1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 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/types.h> 34 #include <sys/socket.h> 35 36 #include <errno.h> 37 #include <fcntl.h> 38 #include <stdbool.h> 39 #include <stdlib.h> 40 #include <strings.h> 41 #include <unistd.h> 42 43 #include "pjdlog.h" 44 #include "proto_impl.h" 45 46 /* Maximum size of packet we want to use when sending data. */ 47 #ifndef MAX_SEND_SIZE 48 #define MAX_SEND_SIZE 32768 49 #endif 50 51 static bool 52 blocking_socket(int sock) 53 { 54 int flags; 55 56 flags = fcntl(sock, F_GETFL); 57 PJDLOG_ASSERT(flags >= 0); 58 return ((flags & O_NONBLOCK) == 0); 59 } 60 61 static int 62 proto_descriptor_send(int sock, int fd) 63 { 64 unsigned char ctrl[CMSG_SPACE(sizeof(fd))]; 65 struct msghdr msg; 66 struct cmsghdr *cmsg; 67 68 PJDLOG_ASSERT(sock >= 0); 69 PJDLOG_ASSERT(fd >= 0); 70 71 bzero(&msg, sizeof(msg)); 72 bzero(&ctrl, sizeof(ctrl)); 73 74 msg.msg_iov = NULL; 75 msg.msg_iovlen = 0; 76 msg.msg_control = ctrl; 77 msg.msg_controllen = sizeof(ctrl); 78 79 cmsg = CMSG_FIRSTHDR(&msg); 80 cmsg->cmsg_level = SOL_SOCKET; 81 cmsg->cmsg_type = SCM_RIGHTS; 82 cmsg->cmsg_len = CMSG_LEN(sizeof(fd)); 83 bcopy(&fd, CMSG_DATA(cmsg), sizeof(fd)); 84 85 if (sendmsg(sock, &msg, 0) == -1) 86 return (errno); 87 88 return (0); 89 } 90 91 int 92 proto_common_send(int sock, const unsigned char *data, size_t size, int fd) 93 { 94 ssize_t done; 95 size_t sendsize; 96 int errcount = 0; 97 98 PJDLOG_ASSERT(sock >= 0); 99 100 if (data == NULL) { 101 /* The caller is just trying to decide about direction. */ 102 103 PJDLOG_ASSERT(size == 0); 104 105 if (shutdown(sock, SHUT_RD) == -1) 106 return (errno); 107 return (0); 108 } 109 110 PJDLOG_ASSERT(data != NULL); 111 PJDLOG_ASSERT(size > 0); 112 113 do { 114 sendsize = size < MAX_SEND_SIZE ? size : MAX_SEND_SIZE; 115 done = send(sock, data, sendsize, MSG_NOSIGNAL); 116 if (done == 0) { 117 return (ENOTCONN); 118 } else if (done == -1) { 119 if (errno == EINTR) 120 continue; 121 if (errno == ENOBUFS) { 122 /* 123 * If there are no buffers we retry. 124 * After each try we increase delay before the 125 * next one and we give up after fifteen times. 126 * This gives 11s of total wait time. 127 */ 128 if (errcount == 15) { 129 pjdlog_warning("Getting ENOBUFS errors for 11s on send(), giving up."); 130 } else { 131 if (errcount == 0) 132 pjdlog_warning("Got ENOBUFS error on send(), retrying for a bit."); 133 errcount++; 134 usleep(100000 * errcount); 135 continue; 136 } 137 } 138 /* 139 * If this is blocking socket and we got EAGAIN, this 140 * means the request timed out. Translate errno to 141 * ETIMEDOUT, to give administrator a hint to 142 * eventually increase timeout. 143 */ 144 if (errno == EAGAIN && blocking_socket(sock)) 145 errno = ETIMEDOUT; 146 return (errno); 147 } 148 data += done; 149 size -= done; 150 } while (size > 0); 151 if (errcount > 0) { 152 pjdlog_info("Data sent successfully after %d ENOBUFS error%s.", 153 errcount, errcount == 1 ? "" : "s"); 154 } 155 156 if (fd == -1) 157 return (0); 158 return (proto_descriptor_send(sock, fd)); 159 } 160 161 static int 162 proto_descriptor_recv(int sock, int *fdp) 163 { 164 unsigned char ctrl[CMSG_SPACE(sizeof(*fdp))]; 165 struct msghdr msg; 166 struct cmsghdr *cmsg; 167 168 PJDLOG_ASSERT(sock >= 0); 169 PJDLOG_ASSERT(fdp != NULL); 170 171 bzero(&msg, sizeof(msg)); 172 bzero(&ctrl, sizeof(ctrl)); 173 174 msg.msg_iov = NULL; 175 msg.msg_iovlen = 0; 176 msg.msg_control = ctrl; 177 msg.msg_controllen = sizeof(ctrl); 178 179 if (recvmsg(sock, &msg, 0) == -1) 180 return (errno); 181 182 cmsg = CMSG_FIRSTHDR(&msg); 183 if (cmsg == NULL || cmsg->cmsg_level != SOL_SOCKET || 184 cmsg->cmsg_type != SCM_RIGHTS) { 185 return (EINVAL); 186 } 187 bcopy(CMSG_DATA(cmsg), fdp, sizeof(*fdp)); 188 189 return (0); 190 } 191 192 int 193 proto_common_recv(int sock, unsigned char *data, size_t size, int *fdp) 194 { 195 ssize_t done; 196 197 PJDLOG_ASSERT(sock >= 0); 198 199 if (data == NULL) { 200 /* The caller is just trying to decide about direction. */ 201 202 PJDLOG_ASSERT(size == 0); 203 204 if (shutdown(sock, SHUT_WR) == -1) 205 return (errno); 206 return (0); 207 } 208 209 PJDLOG_ASSERT(data != NULL); 210 PJDLOG_ASSERT(size > 0); 211 212 do { 213 done = recv(sock, data, size, MSG_WAITALL); 214 } while (done == -1 && errno == EINTR); 215 if (done == 0) { 216 return (ENOTCONN); 217 } else if (done == -1) { 218 /* 219 * If this is blocking socket and we got EAGAIN, this 220 * means the request timed out. Translate errno to 221 * ETIMEDOUT, to give administrator a hint to 222 * eventually increase timeout. 223 */ 224 if (errno == EAGAIN && blocking_socket(sock)) 225 errno = ETIMEDOUT; 226 return (errno); 227 } 228 if (fdp == NULL) 229 return (0); 230 return (proto_descriptor_recv(sock, fdp)); 231 } 232