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 	/*
70 	 * Prefer the new name if it's not /dev/null and it's not
71 	 * a git-style diff.
72 	 */
73 	if (!git && newname != NULL && oldname != NULL)
74 		strlcpy(p.old, newname, sizeof(p.old));
75 	else if (oldname != NULL)
76 		strlcpy(p.old, oldname, sizeof(p.old));
77 
78 	if (newname != NULL)
79 		strlcpy(p.new, newname, sizeof(p.new));
80 
81 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH, 0, 0, -1,
82 	    &p, sizeof(p)) == -1)
83 		return got_error_from_errno("imsg_compose GOT_IMSG_PATCH");
84 	return NULL;
85 }
86 
87 static const struct got_error *
88 send_patch_done(void)
89 {
90 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH_DONE, 0, 0, -1,
91 	    NULL, 0) == -1)
92 		return got_error_from_errno("imsg_compose GOT_IMSG_PATCH_EOF");
93 	if (imsg_flush(&ibuf) == -1)
94 		return got_error_from_errno("imsg_flush");
95 	return NULL;
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, int strip)
101 {
102 	char	*fullname, *t;
103 	int	 l, tab;
104 
105 	*name = NULL;
106 	if (*at == '\0')
107 		return NULL;
108 
109 	while (isspace((unsigned char)*at))
110 		at++;
111 
112 	/* files can be created or removed by diffing against /dev/null */
113 	if (!strncmp(at, _PATH_DEVNULL, sizeof(_PATH_DEVNULL) - 1))
114 		return NULL;
115 
116 	t = strdup(at);
117 	if (t == NULL)
118 		return got_error_from_errno("strdup");
119 	*name = fullname = t;
120 	tab = strchr(t, '\t') != NULL;
121 
122 	/* strip off path components and NUL-terminate */
123 	for (l = strip;
124 	    *t != '\0' && ((tab && *t != '\t') || !isspace((unsigned char)*t));
125 	    ++t) {
126 		if (t[0] == '/' && t[1] != '/' && t[1] != '\0')
127 			if (--l >= 0)
128 				*name = t + 1;
129 	}
130 	*t = '\0';
131 
132 	*name = strdup(*name);
133 	free(fullname);
134 	if (*name == NULL)
135 		return got_error_from_errno("strdup");
136 	return NULL;
137 }
138 
139 static const struct got_error *
140 find_patch(FILE *fp)
141 {
142 	const struct got_error *err = NULL;
143 	char	*old = NULL, *new = NULL;
144 	char	*line = NULL;
145 	size_t	 linesize = 0;
146 	ssize_t	 linelen;
147 	int	 create, git = 0;
148 
149 	while ((linelen = getline(&line, &linesize, fp)) != -1) {
150 		/*
151 		 * Ignore the Index name like GNU and larry' patch,
152 		 * we don't have to follow POSIX.
153 		 */
154 
155 		if (git && !strncmp(line, "--- a/", 6)) {
156 			free(old);
157 			err = filename(line+6, &old, 0);
158 		} else if (!strncmp(line, "--- ", 4)) {
159 			free(old);
160 			err = filename(line+4, &old, 0);
161 		} else if (git && !strncmp(line, "+++ b/", 6)) {
162 			free(new);
163 			err = filename(line+6, &new, 0);
164 		} else if (!strncmp(line, "+++ ", 4)) {
165 			free(new);
166 			err = filename(line+4, &new, 0);
167 		} else if (!strncmp(line, "diff --git a/", 13))
168 			git = 1;
169 
170 		if (err)
171 			break;
172 
173 		if (!strncmp(line, "@@ -", 4)) {
174 			create = !strncmp(line+4, "0,0", 3);
175 			if ((old == NULL && new == NULL) ||
176 			    (!create && old == NULL))
177 				err = got_error(GOT_ERR_PATCH_MALFORMED);
178 			else
179 				err = send_patch(old, new, git);
180 
181 			if (err)
182 				break;
183 
184 			/* rewind to previous line */
185 			if (fseek(fp, linelen * -1, SEEK_CUR) == -1)
186 				err = got_error_from_errno("fseek");
187 			break;
188 		}
189 	}
190 
191 	free(old);
192 	free(new);
193 	free(line);
194 	if (ferror(fp) && err == NULL)
195 		err = got_error_from_errno("getline");
196 	if (feof(fp) && err == NULL)
197 		err = got_error(GOT_ERR_NO_PATCH);
198 	return err;
199 }
200 
201 static const struct got_error *
202 strtolnum(char **str, long *n)
203 {
204 	char		*p, c;
205 	const char	*errstr;
206 
207 	for (p = *str; isdigit((unsigned char)*p); ++p)
208 		/* nop */;
209 
210 	c = *p;
211 	*p = '\0';
212 
213 	*n = strtonum(*str, 0, LONG_MAX, &errstr);
214 	if (errstr != NULL)
215 		return got_error(GOT_ERR_PATCH_MALFORMED);
216 
217 	*p = c;
218 	*str = p;
219 	return NULL;
220 }
221 
222 static const struct got_error *
223 parse_hdr(char *s, int *ok, struct got_imsg_patch_hunk *hdr)
224 {
225 	static const struct got_error *err = NULL;
226 
227 	*ok = 1;
228 	if (strncmp(s, "@@ -", 4)) {
229 		*ok = 0;
230 		return NULL;
231 	}
232 
233 	s += 4;
234 	if (!*s)
235 		return NULL;
236 	err = strtolnum(&s, &hdr->oldfrom);
237 	if (err)
238 		return err;
239 	if (*s == ',') {
240 		s++;
241 		err = strtolnum(&s, &hdr->oldlines);
242 		if (err)
243 			return err;
244 	} else
245 		hdr->oldlines = 1;
246 
247 	if (*s == ' ')
248 		s++;
249 
250 	if (*s != '+' || !*++s)
251 		return got_error(GOT_ERR_PATCH_MALFORMED);
252 	err = strtolnum(&s, &hdr->newfrom);
253 	if (err)
254 		return err;
255 	if (*s == ',') {
256 		s++;
257 		err = strtolnum(&s, &hdr->newlines);
258 		if (err)
259 			return err;
260 	} else
261 		hdr->newlines = 1;
262 
263 	if (*s == ' ')
264 		s++;
265 
266 	if (*s != '@')
267 		return got_error(GOT_ERR_PATCH_MALFORMED);
268 
269 	if (hdr->oldfrom >= LONG_MAX - hdr->oldlines ||
270 	    hdr->newfrom >= LONG_MAX - hdr->newlines ||
271 	    /* not so sure about this one */
272 	    hdr->oldlines >= LONG_MAX - hdr->newlines - 1)
273 		return got_error(GOT_ERR_PATCH_MALFORMED);
274 
275 	if (hdr->oldlines == 0) {
276 		/* larry says to "do append rather than insert"; I don't
277 		 * quite get it, but i trust him.
278 		 */
279 		hdr->oldfrom++;
280 	}
281 
282 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH_HUNK, 0, 0, -1,
283 	    hdr, sizeof(*hdr)) == -1)
284 		return got_error_from_errno(
285 		    "imsg_compose GOT_IMSG_PATCH_HUNK");
286 	return NULL;
287 }
288 
289 static const struct got_error *
290 send_line(const char *line)
291 {
292 	static const struct got_error *err = NULL;
293 	char *p = NULL;
294 
295 	if (*line != '+' && *line != '-' && *line != ' ') {
296 		if (asprintf(&p, " %s", line) == -1)
297 			return got_error_from_errno("asprintf");
298 		line = p;
299 	}
300 
301 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH_LINE, 0, 0, -1,
302 	    line, strlen(line) + 1) == -1)
303 		err = got_error_from_errno(
304 		    "imsg_compose GOT_IMSG_PATCH_LINE");
305 
306 	free(p);
307 	return err;
308 }
309 
310 static const struct got_error *
311 parse_hunk(FILE *fp, int *ok)
312 {
313 	static const struct got_error *err = NULL;
314 	struct got_imsg_patch_hunk hdr;
315 	char	*line = NULL, ch;
316 	size_t	 linesize = 0;
317 	ssize_t	 linelen;
318 	long	 leftold, leftnew;
319 
320 	linelen = getline(&line, &linesize, fp);
321 	if (linelen == -1) {
322 		*ok = 0;
323 		goto done;
324 	}
325 
326 	err = parse_hdr(line, ok, &hdr);
327 	if (err)
328 		goto done;
329 	if (!*ok) {
330 		if (fseek(fp, linelen * -1, SEEK_CUR) == -1)
331 			err = got_error_from_errno("fseek");
332 		goto done;
333 	}
334 
335 	leftold = hdr.oldlines;
336 	leftnew = hdr.newlines;
337 
338 	while (leftold > 0 || leftnew > 0) {
339 		linelen = getline(&line, &linesize, fp);
340 		if (linelen == -1) {
341 			if (ferror(fp)) {
342 				err = got_error_from_errno("getline");
343 				goto done;
344 			}
345 
346 			/* trailing newlines may be chopped */
347 			if (leftold < 3 && leftnew < 3) {
348 				*ok = 0;
349 				break;
350 			}
351 
352 			err = got_error(GOT_ERR_PATCH_TRUNCATED);
353 			goto done;
354 		}
355 
356 		/* usr.bin/patch allows '=' as context char */
357 		if (*line == '=')
358 			*line = ' ';
359 
360 		ch = *line;
361 		if (ch == '\t' || ch == '\n')
362 			ch = ' ';	/* the space got eaten */
363 
364 		switch (ch) {
365 		case '-':
366 			leftold--;
367 			break;
368 		case ' ':
369 			leftold--;
370 			leftnew--;
371 			break;
372 		case '+':
373 			leftnew--;
374 			break;
375 		default:
376 			err = got_error(GOT_ERR_PATCH_MALFORMED);
377 			goto done;
378 		}
379 
380 		if (leftold < 0 || leftnew < 0) {
381 			err = got_error(GOT_ERR_PATCH_MALFORMED);
382 			goto done;
383 		}
384 
385 		err = send_line(line);
386 		if (err)
387 			goto done;
388 	}
389 
390 done:
391 	free(line);
392 	return err;
393 }
394 
395 static const struct got_error *
396 read_patch(struct imsgbuf *ibuf, int fd)
397 {
398 	const struct got_error *err = NULL;
399 	FILE *fp;
400 	int ok, patch_found = 0;
401 
402 	if ((fp = fdopen(fd, "r")) == NULL) {
403 		err = got_error_from_errno("fdopen");
404 		close(fd);
405 		return err;
406 	}
407 
408 	while (!feof(fp)) {
409 		err = find_patch(fp);
410 		if (err)
411 			goto done;
412 
413 		patch_found = 1;
414 		for (;;) {
415 			err = parse_hunk(fp, &ok);
416 			if (err)
417 				goto done;
418 			if (!ok) {
419 				err = send_patch_done();
420 				if (err)
421 					goto done;
422 				break;
423 			}
424 		}
425 	}
426 
427 done:
428 	fclose(fp);
429 
430 	/* ignore trailing gibberish */
431 	if (err != NULL && err->code == GOT_ERR_NO_PATCH && patch_found)
432 		err = NULL;
433 
434 	return err;
435 }
436 
437 int
438 main(int argc, char **argv)
439 {
440 	const struct got_error *err = NULL;
441 	struct imsg imsg;
442 #if 0
443 	static int attached;
444 	while (!attached)
445 		sleep(1);
446 #endif
447 
448 	imsg_init(&ibuf, GOT_IMSG_FD_CHILD);
449 #ifndef PROFILE
450 	/* revoke access to most system calls */
451 	if (pledge("stdio recvfd", NULL) == -1) {
452 		err = got_error_from_errno("pledge");
453 		got_privsep_send_error(&ibuf, err);
454 		return 1;
455 	}
456 #endif
457 
458 	err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
459 	if (err)
460 		goto done;
461 	if (imsg.hdr.type != GOT_IMSG_PATCH_FILE || imsg.fd == -1) {
462 		err = got_error(GOT_ERR_PRIVSEP_MSG);
463 		goto done;
464 	}
465 
466 	err = read_patch(&ibuf, imsg.fd);
467 	if (err)
468 		goto done;
469 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH_EOF, 0, 0, -1,
470 	    NULL, 0) == -1) {
471 		err = got_error_from_errno("imsg_compose GOT_IMSG_PATCH_EOF");
472 		goto done;
473 	}
474 	err = got_privsep_flush_imsg(&ibuf);
475 done:
476 	imsg_free(&imsg);
477 	if (err != NULL) {
478 		got_privsep_send_error(&ibuf, err);
479 		err = NULL;
480 	}
481 	if (close(GOT_IMSG_FD_CHILD) == -1 && err == NULL)
482 		err = got_error_from_errno("close");
483 	if (err && err->code != GOT_ERR_PRIVSEP_PIPE)
484 		fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
485 	return err ? 1 : 0;
486 }