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/*
* LIB/LOCK.C
*
* (c)Copyright 1997, Matthew Dillon, All Rights Reserved. Refer to
* the COPYRIGHT file in the base directory of this distribution
* for specific rights granted.
*/
#include "defs.h"
Prototype int xflock(int fd, int flags);
Prototype int hflock(int fd, int offset, int flags);
/*
* xflock() - a global lock.
*
* NOTE: cannot be used in conjuction with hflock() due to odd overlap
* interaction. If we create other locks, they may wind up sticking
* around while the unlocks take holes out of the original.
*/
int
xflock(int fd, int flags)
{
int r;
struct flock fl = { 0 };
fl.l_whence = SEEK_SET;
switch(flags & 0x0F) {
case XLOCK_SH:
fl.l_type = F_RDLCK;
break;
case XLOCK_EX:
fl.l_type = F_WRLCK;
break;
case XLOCK_UN:
fl.l_type = F_UNLCK;
break;
}
r = fcntl(fd, ((flags & XLOCK_NB) ? F_SETLK : F_SETLKW), &fl);
return(r);
}
int
hflock(int fd, int offset, int flags)
{
int r;
struct flock fl = { 0 };
switch(flags & 0x0F) {
case XLOCK_SH:
fl.l_type = F_RDLCK;
break;
case XLOCK_EX:
fl.l_type = F_WRLCK;
break;
case XLOCK_UN:
fl.l_type = F_UNLCK;
break;
}
fl.l_whence = SEEK_SET;
fl.l_start = offset;
fl.l_len = 4;
r = fcntl(fd, ((flags & XLOCK_NB) ? F_SETLK : F_SETLKW), &fl);
return(r);
}
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