xref: /openbsd/lib/libevent/buffer.c (revision 898184e3) 
1 /*	$OpenBSD: buffer.c,v 1.19 2010/07/17 17:16:47 chl Exp $	*/
2 
3 /*
4  * Copyright (c) 2002, 2003 Niels Provos <provos@citi.umich.edu>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. The name of the author may not be used to endorse or promote products
16  *    derived from this software without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28  */
29 
30 #ifdef HAVE_CONFIG_H
31 #include "config.h"
32 #endif
33 
34 #ifdef WIN32
35 #include <winsock2.h>
36 #include <windows.h>
37 #endif
38 
39 #ifdef HAVE_VASPRINTF
40 /* If we have vasprintf, we need to define this before we include stdio.h. */
41 #define _GNU_SOURCE
42 #endif
43 
44 #include <sys/types.h>
45 
46 #ifdef HAVE_SYS_TIME_H
47 #include <sys/time.h>
48 #endif
49 
50 #ifdef HAVE_SYS_IOCTL_H
51 #include <sys/ioctl.h>
52 #endif
53 
54 #include <assert.h>
55 #include <errno.h>
56 #include <stdio.h>
57 #include <stdlib.h>
58 #include <string.h>
59 #ifdef HAVE_STDARG_H
60 #include <stdarg.h>
61 #endif
62 #ifdef HAVE_UNISTD_H
63 #include <unistd.h>
64 #endif
65 
66 #include "event.h"
67 #include "evutil.h"
68 #include "./log.h"
69 
70 struct evbuffer *
71 evbuffer_new(void)
72 {
73 	struct evbuffer *buffer;
74 
75 	buffer = calloc(1, sizeof(struct evbuffer));
76 
77 	return (buffer);
78 }
79 
80 void
81 evbuffer_free(struct evbuffer *buffer)
82 {
83 	if (buffer->orig_buffer != NULL)
84 		free(buffer->orig_buffer);
85 	free(buffer);
86 }
87 
88 /*
89  * This is a destructive add.  The data from one buffer moves into
90  * the other buffer.
91  */
92 
93 #define SWAP(x,y) do { \
94 	(x)->buffer = (y)->buffer; \
95 	(x)->orig_buffer = (y)->orig_buffer; \
96 	(x)->misalign = (y)->misalign; \
97 	(x)->totallen = (y)->totallen; \
98 	(x)->off = (y)->off; \
99 } while (0)
100 
101 int
102 evbuffer_add_buffer(struct evbuffer *outbuf, struct evbuffer *inbuf)
103 {
104 	int res;
105 
106 	/* Short cut for better performance */
107 	if (outbuf->off == 0) {
108 		struct evbuffer tmp;
109 		size_t oldoff = inbuf->off;
110 
111 		/* Swap them directly */
112 		SWAP(&tmp, outbuf);
113 		SWAP(outbuf, inbuf);
114 		SWAP(inbuf, &tmp);
115 
116 		/*
117 		 * Optimization comes with a price; we need to notify the
118 		 * buffer if necessary of the changes. oldoff is the amount
119 		 * of data that we transferred from inbuf to outbuf
120 		 */
121 		if (inbuf->off != oldoff && inbuf->cb != NULL)
122 			(*inbuf->cb)(inbuf, oldoff, inbuf->off, inbuf->cbarg);
123 		if (oldoff && outbuf->cb != NULL)
124 			(*outbuf->cb)(outbuf, 0, oldoff, outbuf->cbarg);
125 
126 		return (0);
127 	}
128 
129 	res = evbuffer_add(outbuf, inbuf->buffer, inbuf->off);
130 	if (res == 0) {
131 		/* We drain the input buffer on success */
132 		evbuffer_drain(inbuf, inbuf->off);
133 	}
134 
135 	return (res);
136 }
137 
138 int
139 evbuffer_add_vprintf(struct evbuffer *buf, const char *fmt, va_list ap)
140 {
141 	char *buffer;
142 	size_t space;
143 	size_t oldoff = buf->off;
144 	int sz;
145 	va_list aq;
146 
147 	/* make sure that at least some space is available */
148 	evbuffer_expand(buf, 64);
149 	for (;;) {
150 		size_t used = buf->misalign + buf->off;
151 		buffer = (char *)buf->buffer + buf->off;
152 		assert(buf->totallen >= used);
153 		space = buf->totallen - used;
154 
155 #ifndef va_copy
156 #define	va_copy(dst, src)	memcpy(&(dst), &(src), sizeof(va_list))
157 #endif
158 		va_copy(aq, ap);
159 
160 		sz = evutil_vsnprintf(buffer, space, fmt, aq);
161 
162 		va_end(aq);
163 
164 		if (sz < 0)
165 			return (-1);
166 		if ((size_t)sz < space) {
167 			buf->off += sz;
168 			if (buf->cb != NULL)
169 				(*buf->cb)(buf, oldoff, buf->off, buf->cbarg);
170 			return (sz);
171 		}
172 		if (evbuffer_expand(buf, sz + 1) == -1)
173 			return (-1);
174 
175 	}
176 	/* NOTREACHED */
177 }
178 
179 int
180 evbuffer_add_printf(struct evbuffer *buf, const char *fmt, ...)
181 {
182 	int res = -1;
183 	va_list ap;
184 
185 	va_start(ap, fmt);
186 	res = evbuffer_add_vprintf(buf, fmt, ap);
187 	va_end(ap);
188 
189 	return (res);
190 }
191 
192 /* Reads data from an event buffer and drains the bytes read */
193 
194 int
195 evbuffer_remove(struct evbuffer *buf, void *data, size_t datlen)
196 {
197 	size_t nread = datlen;
198 	if (nread >= buf->off)
199 		nread = buf->off;
200 
201 	memcpy(data, buf->buffer, nread);
202 	evbuffer_drain(buf, nread);
203 
204 	return (nread);
205 }
206 
207 /*
208  * Reads a line terminated by either '\r\n', '\n\r' or '\r' or '\n'.
209  * The returned buffer needs to be freed by the called.
210  */
211 
212 char *
213 evbuffer_readline(struct evbuffer *buffer)
214 {
215 	u_char *data = EVBUFFER_DATA(buffer);
216 	size_t len = EVBUFFER_LENGTH(buffer);
217 	char *line;
218 	unsigned int i;
219 
220 	for (i = 0; i < len; i++) {
221 		if (data[i] == '\r' || data[i] == '\n')
222 			break;
223 	}
224 
225 	if (i == len)
226 		return (NULL);
227 
228 	if ((line = malloc(i + 1)) == NULL) {
229 		fprintf(stderr, "%s: out of memory\n", __func__);
230 		return (NULL);
231 	}
232 
233 	memcpy(line, data, i);
234 	line[i] = '\0';
235 
236 	/*
237 	 * Some protocols terminate a line with '\r\n', so check for
238 	 * that, too.
239 	 */
240 	if ( i < len - 1 ) {
241 		char fch = data[i], sch = data[i+1];
242 
243 		/* Drain one more character if needed */
244 		if ( (sch == '\r' || sch == '\n') && sch != fch )
245 			i += 1;
246 	}
247 
248 	evbuffer_drain(buffer, i + 1);
249 
250 	return (line);
251 }
252 
253 
254 char *
255 evbuffer_readln(struct evbuffer *buffer, size_t *n_read_out,
256 		enum evbuffer_eol_style eol_style)
257 {
258 	u_char *data = EVBUFFER_DATA(buffer);
259 	u_char *start_of_eol, *end_of_eol;
260 	size_t len = EVBUFFER_LENGTH(buffer);
261 	char *line;
262 	unsigned int i, n_to_copy, n_to_drain;
263 
264 	if (n_read_out)
265 		*n_read_out = 0;
266 
267 	/* depending on eol_style, set start_of_eol to the first character
268 	 * in the newline, and end_of_eol to one after the last character. */
269 	switch (eol_style) {
270 	case EVBUFFER_EOL_ANY:
271 		for (i = 0; i < len; i++) {
272 			if (data[i] == '\r' || data[i] == '\n')
273 				break;
274 		}
275 		if (i == len)
276 			return (NULL);
277 		start_of_eol = data+i;
278 		++i;
279 		for ( ; i < len; i++) {
280 			if (data[i] != '\r' && data[i] != '\n')
281 				break;
282 		}
283 		end_of_eol = data+i;
284 		break;
285 	case EVBUFFER_EOL_CRLF:
286 		end_of_eol = memchr(data, '\n', len);
287 		if (!end_of_eol)
288 			return (NULL);
289 		if (end_of_eol > data && *(end_of_eol-1) == '\r')
290 			start_of_eol = end_of_eol - 1;
291 		else
292 			start_of_eol = end_of_eol;
293 		end_of_eol++; /*point to one after the LF. */
294 		break;
295 	case EVBUFFER_EOL_CRLF_STRICT: {
296 		u_char *cp = data;
297 		while ((cp = memchr(cp, '\r', len-(cp-data)))) {
298 			if (cp < data+len-1 && *(cp+1) == '\n')
299 				break;
300 			if (++cp >= data+len) {
301 				cp = NULL;
302 				break;
303 			}
304 		}
305 		if (!cp)
306 			return (NULL);
307 		start_of_eol = cp;
308 		end_of_eol = cp+2;
309 		break;
310 	}
311 	case EVBUFFER_EOL_LF:
312 		start_of_eol = memchr(data, '\n', len);
313 		if (!start_of_eol)
314 			return (NULL);
315 		end_of_eol = start_of_eol + 1;
316 		break;
317 	default:
318 		return (NULL);
319 	}
320 
321 	n_to_copy = start_of_eol - data;
322 	n_to_drain = end_of_eol - data;
323 
324 	if ((line = malloc(n_to_copy+1)) == NULL) {
325 		event_warn("%s: out of memory\n", __func__);
326 		return (NULL);
327 	}
328 
329 	memcpy(line, data, n_to_copy);
330 	line[n_to_copy] = '\0';
331 
332 	evbuffer_drain(buffer, n_to_drain);
333 	if (n_read_out)
334 		*n_read_out = (size_t)n_to_copy;
335 
336 	return (line);
337 }
338 
339 /* Adds data to an event buffer */
340 
341 static void
342 evbuffer_align(struct evbuffer *buf)
343 {
344 	memmove(buf->orig_buffer, buf->buffer, buf->off);
345 	buf->buffer = buf->orig_buffer;
346 	buf->misalign = 0;
347 }
348 
349 /* Expands the available space in the event buffer to at least datlen */
350 
351 int
352 evbuffer_expand(struct evbuffer *buf, size_t datlen)
353 {
354 	size_t need = buf->misalign + buf->off + datlen;
355 
356 	/* If we can fit all the data, then we don't have to do anything */
357 	if (buf->totallen >= need)
358 		return (0);
359 
360 	/*
361 	 * If the misalignment fulfills our data needs, we just force an
362 	 * alignment to happen.  Afterwards, we have enough space.
363 	 */
364 	if (buf->misalign >= datlen) {
365 		evbuffer_align(buf);
366 	} else {
367 		void *newbuf;
368 		size_t length = buf->totallen;
369 
370 		if (length < 256)
371 			length = 256;
372 		while (length < need)
373 			length <<= 1;
374 
375 		if (buf->orig_buffer != buf->buffer)
376 			evbuffer_align(buf);
377 		if ((newbuf = realloc(buf->buffer, length)) == NULL)
378 			return (-1);
379 
380 		buf->orig_buffer = buf->buffer = newbuf;
381 		buf->totallen = length;
382 	}
383 
384 	return (0);
385 }
386 
387 int
388 evbuffer_add(struct evbuffer *buf, const void *data, size_t datlen)
389 {
390 	size_t need = buf->misalign + buf->off + datlen;
391 	size_t oldoff = buf->off;
392 
393 	if (buf->totallen < need) {
394 		if (evbuffer_expand(buf, datlen) == -1)
395 			return (-1);
396 	}
397 
398 	memcpy(buf->buffer + buf->off, data, datlen);
399 	buf->off += datlen;
400 
401 	if (datlen && buf->cb != NULL)
402 		(*buf->cb)(buf, oldoff, buf->off, buf->cbarg);
403 
404 	return (0);
405 }
406 
407 void
408 evbuffer_drain(struct evbuffer *buf, size_t len)
409 {
410 	size_t oldoff = buf->off;
411 
412 	if (len >= buf->off) {
413 		buf->off = 0;
414 		buf->buffer = buf->orig_buffer;
415 		buf->misalign = 0;
416 		goto done;
417 	}
418 
419 	buf->buffer += len;
420 	buf->misalign += len;
421 
422 	buf->off -= len;
423 
424  done:
425 	/* Tell someone about changes in this buffer */
426 	if (buf->off != oldoff && buf->cb != NULL)
427 		(*buf->cb)(buf, oldoff, buf->off, buf->cbarg);
428 
429 }
430 
431 /*
432  * Reads data from a file descriptor into a buffer.
433  */
434 
435 #define EVBUFFER_MAX_READ	4096
436 
437 int
438 evbuffer_read(struct evbuffer *buf, int fd, int howmuch)
439 {
440 	u_char *p;
441 	size_t oldoff = buf->off;
442 	int n = EVBUFFER_MAX_READ;
443 
444 #if defined(FIONREAD)
445 #ifdef WIN32
446 	long lng = n;
447 	if (ioctlsocket(fd, FIONREAD, &lng) == -1 || (n=lng) <= 0) {
448 #else
449 	if (ioctl(fd, FIONREAD, &n) == -1 || n <= 0) {
450 #endif
451 		n = EVBUFFER_MAX_READ;
452 	} else if (n > EVBUFFER_MAX_READ && n > howmuch) {
453 		/*
454 		 * It's possible that a lot of data is available for
455 		 * reading.  We do not want to exhaust resources
456 		 * before the reader has a chance to do something
457 		 * about it.  If the reader does not tell us how much
458 		 * data we should read, we artifically limit it.
459 		 */
460 		if ((size_t)n > buf->totallen << 2)
461 			n = buf->totallen << 2;
462 		if (n < EVBUFFER_MAX_READ)
463 			n = EVBUFFER_MAX_READ;
464 	}
465 #endif
466 	if (howmuch < 0 || howmuch > n)
467 		howmuch = n;
468 
469 	/* If we don't have FIONREAD, we might waste some space here */
470 	if (evbuffer_expand(buf, howmuch) == -1)
471 		return (-1);
472 
473 	/* We can append new data at this point */
474 	p = buf->buffer + buf->off;
475 
476 #ifndef WIN32
477 	n = read(fd, p, howmuch);
478 #else
479 	n = recv(fd, p, howmuch, 0);
480 #endif
481 	if (n == -1)
482 		return (-1);
483 	if (n == 0)
484 		return (0);
485 
486 	buf->off += n;
487 
488 	/* Tell someone about changes in this buffer */
489 	if (buf->off != oldoff && buf->cb != NULL)
490 		(*buf->cb)(buf, oldoff, buf->off, buf->cbarg);
491 
492 	return (n);
493 }
494 
495 int
496 evbuffer_write(struct evbuffer *buffer, int fd)
497 {
498 	int n;
499 
500 #ifndef WIN32
501 	n = write(fd, buffer->buffer, buffer->off);
502 #else
503 	n = send(fd, buffer->buffer, buffer->off, 0);
504 #endif
505 	if (n == -1)
506 		return (-1);
507 	if (n == 0)
508 		return (0);
509 	evbuffer_drain(buffer, n);
510 
511 	return (n);
512 }
513 
514 u_char *
515 evbuffer_find(struct evbuffer *buffer, const u_char *what, size_t len)
516 {
517 	u_char *search = buffer->buffer, *end = search + buffer->off;
518 	u_char *p;
519 
520 	while (search < end &&
521 	    (p = memchr(search, *what, end - search)) != NULL) {
522 		if (p + len > end)
523 			break;
524 		if (memcmp(p, what, len) == 0)
525 			return (p);
526 		search = p + 1;
527 	}
528 
529 	return (NULL);
530 }
531 
532 void evbuffer_setcb(struct evbuffer *buffer,
533     void (*cb)(struct evbuffer *, size_t, size_t, void *),
534     void *cbarg)
535 {
536 	buffer->cb = cb;
537 	buffer->cbarg = cbarg;
538 }
539