1 /* $OpenBSD: imsg-buffer.c,v 1.4 2014/06/30 00:25:17 deraadt 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 "config.h"
20 #include "compat/compat.h"
21
22 #include <sys/types.h>
23 #include <sys/queue.h>
24 #include <sys/socket.h>
25 #include <sys/uio.h>
26
27 #include <limits.h>
28 #include <errno.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <unistd.h>
32
33 #include "imsg.h"
34
35 int ibuf_realloc(struct ibuf *, size_t);
36 void ibuf_enqueue(struct msgbuf *, struct ibuf *);
37 void ibuf_dequeue(struct msgbuf *, struct ibuf *);
38
39 struct ibuf *
ibuf_open(size_t len)40 ibuf_open(size_t len)
41 {
42 struct ibuf *buf;
43
44 if ((buf = calloc(1, sizeof(struct ibuf))) == NULL)
45 return (NULL);
46 if ((buf->buf = malloc(len)) == NULL) {
47 free(buf);
48 return (NULL);
49 }
50 buf->size = buf->max = len;
51 buf->fd = -1;
52
53 return (buf);
54 }
55
56 struct ibuf *
ibuf_dynamic(size_t len,size_t max)57 ibuf_dynamic(size_t len, size_t max)
58 {
59 struct ibuf *buf;
60
61 if (max < len)
62 return (NULL);
63
64 if ((buf = ibuf_open(len)) == NULL)
65 return (NULL);
66
67 if (max > 0)
68 buf->max = max;
69
70 return (buf);
71 }
72
73 int
ibuf_realloc(struct ibuf * buf,size_t len)74 ibuf_realloc(struct ibuf *buf, size_t len)
75 {
76 u_char *b;
77
78 /* on static buffers max is eq size and so the following fails */
79 if (buf->wpos + len > buf->max) {
80 errno = ENOMEM;
81 return (-1);
82 }
83
84 b = realloc(buf->buf, buf->wpos + len);
85 if (b == NULL)
86 return (-1);
87 buf->buf = b;
88 buf->size = buf->wpos + len;
89
90 return (0);
91 }
92
93 int
ibuf_add(struct ibuf * buf,const void * data,size_t len)94 ibuf_add(struct ibuf *buf, const void *data, size_t len)
95 {
96 if (buf->wpos + len > buf->size)
97 if (ibuf_realloc(buf, len) == -1)
98 return (-1);
99
100 memcpy(buf->buf + buf->wpos, data, len);
101 buf->wpos += len;
102 return (0);
103 }
104
105 void *
ibuf_reserve(struct ibuf * buf,size_t len)106 ibuf_reserve(struct ibuf *buf, size_t len)
107 {
108 void *b;
109
110 if (buf->wpos + len > buf->size)
111 if (ibuf_realloc(buf, len) == -1)
112 return (NULL);
113
114 b = buf->buf + buf->wpos;
115 buf->wpos += len;
116 return (b);
117 }
118
119 void *
ibuf_seek(struct ibuf * buf,size_t pos,size_t len)120 ibuf_seek(struct ibuf *buf, size_t pos, size_t len)
121 {
122 /* only allowed to seek in already written parts */
123 if (pos + len > buf->wpos)
124 return (NULL);
125
126 return (buf->buf + pos);
127 }
128
129 size_t
ibuf_size(struct ibuf * buf)130 ibuf_size(struct ibuf *buf)
131 {
132 return (buf->wpos);
133 }
134
135 size_t
ibuf_left(struct ibuf * buf)136 ibuf_left(struct ibuf *buf)
137 {
138 return (buf->max - buf->wpos);
139 }
140
141 void
ibuf_close(struct msgbuf * msgbuf,struct ibuf * buf)142 ibuf_close(struct msgbuf *msgbuf, struct ibuf *buf)
143 {
144 ibuf_enqueue(msgbuf, buf);
145 }
146
147 int
ibuf_write(struct msgbuf * msgbuf)148 ibuf_write(struct msgbuf *msgbuf)
149 {
150 struct iovec iov[IOV_MAX];
151 struct ibuf *buf;
152 unsigned int i = 0;
153 ssize_t n;
154
155 bzero(&iov, sizeof(iov));
156 TAILQ_FOREACH(buf, &msgbuf->bufs, entry) {
157 if (i >= IOV_MAX)
158 break;
159 iov[i].iov_base = buf->buf + buf->rpos;
160 iov[i].iov_len = buf->wpos - buf->rpos;
161 i++;
162 }
163
164 again:
165 if ((n = writev(msgbuf->fd, iov, i)) == -1) {
166 if (errno == EINTR)
167 goto again;
168 if (errno == ENOBUFS)
169 errno = EAGAIN;
170 return (-1);
171 }
172
173 if (n == 0) { /* connection closed */
174 errno = 0;
175 return (0);
176 }
177
178 msgbuf_drain(msgbuf, n);
179
180 return (1);
181 }
182
183 void
ibuf_free(struct ibuf * buf)184 ibuf_free(struct ibuf *buf)
185 {
186 free(buf->buf);
187 free(buf);
188 }
189
190 void
msgbuf_init(struct msgbuf * msgbuf)191 msgbuf_init(struct msgbuf *msgbuf)
192 {
193 msgbuf->queued = 0;
194 msgbuf->fd = -1;
195 TAILQ_INIT(&msgbuf->bufs);
196 }
197
198 void
msgbuf_drain(struct msgbuf * msgbuf,size_t n)199 msgbuf_drain(struct msgbuf *msgbuf, size_t n)
200 {
201 struct ibuf *buf, *next;
202
203 for (buf = TAILQ_FIRST(&msgbuf->bufs); buf != NULL && n > 0;
204 buf = next) {
205 next = TAILQ_NEXT(buf, entry);
206 if (buf->rpos + n >= buf->wpos) {
207 n -= buf->wpos - buf->rpos;
208 ibuf_dequeue(msgbuf, buf);
209 } else {
210 buf->rpos += n;
211 n = 0;
212 }
213 }
214 }
215
216 void
msgbuf_clear(struct msgbuf * msgbuf)217 msgbuf_clear(struct msgbuf *msgbuf)
218 {
219 struct ibuf *buf;
220
221 while ((buf = TAILQ_FIRST(&msgbuf->bufs)) != NULL)
222 ibuf_dequeue(msgbuf, buf);
223 }
224
225 int
msgbuf_write(struct msgbuf * msgbuf)226 msgbuf_write(struct msgbuf *msgbuf)
227 {
228 struct iovec iov[IOV_MAX];
229 struct ibuf *buf;
230 unsigned int i = 0;
231 ssize_t n;
232 struct msghdr msg;
233 struct cmsghdr *cmsg;
234 union {
235 struct cmsghdr hdr;
236 char buf[CMSG_SPACE(sizeof(int))];
237 } cmsgbuf;
238
239 bzero(&iov, sizeof(iov));
240 bzero(&msg, sizeof(msg));
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 memcpy(CMSG_DATA(cmsg), &buf->fd, sizeof(int));
263 }
264
265 again:
266 if ((n = sendmsg(msgbuf->fd, &msg, 0)) == -1) {
267 if (errno == EINTR)
268 goto again;
269 if (errno == ENOBUFS)
270 errno = EAGAIN;
271 return (-1);
272 }
273
274 if (n == 0) { /* connection closed */
275 errno = 0;
276 return (0);
277 }
278
279 /*
280 * assumption: fd got sent if sendmsg sent anything
281 * this works because fds are passed one at a time
282 */
283 if (buf != NULL && buf->fd != -1) {
284 close(buf->fd);
285 buf->fd = -1;
286 }
287
288 msgbuf_drain(msgbuf, n);
289
290 return (1);
291 }
292
293 void
ibuf_enqueue(struct msgbuf * msgbuf,struct ibuf * buf)294 ibuf_enqueue(struct msgbuf *msgbuf, struct ibuf *buf)
295 {
296 TAILQ_INSERT_TAIL(&msgbuf->bufs, buf, entry);
297 msgbuf->queued++;
298 }
299
300 void
ibuf_dequeue(struct msgbuf * msgbuf,struct ibuf * buf)301 ibuf_dequeue(struct msgbuf *msgbuf, struct ibuf *buf)
302 {
303 TAILQ_REMOVE(&msgbuf->bufs, buf, entry);
304
305 if (buf->fd != -1)
306 close(buf->fd);
307
308 msgbuf->queued--;
309 ibuf_free(buf);
310 }
311