <limits.h>
44 #include <paths.h>
45 #include <sha1.h>
46 #include <stdint.h>
47 #include <stdio.h>
48 #include <stdlib.h>
49 #include <string.h>
50 #include <unistd.h>
51 #include <imsg.h>
52 
53 #include "got_error.h"
54 #include "got_object.h"
55 
56 #include "got_lib_delta.h"
57 #include "got_lib_object.h"
58 #include "got_lib_privsep.h"
59 #include "got_lib_sha1.h"
60 
61 struct imsgbuf ibuf;
62 
63 static const struct got_error *
64 send_patch(const char *oldname, const char *newname, const char *commitid,
65     const char *blob, int git)
66 {
67 	struct got_imsg_patch p;
68 
69 	memset(&p, 0, sizeof(p));
70 
71 	if (oldname != NULL)
72 		strlcpy(p.old, oldname, sizeof(p.old));
73 
74 	if (newname != NULL)
75 		strlcpy(p.new, newname, sizeof(p.new));
76 
77 	if (commitid != NULL)
78 		strlcpy(p.cid, commitid, sizeof(p.cid));
79 
80 	if (blob != NULL)
81 		strlcpy(p.blob, blob, sizeof(p.blob));
82 
83 	p.git = git;
84 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH, 0, 0, -1, &p, sizeof(p)) == -1)
85 		return got_error_from_errno("imsg_compose GOT_IMSG_PATCH");
86 	return NULL;
87 }
88 
89 static const struct got_error *
90 send_patch_done(void)
91 {
92 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH_DONE, 0, 0, -1,
93 	    NULL, 0) == -1)
94 		return got_error_from_errno("imsg_compose GOT_IMSG_PATCH_EOF");
95 	return got_privsep_flush_imsg(&ibuf);
96 }
97 
98 /* based on fetchname from usr.bin/patch/util.c */
99 static const struct got_error *
100 filename(const char *at, char **name)
101 {
102 	char	*tmp, *t;
103 
104 	*name = NULL;
105 	if (*at == '\0')
106 		return NULL;
107 
108 	while (isspace((unsigned char)*at))
109 		at++;
110 
111 	/* files can be created or removed by diffing against /dev/null */
112 	if (!strncmp(at, _PATH_DEVNULL, sizeof(_PATH_DEVNULL) - 1))
113 		return NULL;
114 
115 	tmp = strdup(at);
116 	if (tmp == NULL)
117 		return got_error_from_errno("strdup");
118 	if ((t = strchr(tmp, '\t')) != NULL)
119 		*t = '\0';
120 	if ((t = strchr(tmp, '\n')) != NULL)
121 		*t = '\0';
122 
123 	*name = strdup(tmp);
124 	free(tmp);
125 	if (*name == NULL)
126 		return got_error_from_errno("strdup");
127 	return NULL;
128 }
129 
130 static const struct got_error *
131 blobid(const char *line, char **blob, int git)
132 {
133 	uint8_t digest[SHA1_DIGEST_LENGTH];
134 	size_t len;
135 
136 	*blob = NULL;
137 
138 	len = strspn(line, "0123456789abcdefABCDEF");
139 	if ((*blob = strndup(line, len)) == NULL)
140 		return got_error_from_errno("strndup");
141 
142 	if (!git && !got_parse_sha1_digest(digest, *blob)) {
143 		/* silently ignore invalid blob ids */
144 		free(*blob);
145 		*blob = NULL;
146 	}
147 	return NULL;
148 }
149 
150 static const struct got_error *
151 patch_start(int *git, char **cid, FILE *fp)
152 {
153 	const struct got_error *err = NULL;
154 	char	*line = NULL;
155 	size_t	 linesize = 0;
156 	ssize_t	 linelen;
157 
158 	*git = 0;
159 
160 	while ((linelen = getline(&line, &linesize, fp)) != -1) {
161 		if (!strncmp(line, "diff --git ", 11)) {
162 			*git = 1;
163 			free(*cid);
164 			*cid = NULL;
165 			break;
166 		} else if (!strncmp(line, "diff ", 5)) {
167 			*git = 0;
168 			free(*cid);
169 			*cid = NULL;
170 		} else if (!strncmp(line, "commit - ", 9)) {
171 			free(*cid);
172 			err = blobid(line + 9, cid, *git);
173 			if (err)
174 				break;
175 		} else if (!strncmp(line, "--- ", 4) ||
176 		    !strncmp(line, "+++ ", 4) ||
177 		    !strncmp(line, "blob - ", 7)) {
178 			/* rewind to previous line */
179 			if (fseeko(fp, -linelen, SEEK_CUR) == -1)
180 				err = got_error_from_errno("fseeko");
181 			break;
182 		}
183 	}
184 
185 	free(line);
186 	if (ferror(fp) && err == NULL)
187 		err = got_error_from_errno("getline");
188 	if (feof(fp) && err == NULL)
189 		err = got_error(GOT_ERR_NO_PATCH);
190 	return err;
191 }
192 
193 static const struct got_error *
194 find_diff(int *done, int *next, FILE *fp, int git, const char *commitid)
195 {
196 	const struct got_error *err = NULL;
197 	char	*old = NULL, *new = NULL;
198 	char	*blob = NULL;
199 	char	*line = NULL;
200 	size_t	 linesize = 0;
201 	ssize_t	 linelen;
202 	int	 create, rename = 0;
203 
204 	*done = 0;
205 	*next = 0;
206 	while ((linelen = getline(&line, &linesize, fp)) != -1) {
207 		/*
208 		 * Ignore the Index name like GNU and larry' patch,
209 		 * we don't have to follow POSIX.
210 		 */
211 
212 		if (!strncmp(line, "--- ", 4)) {
213 			free(old);
214 			err = filename(line+4, &old);
215 		} else if (rename && !strncmp(line, "rename from ", 12)) {
216 			free(old);
217 			err = filename(line+12, &old);
218 		} else if (!strncmp(line, "+++ ", 4)) {
219 			free(new);
220 			err = filename(line+4, &new);
221 		} else if (!git && !strncmp(line, "blob - ", 7)) {
222 			free(blob);
223 			err = blobid(line + 7, &blob, git);
224 		} else if (rename && !strncmp(line, "rename to ", 10)) {
225 			free(new);
226 			err = filename(line + 10, &new);
227 		} else if (git && !strncmp(line, "similarity index 100%", 21))
228 			rename = 1;
229 		else if (git && !strncmp(line, "index ", 6)) {
230 			free(blob);
231 			err = blobid(line + 6, &blob, git);
232 		} else if (!strncmp(line, "diff ", 5)) {
233 			/* rewind to previous line */
234 			if (fseeko(fp, -linelen, SEEK_CUR) == -1)
235 				err = got_error_from_errno("fseeko");
236 			*next = 1;
237 			break;
238 		}
239 
240 		if (err)
241 			break;
242 
243 		/*
244 		 * Git-style diffs with "similarity index 100%" don't
245 		 * have any hunks and ends with the "rename to foobar"
246 		 * line.
247 		 */
248 		if (rename && old != NULL && new != NULL) {
249 			*done = 1;
250 			err = send_patch(old, new, commitid,
251 			    blob, git);
252 			break;
253 		}
254 
255 		if (!strncmp(line, "@@ -", 4)) {
256 			create = !strncmp(line+4, "0,0", 3);
257 			if ((old == NULL && new == NULL) ||
258 			    (!create && old == NULL))
259 				err = got_error(GOT_ERR_PATCH_MALFORMED);
260 			else
261 				err = send_patch(old, new, commitid,
262 				    blob, git);
263 
264 			if (err)
265 				break;
266 
267 			/* rewind to previous line */
268 			if (fseeko(fp, -linelen, SEEK_CUR) == -1)
269 				err = got_error_from_errno("fseeko");
270 			break;
271 		}
272 	}
273 
274 	free(old);
275 	free(new);
276 	free(blob);
277 	free(line);
278 	if (ferror(fp) && err == NULL)
279 		err = got_error_from_errno("getline");
280 	if (feof(fp) && err == NULL)
281 		err = got_error(GOT_ERR_NO_PATCH);
282 	return err;
283 }
284 
285 static const struct got_error *
286 strtolnum(char **str, int *n)
287 {
288 	char		*p, c;
289 	const char	*errstr;
290 
291 	for (p = *str; isdigit((unsigned char)*p); ++p)
292 		/* nop */;
293 
294 	c = *p;
295 	*p = '\0';
296 
297 	*n = strtonum(*str, 0, INT_MAX, &errstr);
298 	if (errstr != NULL)
299 		return got_error(GOT_ERR_PATCH_MALFORMED);
300 
301 	*p = c;
302 	*str = p;
303 	return NULL;
304 }
305 
306 static const struct got_error *
307 parse_hdr(char *s, int *done, struct got_imsg_patch_hunk *hdr)
308 {
309 	static const struct got_error *err = NULL;
310 
311 	if (strncmp(s, "@@ -", 4)) {
312 		*done = 1;
313 		return NULL;
314 	}
315 
316 	s += 4;
317 	if (!*s)
318 		return NULL;
319 	err = strtolnum(&s, &hdr->oldfrom);
320 	if (err)
321 		return err;
322 	if (*s == ',') {
323 		s++;
324 		err = strtolnum(&s, &hdr->oldlines);
325 		if (err)
326 			return err;
327 	} else
328 		hdr->oldlines = 1;
329 
330 	if (*s == ' ')
331 		s++;
332 
333 	if (*s != '+' || !*++s)
334 		return got_error(GOT_ERR_PATCH_MALFORMED);
335 	err = strtolnum(&s, &hdr->newfrom);
336 	if (err)
337 		return err;
338 	if (*s == ',') {
339 		s++;
340 		err = strtolnum(&s, &hdr->newlines);
341 		if (err)
342 			return err;
343 	} else
344 		hdr->newlines = 1;
345 
346 	if (*s == ' ')
347 		s++;
348 
349 	if (*s != '@')
350 		return got_error(GOT_ERR_PATCH_MALFORMED);
351 
352 	if (hdr->oldfrom >= INT_MAX - hdr->oldlines ||
353 	    hdr->newfrom >= INT_MAX - hdr->newlines ||
354 	    /* not so sure about this one */
355 	    hdr->oldlines >= INT_MAX - hdr->newlines - 1 ||
356 	    (hdr->oldlines == 0 && hdr->newlines == 0))
357 		return got_error(GOT_ERR_PATCH_MALFORMED);
358 
359 	if (hdr->oldlines == 0) {
360 		/* larry says to "do append rather than insert"; I don't
361 		 * quite get it, but i trust him.
362 		 */
363 		hdr->oldfrom++;
364 	}
365 
366 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH_HUNK, 0, 0, -1,
367 	    hdr, sizeof(*hdr)) == -1)
368 		return got_error_from_errno(
369 		    "imsg_compose GOT_IMSG_PATCH_HUNK");
370 	return NULL;
371 }
372 
373 static const struct got_error *
374 send_line(const char *line)
375 {
376 	static const struct got_error *err = NULL;
377 	char *p = NULL;
378 
379 	if (*line != '+' && *line != '-' && *line != ' ' && *line != '\\') {
380 		if (asprintf(&p, " %s", line) == -1)
381 			return got_error_from_errno("asprintf");
382 		line = p;
383 	}
384 
385 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH_LINE, 0, 0, -1,
386 	    line, strlen(line) + 1) == -1)
387 		err = got_error_from_errno(
388 		    "imsg_compose GOT_IMSG_PATCH_LINE");
389 
390 	free(p);
391 	return err;
392 }
393 
394 static const struct got_error *
395 peek_special_line(FILE *fp)
396 {
397 	const struct got_error *err;
398 	int ch;
399 
400 	ch = fgetc(fp);
401 	if (ch != EOF && ch != '\\') {
402 		ungetc(ch, fp);
403 		return NULL;
404 	}
405 
406 	if (ch == '\\') {
407 		err = send_line("\\");
408 		if (err)
409 			return err;
410 	}
411 
412 	while (ch != EOF && ch != '\n')
413 		ch = fgetc(fp);
414 
415 	if (ch != EOF || feof(fp))
416 		return NULL;
417 	return got_error(GOT_ERR_IO);
418 }
419 
420 static const struct got_error *
421 parse_hunk(FILE *fp, int *done)
422 {
423 	static const struct got_error *err = NULL;
424 	struct got_imsg_patch_hunk hdr;
425 	char	*line = NULL, ch;
426 	size_t	 linesize = 0;
427 	ssize_t	 linelen;
428 	int	 leftold, leftnew;
429 
430 	linelen = getline(&line, &linesize, fp);
431 	if (linelen == -1) {
432 		*done = 1;
433 		goto done;
434 	}
435 
436 	err = parse_hdr(line, done, &hdr);
437 	if (err)
438 		goto done;
439 	if (*done) {
440 		if (fseeko(fp, -linelen, SEEK_CUR) == -1)
441 			err = got_error_from_errno("fseeko");
442 		goto done;
443 	}
444 
445 	leftold = hdr.oldlines;
446 	leftnew = hdr.newlines;
447 
448 	while (leftold > 0 || leftnew > 0) {
449 		linelen = getline(&line, &linesize, fp);
450 		if (linelen == -1) {
451 			if (ferror(fp)) {
452 				err = got_error_from_errno("getline");
453 				goto done;
454 			}
455 
456 			/* trailing newlines may be chopped */
457 			if (leftold < 3 && leftnew < 3) {
458 				*done = 1;
459 				break;
460 			}
461 
462 			err = got_error(GOT_ERR_PATCH_TRUNCATED);
463 			goto done;
464 		}
465 		if (line[linelen - 1] == '\n')
466 			line[linelen - 1] = '\0';
467 
468 		/* usr.bin/patch allows '=' as context char */
469 		if (*line == '=')
470 			*line = ' ';
471 
472 		ch = *line;
473 		if (ch == '\t' || ch == '\0')
474 			ch = ' ';	/* the space got eaten */
475 
476 		switch (ch) {
477 		case '-':
478 			leftold--;
479 			break;
480 		case ' ':
481 			leftold--;
482 			leftnew--;
483 			break;
484 		case '+':
485 			leftnew--;
486 			break;
487 		default:
488 			err = got_error(GOT_ERR_PATCH_MALFORMED);
489 			goto done;
490 		}
491 
492 		if (leftold < 0 || leftnew < 0) {
493 			err = got_error(GOT_ERR_PATCH_MALFORMED);
494 			goto done;
495 		}
496 
497 		err = send_line(line);
498 		if (err)
499 			goto done;
500 
501 		if ((ch == '-' && leftold == 0) ||
502 		    (ch == '+' && leftnew == 0)) {
503 			err = peek_special_line(fp);
504 			if (err)
505 				goto done;
506 		}
507 	}
508 
509 done:
510 	free(line);
511 	return err;
512 }
513 
514 static const struct got_error *
515 read_patch(struct imsgbuf *ibuf, int fd)
516 {
517 	const struct got_error *err = NULL;
518 	FILE *fp;
519 	int git, patch_found = 0;
520 	char *cid = NULL;
521 
522 	if ((fp = fdopen(fd, "r")) == NULL) {
523 		err = got_error_from_errno("fdopen");
524 		close(fd);
525 		return err;
526 	}
527 
528 	while ((err = patch_start(&git, &cid, fp)) == NULL) {
529 		int done, next;
530 
531 		err = find_diff(&done, &next, fp, git, cid);
532 		if (err)
533 			goto done;
534 		if (next)
535 			continue;
536 
537 		patch_found = 1;
538 
539 		while (!done) {
540 			err = parse_hunk(fp, &done);
541 			if (err)
542 				goto done;
543 		}
544 
545 		err = send_patch_done();
546 		if (err)
547 			goto done;
548 	}
549 
550 done:
551 	fclose(fp);
552 	free(cid);
553 
554 	/* ignore trailing gibberish */
555 	if (err != NULL && err->code == GOT_ERR_NO_PATCH && patch_found)
556 		err = NULL;
557 
558 	return err;
559 }
560 
561 int
562 main(int argc, char **argv)
563 {
564 	const struct got_error *err = NULL;
565 	struct imsg imsg;
566 #if 0
567 	static int attached;
568 	while (!attached)
569 		sleep(1);
570 #endif
571 
572 	imsg_init(&ibuf, GOT_IMSG_FD_CHILD);
573 #ifndef PROFILE
574 	/* revoke access to most system calls */
575 	if (pledge("stdio recvfd", NULL) == -1) {
576 		err = got_error_from_errno("pledge");
577 		got_privsep_send_error(&ibuf, err);
578 		return 1;
579 	}
580 #endif
581 
582 	err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
583 	if (err)
584 		goto done;
585 	if (imsg.hdr.type != GOT_IMSG_PATCH_FILE || imsg.fd == -1) {
586 		err = got_error(GOT_ERR_PRIVSEP_MSG);
587 		goto done;
588 	}
589 
590 	err = read_patch(&ibuf, imsg.fd);
591 	if (err)
592 		goto done;
593 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH_EOF, 0, 0, -1,
594 	    NULL, 0) == -1) {
595 		err = got_error_from_errno("imsg_compose GOT_IMSG_PATCH_EOF");
596 		goto done;
597 	}
598 	err = got_privsep_flush_imsg(&ibuf);
599 done:
600 	imsg_free(&imsg);
601 	if (err != NULL) {
602 		got_privsep_send_error(&ibuf, err);
603 		err = NULL;
604 	}
605 	if (close(GOT_IMSG_FD_CHILD) == -1 && err == NULL)
606 		err = got_error_from_errno("close");
607 	if (err && err->code != GOT_ERR_PRIVSEP_PIPE)
608 		fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
609 	return err ? 1 : 0;
610 }