* Copyright (c) 1980 Regents of the University of California.
* All rights reserved. The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
static char sccsid
[] = "@(#)tape.c 5.8 (Berkeley) %G%";
char (*tblock
)[TP_BSIZE
]; /* pointer to malloc()ed buffer for tape */
int writesize
; /* size of malloc()ed buffer for tape */
long lastspclrec
= -1; /* tape block number of last written header */
int trecno
= 0; /* next record to write in current block */
extern int ntrec
; /* blocking factor on tape */
extern int read(), write();
* Concurrent dump mods (Caltech) - disk block reading and tape writing
* are exported to several slave processes. While one slave writes the
* tape, the others read disk blocks; they pass control of the tape in
* a ring via flock(). The parent process traverses the filesystem and
* sends spclrec()'s and lists of daddr's to the slaves via pipes.
struct req
{ /* instruction packets sent to slaves */
#define SLAVES 3 /* 1 slave writing, 1 reading, 1 for slack */
int slavefd
[SLAVES
]; /* pipes from master to each slave */
int slavepid
[SLAVES
]; /* used by killall() */
int rotor
; /* next slave to be instructed */
int master
; /* pid of master, for sending error signals */
int tenths
; /* length of tape used per block written */
int pgoff
= getpagesize() - 1;
writesize
= ntrec
* TP_BSIZE
;
reqsiz
= ntrec
* sizeof(struct req
);
* CDC 92181's and 92185's make 0.8" gaps in 1600-bpi start/stop mode
* (see DEC TU80 User's Guide). The shorter gaps of 6250-bpi require
* repositioning after stopping, i.e, streaming mode, where the gap is
* variable, 0.30" to 0.45". The gap is maximal when the tape stops.
tenths
= writesize
/density
+ (cartridge
? 16 : density
== 625 ? 5 : 8);
* Allocate tape buffer contiguous with the array of instruction
* packets, so flusht() can write them together with one write().
* Align tape buffer on page boundary to speed up tape write().
req
= (struct req
*)malloc(reqsiz
+ writesize
+ pgoff
);
tblock
= (char (*)[TP_BSIZE
]) (((long)&req
[ntrec
] + pgoff
) &~ pgoff
);
req
= (struct req
*)tblock
- ntrec
;
req
[trecno
].dblk
= (daddr_t
)0;
*(union u_spcl
*)(*tblock
++) = *(union u_spcl
*)dp
; /* movc3 */
lastspclrec
= spcl
.c_tapea
;
int avail
, tpblks
, dblkno
;
dblkno
= fsbtodb(sblock
, blkno
);
tpblks
= size
/ TP_BSIZE
;
while ((avail
= MIN(tpblks
, ntrec
- trecno
)) > 0) {
req
[trecno
].dblk
= dblkno
;
req
[trecno
].count
= avail
;
dblkno
+= avail
* (TP_BSIZE
/ dev_bsize
);
msg("Tape write error on %s\n", tape
);
msg("Tape write error %d feet into tape %d\n", asize
/120L, tapeno
);
broadcast("TAPE ERROR!\n");
if (!query("Do you want to restart?"))
msg("This tape will rewind. After it is rewound,\n");
msg("replace the faulty tape with a new one;\n");
msg("this dump volume will be rewritten.\n");
for (i
= 0; i
< ntrec
; i
++)
int siz
= (char *)tblock
- (char *)req
;
if (atomic(write
, slavefd
[rotor
], req
, siz
) != siz
) {
perror(" DUMP: error writing command pipe");
if (++rotor
>= SLAVES
) rotor
= 0;
tblock
= (char (*)[TP_BSIZE
]) &req
[ntrec
];
if (!pipeout
&& asize
> tsize
) {
for (f
= 0; f
< SLAVES
; f
++)
while (wait(NULL
) >= 0) ; /* wait for any signals from slaves */
while (rmtopen(tape
, 0) < 0)
while ((f
= open(tape
, 0)) < 0)
msg("Change Tapes: Mount tape #%d\n", tapeno
+1);
broadcast("CHANGE TAPES!\7\7\n");
while (!query("Is the new tape mounted and ready to go?"))
if (query("Do you want to abort?")) {
* We implement taking and restoring checkpoints on the tape level.
* When each tape is opened, a new process is created by forking; this
* saves all of the necessary context in the parent. The child
* continues the dump; the parent waits around, saving the context.
* If the child returns X_REWRITE, then it had problems writing that tape;
* this causes the parent to fork again, duplicating the context, and
* everything continues as if nothing had happened.
int (*interrupt
)() = signal(SIGINT
, SIG_IGN
);
signal(SIGINT
, interrupt
);
* All signals are inherited...
msg("Context save fork fails in parent %d\n", parentpid
);
* save the context by waiting
* until the child doing all of the work returns.
* don't catch the interrupt
msg("Tape: %d; parent process: %d child process %d\n",
tapeno
+1, parentpid
, childpid
);
while ((waitpid
= wait(&status
)) != childpid
)
msg("Parent %d waiting for child %d has another child %d return\n",
parentpid
, childpid
, waitpid
);
msg("Child %d returns LOB status %o\n",
status
= (status
>> 8) & 0xFF;
msg("Child %d finishes X_FINOK\n", childpid
);
msg("Child %d finishes X_ABORT\n", childpid
);
msg("Child %d finishes X_REWRITE\n", childpid
);
msg("Child %d finishes unknown %d\n",
goto restore_check_point
;
msg("Bad return code from dump: %d\n", status
);
} else { /* we are the child; just continue */
sleep(4); /* allow time for parent's message to get out */
msg("Child on Tape %d has parent %d, my pid = %d\n",
tapeno
+1, parentpid
, getpid());
while ((to
= (host
? rmtopen(tape
, 2) :
pipeout
? 1 : creat(tape
, 0666))) < 0)
while ((to
= pipeout
? 1 : creat(tape
, 0666)) < 0)
if (!query("Cannot open tape. Do you want to retry the open?"))
enslave(); /* Share open tape file descriptor with slaves */
tapeno
++; /* current tape sequence */
newtape
++; /* new tape signal */
if (spcl
.c_type
!= TS_END
)
for (i
= 0; i
< spcl
.c_count
; i
++)
spcl
.c_count
= blks
+ 1 - spcl
.c_tapea
+ lastspclrec
;
spcl
.c_flags
|= DR_NEWHEADER
;
spcl
.c_flags
&=~ DR_NEWHEADER
;
msg("Tape %d begins with blocks from ino %d\n",
if (master
!= 0 && master
!= getpid())
kill(master
, SIGTERM
); /* Signals master to call dumpabort */
msg("The ENTIRE dump is aborted.\n");
msg("pid = %d exits with status %d\n", getpid(), status
);
* could use pipe() for this if flock() worked on pipes
strcpy(tmpname
, "/tmp/dumplockXXXXXX");
if ((fd
[1] = creat(tmpname
, 0400)) < 0) {
msg("Could not create lockfile ");
if ((fd
[0] = open(tmpname
, 0)) < 0) {
msg("Could not reopen lockfile ");
int first
[2], prev
[2], next
[2], cmd
[2]; /* file descriptors */
signal(SIGTERM
, dumpabort
); /* Slave sends SIGTERM on dumpabort() */
signal(SIGPIPE
, sigpipe
);
signal(SIGUSR1
, tperror
); /* Slave sends SIGUSR1 on tape errors */
for (i
= 0; i
< SLAVES
; i
++) {
next
[1] = first
[1]; /* Last slave loops back */
if (pipe(cmd
) < 0 || (slavepid
[i
] = fork()) < 0) {
msg("too many slaves, %d (recompile smaller) ", i
);
if (slavepid
[i
] == 0) { /* Slave starts up here */
signal(SIGINT
, SIG_IGN
); /* Master handles this */
doslave(cmd
[0], prev
, next
);
for (i
= 0; i
< SLAVES
; i
++)
kill(slavepid
[i
], SIGKILL
);
* Synchronization - each process has a lockfile, and shares file
* descriptors to the following process's lockfile. When our write
* completes, we release our lock on the following process's lock-
* file, allowing the following process to lock it and proceed. We
* get the lock back for the next cycle by swapping descriptors.
register int cmd
, prev
[2], next
[2];
register int nread
, toggle
= 0;
if ((fi
= open(disk
, 0)) < 0) { /* Need our own seek pointer */
perror(" DUMP: slave couldn't reopen disk");
* Get list of blocks to dump, read the blocks into tape buffer
while ((nread
= atomic(read
, cmd
, req
, reqsiz
)) == reqsiz
) {
register struct req
*p
= req
;
for (trecno
= 0; trecno
< ntrec
; trecno
+= p
->count
, p
+= p
->count
) {
bread(p
->dblk
, tblock
[trecno
],
if (p
->count
!= 1 || atomic(read
, cmd
,
tblock
[trecno
], TP_BSIZE
) != TP_BSIZE
) {
msg("Master/slave protocol botched.\n");
flock(prev
[toggle
], LOCK_EX
); /* Wait our turn */
if ((host
? rmtwrite(tblock
[0], writesize
)
: write(to
, tblock
[0], writesize
)) != writesize
) {
if (write(to
, tblock
[0], writesize
) != writesize
) {
flock(next
[toggle
], LOCK_UN
); /* Next slave's turn */
} /* Also jolts him awake */
perror(" DUMP: error reading command pipe");
* Since a read from a pipe may not return all we asked for,
* or a write may not write all we ask if we get a signal,
* loop until the count is satisfied (or error).
atomic(func
, fd
, buf
, count
)
int (*func
)(), fd
, count
;
while ((got
= (*func
)(fd
, buf
, need
)) > 0 && (need
-= got
) > 0)
return (got
< 0 ? got
: count
- need
);