Use ashmem instead of memfd_create on Android. (#816)

* Use ashmem instead of memfd_create on Android.

* Fix code styling issues.

* fix small mistake in merge commit

Co-authored-by: RSDuck <RSDuck@users.noreply.github.com>

1 files changed, 35 insertions, 8 deletions

diff --git a/src/ARMJIT_Memory.cpp b/src/ARMJIT_Memory.cpp
index cc0f149..f9f82aa 100644
--- a/src/ARMJIT_Memory.cpp
+++ b/src/ARMJIT_Memory.cpp
@@ -10,6 +10,12 @@
 #include <signal.h>
 #endif
 
+#if defined(__ANDROID__)
+#include <dlfcn.h>
+#include <linux/ashmem.h>
+#include <sys/ioctl.h>
+#endif
+
 #include "ARMJIT_Memory.h"
 
 #include "ARMJIT_Internal.h"
@@ -58,6 +64,10 @@ struct FaultDescription
 bool FaultHandler(FaultDescription& faultDesc);
 }
 
+#if defined(__ANDROID__)
+#define ASHMEM_DEVICE "/dev/ashmem"
+#endif
+
 #if defined(__SWITCH__)
 // with LTO the symbols seem to be not properly overriden
 // if they're somewhere else
@@ -712,14 +722,31 @@ void Init()
     FastMem7Start = MemoryBase + AddrSpaceSize;
     MemoryBase = MemoryBase + AddrSpaceSize*2;
 
-    #ifdef __APPLE__
-        char* fastmemPidName = new char[snprintf(NULL, 0, "melondsfastmem%d", getpid()) + 1];
-        sprintf(fastmemPidName, "melondsfastmem%d", getpid());
-        MemoryFile = shm_open(fastmemPidName, O_RDWR|O_CREAT, 0600);
-        delete[] fastmemPidName;
-    #else    
-        MemoryFile = memfd_create("melondsfastmem", 0);
-    #endif
+#if defined(__ANDROID__)
+    static void* libandroid = dlopen("libandroid.so", RTLD_LAZY | RTLD_LOCAL);
+    using type_ASharedMemory_create = int(*)(const char* name, size_t size);
+    static void* symbol = dlsym(libandroid, "ASharedMemory_create");
+    static auto shared_memory_create = reinterpret_cast<type_ASharedMemory_create>(symbol);
+
+    if (shared_memory_create)
+    {
+        MemoryFile = shared_memory_create("melondsfastmem", MemoryTotalSize);
+    }
+    else
+    {
+        int fd = open(ASHMEM_DEVICE, O_RDWR);
+        ioctl(fd, ASHMEM_SET_NAME, "melondsfastmem");
+        ioctl(fd, ASHMEM_SET_SIZE, MemoryTotalSize);
+        MemoryFile = fd;
+    }
+#elif defined(__APPLE__)
+    char* fastmemPidName = new char[snprintf(NULL, 0, "melondsfastmem%d", getpid()) + 1];
+    sprintf(fastmemPidName, "melondsfastmem%d", getpid());
+    MemoryFile = shm_open(fastmemPidName, O_RDWR|O_CREAT, 0600);
+    delete[] fastmemPidName;
+#else
+    MemoryFile = memfd_create("melondsfastmem", 0);
+#endif
     ftruncate(MemoryFile, MemoryTotalSize);
 
     struct sigaction sa;