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135 lines
2.5 KiB
C
135 lines
2.5 KiB
C
/*
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* Copyright (c) 1996 Regents of the University of Michigan.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms are permitted
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* provided that this notice is preserved and that due credit is given
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* to the University of Michigan at Ann Arbor. The name of the University
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* may not be used to endorse or promote products derived from this
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* software without specific prior written permission. This software
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* is provided ``as is'' without express or implied warranty.
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*/
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/*
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* lock.c - routines to open and apply an advisory lock to a file
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*/
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#include <stdio.h>
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#include <sys/time.h>
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#include <sys/types.h>
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#include <sys/file.h>
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#include <sys/param.h>
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#include <sys/socket.h>
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#include "portable.h"
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#ifdef USE_LOCKF
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#include <unistd.h>
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#endif
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#include "../slapd/slap.h"
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FILE *
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lock_fopen(
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char *fname,
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char *type,
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FILE **lfp
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)
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{
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FILE *fp;
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char buf[MAXPATHLEN];
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/* open the lock file */
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strcpy( buf, fname );
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strcat( buf, ".lock" );
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if ( (*lfp = fopen( buf, "w" )) == NULL ) {
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Debug( LDAP_DEBUG_ANY,
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"Error: could not open \"%s\"\n", buf, 0, 0 );
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return( NULL );
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}
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/* acquire the lock */
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#ifdef USE_LOCKF
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while ( lockf( fileno( *lfp ), F_LOCK, 0 ) != 0 ) {
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#else
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while ( flock( fileno( *lfp ), LOCK_EX ) != 0 ) {
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#endif
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; /* NULL */
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}
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/* open the log file */
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if ( (fp = fopen( fname, type )) == NULL ) {
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Debug( LDAP_DEBUG_ANY,
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"Error: could not open \"%s\"\n", fname, 0, 0 );
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#ifdef USE_LOCKF
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lockf( fileno( *lfp ), F_ULOCK, 0 );
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#else
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flock( fileno( *lfp ), LOCK_UN );
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#endif
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return( NULL );
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}
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return( fp );
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}
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int
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lock_fclose(
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FILE *fp,
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FILE *lfp
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)
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{
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/* unlock */
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#ifdef USE_LOCKF
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lockf( fileno( lfp ), F_ULOCK, 0 );
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#else
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flock( fileno( lfp ), LOCK_UN );
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#endif
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fclose( lfp );
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return( fclose( fp ) );
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}
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/*
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* Apply an advisory lock on a file. Just calls lock_fopen()
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*/
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int
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acquire_lock(
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char *file,
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FILE **rfp,
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FILE **lfp
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)
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{
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if (( *rfp = lock_fopen( file, "r+", lfp )) == NULL ) {
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Debug( LDAP_DEBUG_ANY,
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"Error: acquire_lock(%d): Could not acquire lock on \"%s\"\n",
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getpid(), file, 0);
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return( -1 );
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}
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return( 0 );
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}
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/*
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* Relinquish a lock on a file. Calls lock_fclose() and also removes the
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* lock file.
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*/
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int
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relinquish_lock(
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char *file,
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FILE *rfp,
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FILE *lfp
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)
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{
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if ( lock_fclose( rfp, lfp ) == EOF ) {
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Debug( LDAP_DEBUG_ANY,
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"Error: relinquish_lock (%d): Error closing \"%s\"\n",
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getpid(), file, 0 );
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return( -1 );
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}
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return( 0 );
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}
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