1 /* $OpenBSD: imsg-buffer.c,v 1.7 2015/07/12 18:40:49 nicm 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 <limits.h> 27 #include <errno.h> 28 #include <stdlib.h> 29 #include <string.h> 30 #include <unistd.h> 31 32 #include "imsg.h" 33 34 int ibuf_realloc(struct ibuf *, size_t); 35 void ibuf_enqueue(struct msgbuf *, struct ibuf *); 36 void ibuf_dequeue(struct msgbuf *, struct ibuf *); 37 38 struct ibuf * 39 ibuf_open(size_t len) 40 { 41 struct ibuf *buf; 42 43 if ((buf = calloc(1, sizeof(struct ibuf))) == NULL) 44 return (NULL); 45 if ((buf->buf = malloc(len)) == NULL) { 46 free(buf); 47 return (NULL); 48 } 49 buf->size = buf->max = len; 50 buf->fd = -1; 51 52 return (buf); 53 } 54 55 struct ibuf * 56 ibuf_dynamic(size_t len, size_t max) 57 { 58 struct ibuf *buf; 59 60 if (max < len) 61 return (NULL); 62 63 if ((buf = ibuf_open(len)) == NULL) 64 return (NULL); 65 66 if (max > 0) 67 buf->max = max; 68 69 return (buf); 70 } 71 72 int 73 ibuf_realloc(struct ibuf *buf, size_t len) 74 { 75 u_char *b; 76 77 /* on static buffers max is eq size and so the following fails */ 78 if (buf->wpos + len > buf->max) { 79 errno = ERANGE; 80 return (-1); 81 } 82 83 b = realloc(buf->buf, buf->wpos + len); 84 if (b == NULL) 85 return (-1); 86 buf->buf = b; 87 buf->size = buf->wpos + len; 88 89 return (0); 90 } 91 92 int 93 ibuf_add(struct ibuf *buf, const void *data, size_t len) 94 { 95 if (buf->wpos + len > buf->size) 96 if (ibuf_realloc(buf, len) == -1) 97 return (-1); 98 99 memcpy(buf->buf + buf->wpos, data, len); 100 buf->wpos += len; 101 return (0); 102 } 103 104 void * 105 ibuf_reserve(struct ibuf *buf, size_t len) 106 { 107 void *b; 108 109 if (buf->wpos + len > buf->size) 110 if (ibuf_realloc(buf, len) == -1) 111 return (NULL); 112 113 b = buf->buf + buf->wpos; 114 buf->wpos += len; 115 return (b); 116 } 117 118 void * 119 ibuf_seek(struct ibuf *buf, size_t pos, size_t len) 120 { 121 /* only allowed to seek in already written parts */ 122 if (pos + len > buf->wpos) 123 return (NULL); 124 125 return (buf->buf + pos); 126 } 127 128 size_t 129 ibuf_size(struct ibuf *buf) 130 { 131 return (buf->wpos); 132 } 133 134 size_t 135 ibuf_left(struct ibuf *buf) 136 { 137 return (buf->max - buf->wpos); 138 } 139 140 void 141 ibuf_close(struct msgbuf *msgbuf, struct ibuf *buf) 142 { 143 ibuf_enqueue(msgbuf, buf); 144 } 145 146 int 147 ibuf_write(struct msgbuf *msgbuf) 148 { 149 struct iovec iov[IOV_MAX]; 150 struct ibuf *buf; 151 unsigned int i = 0; 152 ssize_t n; 153 154 memset(&iov, 0, sizeof(iov)); 155 TAILQ_FOREACH(buf, &msgbuf->bufs, entry) { 156 if (i >= IOV_MAX) 157 break; 158 iov[i].iov_base = buf->buf + buf->rpos; 159 iov[i].iov_len = buf->wpos - buf->rpos; 160 i++; 161 } 162 163 again: 164 if ((n = writev(msgbuf->fd, iov, i)) == -1) { 165 if (errno == EINTR) 166 goto again; 167 if (errno == ENOBUFS) 168 errno = EAGAIN; 169 return (-1); 170 } 171 172 if (n == 0) { /* connection closed */ 173 errno = 0; 174 return (0); 175 } 176 177 msgbuf_drain(msgbuf, n); 178 179 return (1); 180 } 181 182 void 183 ibuf_free(struct ibuf *buf) 184 { 185 free(buf->buf); 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 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 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