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 * $FreeBSD$ 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 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 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 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 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 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 * 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 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 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 266 imsg_free(struct imsg *imsg) 267 { 268 free(imsg->data); 269 } 270 271 int 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 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 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