Merge pull request #63 from ElDuderinos/master

Add support for MacOS Catalina+ (maxprot issue)

3 files changed, 25 insertions, 6 deletions

diff --git a/README.md b/README.md
index ff51c9c..01c905a 100644
--- a/README.md
+++ b/README.md
@@ -152,10 +152,8 @@ Known issues
   memory as executable, which prevents the use of trampolines.
 
   For example, on Fedora you can have such problems because of SELinux (though
-  you can disable it or exclude your files). On macOS Catalina the
-  `mprotect()` call inside `subhook_new` will fail with "Permission denied"
-  (see https://github.com/Zeex/subhook/issues/45).
-
+  you can disable it or exclude your files).
+  
 License
 -------
 
diff --git a/subhook.h b/subhook.h
index d2f6814..5633f39 100644
--- a/subhook.h
+++ b/subhook.h
@@ -41,9 +41,12 @@
 
 #if defined _WIN32 || defined __CYGWIN__
   #define SUBHOOK_WINDOWS
-#elif defined __linux__ || defined __APPLE__ \
+#elif defined __linux__ \
    || defined __FreeBSD__ || defined __OpenBSD__ || defined __NetBSD__
   #define SUBHOOK_UNIX
+  #elif defined __APPLE__
+  #define SUBHOOK_APPLE
+  #define SUBHOOK_UNIX
 #else
   #error Unsupported operating system
 #endif
diff --git a/subhook_unix.c b/subhook_unix.c
index 6a5410b..4d9c03a 100644
--- a/subhook_unix.c
+++ b/subhook_unix.c
@@ -27,6 +27,11 @@
 #include <stddef.h>
 #include <unistd.h>
 #include <sys/mman.h>
+#include "subhook.h"
+#ifdef SUBHOOK_APPLE
+#include <mach/mach.h>
+#endif
+
 
 #define SUBHOOK_CODE_PROTECT_FLAGS (PROT_READ | PROT_WRITE | PROT_EXEC)
 
@@ -36,7 +41,20 @@ int subhook_unprotect(void *address, size_t size) {
   pagesize = sysconf(_SC_PAGESIZE);
   address = (void *)((long)address & ~(pagesize - 1));
 
-  return mprotect(address, size, SUBHOOK_CODE_PROTECT_FLAGS);
+  int error = mprotect(address, size, SUBHOOK_CODE_PROTECT_FLAGS);
+#ifdef SUBHOOK_APPLE
+  if (-1 == error)
+    {
+        /* If mprotect fails, try to use VM_PROT_COPY with vm_protect. */
+        kern_return_t kret = vm_protect(mach_task_self(), (unsigned long)address, size, 0, SUBHOOK_CODE_PROTECT_FLAGS | VM_PROT_COPY);				
+        if (kret != KERN_SUCCESS)
+        {
+            error = -1;	
+        }
+        error = 0;
+    }				
+#endif
+  return error;
 }
 
 void *subhook_alloc_code(size_t size) {