[PATCH] [PATCH RFC v4] Implements Backend Program conventions for vhost-user-scsi

[PATCH] [PATCH RFC v4] Implements Backend Program conventions for vhost-user-scsi

[Sakshi Kaushik]

Signed-off-by: Sakshi Kaushik <sakshikaushik717@gmail.com>
---
 contrib/vhost-user-scsi/vhost-user-scsi.c | 78 +++++++++++++++--------
 1 file changed, 52 insertions(+), 26 deletions(-)

diff --git a/contrib/vhost-user-scsi/vhost-user-scsi.c b/contrib/vhost-user-scsi/vhost-user-scsi.c
index 4f6e3e2a24..0c38c2988c 100644
--- a/contrib/vhost-user-scsi/vhost-user-scsi.c
+++ b/contrib/vhost-user-scsi/vhost-user-scsi.c
@@ -351,34 +351,58 @@ fail:
 
 /** vhost-user-scsi **/
 
+static int opt_fdnum = -1;
+static char *opt_socket_path;
+static gboolean opt_print_caps;
+static char *iscsi_uri;
+
+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" },
+    { "iscsi_uri", 'i', 0, G_OPTION_ARG_FILENAME, &iscsi_uri,
+      "Use inherited fd socket", "FDNUM" },
+    { "socket-path", 's', 0, G_OPTION_ARG_FILENAME, &opt_socket_path,
+      "Use UNIX socket path", "PATH" }
+};
+
 int main(int argc, char **argv)
 {
     VusDev *vdev_scsi = NULL;
-    char *unix_fn = NULL;
-    char *iscsi_uri = NULL;
-    int lsock = -1, csock = -1, opt, err = EXIT_SUCCESS;
-
-    while ((opt = getopt(argc, argv, "u:i:")) != -1) {
-        switch (opt) {
-        case 'h':
-            goto help;
-        case 'u':
-            unix_fn = g_strdup(optarg);
-            break;
-        case 'i':
-            iscsi_uri = g_strdup(optarg);
-            break;
-        default:
-            goto help;
-        }
+    int lsock = -1, csock = -1, err = EXIT_SUCCESS;
+
+    GError *error = NULL;
+    GOptionContext *context;
+
+    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 (!unix_fn || !iscsi_uri) {
+
+    if (opt_print_caps) {
+        g_print("{\n");
+        g_print("  \"type\": \"scsi\"\n");
+        g_print("}\n");
+        goto out;
+    }
+
+    if (!opt_socket_path || !iscsi_uri) {
         goto help;
     }
 
-    lsock = unix_sock_new(unix_fn);
-    if (lsock < 0) {
-        goto err;
+    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;
     }
 
     csock = accept(lsock, NULL, NULL);
@@ -408,7 +432,7 @@ out:
     if (vdev_scsi) {
         g_main_loop_unref(vdev_scsi->loop);
         g_free(vdev_scsi);
-        unlink(unix_fn);
+        unlink(opt_socket_path);
     }
     if (csock >= 0) {
         close(csock);
@@ -416,7 +440,7 @@ out:
     if (lsock >= 0) {
         close(lsock);
     }
-    g_free(unix_fn);
+    g_free(opt_socket_path);
     g_free(iscsi_uri);
 
     return err;
@@ -426,10 +450,12 @@ err:
     goto out;
 
 help:
-    fprintf(stderr, "Usage: %s [ -u unix_sock_path -i iscsi_uri ] | [ -h ]\n",
+    fprintf(stderr, "Usage: %s [ -s socket-path -i iscsi_uri -f fd -p print-capabilities ] | [ -h ]\n",
             argv[0]);
-    fprintf(stderr, "          -u path to unix socket\n");
-    fprintf(stderr, "          -i iscsi uri for lun 0\n");
+    fprintf(stderr, "          -s, --socket-path=SOCKET_PATH path to unix socket\n");
+    fprintf(stderr, "          -i, --iscsi_uri=ISCSI_URI iscsi uri for lun 0\n");
+    fprintf(stderr, "          -f --fd=FILE_DESCRIPTOR file-descriptor\n");
+    fprintf(stderr, "          -p --print-capabilities=PRINT_CAPABILITIES denotes print-capabilities\n");
     fprintf(stderr, "          -h print help and quit\n");
 
     goto err;
-- 
2.17.1

Re: [PATCH] [PATCH RFC v4] Implements Backend Program conventions for vhost-user-scsi

[Stefan Hajnoczi]

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On Wed, Apr 06, 2022 at 11:24:10AM -0500, Sakshi Kaushik wrote:
> Signed-off-by: Sakshi Kaushik <sakshikaushik717@gmail.com>
> ---
>  contrib/vhost-user-scsi/vhost-user-scsi.c | 78 +++++++++++++++--------
>  1 file changed, 52 insertions(+), 26 deletions(-)

Thanks, I have applied this patch to my block-next branch!

I made a few small adjustments when merging. You do not need to resend
the patch. Details below:

> diff --git a/contrib/vhost-user-scsi/vhost-user-scsi.c b/contrib/vhost-user-scsi/vhost-user-scsi.c
> index 4f6e3e2a24..0c38c2988c 100644
> --- a/contrib/vhost-user-scsi/vhost-user-scsi.c
> +++ b/contrib/vhost-user-scsi/vhost-user-scsi.c
> @@ -351,34 +351,58 @@ fail:
>  
>  /** vhost-user-scsi **/
>  
> +static int opt_fdnum = -1;
> +static char *opt_socket_path;
> +static gboolean opt_print_caps;
> +static char *iscsi_uri;
> +
> +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" },
> +    { "iscsi_uri", 'i', 0, G_OPTION_ARG_FILENAME, &iscsi_uri,

For consistency with --print-capabilities and --socket-path this option
should be called --iscsi-uri.

> +      "Use inherited fd socket", "FDNUM" },
> +    { "socket-path", 's', 0, G_OPTION_ARG_FILENAME, &opt_socket_path,
> +      "Use UNIX socket path", "PATH" }

A zero terminator is required here so
g_option_context_add_main_entries() knows when the array ends.

> +};
> +
>  int main(int argc, char **argv)
>  {
>      VusDev *vdev_scsi = NULL;
> -    char *unix_fn = NULL;
> -    char *iscsi_uri = NULL;
> -    int lsock = -1, csock = -1, opt, err = EXIT_SUCCESS;
> -
> -    while ((opt = getopt(argc, argv, "u:i:")) != -1) {
> -        switch (opt) {
> -        case 'h':
> -            goto help;
> -        case 'u':
> -            unix_fn = g_strdup(optarg);
> -            break;
> -        case 'i':
> -            iscsi_uri = g_strdup(optarg);
> -            break;
> -        default:
> -            goto help;
> -        }
> +    int lsock = -1, csock = -1, err = EXIT_SUCCESS;
> +
> +    GError *error = NULL;
> +    GOptionContext *context;
> +
> +    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 (!unix_fn || !iscsi_uri) {
> +
> +    if (opt_print_caps) {
> +        g_print("{\n");
> +        g_print("  \"type\": \"scsi\"\n");
> +        g_print("}\n");
> +        goto out;
> +    }
> +
> +    if (!opt_socket_path || !iscsi_uri) {

This check rejects --fd and only allows --socket-path. We can drop
!opt_socket_path since the if statement below checks that already.

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