1 /* $OpenBSD: imsg.c,v 1.13 2015/12/09 11:54:12 tb 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.c 292023 2015-12-09 19:22:20Z 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 <errno.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <unistd.h>
30
31 #include "imsg.h"
32
33 int imsg_fd_overhead = 0;
34
35 int imsg_get_fd(struct imsgbuf *);
36
37 void
imsg_init(struct imsgbuf * ibuf,int fd)38 imsg_init(struct imsgbuf *ibuf, int fd)
39 {
40 msgbuf_init(&ibuf->w);
41 memset(&ibuf->r, 0, sizeof(ibuf->r));
42 ibuf->fd = fd;
43 ibuf->w.fd = fd;
44 ibuf->pid = getpid();
45 TAILQ_INIT(&ibuf->fds);
46 }
47
48 ssize_t
imsg_read(struct imsgbuf * ibuf)49 imsg_read(struct imsgbuf *ibuf)
50 {
51 struct msghdr msg;
52 struct cmsghdr *cmsg;
53 union {
54 struct cmsghdr hdr;
55 char buf[CMSG_SPACE(sizeof(int) * 1)];
56 } cmsgbuf;
57 struct iovec iov;
58 ssize_t n = -1;
59 int fd;
60 struct imsg_fd *ifd;
61
62 memset(&msg, 0, sizeof(msg));
63 memset(&cmsgbuf, 0, sizeof(cmsgbuf));
64
65 iov.iov_base = ibuf->r.buf + ibuf->r.wpos;
66 iov.iov_len = sizeof(ibuf->r.buf) - ibuf->r.wpos;
67 msg.msg_iov = &iov;
68 msg.msg_iovlen = 1;
69 msg.msg_control = &cmsgbuf.buf;
70 msg.msg_controllen = sizeof(cmsgbuf.buf);
71
72 if ((ifd = calloc(1, sizeof(struct imsg_fd))) == NULL)
73 return (-1);
74
75 again:
76 if (getdtablecount() + imsg_fd_overhead +
77 (int)((CMSG_SPACE(sizeof(int))-CMSG_SPACE(0))/sizeof(int))
78 >= getdtablesize()) {
79 errno = EAGAIN;
80 free(ifd);
81 return (-1);
82 }
83
84 if ((n = recvmsg(ibuf->fd, &msg, 0)) == -1) {
85 if (errno == EINTR)
86 goto again;
87 goto fail;
88 }
89
90 ibuf->r.wpos += n;
91
92 for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL;
93 cmsg = CMSG_NXTHDR(&msg, cmsg)) {
94 if (cmsg->cmsg_level == SOL_SOCKET &&
95 cmsg->cmsg_type == SCM_RIGHTS) {
96 int i;
97 int j;
98
99 /*
100 * We only accept one file descriptor. Due to C
101 * padding rules, our control buffer might contain
102 * more than one fd, and we must close them.
103 */
104 j = ((char *)cmsg + cmsg->cmsg_len -
105 (char *)CMSG_DATA(cmsg)) / sizeof(int);
106 for (i = 0; i < j; i++) {
107 fd = ((int *)CMSG_DATA(cmsg))[i];
108 if (ifd != NULL) {
109 ifd->fd = fd;
110 TAILQ_INSERT_TAIL(&ibuf->fds, ifd,
111 entry);
112 ifd = NULL;
113 } else
114 close(fd);
115 }
116 }
117 /* we do not handle other ctl data level */
118 }
119
120 fail:
121 free(ifd);
122 return (n);
123 }
124
125 ssize_t
imsg_get(struct imsgbuf * ibuf,struct imsg * imsg)126 imsg_get(struct imsgbuf *ibuf, struct imsg *imsg)
127 {
128 size_t av, left, datalen;
129
130 av = ibuf->r.wpos;
131
132 if (IMSG_HEADER_SIZE > av)
133 return (0);
134
135 memcpy(&imsg->hdr, ibuf->r.buf, sizeof(imsg->hdr));
136 if (imsg->hdr.len < IMSG_HEADER_SIZE ||
137 imsg->hdr.len > MAX_IMSGSIZE) {
138 errno = ERANGE;
139 return (-1);
140 }
141 if (imsg->hdr.len > av)
142 return (0);
143 datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
144 ibuf->r.rptr = ibuf->r.buf + IMSG_HEADER_SIZE;
145 if (datalen == 0)
146 imsg->data = NULL;
147 else if ((imsg->data = malloc(datalen)) == NULL)
148 return (-1);
149
150 if (imsg->hdr.flags & IMSGF_HASFD)
151 imsg->fd = imsg_get_fd(ibuf);
152 else
153 imsg->fd = -1;
154
155 memcpy(imsg->data, ibuf->r.rptr, datalen);
156
157 if (imsg->hdr.len < av) {
158 left = av - imsg->hdr.len;
159 memmove(&ibuf->r.buf, ibuf->r.buf + imsg->hdr.len, left);
160 ibuf->r.wpos = left;
161 } else
162 ibuf->r.wpos = 0;
163
164 return (datalen + IMSG_HEADER_SIZE);
165 }
166
167 int
imsg_compose(struct imsgbuf * ibuf,u_int32_t type,u_int32_t peerid,pid_t pid,int fd,const void * data,u_int16_t datalen)168 imsg_compose(struct imsgbuf *ibuf, u_int32_t type, u_int32_t peerid,
169 pid_t pid, int fd, const void *data, u_int16_t datalen)
170 {
171 struct ibuf *wbuf;
172
173 if ((wbuf = imsg_create(ibuf, type, peerid, pid, datalen)) == NULL)
174 return (-1);
175
176 if (imsg_add(wbuf, data, datalen) == -1)
177 return (-1);
178
179 wbuf->fd = fd;
180
181 imsg_close(ibuf, wbuf);
182
183 return (1);
184 }
185
186 int
imsg_composev(struct imsgbuf * ibuf,u_int32_t type,u_int32_t peerid,pid_t pid,int fd,const struct iovec * iov,int iovcnt)187 imsg_composev(struct imsgbuf *ibuf, u_int32_t type, u_int32_t peerid,
188 pid_t pid, int fd, const struct iovec *iov, int iovcnt)
189 {
190 struct ibuf *wbuf;
191 int i, datalen = 0;
192
193 for (i = 0; i < iovcnt; i++)
194 datalen += iov[i].iov_len;
195
196 if ((wbuf = imsg_create(ibuf, type, peerid, pid, datalen)) == NULL)
197 return (-1);
198
199 for (i = 0; i < iovcnt; i++)
200 if (imsg_add(wbuf, iov[i].iov_base, iov[i].iov_len) == -1)
201 return (-1);
202
203 wbuf->fd = fd;
204
205 imsg_close(ibuf, wbuf);
206
207 return (1);
208 }
209
210 /* ARGSUSED */
211 struct ibuf *
imsg_create(struct imsgbuf * ibuf,u_int32_t type,u_int32_t peerid,pid_t pid,u_int16_t datalen)212 imsg_create(struct imsgbuf *ibuf, u_int32_t type, u_int32_t peerid,
213 pid_t pid, u_int16_t datalen)
214 {
215 struct ibuf *wbuf;
216 struct imsg_hdr hdr;
217
218 datalen += IMSG_HEADER_SIZE;
219 if (datalen > MAX_IMSGSIZE) {
220 errno = ERANGE;
221 return (NULL);
222 }
223
224 hdr.type = type;
225 hdr.flags = 0;
226 hdr.peerid = peerid;
227 if ((hdr.pid = pid) == 0)
228 hdr.pid = ibuf->pid;
229 if ((wbuf = ibuf_dynamic(datalen, MAX_IMSGSIZE)) == NULL) {
230 return (NULL);
231 }
232 if (imsg_add(wbuf, &hdr, sizeof(hdr)) == -1)
233 return (NULL);
234
235 return (wbuf);
236 }
237
238 int
imsg_add(struct ibuf * msg,const void * data,u_int16_t datalen)239 imsg_add(struct ibuf *msg, const void *data, u_int16_t datalen)
240 {
241 if (datalen)
242 if (ibuf_add(msg, data, datalen) == -1) {
243 ibuf_free(msg);
244 return (-1);
245 }
246 return (datalen);
247 }
248
249 void
imsg_close(struct imsgbuf * ibuf,struct ibuf * msg)250 imsg_close(struct imsgbuf *ibuf, struct ibuf *msg)
251 {
252 struct imsg_hdr *hdr;
253
254 hdr = (struct imsg_hdr *)msg->buf;
255
256 hdr->flags &= ~IMSGF_HASFD;
257 if (msg->fd != -1)
258 hdr->flags |= IMSGF_HASFD;
259
260 hdr->len = (u_int16_t)msg->wpos;
261
262 ibuf_close(&ibuf->w, msg);
263 }
264
265 void
imsg_free(struct imsg * imsg)266 imsg_free(struct imsg *imsg)
267 {
268 free(imsg->data);
269 }
270
271 int
imsg_get_fd(struct imsgbuf * ibuf)272 imsg_get_fd(struct imsgbuf *ibuf)
273 {
274 int fd;
275 struct imsg_fd *ifd;
276
277 if ((ifd = TAILQ_FIRST(&ibuf->fds)) == NULL)
278 return (-1);
279
280 fd = ifd->fd;
281 TAILQ_REMOVE(&ibuf->fds, ifd, entry);
282 free(ifd);
283
284 return (fd);
285 }
286
287 int
imsg_flush(struct imsgbuf * ibuf)288 imsg_flush(struct imsgbuf *ibuf)
289 {
290 while (ibuf->w.queued)
291 if (msgbuf_write(&ibuf->w) <= 0)
292 return (-1);
293 return (0);
294 }
295
296 void
imsg_clear(struct imsgbuf * ibuf)297 imsg_clear(struct imsgbuf *ibuf)
298 {
299 int fd;
300
301 msgbuf_clear(&ibuf->w);
302 while ((fd = imsg_get_fd(ibuf)) != -1)
303 close(fd);
304 }
305