virtio-9p: Create a commandline option -fsdev

This patch creates a new command line option named -fsdev to hold any file
system specific information.

The option will currently hold the following attributes:
-fsdev fstype id=id,path=path_to_share
where
fstype: Type of the file system.
id:     Identifier used to refer to this fsdev
path:   The path on the host that is identified by this fsdev.

[aneesh.kumar@linux.vnet.ibm.com: Abstraction using FsContext]
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>

fsdev/qemu-fsdev.c

@@ -0,0 +1,70 @@
+/*
+ * Virtio 9p
+ *
+ * Copyright IBM, Corp. 2010
+ *
+ * Authors:
+ *  Gautham R Shenoy <ego@in.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+#include <stdio.h>
+#include <string.h>
+#include "qemu-fsdev.h"
+#include "qemu-queue.h"
+#include "osdep.h"
+#include "qemu-common.h"
+
+static QTAILQ_HEAD(FsTypeEntry_head, FsTypeListEntry) fstype_entries =
+    QTAILQ_HEAD_INITIALIZER(fstype_entries);
+
+static FsTypeTable FsTypes[] = {
+    { .name = "local", .ops = NULL},
+};
+
+int qemu_fsdev_add(QemuOpts *opts)
+{
+    struct FsTypeListEntry *fsle;
+    int i;
+
+    if (qemu_opts_id(opts) == NULL) {
+        fprintf(stderr, "fsdev: No id specified\n");
+        return -1;
+    }
+
+     for (i = 0; i < ARRAY_SIZE(FsTypes); i++) {
+        if (strcmp(FsTypes[i].name, qemu_opt_get(opts, "fstype")) == 0) {
+            break;
+        }
+    }
+
+    if (i == ARRAY_SIZE(FsTypes)) {
+        fprintf(stderr, "fsdev: fstype %s not found\n",
+                    qemu_opt_get(opts, "fstype"));
+        return -1;
+    }
+
+    fsle = qemu_malloc(sizeof(*fsle));
+
+    fsle->fse.fsdev_id = qemu_strdup(qemu_opts_id(opts));
+    fsle->fse.path = qemu_strdup(qemu_opt_get(opts, "path"));
+    fsle->fse.ops = FsTypes[i].ops;
+
+    QTAILQ_INSERT_TAIL(&fstype_entries, fsle, next);
+    return 0;
+
+}
+
+FsTypeEntry *get_fsdev_fsentry(char *id)
+{
+    struct FsTypeListEntry *fsle;
+
+    QTAILQ_FOREACH(fsle, &fstype_entries, next) {
+        if (strcmp(fsle->fse.fsdev_id, id) == 0) {
+            return &fsle->fse;
+        }
+    }
+    return NULL;
+}