1/* $Id: imsg-buffer.c,v 1.5 2012/01/20 14:08:04 joerg Exp $ */
2/*	$OpenBSD: imsg-buffer.c,v 1.3 2010/05/26 13:56:07 nicm Exp $	*/
3
4/*
5 * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
6 *
7 * Permission to use, copy, modify, and distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 */
19
20#include <sys/param.h>
21#include <sys/socket.h>
22#include <sys/uio.h>
23
24#include <errno.h>
25#include <stdlib.h>
26#include <string.h>
27#include <unistd.h>
28
29#include "tmux.h"
30
31int	ibuf_realloc(struct ibuf *, size_t);
32void	ibuf_enqueue(struct msgbuf *, struct ibuf *);
33void	ibuf_dequeue(struct msgbuf *, struct ibuf *);
34
35struct ibuf *
36ibuf_open(size_t len)
37{
38	struct ibuf	*buf;
39
40	if ((buf = calloc(1, sizeof(struct ibuf))) == NULL)
41		return (NULL);
42	if ((buf->buf = malloc(len)) == NULL) {
43		free(buf);
44		return (NULL);
45	}
46	buf->size = buf->max = len;
47	buf->fd = -1;
48
49	return (buf);
50}
51
52struct ibuf *
53ibuf_dynamic(size_t len, size_t max)
54{
55	struct ibuf	*buf;
56
57	if (max < len)
58		return (NULL);
59
60	if ((buf = ibuf_open(len)) == NULL)
61		return (NULL);
62
63	if (max > 0)
64		buf->max = max;
65
66	return (buf);
67}
68
69int
70ibuf_realloc(struct ibuf *buf, size_t len)
71{
72	u_char	*b;
73
74	/* on static buffers max is eq size and so the following fails */
75	if (buf->wpos + len > buf->max) {
76		errno = ENOMEM;
77		return (-1);
78	}
79
80	b = realloc(buf->buf, buf->wpos + len);
81	if (b == NULL)
82		return (-1);
83	buf->buf = b;
84	buf->size = buf->wpos + len;
85
86	return (0);
87}
88
89int
90ibuf_add(struct ibuf *buf, const void *data, size_t len)
91{
92	if (buf->wpos + len > buf->size)
93		if (ibuf_realloc(buf, len) == -1)
94			return (-1);
95
96	memcpy(buf->buf + buf->wpos, data, len);
97	buf->wpos += len;
98	return (0);
99}
100
101void *
102ibuf_reserve(struct ibuf *buf, size_t len)
103{
104	void	*b;
105
106	if (buf->wpos + len > buf->size)
107		if (ibuf_realloc(buf, len) == -1)
108			return (NULL);
109
110	b = buf->buf + buf->wpos;
111	buf->wpos += len;
112	return (b);
113}
114
115void *
116ibuf_seek(struct ibuf *buf, size_t pos, size_t len)
117{
118	/* only allowed to seek in already written parts */
119	if (pos + len > buf->wpos)
120		return (NULL);
121
122	return (buf->buf + pos);
123}
124
125size_t
126ibuf_size(struct ibuf *buf)
127{
128	return (buf->wpos);
129}
130
131size_t
132ibuf_left(struct ibuf *buf)
133{
134	return (buf->max - buf->wpos);
135}
136
137void
138ibuf_close(struct msgbuf *msgbuf, struct ibuf *buf)
139{
140	ibuf_enqueue(msgbuf, buf);
141}
142
143int
144ibuf_write(struct msgbuf *msgbuf)
145{
146	struct iovec	 iov[IOV_MAX];
147	struct ibuf	*buf;
148	unsigned int	 i = 0;
149	ssize_t	n;
150
151	bzero(&iov, sizeof(iov));
152	TAILQ_FOREACH(buf, &msgbuf->bufs, entry) {
153		if (i >= IOV_MAX)
154			break;
155		iov[i].iov_base = buf->buf + buf->rpos;
156		iov[i].iov_len = buf->wpos - buf->rpos;
157		i++;
158	}
159
160	if ((n = writev(msgbuf->fd, iov, i)) == -1) {
161		if (errno == EAGAIN || errno == ENOBUFS ||
162		    errno == EINTR)	/* try later */
163			return (0);
164		else
165			return (-1);
166	}
167
168	if (n == 0) {			/* connection closed */
169		errno = 0;
170		return (-2);
171	}
172
173	msgbuf_drain(msgbuf, n);
174
175	return (0);
176}
177
178void
179ibuf_free(struct ibuf *buf)
180{
181	free(buf->buf);
182	free(buf);
183}
184
185void
186msgbuf_init(struct msgbuf *msgbuf)
187{
188	msgbuf->queued = 0;
189	msgbuf->fd = -1;
190	TAILQ_INIT(&msgbuf->bufs);
191}
192
193void
194msgbuf_drain(struct msgbuf *msgbuf, size_t n)
195{
196	struct ibuf	*buf, *next;
197
198	for (buf = TAILQ_FIRST(&msgbuf->bufs); buf != NULL && n > 0;
199	    buf = next) {
200		next = TAILQ_NEXT(buf, entry);
201		if (buf->rpos + n >= buf->wpos) {
202			n -= buf->wpos - buf->rpos;
203			ibuf_dequeue(msgbuf, buf);
204		} else {
205			buf->rpos += n;
206			n = 0;
207		}
208	}
209}
210
211void
212msgbuf_clear(struct msgbuf *msgbuf)
213{
214	struct ibuf	*buf;
215
216	while ((buf = TAILQ_FIRST(&msgbuf->bufs)) != NULL)
217		ibuf_dequeue(msgbuf, buf);
218}
219
220int
221msgbuf_write(struct msgbuf *msgbuf)
222{
223	struct iovec	 iov[IOV_MAX];
224	struct ibuf	*buf;
225	unsigned int	 i = 0;
226	ssize_t		 n;
227	struct msghdr	 msg;
228	struct cmsghdr	*cmsg;
229	union {
230		struct cmsghdr	hdr;
231		char		buf[CMSG_SPACE(sizeof(int))];
232	} cmsgbuf;
233
234	bzero(&iov, sizeof(iov));
235	bzero(&msg, sizeof(msg));
236	TAILQ_FOREACH(buf, &msgbuf->bufs, entry) {
237		if (i >= IOV_MAX)
238			break;
239		iov[i].iov_base = buf->buf + buf->rpos;
240		iov[i].iov_len = buf->wpos - buf->rpos;
241		i++;
242		if (buf->fd != -1)
243			break;
244	}
245
246	msg.msg_iov = iov;
247	msg.msg_iovlen = i;
248
249	if (buf != NULL && buf->fd != -1) {
250		msg.msg_control = (caddr_t)&cmsgbuf.buf;
251		msg.msg_controllen = CMSG_SPACE(sizeof(int));
252		cmsg = CMSG_FIRSTHDR(&msg);
253		cmsg->cmsg_len = CMSG_LEN(sizeof(int));
254		cmsg->cmsg_level = SOL_SOCKET;
255		cmsg->cmsg_type = SCM_RIGHTS;
256		*(int *)CMSG_DATA(cmsg) = buf->fd;
257	}
258
259	if ((n = sendmsg(msgbuf->fd, &msg, 0)) == -1) {
260		if (errno == EAGAIN || errno == ENOBUFS ||
261		    errno == EINTR)	/* try later */
262			return (0);
263		else
264			return (-1);
265	}
266
267	if (n == 0) {			/* connection closed */
268		errno = 0;
269		return (-2);
270	}
271
272	/*
273	 * assumption: fd got sent if sendmsg sent anything
274	 * this works because fds are passed one at a time
275	 */
276	if (buf != NULL && buf->fd != -1) {
277		close(buf->fd);
278		buf->fd = -1;
279	}
280
281	msgbuf_drain(msgbuf, n);
282
283	return (0);
284}
285
286void
287ibuf_enqueue(struct msgbuf *msgbuf, struct ibuf *buf)
288{
289	TAILQ_INSERT_TAIL(&msgbuf->bufs, buf, entry);
290	msgbuf->queued++;
291}
292
293void
294ibuf_dequeue(struct msgbuf *msgbuf, struct ibuf *buf)
295{
296	TAILQ_REMOVE(&msgbuf->bufs, buf, entry);
297
298	if (buf->fd != -1)
299		close(buf->fd);
300
301	msgbuf->queued--;
302	ibuf_free(buf);
303}
304