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1.1 misho 1: /* $OpenBSD: imsg.c,v 1.15 2017/04/11 09:57:19 reyk 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 <sys/types.h>
20: #include <sys/socket.h>
21: #include <sys/uio.h>
22:
23: #include <errno.h>
24: #include <stdlib.h>
25: #include <string.h>
26: #include <unistd.h>
27:
28: #include "compat.h"
29: #include "imsg.h"
30:
31: int imsg_fd_overhead = 0;
32:
33: int imsg_get_fd(struct imsgbuf *);
34:
35: void
36: imsg_init(struct imsgbuf *ibuf, int fd)
37: {
38: msgbuf_init(&ibuf->w);
39: memset(&ibuf->r, 0, sizeof(ibuf->r));
40: ibuf->fd = fd;
41: ibuf->w.fd = fd;
42: ibuf->pid = getpid();
43: TAILQ_INIT(&ibuf->fds);
44: }
45:
46: ssize_t
47: imsg_read(struct imsgbuf *ibuf)
48: {
49: struct msghdr msg;
50: struct cmsghdr *cmsg;
51: union {
52: struct cmsghdr hdr;
53: char buf[CMSG_SPACE(sizeof(int) * 1)];
54: } cmsgbuf;
55: struct iovec iov;
56: ssize_t n = -1;
57: int fd;
58: struct imsg_fd *ifd;
59:
60: memset(&msg, 0, sizeof(msg));
61: memset(&cmsgbuf, 0, sizeof(cmsgbuf));
62:
63: iov.iov_base = ibuf->r.buf + ibuf->r.wpos;
64: iov.iov_len = sizeof(ibuf->r.buf) - ibuf->r.wpos;
65: msg.msg_iov = &iov;
66: msg.msg_iovlen = 1;
67: msg.msg_control = &cmsgbuf.buf;
68: msg.msg_controllen = sizeof(cmsgbuf.buf);
69:
70: if ((ifd = calloc(1, sizeof(struct imsg_fd))) == NULL)
71: return (-1);
72:
73: again:
74: if (getdtablecount() + imsg_fd_overhead +
75: (int)((CMSG_SPACE(sizeof(int))-CMSG_SPACE(0))/sizeof(int))
76: >= getdtablesize()) {
77: errno = EAGAIN;
78: free(ifd);
79: return (-1);
80: }
81:
82: if ((n = recvmsg(ibuf->fd, &msg, 0)) == -1) {
83: if (errno == EINTR)
84: goto again;
85: goto fail;
86: }
87:
88: ibuf->r.wpos += n;
89:
90: for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL;
91: cmsg = CMSG_NXTHDR(&msg, cmsg)) {
92: if (cmsg->cmsg_level == SOL_SOCKET &&
93: cmsg->cmsg_type == SCM_RIGHTS) {
94: int i;
95: int j;
96:
97: /*
98: * We only accept one file descriptor. Due to C
99: * padding rules, our control buffer might contain
100: * more than one fd, and we must close them.
101: */
102: j = ((char *)cmsg + cmsg->cmsg_len -
103: (char *)CMSG_DATA(cmsg)) / sizeof(int);
104: for (i = 0; i < j; i++) {
105: fd = ((int *)CMSG_DATA(cmsg))[i];
106: if (ifd != NULL) {
107: ifd->fd = fd;
108: TAILQ_INSERT_TAIL(&ibuf->fds, ifd,
109: entry);
110: ifd = NULL;
111: } else
112: close(fd);
113: }
114: }
115: /* we do not handle other ctl data level */
116: }
117:
118: fail:
119: free(ifd);
120: return (n);
121: }
122:
123: ssize_t
124: imsg_get(struct imsgbuf *ibuf, struct imsg *imsg)
125: {
126: size_t av, left, datalen;
127:
128: av = ibuf->r.wpos;
129:
130: if (IMSG_HEADER_SIZE > av)
131: return (0);
132:
133: memcpy(&imsg->hdr, ibuf->r.buf, sizeof(imsg->hdr));
134: if (imsg->hdr.len < IMSG_HEADER_SIZE ||
135: imsg->hdr.len > MAX_IMSGSIZE) {
136: errno = ERANGE;
137: return (-1);
138: }
139: if (imsg->hdr.len > av)
140: return (0);
141: datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
142: ibuf->r.rptr = ibuf->r.buf + IMSG_HEADER_SIZE;
143: if (datalen == 0)
144: imsg->data = NULL;
145: else if ((imsg->data = malloc(datalen)) == NULL)
146: return (-1);
147:
148: if (imsg->hdr.flags & IMSGF_HASFD)
149: imsg->fd = imsg_get_fd(ibuf);
150: else
151: imsg->fd = -1;
152:
153: memcpy(imsg->data, ibuf->r.rptr, datalen);
154:
155: if (imsg->hdr.len < av) {
156: left = av - imsg->hdr.len;
157: memmove(&ibuf->r.buf, ibuf->r.buf + imsg->hdr.len, left);
158: ibuf->r.wpos = left;
159: } else
160: ibuf->r.wpos = 0;
161:
162: return (datalen + IMSG_HEADER_SIZE);
163: }
164:
165: int
166: imsg_compose(struct imsgbuf *ibuf, uint32_t type, uint32_t peerid, pid_t pid,
167: int fd, const void *data, uint16_t datalen)
168: {
169: struct ibuf *wbuf;
170:
171: if ((wbuf = imsg_create(ibuf, type, peerid, pid, datalen)) == NULL)
172: return (-1);
173:
174: if (imsg_add(wbuf, data, datalen) == -1)
175: return (-1);
176:
177: wbuf->fd = fd;
178:
179: imsg_close(ibuf, wbuf);
180:
181: return (1);
182: }
183:
184: int
185: imsg_composev(struct imsgbuf *ibuf, uint32_t type, uint32_t peerid, pid_t pid,
186: int fd, const struct iovec *iov, int iovcnt)
187: {
188: struct ibuf *wbuf;
189: int i, datalen = 0;
190:
191: for (i = 0; i < iovcnt; i++)
192: datalen += iov[i].iov_len;
193:
194: if ((wbuf = imsg_create(ibuf, type, peerid, pid, datalen)) == NULL)
195: return (-1);
196:
197: for (i = 0; i < iovcnt; i++)
198: if (imsg_add(wbuf, iov[i].iov_base, iov[i].iov_len) == -1)
199: return (-1);
200:
201: wbuf->fd = fd;
202:
203: imsg_close(ibuf, wbuf);
204:
205: return (1);
206: }
207:
208: /* ARGSUSED */
209: struct ibuf *
210: imsg_create(struct imsgbuf *ibuf, uint32_t type, uint32_t peerid, pid_t pid,
211: uint16_t datalen)
212: {
213: struct ibuf *wbuf;
214: struct imsg_hdr hdr;
215:
216: datalen += IMSG_HEADER_SIZE;
217: if (datalen > MAX_IMSGSIZE) {
218: errno = ERANGE;
219: return (NULL);
220: }
221:
222: hdr.type = type;
223: hdr.flags = 0;
224: hdr.peerid = peerid;
225: if ((hdr.pid = pid) == 0)
226: hdr.pid = ibuf->pid;
227: if ((wbuf = ibuf_dynamic(datalen, MAX_IMSGSIZE)) == NULL) {
228: return (NULL);
229: }
230: if (imsg_add(wbuf, &hdr, sizeof(hdr)) == -1)
231: return (NULL);
232:
233: return (wbuf);
234: }
235:
236: int
237: imsg_add(struct ibuf *msg, const void *data, uint16_t datalen)
238: {
239: if (datalen)
240: if (ibuf_add(msg, data, datalen) == -1) {
241: ibuf_free(msg);
242: return (-1);
243: }
244: return (datalen);
245: }
246:
247: void
248: imsg_close(struct imsgbuf *ibuf, struct ibuf *msg)
249: {
250: struct imsg_hdr *hdr;
251:
252: hdr = (struct imsg_hdr *)msg->buf;
253:
254: hdr->flags &= ~IMSGF_HASFD;
255: if (msg->fd != -1)
256: hdr->flags |= IMSGF_HASFD;
257:
258: hdr->len = (uint16_t)msg->wpos;
259:
260: ibuf_close(&ibuf->w, msg);
261: }
262:
263: void
264: imsg_free(struct imsg *imsg)
265: {
266: freezero(imsg->data, imsg->hdr.len - IMSG_HEADER_SIZE);
267: }
268:
269: int
270: imsg_get_fd(struct imsgbuf *ibuf)
271: {
272: int fd;
273: struct imsg_fd *ifd;
274:
275: if ((ifd = TAILQ_FIRST(&ibuf->fds)) == NULL)
276: return (-1);
277:
278: fd = ifd->fd;
279: TAILQ_REMOVE(&ibuf->fds, ifd, entry);
280: free(ifd);
281:
282: return (fd);
283: }
284:
285: int
286: imsg_flush(struct imsgbuf *ibuf)
287: {
288: while (ibuf->w.queued)
289: if (msgbuf_write(&ibuf->w) <= 0)
290: return (-1);
291: return (0);
292: }
293:
294: void
295: imsg_clear(struct imsgbuf *ibuf)
296: {
297: int fd;
298:
299: msgbuf_clear(&ibuf->w);
300: while ((fd = imsg_get_fd(ibuf)) != -1)
301: close(fd);
302: }