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 | |
32 | static int ibuf_realloc(struct ibuf *, size_t); |
33 | static void ibuf_enqueue(struct msgbuf *, struct ibuf *); |
34 | static void ibuf_dequeue(struct msgbuf *, struct ibuf *); |
35 | |
36 | struct ibuf * |
37 | ibuf_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 | |
53 | struct ibuf * |
54 | ibuf_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 | |
70 | static int |
71 | ibuf_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 | |
90 | int |
91 | ibuf_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 | |
102 | void * |
103 | ibuf_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 | |
116 | void * |
117 | ibuf_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 | |
126 | size_t |
127 | ibuf_size(struct ibuf *buf) |
128 | { |
129 | return (buf->wpos); |
130 | } |
131 | |
132 | size_t |
133 | ibuf_left(struct ibuf *buf) |
134 | { |
135 | return (buf->max - buf->wpos); |
136 | } |
137 | |
138 | void |
139 | ibuf_close(struct msgbuf *msgbuf, struct ibuf *buf) |
140 | { |
141 | ibuf_enqueue(msgbuf, buf); |
142 | } |
143 | |
144 | int |
145 | ibuf_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 | |
161 | again: |
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 | |
180 | void |
181 | ibuf_free(struct ibuf *buf) |
182 | { |
183 | if (buf == NULL) |
184 | return; |
185 | freezero(buf->buf, buf->size); |
186 | free(buf); |
187 | } |
188 | |
189 | void |
190 | msgbuf_init(struct msgbuf *msgbuf) |
191 | { |
192 | msgbuf->queued = 0; |
193 | msgbuf->fd = -1; |
194 | TAILQ_INIT(&msgbuf->bufs); |
195 | } |
196 | |
197 | void |
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 |
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 |
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 | static void |
293 | ibuf_enqueue(struct msgbuf *msgbuf, struct ibuf *buf) |
294 | { |
295 | TAILQ_INSERT_TAIL(&msgbuf->bufs, buf, entry); |
296 | msgbuf->queued++; |
297 | } |
298 | |
299 | static void |
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 | |