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 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 32int ibuf_realloc(struct ibuf *, size_t); 33void ibuf_enqueue(struct msgbuf *, struct ibuf *); 34void ibuf_dequeue(struct msgbuf *, struct ibuf *); 35 36struct ibuf * 37ibuf_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 53struct ibuf * 54ibuf_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 70int 71ibuf_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 90int 91ibuf_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 102void * 103ibuf_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 116void * 117ibuf_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 126size_t 127ibuf_size(struct ibuf *buf) 128{ 129 return (buf->wpos); 130} 131 132size_t 133ibuf_left(struct ibuf *buf) 134{ 135 return (buf->max - buf->wpos); 136} 137 138void 139ibuf_close(struct msgbuf *msgbuf, struct ibuf *buf) 140{ 141 ibuf_enqueue(msgbuf, buf); 142} 143 144int 145ibuf_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 memset(&iov, 0, 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 161again: 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 180void 181ibuf_free(struct ibuf *buf) 182{ 183 free(buf->buf); 184 free(buf); 185} 186 187void 188msgbuf_init(struct msgbuf *msgbuf) 189{ 190 msgbuf->queued = 0; 191 msgbuf->fd = -1; 192 TAILQ_INIT(&msgbuf->bufs); 193} 194 195void 196msgbuf_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 213void 214msgbuf_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 222int 223msgbuf_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 memset(&iov, 0, sizeof(iov)); 237 memset(&msg, 0, sizeof(msg)); 238 memset(&cmsgbuf, 0, sizeof(cmsgbuf)); 239 TAILQ_FOREACH(buf, &msgbuf->bufs, entry) { 240 if (i >= IOV_MAX) 241 break; 242 iov[i].iov_base = buf->buf + buf->rpos; 243 iov[i].iov_len = buf->wpos - buf->rpos; 244 i++; 245 if (buf->fd != -1) 246 break; 247 } 248 249 msg.msg_iov = iov; 250 msg.msg_iovlen = i; 251 252 if (buf != NULL && buf->fd != -1) { 253 msg.msg_control = (caddr_t)&cmsgbuf.buf; 254 msg.msg_controllen = sizeof(cmsgbuf.buf); 255 cmsg = CMSG_FIRSTHDR(&msg); 256 cmsg->cmsg_len = CMSG_LEN(sizeof(int)); 257 cmsg->cmsg_level = SOL_SOCKET; 258 cmsg->cmsg_type = SCM_RIGHTS; 259 *(int *)CMSG_DATA(cmsg) = buf->fd; 260 } 261 262again: 263 if ((n = sendmsg(msgbuf->fd, &msg, 0)) == -1) { 264 if (errno == EINTR) 265 goto again; 266 if (errno == ENOBUFS) 267 errno = EAGAIN; 268 return (-1); 269 } 270 271 if (n == 0) { /* connection closed */ 272 errno = 0; 273 return (0); 274 } 275 276 /* 277 * assumption: fd got sent if sendmsg sent anything 278 * this works because fds are passed one at a time 279 */ 280 if (buf != NULL && buf->fd != -1) { 281 close(buf->fd); 282 buf->fd = -1; 283 } 284 285 msgbuf_drain(msgbuf, n); 286 287 return (1); 288} 289 290void 291ibuf_enqueue(struct msgbuf *msgbuf, struct ibuf *buf) 292{ 293 TAILQ_INSERT_TAIL(&msgbuf->bufs, buf, entry); 294 msgbuf->queued++; 295} 296 297void 298ibuf_dequeue(struct msgbuf *msgbuf, struct ibuf *buf) 299{ 300 TAILQ_REMOVE(&msgbuf->bufs, buf, entry); 301 302 if (buf->fd != -1) 303 close(buf->fd); 304 305 msgbuf->queued--; 306 ibuf_free(buf); 307} 308