1 /* Control socket for client/server test execution 2 * 3 * Copyright (C) 2017 Red Hat, Inc. 4 * 5 * Author: Stefan Hajnoczi <stefanha@redhat.com> 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; version 2 10 * of the License. 11 */ 12 13 /* The client and server may need to coordinate to avoid race conditions like 14 * the client attempting to connect to a socket that the server is not 15 * listening on yet. The control socket offers a communications channel for 16 * such coordination tasks. 17 * 18 * If the client calls control_expectln("LISTENING"), then it will block until 19 * the server calls control_writeln("LISTENING"). This provides a simple 20 * mechanism for coordinating between the client and the server. 21 */ 22 23 #include <errno.h> 24 #include <netdb.h> 25 #include <stdio.h> 26 #include <stdlib.h> 27 #include <string.h> 28 #include <unistd.h> 29 #include <sys/types.h> 30 #include <sys/socket.h> 31 32 #include "timeout.h" 33 #include "control.h" 34 35 static int control_fd = -1; 36 37 /* Open the control socket, either in server or client mode */ 38 void control_init(const char *control_host, 39 const char *control_port, 40 bool server) 41 { 42 struct addrinfo hints = { 43 .ai_socktype = SOCK_STREAM, 44 }; 45 struct addrinfo *result = NULL; 46 struct addrinfo *ai; 47 int ret; 48 49 ret = getaddrinfo(control_host, control_port, &hints, &result); 50 if (ret != 0) { 51 fprintf(stderr, "%s\n", gai_strerror(ret)); 52 exit(EXIT_FAILURE); 53 } 54 55 for (ai = result; ai; ai = ai->ai_next) { 56 int fd; 57 int val = 1; 58 59 fd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 60 if (fd < 0) 61 continue; 62 63 if (!server) { 64 if (connect(fd, ai->ai_addr, ai->ai_addrlen) < 0) 65 goto next; 66 control_fd = fd; 67 printf("Control socket connected to %s:%s.\n", 68 control_host, control_port); 69 break; 70 } 71 72 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, 73 &val, sizeof(val)) < 0) { 74 perror("setsockopt"); 75 exit(EXIT_FAILURE); 76 } 77 78 if (bind(fd, ai->ai_addr, ai->ai_addrlen) < 0) 79 goto next; 80 if (listen(fd, 1) < 0) 81 goto next; 82 83 printf("Control socket listening on %s:%s\n", 84 control_host, control_port); 85 fflush(stdout); 86 87 control_fd = accept(fd, NULL, 0); 88 close(fd); 89 90 if (control_fd < 0) { 91 perror("accept"); 92 exit(EXIT_FAILURE); 93 } 94 printf("Control socket connection accepted...\n"); 95 break; 96 97 next: 98 close(fd); 99 } 100 101 if (control_fd < 0) { 102 fprintf(stderr, "Control socket initialization failed. Invalid address %s:%s?\n", 103 control_host, control_port); 104 exit(EXIT_FAILURE); 105 } 106 107 freeaddrinfo(result); 108 } 109 110 /* Free resources */ 111 void control_cleanup(void) 112 { 113 close(control_fd); 114 control_fd = -1; 115 } 116 117 /* Write a line to the control socket */ 118 void control_writeln(const char *str) 119 { 120 ssize_t len = strlen(str); 121 ssize_t ret; 122 123 timeout_begin(TIMEOUT); 124 125 do { 126 ret = send(control_fd, str, len, MSG_MORE); 127 timeout_check("send"); 128 } while (ret < 0 && errno == EINTR); 129 130 if (ret != len) { 131 perror("send"); 132 exit(EXIT_FAILURE); 133 } 134 135 do { 136 ret = send(control_fd, "\n", 1, 0); 137 timeout_check("send"); 138 } while (ret < 0 && errno == EINTR); 139 140 if (ret != 1) { 141 perror("send"); 142 exit(EXIT_FAILURE); 143 } 144 145 timeout_end(); 146 } 147 148 /* Return the next line from the control socket (without the trailing newline). 149 * 150 * The program terminates if a timeout occurs. 151 * 152 * The caller must free() the returned string. 153 */ 154 char *control_readln(void) 155 { 156 char *buf = NULL; 157 size_t idx = 0; 158 size_t buflen = 0; 159 160 timeout_begin(TIMEOUT); 161 162 for (;;) { 163 ssize_t ret; 164 165 if (idx >= buflen) { 166 char *new_buf; 167 168 new_buf = realloc(buf, buflen + 80); 169 if (!new_buf) { 170 perror("realloc"); 171 exit(EXIT_FAILURE); 172 } 173 174 buf = new_buf; 175 buflen += 80; 176 } 177 178 do { 179 ret = recv(control_fd, &buf[idx], 1, 0); 180 timeout_check("recv"); 181 } while (ret < 0 && errno == EINTR); 182 183 if (ret == 0) { 184 fprintf(stderr, "unexpected EOF on control socket\n"); 185 exit(EXIT_FAILURE); 186 } 187 188 if (ret != 1) { 189 perror("recv"); 190 exit(EXIT_FAILURE); 191 } 192 193 if (buf[idx] == '\n') { 194 buf[idx] = '\0'; 195 break; 196 } 197 198 idx++; 199 } 200 201 timeout_end(); 202 203 return buf; 204 } 205 206 /* Wait until a given line is received or a timeout occurs */ 207 void control_expectln(const char *str) 208 { 209 char *line; 210 211 line = control_readln(); 212 if (strcmp(str, line) != 0) { 213 fprintf(stderr, "expected \"%s\" on control socket, got \"%s\"\n", 214 str, line); 215 exit(EXIT_FAILURE); 216 } 217 218 free(line); 219 } 220