tools/testing/vsock/control.c

   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 /* Return the next line from the control socket (without the trailing newline).
 145  *
 146  * The program terminates if a timeout occurs.
 147  *
 148  * The caller must free() the returned string.
 149  */
 150 char *control_readln(void)
 151 {
 152         char *buf = NULL;
 153         size_t idx = 0;
 154         size_t buflen = 0;
 155
 156         timeout_begin(TIMEOUT);
 157
 158         for (;;) {
 159                 ssize_t ret;
 160
 161                 if (idx >= buflen) {
 162                         char *new_buf;
 163
 164                         new_buf = realloc(buf, buflen + 80);
 165                         if (!new_buf) {
 166                                 perror("realloc");
 167                                 exit(EXIT_FAILURE);
 168                         }
 169
 170                         buf = new_buf;
 171                         buflen += 80;
 172                 }
 173
 174                 do {
 175                         ret = recv(control_fd, &buf[idx], 1, 0);
 176                         timeout_check("recv");
 177                 } while (ret < 0 && errno == EINTR);
 178
 179                 if (ret == 0) {
 180                         fprintf(stderr, "unexpected EOF on control socket\n");
 181                         exit(EXIT_FAILURE);
 182                 }
 183
 184                 if (ret != 1) {
 185                         perror("recv");
 186                         exit(EXIT_FAILURE);
 187                 }
 188
 189                 if (buf[idx] == '\n') {
 190                         buf[idx] = '\0';
 191                         break;
 192                 }
 193
 194                 idx++;
 195         }
 196
 197         timeout_end();
 198
 199         return buf;
 200 }
 201
 202 /* Wait until a given line is received or a timeout occurs */
 203 void control_expectln(const char *str)
 204 {
 205         char *line;
 206
 207         line = control_readln();
 208         if (strcmp(str, line) != 0) {
 209                 fprintf(stderr, "expected \"%s\" on control socket, got \"%s\"\n",
 210                         str, line);
 211                 exit(EXIT_FAILURE);
 212         }
 213
 214         free(line);
 215 }