1 files changed, 93 insertions, 0 deletions
diff --git a/sys/mtio/mtrdlock.x b/sys/mtio/mtrdlock.x
new file mode 100644
index 00000000..774fab19
--- /dev/null
+++ b/sys/mtio/mtrdlock.x
@@ -0,0 +1,93 @@
+# 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