free: implement sysinfo(2) and enable free(1)

This is an experimental implementation of sysinfo(2)/free(1).

It uses the WIN32 API GlobalMemoryStatusEx() to obtain information
about memory.

It seems that the 'total pagefile' value includes total RAM as well
as pagefile and 'available pagefile' includes available RAM.  So the
RAM values are deducted.

I've no idea what corresponds to Linux buffers and cache.

1 files changed, 24 insertions, 0 deletions

diff --git a/win32/mingw.c b/win32/mingw.c
index 75635fdf1..48d2eefa7 100644
--- a/win32/mingw.c
+++ b/win32/mingw.c
@@ -1368,6 +1368,30 @@ int mingw_unlink(const char *pathname)
         return ret;
 }
 
+int sysinfo(struct sysinfo *info)
+{
+        DECLARE_PROC_ADDR(BOOL, GlobalMemoryStatusEx, LPMEMORYSTATUSEX);
+        MEMORYSTATUSEX mem;
+
+        memset((void *)info, 0, sizeof(struct sysinfo));
+
+        if (!INIT_PROC_ADDR(kernel32.dll, GlobalMemoryStatusEx)) {
+                return -1;
+        }
+
+        mem.dwLength = sizeof(MEMORYSTATUSEX);
+        if (!GlobalMemoryStatusEx(&mem))
+                return -1;
+
+        info->mem_unit = 1;
+        info->totalram = mem.ullTotalPhys;
+        info->freeram = mem.ullAvailPhys;
+        info->totalswap = mem.ullTotalPageFile - mem.ullTotalPhys;
+        info->freeswap = mem.ullAvailPageFile - mem.ullAvailPhys;
+
+        return 0;
+}
+
 #undef strftime
 size_t mingw_strftime(char *buf, size_t max, const char *format, const struct tm *tm)
 {