The current Ion ioctls lack a good way to tell what ioctls are
available. Introduce an ioctl to give an ABI version. This way when the
ABI inevitably gets screwed up userspace will have a way to tell what
version of the screw up is available.
Signed-off-by: Laura Abbott <labb...@redhat.com>
---
drivers/staging/android/ion/ion-ioctl.c | 53 ++++++++++++++++++++++++++-------
drivers/staging/android/uapi/ion.h | 22 ++++++++++++++
2 files changed, 65 insertions(+), 10 deletions(-)
diff --git a/drivers/staging/android/ion/ion-ioctl.c
b/drivers/staging/android/ion/ion-ioctl.c
index 341ba7d..53b9520 100644
--- a/drivers/staging/android/ion/ion-ioctl.c
+++ b/drivers/staging/android/ion/ion-ioctl.c
@@ -22,6 +22,29 @@
#include "ion_priv.h"
#include "compat_ion.h"
+union ion_ioctl_arg {
+ struct ion_fd_data fd;
+ struct ion_allocation_data allocation;
+ struct ion_handle_data handle;
+ struct ion_custom_data custom;
+ struct ion_abi_version abi_version;
+};
+
+static int validate_ioctl_arg(unsigned int cmd, union ion_ioctl_arg *arg)
+{
+ int ret = 0;
+
+ switch (cmd) {
+ case ION_IOC_ABI_VERSION:
+ ret = arg->abi_version.reserved != 0;
+ break;
+ default:
+ break;
+ }
+
+ return ret ? -EINVAL : 0;
+}
+
/* fix up the cases where the ioctl direction bits are incorrect */
static unsigned int ion_ioctl_dir(unsigned int cmd)
{
@@ -42,22 +65,27 @@ long ion_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg)
struct ion_handle *cleanup_handle = NULL;
int ret = 0;
unsigned int dir;
-
- union {
- struct ion_fd_data fd;
- struct ion_allocation_data allocation;
- struct ion_handle_data handle;
- struct ion_custom_data custom;
- } data;
+ union ion_ioctl_arg data;
dir = ion_ioctl_dir(cmd);
if (_IOC_SIZE(cmd) > sizeof(data))
return -EINVAL;
- if (dir & _IOC_WRITE)
- if (copy_from_user(&data, (void __user *)arg, _IOC_SIZE(cmd)))
- return -EFAULT;
+ /*
+ * The copy_from_user is unconditional here for both read and write
+ * to do the validate. If there is no write for the ioctl, the
+ * buffer is cleared
+ */
+ if (copy_from_user(&data, (void __user *)arg, _IOC_SIZE(cmd)))
+ return -EFAULT;
+
+ ret = validate_ioctl_arg(cmd, &data);
+ if (WARN_ON_ONCE(ret))
+ return ret;
+
+ if (!(dir & _IOC_WRITE))
+ memset(&data, 0, sizeof(data));
switch (cmd) {
case ION_IOC_ALLOC:
@@ -129,6 +157,11 @@ long ion_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg)
data.custom.arg);
break;
}
+ case ION_IOC_ABI_VERSION:
+ {
+ data.abi_version.abi_version = ION_ABI_VERSION;
+ break;
+ }
default:
return -ENOTTY;
}
diff --git a/drivers/staging/android/uapi/ion.h
b/drivers/staging/android/uapi/ion.h
index a9c4e8b..7ca4e8b 100644
--- a/drivers/staging/android/uapi/ion.h
+++ b/drivers/staging/android/uapi/ion.h
@@ -19,6 +19,7 @@
#include <linux/ioctl.h>
#include <linux/types.h>
+#include <linux/version.h>
typedef int ion_user_handle_t;
@@ -128,6 +129,19 @@ struct ion_custom_data {
unsigned long arg;
};
+/**
+ * struct ion_abi_version
+ *
+ * @version - current ABI version
+ */
+
+#define ION_ABI_VERSION KERNEL_VERSION(0, 1, 0)
+
+struct ion_abi_version {
+ __u32 abi_version;
+ __u32 reserved;
+};
+
#define ION_IOC_MAGIC 'I'
/**
@@ -194,4 +208,12 @@ struct ion_custom_data {
*/
#define ION_IOC_CUSTOM _IOWR(ION_IOC_MAGIC, 6, struct ion_custom_data)
+/**
+ * DOC: ION_IOC_ABI_VERSION - return ABI version
+ *
+ * Returns the ABI version of this driver.
+ */
+#define ION_IOC_ABI_VERSION _IOR(ION_IOC_MAGIC, 8, \
+ struct ion_abi_version)
+
#endif /* _UAPI_LINUX_ION_H */
--
2.7.4
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