1 /* $OpenBSD: imsg-buffer.c,v 1.7 2015/07/12 18:40:49 nicm 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 * $FreeBSD: head/lib/libopenbsd/imsg-buffer.c 290375 2015-11-04 23:52:19Z rodrigc $
19 */
20
21 #include <sys/types.h>
22 #include <sys/queue.h>
23 #include <sys/socket.h>
24 #include <sys/uio.h>
25
26 #include <limits.h>
27 #include <errno.h>
28 #include <stdlib.h>
29 #include <string.h>
30 #include <unistd.h>
31
32 #include "imsg.h"
33
34 int ibuf_realloc(struct ibuf *, size_t);
35 void ibuf_enqueue(struct msgbuf *, struct ibuf *);
36 void ibuf_dequeue(struct msgbuf *, struct ibuf *);
37
38 struct ibuf *
ibuf_open(size_t len)39 ibuf_open(size_t len)
40 {
41 struct ibuf *buf;
42
43 if ((buf = calloc(1, sizeof(struct ibuf))) == NULL)
44 return (NULL);
45 if ((buf->buf = malloc(len)) == NULL) {
46 free(buf);
47 return (NULL);
48 }
49 buf->size = buf->max = len;
50 buf->fd = -1;
51
52 return (buf);
53 }
54
55 struct ibuf *
ibuf_dynamic(size_t len,size_t max)56 ibuf_dynamic(size_t len, size_t max)
57 {
58 struct ibuf *buf;
59
60 if (max < len)
61 return (NULL);
62
63 if ((buf = ibuf_open(len)) == NULL)
64 return (NULL);
65
66 if (max > 0)
67 buf->max = max;
68
69 return (buf);
70 }
71
72 int
ibuf_realloc(struct ibuf * buf,size_t len)73 ibuf_realloc(struct ibuf *buf, size_t len)
74 {
75 u_char *b;
76
77 /* on static buffers max is eq size and so the following fails */
78 if (buf->wpos + len > buf->max) {
79 errno = ERANGE;
80 return (-1);
81 }
82
83 b = realloc(buf->buf, buf->wpos + len);
84 if (b == NULL)
85 return (-1);
86 buf->buf = b;
87 buf->size = buf->wpos + len;
88
89 return (0);
90 }
91
92 int
ibuf_add(struct ibuf * buf,const void * data,size_t len)93 ibuf_add(struct ibuf *buf, const void *data, size_t len)
94 {
95 if (buf->wpos + len > buf->size)
96 if (ibuf_realloc(buf, len) == -1)
97 return (-1);
98
99 memcpy(buf->buf + buf->wpos, data, len);
100 buf->wpos += len;
101 return (0);
102 }
103
104 void *
ibuf_reserve(struct ibuf * buf,size_t len)105 ibuf_reserve(struct ibuf *buf, size_t len)
106 {
107 void *b;
108
109 if (buf->wpos + len > buf->size)
110 if (ibuf_realloc(buf, len) == -1)
111 return (NULL);
112
113 b = buf->buf + buf->wpos;
114 buf->wpos += len;
115 return (b);
116 }
117
118 void *
ibuf_seek(struct ibuf * buf,size_t pos,size_t len)119 ibuf_seek(struct ibuf *buf, size_t pos, size_t len)
120 {
121 /* only allowed to seek in already written parts */
122 if (pos + len > buf->wpos)
123 return (NULL);
124
125 return (buf->buf + pos);
126 }
127
128 size_t
ibuf_size(struct ibuf * buf)129 ibuf_size(struct ibuf *buf)
130 {
131 return (buf->wpos);
132 }
133
134 size_t
ibuf_left(struct ibuf * buf)135 ibuf_left(struct ibuf *buf)
136 {
137 return (buf->max - buf->wpos);
138 }
139
140 void
ibuf_close(struct msgbuf * msgbuf,struct ibuf * buf)141 ibuf_close(struct msgbuf *msgbuf, struct ibuf *buf)
142 {
143 ibuf_enqueue(msgbuf, buf);
144 }
145
146 int
ibuf_write(struct msgbuf * msgbuf)147 ibuf_write(struct msgbuf *msgbuf)
148 {
149 struct iovec iov[IOV_MAX];
150 struct ibuf *buf;
151 unsigned int i = 0;
152 ssize_t n;
153
154 memset(&iov, 0, sizeof(iov));
155 TAILQ_FOREACH(buf, &msgbuf->bufs, entry) {
156 if (i >= IOV_MAX)
157 break;
158 iov[i].iov_base = buf->buf + buf->rpos;
159 iov[i].iov_len = buf->wpos - buf->rpos;
160 i++;
161 }
162
163 again:
164 if ((n = writev(msgbuf->fd, iov, i)) == -1) {
165 if (errno == EINTR)
166 goto again;
167 if (errno == ENOBUFS)
168 errno = EAGAIN;
169 return (-1);
170 }
171
172 if (n == 0) { /* connection closed */
173 errno = 0;
174 return (0);
175 }
176
177 msgbuf_drain(msgbuf, n);
178
179 return (1);
180 }
181
182 void
ibuf_free(struct ibuf * buf)183 ibuf_free(struct ibuf *buf)
184 {
185 free(buf->buf);
186 free(buf);
187 }
188
189 void
msgbuf_init(struct msgbuf * msgbuf)190 msgbuf_init(struct msgbuf *msgbuf)
191 {
192 msgbuf->queued = 0;
193 msgbuf->fd = -1;
194 TAILQ_INIT(&msgbuf->bufs);
195 }
196
197 void
msgbuf_drain(struct msgbuf * msgbuf,size_t n)198 msgbuf_drain(struct msgbuf *msgbuf, size_t n)
199 {
200 struct ibuf *buf, *next;
201
202 for (buf = TAILQ_FIRST(&msgbuf->bufs); buf != NULL && n > 0;
203 buf = next) {
204 next = TAILQ_NEXT(buf, entry);
205 if (buf->rpos + n >= buf->wpos) {
206 n -= buf->wpos - buf->rpos;
207 ibuf_dequeue(msgbuf, buf);
208 } else {
209 buf->rpos += n;
210 n = 0;
211 }
212 }
213 }
214
215 void
msgbuf_clear(struct msgbuf * msgbuf)216 msgbuf_clear(struct msgbuf *msgbuf)
217 {
218 struct ibuf *buf;
219
220 while ((buf = TAILQ_FIRST(&msgbuf->bufs)) != NULL)
221 ibuf_dequeue(msgbuf, buf);
222 }
223
224 int
msgbuf_write(struct msgbuf * msgbuf)225 msgbuf_write(struct msgbuf *msgbuf)
226 {
227 struct iovec iov[IOV_MAX];
228 struct ibuf *buf;
229 unsigned int i = 0;
230 ssize_t n;
231 struct msghdr msg;
232 struct cmsghdr *cmsg;
233 union {
234 struct cmsghdr hdr;
235 char buf[CMSG_SPACE(sizeof(int))];
236 } cmsgbuf;
237
238 memset(&iov, 0, sizeof(iov));
239 memset(&msg, 0, sizeof(msg));
240 memset(&cmsgbuf, 0, sizeof(cmsgbuf));
241 TAILQ_FOREACH(buf, &msgbuf->bufs, entry) {
242 if (i >= IOV_MAX)
243 break;
244 iov[i].iov_base = buf->buf + buf->rpos;
245 iov[i].iov_len = buf->wpos - buf->rpos;
246 i++;
247 if (buf->fd != -1)
248 break;
249 }
250
251 msg.msg_iov = iov;
252 msg.msg_iovlen = i;
253
254 if (buf != NULL && buf->fd != -1) {
255 msg.msg_control = (caddr_t)&cmsgbuf.buf;
256 msg.msg_controllen = sizeof(cmsgbuf.buf);
257 cmsg = CMSG_FIRSTHDR(&msg);
258 cmsg->cmsg_len = CMSG_LEN(sizeof(int));
259 cmsg->cmsg_level = SOL_SOCKET;
260 cmsg->cmsg_type = SCM_RIGHTS;
261 *(int *)CMSG_DATA(cmsg) = buf->fd;
262 }
263
264 again:
265 if ((n = sendmsg(msgbuf->fd, &msg, 0)) == -1) {
266 if (errno == EINTR)
267 goto again;
268 if (errno == ENOBUFS)
269 errno = EAGAIN;
270 return (-1);
271 }
272
273 if (n == 0) { /* connection closed */
274 errno = 0;
275 return (0);
276 }
277
278 /*
279 * assumption: fd got sent if sendmsg sent anything
280 * this works because fds are passed one at a time
281 */
282 if (buf != NULL && buf->fd != -1) {
283 close(buf->fd);
284 buf->fd = -1;
285 }
286
287 msgbuf_drain(msgbuf, n);
288
289 return (1);
290 }
291
292 void
ibuf_enqueue(struct msgbuf * msgbuf,struct ibuf * buf)293 ibuf_enqueue(struct msgbuf *msgbuf, struct ibuf *buf)
294 {
295 TAILQ_INSERT_TAIL(&msgbuf->bufs, buf, entry);
296 msgbuf->queued++;
297 }
298
299 void
ibuf_dequeue(struct msgbuf * msgbuf,struct ibuf * buf)300 ibuf_dequeue(struct msgbuf *msgbuf, struct ibuf *buf)
301 {
302 TAILQ_REMOVE(&msgbuf->bufs, buf, entry);
303
304 if (buf->fd != -1)
305 close(buf->fd);
306
307 msgbuf->queued--;
308 ibuf_free(buf);
309 }
310