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 * $P4: //depot/projects/trustedbsd/openbsm/bin/auditdistd/proto_common.c#1 $ 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 <compat/compat.h> 44 45 #include "pjdlog.h" 46 #include "proto_impl.h" 47 48 /* Maximum size of packet we want to use when sending data. */ 49 #ifndef MAX_SEND_SIZE 50 #define MAX_SEND_SIZE 32768 51 #endif 52 53 static bool 54 blocking_socket(int sock) 55 { 56 int flags; 57 58 flags = fcntl(sock, F_GETFL); 59 PJDLOG_ASSERT(flags >= 0); 60 return ((flags & O_NONBLOCK) == 0); 61 } 62 63 static int 64 proto_descriptor_send(int sock, int fd) 65 { 66 unsigned char ctrl[CMSG_SPACE(sizeof(fd))]; 67 struct msghdr msg; 68 struct cmsghdr *cmsg; 69 70 PJDLOG_ASSERT(sock >= 0); 71 PJDLOG_ASSERT(fd >= 0); 72 73 bzero(&msg, sizeof(msg)); 74 bzero(&ctrl, sizeof(ctrl)); 75 76 msg.msg_iov = NULL; 77 msg.msg_iovlen = 0; 78 msg.msg_control = ctrl; 79 msg.msg_controllen = sizeof(ctrl); 80 81 cmsg = CMSG_FIRSTHDR(&msg); 82 cmsg->cmsg_level = SOL_SOCKET; 83 cmsg->cmsg_type = SCM_RIGHTS; 84 cmsg->cmsg_len = CMSG_LEN(sizeof(fd)); 85 bcopy(&fd, CMSG_DATA(cmsg), sizeof(fd)); 86 87 if (sendmsg(sock, &msg, 0) == -1) 88 return (errno); 89 90 return (0); 91 } 92 93 int 94 proto_common_send(int sock, const unsigned char *data, size_t size, int fd) 95 { 96 ssize_t done; 97 size_t sendsize; 98 int errcount = 0; 99 100 PJDLOG_ASSERT(sock >= 0); 101 102 if (data == NULL) { 103 /* The caller is just trying to decide about direction. */ 104 105 PJDLOG_ASSERT(size == 0); 106 107 if (shutdown(sock, SHUT_RD) == -1) 108 return (errno); 109 return (0); 110 } 111 112 PJDLOG_ASSERT(data != NULL); 113 PJDLOG_ASSERT(size > 0); 114 115 do { 116 sendsize = size < MAX_SEND_SIZE ? size : MAX_SEND_SIZE; 117 done = send(sock, data, sendsize, MSG_NOSIGNAL); 118 if (done == 0) { 119 return (ENOTCONN); 120 } else if (done < 0) { 121 if (errno == EINTR) 122 continue; 123 if (errno == ENOBUFS) { 124 /* 125 * If there are no buffers we retry. 126 * After each try we increase delay before the 127 * next one and we give up after fifteen times. 128 * This gives 11s of total wait time. 129 */ 130 if (errcount == 15) { 131 pjdlog_warning("Getting ENOBUFS errors for 11s on send(), giving up."); 132 } else { 133 if (errcount == 0) 134 pjdlog_warning("Got ENOBUFS error on send(), retrying for a bit."); 135 errcount++; 136 usleep(100000 * errcount); 137 continue; 138 } 139 } 140 /* 141 * If this is blocking socket and we got EAGAIN, this 142 * means the request timed out. Translate errno to 143 * ETIMEDOUT, to give administrator a hint to 144 * eventually increase timeout. 145 */ 146 if (errno == EAGAIN && blocking_socket(sock)) 147 errno = ETIMEDOUT; 148 return (errno); 149 } 150 data += done; 151 size -= done; 152 } while (size > 0); 153 if (errcount > 0) { 154 pjdlog_info("Data sent successfully after %d ENOBUFS error%s.", 155 errcount, errcount == 1 ? "" : "s"); 156 } 157 158 if (fd == -1) 159 return (0); 160 return (proto_descriptor_send(sock, fd)); 161 } 162 163 static int 164 proto_descriptor_recv(int sock, int *fdp) 165 { 166 unsigned char ctrl[CMSG_SPACE(sizeof(*fdp))]; 167 struct msghdr msg; 168 struct cmsghdr *cmsg; 169 170 PJDLOG_ASSERT(sock >= 0); 171 PJDLOG_ASSERT(fdp != NULL); 172 173 bzero(&msg, sizeof(msg)); 174 bzero(&ctrl, sizeof(ctrl)); 175 176 msg.msg_iov = NULL; 177 msg.msg_iovlen = 0; 178 msg.msg_control = ctrl; 179 msg.msg_controllen = sizeof(ctrl); 180 181 if (recvmsg(sock, &msg, 0) == -1) 182 return (errno); 183 184 cmsg = CMSG_FIRSTHDR(&msg); 185 if (cmsg->cmsg_level != SOL_SOCKET || 186 cmsg->cmsg_type != SCM_RIGHTS) { 187 return (EINVAL); 188 } 189 bcopy(CMSG_DATA(cmsg), fdp, sizeof(*fdp)); 190 191 return (0); 192 } 193 194 int 195 proto_common_recv(int sock, unsigned char *data, size_t size, int *fdp) 196 { 197 ssize_t done; 198 199 PJDLOG_ASSERT(sock >= 0); 200 201 if (data == NULL) { 202 /* The caller is just trying to decide about direction. */ 203 204 PJDLOG_ASSERT(size == 0); 205 206 if (shutdown(sock, SHUT_WR) == -1) 207 return (errno); 208 return (0); 209 } 210 211 PJDLOG_ASSERT(data != NULL); 212 PJDLOG_ASSERT(size > 0); 213 214 do { 215 done = recv(sock, data, size, MSG_WAITALL); 216 } while (done == -1 && errno == EINTR); 217 if (done == 0) { 218 return (ENOTCONN); 219 } else if (done < 0) { 220 /* 221 * If this is blocking socket and we got EAGAIN, this 222 * means the request timed out. Translate errno to 223 * ETIMEDOUT, to give administrator a hint to 224 * eventually increase timeout. 225 */ 226 if (errno == EAGAIN && blocking_socket(sock)) 227 errno = ETIMEDOUT; 228 return (errno); 229 } 230 if (fdp == NULL) 231 return (0); 232 return (proto_descriptor_recv(sock, fdp)); 233 } 234