1 /* $OpenBSD: imsg-buffer.c,v 1.5 2014/12/25 22:20:52 benno 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/queue.h> 21 #include <sys/socket.h> 22 #include <sys/uio.h> 23 24 #include <limits.h> 25 #include <errno.h> 26 #include <stdlib.h> 27 #include <string.h> 28 #include <unistd.h> 29 30 #include "imsg.h" 31 32 int ibuf_realloc(struct ibuf *, size_t); 33 void ibuf_enqueue(struct msgbuf *, struct ibuf *); 34 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 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 = realloc(buf->buf, buf->wpos + len); 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 bzero(&iov, 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 free(buf->buf); 184 free(buf); 185 } 186 187 void 188 msgbuf_init(struct msgbuf *msgbuf) 189 { 190 msgbuf->queued = 0; 191 msgbuf->fd = -1; 192 TAILQ_INIT(&msgbuf->bufs); 193 } 194 195 void 196 msgbuf_drain(struct msgbuf *msgbuf, size_t n) 197 { 198 struct ibuf *buf, *next; 199 200 for (buf = TAILQ_FIRST(&msgbuf->bufs); buf != NULL && n > 0; 201 buf = next) { 202 next = TAILQ_NEXT(buf, entry); 203 if (buf->rpos + n >= buf->wpos) { 204 n -= buf->wpos - buf->rpos; 205 ibuf_dequeue(msgbuf, buf); 206 } else { 207 buf->rpos += n; 208 n = 0; 209 } 210 } 211 } 212 213 void 214 msgbuf_clear(struct msgbuf *msgbuf) 215 { 216 struct ibuf *buf; 217 218 while ((buf = TAILQ_FIRST(&msgbuf->bufs)) != NULL) 219 ibuf_dequeue(msgbuf, buf); 220 } 221 222 int 223 msgbuf_write(struct msgbuf *msgbuf) 224 { 225 struct iovec iov[IOV_MAX]; 226 struct ibuf *buf; 227 unsigned int i = 0; 228 ssize_t n; 229 struct msghdr msg; 230 struct cmsghdr *cmsg; 231 union { 232 struct cmsghdr hdr; 233 char buf[CMSG_SPACE(sizeof(int))]; 234 } cmsgbuf; 235 236 bzero(&iov, sizeof(iov)); 237 bzero(&msg, sizeof(msg)); 238 TAILQ_FOREACH(buf, &msgbuf->bufs, entry) { 239 if (i >= IOV_MAX) 240 break; 241 iov[i].iov_base = buf->buf + buf->rpos; 242 iov[i].iov_len = buf->wpos - buf->rpos; 243 i++; 244 if (buf->fd != -1) 245 break; 246 } 247 248 msg.msg_iov = iov; 249 msg.msg_iovlen = i; 250 251 if (buf != NULL && buf->fd != -1) { 252 msg.msg_control = (caddr_t)&cmsgbuf.buf; 253 msg.msg_controllen = sizeof(cmsgbuf.buf); 254 cmsg = CMSG_FIRSTHDR(&msg); 255 cmsg->cmsg_len = CMSG_LEN(sizeof(int)); 256 cmsg->cmsg_level = SOL_SOCKET; 257 cmsg->cmsg_type = SCM_RIGHTS; 258 *(int *)CMSG_DATA(cmsg) = buf->fd; 259 } 260 261 again: 262 if ((n = sendmsg(msgbuf->fd, &msg, 0)) == -1) { 263 if (errno == EINTR) 264 goto again; 265 if (errno == ENOBUFS) 266 errno = EAGAIN; 267 return (-1); 268 } 269 270 if (n == 0) { /* connection closed */ 271 errno = 0; 272 return (0); 273 } 274 275 /* 276 * assumption: fd got sent if sendmsg sent anything 277 * this works because fds are passed one at a time 278 */ 279 if (buf != NULL && buf->fd != -1) { 280 close(buf->fd); 281 buf->fd = -1; 282 } 283 284 msgbuf_drain(msgbuf, n); 285 286 return (1); 287 } 288 289 void 290 ibuf_enqueue(struct msgbuf *msgbuf, struct ibuf *buf) 291 { 292 TAILQ_INSERT_TAIL(&msgbuf->bufs, buf, entry); 293 msgbuf->queued++; 294 } 295 296 void 297 ibuf_dequeue(struct msgbuf *msgbuf, struct ibuf *buf) 298 { 299 TAILQ_REMOVE(&msgbuf->bufs, buf, entry); 300 301 if (buf->fd != -1) 302 close(buf->fd); 303 304 msgbuf->queued--; 305 ibuf_free(buf); 306 } 307