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/*
* db_ndbm.c: low level ndbm interface routines for man.
*
* Copyright (C), 1994, 1995, Graeme W. Wilford. (Wilf.)
*
* You may distribute under the terms of the GNU Library General Public
* License as specified in the file COPYING.LIB that comes with this
* distribution.
*
* Mon Aug 8 20:35:30 BST 1994 Wilf. (G.Wilford@ee.surrey.ac.uk)
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif /* HAVE_CONFIG_H */
#ifdef NDBM
#include <stdio.h>
#if HAVE_SYS_FILE_H
# include <sys/file.h> /* for flock() */
#endif
#include <sys/types.h> /* for open() */
#include <sys/stat.h>
#if HAVE_FCNTL_H
# include <fcntl.h>
#endif
#ifdef STDC_HEADERS
#include <stdlib.h>
#endif /* STDC_HEADERS */
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif /* HAVE_UNISTD_H */
#include "manconfig.h"
#include "lib/flock.h"
#include "mydbm.h"
#include "db_storage.h"
/* release the lock and close the database */
int ndbm_flclose(DBM *dbf)
{
flock(dbm_dirfno(dbf), LOCK_UN);
dbm_close(dbf);
return 0;
}
/* open a ndbm type database, with file locking. */
DBM* ndbm_flopen(char *filename, int flags, int mode)
{
DBM *dbf;
int lock_op;
int lock_failed;
if (flags & ~O_RDONLY) {
/* flags includes O_RDWR or O_WRONLY, need an exclusive lock */
lock_op = LOCK_EX | LOCK_NB;
} else {
lock_op = LOCK_SH | LOCK_NB;
}
if (flags & O_TRUNC) {
/* opening the db is destructive, need to lock first */
char *dir_fname;
int dir_fd;
dbf = NULL;
lock_failed = 1;
dir_fname = xmalloc (strlen(filename) + 5);
sprintf (dir_fname, "%s.dir", filename);
dir_fd = open (dir_fname, flags & ~O_TRUNC, mode);
free(dir_fname);
if (dir_fd != -1) {
if (!(lock_failed = flock (dir_fd, lock_op)))
dbf = dbm_open(filename, flags, mode);
close (dir_fd);
}
} else {
dbf = dbm_open(filename, flags, mode);
if (dbf)
lock_failed = flock(dbm_dirfno(dbf), lock_op);
}
if (!dbf)
return NULL;
if (lock_failed) {
gripe_lock(filename);
dbm_close(dbf);
return NULL;
}
return dbf;
}
#endif /* NDBM */
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