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Date:: Mon Mar 7 22:52:51 2022 UTC
Message:: portable: enable got-read-patch Allow the libexec helper, `got-read-patch` to be compiled, portably.
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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 <stdint.h>
46 #include <stdio.h>
47 #include <stdlib.h>
48 #include <string.h>
49 #include <unistd.h>
50 #include <imsg.h>
51 
52 #include "got_error.h"
53 #include "got_object.h"
54 
55 #include "got_compat.h"
56 
57 #include "got_lib_delta.h"
58 #include "got_lib_object.h"
59 #include "got_lib_privsep.h"
60 
61 struct imsgbuf ibuf;
62 
63 static const struct got_error *
64 send_patch(const char *oldname, const char *newname)
65 {
66 	struct got_imsg_patch p;
67 
68 	memset(&p, 0, sizeof(p));
69 
70 	if (oldname != NULL)
71 		strlcpy(p.old, oldname, sizeof(p.old));
72 	if (newname != NULL)
73 		strlcpy(p.new, newname, sizeof(p.new));
74 
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, int strip)
95 {
96 	char	*fullname, *t;
97 	int	 l, tab;
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 	t = strdup(at);
111 	if (t == NULL)
112 		return got_error_from_errno("strdup");
113 	*name = fullname = t;
114 	tab = strchr(t, '\t') != NULL;
115 
116 	/* strip off path components and NUL-terminate */
117 	for (l = strip;
118 	    *t != '\0' && ((tab && *t != '\t') || !isspace((unsigned char)*t));
119 	    ++t) {
120 		if (t[0] == '/' && t[1] != '/' && t[1] != '\0')
121 			if (--l >= 0)
122 				*name = t+1;
123 	}
124 	*t = '\0';
125 
126 	*name = strdup(*name);
127 	free(fullname);
128 	if (*name == NULL)
129 		return got_error_from_errno("strdup");
130 	return NULL;
131 }
132 
133 static const struct got_error *
134 find_patch(FILE *fp)
135 {
136 	const struct got_error *err = NULL;
137 	char	*old = NULL, *new = NULL;
138 	char	*line = NULL;
139 	size_t	 linesize = 0;
140 	ssize_t	 linelen;
141 	int	 create, git = 0;
142 
143 	while ((linelen = getline(&line, &linesize, fp)) != -1) {
144 		/*
145 		 * Ignore the Index name like GNU and larry' patch,
146 		 * we don't have to follow POSIX.
147 		 */
148 
149 		if (git && !strncmp(line, "--- a/", 6)) {
150 			free(old);
151 			err = filename(line+6, &old, 0);
152 		} else if (!strncmp(line, "--- ", 4)) {
153 			free(old);
154 			err = filename(line+4, &old, 0);
155 		} else if (git && !strncmp(line, "+++ b/", 6)) {
156 			free(new);
157 			err = filename(line+6, &new, 0);
158 		} else if (!strncmp(line, "+++ ", 4)) {
159 			free(new);
160 			err = filename(line+4, &new, 0);
161 		} else if (!strncmp(line, "diff --git a/", 13))
162 			git = 1;
163 
164 		if (err)
165 			break;
166 
167 		if (!strncmp(line, "@@ -", 4)) {
168 			create = !strncmp(line+4, "0,0", 3);
169 			if ((old == NULL && new == NULL) ||
170 			    (!create && old == NULL))
171 				err = got_error(GOT_ERR_PATCH_MALFORMED);
172 			else
173 				err = send_patch(old, new);
174 
175 			free(old);
176 			free(new);
177 
178 			if (err)
179 				break;
180 
181 			/* rewind to previous line */
182 			if (fseek(fp, linelen * -1, SEEK_CUR) == -1)
183 				err = got_error_from_errno("fseek");
184 			break;
185 		}
186 	}
187 
188 	free(line);
189 	if (ferror(fp) && err == NULL)
190 		err = got_error_from_errno("getline");
191 	if (feof(fp) && err == NULL)
192 		err = got_error(GOT_ERR_NO_PATCH);
193 	return err;
194 }
195 
196 static const struct got_error *
197 strtolnum(char **str, long *n)
198 {
199 	char		*p, c;
200 	const char	*errstr;
201 
202 	for (p = *str; isdigit((unsigned char)*p); ++p)
203 		/* nop */;
204 
205 	c = *p;
206 	*p = '\0';
207 
208 	*n = strtonum(*str, 0, LONG_MAX, &errstr);
209 	if (errstr != NULL)
210 		return got_error(GOT_ERR_PATCH_MALFORMED);
211 
212 	*p = c;
213 	*str = p;
214 	return NULL;
215 }
216 
217 static const struct got_error *
218 parse_hdr(char *s, int *ok, struct got_imsg_patch_hunk *hdr)
219 {
220 	static const struct got_error *err = NULL;
221 
222 	*ok = 1;
223 	if (strncmp(s, "@@ -", 4)) {
224 		*ok = 0;
225 		return NULL;
226 	}
227 
228 	s += 4;
229 	if (!*s)
230 		return NULL;
231 	err = strtolnum(&s, &hdr->oldfrom);
232 	if (err)
233 		return err;
234 	if (*s == ',') {
235 		s++;
236 		err = strtolnum(&s, &hdr->oldlines);
237 		if (err)
238 			return err;
239 	} else
240 		hdr->oldlines = 1;
241 
242 	if (*s == ' ')
243 		s++;
244 
245 	if (*s != '+' || !*++s)
246 		return got_error(GOT_ERR_PATCH_MALFORMED);
247 	err = strtolnum(&s, &hdr->newfrom);
248 	if (err)
249 		return err;
250 	if (*s == ',') {
251 		s++;
252 		err = strtolnum(&s, &hdr->newlines);
253 		if (err)
254 			return err;
255 	} else
256 		hdr->newlines = 1;
257 
258 	if (*s == ' ')
259 		s++;
260 
261 	if (*s != '@')
262 		return got_error(GOT_ERR_PATCH_MALFORMED);
263 
264 	if (hdr->oldfrom >= LONG_MAX - hdr->oldlines ||
265 	    hdr->newfrom >= LONG_MAX - hdr->newlines ||
266 	    /* not so sure about this one */
267 	    hdr->oldlines >= LONG_MAX - hdr->newlines - 1)
268 		return got_error(GOT_ERR_PATCH_MALFORMED);
269 
270 	if (hdr->oldlines == 0) {
271 		/* larry says to "do append rather than insert"; I don't
272 		 * quite get it, but i trust him.
273 		 */
274 		hdr->oldfrom++;
275 	}
276 
277 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH_HUNK, 0, 0, -1,
278 	    hdr, sizeof(*hdr)) == -1)
279 		return got_error_from_errno(
280 		    "imsg_compose GOT_IMSG_PATCH_HUNK");
281 	return NULL;
282 }
283 
284 static const struct got_error *
285 send_line(const char *line)
286 {
287 	static const struct got_error *err = NULL;
288 	char *p = NULL;
289 
290 	if (*line != '+' && *line != '-' && *line != ' ') {
291 		if (asprintf(&p, " %s", line) == -1)
292 			return got_error_from_errno("asprintf");
293 		line = p;
294 	}
295 
296 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH_LINE, 0, 0, -1,
297 	    line, strlen(line)+1) == -1)
298 		err = got_error_from_errno(
299 		    "imsg_compose GOT_IMSG_PATCH_LINE");
300 
301 	free(p);
302 	return err;
303 }
304 
305 static const struct got_error *
306 parse_hunk(FILE *fp, int *ok)
307 {
308 	static const struct got_error *err = NULL;
309 	struct got_imsg_patch_hunk hdr;
310 	char	*line = NULL, ch;
311 	size_t	 linesize = 0;
312 	ssize_t	 linelen;
313 	long	 leftold, leftnew;
314 
315 	linelen = getline(&line, &linesize, fp);
316 	if (linelen == -1) {
317 		*ok = 0;
318 		goto done;
319 	}
320 
321 	err = parse_hdr(line, ok, &hdr);
322 	if (err)
323 		goto done;
324 	if (!*ok) {
325 		if (fseek(fp, linelen * -1, SEEK_CUR) == -1)
326 			err = got_error_from_errno("fseek");
327 		goto done;
328 	}
329 
330 	leftold = hdr.oldlines;
331 	leftnew = hdr.newlines;
332 
333 	while (leftold > 0 || leftnew > 0) {
334 		linelen = getline(&line, &linesize, fp);
335 		if (linelen == -1) {
336 			if (ferror(fp)) {
337 				err = got_error_from_errno("getline");
338 				goto done;
339 			}
340 
341 			/* trailing newlines may be chopped */
342 			if (leftold < 3 && leftnew < 3) {
343 				*ok = 0;
344 				break;
345 			}
346 
347 			err = got_error(GOT_ERR_PATCH_TRUNCATED);
348 			goto done;
349 		}
350 
351 		/* usr.bin/patch allows '=' as context char */
352 		if (*line == '=')
353 			*line = ' ';
354 
355 		ch = *line;
356 		if (ch == '\t' || ch == '\n')
357 			ch = ' ';	/* the space got eaten */
358 
359 		switch (ch) {
360 		case '-':
361 			leftold--;
362 			break;
363 		case ' ':
364 			leftold--;
365 			leftnew--;
366 			break;
367 		case '+':
368 			leftnew--;
369 			break;
370 		default:
371 			err = got_error(GOT_ERR_PATCH_MALFORMED);
372 			goto done;
373 		}
374 
375 		if (leftold < 0 || leftnew < 0) {
376 			err = got_error(GOT_ERR_PATCH_MALFORMED);
377 			goto done;
378 		}
379 
380 		err = send_line(line);
381 		if (err)
382 			goto done;
383 	}
384 
385 done:
386 	free(line);
387 	return err;
388 }
389 
390 static const struct got_error *
391 read_patch(struct imsgbuf *ibuf, int fd)
392 {
393 	const struct got_error *err = NULL;
394 	FILE *fp;
395 	int ok, patch_found = 0;
396 
397 	if ((fp = fdopen(fd, "r")) == NULL) {
398 		err = got_error_from_errno("fdopen");
399 		close(fd);
400 		return err;
401 	}
402 
403 	while (!feof(fp)) {
404 		err = find_patch(fp);
405 		if (err)
406 			goto done;
407 
408 		patch_found = 1;
409 		for (;;) {
410 			err = parse_hunk(fp, &ok);
411 			if (err)
412 				goto done;
413 			if (!ok) {
414 				err = send_patch_done();
415 				if (err)
416 					goto done;
417 				break;
418 			}
419 		}
420 	}
421 
422 done:
423 	fclose(fp);
424 
425 	/* ignore trailing gibberish */
426 	if (err != NULL && err->code == GOT_ERR_NO_PATCH && patch_found)
427 		err = NULL;
428 
429 	return err;
430 }
431 
432 int
433 main(int argc, char **argv)
434 {
435 	const struct got_error *err = NULL;
436 	struct imsg imsg;
437 #if 0
438 	static int attached;
439 	while (!attached)
440 		sleep(1);
441 #endif
442 
443 	imsg_init(&ibuf, GOT_IMSG_FD_CHILD);
444 #ifndef PROFILE
445 	/* revoke access to most system calls */
446 	if (pledge("stdio recvfd", NULL) == -1) {
447 		err = got_error_from_errno("pledge");
448 		got_privsep_send_error(&ibuf, err);
449 		return 1;
450 	}
451 #endif
452 
453 	err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
454 	if (err)
455 		goto done;
456 	if (imsg.hdr.type != GOT_IMSG_PATCH_FILE || imsg.fd == -1) {
457 		err = got_error(GOT_ERR_PRIVSEP_MSG);
458 		goto done;
459 	}
460 
461 	err = read_patch(&ibuf, imsg.fd);
462 	if (err)
463 		goto done;
464 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH_EOF, 0, 0, -1,
465 	    NULL, 0) == -1) {
466 		err = got_error_from_errno("imsg_compose GOT_IMSG_PATCH_EOF");
467 		goto done;
468 	}
469 	err = got_privsep_flush_imsg(&ibuf);
470 done:
471 	imsg_free(&imsg);
472 	if (err != NULL) {
473 		got_privsep_send_error(&ibuf, err);
474 		err = NULL;
475 	}
476 	if (close(GOT_IMSG_FD_CHILD) == -1 && err == NULL)
477 		err = got_error_from_errno("close");
478 	if (err && err->code != GOT_ERR_PRIVSEP_PIPE)
479 		fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
480 	return err ? 1 : 0;
481 }