[PATCH 18/24] xen: add "capabilities" file

Jeremy Fitzhardinge
2009-03-13T08:19:13Z

The xenfs capabilities file allows usermode to determine what
capabilities the domain has. The only one at present is "control_d"
in a privileged domain.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
---
drivers/xen/xenfs/super.c | 19 ++++++++++++++++++-
1 files changed, 18 insertions(+), 1 deletions(-)

diff --git a/drivers/xen/xenfs/super.c b/drivers/xen/xenfs/super.c
index 515741a..6559e0c 100644
--- a/drivers/xen/xenfs/super.c
+++ b/drivers/xen/xenfs/super.c
@@ -20,10 +20,27 @@
MODULE_DESCRIPTION("Xen filesystem");
MODULE_LICENSE("GPL");

+static ssize_t capabilities_read(struct file *file, char __user *buf,
+ size_t size, loff_t *off)
+{
+ char *tmp = "";
+
+ if (xen_initial_domain())
+ tmp = "control_d\n";
+
+ return simple_read_from_buffer(buf, size, off, tmp, strlen(tmp));
+}
+
+static const struct file_operations capabilities_file_ops = {
+ .read = capabilities_read,
+};
+
static int xenfs_fill_super(struct super_block *sb, void *data, int silent)
{
static struct tree_descr xenfs_files[] = {
- [2] = {"xenbus", &xenbus_file_ops, S_IRUSR|S_IWUSR},
+ [1] = {},
+ { "xenbus", &xenbus_file_ops, S_IRUSR|S_IWUSR },
+ { "capabilities", &capabilities_file_ops, S_IRUGO },
{""},
};

--
1.6.0.6