1/* $OpenBSD: imsg-buffer.c,v 1.11 2017/12/14 09:27:44 kettenis Exp $ */
2
3/*
4 * Copyright (c) 2003, 2004 Henning Brauer <[email protected]>
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 <sys/types.h>
20#include <sys/socket.h>
21#include <sys/uio.h>
22
23#include <limits.h>
24#include <errno.h>
25#include <stdlib.h>
26#include <string.h>
27#include <unistd.h>
28
29#include "compat.h"
30#include "imsg.h"
31
32static int ibuf_realloc(struct ibuf *, size_t);
33static void ibuf_enqueue(struct msgbuf *, struct ibuf *);
34static void ibuf_dequeue(struct msgbuf *, struct ibuf *);
35
36struct ibuf *
37ibuf_open(size_t len)
38{
39 struct ibuf *buf;
40
41 if ((buf = calloc(1, sizeof(struct ibuf))) == NULL)
42 return (NULL);
43 if ((buf->buf = malloc(len)) == NULL) {
44 free(buf);
45 return (NULL);
46 }
47 buf->size = buf->max = len;
48 buf->fd = -1;
49
50 return (buf);
51}
52
53struct ibuf *
54ibuf_dynamic(size_t len, size_t max)
55{
56 struct ibuf *buf;
57
58 if (max < len)
59 return (NULL);
60
61 if ((buf = ibuf_open(len)) == NULL)
62 return (NULL);
63
64 if (max > 0)
65 buf->max = max;
66
67 return (buf);
68}
69
70static int
71ibuf_realloc(struct ibuf *buf, size_t len)
72{
73 u_char *b;
74
75 /* on static buffers max is eq size and so the following fails */
76 if (buf->wpos + len > buf->max) {
77 errno = ERANGE;
78 return (-1);
79 }
80
81 b = recallocarray(buf->buf, buf->size, buf->wpos + len, 1);
82 if (b == NULL)
83 return (-1);
84 buf->buf = b;
85 buf->size = buf->wpos + len;
86
87 return (0);
88}
89
90int
91ibuf_add(struct ibuf *buf, const void *data, size_t len)
92{
93 if (buf->wpos + len > buf->size)
94 if (ibuf_realloc(buf, len) == -1)
95 return (-1);
96
97 memcpy(buf->buf + buf->wpos, data, len);
98 buf->wpos += len;
99 return (0);
100}
101
102void *
103ibuf_reserve(struct ibuf *buf, size_t len)
104{
105 void *b;
106
107 if (buf->wpos + len > buf->size)
108 if (ibuf_realloc(buf, len) == -1)
109 return (NULL);
110
111 b = buf->buf + buf->wpos;
112 buf->wpos += len;
113 return (b);
114}
115
116void *
117ibuf_seek(struct ibuf *buf, size_t pos, size_t len)
118{
119 /* only allowed to seek in already written parts */
120 if (pos + len > buf->wpos)
121 return (NULL);
122
123 return (buf->buf + pos);
124}
125
126size_t
127ibuf_size(struct ibuf *buf)
128{
129 return (buf->wpos);
130}
131
132size_t
133ibuf_left(struct ibuf *buf)
134{
135 return (buf->max - buf->wpos);
136}
137
138void
139ibuf_close(struct msgbuf *msgbuf, struct ibuf *buf)
140{
141 ibuf_enqueue(msgbuf, buf);
142}
143
144int
145ibuf_write(struct msgbuf *msgbuf)
146{
147 struct iovec iov[IOV_MAX];
148 struct ibuf *buf;
149 unsigned int i = 0;
150 ssize_t n;
151
152 memset(&iov, 0, sizeof(iov));
153 TAILQ_FOREACH(buf, &msgbuf->bufs, entry) {
154 if (i >= IOV_MAX)
155 break;
156 iov[i].iov_base = buf->buf + buf->rpos;
157 iov[i].iov_len = buf->wpos - buf->rpos;
158 i++;
159 }
160
161again:
162 if ((n = writev(msgbuf->fd, iov, i)) == -1) {
163 if (errno == EINTR)
164 goto again;
165 if (errno == ENOBUFS)
166 errno = EAGAIN;
167 return (-1);
168 }
169
170 if (n == 0) { /* connection closed */
171 errno = 0;
172 return (0);
173 }
174
175 msgbuf_drain(msgbuf, n);
176
177 return (1);
178}
179
180void
181ibuf_free(struct ibuf *buf)
182{
183 if (buf == NULL)
184 return;
185 freezero(buf->buf, buf->size);
186 free(buf);
187}
188
189void
190msgbuf_init(struct msgbuf *msgbuf)
191{
192 msgbuf->queued = 0;
193 msgbuf->fd = -1;
194 TAILQ_INIT(&msgbuf->bufs);
195}
196
197void
198msgbuf_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
215void
216msgbuf_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
224int
225msgbuf_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
264again:
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
292static void
293ibuf_enqueue(struct msgbuf *msgbuf, struct ibuf *buf)
294{
295 TAILQ_INSERT_TAIL(&msgbuf->bufs, buf, entry);
296 msgbuf->queued++;
297}
298
299static void
300ibuf_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