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