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ae643747b1
have no other gods before c.h'. Also remove some demonstrably redundant #include lines, mostly of <errno.h> which was added to c.h years ago.
129 lines
2.6 KiB
C
129 lines
2.6 KiB
C
/*-------------------------------------------------------------------------
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*
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* shmem.c
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* Microsoft Windows Win32 Shared Memory Emulation
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*
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* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/port/win32/shmem.c,v 1.13 2006/07/14 05:28:28 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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static DWORD s_segsize = 0;
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/* Detach from a shared mem area based on its address */
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int
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shmdt(const void *shmaddr)
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{
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if (UnmapViewOfFile((LPCVOID *) shmaddr))
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return 0;
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else
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return -1;
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}
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/* Attach to an existing area */
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void *
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shmat(int memId, void *shmaddr, int flag)
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{
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/* TODO -- shmat needs to count # attached to shared mem */
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void *lpmem = MapViewOfFileEx((HANDLE) memId,
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FILE_MAP_WRITE | FILE_MAP_READ,
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0, 0, /* (DWORD)pshmdsc->segsize */ 0 /* s_segsize */ , shmaddr);
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if (lpmem == NULL)
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{
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lpmem = (void *) -1;
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_dosmaperr(GetLastError());
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}
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return lpmem;
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}
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/* Control a shared mem area */
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int
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shmctl(int shmid, int flag, struct shmid_ds * dummy)
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{
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if (flag == IPC_RMID)
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{
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/* Delete the area */
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CloseHandle((HANDLE) shmid);
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return 0;
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}
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if (flag == IPC_STAT)
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{
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/* Can only test for if exists */
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int hmap = shmget(shmid, 0, 0);
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if (hmap < 0)
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{
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/* Shared memory does not exist */
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errno = EINVAL;
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return -1;
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}
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else
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{
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/* Shared memory does exist and must be in use */
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shmctl(hmap, IPC_RMID, NULL); /* Release our hold on it */
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errno = 0;
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return 0;
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}
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}
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errno = EINVAL;
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return -1;
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}
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/* Get an area based on the IPC key */
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int
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shmget(int memKey, int size, int flag)
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{
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HANDLE hmap;
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char szShareMem[32];
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DWORD dwRet;
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s_segsize = size;
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sprintf(szShareMem, "PostgreSQL.%d", memKey);
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if (flag & IPC_CREAT)
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{
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hmap = CreateFileMapping((HANDLE) 0xFFFFFFFF, /* Use the swap file */
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NULL,
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PAGE_READWRITE, /* Memory is Read/Write */
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0L, /* Size Upper 32 Bits */
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(DWORD) s_segsize, /* Size Lower 32 bits */
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szShareMem);
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}
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else
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{
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hmap = OpenFileMapping(FILE_MAP_ALL_ACCESS,
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FALSE,
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szShareMem);
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if (!hmap)
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{
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errno = ENOENT;
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return -1;
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}
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}
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dwRet = GetLastError();
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if (dwRet == ERROR_ALREADY_EXISTS && hmap && (flag & (IPC_CREAT | IPC_EXCL)))
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{
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/* Caller wanted to create the segment -- error if already exists */
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CloseHandle(hmap);
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errno = EEXIST;
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return -1;
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}
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else if (!hmap)
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{
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/* Unable to get shared memory */
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_dosmaperr(GetLastError());
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return -1;
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}
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return (int) hmap;
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}
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