79 lines
2.4 KiB
C
79 lines
2.4 KiB
C
/* Copyright (C) 1979-1996 TcX AB & Monty Program KB & Detron HB
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This software is distributed with NO WARRANTY OF ANY KIND. No author or
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distributor accepts any responsibility for the consequences of using it, or
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for whether it serves any particular purpose or works at all, unless he or
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she says so in writing. Refer to the Free Public License (the "License")
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for full details.
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Every copy of this file must include a copy of the License, normally in a
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plain ASCII text file named PUBLIC. The License grants you the right to
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copy, modify and redistribute this file, but only under certain conditions
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described in the License. Among other things, the License requires that
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the copyright notice and this notice be preserved on all copies. */
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#ifdef __EMX__
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#include "../mysys/my_lock.c"
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#else
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#include <global.h>
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#include <my_sys.h>
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#include <mysys_err.h>
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#include <my_pthread.h>
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#include <thr_alarm.h>
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#include <errno.h>
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#ifdef HAVE_FCNTL
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static struct flock lock; /* Must be static for sun-sparc */
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#endif
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/* Lock a part of a file */
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int my_lock(File fd,int locktype,my_off_t start,my_off_t length,myf MyFlags)
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{
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thr_alarm_t alarmed;
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uint wait_for_alarm;
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DBUG_ENTER("my_lock");
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DBUG_PRINT("my",("Fd: %d Op: %d start: %ld Length: %ld MyFlags: %d",
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fd,locktype,(ulong) start,(ulong) length,MyFlags));
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if (my_disable_locking)
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DBUG_RETURN(0); /* purecov: inspected */
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lock.l_type=(short) locktype;
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lock.l_whence=0L;
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lock.l_start=(long) start;
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lock.l_len=(long) length;
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wait_for_alarm=(MyFlags & MY_DONT_WAIT ? MY_HOW_OFTEN_TO_ALARM :
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(uint) 12*60*60);
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if (fcntl(fd,F_SETLK,&lock) != -1) /* Check if we can lock */
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DBUG_RETURN(0); /* Ok, file locked */
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DBUG_PRINT("info",("Was locked, trying with alarm"));
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if (!thr_alarm(&alarmed,wait_for_alarm))
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{
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int value;
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while ((value=fcntl(fd,F_SETLKW,&lock)) && !thr_got_alarm(alarmed) &&
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errno == EINTR) ;
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thr_end_alarm(&alarmed);
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if (value != -1)
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DBUG_RETURN(0);
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}
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else
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{
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errno=EINTR;
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}
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if (errno == EINTR || errno == EACCES)
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my_errno=EAGAIN; /* Easier to check for this */
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else
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my_errno=errno;
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if (MyFlags & MY_WME)
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{
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if (locktype == F_UNLCK)
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my_error(EE_CANTUNLOCK,MYF(ME_BELL+ME_WAITTANG),errno);
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else
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my_error(EE_CANTLOCK,MYF(ME_BELL+ME_WAITTANG),errno);
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}
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DBUG_PRINT("error",("errno: %d",errno));
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DBUG_RETURN(-1);
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}
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#endif
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