1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Control socket for client/server test execution 3 * 4 * Copyright (C) 2017 Red Hat, Inc. 5 * 6 * Author: Stefan Hajnoczi <stefanha@redhat.com> 7 */ 8 9 /* The client and server may need to coordinate to avoid race conditions like 10 * the client attempting to connect to a socket that the server is not 11 * listening on yet. The control socket offers a communications channel for 12 * such coordination tasks. 13 * 14 * If the client calls control_expectln("LISTENING"), then it will block until 15 * the server calls control_writeln("LISTENING"). This provides a simple 16 * mechanism for coordinating between the client and the server. 17 */ 18 19 #include <errno.h> 20 #include <netdb.h> 21 #include <stdio.h> 22 #include <stdlib.h> 23 #include <string.h> 24 #include <unistd.h> 25 #include <sys/types.h> 26 #include <sys/socket.h> 27 28 #include "timeout.h" 29 #include "control.h" 30 #include "util.h" 31 32 static int control_fd = -1; 33 34 /* Open the control socket, either in server or client mode */ 35 void control_init(const char *control_host, 36 const char *control_port, 37 bool server) 38 { 39 struct addrinfo hints = { 40 .ai_socktype = SOCK_STREAM, 41 }; 42 struct addrinfo *result = NULL; 43 struct addrinfo *ai; 44 int ret; 45 46 ret = getaddrinfo(control_host, control_port, &hints, &result); 47 if (ret != 0) { 48 fprintf(stderr, "%s\n", gai_strerror(ret)); 49 exit(EXIT_FAILURE); 50 } 51 52 for (ai = result; ai; ai = ai->ai_next) { 53 int fd; 54 55 fd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 56 if (fd < 0) 57 continue; 58 59 if (!server) { 60 if (connect(fd, ai->ai_addr, ai->ai_addrlen) < 0) 61 goto next; 62 control_fd = fd; 63 printf("Control socket connected to %s:%s.\n", 64 control_host, control_port); 65 break; 66 } 67 68 setsockopt_int_check(fd, SOL_SOCKET, SO_REUSEADDR, 1, 69 "setsockopt SO_REUSEADDR"); 70 71 if (bind(fd, ai->ai_addr, ai->ai_addrlen) < 0) 72 goto next; 73 if (listen(fd, 1) < 0) 74 goto next; 75 76 printf("Control socket listening on %s:%s\n", 77 control_host, control_port); 78 fflush(stdout); 79 80 control_fd = accept(fd, NULL, 0); 81 close(fd); 82 83 if (control_fd < 0) { 84 perror("accept"); 85 exit(EXIT_FAILURE); 86 } 87 printf("Control socket connection accepted...\n"); 88 break; 89 90 next: 91 close(fd); 92 } 93 94 if (control_fd < 0) { 95 fprintf(stderr, "Control socket initialization failed. Invalid address %s:%s?\n", 96 control_host, control_port); 97 exit(EXIT_FAILURE); 98 } 99 100 freeaddrinfo(result); 101 } 102 103 /* Free resources */ 104 void control_cleanup(void) 105 { 106 close(control_fd); 107 control_fd = -1; 108 } 109 110 /* Write a line to the control socket */ 111 void control_writeln(const char *str) 112 { 113 ssize_t len = strlen(str); 114 ssize_t ret; 115 116 timeout_begin(TIMEOUT); 117 118 do { 119 ret = send(control_fd, str, len, MSG_MORE); 120 timeout_check("send"); 121 } while (ret < 0 && errno == EINTR); 122 123 if (ret != len) { 124 perror("send"); 125 exit(EXIT_FAILURE); 126 } 127 128 do { 129 ret = send(control_fd, "\n", 1, 0); 130 timeout_check("send"); 131 } while (ret < 0 && errno == EINTR); 132 133 if (ret != 1) { 134 perror("send"); 135 exit(EXIT_FAILURE); 136 } 137 138 timeout_end(); 139 } 140 141 void control_writeulong(unsigned long value) 142 { 143 char str[32]; 144 145 if (snprintf(str, sizeof(str), "%lu", value) >= sizeof(str)) { 146 perror("snprintf"); 147 exit(EXIT_FAILURE); 148 } 149 150 control_writeln(str); 151 } 152 153 unsigned long control_readulong(void) 154 { 155 unsigned long value; 156 char *str; 157 158 str = control_readln(); 159 160 if (!str) 161 exit(EXIT_FAILURE); 162 163 value = strtoul(str, NULL, 10); 164 free(str); 165 166 return value; 167 } 168 169 /* Return the next line from the control socket (without the trailing newline). 170 * 171 * The program terminates if a timeout occurs. 172 * 173 * The caller must free() the returned string. 174 */ 175 char *control_readln(void) 176 { 177 char *buf = NULL; 178 size_t idx = 0; 179 size_t buflen = 0; 180 181 timeout_begin(TIMEOUT); 182 183 for (;;) { 184 ssize_t ret; 185 186 if (idx >= buflen) { 187 char *new_buf; 188 189 new_buf = realloc(buf, buflen + 80); 190 if (!new_buf) { 191 perror("realloc"); 192 exit(EXIT_FAILURE); 193 } 194 195 buf = new_buf; 196 buflen += 80; 197 } 198 199 do { 200 ret = recv(control_fd, &buf[idx], 1, 0); 201 timeout_check("recv"); 202 } while (ret < 0 && errno == EINTR); 203 204 if (ret == 0) { 205 fprintf(stderr, "unexpected EOF on control socket\n"); 206 exit(EXIT_FAILURE); 207 } 208 209 if (ret != 1) { 210 perror("recv"); 211 exit(EXIT_FAILURE); 212 } 213 214 if (buf[idx] == '\n') { 215 buf[idx] = '\0'; 216 break; 217 } 218 219 idx++; 220 } 221 222 timeout_end(); 223 224 return buf; 225 } 226 227 /* Wait until a given line is received or a timeout occurs */ 228 void control_expectln(const char *str) 229 { 230 char *line; 231 232 line = control_readln(); 233 234 control_cmpln(line, str, true); 235 236 free(line); 237 } 238 239 bool control_cmpln(char *line, const char *str, bool fail) 240 { 241 if (strcmp(str, line) == 0) 242 return true; 243 244 if (fail) { 245 fprintf(stderr, "expected \"%s\" on control socket, got \"%s\"\n", 246 str, line); 247 exit(EXIT_FAILURE); 248 } 249 250 return false; 251 } 252