mirror of https://github.com/postgres/postgres
Uses same underlying tech as before, but not the sysv emulation layer.REL8_3_STABLE
Magnus Hagander
19 years ago
parent
3b765dba78
commit
18d82d03b5
@ -1,128 +0,0 @@ |
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/*-------------------------------------------------------------------------
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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) 1996-2007, 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 1.14 2007/01/05 22:19:35 momjian 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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@ -0,0 +1,287 @@ |
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/*-------------------------------------------------------------------------
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* |
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* win32_shmem.c |
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* Implement shared memory using win32 facilities |
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* |
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* Portions Copyright (c) 1996-2007, 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 1.1 2007/03/21 14:39:23 mha Exp $ |
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* |
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*------------------------------------------------------------------------- |
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*/ |
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#include "postgres.h" |
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#include "miscadmin.h" |
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#include "storage/ipc.h" |
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#include "storage/pg_shmem.h" |
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unsigned long UsedShmemSegID = 0; |
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void *UsedShmemSegAddr = NULL; |
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static void pgwin32_SharedMemoryDelete(int status, Datum shmId); |
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/*
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* Generate shared memory segment name. Expand the data directory, to generate |
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* an identifier unique for this data directory. Then replace all backslashes |
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* with forward slashes, since backslashes aren't permitted in global object names. |
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* |
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* Store the shared memory segment in the Global\ namespace (requires NT2 TSE or |
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* 2000, but that's all we support for other reasons as well), to make sure you can't |
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* open two postmasters in different sessions against the same data directory. |
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* |
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* XXX: What happens with junctions? It's only someone breaking things on purpose, |
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* and this is still better than before, but we might want to do something about |
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* that sometime in the future. |
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*/ |
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static char * |
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GetSharedMemName(void) |
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{ |
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char *retptr; |
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DWORD bufsize; |
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DWORD r; |
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char *cp; |
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bufsize = GetFullPathName(DataDir, 0, NULL, NULL); |
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if (bufsize == 0) |
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elog(FATAL, "could not get size for full pathname of datadir %s: %lu", |
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DataDir, GetLastError()); |
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retptr = malloc(bufsize + 1 + 18); /* 1 NULL and 18 for
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* Global\PostgreSQL: */ |
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if (retptr == NULL) |
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elog(FATAL, "could not allocate memory for shared memory name"); |
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strcpy(retptr, "Global\\PostgreSQL:"); |
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r = GetFullPathName(DataDir, bufsize, retptr + 11, NULL); |
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if (r == 0 || r > bufsize) |
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elog(FATAL, "could not generate full pathname for datadir %s: %lu", |
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DataDir, GetLastError()); |
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for (cp = retptr; *cp; cp++) |
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if (*cp == '\\') |
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*cp = '/'; |
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return retptr; |
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} |
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/*
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* PGSharedMemoryIsInUse |
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* |
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* Is a previously-existing shmem segment still existing and in use? |
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* |
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* The point of this exercise is to detect the case where a prior postmaster |
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* crashed, but it left child backends that are still running. Therefore |
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* we only care about shmem segments that are associated with the intended |
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* DataDir. This is an important consideration since accidental matches of |
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* shmem segment IDs are reasonably common. |
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* |
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*/ |
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bool |
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PGSharedMemoryIsInUse(unsigned long id1, unsigned long id2) |
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{ |
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char *szShareMem; |
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HANDLE hmap; |
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szShareMem = GetSharedMemName(); |
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hmap = OpenFileMapping(FILE_MAP_READ, FALSE, szShareMem); |
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free(szShareMem); |
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if (hmap == NULL) |
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return false; |
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CloseHandle(hmap); |
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return true; |
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} |
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/*
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* PGSharedMemoryCreate |
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* |
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* Create a shared memory segment of the given size and initialize its |
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* standard header. |
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* |
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* makePrivate means to always create a new segment, rather than attach to |
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* or recycle any existing segment. On win32, we always create a new segment, |
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* since there is no need for recycling (segments go away automatically |
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* when the last backend exits) |
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* |
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*/ |
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PGShmemHeader * |
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PGSharedMemoryCreate(Size size, bool makePrivate, int port) |
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{ |
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void *memAddress; |
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PGShmemHeader *hdr; |
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HANDLE hmap, |
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hmap2; |
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char *szShareMem; |
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/* Room for a header? */ |
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Assert(size > MAXALIGN(sizeof(PGShmemHeader))); |
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szShareMem = GetSharedMemName(); |
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UsedShmemSegAddr = NULL; |
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hmap = CreateFileMapping((HANDLE) 0xFFFFFFFF, /* Use the pagefile */ |
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NULL, /* Default security attrs */ |
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PAGE_READWRITE, /* Memory is Read/Write */ |
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0L, /* Size Upper 32 Bits */ |
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(DWORD) size, /* Size Lower 32 bits */ |
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szShareMem); |
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if (!hmap) |
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ereport(FATAL, |
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(errmsg("could not create shared memory segment: %lu", GetLastError()), |
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errdetail("Failed system call was CreateFileMapping(size=%lu, name=%s)", size, szShareMem))); |
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/*
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* If the segment already existed, CreateFileMapping() will return a |
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* handle to the existing one. |
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*/ |
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if (GetLastError() == ERROR_ALREADY_EXISTS) |
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{ |
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/*
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* When recycling a shared memory segment, it may take a short while |
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* before it gets dropped from the global namespace. So re-try after |
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* sleeping for a second. |
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*/ |
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CloseHandle(hmap); /* Close the old handle, since we got a valid
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* one to the previous segment. */ |
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Sleep(1000); |
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hmap = CreateFileMapping((HANDLE) 0xFFFFFFFF, NULL, PAGE_READWRITE, 0L, (DWORD) size, szShareMem); |
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if (!hmap) |
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ereport(FATAL, |
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(errmsg("could not create shared memory segment: %lu", GetLastError()), |
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errdetail("Failed system call was CreateFileMapping(size=%lu, name=%s)", size, szShareMem))); |
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if (GetLastError() == ERROR_ALREADY_EXISTS) |
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ereport(FATAL, |
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(errmsg("pre-existing shared memory block is still in use"), |
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errhint("Check if there are any old server processes still running, and terminate them."))); |
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} |
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free(szShareMem); |
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/*
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* Make the handle inheritable |
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*/ |
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if (!DuplicateHandle(GetCurrentProcess(), hmap, GetCurrentProcess(), &hmap2, 0, TRUE, DUPLICATE_SAME_ACCESS)) |
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ereport(FATAL, |
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(errmsg("could not create shared memory segment: %lu", GetLastError()), |
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errdetail("Failed system call was DuplicateHandle"))); |
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/*
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* Close the old, non-inheritable handle. If this fails we don't really |
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* care. |
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*/ |
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if (!CloseHandle(hmap)) |
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elog(LOG, "could not close handle to shared memory: %lu", GetLastError()); |
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/* Register on-exit routine to delete the new segment */ |
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on_shmem_exit(pgwin32_SharedMemoryDelete, Int32GetDatum((unsigned long) hmap2)); |
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/*
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* Get a pointer to the new shared memory segment. Map the whole segment |
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* at once, and let the system decide on the initial address. |
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*/ |
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memAddress = MapViewOfFileEx(hmap2, FILE_MAP_WRITE | FILE_MAP_READ, 0, 0, 0, NULL); |
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if (!memAddress) |
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ereport(FATAL, |
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(errmsg("could not create shared memory segment: %lu", GetLastError()), |
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errdetail("Failed system call was MapViewOfFileEx"))); |
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/*
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* OK, we created a new segment. Mark it as created by this process. The |
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* order of assignments here is critical so that another Postgres process |
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* can't see the header as valid but belonging to an invalid PID! |
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*/ |
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hdr = (PGShmemHeader *) memAddress; |
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hdr->creatorPID = getpid(); |
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hdr->magic = PGShmemMagic; |
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/*
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* Initialize space allocation status for segment. |
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*/ |
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hdr->totalsize = size; |
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hdr->freeoffset = MAXALIGN(sizeof(PGShmemHeader)); |
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/* Save info for possible future use */ |
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UsedShmemSegAddr = memAddress; |
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UsedShmemSegID = (unsigned long) hmap2; |
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return hdr; |
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} |
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/*
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* PGSharedMemoryReAttach |
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* |
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* Re-attach to an already existing shared memory segment. Use the |
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* handle inherited from the postmaster. |
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* |
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* UsedShmemSegID and UsedShmemSegAddr are implicit parameters to this |
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* routine. The caller must have already restored them to the postmaster's |
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* values. |
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*/ |
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void |
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PGSharedMemoryReAttach(void) |
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{ |
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PGShmemHeader *hdr; |
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void *origUsedShmemSegAddr = UsedShmemSegAddr; |
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Assert(UsedShmemSegAddr != NULL); |
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Assert(IsUnderPostmaster); |
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hdr = (PGShmemHeader *) MapViewOfFileEx((HANDLE) UsedShmemSegID, FILE_MAP_READ | FILE_MAP_WRITE, 0, 0, 0, UsedShmemSegAddr); |
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if (!hdr) |
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elog(FATAL, "could not reattach to shared memory (key=%d, addr=%p): %lu", |
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(int) UsedShmemSegID, UsedShmemSegAddr, GetLastError()); |
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if (hdr != origUsedShmemSegAddr) |
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elog(FATAL, "reattaching to shared memory returned unexpected address (got %p, expected %p)", |
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hdr, origUsedShmemSegAddr); |
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if (hdr->magic != PGShmemMagic) |
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elog(FATAL, "reattaching to shared memory returned non-PostgreSQL memory"); |
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UsedShmemSegAddr = hdr; /* probably redundant */ |
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} |
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/*
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* PGSharedMemoryDetach |
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* |
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* Detach from the shared memory segment, if still attached. This is not |
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* intended for use by the process that originally created the segment. Rather, |
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* this is for subprocesses that have inherited an attachment and want to |
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* get rid of it. |
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*/ |
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void |
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PGSharedMemoryDetach(void) |
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{ |
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if (UsedShmemSegAddr != NULL) |
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{ |
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if (!UnmapViewOfFile(UsedShmemSegAddr)) |
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elog(LOG, "could not unmap view of shared memory: %lu", GetLastError()); |
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UsedShmemSegAddr = NULL; |
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} |
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} |
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/*
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* pgwin32_SharedMemoryDelete(status, shmId) deletes a shared memory segment |
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* (called as an on_shmem_exit callback, hence funny argument list) |
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*/ |
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static void |
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pgwin32_SharedMemoryDelete(int status, Datum shmId) |
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{ |
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PGSharedMemoryDetach(); |
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if (!CloseHandle((HANDLE) DatumGetInt32(shmId))) |
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elog(LOG, "could not close handle to shared memory: %lu", GetLastError()); |
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} |
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