1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2009-2010 The FreeBSD Foundation 5 * Copyright (c) 2011 Pawel Jakub Dawidek <pawel@dawidek.net> 6 * All rights reserved. 7 * 8 * This software was developed by Pawel Jakub Dawidek under sponsorship from 9 * the FreeBSD Foundation. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <sys/cdefs.h> 34 __FBSDID("$FreeBSD$"); 35 36 #include <sys/types.h> 37 #include <sys/socket.h> 38 39 #include <errno.h> 40 #include <fcntl.h> 41 #include <stdbool.h> 42 #include <stdlib.h> 43 #include <strings.h> 44 #include <unistd.h> 45 46 #include "pjdlog.h" 47 #include "proto_impl.h" 48 49 /* Maximum size of packet we want to use when sending data. */ 50 #ifndef MAX_SEND_SIZE 51 #define MAX_SEND_SIZE 32768 52 #endif 53 54 static bool 55 blocking_socket(int sock) 56 { 57 int flags; 58 59 flags = fcntl(sock, F_GETFL); 60 PJDLOG_ASSERT(flags >= 0); 61 return ((flags & O_NONBLOCK) == 0); 62 } 63 64 static int 65 proto_descriptor_send(int sock, int fd) 66 { 67 unsigned char ctrl[CMSG_SPACE(sizeof(fd))]; 68 struct msghdr msg; 69 struct cmsghdr *cmsg; 70 71 PJDLOG_ASSERT(sock >= 0); 72 PJDLOG_ASSERT(fd >= 0); 73 74 bzero(&msg, sizeof(msg)); 75 bzero(&ctrl, sizeof(ctrl)); 76 77 msg.msg_iov = NULL; 78 msg.msg_iovlen = 0; 79 msg.msg_control = ctrl; 80 msg.msg_controllen = sizeof(ctrl); 81 82 cmsg = CMSG_FIRSTHDR(&msg); 83 cmsg->cmsg_level = SOL_SOCKET; 84 cmsg->cmsg_type = SCM_RIGHTS; 85 cmsg->cmsg_len = CMSG_LEN(sizeof(fd)); 86 bcopy(&fd, CMSG_DATA(cmsg), sizeof(fd)); 87 88 if (sendmsg(sock, &msg, 0) == -1) 89 return (errno); 90 91 return (0); 92 } 93 94 int 95 proto_common_send(int sock, const unsigned char *data, size_t size, int fd) 96 { 97 ssize_t done; 98 size_t sendsize; 99 int errcount = 0; 100 101 PJDLOG_ASSERT(sock >= 0); 102 103 if (data == NULL) { 104 /* The caller is just trying to decide about direction. */ 105 106 PJDLOG_ASSERT(size == 0); 107 108 if (shutdown(sock, SHUT_RD) == -1) 109 return (errno); 110 return (0); 111 } 112 113 PJDLOG_ASSERT(data != NULL); 114 PJDLOG_ASSERT(size > 0); 115 116 do { 117 sendsize = size < MAX_SEND_SIZE ? size : MAX_SEND_SIZE; 118 done = send(sock, data, sendsize, MSG_NOSIGNAL); 119 if (done == 0) { 120 return (ENOTCONN); 121 } else if (done == -1) { 122 if (errno == EINTR) 123 continue; 124 if (errno == ENOBUFS) { 125 /* 126 * If there are no buffers we retry. 127 * After each try we increase delay before the 128 * next one and we give up after fifteen times. 129 * This gives 11s of total wait time. 130 */ 131 if (errcount == 15) { 132 pjdlog_warning("Getting ENOBUFS errors for 11s on send(), giving up."); 133 } else { 134 if (errcount == 0) 135 pjdlog_warning("Got ENOBUFS error on send(), retrying for a bit."); 136 errcount++; 137 usleep(100000 * errcount); 138 continue; 139 } 140 } 141 /* 142 * If this is blocking socket and we got EAGAIN, this 143 * means the request timed out. Translate errno to 144 * ETIMEDOUT, to give administrator a hint to 145 * eventually increase timeout. 146 */ 147 if (errno == EAGAIN && blocking_socket(sock)) 148 errno = ETIMEDOUT; 149 return (errno); 150 } 151 data += done; 152 size -= done; 153 } while (size > 0); 154 if (errcount > 0) { 155 pjdlog_info("Data sent successfully after %d ENOBUFS error%s.", 156 errcount, errcount == 1 ? "" : "s"); 157 } 158 159 if (fd == -1) 160 return (0); 161 return (proto_descriptor_send(sock, fd)); 162 } 163 164 static int 165 proto_descriptor_recv(int sock, int *fdp) 166 { 167 unsigned char ctrl[CMSG_SPACE(sizeof(*fdp))]; 168 struct msghdr msg; 169 struct cmsghdr *cmsg; 170 171 PJDLOG_ASSERT(sock >= 0); 172 PJDLOG_ASSERT(fdp != NULL); 173 174 bzero(&msg, sizeof(msg)); 175 bzero(&ctrl, sizeof(ctrl)); 176 177 msg.msg_iov = NULL; 178 msg.msg_iovlen = 0; 179 msg.msg_control = ctrl; 180 msg.msg_controllen = sizeof(ctrl); 181 182 if (recvmsg(sock, &msg, 0) == -1) 183 return (errno); 184 185 cmsg = CMSG_FIRSTHDR(&msg); 186 if (cmsg == NULL || cmsg->cmsg_level != SOL_SOCKET || 187 cmsg->cmsg_type != SCM_RIGHTS) { 188 return (EINVAL); 189 } 190 bcopy(CMSG_DATA(cmsg), fdp, sizeof(*fdp)); 191 192 return (0); 193 } 194 195 int 196 proto_common_recv(int sock, unsigned char *data, size_t size, int *fdp) 197 { 198 ssize_t done; 199 200 PJDLOG_ASSERT(sock >= 0); 201 202 if (data == NULL) { 203 /* The caller is just trying to decide about direction. */ 204 205 PJDLOG_ASSERT(size == 0); 206 207 if (shutdown(sock, SHUT_WR) == -1) 208 return (errno); 209 return (0); 210 } 211 212 PJDLOG_ASSERT(data != NULL); 213 PJDLOG_ASSERT(size > 0); 214 215 do { 216 done = recv(sock, data, size, MSG_WAITALL); 217 } while (done == -1 && errno == EINTR); 218 if (done == 0) { 219 return (ENOTCONN); 220 } else if (done == -1) { 221 /* 222 * If this is blocking socket and we got EAGAIN, this 223 * means the request timed out. Translate errno to 224 * ETIMEDOUT, to give administrator a hint to 225 * eventually increase timeout. 226 */ 227 if (errno == EAGAIN && blocking_socket(sock)) 228 errno = ETIMEDOUT; 229 return (errno); 230 } 231 if (fdp == NULL) 232 return (0); 233 return (proto_descriptor_recv(sock, fdp)); 234 } 235