1 b0003f58 2021-03-08 op /*	$OpenBSD: imsg-buffer.c,v 1.12 2019/01/20 02:50:03 bcook Exp $	*/
  2 b0003f58 2021-03-08 op 
  3 b0003f58 2021-03-08 op /*
  4 b0003f58 2021-03-08 op  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
  5 b0003f58 2021-03-08 op  *
  6 b0003f58 2021-03-08 op  * Permission to use, copy, modify, and distribute this software for any
  7 b0003f58 2021-03-08 op  * purpose with or without fee is hereby granted, provided that the above
  8 b0003f58 2021-03-08 op  * copyright notice and this permission notice appear in all copies.
  9 b0003f58 2021-03-08 op  *
 10 b0003f58 2021-03-08 op  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 11 b0003f58 2021-03-08 op  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 12 b0003f58 2021-03-08 op  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 13 b0003f58 2021-03-08 op  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 14 b0003f58 2021-03-08 op  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 15 b0003f58 2021-03-08 op  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 16 b0003f58 2021-03-08 op  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 17 b0003f58 2021-03-08 op  */
 18 b0003f58 2021-03-08 op 
 19 b0003f58 2021-03-08 op #include <sys/types.h>
 20 b0003f58 2021-03-08 op #include <sys/socket.h>
 21 b0003f58 2021-03-08 op #include <sys/uio.h>
 22 b0003f58 2021-03-08 op 
 23 b0003f58 2021-03-08 op #include <limits.h>
 24 b0003f58 2021-03-08 op #include <errno.h>
 25 b0003f58 2021-03-08 op #include <stdlib.h>
 26 b0003f58 2021-03-08 op #include <string.h>
 27 b0003f58 2021-03-08 op #include <unistd.h>
 28 b0003f58 2021-03-08 op 
 29 b0003f58 2021-03-08 op #include "imsg.h"
 30 b0003f58 2021-03-08 op 
 31 b0003f58 2021-03-08 op static int	ibuf_realloc(struct ibuf *, size_t);
 32 b0003f58 2021-03-08 op static void	ibuf_enqueue(struct msgbuf *, struct ibuf *);
 33 b0003f58 2021-03-08 op static void	ibuf_dequeue(struct msgbuf *, struct ibuf *);
 34 b0003f58 2021-03-08 op 
 35 b0003f58 2021-03-08 op struct ibuf *
 36 b0003f58 2021-03-08 op ibuf_open(size_t len)
 37 b0003f58 2021-03-08 op {
 38 b0003f58 2021-03-08 op 	struct ibuf	*buf;
 39 b0003f58 2021-03-08 op 
 40 b0003f58 2021-03-08 op 	if ((buf = calloc(1, sizeof(struct ibuf))) == NULL)
 41 b0003f58 2021-03-08 op 		return (NULL);
 42 b0003f58 2021-03-08 op 	if ((buf->buf = malloc(len)) == NULL) {
 43 b0003f58 2021-03-08 op 		free(buf);
 44 b0003f58 2021-03-08 op 		return (NULL);
 45 b0003f58 2021-03-08 op 	}
 46 b0003f58 2021-03-08 op 	buf->size = buf->max = len;
 47 b0003f58 2021-03-08 op 	buf->fd = -1;
 48 b0003f58 2021-03-08 op 
 49 b0003f58 2021-03-08 op 	return (buf);
 50 b0003f58 2021-03-08 op }
 51 b0003f58 2021-03-08 op 
 52 b0003f58 2021-03-08 op struct ibuf *
 53 b0003f58 2021-03-08 op ibuf_dynamic(size_t len, size_t max)
 54 b0003f58 2021-03-08 op {
 55 b0003f58 2021-03-08 op 	struct ibuf	*buf;
 56 b0003f58 2021-03-08 op 
 57 b0003f58 2021-03-08 op 	if (max < len)
 58 b0003f58 2021-03-08 op 		return (NULL);
 59 b0003f58 2021-03-08 op 
 60 b0003f58 2021-03-08 op 	if ((buf = ibuf_open(len)) == NULL)
 61 b0003f58 2021-03-08 op 		return (NULL);
 62 b0003f58 2021-03-08 op 
 63 b0003f58 2021-03-08 op 	if (max > 0)
 64 b0003f58 2021-03-08 op 		buf->max = max;
 65 b0003f58 2021-03-08 op 
 66 b0003f58 2021-03-08 op 	return (buf);
 67 b0003f58 2021-03-08 op }
 68 b0003f58 2021-03-08 op 
 69 b0003f58 2021-03-08 op static int
 70 b0003f58 2021-03-08 op ibuf_realloc(struct ibuf *buf, size_t len)
 71 b0003f58 2021-03-08 op {
 72 b0003f58 2021-03-08 op 	unsigned char	*b;
 73 b0003f58 2021-03-08 op 
 74 b0003f58 2021-03-08 op 	/* on static buffers max is eq size and so the following fails */
 75 b0003f58 2021-03-08 op 	if (buf->wpos + len > buf->max) {
 76 b0003f58 2021-03-08 op 		errno = ERANGE;
 77 b0003f58 2021-03-08 op 		return (-1);
 78 b0003f58 2021-03-08 op 	}
 79 b0003f58 2021-03-08 op 
 80 b0003f58 2021-03-08 op 	b = recallocarray(buf->buf, buf->size, buf->wpos + len, 1);
 81 b0003f58 2021-03-08 op 	if (b == NULL)
 82 b0003f58 2021-03-08 op 		return (-1);
 83 b0003f58 2021-03-08 op 	buf->buf = b;
 84 b0003f58 2021-03-08 op 	buf->size = buf->wpos + len;
 85 b0003f58 2021-03-08 op 
 86 b0003f58 2021-03-08 op 	return (0);
 87 b0003f58 2021-03-08 op }
 88 b0003f58 2021-03-08 op 
 89 b0003f58 2021-03-08 op int
 90 b0003f58 2021-03-08 op ibuf_add(struct ibuf *buf, const void *data, size_t len)
 91 b0003f58 2021-03-08 op {
 92 b0003f58 2021-03-08 op 	if (buf->wpos + len > buf->size)
 93 b0003f58 2021-03-08 op 		if (ibuf_realloc(buf, len) == -1)
 94 b0003f58 2021-03-08 op 			return (-1);
 95 b0003f58 2021-03-08 op 
 96 b0003f58 2021-03-08 op 	memcpy(buf->buf + buf->wpos, data, len);
 97 b0003f58 2021-03-08 op 	buf->wpos += len;
 98 b0003f58 2021-03-08 op 	return (0);
 99 b0003f58 2021-03-08 op }
100 b0003f58 2021-03-08 op 
101 b0003f58 2021-03-08 op void *
102 b0003f58 2021-03-08 op ibuf_reserve(struct ibuf *buf, size_t len)
103 b0003f58 2021-03-08 op {
104 b0003f58 2021-03-08 op 	void	*b;
105 b0003f58 2021-03-08 op 
106 b0003f58 2021-03-08 op 	if (buf->wpos + len > buf->size)
107 b0003f58 2021-03-08 op 		if (ibuf_realloc(buf, len) == -1)
108 b0003f58 2021-03-08 op 			return (NULL);
109 b0003f58 2021-03-08 op 
110 b0003f58 2021-03-08 op 	b = buf->buf + buf->wpos;
111 b0003f58 2021-03-08 op 	buf->wpos += len;
112 b0003f58 2021-03-08 op 	return (b);
113 b0003f58 2021-03-08 op }
114 b0003f58 2021-03-08 op 
115 b0003f58 2021-03-08 op void *
116 b0003f58 2021-03-08 op ibuf_seek(struct ibuf *buf, size_t pos, size_t len)
117 b0003f58 2021-03-08 op {
118 b0003f58 2021-03-08 op 	/* only allowed to seek in already written parts */
119 b0003f58 2021-03-08 op 	if (pos + len > buf->wpos)
120 b0003f58 2021-03-08 op 		return (NULL);
121 b0003f58 2021-03-08 op 
122 b0003f58 2021-03-08 op 	return (buf->buf + pos);
123 b0003f58 2021-03-08 op }
124 b0003f58 2021-03-08 op 
125 b0003f58 2021-03-08 op size_t
126 b0003f58 2021-03-08 op ibuf_size(struct ibuf *buf)
127 b0003f58 2021-03-08 op {
128 b0003f58 2021-03-08 op 	return (buf->wpos);
129 b0003f58 2021-03-08 op }
130 b0003f58 2021-03-08 op 
131 b0003f58 2021-03-08 op size_t
132 b0003f58 2021-03-08 op ibuf_left(struct ibuf *buf)
133 b0003f58 2021-03-08 op {
134 b0003f58 2021-03-08 op 	return (buf->max - buf->wpos);
135 b0003f58 2021-03-08 op }
136 b0003f58 2021-03-08 op 
137 b0003f58 2021-03-08 op void
138 b0003f58 2021-03-08 op ibuf_close(struct msgbuf *msgbuf, struct ibuf *buf)
139 b0003f58 2021-03-08 op {
140 b0003f58 2021-03-08 op 	ibuf_enqueue(msgbuf, buf);
141 b0003f58 2021-03-08 op }
142 b0003f58 2021-03-08 op 
143 b0003f58 2021-03-08 op int
144 b0003f58 2021-03-08 op ibuf_write(struct msgbuf *msgbuf)
145 b0003f58 2021-03-08 op {
146 b0003f58 2021-03-08 op 	struct iovec	 iov[IOV_MAX];
147 b0003f58 2021-03-08 op 	struct ibuf	*buf;
148 b0003f58 2021-03-08 op 	unsigned int	 i = 0;
149 b0003f58 2021-03-08 op 	ssize_t	n;
150 b0003f58 2021-03-08 op 
151 b0003f58 2021-03-08 op 	memset(&iov, 0, sizeof(iov));
152 b0003f58 2021-03-08 op 	TAILQ_FOREACH(buf, &msgbuf->bufs, entry) {
153 b0003f58 2021-03-08 op 		if (i >= IOV_MAX)
154 b0003f58 2021-03-08 op 			break;
155 b0003f58 2021-03-08 op 		iov[i].iov_base = buf->buf + buf->rpos;
156 b0003f58 2021-03-08 op 		iov[i].iov_len = buf->wpos - buf->rpos;
157 b0003f58 2021-03-08 op 		i++;
158 b0003f58 2021-03-08 op 	}
159 b0003f58 2021-03-08 op 
160 b0003f58 2021-03-08 op again:
161 b0003f58 2021-03-08 op 	if ((n = writev(msgbuf->fd, iov, i)) == -1) {
162 b0003f58 2021-03-08 op 		if (errno == EINTR)
163 b0003f58 2021-03-08 op 			goto again;
164 b0003f58 2021-03-08 op 		if (errno == ENOBUFS)
165 b0003f58 2021-03-08 op 			errno = EAGAIN;
166 b0003f58 2021-03-08 op 		return (-1);
167 b0003f58 2021-03-08 op 	}
168 b0003f58 2021-03-08 op 
169 b0003f58 2021-03-08 op 	if (n == 0) {			/* connection closed */
170 b0003f58 2021-03-08 op 		errno = 0;
171 b0003f58 2021-03-08 op 		return (0);
172 b0003f58 2021-03-08 op 	}
173 b0003f58 2021-03-08 op 
174 b0003f58 2021-03-08 op 	msgbuf_drain(msgbuf, n);
175 b0003f58 2021-03-08 op 
176 b0003f58 2021-03-08 op 	return (1);
177 b0003f58 2021-03-08 op }
178 b0003f58 2021-03-08 op 
179 b0003f58 2021-03-08 op void
180 b0003f58 2021-03-08 op ibuf_free(struct ibuf *buf)
181 b0003f58 2021-03-08 op {
182 b0003f58 2021-03-08 op 	if (buf == NULL)
183 b0003f58 2021-03-08 op 		return;
184 b0003f58 2021-03-08 op 	freezero(buf->buf, buf->size);
185 b0003f58 2021-03-08 op 	free(buf);
186 b0003f58 2021-03-08 op }
187 b0003f58 2021-03-08 op 
188 b0003f58 2021-03-08 op void
189 b0003f58 2021-03-08 op msgbuf_init(struct msgbuf *msgbuf)
190 b0003f58 2021-03-08 op {
191 b0003f58 2021-03-08 op 	msgbuf->queued = 0;
192 b0003f58 2021-03-08 op 	msgbuf->fd = -1;
193 b0003f58 2021-03-08 op 	TAILQ_INIT(&msgbuf->bufs);
194 b0003f58 2021-03-08 op }
195 b0003f58 2021-03-08 op 
196 b0003f58 2021-03-08 op void
197 b0003f58 2021-03-08 op msgbuf_drain(struct msgbuf *msgbuf, size_t n)
198 b0003f58 2021-03-08 op {
199 b0003f58 2021-03-08 op 	struct ibuf	*buf, *next;
200 b0003f58 2021-03-08 op 
201 b0003f58 2021-03-08 op 	for (buf = TAILQ_FIRST(&msgbuf->bufs); buf != NULL && n > 0;
202 b0003f58 2021-03-08 op 	    buf = next) {
203 b0003f58 2021-03-08 op 		next = TAILQ_NEXT(buf, entry);
204 b0003f58 2021-03-08 op 		if (buf->rpos + n >= buf->wpos) {
205 b0003f58 2021-03-08 op 			n -= buf->wpos - buf->rpos;
206 b0003f58 2021-03-08 op 			ibuf_dequeue(msgbuf, buf);
207 b0003f58 2021-03-08 op 		} else {
208 b0003f58 2021-03-08 op 			buf->rpos += n;
209 b0003f58 2021-03-08 op 			n = 0;
210 b0003f58 2021-03-08 op 		}
211 b0003f58 2021-03-08 op 	}
212 b0003f58 2021-03-08 op }
213 b0003f58 2021-03-08 op 
214 b0003f58 2021-03-08 op void
215 b0003f58 2021-03-08 op msgbuf_clear(struct msgbuf *msgbuf)
216 b0003f58 2021-03-08 op {
217 b0003f58 2021-03-08 op 	struct ibuf	*buf;
218 b0003f58 2021-03-08 op 
219 b0003f58 2021-03-08 op 	while ((buf = TAILQ_FIRST(&msgbuf->bufs)) != NULL)
220 b0003f58 2021-03-08 op 		ibuf_dequeue(msgbuf, buf);
221 b0003f58 2021-03-08 op }
222 b0003f58 2021-03-08 op 
223 b0003f58 2021-03-08 op int
224 b0003f58 2021-03-08 op msgbuf_write(struct msgbuf *msgbuf)
225 b0003f58 2021-03-08 op {
226 b0003f58 2021-03-08 op 	struct iovec	 iov[IOV_MAX];
227 b0003f58 2021-03-08 op 	struct ibuf	*buf;
228 b0003f58 2021-03-08 op 	unsigned int	 i = 0;
229 b0003f58 2021-03-08 op 	ssize_t		 n;
230 b0003f58 2021-03-08 op 	struct msghdr	 msg;
231 b0003f58 2021-03-08 op 	struct cmsghdr	*cmsg;
232 b0003f58 2021-03-08 op 	union {
233 b0003f58 2021-03-08 op 		struct cmsghdr	hdr;
234 b0003f58 2021-03-08 op 		char		buf[CMSG_SPACE(sizeof(int))];
235 b0003f58 2021-03-08 op 	} cmsgbuf;
236 b0003f58 2021-03-08 op 
237 b0003f58 2021-03-08 op 	memset(&iov, 0, sizeof(iov));
238 b0003f58 2021-03-08 op 	memset(&msg, 0, sizeof(msg));
239 b0003f58 2021-03-08 op 	memset(&cmsgbuf, 0, sizeof(cmsgbuf));
240 b0003f58 2021-03-08 op 	TAILQ_FOREACH(buf, &msgbuf->bufs, entry) {
241 b0003f58 2021-03-08 op 		if (i >= IOV_MAX)
242 b0003f58 2021-03-08 op 			break;
243 b0003f58 2021-03-08 op 		iov[i].iov_base = buf->buf + buf->rpos;
244 b0003f58 2021-03-08 op 		iov[i].iov_len = buf->wpos - buf->rpos;
245 b0003f58 2021-03-08 op 		i++;
246 b0003f58 2021-03-08 op 		if (buf->fd != -1)
247 b0003f58 2021-03-08 op 			break;
248 b0003f58 2021-03-08 op 	}
249 b0003f58 2021-03-08 op 
250 b0003f58 2021-03-08 op 	msg.msg_iov = iov;
251 b0003f58 2021-03-08 op 	msg.msg_iovlen = i;
252 b0003f58 2021-03-08 op 
253 b0003f58 2021-03-08 op 	if (buf != NULL && buf->fd != -1) {
254 b0003f58 2021-03-08 op 		msg.msg_control = (caddr_t)&cmsgbuf.buf;
255 b0003f58 2021-03-08 op 		msg.msg_controllen = sizeof(cmsgbuf.buf);
256 b0003f58 2021-03-08 op 		cmsg = CMSG_FIRSTHDR(&msg);
257 b0003f58 2021-03-08 op 		cmsg->cmsg_len = CMSG_LEN(sizeof(int));
258 b0003f58 2021-03-08 op 		cmsg->cmsg_level = SOL_SOCKET;
259 b0003f58 2021-03-08 op 		cmsg->cmsg_type = SCM_RIGHTS;
260 b0003f58 2021-03-08 op 		*(int *)CMSG_DATA(cmsg) = buf->fd;
261 b0003f58 2021-03-08 op 	}
262 b0003f58 2021-03-08 op 
263 b0003f58 2021-03-08 op again:
264 b0003f58 2021-03-08 op 	if ((n = sendmsg(msgbuf->fd, &msg, 0)) == -1) {
265 b0003f58 2021-03-08 op 		if (errno == EINTR)
266 b0003f58 2021-03-08 op 			goto again;
267 b0003f58 2021-03-08 op 		if (errno == ENOBUFS)
268 b0003f58 2021-03-08 op 			errno = EAGAIN;
269 b0003f58 2021-03-08 op 		return (-1);
270 b0003f58 2021-03-08 op 	}
271 b0003f58 2021-03-08 op 
272 b0003f58 2021-03-08 op 	if (n == 0) {			/* connection closed */
273 b0003f58 2021-03-08 op 		errno = 0;
274 b0003f58 2021-03-08 op 		return (0);
275 b0003f58 2021-03-08 op 	}
276 b0003f58 2021-03-08 op 
277 b0003f58 2021-03-08 op 	/*
278 b0003f58 2021-03-08 op 	 * assumption: fd got sent if sendmsg sent anything
279 b0003f58 2021-03-08 op 	 * this works because fds are passed one at a time
280 b0003f58 2021-03-08 op 	 */
281 b0003f58 2021-03-08 op 	if (buf != NULL && buf->fd != -1) {
282 b0003f58 2021-03-08 op 		close(buf->fd);
283 b0003f58 2021-03-08 op 		buf->fd = -1;
284 b0003f58 2021-03-08 op 	}
285 b0003f58 2021-03-08 op 
286 b0003f58 2021-03-08 op 	msgbuf_drain(msgbuf, n);
287 b0003f58 2021-03-08 op 
288 b0003f58 2021-03-08 op 	return (1);
289 b0003f58 2021-03-08 op }
290 b0003f58 2021-03-08 op 
291 b0003f58 2021-03-08 op static void
292 b0003f58 2021-03-08 op ibuf_enqueue(struct msgbuf *msgbuf, struct ibuf *buf)
293 b0003f58 2021-03-08 op {
294 b0003f58 2021-03-08 op 	TAILQ_INSERT_TAIL(&msgbuf->bufs, buf, entry);
295 b0003f58 2021-03-08 op 	msgbuf->queued++;
296 b0003f58 2021-03-08 op }
297 b0003f58 2021-03-08 op 
298 b0003f58 2021-03-08 op static void
299 b0003f58 2021-03-08 op ibuf_dequeue(struct msgbuf *msgbuf, struct ibuf *buf)
300 b0003f58 2021-03-08 op {
301 b0003f58 2021-03-08 op 	TAILQ_REMOVE(&msgbuf->bufs, buf, entry);
302 b0003f58 2021-03-08 op 
303 b0003f58 2021-03-08 op 	if (buf->fd != -1)
304 b0003f58 2021-03-08 op 		close(buf->fd);
305 b0003f58 2021-03-08 op 
306 b0003f58 2021-03-08 op 	msgbuf->queued--;
307 b0003f58 2021-03-08 op 	ibuf_free(buf);
308 b0003f58 2021-03-08 op }