From f5148527919574c2e2ff74c21eeb31a0cbea57e6 Mon Sep 17 00:00:00 2001
From: Filippo Scognamiglio <flscogna@gmail.com>
Date: Mon, 3 Feb 2020 20:57:34 +0100
Subject: [PATCH] Use ASharedMemory api instead of direct access to /dev/ashmem
 which is deprecated.

---
 Common/MemArenaAndroid.cpp | 41 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 40 insertions(+), 1 deletion(-)

diff --git a/Common/MemArenaAndroid.cpp b/Common/MemArenaAndroid.cpp
index 31eda9d3d0..4a9242b2df 100644
--- a/Common/MemArenaAndroid.cpp
+++ b/Common/MemArenaAndroid.cpp
@@ -30,6 +30,8 @@
 #include <cerrno>
 #include <sys/ioctl.h>
 #include <linux/ashmem.h>
+#include <dlfcn.h>
+#include <sys/system_properties.h>
 
 // Hopefully this ABI will never change...
 
@@ -39,11 +41,41 @@ bool MemArena::NeedsProbing() {
 	return false;
 }
 
+static int get_sdk_version() {
+	char sdk[PROP_VALUE_MAX] = {0};
+	if (__system_property_get("ro.build.version.sdk", sdk) != 0) {
+		return atoi(sdk);
+	}
+	return -1;
+}
+
 // ashmem_create_region - creates a new ashmem region and returns the file
 // descriptor, or <0 on error
+// This function is defined in much later version of the ndk, so we can only access it via dlopen().
 // `name' is an optional label to give the region (visible in /proc/pid/maps)
 // `size' is the size of the region, in page-aligned bytes
 static int ashmem_create_region(const char *name, size_t size) {
+	static void* handle = dlopen("libandroid.so", RTLD_LAZY | RTLD_LOCAL);
+	using type_ASharedMemory_create = int(*)(const char *name, size_t size);
+	static type_ASharedMemory_create function_create = nullptr;
+
+	if (handle != nullptr) {
+		function_create =
+			reinterpret_cast<type_ASharedMemory_create>(dlsym(handle, "ASharedMemory_create"));
+	}
+
+	if (function_create != nullptr) {
+		return function_create(name, size);
+	} else {
+		return -1;
+	}
+}
+
+// legacy_ashmem_create_region - creates a new ashmem region and returns the file
+// descriptor, or <0 on error
+// `name' is an optional label to give the region (visible in /proc/pid/maps)
+// `size' is the size of the region, in page-aligned bytes
+static int legacy_ashmem_create_region(const char *name, size_t size) {
 	int fd = open(ASHMEM_DEVICE, O_RDWR);
 	if (fd < 0)
 		return fd;
@@ -76,7 +108,14 @@ size_t MemArena::roundup(size_t x) {
 
 void MemArena::GrabLowMemSpace(size_t size) {
 	// Use ashmem so we don't have to allocate a file on disk!
-	fd = ashmem_create_region("PPSSPP_RAM", size);
+	const char* name = "PPSSPP_RAM";
+
+	// Since version 26 Android provides a new api for accessing SharedMemory.
+	if (get_sdk_version() >= 26) {
+		fd = ashmem_create_region(name, size);
+	} else {
+		fd = legacy_ashmem_create_region(name, size);
+	}
 	// Note that it appears that ashmem is pinned by default, so no need to pin.
 	if (fd < 0) {
 		ERROR_LOG(MEMMAP, "Failed to grab ashmem space of size: %08x  errno: %d", (int)size, (int)(errno));