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 HAVE_VASPRINTF
33/* If we have vasprintf, we need to define this before we include stdio.h. */
34#define _GNU_SOURCE
35#endif
36
37#include <sys/types.h>
38
39#ifdef HAVE_SYS_TIME_H
40#include <sys/time.h>
41#endif
42
43#ifdef HAVE_SYS_IOCTL_H
44#include <sys/ioctl.h>
45#endif
46
47#include <errno.h>
48#include <stdio.h>
49#include <stdlib.h>
50#include <string.h>
51#ifdef HAVE_STDARG_H
52#include <stdarg.h>
53#endif
54#ifdef HAVE_UNISTD_H
55#include <unistd.h>
56#endif
57
58#include "event.h"
59
60struct evbuffer *
61evbuffer_new(void)
62{
63	struct evbuffer *buffer;
64
65	buffer = calloc(1, sizeof(struct evbuffer));
66
67	return (buffer);
68}
69
70void
71evbuffer_free(struct evbuffer *buffer)
72{
73	if (buffer->orig_buffer != NULL)
74		free(buffer->orig_buffer);
75	free(buffer);
76}
77
78/*
79 * This is a destructive add.  The data from one buffer moves into
80 * the other buffer.
81 */
82
83#define SWAP(x,y) do { \
84	(x)->buffer = (y)->buffer; \
85	(x)->orig_buffer = (y)->orig_buffer; \
86	(x)->misalign = (y)->misalign; \
87	(x)->totallen = (y)->totallen; \
88	(x)->off = (y)->off; \
89} while (0)
90
91int
92evbuffer_add_buffer(struct evbuffer *outbuf, struct evbuffer *inbuf)
93{
94	int res;
95
96	/* Short cut for better performance */
97	if (outbuf->off == 0) {
98		struct evbuffer tmp;
99		size_t oldoff = inbuf->off;
100
101		/* Swap them directly */
102		SWAP(&tmp, outbuf);
103		SWAP(outbuf, inbuf);
104		SWAP(inbuf, &tmp);
105
106		/*
107		 * Optimization comes with a price; we need to notify the
108		 * buffer if necessary of the changes. oldoff is the amount
109		 * of data that we tranfered from inbuf to outbuf
110		 */
111		if (inbuf->off != oldoff && inbuf->cb != NULL)
112			(*inbuf->cb)(inbuf, oldoff, inbuf->off, inbuf->cbarg);
113		if (oldoff && outbuf->cb != NULL)
114			(*outbuf->cb)(outbuf, 0, oldoff, outbuf->cbarg);
115
116		return (0);
117	}
118
119	res = evbuffer_add(outbuf, inbuf->buffer, inbuf->off);
120	if (res == 0) {
121		/* We drain the input buffer on success */
122		evbuffer_drain(inbuf, inbuf->off);
123	}
124
125	return (res);
126}
127
128int
129evbuffer_add_vprintf(struct evbuffer *buf, const char *fmt, va_list ap)
130{
131	char *buffer;
132	size_t space;
133	size_t oldoff = buf->off;
134	int sz;
135	va_list aq;
136
137	for (;;) {
138		buffer = (char *)buf->buffer + buf->off;
139		space = buf->totallen - buf->misalign - buf->off;
140
141#ifndef va_copy
142#define	va_copy(dst, src)	memcpy(&(dst), &(src), sizeof(va_list))
143#endif
144		va_copy(aq, ap);
145
146#ifdef WIN32
147		sz = vsnprintf(buffer, space - 1, fmt, aq);
148		buffer[space - 1] = '\0';
149#else
150		sz = vsnprintf(buffer, space, fmt, aq);
151#endif
152
153		va_end(aq);
154
155		if (sz == -1)
156			return (-1);
157		if (sz < space) {
158			buf->off += sz;
159			if (buf->cb != NULL)
160				(*buf->cb)(buf, oldoff, buf->off, buf->cbarg);
161			return (sz);
162		}
163		if (evbuffer_expand(buf, sz + 1) == -1)
164			return (-1);
165
166	}
167	/* NOTREACHED */
168}
169
170int
171evbuffer_add_printf(struct evbuffer *buf, const char *fmt, ...)
172{
173	int res = -1;
174	va_list ap;
175
176	va_start(ap, fmt);
177	res = evbuffer_add_vprintf(buf, fmt, ap);
178	va_end(ap);
179
180	return (res);
181}
182
183/* Reads data from an event buffer and drains the bytes read */
184
185int
186evbuffer_remove(struct evbuffer *buf, void *data, size_t datlen)
187{
188	size_t nread = datlen;
189	if (nread >= buf->off)
190		nread = buf->off;
191
192	memcpy(data, buf->buffer, nread);
193	evbuffer_drain(buf, nread);
194
195	return (nread);
196}
197
198/*
199 * Reads a line terminated by either '\r\n', '\n\r' or '\r' or '\n'.
200 * The returned buffer needs to be freed by the called.
201 */
202
203char *
204evbuffer_readline(struct evbuffer *buffer)
205{
206	u_char *data = EVBUFFER_DATA(buffer);
207	size_t len = EVBUFFER_LENGTH(buffer);
208	char *line;
209	unsigned int i;
210
211	for (i = 0; i < len; i++) {
212		if (data[i] == '\r' || data[i] == '\n')
213			break;
214	}
215
216	if (i == len)
217		return (NULL);
218
219	if ((line = malloc(i + 1)) == NULL) {
220		fprintf(stderr, "%s: out of memory\n", __func__);
221		evbuffer_drain(buffer, i);
222		return (NULL);
223	}
224
225	memcpy(line, data, i);
226	line[i] = '\0';
227
228	/*
229	 * Some protocols terminate a line with '\r\n', so check for
230	 * that, too.
231	 */
232	if ( i < len - 1 ) {
233		char fch = data[i], sch = data[i+1];
234
235		/* Drain one more character if needed */
236		if ( (sch == '\r' || sch == '\n') && sch != fch )
237			i += 1;
238	}
239
240	evbuffer_drain(buffer, i + 1);
241
242	return (line);
243}
244
245/* Adds data to an event buffer */
246
247static inline void
248evbuffer_align(struct evbuffer *buf)
249{
250	memmove(buf->orig_buffer, buf->buffer, buf->off);
251	buf->buffer = buf->orig_buffer;
252	buf->misalign = 0;
253}
254
255/* Expands the available space in the event buffer to at least datlen */
256
257int
258evbuffer_expand(struct evbuffer *buf, size_t datlen)
259{
260	size_t need = buf->misalign + buf->off + datlen;
261
262	/* If we can fit all the data, then we don't have to do anything */
263	if (buf->totallen >= need)
264		return (0);
265
266	/*
267	 * If the misalignment fulfills our data needs, we just force an
268	 * alignment to happen.  Afterwards, we have enough space.
269	 */
270	if (buf->misalign >= datlen) {
271		evbuffer_align(buf);
272	} else {
273		void *newbuf;
274		size_t length = buf->totallen;
275
276		if (length < 256)
277			length = 256;
278		while (length < need)
279			length <<= 1;
280
281		if (buf->orig_buffer != buf->buffer)
282			evbuffer_align(buf);
283		if ((newbuf = realloc(buf->buffer, length)) == NULL)
284			return (-1);
285
286		buf->orig_buffer = buf->buffer = newbuf;
287		buf->totallen = length;
288	}
289
290	return (0);
291}
292
293int
294evbuffer_add(struct evbuffer *buf, const void *data, size_t datlen)
295{
296	size_t need = buf->misalign + buf->off + datlen;
297	size_t oldoff = buf->off;
298
299	if (buf->totallen < need) {
300		if (evbuffer_expand(buf, datlen) == -1)
301			return (-1);
302	}
303
304	memcpy(buf->buffer + buf->off, data, datlen);
305	buf->off += datlen;
306
307	if (datlen && buf->cb != NULL)
308		(*buf->cb)(buf, oldoff, buf->off, buf->cbarg);
309
310	return (0);
311}
312
313void
314evbuffer_drain(struct evbuffer *buf, size_t len)
315{
316	size_t oldoff = buf->off;
317
318	if (len >= buf->off) {
319		buf->off = 0;
320		buf->buffer = buf->orig_buffer;
321		buf->misalign = 0;
322		goto done;
323	}
324
325	buf->buffer += len;
326	buf->misalign += len;
327
328	buf->off -= len;
329
330 done:
331	/* Tell someone about changes in this buffer */
332	if (buf->off != oldoff && buf->cb != NULL)
333		(*buf->cb)(buf, oldoff, buf->off, buf->cbarg);
334
335}
336
337/*
338 * Reads data from a file descriptor into a buffer.
339 */
340
341#define EVBUFFER_MAX_READ	4096
342
343int
344evbuffer_read(struct evbuffer *buf, int fd, int howmuch)
345{
346	u_char *p;
347	size_t oldoff = buf->off;
348	int n = EVBUFFER_MAX_READ;
349#ifdef WIN32
350	DWORD dwBytesRead;
351#endif
352
353#ifdef FIONREAD
354	if (ioctl(fd, FIONREAD, &n) == -1 || n == 0) {
355		n = EVBUFFER_MAX_READ;
356	} else if (n > EVBUFFER_MAX_READ && n > howmuch) {
357		/*
358		 * It's possible that a lot of data is available for
359		 * reading.  We do not want to exhaust resources
360		 * before the reader has a chance to do something
361		 * about it.  If the reader does not tell us how much
362		 * data we should read, we artifically limit it.
363		 */
364		if (n > buf->totallen << 2)
365			n = buf->totallen << 2;
366		if (n < EVBUFFER_MAX_READ)
367			n = EVBUFFER_MAX_READ;
368	}
369#endif
370	if (howmuch < 0 || howmuch > n)
371		howmuch = n;
372
373	/* If we don't have FIONREAD, we might waste some space here */
374	if (evbuffer_expand(buf, howmuch) == -1)
375		return (-1);
376
377	/* We can append new data at this point */
378	p = buf->buffer + buf->off;
379
380#ifndef WIN32
381	n = read(fd, p, howmuch);
382	if (n == -1)
383		return (-1);
384	if (n == 0)
385		return (0);
386#else
387	n = ReadFile((HANDLE)fd, p, howmuch, &dwBytesRead, NULL);
388	if (n == 0)
389		return (-1);
390	if (dwBytesRead == 0)
391		return (0);
392	n = dwBytesRead;
393#endif
394
395	buf->off += n;
396
397	/* Tell someone about changes in this buffer */
398	if (buf->off != oldoff && buf->cb != NULL)
399		(*buf->cb)(buf, oldoff, buf->off, buf->cbarg);
400
401	return (n);
402}
403
404int
405evbuffer_write(struct evbuffer *buffer, int fd)
406{
407	int n;
408#ifdef WIN32
409	DWORD dwBytesWritten;
410#endif
411
412#ifndef WIN32
413	n = write(fd, buffer->buffer, buffer->off);
414	if (n == -1)
415		return (-1);
416	if (n == 0)
417		return (0);
418#else
419	n = WriteFile((HANDLE)fd, buffer->buffer, buffer->off, &dwBytesWritten, NULL);
420	if (n == 0)
421		return (-1);
422	if (dwBytesWritten == 0)
423		return (0);
424	n = dwBytesWritten;
425#endif
426	evbuffer_drain(buffer, n);
427
428	return (n);
429}
430
431u_char *
432evbuffer_find(struct evbuffer *buffer, const u_char *what, size_t len)
433{
434	size_t remain = buffer->off;
435	u_char *search = buffer->buffer;
436	u_char *p;
437
438	while ((p = memchr(search, *what, remain)) != NULL) {
439		remain = buffer->off - (size_t)(search - buffer->buffer);
440		if (remain < len)
441			break;
442		if (memcmp(p, what, len) == 0)
443			return (p);
444		search = p + 1;
445	}
446
447	return (NULL);
448}
449
450void evbuffer_setcb(struct evbuffer *buffer,
451    void (*cb)(struct evbuffer *, size_t, size_t, void *),
452    void *cbarg)
453{
454	buffer->cb = cb;
455	buffer->cbarg = cbarg;
456}
457