[PATCH 07/13] Add BINDER_GET_NODE_DEBUG_INFO ioctl

Martijn Coenen
2017-08-25T09:35:22Z

From: Colin Cross <ccross@android.com>

The BINDER_GET_NODE_DEBUG_INFO ioctl will return debug info on
a node. Each successive call reusing the previous return value
will return the next node. The data will be used by
libmemunreachable to mark the pointers with kernel references
as reachable.

Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Martijn Coenen <maco@android.com>
---
drivers/android/binder.c | 43 +++++++++++++++++++++++++++++++++++++
include/uapi/linux/android/binder.h | 14 ++++++++++++
2 files changed, 57 insertions(+)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index e6778c696942..8eee4716e777 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -4546,6 +4546,31 @@ static int binder_ioctl_set_ctx_mgr(struct file *filp)
return ret;
}

+static int binder_ioctl_get_node_debug_info(struct binder_proc *proc,
+ struct binder_node_debug_info *info)
+{
+ struct rb_node *n;
+ binder_uintptr_t ptr = info->ptr;
+
+ memset(info, 0, sizeof(*info));
+
+ binder_inner_proc_lock(proc);
+ for (n = rb_first(&proc->nodes); n != NULL; n = rb_next(n)) {
+ struct binder_node *node = rb_entry(n, struct binder_node,
+ rb_node);
+ if (node->ptr > ptr) {
+ info->ptr = node->ptr;
+ info->cookie = node->cookie;
+ info->has_strong_ref = node->has_strong_ref;
+ info->has_weak_ref = node->has_weak_ref;
+ break;
+ }
+ }
+ binder_inner_proc_unlock(proc);
+
+ return 0;
+}
+
static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
int ret;
@@ -4613,6 +4638,24 @@ static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
}
break;
}
+ case BINDER_GET_NODE_DEBUG_INFO: {
+ struct binder_node_debug_info info;
+
+ if (copy_from_user(&info, ubuf, sizeof(info))) {
+ ret = -EFAULT;
+ goto err;
+ }
+
+ ret = binder_ioctl_get_node_debug_info(proc, &info);
+ if (ret < 0)
+ goto err;
+
+ if (copy_to_user(ubuf, &info, sizeof(info))) {
+ ret = -EFAULT;
+ goto err;
+ }
+ break;
+ }
default:
ret = -EINVAL;
goto err;
diff --git a/include/uapi/linux/android/binder.h b/include/uapi/linux/android/binder.h
index 70e252bf0be0..5539933b3491 100644
--- a/include/uapi/linux/android/binder.h
+++ b/include/uapi/linux/android/binder.h
@@ -233,6 +233,19 @@ struct binder_version {
#define BINDER_CURRENT_PROTOCOL_VERSION 8
#endif

+/*
+ * Use with BINDER_GET_NODE_DEBUG_INFO, driver reads ptr, writes to all fields.
+ * Set ptr to NULL for the first call to get the info for the first node, and
+ * then repeat the call passing the previously returned value to get the next
+ * nodes. ptr will be 0 when there are no more nodes.
+ */
+struct binder_node_debug_info {
+ binder_uintptr_t ptr;
+ binder_uintptr_t cookie;
+ __u32 has_strong_ref;
+ __u32 has_weak_ref;
+};
+
#define BINDER_WRITE_READ _IOWR('b', 1, struct binder_write_read)
#define BINDER_SET_IDLE_TIMEOUT _IOW('b', 3, __s64)
#define BINDER_SET_MAX_THREADS _IOW('b', 5, __u32)
@@ -240,6 +253,7 @@ struct binder_version {
#define BINDER_SET_CONTEXT_MGR _IOW('b', 7, __s32)
#define BINDER_THREAD_EXIT _IOW('b', 8, __s32)
#define BINDER_VERSION _IOWR('b', 9, struct binder_version)
+#define BINDER_GET_NODE_DEBUG_INFO _IOWR('b', 11, struct binder_node_debug_info)

/*
* NOTE: Two special error codes you should check for when calling
--
2.14.1.480.gb18f417b89-goog