[PATCH 0/1] MR4384: ntdll: Don't use sysconf(_SC_PHYS_PAGES) on macOS.

[Brendan Shanks (＠bshanks)]

`sysconf(_SC_PHYS_PAGES)` returns an error for i386 Mac binaries on any machine with more than 4 GB of RAM. From [the source code](https://github.com/apple-oss-distributions/Libc/blob/c5a3293354e22262702a3ad...) it's clear why--it calls `sysctlbyname()` to put the `hw.memsize` sysctl into a long, which is only 32-bits on i386. This returns an error on any Mac with more than 4GB: the value is too large for a 32-bit long.

The `sysctl` man page documents that an int64 should be used for `hw.memsize`, do that and divide by the page size ourselves.

[PATCH 1/1] ntdll: Don't use sysconf(_SC_PHYS_PAGES) on macOS.

[Brendan Shanks]

From: Brendan Shanks

---
 dlls/ntdll/unix/virtual.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/dlls/ntdll/unix/virtual.c b/dlls/ntdll/unix/virtual.c
index 464f343a575..75e6319c007 100644
--- a/dlls/ntdll/unix/virtual.c
+++ b/dlls/ntdll/unix/virtual.c
@@ -3329,6 +3329,15 @@ void virtual_get_system_info( SYSTEM_BASIC_INFORMATION *info, BOOL wow64 )
         ULONG64 total = (ULONG64)sinfo.totalram * sinfo.mem_unit;
         info->MmHighestPhysicalPage = max(1, total / page_size);
     }
+#elif defined(__APPLE__)
+    /* sysconf(_SC_PHYS_PAGES) is buggy on macOS: in a 32-bit process, it
+     * returns an error on Macs with >4GB of RAM.
+     */
+    INT64 memsize;
+    size_t len = sizeof(memsize);
+
+    if (!sysctlbyname( "hw.memsize", &memsize, &len, NULL, 0 ))
+        info->MmHighestPhysicalPage = max(1, memsize / page_size);
 #elif defined(_SC_PHYS_PAGES)
     LONG64 phys_pages = sysconf( _SC_PHYS_PAGES );