win32: update sysinfo(2) implementation (again)

Use another API call:  EnumPageFiles().  This seems to provide more
reliable information about page file usage than the previous ad hoc
method.  It also allows the call to GlobalMemoryStatusEx() to be
removed.

With these changes free(1) works sensibly on Windows XP, though not
ReactOS.

1 files changed, 31 insertions, 14 deletions

diff --git a/win32/mingw.c b/win32/mingw.c
index 73179dac9..b01198bd2 100644
--- a/win32/mingw.c
+++ b/win32/mingw.c
@@ -1369,15 +1369,33 @@ int mingw_unlink(const char *pathname)
         return ret;
 }
 
+struct pagefile_info {
+        SIZE_T total;
+        SIZE_T in_use;
+};
+
+static BOOL CALLBACK
+pagefile_cb(LPVOID context, PENUM_PAGE_FILE_INFORMATION info,
+                                LPCSTR name UNUSED_PARAM)
+{
+        struct pagefile_info *pfinfo = (struct pagefile_info *)context;
+
+        pfinfo->total += info->TotalSize;
+        pfinfo->in_use += info->TotalInUse;
+        return TRUE;
+}
+
 int sysinfo(struct sysinfo *info)
 {
-        DECLARE_PROC_ADDR(BOOL, GlobalMemoryStatusEx, LPMEMORYSTATUSEX);
-        DECLARE_PROC_ADDR(BOOL, GetPerformanceInfo, PPERFORMANCE_INFORMATION, DWORD);
-        MEMORYSTATUSEX mem;
         PERFORMANCE_INFORMATION perf;
+        struct pagefile_info pfinfo;
+        DECLARE_PROC_ADDR(BOOL, GetPerformanceInfo, PPERFORMANCE_INFORMATION,
+                                                DWORD);
+        DECLARE_PROC_ADDR(BOOL, EnumPageFilesA, PENUM_PAGE_FILE_CALLBACKA, LPVOID);
 
         memset((void *)info, 0, sizeof(struct sysinfo));
         memset((void *)&perf, 0, sizeof(PERFORMANCE_INFORMATION));
+        memset((void *)&pfinfo, 0, sizeof(struct pagefile_info));
         info->mem_unit = 4096;
 
         if (INIT_PROC_ADDR(psapi.dll, GetPerformanceInfo)) {
@@ -1385,19 +1403,18 @@ int sysinfo(struct sysinfo *info)
                 GetPerformanceInfo(&perf, perf.cb);
         }
 
-        if (INIT_PROC_ADDR(kernel32.dll, GlobalMemoryStatusEx)) {
-                mem.dwLength = sizeof(MEMORYSTATUSEX);
-                if (GlobalMemoryStatusEx(&mem)) {
-                        info->totalram = mem.ullTotalPhys >> 12;
-                        info->bufferram = (perf.SystemCache * perf.PageSize) >> 12;
-                        if ((mem.ullAvailPhys >> 12) > info->bufferram)
-                                info->freeram = (mem.ullAvailPhys >> 12) - info->bufferram;
-                        info->totalswap = (mem.ullTotalPageFile - mem.ullTotalPhys) >> 12;
-                        if (mem.ullAvailPageFile > mem.ullAvailPhys)
-                                info->freeswap = (mem.ullAvailPageFile-mem.ullAvailPhys) >> 12;
-                }
+        if (INIT_PROC_ADDR(psapi.dll, EnumPageFilesA)) {
+                EnumPageFilesA((PENUM_PAGE_FILE_CALLBACK)pagefile_cb, (LPVOID)&pfinfo);
         }
 
+        info->totalram = perf.PhysicalTotal * perf.PageSize / 4096;
+        info->bufferram = perf.SystemCache * perf.PageSize / 4096;
+        if (perf.PhysicalAvailable > perf.SystemCache)
+                info->freeram = perf.PhysicalAvailable * perf.PageSize / 4096 -
+                                                        info->bufferram;
+        info->totalswap = pfinfo.total * perf.PageSize / 4096;
+        info->freeswap = (pfinfo.total - pfinfo.in_use) * perf.PageSize / 4096;
+
         info->uptime = GetTickCount64() / 1000;
         info->procs = perf.ProcessCount;