hw/9pfs: Add support to use named socket for proxy FS

Add option to use named socket for communicating between proxy helper
and qemu proxy FS. Access to socket can be given by using command line
options -u and -g.

Signed-off-by: M. Mohan Kumar <mohan@in.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

1 files changed, 45 insertions, 7 deletions

diff --git a/hw/9pfs/virtio-9p-proxy.c b/hw/9pfs/virtio-9p-proxy.c
index 415bd21815..44f5fc4f7e 100644
--- a/hw/9pfs/virtio-9p-proxy.c
+++ b/hw/9pfs/virtio-9p-proxy.c
@@ -1095,15 +1095,49 @@ static int proxy_ioc_getversion(FsContext *fs_ctx, V9fsPath *path,
     return err;
 }
 
+static int connect_namedsocket(const char *path)
+{
+    int sockfd, size;
+    struct sockaddr_un helper;
+
+    sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
+    if (sockfd < 0) {
+        fprintf(stderr, "socket %s\n", strerror(errno));
+        return -1;
+    }
+    strcpy(helper.sun_path, path);
+    helper.sun_family = AF_UNIX;
+    size = strlen(helper.sun_path) + sizeof(helper.sun_family);
+    if (connect(sockfd, (struct sockaddr *)&helper, size) < 0) {
+        fprintf(stderr, "socket error\n");
+        return -1;
+    }
+
+    /* remove the socket for security reasons */
+    unlink(path);
+    return sockfd;
+}
+
 static int proxy_parse_opts(QemuOpts *opts, struct FsDriverEntry *fs)
 {
+    const char *socket = qemu_opt_get(opts, "socket");
     const char *sock_fd = qemu_opt_get(opts, "sock_fd");
 
-    if (sock_fd) {
-        fprintf(stderr, "sock_fd option not specified\n");
+    if (!socket && !sock_fd) {
+        fprintf(stderr, "socket and sock_fd none of the option specified\n");
+        return -1;
+    }
+    if (socket && sock_fd) {
+        fprintf(stderr, "Both socket and sock_fd options specified\n");
         return -1;
     }
-    fs->path = g_strdup(sock_fd);
+    if (socket) {
+        fs->path = g_strdup(socket);
+        fs->export_flags = V9FS_PROXY_SOCK_NAME;
+    } else {
+        fs->path = g_strdup(sock_fd);
+        fs->export_flags = V9FS_PROXY_SOCK_FD;
+    }
     return 0;
 }
 
@@ -1112,10 +1146,14 @@ static int proxy_init(FsContext *ctx)
     V9fsProxy *proxy = g_malloc(sizeof(V9fsProxy));
     int sock_id;
 
-    sock_id = atoi(ctx->fs_root);
-    if (sock_id < 0) {
-        fprintf(stderr, "socket descriptor not initialized\n");
-        return -1;
+    if (ctx->export_flags & V9FS_PROXY_SOCK_NAME) {
+        sock_id = connect_namedsocket(ctx->fs_root);
+    } else {
+        sock_id = atoi(ctx->fs_root);
+        if (sock_id < 0) {
+            fprintf(stderr, "socket descriptor not initialized\n");
+            return -1;
+        }
     }
     g_free(ctx->fs_root);