63 lines
1.4 KiB
C
63 lines
1.4 KiB
C
/*-
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* See the file LICENSE for redistribution information.
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*
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* Copyright (c) 1997,2008 Oracle. All rights reserved.
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*
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* $Id: os_flock.c 63573 2008-05-23 21:43:21Z trent.nelson $
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*/
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#include "db_config.h"
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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((ENV *, DB_FH *, off_t, int, int));
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*/
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int
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__os_fdlock(env, fhp, offset, acquire, nowait)
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ENV *env;
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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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#ifdef HAVE_FCNTL
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DB_ENV *dbenv;
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struct flock fl;
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int ret, t_ret;
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dbenv = env == NULL ? NULL : env->dbenv;
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DB_ASSERT(env, F_ISSET(fhp, DB_FH_OPENED) && fhp->fd != -1);
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if (dbenv != NULL && FLD_ISSET(dbenv->verbose, DB_VERB_FILEOPS_ALL))
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__db_msg(env,
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"fileops: flock %s %s offset %lu",
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fhp->name, acquire ? "acquire": "release", (u_long)offset);
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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)
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return (0);
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if ((t_ret = __os_posix_err(ret)) != EACCES && t_ret != EAGAIN)
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__db_syserr(env, ret, "fcntl");
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return (t_ret);
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#else
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COMPQUIET(fhp, NULL);
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COMPQUIET(acquire, 0);
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COMPQUIET(nowait, 0);
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COMPQUIET(offset, 0);
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__db_syserr(env, DB_OPNOTSUP, "advisory file locking unavailable");
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return (DB_OPNOTSUP);
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#endif
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}
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