contrib: add ivshmem client and server

When using ivshmem devices, notifications between guests can be sent as
interrupts using a ivshmem-server (typical use described in documentation).
The client is provided as a debug tool.

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
Signed-off-by: David Marchand <david.marchand@6wind.com>
[fix a valgrind warning, option and server_close() segvs, extra server
headers includes, getopt() return type, out-of-tree build, use qemu
event_notifier instead of eventfd, fix x86/osx warnings - Marc-André]
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

1 files changed, 264 insertions, 0 deletions

diff --git a/contrib/ivshmem-server/main.c b/contrib/ivshmem-server/main.c
new file mode 100644
index 0000000..064de02
--- /dev/null
+++ b/contrib/ivshmem-server/main.c
@@ -0,0 +1,264 @@
+/*
+ * Copyright 6WIND S.A., 2014
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * (at your option) any later version.  See the COPYING file in the
+ * top-level directory.
+ */
+
+#include "qemu-common.h"
+
+#include "ivshmem-server.h"
+
+#define IVSHMEM_SERVER_DEFAULT_VERBOSE        0
+#define IVSHMEM_SERVER_DEFAULT_FOREGROUND     0
+#define IVSHMEM_SERVER_DEFAULT_PID_FILE       "/var/run/ivshmem-server.pid"
+#define IVSHMEM_SERVER_DEFAULT_UNIX_SOCK_PATH "/tmp/ivshmem_socket"
+#define IVSHMEM_SERVER_DEFAULT_SHM_PATH       "ivshmem"
+#define IVSHMEM_SERVER_DEFAULT_SHM_SIZE       (4*1024*1024)
+#define IVSHMEM_SERVER_DEFAULT_N_VECTORS      1
+
+/* used to quit on signal SIGTERM */
+static int ivshmem_server_quit;
+
+/* arguments given by the user */
+typedef struct IvshmemServerArgs {
+    bool verbose;
+    bool foreground;
+    const char *pid_file;
+    const char *unix_socket_path;
+    const char *shm_path;
+    uint64_t shm_size;
+    unsigned n_vectors;
+} IvshmemServerArgs;
+
+/* show ivshmem_server_usage and exit with given error code */
+static void
+ivshmem_server_usage(const char *name, int code)
+{
+    fprintf(stderr, "%s [opts]\n", name);
+    fprintf(stderr, "  -h: show this help\n");
+    fprintf(stderr, "  -v: verbose mode\n");
+    fprintf(stderr, "  -F: foreground mode (default is to daemonize)\n");
+    fprintf(stderr, "  -p <pid_file>: path to the PID file (used in daemon\n"
+                    "     mode only).\n"
+                    "     Default=%s\n", IVSHMEM_SERVER_DEFAULT_SHM_PATH);
+    fprintf(stderr, "  -S <unix_socket_path>: path to the unix socket\n"
+                    "     to listen to.\n"
+                    "     Default=%s\n", IVSHMEM_SERVER_DEFAULT_UNIX_SOCK_PATH);
+    fprintf(stderr, "  -m <shm_path>: path to the shared memory.\n"
+                    "     The path corresponds to a POSIX shm name. To use a\n"
+                    "     real file, for instance in a hugetlbfs, use\n"
+                    "     /../../abspath/to/file.\n"
+                    "     default=%s\n", IVSHMEM_SERVER_DEFAULT_SHM_PATH);
+    fprintf(stderr, "  -l <size>: size of shared memory in bytes. The suffix\n"
+                    "     K, M and G can be used (ex: 1K means 1024).\n"
+                    "     default=%u\n", IVSHMEM_SERVER_DEFAULT_SHM_SIZE);
+    fprintf(stderr, "  -n <n_vects>: number of vectors.\n"
+                    "     default=%u\n", IVSHMEM_SERVER_DEFAULT_N_VECTORS);
+
+    exit(code);
+}
+
+/* parse the program arguments, exit on error */
+static void
+ivshmem_server_parse_args(IvshmemServerArgs *args, int argc, char *argv[])
+{
+    int c;
+    unsigned long long v;
+    Error *errp = NULL;
+
+    while ((c = getopt(argc, argv,
+                       "h"  /* help */
+                       "v"  /* verbose */
+                       "F"  /* foreground */
+                       "p:" /* pid_file */
+                       "S:" /* unix_socket_path */
+                       "m:" /* shm_path */
+                       "l:" /* shm_size */
+                       "n:" /* n_vectors */
+                      )) != -1) {
+
+        switch (c) {
+        case 'h': /* help */
+            ivshmem_server_usage(argv[0], 0);
+            break;
+
+        case 'v': /* verbose */
+            args->verbose = 1;
+            break;
+
+        case 'F': /* foreground */
+            args->foreground = 1;
+            break;
+
+        case 'p': /* pid_file */
+            args->pid_file = strdup(optarg);
+            break;
+
+        case 'S': /* unix_socket_path */
+            args->unix_socket_path = strdup(optarg);
+            break;
+
+        case 'm': /* shm_path */
+            args->shm_path = strdup(optarg);
+            break;
+
+        case 'l': /* shm_size */
+            parse_option_size("shm_size", optarg, &args->shm_size, &errp);
+            if (errp) {
+                fprintf(stderr, "cannot parse shm size: %s\n",
+                        error_get_pretty(errp));
+                error_free(errp);
+                ivshmem_server_usage(argv[0], 1);
+            }
+            break;
+
+        case 'n': /* n_vectors */
+            if (parse_uint_full(optarg, &v, 0) < 0) {
+                fprintf(stderr, "cannot parse n_vectors\n");
+                ivshmem_server_usage(argv[0], 1);
+            }
+            args->n_vectors = v;
+            break;
+
+        default:
+            ivshmem_server_usage(argv[0], 1);
+            break;
+        }
+    }
+
+    if (args->n_vectors > IVSHMEM_SERVER_MAX_VECTORS) {
+        fprintf(stderr, "too many requested vectors (max is %d)\n",
+                IVSHMEM_SERVER_MAX_VECTORS);
+        ivshmem_server_usage(argv[0], 1);
+    }
+
+    if (args->verbose == 1 && args->foreground == 0) {
+        fprintf(stderr, "cannot use verbose in daemon mode\n");
+        ivshmem_server_usage(argv[0], 1);
+    }
+}
+
+/* wait for events on listening server unix socket and connected client
+ * sockets */
+static int
+ivshmem_server_poll_events(IvshmemServer *server)
+{
+    fd_set fds;
+    int ret = 0, maxfd;
+
+    while (!ivshmem_server_quit) {
+
+        FD_ZERO(&fds);
+        maxfd = 0;
+        ivshmem_server_get_fds(server, &fds, &maxfd);
+
+        ret = select(maxfd, &fds, NULL, NULL, NULL);
+
+        if (ret < 0) {
+            if (errno == EINTR) {
+                continue;
+            }
+
+            fprintf(stderr, "select error: %s\n", strerror(errno));
+            break;
+        }
+        if (ret == 0) {
+            continue;
+        }
+
+        if (ivshmem_server_handle_fds(server, &fds, maxfd) < 0) {
+            fprintf(stderr, "ivshmem_server_handle_fds() failed\n");
+            break;
+        }
+    }
+
+    return ret;
+}
+
+static void
+ivshmem_server_quit_cb(int signum)
+{
+    ivshmem_server_quit = 1;
+}
+
+int
+main(int argc, char *argv[])
+{
+    IvshmemServer server;
+    struct sigaction sa, sa_quit;
+    IvshmemServerArgs args = {
+        .verbose = IVSHMEM_SERVER_DEFAULT_VERBOSE,
+        .foreground = IVSHMEM_SERVER_DEFAULT_FOREGROUND,
+        .pid_file = IVSHMEM_SERVER_DEFAULT_PID_FILE,
+        .unix_socket_path = IVSHMEM_SERVER_DEFAULT_UNIX_SOCK_PATH,
+        .shm_path = IVSHMEM_SERVER_DEFAULT_SHM_PATH,
+        .shm_size = IVSHMEM_SERVER_DEFAULT_SHM_SIZE,
+        .n_vectors = IVSHMEM_SERVER_DEFAULT_N_VECTORS,
+    };
+    int ret = 1;
+
+    /* parse arguments, will exit on error */
+    ivshmem_server_parse_args(&args, argc, argv);
+
+    /* Ignore SIGPIPE, see this link for more info:
+     * http://www.mail-archive.com/libevent-users@monkey.org/msg01606.html */
+    sa.sa_handler = SIG_IGN;
+    sa.sa_flags = 0;
+    if (sigemptyset(&sa.sa_mask) == -1 ||
+        sigaction(SIGPIPE, &sa, 0) == -1) {
+        perror("failed to ignore SIGPIPE; sigaction");
+        goto err;
+    }
+
+    sa_quit.sa_handler = ivshmem_server_quit_cb;
+    sa_quit.sa_flags = 0;
+    if (sigemptyset(&sa_quit.sa_mask) == -1 ||
+        sigaction(SIGTERM, &sa_quit, 0) == -1) {
+        perror("failed to add SIGTERM handler; sigaction");
+        goto err;
+    }
+
+    /* init the ivshms structure */
+    if (ivshmem_server_init(&server, args.unix_socket_path, args.shm_path,
+                            args.shm_size, args.n_vectors, args.verbose) < 0) {
+        fprintf(stderr, "cannot init server\n");
+        goto err;
+    }
+
+    /* start the ivshmem server (open shm & unix socket) */
+    if (ivshmem_server_start(&server) < 0) {
+        fprintf(stderr, "cannot bind\n");
+        goto err;
+    }
+
+    /* daemonize if asked to */
+    if (!args.foreground) {
+        FILE *fp;
+
+        if (qemu_daemon(1, 1) < 0) {
+            fprintf(stderr, "cannot daemonize: %s\n", strerror(errno));
+            goto err_close;
+        }
+
+        /* write pid file */
+        fp = fopen(args.pid_file, "w");
+        if (fp == NULL) {
+            fprintf(stderr, "cannot write pid file: %s\n", strerror(errno));
+            goto err_close;
+        }
+
+        fprintf(fp, "%d\n", (int) getpid());
+        fclose(fp);
+    }
+
+    ivshmem_server_poll_events(&server);
+    fprintf(stdout, "server disconnected\n");
+    ret = 0;
+
+err_close:
+    ivshmem_server_close(&server);
+err:
+    return ret;
+}