contrib/ivshmem-server/main.c

   1 /*
   2  * Copyright 6WIND S.A., 2014
   3  *
   4  * This work is licensed under the terms of the GNU GPL, version 2 or
   5  * (at your option) any later version.  See the COPYING file in the
   6  * top-level directory.
   7  */
   8
   9 #include "qemu/osdep.h"
  10 #include "qapi/error.h"
  11 #include "qemu/cutils.h"
  12
  13 #include "ivshmem-server.h"
  14
  15 #define IVSHMEM_SERVER_DEFAULT_VERBOSE        0
  16 #define IVSHMEM_SERVER_DEFAULT_FOREGROUND     0
  17 #define IVSHMEM_SERVER_DEFAULT_PID_FILE       "/var/run/ivshmem-server.pid"
  18 #define IVSHMEM_SERVER_DEFAULT_UNIX_SOCK_PATH "/tmp/ivshmem_socket"
  19 #define IVSHMEM_SERVER_DEFAULT_SHM_PATH       "ivshmem"
  20 #define IVSHMEM_SERVER_DEFAULT_SHM_SIZE       (4*1024*1024)
  21 #define IVSHMEM_SERVER_DEFAULT_N_VECTORS      1
  22
  23 /* used to quit on signal SIGTERM */
  24 static int ivshmem_server_quit;
  25
  26 /* arguments given by the user */
  27 typedef struct IvshmemServerArgs {
  28     bool verbose;
  29     bool foreground;
  30     const char *pid_file;
  31     const char *unix_socket_path;
  32     const char *shm_path;
  33     bool use_shm_open;
  34     uint64_t shm_size;
  35     unsigned n_vectors;
  36 } IvshmemServerArgs;
  37
  38 static void
  39 ivshmem_server_usage(const char *progname)
  40 {
  41     printf("Usage: %s [OPTION]...\n"
  42            "  -h: show this help\n"
  43            "  -v: verbose mode\n"
  44            "  -F: foreground mode (default is to daemonize)\n"
  45            "  -p <pid-file>: path to the PID file (used in daemon mode only)\n"
  46            "     default " IVSHMEM_SERVER_DEFAULT_PID_FILE "\n"
  47            "  -S <unix-socket-path>: path to the unix socket to listen to\n"
  48            "     default " IVSHMEM_SERVER_DEFAULT_UNIX_SOCK_PATH "\n"
  49            "  -M <shm-name>: POSIX shared memory object to use\n"
  50            "     default " IVSHMEM_SERVER_DEFAULT_SHM_PATH "\n"
  51            "  -m <dir-name>: where to create shared memory\n"
  52            "  -l <size>: size of shared memory in bytes\n"
  53            "     suffixes K, M and G can be used, e.g. 1K means 1024\n"
  54            "     default %u\n"
  55            "  -n <nvectors>: number of vectors\n"
  56            "     default %u\n",
  57            progname, IVSHMEM_SERVER_DEFAULT_SHM_SIZE,
  58            IVSHMEM_SERVER_DEFAULT_N_VECTORS);
  59 }
  60
  61 static void
  62 ivshmem_server_help(const char *progname)
  63 {
  64     fprintf(stderr, "Try '%s -h' for more information.\n", progname);
  65 }
  66
  67 /* parse the program arguments, exit on error */
  68 static void
  69 ivshmem_server_parse_args(IvshmemServerArgs *args, int argc, char *argv[])
  70 {
  71     int c;
  72     unsigned long long v;
  73     Error *err = NULL;
  74
  75     while ((c = getopt(argc, argv, "hvFp:S:m:M:l:n:")) != -1) {
  76
  77         switch (c) {
  78         case 'h': /* help */
  79             ivshmem_server_usage(argv[0]);
  80             exit(0);
  81             break;
  82
  83         case 'v': /* verbose */
  84             args->verbose = 1;
  85             break;
  86
  87         case 'F': /* foreground */
  88             args->foreground = 1;
  89             break;
  90
  91         case 'p': /* pid file */
  92             args->pid_file = optarg;
  93             break;
  94
  95         case 'S': /* unix socket path */
  96             args->unix_socket_path = optarg;
  97             break;
  98
  99         case 'M': /* shm name */
 100         case 'm': /* dir name */
 101             args->shm_path = optarg;
 102             args->use_shm_open = c == 'M';
 103             break;
 104
 105         case 'l': /* shm size */
 106             parse_option_size("shm_size", optarg, &args->shm_size, &err);
 107             if (err) {
 108                 error_report_err(err);
 109                 ivshmem_server_help(argv[0]);
 110                 exit(1);
 111             }
 112             break;
 113
 114         case 'n': /* number of vectors */
 115             if (parse_uint_full(optarg, &v, 0) < 0) {
 116                 fprintf(stderr, "cannot parse n_vectors\n");
 117                 ivshmem_server_help(argv[0]);
 118                 exit(1);
 119             }
 120             args->n_vectors = v;
 121             break;
 122
 123         default:
 124             ivshmem_server_usage(argv[0]);
 125             exit(1);
 126             break;
 127         }
 128     }
 129
 130     if (args->n_vectors > IVSHMEM_SERVER_MAX_VECTORS) {
 131         fprintf(stderr, "too many requested vectors (max is %d)\n",
 132                 IVSHMEM_SERVER_MAX_VECTORS);
 133         ivshmem_server_help(argv[0]);
 134         exit(1);
 135     }
 136
 137     if (args->verbose == 1 && args->foreground == 0) {
 138         fprintf(stderr, "cannot use verbose in daemon mode\n");
 139         ivshmem_server_help(argv[0]);
 140         exit(1);
 141     }
 142 }
 143
 144 /* wait for events on listening server unix socket and connected client
 145  * sockets */
 146 static int
 147 ivshmem_server_poll_events(IvshmemServer *server)
 148 {
 149     fd_set fds;
 150     int ret = 0, maxfd;
 151
 152     while (!ivshmem_server_quit) {
 153
 154         FD_ZERO(&fds);
 155         maxfd = 0;
 156         ivshmem_server_get_fds(server, &fds, &maxfd);
 157
 158         ret = select(maxfd, &fds, NULL, NULL, NULL);
 159
 160         if (ret < 0) {
 161             if (errno == EINTR) {
 162                 continue;
 163             }
 164
 165             fprintf(stderr, "select error: %s\n", strerror(errno));
 166             break;
 167         }
 168         if (ret == 0) {
 169             continue;
 170         }
 171
 172         if (ivshmem_server_handle_fds(server, &fds, maxfd) < 0) {
 173             fprintf(stderr, "ivshmem_server_handle_fds() failed\n");
 174             break;
 175         }
 176     }
 177
 178     return ret;
 179 }
 180
 181 static void
 182 ivshmem_server_quit_cb(int signum)
 183 {
 184     ivshmem_server_quit = 1;
 185 }
 186
 187 int
 188 main(int argc, char *argv[])
 189 {
 190     IvshmemServer server;
 191     struct sigaction sa, sa_quit;
 192     IvshmemServerArgs args = {
 193         .verbose = IVSHMEM_SERVER_DEFAULT_VERBOSE,
 194         .foreground = IVSHMEM_SERVER_DEFAULT_FOREGROUND,
 195         .pid_file = IVSHMEM_SERVER_DEFAULT_PID_FILE,
 196         .unix_socket_path = IVSHMEM_SERVER_DEFAULT_UNIX_SOCK_PATH,
 197         .shm_path = IVSHMEM_SERVER_DEFAULT_SHM_PATH,
 198         .use_shm_open = true,
 199         .shm_size = IVSHMEM_SERVER_DEFAULT_SHM_SIZE,
 200         .n_vectors = IVSHMEM_SERVER_DEFAULT_N_VECTORS,
 201     };
 202     int ret = 1;
 203
 204     /*
 205      * Do not remove this notice without adding proper error handling!
 206      * Start with handling ivshmem_server_send_one_msg() failure.
 207      */
 208     printf("*** Example code, do not use in production ***\n");
 209
 210     /* parse arguments, will exit on error */
 211     ivshmem_server_parse_args(&args, argc, argv);
 212
 213     /* Ignore SIGPIPE, see this link for more info:
 214      * http://www.mail-archive.com/libevent-users@monkey.org/msg01606.html */
 215     sa.sa_handler = SIG_IGN;
 216     sa.sa_flags = 0;
 217     if (sigemptyset(&sa.sa_mask) == -1 ||
 218         sigaction(SIGPIPE, &sa, 0) == -1) {
 219         perror("failed to ignore SIGPIPE; sigaction");
 220         goto err;
 221     }
 222
 223     sa_quit.sa_handler = ivshmem_server_quit_cb;
 224     sa_quit.sa_flags = 0;
 225     if (sigemptyset(&sa_quit.sa_mask) == -1 ||
 226         sigaction(SIGTERM, &sa_quit, 0) == -1) {
 227         perror("failed to add SIGTERM handler; sigaction");
 228         goto err;
 229     }
 230
 231     /* init the ivshms structure */
 232     if (ivshmem_server_init(&server, args.unix_socket_path,
 233                             args.shm_path, args.use_shm_open,
 234                             args.shm_size, args.n_vectors, args.verbose) < 0) {
 235         fprintf(stderr, "cannot init server\n");
 236         goto err;
 237     }
 238
 239     /* start the ivshmem server (open shm & unix socket) */
 240     if (ivshmem_server_start(&server) < 0) {
 241         fprintf(stderr, "cannot bind\n");
 242         goto err;
 243     }
 244
 245     /* daemonize if asked to */
 246     if (!args.foreground) {
 247         FILE *fp;
 248
 249         if (qemu_daemon(1, 1) < 0) {
 250             fprintf(stderr, "cannot daemonize: %s\n", strerror(errno));
 251             goto err_close;
 252         }
 253
 254         /* write pid file */
 255         fp = fopen(args.pid_file, "w");
 256         if (fp == NULL) {
 257             fprintf(stderr, "cannot write pid file: %s\n", strerror(errno));
 258             goto err_close;
 259         }
 260
 261         fprintf(fp, "%d\n", (int) getpid());
 262         fclose(fp);
 263     }
 264
 265     ivshmem_server_poll_events(&server);
 266     fprintf(stdout, "server disconnected\n");
 267     ret = 0;
 268
 269 err_close:
 270     ivshmem_server_close(&server);
 271 err:
 272     return ret;
 273 }