proto_common.c revision 220273
1/*- 2 * Copyright (c) 2009-2010 The FreeBSD Foundation 3 * Copyright (c) 2011 Pawel Jakub Dawidek <pawel@dawidek.net> 4 * All rights reserved. 5 * 6 * This software was developed by Pawel Jakub Dawidek under sponsorship from 7 * the FreeBSD Foundation. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31#include <sys/cdefs.h> 32__FBSDID("$FreeBSD: head/sbin/hastd/proto_common.c 220273 2011-04-02 09:31:02Z pjd $"); 33 34#include <sys/types.h> 35#include <sys/socket.h> 36 37#include <errno.h> 38#include <fcntl.h> 39#include <stdbool.h> 40#include <stdlib.h> 41#include <strings.h> 42#include <unistd.h> 43 44#include "pjdlog.h" 45#include "proto_impl.h" 46 47/* Maximum size of packet we want to use when sending data. */ 48#ifndef MAX_SEND_SIZE 49#define MAX_SEND_SIZE 32768 50#endif 51 52static bool 53blocking_socket(int sock) 54{ 55 int flags; 56 57 flags = fcntl(sock, F_GETFL); 58 PJDLOG_ASSERT(flags >= 0); 59 return ((flags & O_NONBLOCK) == 0); 60} 61 62static int 63proto_descriptor_send(int sock, int fd) 64{ 65 unsigned char ctrl[CMSG_SPACE(sizeof(fd))]; 66 struct msghdr msg; 67 struct cmsghdr *cmsg; 68 69 PJDLOG_ASSERT(sock >= 0); 70 PJDLOG_ASSERT(fd >= 0); 71 72 bzero(&msg, sizeof(msg)); 73 bzero(&ctrl, sizeof(ctrl)); 74 75 msg.msg_iov = NULL; 76 msg.msg_iovlen = 0; 77 msg.msg_control = ctrl; 78 msg.msg_controllen = sizeof(ctrl); 79 80 cmsg = CMSG_FIRSTHDR(&msg); 81 cmsg->cmsg_level = SOL_SOCKET; 82 cmsg->cmsg_type = SCM_RIGHTS; 83 cmsg->cmsg_len = CMSG_LEN(sizeof(fd)); 84 bcopy(&fd, CMSG_DATA(cmsg), sizeof(fd)); 85 86 if (sendmsg(sock, &msg, 0) == -1) 87 return (errno); 88 89 return (0); 90} 91 92int 93proto_common_send(int sock, const unsigned char *data, size_t size, int fd) 94{ 95 ssize_t done; 96 size_t sendsize; 97 int errcount = 0; 98 99 PJDLOG_ASSERT(sock >= 0); 100 101 if (data == NULL) { 102 /* The caller is just trying to decide about direction. */ 103 104 PJDLOG_ASSERT(size == 0); 105 106 if (shutdown(sock, SHUT_RD) == -1) 107 return (errno); 108 return (0); 109 } 110 111 PJDLOG_ASSERT(data != NULL); 112 PJDLOG_ASSERT(size > 0); 113 114 do { 115 sendsize = size < MAX_SEND_SIZE ? size : MAX_SEND_SIZE; 116 done = send(sock, data, sendsize, MSG_NOSIGNAL); 117 if (done == 0) { 118 return (ENOTCONN); 119 } else if (done < 0) { 120 if (errno == EINTR) 121 continue; 122 if (errno == ENOBUFS) { 123 /* 124 * If there are no buffers we retry. 125 * After each try we increase delay before the 126 * next one and we give up after fifteen times. 127 * This gives 11s of total wait time. 128 */ 129 if (errcount == 15) { 130 pjdlog_warning("Getting ENOBUFS errors for 11s on send(), giving up."); 131 } else { 132 if (errcount == 0) 133 pjdlog_warning("Got ENOBUFS error on send(), retrying for a bit."); 134 errcount++; 135 usleep(100000 * errcount); 136 continue; 137 } 138 } 139 /* 140 * If this is blocking socket and we got EAGAIN, this 141 * means the request timed out. Translate errno to 142 * ETIMEDOUT, to give administrator a hint to 143 * eventually increase timeout. 144 */ 145 if (errno == EAGAIN && blocking_socket(sock)) 146 errno = ETIMEDOUT; 147 return (errno); 148 } 149 data += done; 150 size -= done; 151 } while (size > 0); 152 if (errcount > 0) { 153 pjdlog_info("Data sent successfully after %d ENOBUFS error%s.", 154 errcount, errcount == 1 ? "" : "s"); 155 } 156 157 if (fd == -1) 158 return (0); 159 return (proto_descriptor_send(sock, fd)); 160} 161 162static int 163proto_descriptor_recv(int sock, int *fdp) 164{ 165 unsigned char ctrl[CMSG_SPACE(sizeof(*fdp))]; 166 struct msghdr msg; 167 struct cmsghdr *cmsg; 168 169 PJDLOG_ASSERT(sock >= 0); 170 PJDLOG_ASSERT(fdp != NULL); 171 172 bzero(&msg, sizeof(msg)); 173 bzero(&ctrl, sizeof(ctrl)); 174 175 msg.msg_iov = NULL; 176 msg.msg_iovlen = 0; 177 msg.msg_control = ctrl; 178 msg.msg_controllen = sizeof(ctrl); 179 180 if (recvmsg(sock, &msg, 0) == -1) 181 return (errno); 182 183 cmsg = CMSG_FIRSTHDR(&msg); 184 if (cmsg->cmsg_level != SOL_SOCKET || 185 cmsg->cmsg_type != SCM_RIGHTS) { 186 return (EINVAL); 187 } 188 bcopy(CMSG_DATA(cmsg), fdp, sizeof(*fdp)); 189 190 return (0); 191} 192 193int 194proto_common_recv(int sock, unsigned char *data, size_t size, int *fdp) 195{ 196 ssize_t done; 197 198 PJDLOG_ASSERT(sock >= 0); 199 200 if (data == NULL) { 201 /* The caller is just trying to decide about direction. */ 202 203 PJDLOG_ASSERT(size == 0); 204 205 if (shutdown(sock, SHUT_WR) == -1) 206 return (errno); 207 return (0); 208 } 209 210 PJDLOG_ASSERT(data != NULL); 211 PJDLOG_ASSERT(size > 0); 212 213 do { 214 done = recv(sock, data, size, MSG_WAITALL); 215 } while (done == -1 && errno == EINTR); 216 if (done == 0) { 217 return (ENOTCONN); 218 } else if (done < 0) { 219 /* 220 * If this is blocking socket and we got EAGAIN, this 221 * means the request timed out. Translate errno to 222 * ETIMEDOUT, to give administrator a hint to 223 * eventually increase timeout. 224 */ 225 if (errno == EAGAIN && blocking_socket(sock)) 226 errno = ETIMEDOUT; 227 return (errno); 228 } 229 if (fdp == NULL) 230 return (0); 231 return (proto_descriptor_recv(sock, fdp)); 232} 233