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 31 static int control_fd = -1; 32 33 /* Open the control socket, either in server or client mode */ 34 void control_init(const char *control_host, 35 const char *control_port, 36 bool server) 37 { 38 struct addrinfo hints = { 39 .ai_socktype = SOCK_STREAM, 40 }; 41 struct addrinfo *result = NULL; 42 struct addrinfo *ai; 43 int ret; 44 45 ret = getaddrinfo(control_host, control_port, &hints, &result); 46 if (ret != 0) { 47 fprintf(stderr, "%s\n", gai_strerror(ret)); 48 exit(EXIT_FAILURE); 49 } 50 51 for (ai = result; ai; ai = ai->ai_next) { 52 int fd; 53 int val = 1; 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 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, 69 &val, sizeof(val)) < 0) { 70 perror("setsockopt"); 71 exit(EXIT_FAILURE); 72 } 73 74 if (bind(fd, ai->ai_addr, ai->ai_addrlen) < 0) 75 goto next; 76 if (listen(fd, 1) < 0) 77 goto next; 78 79 printf("Control socket listening on %s:%s\n", 80 control_host, control_port); 81 fflush(stdout); 82 83 control_fd = accept(fd, NULL, 0); 84 close(fd); 85 86 if (control_fd < 0) { 87 perror("accept"); 88 exit(EXIT_FAILURE); 89 } 90 printf("Control socket connection accepted...\n"); 91 break; 92 93 next: 94 close(fd); 95 } 96 97 if (control_fd < 0) { 98 fprintf(stderr, "Control socket initialization failed. Invalid address %s:%s?\n", 99 control_host, control_port); 100 exit(EXIT_FAILURE); 101 } 102 103 freeaddrinfo(result); 104 } 105 106 /* Free resources */ 107 void control_cleanup(void) 108 { 109 close(control_fd); 110 control_fd = -1; 111 } 112 113 /* Write a line to the control socket */ 114 void control_writeln(const char *str) 115 { 116 ssize_t len = strlen(str); 117 ssize_t ret; 118 119 timeout_begin(TIMEOUT); 120 121 do { 122 ret = send(control_fd, str, len, MSG_MORE); 123 timeout_check("send"); 124 } while (ret < 0 && errno == EINTR); 125 126 if (ret != len) { 127 perror("send"); 128 exit(EXIT_FAILURE); 129 } 130 131 do { 132 ret = send(control_fd, "\n", 1, 0); 133 timeout_check("send"); 134 } while (ret < 0 && errno == EINTR); 135 136 if (ret != 1) { 137 perror("send"); 138 exit(EXIT_FAILURE); 139 } 140 141 timeout_end(); 142 } 143 144 void control_writeulong(unsigned long value) 145 { 146 char str[32]; 147 148 if (snprintf(str, sizeof(str), "%lu", value) >= sizeof(str)) { 149 perror("snprintf"); 150 exit(EXIT_FAILURE); 151 } 152 153 control_writeln(str); 154 } 155 156 unsigned long control_readulong(void) 157 { 158 unsigned long value; 159 char *str; 160 161 str = control_readln(); 162 163 if (!str) 164 exit(EXIT_FAILURE); 165 166 value = strtoul(str, NULL, 10); 167 free(str); 168 169 return value; 170 } 171 172 /* Return the next line from the control socket (without the trailing newline). 173 * 174 * The program terminates if a timeout occurs. 175 * 176 * The caller must free() the returned string. 177 */ 178 char *control_readln(void) 179 { 180 char *buf = NULL; 181 size_t idx = 0; 182 size_t buflen = 0; 183 184 timeout_begin(TIMEOUT); 185 186 for (;;) { 187 ssize_t ret; 188 189 if (idx >= buflen) { 190 char *new_buf; 191 192 new_buf = realloc(buf, buflen + 80); 193 if (!new_buf) { 194 perror("realloc"); 195 exit(EXIT_FAILURE); 196 } 197 198 buf = new_buf; 199 buflen += 80; 200 } 201 202 do { 203 ret = recv(control_fd, &buf[idx], 1, 0); 204 timeout_check("recv"); 205 } while (ret < 0 && errno == EINTR); 206 207 if (ret == 0) { 208 fprintf(stderr, "unexpected EOF on control socket\n"); 209 exit(EXIT_FAILURE); 210 } 211 212 if (ret != 1) { 213 perror("recv"); 214 exit(EXIT_FAILURE); 215 } 216 217 if (buf[idx] == '\n') { 218 buf[idx] = '\0'; 219 break; 220 } 221 222 idx++; 223 } 224 225 timeout_end(); 226 227 return buf; 228 } 229 230 /* Wait until a given line is received or a timeout occurs */ 231 void control_expectln(const char *str) 232 { 233 char *line; 234 235 line = control_readln(); 236 237 control_cmpln(line, str, true); 238 239 free(line); 240 } 241 242 bool control_cmpln(char *line, const char *str, bool fail) 243 { 244 if (strcmp(str, line) == 0) 245 return true; 246 247 if (fail) { 248 fprintf(stderr, "expected \"%s\" on control socket, got \"%s\"\n", 249 str, line); 250 exit(EXIT_FAILURE); 251 } 252 253 return false; 254 } 255