virtio-9p: Use layered xattr approach

We would need this to make sure we handle the mapped
security model correctly for different xattr names.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>

1 files changed, 152 insertions, 0 deletions

diff --git a/hw/virtio-9p-xattr.c b/hw/virtio-9p-xattr.c
new file mode 100644
index 0000000..5ddc3c9
--- /dev/null
+++ b/hw/virtio-9p-xattr.c
@@ -0,0 +1,152 @@
+/*
+ * Virtio 9p  xattr callback
+ *
+ * Copyright IBM, Corp. 2010
+ *
+ * Authors:
+ * Aneesh Kumar K.V <aneesh.kumar@linux.vnet.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 "virtio.h"
+#include "virtio-9p.h"
+#include "file-op-9p.h"
+#include "virtio-9p-xattr.h"
+
+
+static XattrOperations *get_xattr_operations(XattrOperations **h,
+                                             const char *name)
+{
+    XattrOperations *xops;
+    for (xops = *(h)++; xops != NULL; xops = *(h)++) {
+        if (!strncmp(name, xops->name, strlen(xops->name))) {
+            return xops;
+        }
+    }
+    return NULL;
+}
+
+ssize_t v9fs_get_xattr(FsContext *ctx, const char *path,
+                       const char *name, void *value, size_t size)
+{
+    XattrOperations *xops = get_xattr_operations(ctx->xops, name);
+    if (xops) {
+        return xops->getxattr(ctx, path, name, value, size);
+    }
+    errno = -EOPNOTSUPP;
+    return -1;
+}
+
+ssize_t pt_listxattr(FsContext *ctx, const char *path,
+                     char *name, void *value, size_t size)
+{
+    int name_size = strlen(name) + 1;
+    if (!value) {
+        return name_size;
+    }
+
+    if (size < name_size) {
+        errno = ERANGE;
+        return -1;
+    }
+
+    strncpy(value, name, name_size);
+    return name_size;
+}
+
+
+/*
+ * Get the list and pass to each layer to find out whether
+ * to send the data or not
+ */
+ssize_t v9fs_list_xattr(FsContext *ctx, const char *path,
+                        void *value, size_t vsize)
+{
+    ssize_t size = 0;
+    void *ovalue = value;
+    XattrOperations *xops;
+    char *orig_value, *orig_value_start;
+    ssize_t xattr_len, parsed_len = 0, attr_len;
+
+    /* Get the actual len */
+    xattr_len = llistxattr(rpath(ctx, path), value, 0);
+
+    /* Now fetch the xattr and find the actual size */
+    orig_value = qemu_malloc(xattr_len);
+    xattr_len = llistxattr(rpath(ctx, path), orig_value, xattr_len);
+
+    /* store the orig pointer */
+    orig_value_start = orig_value;
+    while (xattr_len > parsed_len) {
+        xops = get_xattr_operations(ctx->xops, orig_value);
+        if (!xops) {
+            goto next_entry;
+        }
+
+        if (!value) {
+            size += xops->listxattr(ctx, path, orig_value, value, vsize);
+        } else {
+            size = xops->listxattr(ctx, path, orig_value, value, vsize);
+            if (size < 0) {
+                goto err_out;
+            }
+            value += size;
+            vsize -= size;
+        }
+next_entry:
+        /* Got the next entry */
+        attr_len = strlen(orig_value) + 1;
+        parsed_len += attr_len;
+        orig_value += attr_len;
+    }
+    if (value) {
+        size = value - ovalue;
+    }
+
+err_out:
+    qemu_free(orig_value_start);
+    return size;
+}
+
+int v9fs_set_xattr(FsContext *ctx, const char *path, const char *name,
+                   void *value, size_t size, int flags)
+{
+    XattrOperations *xops = get_xattr_operations(ctx->xops, name);
+    if (xops) {
+        return xops->setxattr(ctx, path, name, value, size, flags);
+    }
+    errno = -EOPNOTSUPP;
+    return -1;
+
+}
+
+int v9fs_remove_xattr(FsContext *ctx,
+                      const char *path, const char *name)
+{
+    XattrOperations *xops = get_xattr_operations(ctx->xops, name);
+    if (xops) {
+        return xops->removexattr(ctx, path, name);
+    }
+    errno = -EOPNOTSUPP;
+    return -1;
+
+}
+
+XattrOperations *mapped_xattr_ops[] = {
+    &mapped_user_xattr,
+    NULL,
+};
+
+XattrOperations *passthrough_xattr_ops[] = {
+    &passthrough_user_xattr,
+    NULL,
+};
+
+/* for .user none model should be same as passthrough */
+XattrOperations *none_xattr_ops[] = {
+    &passthrough_user_xattr,
+    NULL,
+};