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Date:: Sat May 14 18:55:37 2022 UTC
Message:: got patch: switch from fseek() to fseeko(), use unary minus while here ok op
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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 
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(int *done, 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, rename = 0, 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 (rename && !strncmp(line, "rename from ", 12)) {
145 			free(old);
146 			err = filename(line+12, &old);
147 		} else if (!strncmp(line, "+++ ", 4)) {
148 			free(new);
149 			err = filename(line+4, &new);
150 		} else if (rename && !strncmp(line, "rename to ", 10)) {
151 			free(new);
152 			err = filename(line + 10, &new);
153 		} else if (git && !strncmp(line, "similarity index 100%", 21))
154 			rename = 1;
155 		else if (!strncmp(line, "diff --git a/", 13))
156 			git = 1;
157 
158 		if (err)
159 			break;
160 
161 		/*
162 		 * Git-style diffs with "similarity index 100%" don't
163 		 * have any hunks and ends with the "rename to foobar"
164 		 * line.
165 		 */
166 		if (rename && old != NULL && new != NULL) {
167 			*done = 1;
168 			err = send_patch(old, new, git);
169 			break;
170 		}
171 
172 		if (!strncmp(line, "@@ -", 4)) {
173 			create = !strncmp(line+4, "0,0", 3);
174 			if ((old == NULL && new == NULL) ||
175 			    (!create && old == NULL))
176 				err = got_error(GOT_ERR_PATCH_MALFORMED);
177 			else
178 				err = send_patch(old, new, git);
179 
180 			if (err)
181 				break;
182 
183 			/* rewind to previous line */
184 			if (fseeko(fp, -linelen, SEEK_CUR) == -1)
185 				err = got_error_from_errno("fseeko");
186 			break;
187 		}
188 	}
189 
190 	free(old);
191 	free(new);
192 	free(line);
193 	if (ferror(fp) && err == NULL)
194 		err = got_error_from_errno("getline");
195 	if (feof(fp) && err == NULL)
196 		err = got_error(GOT_ERR_NO_PATCH);
197 	return err;
198 }
199 
200 static const struct got_error *
201 strtolnum(char **str, long *n)
202 {
203 	char		*p, c;
204 	const char	*errstr;
205 
206 	for (p = *str; isdigit((unsigned char)*p); ++p)
207 		/* nop */;
208 
209 	c = *p;
210 	*p = '\0';
211 
212 	*n = strtonum(*str, 0, LONG_MAX, &errstr);
213 	if (errstr != NULL)
214 		return got_error(GOT_ERR_PATCH_MALFORMED);
215 
216 	*p = c;
217 	*str = p;
218 	return NULL;
219 }
220 
221 static const struct got_error *
222 parse_hdr(char *s, int *done, struct got_imsg_patch_hunk *hdr)
223 {
224 	static const struct got_error *err = NULL;
225 
226 	if (strncmp(s, "@@ -", 4)) {
227 		*done = 1;
228 		return NULL;
229 	}
230 
231 	s += 4;
232 	if (!*s)
233 		return NULL;
234 	err = strtolnum(&s, &hdr->oldfrom);
235 	if (err)
236 		return err;
237 	if (*s == ',') {
238 		s++;
239 		err = strtolnum(&s, &hdr->oldlines);
240 		if (err)
241 			return err;
242 	} else
243 		hdr->oldlines = 1;
244 
245 	if (*s == ' ')
246 		s++;
247 
248 	if (*s != '+' || !*++s)
249 		return got_error(GOT_ERR_PATCH_MALFORMED);
250 	err = strtolnum(&s, &hdr->newfrom);
251 	if (err)
252 		return err;
253 	if (*s == ',') {
254 		s++;
255 		err = strtolnum(&s, &hdr->newlines);
256 		if (err)
257 			return err;
258 	} else
259 		hdr->newlines = 1;
260 
261 	if (*s == ' ')
262 		s++;
263 
264 	if (*s != '@')
265 		return got_error(GOT_ERR_PATCH_MALFORMED);
266 
267 	if (hdr->oldfrom >= LONG_MAX - hdr->oldlines ||
268 	    hdr->newfrom >= LONG_MAX - hdr->newlines ||
269 	    /* not so sure about this one */
270 	    hdr->oldlines >= LONG_MAX - hdr->newlines - 1 ||
271 	    (hdr->oldlines == 0 && hdr->newlines == 0))
272 		return got_error(GOT_ERR_PATCH_MALFORMED);
273 
274 	if (hdr->oldlines == 0) {
275 		/* larry says to "do append rather than insert"; I don't
276 		 * quite get it, but i trust him.
277 		 */
278 		hdr->oldfrom++;
279 	}
280 
281 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH_HUNK, 0, 0, -1,
282 	    hdr, sizeof(*hdr)) == -1)
283 		return got_error_from_errno(
284 		    "imsg_compose GOT_IMSG_PATCH_HUNK");
285 	return NULL;
286 }
287 
288 static const struct got_error *
289 send_line(const char *line)
290 {
291 	static const struct got_error *err = NULL;
292 	char *p = NULL;
293 
294 	if (*line != '+' && *line != '-' && *line != ' ' && *line != '\\') {
295 		if (asprintf(&p, " %s", line) == -1)
296 			return got_error_from_errno("asprintf");
297 		line = p;
298 	}
299 
300 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH_LINE, 0, 0, -1,
301 	    line, strlen(line) + 1) == -1)
302 		err = got_error_from_errno(
303 		    "imsg_compose GOT_IMSG_PATCH_LINE");
304 
305 	free(p);
306 	return err;
307 }
308 
309 static const struct got_error *
310 peek_special_line(FILE *fp)
311 {
312 	const struct got_error *err;
313 	int ch;
314 
315 	ch = fgetc(fp);
316 	if (ch != EOF && ch != '\\') {
317 		ungetc(ch, fp);
318 		return NULL;
319 	}
320 
321 	if (ch == '\\') {
322 		err = send_line("\\");
323 		if (err)
324 			return err;
325 	}
326 
327 	while (ch != EOF && ch != '\n')
328 		ch = fgetc(fp);
329 
330 	if (ch != EOF || feof(fp))
331 		return NULL;
332 	return got_error(GOT_ERR_IO);
333 }
334 
335 static const struct got_error *
336 parse_hunk(FILE *fp, int *done)
337 {
338 	static const struct got_error *err = NULL;
339 	struct got_imsg_patch_hunk hdr;
340 	char	*line = NULL, ch;
341 	size_t	 linesize = 0;
342 	ssize_t	 linelen;
343 	long	 leftold, leftnew;
344 
345 	linelen = getline(&line, &linesize, fp);
346 	if (linelen == -1) {
347 		*done = 1;
348 		goto done;
349 	}
350 
351 	err = parse_hdr(line, done, &hdr);
352 	if (err)
353 		goto done;
354 	if (*done) {
355 		if (fseeko(fp, -linelen, SEEK_CUR) == -1)
356 			err = got_error_from_errno("fseeko");
357 		goto done;
358 	}
359 
360 	leftold = hdr.oldlines;
361 	leftnew = hdr.newlines;
362 
363 	while (leftold > 0 || leftnew > 0) {
364 		linelen = getline(&line, &linesize, fp);
365 		if (linelen == -1) {
366 			if (ferror(fp)) {
367 				err = got_error_from_errno("getline");
368 				goto done;
369 			}
370 
371 			/* trailing newlines may be chopped */
372 			if (leftold < 3 && leftnew < 3) {
373 				*done = 1;
374 				break;
375 			}
376 
377 			err = got_error(GOT_ERR_PATCH_TRUNCATED);
378 			goto done;
379 		}
380 		if (line[linelen - 1] == '\n')
381 			line[linelen - 1] = '\0';
382 
383 		/* usr.bin/patch allows '=' as context char */
384 		if (*line == '=')
385 			*line = ' ';
386 
387 		ch = *line;
388 		if (ch == '\t' || ch == '\0')
389 			ch = ' ';	/* the space got eaten */
390 
391 		switch (ch) {
392 		case '-':
393 			leftold--;
394 			break;
395 		case ' ':
396 			leftold--;
397 			leftnew--;
398 			break;
399 		case '+':
400 			leftnew--;
401 			break;
402 		default:
403 			err = got_error(GOT_ERR_PATCH_MALFORMED);
404 			goto done;
405 		}
406 
407 		if (leftold < 0 || leftnew < 0) {
408 			err = got_error(GOT_ERR_PATCH_MALFORMED);
409 			goto done;
410 		}
411 
412 		err = send_line(line);
413 		if (err)
414 			goto done;
415 
416 		if ((ch == '-' && leftold == 0) ||
417 		    (ch == '+' && leftnew == 0)) {
418 			err = peek_special_line(fp);
419 			if (err)
420 				goto done;
421 		}
422 	}
423 
424 done:
425 	free(line);
426 	return err;
427 }
428 
429 static const struct got_error *
430 read_patch(struct imsgbuf *ibuf, int fd)
431 {
432 	const struct got_error *err = NULL;
433 	FILE *fp;
434 	int patch_found = 0;
435 
436 	if ((fp = fdopen(fd, "r")) == NULL) {
437 		err = got_error_from_errno("fdopen");
438 		close(fd);
439 		return err;
440 	}
441 
442 	while (!feof(fp)) {
443 		int done = 0;
444 
445 		err = find_patch(&done, fp);
446 		if (err)
447 			goto done;
448 
449 		patch_found = 1;
450 
451 		while (!done) {
452 			err = parse_hunk(fp, &done);
453 			if (err)
454 				goto done;
455 		}
456 
457 		err = send_patch_done();
458 		if (err)
459 			goto done;
460 	}
461 
462 done:
463 	fclose(fp);
464 
465 	/* ignore trailing gibberish */
466 	if (err != NULL && err->code == GOT_ERR_NO_PATCH && patch_found)
467 		err = NULL;
468 
469 	return err;
470 }
471 
472 int
473 main(int argc, char **argv)
474 {
475 	const struct got_error *err = NULL;
476 	struct imsg imsg;
477 #if 0
478 	static int attached;
479 	while (!attached)
480 		sleep(1);
481 #endif
482 
483 	imsg_init(&ibuf, GOT_IMSG_FD_CHILD);
484 #ifndef PROFILE
485 	/* revoke access to most system calls */
486 	if (pledge("stdio recvfd", NULL) == -1) {
487 		err = got_error_from_errno("pledge");
488 		got_privsep_send_error(&ibuf, err);
489 		return 1;
490 	}
491 #endif
492 
493 	err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
494 	if (err)
495 		goto done;
496 	if (imsg.hdr.type != GOT_IMSG_PATCH_FILE || imsg.fd == -1) {
497 		err = got_error(GOT_ERR_PRIVSEP_MSG);
498 		goto done;
499 	}
500 
501 	err = read_patch(&ibuf, imsg.fd);
502 	if (err)
503 		goto done;
504 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH_EOF, 0, 0, -1,
505 	    NULL, 0) == -1) {
506 		err = got_error_from_errno("imsg_compose GOT_IMSG_PATCH_EOF");
507 		goto done;
508 	}
509 	err = got_privsep_flush_imsg(&ibuf);
510 done:
511 	imsg_free(&imsg);
512 	if (err != NULL) {
513 		got_privsep_send_error(&ibuf, err);
514 		err = NULL;
515 	}
516 	if (close(GOT_IMSG_FD_CHILD) == -1 && err == NULL)
517 		err = got_error_from_errno("close");
518 	if (err && err->code != GOT_ERR_PRIVSEP_PIPE)
519 		fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
520 	return err ? 1 : 0;
521 }