Re: [PATCH v5] Implement backend program convention command for vhost-user-blk

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Nov 19, 2019 at 02:39:11PM +0800, Micky Yun Chan wrote:
> From: michan <michan@redhat.com>
> 
> This patch is to add standard commands defined in docs/interop/vhost-user.rst
> For vhost-user-* program
> 
> Signed-off-by: Micky Yun Chan (michiboo) <chanmickyyun@gmail.com>


lots of comments by others already, just adding a minor nit:

> ---
>  contrib/vhost-user-blk/vhost-user-blk.c | 109 ++++++++++++++----------
>  1 file changed, 65 insertions(+), 44 deletions(-)
> 
> diff --git a/contrib/vhost-user-blk/vhost-user-blk.c b/contrib/vhost-user-blk/vhost-user-blk.c
> index ae61034656..96c43bb58d 100644
> --- a/contrib/vhost-user-blk/vhost-user-blk.c
> +++ b/contrib/vhost-user-blk/vhost-user-blk.c
> @@ -576,70 +576,91 @@ vub_new(char *blk_file)
>      return vdev_blk;
>  }
>  
> +static int opt_fdnum = -1;
> +static char *opt_socket_path;
> +static char *opt_blk_file;
> +static gboolean opt_print_caps;
> +static gboolean opt_read_only;
> +
> +

single empty line please.

> +static GOptionEntry entries[] = {
> +    { "print-capabilities", 'c', 0, G_OPTION_ARG_NONE, &opt_print_caps,
> +      "Print capabilities", NULL },
> +    { "fd", 'f', 0, G_OPTION_ARG_INT, &opt_fdnum,
> +      "Use inherited fd socket", "FDNUM" },
> +    { "socket-path", 's', 0, G_OPTION_ARG_FILENAME, &opt_socket_path,
> +      "Use UNIX socket path", "PATH" },
> +    {"blk-file", 'b', 0, G_OPTION_ARG_FILENAME, &opt_blk_file,
> +     "block device or file path", "PATH"},
> +    { "read-only", 'r', 0, G_OPTION_ARG_NONE, &opt_read_only,
> +      "Enable read-only", NULL }
> +};
> +
>  int main(int argc, char **argv)
>  {
> -    int opt;
> -    char *unix_socket = NULL;
> -    char *blk_file = NULL;
> -    bool enable_ro = false;
>      int lsock = -1, csock = -1;
>      VubDev *vdev_blk = NULL;
> +    GError *error = NULL;
> +    GOptionContext *context;
>  
> -    while ((opt = getopt(argc, argv, "b:rs:h")) != -1) {
> -        switch (opt) {
> -        case 'b':
> -            blk_file = g_strdup(optarg);
> -            break;
> -        case 's':
> -            unix_socket = g_strdup(optarg);
> -            break;
> -        case 'r':
> -            enable_ro = true;
> -            break;
> -        case 'h':
> -        default:
> -            printf("Usage: %s [ -b block device or file, -s UNIX domain socket"
> -                   " | -r Enable read-only ] | [ -h ]\n", argv[0]);
> -            return 0;
> +    context = g_option_context_new(NULL);
> +    g_option_context_add_main_entries(context, entries, NULL);
> +    if (!g_option_context_parse(context, &argc, &argv, &error)) {
> +        g_printerr("Option parsing failed: %s\n", error->message);
> +        exit(EXIT_FAILURE);
> +    }
> +    if (opt_print_caps) {
> +        g_print("{\n");
> +        g_print("  \"type\": \"blk\",\n");
> +        g_print("  \"features\": [\n");
> +        g_print("    \"read-only\",\n");
> +        g_print("    \"blk-file\"\n");
> +        g_print("  ]\n");
> +        g_print("}\n");
> +        exit(EXIT_SUCCESS);
> +    }
> +
> +    if (!opt_blk_file) {
> +        g_print("%s\n", g_option_context_get_help(context, true, NULL));
> +        exit(EXIT_FAILURE);
> +    }
> +
> +    if (opt_socket_path) {
> +        lsock = unix_sock_new(opt_socket_path);
> +        if (lsock < 0) {
> +            exit(EXIT_FAILURE);
>          }
> +    } else if (opt_fdnum < 0) {
> +        g_print("%s\n", g_option_context_get_help(context, true, NULL));
> +        exit(EXIT_FAILURE);
> +    } else {
> +        lsock = opt_fdnum;
>      }
>  
> -    if (!unix_socket || !blk_file) {
> -        printf("Usage: %s [ -b block device or file, -s UNIX domain socket"
> -               " | -r Enable read-only ] | [ -h ]\n", argv[0]);
> -        return -1;
> -    }
> -
> -    lsock = unix_sock_new(unix_socket);
> -    if (lsock < 0) {
> -        goto err;
> -    }
> -
> -    csock = accept(lsock, (void *)0, (void *)0);
> +    csock = accept(lsock, NULL, NULL);
>      if (csock < 0) {
> -        fprintf(stderr, "Accept error %s\n", strerror(errno));
> -        goto err;
> +        g_printerr("Accept error %s\n", strerror(errno));
> +        exit(EXIT_FAILURE);
>      }
>  
> -    vdev_blk = vub_new(blk_file);
> +    vdev_blk = vub_new(opt_blk_file);
>      if (!vdev_blk) {
> -        goto err;
> +        exit(EXIT_FAILURE);
>      }
> -    if (enable_ro) {
> +    if (opt_read_only) {
>          vdev_blk->enable_ro = true;
>      }
>  
>      if (!vug_init(&vdev_blk->parent, VHOST_USER_BLK_MAX_QUEUES, csock,
>                    vub_panic_cb, &vub_iface)) {
> -        fprintf(stderr, "Failed to initialized libvhost-user-glib\n");
> -        goto err;
> +        g_printerr("Failed to initialize libvhost-user-glib\n");
> +        exit(EXIT_FAILURE);
>      }
>  
>      g_main_loop_run(vdev_blk->loop);
> -
> +    g_main_loop_unref(vdev_blk->loop);
> +    g_option_context_free(context);
>      vug_deinit(&vdev_blk->parent);
> -
> -err:
>      vub_free(vdev_blk);
>      if (csock >= 0) {
>          close(csock);
> @@ -647,8 +668,8 @@ err:
>      if (lsock >= 0) {
>          close(lsock);
>      }
> -    g_free(unix_socket);
> -    g_free(blk_file);
> +    g_free(opt_socket_path);
> +    g_free(opt_blk_file);
>  
>      return 0;
>  }
> -- 
> 2.21.0