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# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
include <config.h>
include "mtio.h"
# MT_READ_LOCKFILE -- Read the magtape lock file to determine the current
# position of the tape (the lock file is used to record the tape position
# while the device is closed). If the lock file cannot be accessed or an
# error occurs in reading it, return an undefined tape position.
procedure mt_read_lockfile (mtname, mt)
char mtname[ARB] #I device name
int mt #I MTIO descriptor
int fd, ip
pointer sp, lockfile, lbuf
int strmatch(), stridxs(), ctoi(), open(), getline()
errchk open, getline
include "mtio.com"
define err_ 91
begin
call smark (sp)
call salloc (lockfile, SZ_FNAME, TY_CHAR)
call salloc (lbuf, SZ_LINE, TY_CHAR)
# If the lock file cannot be accessed, return an undefined tape
# position but do not abort.
#call mt_lockname (MT_LKNAME(mt), Memc[lockfile], SZ_FNAME)
call strcpy (MT_LKNAME(mt), Memc[lockfile], SZ_FNAME)
iferr (fd = open (Memc[lockfile], READ_ONLY, TEXT_FILE)) {
fd = ERR
goto err_
}
# Get file number.
repeat {
if (getline (fd, Memc[lbuf]) == EOF)
goto err_
} until (strmatch (Memc[lbuf], "^file") > 0)
ip = stridxs ("=", Memc[lbuf]) + 1
if (ctoi (Memc[lbuf], ip, MT_FILNO(mt)) == 0)
goto err_
# Get record number.
if (getline (fd, Memc[lbuf]) == EOF)
goto err_
ip = stridxs ("=", Memc[lbuf]) + 1
if (ctoi (Memc[lbuf], ip, MT_RECNO(mt)) == 0)
goto err_
# Get total files on tape.
if (getline (fd, Memc[lbuf]) == EOF)
goto err_
ip = stridxs ("=", Memc[lbuf]) + 1
if (ctoi (Memc[lbuf], ip, MT_NFILES(mt)) == 0)
goto err_
# Get amount of tape used.
if (getline (fd, Memc[lbuf]) == EOF)
goto err_
ip = stridxs ("=", Memc[lbuf]) + 1
if (ctoi (Memc[lbuf], ip, MT_TAPEUSED(mt)) == 0)
goto err_
# Get pflags.
if (getline (fd, Memc[lbuf]) == EOF)
goto err_
ip = stridxs ("=", Memc[lbuf]) + 1
if (ctoi (Memc[lbuf], ip, MT_PFLAGS(mt)) == 0)
goto err_
call close (fd)
call sfree (sp)
return
err_
if (fd != ERR)
call close (fd)
# Write a new lock file so that we can update the tape position
# later (the file must exist after the drive is opened).
call mtallocate (mtname)
# Return an undefined tape position.
MT_FILNO(mt) = -1
MT_RECNO(mt) = -1
call sfree (sp)
end
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