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