1 /* $OpenBSD: imsg-buffer.c,v 1.3 2013/11/13 20:40:24 benno Exp $ */
2
3 /*
4 * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19 #include "includes.h"
20
21 #include <sys/param.h>
22 #include <sys/queue.h>
23 #include <sys/socket.h>
24 #include <sys/uio.h>
25
26 #include <errno.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <unistd.h>
30
31 #include "imsg.h"
32
33 int ibuf_realloc(struct ibuf *, size_t);
34 void ibuf_enqueue(struct msgbuf *, struct ibuf *);
35 void ibuf_dequeue(struct msgbuf *, struct ibuf *);
36
37 struct ibuf *
ibuf_open(size_t len)38 ibuf_open(size_t len)
39 {
40 struct ibuf *buf;
41
42 if ((buf = calloc(1, sizeof(struct ibuf))) == NULL)
43 return (NULL);
44 if ((buf->buf = malloc(len)) == NULL) {
45 free(buf);
46 return (NULL);
47 }
48 buf->size = buf->max = len;
49 buf->fd = -1;
50
51 return (buf);
52 }
53
54 struct ibuf *
ibuf_dynamic(size_t len,size_t max)55 ibuf_dynamic(size_t len, size_t max)
56 {
57 struct ibuf *buf;
58
59 if (max < len)
60 return (NULL);
61
62 if ((buf = ibuf_open(len)) == NULL)
63 return (NULL);
64
65 if (max > 0)
66 buf->max = max;
67
68 return (buf);
69 }
70
71 int
ibuf_realloc(struct ibuf * buf,size_t len)72 ibuf_realloc(struct ibuf *buf, size_t len)
73 {
74 unsigned char *b;
75
76 /* on static buffers max is eq size and so the following fails */
77 if (buf->wpos + len > buf->max) {
78 errno = ENOMEM;
79 return (-1);
80 }
81
82 b = realloc(buf->buf, buf->wpos + len);
83 if (b == NULL)
84 return (-1);
85 buf->buf = b;
86 buf->size = buf->wpos + len;
87
88 return (0);
89 }
90
91 int
ibuf_add(struct ibuf * buf,const void * data,size_t len)92 ibuf_add(struct ibuf *buf, const void *data, size_t len)
93 {
94 if (buf->wpos + len > buf->size)
95 if (ibuf_realloc(buf, len) == -1)
96 return (-1);
97
98 memcpy(buf->buf + buf->wpos, data, len);
99 buf->wpos += len;
100 return (0);
101 }
102
103 void *
ibuf_reserve(struct ibuf * buf,size_t len)104 ibuf_reserve(struct ibuf *buf, size_t len)
105 {
106 void *b;
107
108 if (buf->wpos + len > buf->size)
109 if (ibuf_realloc(buf, len) == -1)
110 return (NULL);
111
112 b = buf->buf + buf->wpos;
113 buf->wpos += len;
114 return (b);
115 }
116
117 void *
ibuf_seek(struct ibuf * buf,size_t pos,size_t len)118 ibuf_seek(struct ibuf *buf, size_t pos, size_t len)
119 {
120 /* only allowed to seek in already written parts */
121 if (pos + len > buf->wpos)
122 return (NULL);
123
124 return (buf->buf + pos);
125 }
126
127 size_t
ibuf_size(struct ibuf * buf)128 ibuf_size(struct ibuf *buf)
129 {
130 return (buf->wpos);
131 }
132
133 size_t
ibuf_left(struct ibuf * buf)134 ibuf_left(struct ibuf *buf)
135 {
136 return (buf->max - buf->wpos);
137 }
138
139 void
ibuf_close(struct msgbuf * msgbuf,struct ibuf * buf)140 ibuf_close(struct msgbuf *msgbuf, struct ibuf *buf)
141 {
142 ibuf_enqueue(msgbuf, buf);
143 }
144
145 int
ibuf_write(struct msgbuf * msgbuf)146 ibuf_write(struct msgbuf *msgbuf)
147 {
148 struct iovec iov[IOV_MAX];
149 struct ibuf *buf;
150 unsigned int i = 0;
151 ssize_t n;
152
153 memset(&iov, 0, sizeof(iov));
154 TAILQ_FOREACH(buf, &msgbuf->bufs, entry) {
155 if (i >= IOV_MAX)
156 break;
157 iov[i].iov_base = buf->buf + buf->rpos;
158 iov[i].iov_len = buf->wpos - buf->rpos;
159 i++;
160 }
161
162 again:
163 if ((n = writev(msgbuf->fd, iov, i)) == -1) {
164 if (errno == EINTR)
165 goto again;
166 if (errno == ENOBUFS)
167 errno = EAGAIN;
168 return (-1);
169 }
170
171 if (n == 0) { /* connection closed */
172 errno = 0;
173 return (0);
174 }
175
176 msgbuf_drain(msgbuf, n);
177
178 return (1);
179 }
180
181 void
ibuf_free(struct ibuf * buf)182 ibuf_free(struct ibuf *buf)
183 {
184 free(buf->buf);
185 free(buf);
186 }
187
188 void
msgbuf_init(struct msgbuf * msgbuf)189 msgbuf_init(struct msgbuf *msgbuf)
190 {
191 msgbuf->queued = 0;
192 msgbuf->fd = -1;
193 TAILQ_INIT(&msgbuf->bufs);
194 }
195
196 void
msgbuf_drain(struct msgbuf * msgbuf,size_t n)197 msgbuf_drain(struct msgbuf *msgbuf, size_t n)
198 {
199 struct ibuf *buf, *next;
200
201 for (buf = TAILQ_FIRST(&msgbuf->bufs); buf != NULL && n > 0;
202 buf = next) {
203 next = TAILQ_NEXT(buf, entry);
204 if (buf->rpos + n >= buf->wpos) {
205 n -= buf->wpos - buf->rpos;
206 ibuf_dequeue(msgbuf, buf);
207 } else {
208 buf->rpos += n;
209 n = 0;
210 }
211 }
212 }
213
214 void
msgbuf_clear(struct msgbuf * msgbuf)215 msgbuf_clear(struct msgbuf *msgbuf)
216 {
217 struct ibuf *buf;
218
219 while ((buf = TAILQ_FIRST(&msgbuf->bufs)) != NULL)
220 ibuf_dequeue(msgbuf, buf);
221 }
222
223 int
msgbuf_write(struct msgbuf * msgbuf)224 msgbuf_write(struct msgbuf *msgbuf)
225 {
226 struct iovec iov[IOV_MAX];
227 struct ibuf *buf;
228 unsigned int i = 0;
229 ssize_t n;
230 struct msghdr msg;
231 struct cmsghdr *cmsg;
232 union {
233 struct cmsghdr hdr;
234 char buf[CMSG_SPACE(sizeof(int))];
235 } cmsgbuf;
236
237 memset(&iov, 0, sizeof(iov));
238 memset(&msg, 0, sizeof(msg));
239 TAILQ_FOREACH(buf, &msgbuf->bufs, entry) {
240 if (i >= IOV_MAX)
241 break;
242 iov[i].iov_base = buf->buf + buf->rpos;
243 iov[i].iov_len = buf->wpos - buf->rpos;
244 i++;
245 if (buf->fd != -1)
246 break;
247 }
248
249 msg.msg_iov = iov;
250 msg.msg_iovlen = i;
251
252 if (buf != NULL && buf->fd != -1) {
253 msg.msg_control = (caddr_t)&cmsgbuf.buf;
254 msg.msg_controllen = sizeof(cmsgbuf.buf);
255 cmsg = CMSG_FIRSTHDR(&msg);
256 cmsg->cmsg_len = CMSG_LEN(sizeof(int));
257 cmsg->cmsg_level = SOL_SOCKET;
258 cmsg->cmsg_type = SCM_RIGHTS;
259 *(int *)CMSG_DATA(cmsg) = buf->fd;
260 }
261
262 again:
263 if ((n = sendmsg(msgbuf->fd, &msg, 0)) == -1) {
264 if (errno == EINTR)
265 goto again;
266 if (errno == ENOBUFS)
267 errno = EAGAIN;
268 return (-1);
269 }
270
271 if (n == 0) { /* connection closed */
272 errno = 0;
273 return (0);
274 }
275
276 /*
277 * assumption: fd got sent if sendmsg sent anything
278 * this works because fds are passed one at a time
279 */
280 if (buf != NULL && buf->fd != -1) {
281 close(buf->fd);
282 buf->fd = -1;
283 }
284
285 msgbuf_drain(msgbuf, n);
286
287 return (1);
288 }
289
290 void
ibuf_enqueue(struct msgbuf * msgbuf,struct ibuf * buf)291 ibuf_enqueue(struct msgbuf *msgbuf, struct ibuf *buf)
292 {
293 TAILQ_INSERT_TAIL(&msgbuf->bufs, buf, entry);
294 msgbuf->queued++;
295 }
296
297 void
ibuf_dequeue(struct msgbuf * msgbuf,struct ibuf * buf)298 ibuf_dequeue(struct msgbuf *msgbuf, struct ibuf *buf)
299 {
300 TAILQ_REMOVE(&msgbuf->bufs, buf, entry);
301
302 if (buf->fd != -1)
303 close(buf->fd);
304
305 msgbuf->queued--;
306 ibuf_free(buf);
307 }
308