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 labbott@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 */