[PATCH v11 4/4] ntdll: Keep pagemap file open after first use of NtQueryVirtualMemory(MemoryWorkingSetExInformation)

[Witold Baryluk]

From: Witold Baryluk

---
 dlls/ntdll/unix/virtual.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/dlls/ntdll/unix/virtual.c b/dlls/ntdll/unix/virtual.c
index 58afc87375c..0ade69441cb 100644
--- a/dlls/ntdll/unix/virtual.c
+++ b/dlls/ntdll/unix/virtual.c
@@ -4203,7 +4203,9 @@ static NTSTATUS get_working_set_ex( HANDLE process, LPCVOID addr,
                                     MEMORY_WORKING_SET_EX_INFORMATION *info,
                                     SIZE_T len, SIZE_T *res_len )
 {
-    int pagemap_fd;
+#if !defined(HAVE_LIBPROCSTAT)
+    static int pagemap_fd = -1;
+#endif
     MEMORY_WORKING_SET_EX_INFORMATION *p;
     sigset_t sigset;

@@ -4266,14 +4268,17 @@ static NTSTATUS get_working_set_ex( HANDLE process, LPCVOID addr,
             procstat_close( pstat );
     }
 #else
-    pagemap_fd = open( "/proc/self/pagemap", O_RDONLY, 0 );
+    server_enter_uninterrupted_section( &virtual_mutex, &sigset );
     if (pagemap_fd == -1)
     {
-        static int once;
-        if (!once++) WARN( "unable to open /proc/self/pagemap\n" );
+        pagemap_fd = open( "/proc/self/pagemap", O_RDONLY, 0 );
+        if (pagemap_fd == -1)
+        {
+            pagemap_fd = -2;
+            WARN( "unable to open /proc/self/pagemap\n" );
+        }
     }

-    server_enter_uninterrupted_section( &virtual_mutex, &sigset );
     for (p = info; (UINT_PTR)(p + 1) <= (UINT_PTR)info + len; p++)
     {
         BYTE vprot;
@@ -4286,7 +4291,7 @@ static NTSTATUS get_working_set_ex( HANDLE process, LPCVOID addr,
             get_committed_size( view, p->VirtualAddress, &vprot, VPROT_COMMITTED ) &&
             (vprot & VPROT_COMMITTED))
         {
-            if (pagemap_fd == -1 ||
+            if (pagemap_fd < 0 ||
                 pread( pagemap_fd, &pagemap, sizeof(pagemap), ((UINT_PTR)p->VirtualAddress >> page_shift) * sizeof(pagemap) ) != sizeof(pagemap))
             {
                 /* If we don't have pagemap information, default to invalid. */
@@ -4304,8 +4309,6 @@ static NTSTATUS get_working_set_ex( HANDLE process, LPCVOID addr,
     server_leave_uninterrupted_section( &virtual_mutex, &sigset );
 #endif

-    if (pagemap_fd != -1)
-        close( pagemap_fd );
     if (res_len)
         *res_len = (UINT_PTR)p - (UINT_PTR)info;
     return STATUS_SUCCESS;