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/uio.h>
40 
41 #include <ctype.h>
42 #include <limits.h>
43 #include <paths.h>
44 #include <stdint.h>
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <string.h>
48 #include <unistd.h>
49 
50 #include "got_error.h"
51 #include "got_object.h"
52 
53 #include "got_compat.h"
54 
55 #include "got_lib_delta.h"
56 #include "got_lib_object.h"
57 #include "got_lib_privsep.h"
58 
59 struct imsgbuf ibuf;
60 
61 static const struct got_error *
62 send_patch(const char *oldname, const char *newname, int git)
63 {
64 	struct got_imsg_patch p;
65 
66 	memset(&p, 0, sizeof(p));
67 
68 	if (oldname != NULL)
69 		strlcpy(p.old, oldname, sizeof(p.old));
70 
71 	if (newname != NULL)
72 		strlcpy(p.new, newname, sizeof(p.new));
73 
74 	p.git = git;
75 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH, 0, 0, -1,
76 	    &p, sizeof(p)) == -1)
77 		return got_error_from_errno("imsg_compose GOT_IMSG_PATCH");
78 	return NULL;
79 }
80 
81 static const struct got_error *
82 send_patch_done(void)
83 {
84 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH_DONE, 0, 0, -1,
85 	    NULL, 0) == -1)
86 		return got_error_from_errno("imsg_compose GOT_IMSG_PATCH_EOF");
87 	if (imsg_flush(&ibuf) == -1)
88 		return got_error_from_errno("imsg_flush");
89 	return NULL;
90 }
91 
92 /* based on fetchname from usr.bin/patch/util.c */
93 static const struct got_error *
94 filename(const char *at, char **name)
95 {
96 	char	*tmp, *t;
97 
98 	*name = NULL;
99 	if (*at == '\0')
100 		return NULL;
101 
102 	while (isspace((unsigned char)*at))
103 		at++;
104 
105 	/* files can be created or removed by diffing against /dev/null */
106 	if (!strncmp(at, _PATH_DEVNULL, sizeof(_PATH_DEVNULL) - 1))
107 		return NULL;
108 
109 	tmp = strdup(at);
110 	if (tmp == NULL)
111 		return got_error_from_errno("strdup");
112 	if ((t = strchr(tmp, '\t')) != NULL)
113 		*t = '\0';
114 	if ((t = strchr(tmp, '\n')) != NULL)
115 		*t = '\0';
116 
117 	*name = strdup(tmp);
118 	free(tmp);
119 	if (*name == NULL)
120 		return got_error_from_errno("strdup");
121 	return NULL;
122 }
123 
124 static const struct got_error *
125 find_patch(int *done, FILE *fp)
126 {
127 	const struct got_error *err = NULL;
128 	char	*old = NULL, *new = NULL;
129 	char	*line = NULL;
130 	size_t	 linesize = 0;
131 	ssize_t	 linelen;
132 	int	 create, rename = 0, git = 0;
133 
134 	while ((linelen = getline(&line, &linesize, fp)) != -1) {
135 		/*
136 		 * Ignore the Index name like GNU and larry' patch,
137 		 * we don't have to follow POSIX.
138 		 */
139 
140 		if (!strncmp(line, "--- ", 4)) {
141 			free(old);
142 			err = filename(line+4, &old);
143 		} else if (rename && !strncmp(line, "rename from ", 12)) {
144 			free(old);
145 			err = filename(line+12, &old);
146 		} else if (!strncmp(line, "+++ ", 4)) {
147 			free(new);
148 			err = filename(line+4, &new);
149 		} else if (rename && !strncmp(line, "rename to ", 10)) {
150 			free(new);
151 			err = filename(line + 10, &new);
152 		} else if (git && !strncmp(line, "similarity index 100%", 21))
153 			rename = 1;
154 		else if (!strncmp(line, "diff --git a/", 13))
155 			git = 1;
156 
157 		if (err)
158 			break;
159 
160 		/*
161 		 * Git-style diffs with "similarity index 100%" don't
162 		 * have any hunks and ends with the "rename to foobar"
163 		 * line.
164 		 */
165 		if (rename && old != NULL && new != NULL) {
166 			*done = 1;
167 			err = send_patch(old, new, git);
168 			break;
169 		}
170 
171 		if (!strncmp(line, "@@ -", 4)) {
172 			create = !strncmp(line+4, "0,0", 3);
173 			if ((old == NULL && new == NULL) ||
174 			    (!create && old == NULL))
175 				err = got_error(GOT_ERR_PATCH_MALFORMED);
176 			else
177 				err = send_patch(old, new, git);
178 
179 			if (err)
180 				break;
181 
182 			/* rewind to previous line */
183 			if (fseeko(fp, -linelen, SEEK_CUR) == -1)
184 				err = got_error_from_errno("fseeko");
185 			break;
186 		}
187 	}
188 
189 	free(old);
190 	free(new);
191 	free(line);
192 	if (ferror(fp) && err == NULL)
193 		err = got_error_from_errno("getline");
194 	if (feof(fp) && err == NULL)
195 		err = got_error(GOT_ERR_NO_PATCH);
196 	return err;
197 }
198 
199 static const struct got_error *
200 strtolnum(char **str, int *n)
201 {
202 	char		*p, c;
203 	const char	*errstr;
204 
205 	for (p = *str; isdigit((unsigned char)*p); ++p)
206 		/* nop */;
207 
208 	c = *p;
209 	*p = '\0';
210 
211 	*n = strtonum(*str, 0, INT_MAX, &errstr);
212 	if (errstr != NULL)
213 		return got_error(GOT_ERR_PATCH_MALFORMED);
214 
215 	*p = c;
216 	*str = p;
217 	return NULL;
218 }
219 
220 static const struct got_error *
221 parse_hdr(char *s, int *done, struct got_imsg_patch_hunk *hdr)
222 {
223 	static const struct got_error *err = NULL;
224 
225 	if (strncmp(s, "@@ -", 4)) {
226 		*done = 1;
227 		return NULL;
228 	}
229 
230 	s += 4;
231 	if (!*s)
232 		return NULL;
233 	err = strtolnum(&s, &hdr->oldfrom);
234 	if (err)
235 		return err;
236 	if (*s == ',') {
237 		s++;
238 		err = strtolnum(&s, &hdr->oldlines);
239 		if (err)
240 			return err;
241 	} else
242 		hdr->oldlines = 1;
243 
244 	if (*s == ' ')
245 		s++;
246 
247 	if (*s != '+' || !*++s)
248 		return got_error(GOT_ERR_PATCH_MALFORMED);
249 	err = strtolnum(&s, &hdr->newfrom);
250 	if (err)
251 		return err;
252 	if (*s == ',') {
253 		s++;
254 		err = strtolnum(&s, &hdr->newlines);
255 		if (err)
256 			return err;
257 	} else
258 		hdr->newlines = 1;
259 
260 	if (*s == ' ')
261 		s++;
262 
263 	if (*s != '@')
264 		return got_error(GOT_ERR_PATCH_MALFORMED);
265 
266 	if (hdr->oldfrom >= INT_MAX - hdr->oldlines ||
267 	    hdr->newfrom >= INT_MAX - hdr->newlines ||
268 	    /* not so sure about this one */
269 	    hdr->oldlines >= INT_MAX - hdr->newlines - 1 ||
270 	    (hdr->oldlines == 0 && hdr->newlines == 0))
271 		return got_error(GOT_ERR_PATCH_MALFORMED);
272 
273 	if (hdr->oldlines == 0) {
274 		/* larry says to "do append rather than insert"; I don't
275 		 * quite get it, but i trust him.
276 		 */
277 		hdr->oldfrom++;
278 	}
279 
280 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH_HUNK, 0, 0, -1,
281 	    hdr, sizeof(*hdr)) == -1)
282 		return got_error_from_errno(
283 		    "imsg_compose GOT_IMSG_PATCH_HUNK");
284 	return NULL;
285 }
286 
287 static const struct got_error *
288 send_line(const char *line)
289 {
290 	static const struct got_error *err = NULL;
291 	char *p = NULL;
292 
293 	if (*line != '+' && *line != '-' && *line != ' ' && *line != '\\') {
294 		if (asprintf(&p, " %s", line) == -1)
295 			return got_error_from_errno("asprintf");
296 		line = p;
297 	}
298 
299 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH_LINE, 0, 0, -1,
300 	    line, strlen(line) + 1) == -1)
301 		err = got_error_from_errno(
302 		    "imsg_compose GOT_IMSG_PATCH_LINE");
303 
304 	free(p);
305 	return err;
306 }
307 
308 static const struct got_error *
309 peek_special_line(FILE *fp)
310 {
311 	const struct got_error *err;
312 	int ch;
313 
314 	ch = fgetc(fp);
315 	if (ch != EOF && ch != '\\') {
316 		ungetc(ch, fp);
317 		return NULL;
318 	}
319 
320 	if (ch == '\\') {
321 		err = send_line("\\");
322 		if (err)
323 			return err;
324 	}
325 
326 	while (ch != EOF && ch != '\n')
327 		ch = fgetc(fp);
328 
329 	if (ch != EOF || feof(fp))
330 		return NULL;
331 	return got_error(GOT_ERR_IO);
332 }
333 
334 static const struct got_error *
335 parse_hunk(FILE *fp, int *done)
336 {
337 	static const struct got_error *err = NULL;
338 	struct got_imsg_patch_hunk hdr;
339 	char	*line = NULL, ch;
340 	size_t	 linesize = 0;
341 	ssize_t	 linelen;
342 	int	 leftold, leftnew;
343 
344 	linelen = getline(&line, &linesize, fp);
345 	if (linelen == -1) {
346 		*done = 1;
347 		goto done;
348 	}
349 
350 	err = parse_hdr(line, done, &hdr);
351 	if (err)
352 		goto done;
353 	if (*done) {
354 		if (fseeko(fp, -linelen, SEEK_CUR) == -1)
355 			err = got_error_from_errno("fseeko");
356 		goto done;
357 	}
358 
359 	leftold = hdr.oldlines;
360 	leftnew = hdr.newlines;
361 
362 	while (leftold > 0 || leftnew > 0) {
363 		linelen = getline(&line, &linesize, fp);
364 		if (linelen == -1) {
365 			if (ferror(fp)) {
366 				err = got_error_from_errno("getline");
367 				goto done;
368 			}
369 
370 			/* trailing newlines may be chopped */
371 			if (leftold < 3 && leftnew < 3) {
372 				*done = 1;
373 				break;
374 			}
375 
376 			err = got_error(GOT_ERR_PATCH_TRUNCATED);
377 			goto done;
378 		}
379 		if (line[linelen - 1] == '\n')
380 			line[linelen - 1] = '\0';
381 
382 		/* usr.bin/patch allows '=' as context char */
383 		if (*line == '=')
384 			*line = ' ';
385 
386 		ch = *line;
387 		if (ch == '\t' || ch == '\0')
388 			ch = ' ';	/* the space got eaten */
389 
390 		switch (ch) {
391 		case '-':
392 			leftold--;
393 			break;
394 		case ' ':
395 			leftold--;
396 			leftnew--;
397 			break;
398 		case '+':
399 			leftnew--;
400 			break;
401 		default:
402 			err = got_error(GOT_ERR_PATCH_MALFORMED);
403 			goto done;
404 		}
405 
406 		if (leftold < 0 || leftnew < 0) {
407 			err = got_error(GOT_ERR_PATCH_MALFORMED);
408 			goto done;
409 		}
410 
411 		err = send_line(line);
412 		if (err)
413 			goto done;
414 
415 		if ((ch == '-' && leftold == 0) ||
416 		    (ch == '+' && leftnew == 0)) {
417 			err = peek_special_line(fp);
418 			if (err)
419 				goto done;
420 		}
421 	}
422 
423 done:
424 	free(line);
425 	return err;
426 }
427 
428 static const struct got_error *
429 read_patch(struct imsgbuf *ibuf, int fd)
430 {
431 	const struct got_error *err = NULL;
432 	FILE *fp;
433 	int patch_found = 0;
434 
435 	if ((fp = fdopen(fd, "r")) == NULL) {
436 		err = got_error_from_errno("fdopen");
437 		close(fd);
438 		return err;
439 	}
440 
441 	while (!feof(fp)) {
442 		int done = 0;
443 
444 		err = find_patch(&done, fp);
445 		if (err)
446 			goto done;
447 
448 		patch_found = 1;
449 
450 		while (!done) {
451 			err = parse_hunk(fp, &done);
452 			if (err)
453 				goto done;
454 		}
455 
456 		err = send_patch_done();
457 		if (err)
458 			goto done;
459 	}
460 
461 done:
462 	fclose(fp);
463 
464 	/* ignore trailing gibberish */
465 	if (err != NULL && err->code == GOT_ERR_NO_PATCH && patch_found)
466 		err = NULL;
467 
468 	return err;
469 }
470 
471 int
472 main(int argc, char **argv)
473 {
474 	const struct got_error *err = NULL;
475 	struct imsg imsg;
476 #if 0
477 	static int attached;
478 	while (!attached)
479 		sleep(1);
480 #endif
481 
482 	imsg_init(&ibuf, GOT_IMSG_FD_CHILD);
483 #ifndef PROFILE
484 	/* revoke access to most system calls */
485 	if (pledge("stdio recvfd", NULL) == -1) {
486 		err = got_error_from_errno("pledge");
487 		got_privsep_send_error(&ibuf, err);
488 		return 1;
489 	}
490 
491 	/* revoke fs access */
492 	if (landlock_no_fs() == -1) {
493 		err = got_error_from_errno("landlock_no_fs");
494 		got_privsep_send_error(&ibuf, err);
495 		return 1;
496 	}
497 #endif
498 
499 	err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
500 	if (err)
501 		goto done;
502 	if (imsg.hdr.type != GOT_IMSG_PATCH_FILE || imsg.fd == -1) {
503 		err = got_error(GOT_ERR_PRIVSEP_MSG);
504 		goto done;
505 	}
506 
507 	err = read_patch(&ibuf, imsg.fd);
508 	if (err)
509 		goto done;
510 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH_EOF, 0, 0, -1,
511 	    NULL, 0) == -1) {
512 		err = got_error_from_errno("imsg_compose GOT_IMSG_PATCH_EOF");
513 		goto done;
514 	}
515 	err = got_privsep_flush_imsg(&ibuf);
516 done:
517 	imsg_free(&imsg);
518 	if (err != NULL) {
519 		got_privsep_send_error(&ibuf, err);
520 		err = NULL;
521 	}
522 	if (close(GOT_IMSG_FD_CHILD) == -1 && err == NULL)
523 		err = got_error_from_errno("close");
524 	if (err && err->code != GOT_ERR_PRIVSEP_PIPE)
525 		fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
526 	return err ? 1 : 0;
527 }