diff --git a/include/cutils/native_handle.h b/include/cutils/native_handle.h index 813dadc7c..7d6a98802 100644 --- a/include/cutils/native_handle.h +++ b/include/cutils/native_handle.h @@ -17,10 +17,17 @@ #ifndef NATIVE_HANDLE_H_ #define NATIVE_HANDLE_H_ +#include + #ifdef __cplusplus extern "C" { #endif +/* Declare a char array for use with native_handle_init */ +#define NATIVE_HANDLE_DECLARE_STORAGE(name, maxFds, maxInts) \ + alignas(native_handle_t) char name[ \ + sizeof(native_handle_t) + sizeof(int) * (maxFds + maxInts)] + typedef struct native_handle { int version; /* sizeof(native_handle_t) */ @@ -46,6 +53,14 @@ typedef struct native_handle */ int native_handle_close(const native_handle_t* h); +/* + * native_handle_init + * + * Initializes a native_handle_t from storage. storage must be declared with + * NATIVE_HANDLE_DECLARE_STORAGE. numFds and numInts must not respectively + * exceed maxFds and maxInts used to declare the storage. + */ +native_handle_t* native_handle_init(char* storage, int numFds, int numInts); /* * native_handle_create diff --git a/libcutils/native_handle.c b/libcutils/native_handle.c index cae146d45..9f4840a59 100644 --- a/libcutils/native_handle.c +++ b/libcutils/native_handle.c @@ -28,6 +28,20 @@ static const int kMaxNativeFds = 1024; static const int kMaxNativeInts = 1024; +native_handle_t* native_handle_init(char* storage, int numFds, int numInts) +{ + if ((uintptr_t) storage % alignof(native_handle_t)) { + return NULL; + } + + native_handle_t* handle = (native_handle_t*) storage; + handle->version = sizeof(native_handle_t); + handle->numFds = numFds; + handle->numInts = numInts; + + return handle; +} + native_handle_t* native_handle_create(int numFds, int numInts) { if (numFds < 0 || numInts < 0 || numFds > kMaxNativeFds || numInts > kMaxNativeInts) {