]>
git.wh0rd.org - dump.git/blob - dump/tape.c
45828a52f742e782b48582be691317487a9e8070
2 * Ported to Linux's Second Extended File System as part of the
3 * dump and restore backup suit
4 * Remy Card <card@Linux.EU.Org>, 1994-1997
5 * Stelian Pop <pop@cybercable.fr>, 1999-2000
9 * Copyright (c) 1980, 1991, 1993
10 * The Regents of the University of California. All rights reserved.
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. All advertising materials mentioning features or use of this software
21 * must display the following acknowledgement:
22 * This product includes software developed by the University of
23 * California, Berkeley and its contributors.
24 * 4. Neither the name of the University nor the names of its contributors
25 * may be used to endorse or promote products derived from this software
26 * without specific prior written permission.
28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
42 static const char rcsid
[] =
43 "$Id: tape.c,v 1.17 2000/03/10 10:03:09 stelian Exp $";
47 #include <sys/types.h>
48 #include <linux/types.h>
50 #include <sys/param.h>
51 #include <sys/socket.h>
55 #include <linux/ext2_fs.h>
56 #include <bsdcompat.h>
59 #include <sys/vnode.h>
62 #include <ufs/inode.h>
64 #include <ufs/ufs/dinode.h>
65 #include <ufs/ffs/fs.h>
67 #endif /* __linux__ */
69 #include <protocols/dumprestore.h>
76 #include <compaterr.h>
86 #include <ext2fs/ext2fs.h>
91 int writesize
; /* size of malloc()ed buffer for tape */
92 long lastspclrec
= -1; /* tape block number of last written header */
93 int trecno
= 0; /* next record to write in current block */
94 extern long blocksperfile
; /* number of blocks per output file */
95 long blocksthisvol
; /* number of blocks on current output file */
96 extern int ntrec
; /* blocking factor on tape */
103 static ssize_t atomic_read
__P((int, void *, size_t));
104 static ssize_t atomic_write
__P((int, const void *, size_t));
105 static void doslave
__P((int, int));
106 static void enslave
__P((void));
107 static void flushtape
__P((void));
108 static void killall
__P((void));
109 static void rollforward
__P((void));
110 static int system_command
__P((const char *, const char *, int));
113 * Concurrent dump mods (Caltech) - disk block reading and tape writing
114 * are exported to several slave processes. While one slave writes the
115 * tape, the others read disk blocks; they pass control of the tape in
116 * a ring via signals. The parent process traverses the filesystem and
117 * sends writeheader()'s and lists of daddr's to the slaves via pipes.
118 * The following structure defines the instruction packets sent to slaves.
126 #define SLAVES 3 /* 1 slave writing, 1 reading, 1 for slack */
128 int tapea
; /* header number at start of this chunk */
129 int count
; /* count to next header (used for TS_TAPE */
131 int inode
; /* inode that we are currently dealing with */
132 int fd
; /* FD for this slave */
133 int pid
; /* PID for this slave */
134 int sent
; /* 1 == we've sent this slave requests */
135 int firstrec
; /* record number of this block */
136 char (*tblock
)[TP_BSIZE
]; /* buffer for data blocks */
137 struct req
*req
; /* buffer for requests */
141 char (*nextblock
)[TP_BSIZE
];
143 static time_t tstart_volume
; /* time of volume start */
144 static int tapea_volume
; /* value of spcl.c_tapea at volume start */
146 int master
; /* pid of master, for sending error signals */
147 int tenths
; /* length of tape used per block written */
148 static int caught
; /* have we caught the signal to proceed? */
149 static int ready
; /* have we reached the lock point without having */
150 /* received the SIGUSR2 signal from the prev slave? */
151 static sigjmp_buf jmpbuf
; /* where to jump to if we are ready when the */
152 /* SIGUSR2 arrives from the previous slave */
157 int pgoff
= getpagesize() - 1;
161 writesize
= ntrec
* TP_BSIZE
;
162 reqsiz
= (ntrec
+ 1) * sizeof(struct req
);
164 * CDC 92181's and 92185's make 0.8" gaps in 1600-bpi start/stop mode
165 * (see DEC TU80 User's Guide). The shorter gaps of 6250-bpi require
166 * repositioning after stopping, i.e, streaming mode, where the gap is
167 * variable, 0.30" to 0.45". The gap is maximal when the tape stops.
169 if (blocksperfile
== 0 && !unlimited
)
170 tenths
= writesize
/ density
+
171 (cartridge
? 16 : density
== 625 ? 5 : 8);
173 * Allocate tape buffer contiguous with the array of instruction
174 * packets, so flushtape() can write them together with one write().
175 * Align tape buffer on page boundary to speed up tape write().
177 for (i
= 0; i
<= SLAVES
; i
++) {
179 malloc((unsigned)(reqsiz
+ writesize
+ pgoff
+ TP_BSIZE
));
182 slaves
[i
].tblock
= (char (*)[TP_BSIZE
])
184 (((long)&buf
[reqsiz
] + pgoff
) &~ pgoff
);
186 (((long)&buf
[ntrec
+ 1] + pgoff
) &~ pgoff
);
188 slaves
[i
].req
= (struct req
*)slaves
[i
].tblock
- ntrec
- 1;
194 nextblock
= slp
->tblock
;
199 writerec(const void *dp
, int isspcl
)
202 slp
->req
[trecno
].dblk
= (daddr_t
)0;
203 slp
->req
[trecno
].count
= 1;
204 /* XXX post increment triggers an egcs-1.1.2-12 bug on alpha/sparc */
205 *(union u_spcl
*)(*(nextblock
)) = *(union u_spcl
*)dp
;
208 lastspclrec
= spcl
.c_tapea
;
216 dumpblock(daddr_t blkno
, int size
)
218 int avail
, tpblks
, dblkno
;
220 dblkno
= fsbtodb(sblock
, blkno
);
221 tpblks
= size
>> tp_bshift
;
222 while ((avail
= MIN(tpblks
, ntrec
- trecno
)) > 0) {
223 slp
->req
[trecno
].dblk
= dblkno
;
224 slp
->req
[trecno
].count
= avail
;
226 spcl
.c_tapea
+= avail
;
229 dblkno
+= avail
<< (tp_bshift
- dev_bshift
);
241 msg("write error on %s\n", tape
);
242 quit("Cannot recover\n");
245 msg("write error %d blocks into volume %d\n", blocksthisvol
, tapeno
);
246 broadcast("DUMP WRITE ERROR!\n");
247 if (!query("Do you want to restart?"))
249 msg("Closing this volume. Prepare to restart with new media;\n");
250 msg("this dump volume will be rewritten.\n");
261 quit("Broken pipe\n");
266 * Update xferrate stats
279 ttaken
= tnow
- tstart_volume
;
280 blocks
= spcl
.c_tapea
- tapea_volume
;
281 msg("Volume %d completed at: %s", tapeno
,
288 msg("Volume %d took %d:%02d:%02d\n", tapeno
,
289 ttaken
/ 3600, (ttaken
% 3600) / 60, ttaken
% 60);
290 msg("Volume %d transfer rate: %ld KB/s\n", tapeno
,
292 xferrate
+= blocks
/ ttaken
;
300 * information message upon receipt of SIGINFO
301 * (derived from optr.c::timeest())
304 statussig(int notused
)
308 int save_errno
= errno
;
310 if (blockswritten
< 500)
315 (void) time((time_t *) &tnow
);
317 if (blockswritten
> tapesize
)
318 tapesize
= blockswritten
;
319 deltat
= tstart_writing
- tnow
+ (1.0 * (tnow
- tstart_writing
))
320 / blockswritten
* tapesize
;
321 (void)snprintf(msgbuf
, sizeof(msgbuf
),
322 "%3.2f%% done at %ld KB/s, finished in %d:%02d\n",
323 (blockswritten
* 100.0) / tapesize
,
324 (spcl
.c_tapea
- tapea_volume
) / (tnow
- tstart_volume
),
325 (int)(deltat
/ 3600), (int)((deltat
% 3600) / 60));
326 write(STDERR_FILENO
, msgbuf
, strlen(msgbuf
));
337 int siz
= (char *)nextblock
- (char *)slp
->req
;
339 slp
->req
[trecno
].count
= 0; /* Sentinel */
341 if (atomic_write( slp
->fd
, (char *)slp
->req
, siz
) != siz
)
342 quit("error writing command pipe: %s\n", strerror(errno
));
343 slp
->sent
= 1; /* we sent a request, read the response later */
345 lastfirstrec
= slp
->firstrec
;
347 if (++slp
>= &slaves
[SLAVES
])
350 /* Read results back from next slave */
352 if (atomic_read( slp
->fd
, (char *)&got
, sizeof got
)
354 perror(" DUMP: error reading command pipe in master");
359 /* Check for end of tape */
360 if (got
< writesize
) {
361 msg("End of tape detected\n");
364 * Drain the results, don't care what the values were.
365 * If we read them here then trewind won't...
367 for (i
= 0; i
< SLAVES
; i
++) {
368 if (slaves
[i
].sent
) {
369 if (atomic_read( slaves
[i
].fd
,
370 (char *)&got
, sizeof got
)
372 perror(" DUMP: error reading command pipe in master");
386 if (spcl
.c_type
!= TS_END
) {
387 for (i
= 0; i
< spcl
.c_count
; i
++)
388 if (spcl
.c_addr
[i
] != 0)
391 slp
->count
= lastspclrec
+ blks
+ 1 - spcl
.c_tapea
;
392 slp
->tapea
= spcl
.c_tapea
;
393 slp
->firstrec
= lastfirstrec
+ ntrec
;
395 nextblock
= slp
->tblock
;
398 blockswritten
+= ntrec
;
399 blocksthisvol
+= ntrec
;
400 if (!pipeout
&& !unlimited
&& (blocksperfile
?
401 (blocksthisvol
>= blocksperfile
) : (asize
> tsize
))) {
409 * Executes the command in a shell.
410 * Returns -1 if an error occured, the exit status of
411 * the command on success.
413 int system_command(const char *command
, const char *device
, int volnum
) {
415 char commandstr
[4096];
419 perror(" DUMP: unable to fork");
425 snprintf(commandstr
, sizeof(commandstr
), "%s %s %d", command
, device
, volnum
);
426 commandstr
[sizeof(commandstr
) - 1] = '\0';
427 execl("/bin/sh", "sh", "-c", commandstr
, NULL
);
428 perror(" DUMP: unable to execute shell");
432 if (waitpid(pid
, &status
, 0) == -1) {
433 if (errno
!= EINTR
) {
434 perror(" DUMP: waitpid error");
438 if (WIFEXITED(status
))
439 return WEXITSTATUS(status
);
452 for (f
= 0; f
< SLAVES
; f
++) {
454 * Drain the results, but unlike EOT we DO (or should) care
455 * what the return values were, since if we detect EOT after
456 * we think we've written the last blocks to the tape anyway,
457 * we have to replay those blocks with rollforward.
459 * fixme: punt for now.
461 if (slaves
[f
].sent
) {
462 if (atomic_read( slaves
[f
].fd
, (char *)&got
, sizeof got
)
464 perror(" DUMP: error reading command pipe in master");
468 if (got
!= writesize
) {
469 msg("EOT detected in last 2 tape records!\n");
470 msg("Use a longer tape, decrease the size estimate\n");
471 quit("or use no size estimate at all.\n");
474 (void) close(slaves
[f
].fd
);
476 while (wait((int *)NULL
) >= 0) /* wait for any signals from slaves */
481 msg("Closing %s\n", tape
);
486 while (rmtopen(tape
, 0) < 0)
493 (void) close(tapefd
);
494 while ((f
= open(tape
, 0)) < 0)
501 msg("Launching %s\n", eot_script
);
502 eot_code
= system_command(eot_script
, tape
, tapeno
);
504 if (eot_code
!= 0 && eot_code
!= 1) {
505 msg("Dump aborted by the end of tape script\n");
517 if (nexttape
|| Mflag
|| (eot_code
== 0) )
520 msg("Change Volumes: Mount volume #%d\n", tapeno
+1);
521 broadcast("CHANGE DUMP VOLUMES!\7\7\n");
523 while (!query("Is the new volume mounted and ready to go?"))
524 if (query("Do you want to abort?")) {
533 register struct req
*p
, *q
, *prev
;
534 register struct slave
*tslp
;
535 int i
, size
, savedtapea
, got
;
536 union u_spcl
*ntb
, *otb
;
541 tslp
= &slaves
[SLAVES
];
542 ntb
= (union u_spcl
*)tslp
->tblock
[1];
545 * Each of the N slaves should have requests that need to
546 * be replayed on the next tape. Use the extra slave buffers
547 * (slaves[SLAVES]) to construct request lists to be sent to
548 * each slave in turn.
550 for (i
= 0; i
< SLAVES
; i
++) {
552 otb
= (union u_spcl
*)slp
->tblock
;
555 * For each request in the current slave, copy it to tslp.
559 for (p
= slp
->req
; p
->count
> 0; p
+= p
->count
) {
562 *ntb
++ = *otb
++; /* copy the datablock also */
567 quit("rollforward: protocol botch");
579 nextblock
= tslp
->tblock
;
580 savedtapea
= spcl
.c_tapea
;
581 spcl
.c_tapea
= slp
->tapea
;
583 spcl
.c_tapea
= savedtapea
;
584 lastspclrec
= savedtapea
- 1;
586 size
= (char *)ntb
- (char *)q
;
587 if (atomic_write( slp
->fd
, (char *)q
, size
) != size
) {
588 perror(" DUMP: error writing command pipe");
593 lastfirstrec
= slp
->firstrec
;
595 if (++slp
>= &slaves
[SLAVES
])
600 if (prev
->dblk
!= 0) {
602 * If the last one was a disk block, make the
603 * first of this one be the last bit of that disk
606 q
->dblk
= prev
->dblk
+
607 prev
->count
* (TP_BSIZE
/ DEV_BSIZE
);
608 ntb
= (union u_spcl
*)tslp
->tblock
;
611 * It wasn't a disk block. Copy the data to its
612 * new location in the buffer.
615 *((union u_spcl
*)tslp
->tblock
) = *ntb
;
616 ntb
= (union u_spcl
*)tslp
->tblock
[1];
620 nextblock
= slp
->tblock
;
623 *(union u_spcl
*)(*(nextblock
)++) = *(union u_spcl
*)tslp
->tblock
;
630 * Clear the first slaves' response. One hopes that it
631 * worked ok, otherwise the tape is much too short!
634 if (atomic_read( slp
->fd
, (char *)&got
, sizeof got
)
636 perror(" DUMP: error reading command pipe in master");
641 if (got
!= writesize
) {
642 quit("EOT detected at start of the tape!\n");
648 if (spcl
.c_type
!= TS_END
) {
649 for (i
= 0; i
< spcl
.c_count
; i
++)
650 if (spcl
.c_addr
[i
] != 0)
654 slp
->firstrec
= lastfirstrec
+ ntrec
;
655 slp
->count
= lastspclrec
+ blks
+ 1 - spcl
.c_tapea
;
658 blockswritten
+= ntrec
;
659 blocksthisvol
+= ntrec
;
664 * We implement taking and restoring checkpoints on the tape level.
665 * When each tape is opened, a new process is created by forking; this
666 * saves all of the necessary context in the parent. The child
667 * continues the dump; the parent waits around, saving the context.
668 * If the child returns X_REWRITE, then it had problems writing that tape;
669 * this causes the parent to fork again, duplicating the context, and
670 * everything continues as if nothing had happened.
673 startnewtape(int top
)
681 void (*interrupt_save
) __P((int signo
));
682 #else /* __linux__ */
684 void (*interrupt_save
)();
686 sig_t interrupt_save
;
688 #endif /* __linux__ */
690 interrupt_save
= signal(SIGINT
, SIG_IGN
);
691 parentpid
= getpid();
692 tapea_volume
= spcl
.c_tapea
;
694 (void)time4(&tstart_volume
);
696 (void)time((&tstart_volume
);
700 (void)signal(SIGINT
, interrupt_save
);
702 * All signals are inherited...
706 msg("Context save fork fails in parent %d\n", parentpid
);
712 * save the context by waiting
713 * until the child doing all of the work returns.
714 * don't catch the interrupt
716 signal(SIGINT
, SIG_IGN
);
718 msg("Tape: %d; parent process: %d child process %d\n",
719 tapeno
+1, parentpid
, childpid
);
721 while ((waitpid
= wait(&status
)) != childpid
)
722 if (waitpid
!= rshpid
)
723 msg("Parent %d waiting for child %d has another child %d return\n",
724 parentpid
, childpid
, waitpid
);
726 msg("Child %d returns LOB status %o\n",
727 childpid
, status
&0xFF);
729 status
= (status
>> 8) & 0xFF;
733 msg("Child %d finishes X_FINOK\n", childpid
);
736 msg("Child %d finishes X_ABORT\n", childpid
);
739 msg("Child %d finishes X_REWRITE\n", childpid
);
742 msg("Child %d finishes unknown %d\n",
753 goto restore_check_point
;
755 msg("Bad return code from dump: %d\n", status
);
759 } else { /* we are the child; just continue */
761 sleep(4); /* allow time for parent's message to get out */
762 msg("Child on Tape %d has parent %d, my pid = %d\n",
763 tapeno
+1, parentpid
, getpid());
766 * If we have a name like "/dev/rmt0,/dev/rmt1",
767 * use the name before the comma first, and save
768 * the remaining names for subsequent volumes.
770 tapeno
++; /* current tape sequence */
772 snprintf(tape
, MAXPATHLEN
, "%s%03d", tapeprefix
, tapeno
);
773 tape
[MAXPATHLEN
- 1] = '\0';
774 msg("Dumping volume %d on %s\n", tapeno
, tape
);
776 else if (nexttape
|| strchr(tapeprefix
, ',')) {
777 if (nexttape
&& *nexttape
)
778 tapeprefix
= nexttape
;
779 if ((p
= strchr(tapeprefix
, ',')) != NULL
) {
784 strncpy(tape
, tapeprefix
, MAXPATHLEN
);
785 tape
[MAXPATHLEN
- 1] = '\0';
786 msg("Dumping volume %d on %s\n", tapeno
, tape
);
789 while ((tapefd
= (host
? rmtopen(tape
, 2) : pipeout
?
791 open(tape
, O_WRONLY
|O_CREAT
, 0666))) < 0)
793 while ((tapefd
= (pipeout
? fileno(stdout
) :
794 open(tape
, O_WRONLY
|O_CREAT
, 0666))) < 0)
797 msg("Cannot open output \"%s\".\n", tape
);
798 if (!query("Do you want to retry the open?"))
802 enslave(); /* Share open tape file descriptor with slaves */
807 newtape
++; /* new tape signal */
808 spcl
.c_count
= slp
->count
;
810 * measure firstrec in TP_BSIZE units since restore doesn't
811 * know the correct ntrec value...
813 spcl
.c_firstrec
= slp
->firstrec
;
815 spcl
.c_type
= TS_TAPE
;
816 spcl
.c_flags
|= DR_NEWHEADER
;
817 writeheader((ino_t
)slp
->inode
);
818 spcl
.c_flags
&=~ DR_NEWHEADER
;
819 msg("Volume %d started at: %s", tapeno
,
821 ctime4(&tstart_volume
));
823 ctime(&tstart_volume
));
826 msg("Volume %d begins with blocks from inode %d\n",
835 if (master
!= 0 && master
!= getpid())
836 /* Signals master to call dumpabort */
837 (void) kill(master
, SIGTERM
);
840 msg("The ENTIRE dump is aborted.\n");
853 msg("pid = %d exits with status %d\n", getpid(), status
);
859 * proceed - handler for SIGUSR2, used to synchronize IO between the slaves.
866 siglongjmp(jmpbuf
, 1);
874 #ifdef LINUX_FORK_BUG
882 signal(SIGTERM
, dumpabort
); /* Slave sends SIGTERM on dumpabort() */
883 signal(SIGPIPE
, sigpipe
);
884 signal(SIGUSR1
, tperror
); /* Slave sends SIGUSR1 on tape errors */
885 signal(SIGUSR2
, proceed
); /* Slave sends SIGUSR2 to next slave */
887 for (i
= 0; i
< SLAVES
; i
++) {
888 if (i
== slp
- &slaves
[0]) {
894 if (socketpair(AF_UNIX
, SOCK_STREAM
, 0, cmd
) < 0 ||
895 (slaves
[i
].pid
= fork()) < 0)
896 quit("too many slaves, %d (recompile smaller): %s\n",
899 slaves
[i
].fd
= cmd
[1];
901 if (slaves
[i
].pid
== 0) { /* Slave starts up here */
902 for (j
= 0; j
<= i
; j
++)
903 (void) close(slaves
[j
].fd
);
904 signal(SIGINT
, SIG_IGN
); /* Master handles this */
906 signal(SIGINFO
, SIG_IGN
);
909 #ifdef LINUX_FORK_BUG
910 if (atomic_write( cmd
[0], (char *) &i
, sizeof i
)
912 quit("master/slave protocol botched 3\n");
919 #ifdef LINUX_FORK_BUG
921 * Wait for all slaves to _actually_ start to circumvent a bug in
922 * Linux kernels >= 2.1.3 where a signal sent to a child that hasn't
923 * returned from fork() causes a SEGV in the child process
925 for (i
= 0; i
< SLAVES
; i
++)
926 if (atomic_read( slaves
[i
].fd
, (char *) &j
, sizeof j
) != sizeof j
)
927 quit("master/slave protocol botched 4\n");
930 for (i
= 0; i
< SLAVES
; i
++)
931 (void) atomic_write( slaves
[i
].fd
,
932 (char *) &slaves
[(i
+ 1) % SLAVES
].pid
,
933 sizeof slaves
[0].pid
);
943 for (i
= 0; i
< SLAVES
; i
++)
944 if (slaves
[i
].pid
> 0) {
945 (void) kill(slaves
[i
].pid
, SIGKILL
);
951 * Synchronization - each process has a lockfile, and shares file
952 * descriptors to the following process's lockfile. When our write
953 * completes, we release our lock on the following process's lock-
954 * file, allowing the following process to lock it and proceed. We
955 * get the lock back for the next cycle by swapping descriptors.
958 doslave(int cmd
, int slave_number
)
961 int nextslave
, size
, eot_count
;
962 volatile int wrote
= 0;
969 * Need our own seek pointer.
971 (void) close(diskfd
);
972 if ((diskfd
= open(disk
, O_RDONLY
)) < 0)
973 quit("slave couldn't reopen disk: %s\n", strerror(errno
));
976 retval
= dump_fs_open(disk
, &fs
);
978 quit("slave couldn't reopen disk: %s\n", error_message(retval
));
979 #endif /* __linux__ */
982 * Need the pid of the next slave in the loop...
984 if ((nread
= atomic_read( cmd
, (char *)&nextslave
, sizeof nextslave
))
985 != sizeof nextslave
) {
986 quit("master/slave protocol botched - didn't get pid of next slave.\n");
990 * Get list of blocks to dump, read the blocks into tape buffer
992 while ((nread
= atomic_read( cmd
, (char *)slp
->req
, reqsiz
)) == reqsiz
) {
993 register struct req
*p
= slp
->req
;
995 for (trecno
= 0; trecno
< ntrec
;
996 trecno
+= p
->count
, p
+= p
->count
) {
998 bread(p
->dblk
, slp
->tblock
[trecno
],
999 p
->count
* TP_BSIZE
);
1001 if (p
->count
!= 1 || atomic_read( cmd
,
1002 (char *)slp
->tblock
[trecno
],
1003 TP_BSIZE
) != TP_BSIZE
)
1004 quit("master/slave protocol botched.\n");
1007 if (setjmp(jmpbuf
) == 0) {
1015 /* Try to write the data... */
1020 while (eot_count
< 10 && size
< writesize
) {
1023 wrote
= rmtwrite(slp
->tblock
[0]+size
,
1027 wrote
= write(tapefd
, slp
->tblock
[0]+size
,
1030 printf("slave %d wrote %d\n", slave_number
, wrote
);
1040 if (size
!= writesize
)
1041 printf("slave %d only wrote %d out of %d bytes and gave up.\n",
1042 slave_number
, size
, writesize
);
1046 * Handle ENOSPC as an EOT condition.
1048 if (wrote
< 0 && errno
== ENOSPC
) {
1057 (void) kill(master
, SIGUSR1
);
1058 sigemptyset(&sigset
);
1060 sigsuspend(&sigset
);
1063 * pass size of write back to master
1064 * (for EOT handling)
1066 (void) atomic_write( cmd
, (char *)&size
, sizeof size
);
1070 * If partial write, don't want next slave to go.
1071 * Also jolts him awake.
1073 (void) kill(nextslave
, SIGUSR2
);
1076 quit("error reading command pipe: %s\n", strerror(errno
));
1080 * Since a read from a pipe may not return all we asked for,
1081 * or a write may not write all we ask if we get a signal,
1082 * loop until the count is satisfied (or error).
1085 atomic_read(int fd
, void *buf
, size_t count
)
1087 int got
, need
= count
;
1090 while ((got
= read(fd
, buf
, need
)) > 0 && (need
-= got
) > 0)
1092 } while (got
== -1 && errno
== EINTR
);
1093 return (got
< 0 ? got
: count
- need
);
1097 * Since a read from a pipe may not return all we asked for,
1098 * or a write may not write all we ask if we get a signal,
1099 * loop until the count is satisfied (or error).
1102 atomic_write(int fd
, const void *buf
, size_t count
)
1104 int got
, need
= count
;
1107 while ((got
= write(fd
, buf
, need
)) > 0 && (need
-= got
) > 0)
1109 } while (got
== -1 && errno
== EINTR
);
1110 return (got
< 0 ? got
: count
- need
);