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57 lines
1.1 KiB
C
57 lines
1.1 KiB
C
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/*-
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* See the file LICENSE for redistribution information.
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*
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* Copyright (c) 1997-2005
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* Sleepycat Software. All rights reserved.
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*
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* $Id: os_flock.c,v 12.4 2005/06/20 14:59:01 bostic Exp $
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*/
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#include "db_config.h"
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#ifndef NO_SYSTEM_INCLUDES
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#include <sys/types.h>
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#include <fcntl.h>
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#include <string.h>
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#endif
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#include "db_int.h"
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/*
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* __os_fdlock --
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* Acquire/release a lock on a byte in a file.
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*
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* PUBLIC: int __os_fdlock __P((DB_ENV *, DB_FH *, off_t, int, int));
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*/
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int
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__os_fdlock(dbenv, fhp, offset, acquire, nowait)
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DB_ENV *dbenv;
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DB_FH *fhp;
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int acquire, nowait;
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off_t offset;
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{
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struct flock fl;
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int ret;
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DB_ASSERT(F_ISSET(fhp, DB_FH_OPENED) && fhp->fd != -1);
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#ifdef HAVE_FCNTL
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fl.l_start = offset;
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fl.l_len = 1;
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fl.l_type = acquire ? F_WRLCK : F_UNLCK;
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fl.l_whence = SEEK_SET;
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RETRY_CHK_EINTR_ONLY(
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(fcntl(fhp->fd, nowait ? F_SETLK : F_SETLKW, &fl)), ret);
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if (ret != 0 && ret != EACCES && ret != EAGAIN)
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__db_err(dbenv, "fcntl: %s", strerror(ret));
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return (ret);
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#else
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__db_err(dbenv,
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"advisory file locking unavailable: %s", strerror(DB_OPNOTSUP));
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return (DB_OPNOTSUP);
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#endif
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}
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