1 files changed, 120 insertions, 0 deletions
diff --git a/src/backend/port/win32/shm.c b/src/backend/port/win32/shm.c
new file mode 100644
index 00000000000..20aaf1f6a4d
--- /dev/null
+++ b/src/backend/port/win32/shm.c
@@ -0,0 +1,120 @@
+/*-------------------------------------------------------------------------
+ *
+ * shm.c
+ *	  Microsoft Windows Win32 Shared Memory Emulation
+ *
+ * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+#include "windows.h"
+
+#include <stdio.h>
+#include <errno.h>
+
+static DWORD s_segsize = 0;
+
+/* Detach from a shared mem area based on its address */
+int
+shmdt(const void *shmaddr)
+{
+	if (UnmapViewOfFile(shmaddr))
+		return 0;
+	else
+		return -1;
+}
+
+/* Attach to an existing area */
+void *
+shmat(int memId, void* shmaddr, int flag)
+{
+	/* KEW_TODO -- shmat needs to count # attached to shared mem */
+	void *lpmem = MapViewOfFileEx((HANDLE)memId,
+			  FILE_MAP_WRITE | FILE_MAP_READ,
+			  0, 0, /* (DWORD)pshmdsc->segsize */ s_segsize, shmaddr);
+
+	if (lpmem == NULL) {
+		lpmem = (void *)-1;
+		errno = GetLastError();
+	}
+
+    return lpmem;
+}
+
+/* Control a shared mem area */
+int
+shmctl(int shmid, int flag, struct shmid_ds * dummy)
+{
+	if (flag == IPC_RMID)
+	{
+		/* Delete the area */
+		CloseHandle((HANDLE)shmid);
+		return 0;
+	}
+	if (flag == IPC_STAT)
+	{
+		/* Can only test for if exists */
+		int hmap = shmget(shmid, 0, 0);
+		if (hmap < 0) {
+			/* Shared memory does not exist */
+			errno = EINVAL;
+			return -1;
+		}
+		else {
+			/* Shared memory does exist and must be in use */
+			shmctl(hmap, IPC_RMID, NULL);	/* Release our hold on it */
+			errno = 0;
+			return 0;
+		}
+	}
+
+	errno = EINVAL;
+	return -1;
+}
+
+/* Get an area based on the IPC key */
+int
+shmget(int memKey, int size, int flag)
+{
+    HANDLE  hmap;
+	char szShareMem[32];
+	DWORD dwRet;
+
+    s_segsize = size;
+    sprintf(szShareMem, "sharemem.%d", memKey);
+
+	if (flag & IPC_CREAT) {
+		hmap = CreateFileMapping((HANDLE)0xFFFFFFFF,  /* Use the swap file    */
+					 NULL,
+					 PAGE_READWRITE,      /* Memory is Read/Write */
+					 0L,                  /* Size Upper 32 Bits   */
+					 (DWORD)s_segsize,      /* Size Lower 32 bits*/
+					 szShareMem);
+	}
+	else {
+		hmap = OpenFileMapping(FILE_MAP_ALL_ACCESS,
+								FALSE,
+								szShareMem);
+		if (!hmap) {
+			errno = ENOENT;
+			return -1;
+		}
+	}
+
+	dwRet = GetLastError();
+	if (dwRet == ERROR_ALREADY_EXISTS && hmap && (flag & (IPC_CREAT | IPC_EXCL))) {
+		/* Caller wanted to create the segment -- error if already exists */
+		CloseHandle(hmap);
+		errno = EEXIST;
+		return -1;
+	}
+	else if (!hmap)
+	{
+		/* Unable to get shared memory */
+		return -1;
+	}
+
+    return (int)hmap;
+}