virtio-9p: Create a syntactic shortcut for the file-system pass-thru

Currently the commandline to create a virtual-filesystem pass-through between
the guest and the host is as follows:
#qemu -fsdev fstype,id=ID,path=path/to/share \
      -device virtio-9p-pci,fsdev=ID,mount_tag=tag \

This patch provides a syntactic short-cut to achieve the same as follows:
#qemu -virtfs fstype,path=path/to/share,mount_tag=tag

This will be internally expanded as:
#qemu -fsdev fstype,id=tag,path=path/to/share, \
      -device virtio-9p-pci,fsdev=tag,mount_tag=tag \

Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 56 insertions, 0 deletions

diff --git a/vl.c b/vl.c
index 37f46b6a5b..9caf96d399 100644
--- a/vl.c
+++ b/vl.c
@@ -3102,6 +3102,62 @@ int main(int argc, char **argv, char **envp)
                     exit(1);
                 }
                 break;
+            case QEMU_OPTION_virtfs: {
+                char *arg_fsdev = NULL;
+                char *arg_9p = NULL;
+                int len = 0;
+
+                opts = qemu_opts_parse(&qemu_virtfs_opts, optarg, 1);
+                if (!opts) {
+                    fprintf(stderr, "parse error: %s\n", optarg);
+                    exit(1);
+                }
+
+                len = strlen(",id=,path=");
+                len += strlen(qemu_opt_get(opts, "fstype"));
+                len += strlen(qemu_opt_get(opts, "mount_tag"));
+                len += strlen(qemu_opt_get(opts, "path"));
+                arg_fsdev = qemu_malloc((len + 1) * sizeof(*arg_fsdev));
+
+                if (!arg_fsdev) {
+                    fprintf(stderr, "No memory to parse -fsdev for %s\n",
+                            optarg);
+                    exit(1);
+                }
+
+                sprintf(arg_fsdev, "%s,id=%s,path=%s",
+                                qemu_opt_get(opts, "fstype"),
+                                qemu_opt_get(opts, "mount_tag"),
+                                qemu_opt_get(opts, "path"));
+
+                len = strlen("virtio-9p-pci,fsdev=,mount_tag=");
+                len += 2*strlen(qemu_opt_get(opts, "mount_tag"));
+                arg_9p = qemu_malloc((len + 1) * sizeof(*arg_9p));
+
+                if (!arg_9p) {
+                    fprintf(stderr, "No memory to parse -device for %s\n",
+                            optarg);
+                    exit(1);
+                }
+
+                sprintf(arg_9p, "virtio-9p-pci,fsdev=%s,mount_tag=%s",
+                                qemu_opt_get(opts, "mount_tag"),
+                                qemu_opt_get(opts, "mount_tag"));
+
+                if (!qemu_opts_parse(&qemu_fsdev_opts, arg_fsdev, 1)) {
+                    fprintf(stderr, "parse error [fsdev]: %s\n", optarg);
+                    exit(1);
+                }
+
+                if (!qemu_opts_parse(&qemu_device_opts, arg_9p, 1)) {
+                    fprintf(stderr, "parse error [device]: %s\n", optarg);
+                    exit(1);
+                }
+
+                qemu_free(arg_fsdev);
+                qemu_free(arg_9p);
+                break;
+            }
 #endif
             case QEMU_OPTION_serial:
                 add_device_config(DEV_SERIAL, optarg);