]>
git.wh0rd.org - dump.git/blob - dump/tape.c
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@noos.fr>, 1999-2000
6 * Stelian Pop <pop@noos.fr> - AlcĂ´ve <www.alcove.fr>, 2000
10 * Copyright (c) 1980, 1991, 1993
11 * The Regents of the University of California. All rights reserved.
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
16 * 1. Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 * 3. All advertising materials mentioning features or use of this software
22 * must display the following acknowledgement:
23 * This product includes software developed by the University of
24 * California, Berkeley and its contributors.
25 * 4. Neither the name of the University nor the names of its contributors
26 * may be used to endorse or promote products derived from this software
27 * without specific prior written permission.
29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
32 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
43 static const char rcsid
[] =
44 "$Id: tape.c,v 1.25 2000/12/04 15:43:16 stelian Exp $";
48 #include <sys/types.h>
49 #include <linux/types.h>
51 #include <sys/param.h>
52 #include <sys/socket.h>
56 #include <linux/ext2_fs.h>
57 #include <bsdcompat.h>
60 #include <sys/vnode.h>
63 #include <ufs/inode.h>
65 #include <ufs/ufs/dinode.h>
66 #include <ufs/ffs/fs.h>
68 #endif /* __linux__ */
70 #include <protocols/dumprestore.h>
77 #include <compaterr.h>
87 #include <ext2fs/ext2fs.h>
92 int writesize
; /* size of malloc()ed buffer for tape */
93 long lastspclrec
= -1; /* tape block number of last written header */
94 int trecno
= 0; /* next record to write in current block */
95 extern long blocksperfile
; /* number of blocks per output file */
96 long blocksthisvol
; /* number of blocks on current output file */
97 extern int ntrec
; /* blocking factor on tape */
104 static ssize_t atomic_read
__P((int, void *, size_t));
105 static ssize_t atomic_write
__P((int, const void *, size_t));
106 static void doslave
__P((int, int));
107 static void enslave
__P((void));
108 static void flushtape
__P((void));
109 static void killall
__P((void));
110 static void rollforward
__P((void));
111 static int system_command
__P((const char *, const char *, int));
114 * Concurrent dump mods (Caltech) - disk block reading and tape writing
115 * are exported to several slave processes. While one slave writes the
116 * tape, the others read disk blocks; they pass control of the tape in
117 * a ring via signals. The parent process traverses the filesystem and
118 * sends writeheader()'s and lists of daddr's to the slaves via pipes.
119 * The following structure defines the instruction packets sent to slaves.
127 #define SLAVES 3 /* 1 slave writing, 1 reading, 1 for slack */
129 int tapea
; /* header number at start of this chunk */
130 int count
; /* count to next header (used for TS_TAPE */
132 int inode
; /* inode that we are currently dealing with */
133 int fd
; /* FD for this slave */
134 int pid
; /* PID for this slave */
135 int sent
; /* 1 == we've sent this slave requests */
136 int firstrec
; /* record number of this block */
137 char (*tblock
)[TP_BSIZE
]; /* buffer for data blocks */
138 struct req
*req
; /* buffer for requests */
142 char (*nextblock
)[TP_BSIZE
];
144 static time_t tstart_volume
; /* time of volume start */
145 static int tapea_volume
; /* value of spcl.c_tapea at volume start */
147 int master
; /* pid of master, for sending error signals */
148 int tenths
; /* length of tape used per block written */
149 static int caught
; /* have we caught the signal to proceed? */
150 static int ready
; /* have we reached the lock point without having */
151 /* received the SIGUSR2 signal from the prev slave? */
152 static sigjmp_buf jmpbuf
; /* where to jump to if we are ready when the */
153 /* SIGUSR2 arrives from the previous slave */
158 int pgoff
= getpagesize() - 1;
162 writesize
= ntrec
* TP_BSIZE
;
163 reqsiz
= (ntrec
+ 1) * sizeof(struct req
);
165 * CDC 92181's and 92185's make 0.8" gaps in 1600-bpi start/stop mode
166 * (see DEC TU80 User's Guide). The shorter gaps of 6250-bpi require
167 * repositioning after stopping, i.e, streaming mode, where the gap is
168 * variable, 0.30" to 0.45". The gap is maximal when the tape stops.
170 if (blocksperfile
== 0 && !unlimited
)
171 tenths
= writesize
/ density
+
172 (cartridge
? 16 : density
== 625 ? 5 : 8);
174 * Allocate tape buffer contiguous with the array of instruction
175 * packets, so flushtape() can write them together with one write().
176 * Align tape buffer on page boundary to speed up tape write().
178 for (i
= 0; i
<= SLAVES
; i
++) {
180 malloc((unsigned)(reqsiz
+ writesize
+ pgoff
+ TP_BSIZE
));
183 slaves
[i
].tblock
= (char (*)[TP_BSIZE
])
185 (((long)&buf
[reqsiz
] + pgoff
) &~ pgoff
);
187 (((long)&buf
[ntrec
+ 1] + pgoff
) &~ pgoff
);
189 slaves
[i
].req
= (struct req
*)slaves
[i
].tblock
- ntrec
- 1;
195 nextblock
= slp
->tblock
;
200 writerec(const void *dp
, int isspcl
)
203 slp
->req
[trecno
].dblk
= (daddr_t
)0;
204 slp
->req
[trecno
].count
= 1;
205 /* XXX post increment triggers an egcs-1.1.2-12 bug on alpha/sparc */
206 *(union u_spcl
*)(*(nextblock
)) = *(union u_spcl
*)dp
;
209 lastspclrec
= spcl
.c_tapea
;
217 dumpblock(daddr_t blkno
, int size
)
219 int avail
, tpblks
, dblkno
;
221 dblkno
= fsbtodb(sblock
, blkno
);
222 tpblks
= size
>> tp_bshift
;
223 while ((avail
= MIN(tpblks
, ntrec
- trecno
)) > 0) {
224 slp
->req
[trecno
].dblk
= dblkno
;
225 slp
->req
[trecno
].count
= avail
;
227 spcl
.c_tapea
+= avail
;
230 dblkno
+= avail
<< (tp_bshift
- dev_bshift
);
242 msg("write error on %s\n", tape
);
243 quit("Cannot recover\n");
246 msg("write error %d blocks into volume %d\n", blocksthisvol
, tapeno
);
247 broadcast("DUMP WRITE ERROR!\n");
248 if (!query("Do you want to restart?"))
250 msg("Closing this volume. Prepare to restart with new media;\n");
251 msg("this dump volume will be rewritten.\n");
262 quit("Broken pipe\n");
267 * Update xferrate stats
280 ttaken
= tnow
- tstart_volume
;
281 blocks
= spcl
.c_tapea
- tapea_volume
;
282 msg("Volume %d completed at: %s", tapeno
,
289 msg("Volume %d took %d:%02d:%02d\n", tapeno
,
290 ttaken
/ 3600, (ttaken
% 3600) / 60, ttaken
% 60);
291 msg("Volume %d transfer rate: %ld KB/s\n", tapeno
,
293 xferrate
+= blocks
/ ttaken
;
301 * information message upon receipt of SIGINFO
302 * (derived from optr.c::timeest())
305 statussig(int notused
)
309 int save_errno
= errno
;
311 if (blockswritten
< 500)
316 (void) time((time_t *) &tnow
);
318 if (blockswritten
> tapesize
)
319 tapesize
= blockswritten
;
320 deltat
= tstart_writing
- tnow
+ (1.0 * (tnow
- tstart_writing
))
321 / blockswritten
* tapesize
;
322 (void)snprintf(msgbuf
, sizeof(msgbuf
),
323 "%3.2f%% done at %ld KB/s, finished in %d:%02d\n",
324 (blockswritten
* 100.0) / tapesize
,
325 (spcl
.c_tapea
- tapea_volume
) / (tnow
- tstart_volume
),
326 (int)(deltat
/ 3600), (int)((deltat
% 3600) / 60));
327 write(STDERR_FILENO
, msgbuf
, strlen(msgbuf
));
338 int siz
= (char *)nextblock
- (char *)slp
->req
;
340 slp
->req
[trecno
].count
= 0; /* Sentinel */
342 if (atomic_write( slp
->fd
, (char *)slp
->req
, siz
) != siz
)
343 quit("error writing command pipe: %s\n", strerror(errno
));
344 slp
->sent
= 1; /* we sent a request, read the response later */
346 lastfirstrec
= slp
->firstrec
;
348 if (++slp
>= &slaves
[SLAVES
])
351 /* Read results back from next slave */
353 if (atomic_read( slp
->fd
, (char *)&got
, sizeof got
)
355 perror(" DUMP: error reading command pipe in master");
360 /* Check for end of tape */
361 if (got
< writesize
) {
362 msg("End of tape detected\n");
365 * Drain the results, don't care what the values were.
366 * If we read them here then trewind won't...
368 for (i
= 0; i
< SLAVES
; i
++) {
369 if (slaves
[i
].sent
) {
370 if (atomic_read( slaves
[i
].fd
,
371 (char *)&got
, sizeof got
)
373 perror(" DUMP: error reading command pipe in master");
387 if (spcl
.c_type
!= TS_END
) {
388 for (i
= 0; i
< spcl
.c_count
; i
++)
389 if (spcl
.c_addr
[i
] != 0)
392 slp
->count
= lastspclrec
+ blks
+ 1 - spcl
.c_tapea
;
393 slp
->tapea
= spcl
.c_tapea
;
394 slp
->firstrec
= lastfirstrec
+ ntrec
;
396 nextblock
= slp
->tblock
;
399 blockswritten
+= ntrec
;
400 blocksthisvol
+= ntrec
;
401 if (!pipeout
&& !unlimited
&& (blocksperfile
?
402 (blocksthisvol
>= blocksperfile
) : (asize
> tsize
))) {
410 * Executes the command in a shell.
411 * Returns -1 if an error occured, the exit status of
412 * the command on success.
414 int system_command(const char *command
, const char *device
, int volnum
) {
416 char commandstr
[4096];
420 perror(" DUMP: unable to fork");
426 #if OLD_STYLE_FSCRIPT
427 snprintf(commandstr
, sizeof(commandstr
), "%s", command
);
429 snprintf(commandstr
, sizeof(commandstr
), "%s %s %d", command
, device
, volnum
);
431 commandstr
[sizeof(commandstr
) - 1] = '\0';
432 execl("/bin/sh", "sh", "-c", commandstr
, NULL
);
433 perror(" DUMP: unable to execute shell");
437 if (waitpid(pid
, &status
, 0) == -1) {
438 if (errno
!= EINTR
) {
439 perror(" DUMP: waitpid error");
443 if (WIFEXITED(status
))
444 return WEXITSTATUS(status
);
457 for (f
= 0; f
< SLAVES
; f
++) {
459 * Drain the results, but unlike EOT we DO (or should) care
460 * what the return values were, since if we detect EOT after
461 * we think we've written the last blocks to the tape anyway,
462 * we have to replay those blocks with rollforward.
464 * fixme: punt for now.
466 if (slaves
[f
].sent
) {
467 if (atomic_read( slaves
[f
].fd
, (char *)&got
, sizeof got
)
469 perror(" DUMP: error reading command pipe in master");
473 if (got
!= writesize
) {
474 msg("EOT detected in last 2 tape records!\n");
475 msg("Use a longer tape, decrease the size estimate\n");
476 quit("or use no size estimate at all.\n");
479 (void) close(slaves
[f
].fd
);
481 while (wait((int *)NULL
) >= 0) /* wait for any signals from slaves */
486 msg("Closing %s\n", tape
);
491 while (rmtopen(tape
, 0) < 0)
498 (void) close(tapefd
);
499 while ((f
= open(tape
, 0)) < 0)
504 if (eot_script
&& spcl
.c_type
!= TS_END
) {
505 msg("Launching %s\n", eot_script
);
506 eot_code
= system_command(eot_script
, tape
, tapeno
);
508 if (eot_code
!= 0 && eot_code
!= 1) {
509 msg("Dump aborted by the end of tape script\n");
521 if (nexttape
|| Mflag
|| (eot_code
== 0) )
524 msg("Change Volumes: Mount volume #%d\n", tapeno
+1);
525 broadcast("CHANGE DUMP VOLUMES!\7\7\n");
527 while (!query("Is the new volume mounted and ready to go?"))
528 if (query("Do you want to abort?")) {
537 register struct req
*p
, *q
, *prev
;
538 register struct slave
*tslp
;
539 int i
, size
, savedtapea
, got
;
540 union u_spcl
*ntb
, *otb
;
545 tslp
= &slaves
[SLAVES
];
546 ntb
= (union u_spcl
*)tslp
->tblock
[1];
549 * Each of the N slaves should have requests that need to
550 * be replayed on the next tape. Use the extra slave buffers
551 * (slaves[SLAVES]) to construct request lists to be sent to
552 * each slave in turn.
554 for (i
= 0; i
< SLAVES
; i
++) {
556 otb
= (union u_spcl
*)slp
->tblock
;
559 * For each request in the current slave, copy it to tslp.
563 for (p
= slp
->req
; p
->count
> 0; p
+= p
->count
) {
566 *ntb
++ = *otb
++; /* copy the datablock also */
571 quit("rollforward: protocol botch");
583 nextblock
= tslp
->tblock
;
584 savedtapea
= spcl
.c_tapea
;
585 spcl
.c_tapea
= slp
->tapea
;
587 spcl
.c_tapea
= savedtapea
;
588 lastspclrec
= savedtapea
- 1;
590 size
= (char *)ntb
- (char *)q
;
591 if (atomic_write( slp
->fd
, (char *)q
, size
) != size
) {
592 perror(" DUMP: error writing command pipe");
597 lastfirstrec
= slp
->firstrec
;
599 if (++slp
>= &slaves
[SLAVES
])
604 if (prev
->dblk
!= 0) {
606 * If the last one was a disk block, make the
607 * first of this one be the last bit of that disk
610 q
->dblk
= prev
->dblk
+
611 prev
->count
* (TP_BSIZE
/ DEV_BSIZE
);
612 ntb
= (union u_spcl
*)tslp
->tblock
;
615 * It wasn't a disk block. Copy the data to its
616 * new location in the buffer.
619 *((union u_spcl
*)tslp
->tblock
) = *ntb
;
620 ntb
= (union u_spcl
*)tslp
->tblock
[1];
624 nextblock
= slp
->tblock
;
627 /* XXX post increment triggers an egcs-1.1.2-12 bug on alpha/sparc */
628 *(union u_spcl
*)(*nextblock
) = *(union u_spcl
*)tslp
->tblock
;
635 * Clear the first slaves' response. One hopes that it
636 * worked ok, otherwise the tape is much too short!
639 if (atomic_read( slp
->fd
, (char *)&got
, sizeof got
)
641 perror(" DUMP: error reading command pipe in master");
646 if (got
!= writesize
) {
647 quit("EOT detected at start of the tape!\n");
653 if (spcl
.c_type
!= TS_END
) {
654 for (i
= 0; i
< spcl
.c_count
; i
++)
655 if (spcl
.c_addr
[i
] != 0)
659 slp
->firstrec
= lastfirstrec
+ ntrec
;
660 slp
->count
= lastspclrec
+ blks
+ 1 - spcl
.c_tapea
;
663 blockswritten
+= ntrec
;
664 blocksthisvol
+= ntrec
;
669 * We implement taking and restoring checkpoints on the tape level.
670 * When each tape is opened, a new process is created by forking; this
671 * saves all of the necessary context in the parent. The child
672 * continues the dump; the parent waits around, saving the context.
673 * If the child returns X_REWRITE, then it had problems writing that tape;
674 * this causes the parent to fork again, duplicating the context, and
675 * everything continues as if nothing had happened.
678 startnewtape(int top
)
689 sigaddset(&sigs
, SIGINT
);
690 sigprocmask(SIG_BLOCK
, &sigs
, NULL
);
691 #else /* __linux__ */
693 void (*interrupt_save
)();
695 sig_t interrupt_save
;
697 interrupt_save
= signal(SIGINT
, SIG_IGN
);
698 #endif /* __linux__ */
700 parentpid
= getpid();
701 tapea_volume
= spcl
.c_tapea
;
703 (void)time4(&tstart_volume
);
705 (void)time((&tstart_volume
);
710 sigprocmask(SIG_UNBLOCK
, &sigs
, NULL
);
712 (void)signal(SIGINT
, interrupt_save
);
715 * All signals are inherited...
719 msg("Context save fork fails in parent %d\n", parentpid
);
725 * save the context by waiting
726 * until the child doing all of the work returns.
727 * don't catch the interrupt
730 sigprocmask(SIG_BLOCK
, &sigs
, NULL
);
732 signal(SIGINT
, SIG_IGN
);
735 msg("Tape: %d; parent process: %d child process %d\n",
736 tapeno
+1, parentpid
, childpid
);
738 while ((waitpid
= wait(&status
)) != childpid
)
739 if (waitpid
!= rshpid
)
740 msg("Parent %d waiting for child %d has another child %d return\n",
741 parentpid
, childpid
, waitpid
);
743 msg("Child %d returns LOB status %o\n",
744 childpid
, status
&0xFF);
746 status
= (status
>> 8) & 0xFF;
750 msg("Child %d finishes X_FINOK\n", childpid
);
753 msg("Child %d finishes X_ABORT\n", childpid
);
756 msg("Child %d finishes X_REWRITE\n", childpid
);
759 msg("Child %d finishes unknown %d\n",
770 goto restore_check_point
;
772 msg("Bad return code from dump: %d\n", status
);
776 } else { /* we are the child; just continue */
778 sleep(4); /* allow time for parent's message to get out */
779 msg("Child on Tape %d has parent %d, my pid = %d\n",
780 tapeno
+1, parentpid
, getpid());
783 * If we have a name like "/dev/rmt0,/dev/rmt1",
784 * use the name before the comma first, and save
785 * the remaining names for subsequent volumes.
787 tapeno
++; /* current tape sequence */
789 snprintf(tape
, MAXPATHLEN
, "%s%03d", tapeprefix
, tapeno
);
790 tape
[MAXPATHLEN
- 1] = '\0';
791 msg("Dumping volume %d on %s\n", tapeno
, tape
);
793 else if (nexttape
|| strchr(tapeprefix
, ',')) {
794 if (nexttape
&& *nexttape
)
795 tapeprefix
= nexttape
;
796 if ((p
= strchr(tapeprefix
, ',')) != NULL
) {
801 strncpy(tape
, tapeprefix
, MAXPATHLEN
);
802 tape
[MAXPATHLEN
- 1] = '\0';
803 msg("Dumping volume %d on %s\n", tapeno
, tape
);
806 while ((tapefd
= (host
? rmtopen(tape
, 2) : pipeout
?
808 open(tape
, O_WRONLY
|O_CREAT
, 0666))) < 0)
810 while ((tapefd
= (pipeout
? fileno(stdout
) :
811 open(tape
, O_WRONLY
|O_CREAT
, 0666))) < 0)
814 msg("Cannot open output \"%s\".\n", tape
);
815 if (!query("Do you want to retry the open?"))
819 enslave(); /* Share open tape file descriptor with slaves */
824 newtape
++; /* new tape signal */
825 spcl
.c_count
= slp
->count
;
827 * measure firstrec in TP_BSIZE units since restore doesn't
828 * know the correct ntrec value...
830 spcl
.c_firstrec
= slp
->firstrec
;
832 spcl
.c_type
= TS_TAPE
;
833 spcl
.c_flags
|= DR_NEWHEADER
;
834 writeheader((ino_t
)slp
->inode
);
835 spcl
.c_flags
&=~ DR_NEWHEADER
;
836 msg("Volume %d started at: %s", tapeno
,
838 ctime4(&tstart_volume
));
840 ctime(&tstart_volume
));
843 msg("Volume %d begins with blocks from inode %d\n",
852 if (master
!= 0 && master
!= getpid())
853 /* Signals master to call dumpabort */
854 (void) kill(master
, SIGTERM
);
857 msg("The ENTIRE dump is aborted.\n");
870 msg("pid = %d exits with status %d\n", getpid(), status
);
876 * proceed - handler for SIGUSR2, used to synchronize IO between the slaves.
882 siglongjmp(jmpbuf
, 1);
890 #ifdef LINUX_FORK_BUG
898 { struct sigaction sa
;
899 memset(&sa
, 0, sizeof sa
);
900 sigemptyset(&sa
.sa_mask
);
901 sa
.sa_handler
= dumpabort
;
902 sigaction(SIGTERM
, &sa
, NULL
); /* Slave sends SIGTERM on dumpabort() */
903 sa
.sa_handler
= sigpipe
;
904 sigaction(SIGPIPE
, &sa
, NULL
);
905 sa
.sa_handler
= tperror
;
906 sigaction(SIGUSR1
, &sa
, NULL
); /* Slave sends SIGUSR1 on tape errors */
907 sa
.sa_handler
= proceed
;
908 sa
.sa_flags
= SA_RESTART
;
909 sigaction(SIGUSR2
, &sa
, NULL
); /* Slave sends SIGUSR2 to next slave */
912 for (i
= 0; i
< SLAVES
; i
++) {
913 if (i
== slp
- &slaves
[0]) {
919 if (socketpair(AF_UNIX
, SOCK_STREAM
, 0, cmd
) < 0 ||
920 (slaves
[i
].pid
= fork()) < 0)
921 quit("too many slaves, %d (recompile smaller): %s\n",
924 slaves
[i
].fd
= cmd
[1];
926 if (slaves
[i
].pid
== 0) { /* Slave starts up here */
928 for (j
= 0; j
<= i
; j
++)
929 (void) close(slaves
[j
].fd
);
931 sigaddset(&sigs
, SIGINT
); /* Master handles this */
933 sigaddset(&sigs
, SIGINFO
);
935 sigprocmask(SIG_BLOCK
, &sigs
, NULL
);
937 #ifdef LINUX_FORK_BUG
938 if (atomic_write( cmd
[0], (char *) &i
, sizeof i
)
940 quit("master/slave protocol botched 3\n");
947 #ifdef LINUX_FORK_BUG
949 * Wait for all slaves to _actually_ start to circumvent a bug in
950 * Linux kernels >= 2.1.3 where a signal sent to a child that hasn't
951 * returned from fork() causes a SEGV in the child process
953 for (i
= 0; i
< SLAVES
; i
++)
954 if (atomic_read( slaves
[i
].fd
, (char *) &j
, sizeof j
) != sizeof j
)
955 quit("master/slave protocol botched 4\n");
958 for (i
= 0; i
< SLAVES
; i
++)
959 (void) atomic_write( slaves
[i
].fd
,
960 (char *) &slaves
[(i
+ 1) % SLAVES
].pid
,
961 sizeof slaves
[0].pid
);
971 for (i
= 0; i
< SLAVES
; i
++)
972 if (slaves
[i
].pid
> 0) {
973 (void) kill(slaves
[i
].pid
, SIGKILL
);
979 * Synchronization - each process has a lockfile, and shares file
980 * descriptors to the following process's lockfile. When our write
981 * completes, we release our lock on the following process's lock-
982 * file, allowing the following process to lock it and proceed. We
983 * get the lock back for the next cycle by swapping descriptors.
986 doslave(int cmd
, int slave_number
)
989 int nextslave
, size
, eot_count
;
990 volatile int wrote
= 0;
997 * Need our own seek pointer.
999 (void) close(diskfd
);
1000 if ((diskfd
= open(disk
, O_RDONLY
)) < 0)
1001 quit("slave couldn't reopen disk: %s\n", strerror(errno
));
1004 retval
= dump_fs_open(disk
, &fs
);
1006 quit("slave couldn't reopen disk: %s\n", error_message(retval
));
1007 #endif /* __linux__ */
1010 * Need the pid of the next slave in the loop...
1012 if ((nread
= atomic_read( cmd
, (char *)&nextslave
, sizeof nextslave
))
1013 != sizeof nextslave
) {
1014 quit("master/slave protocol botched - didn't get pid of next slave.\n");
1018 * Get list of blocks to dump, read the blocks into tape buffer
1020 while ((nread
= atomic_read( cmd
, (char *)slp
->req
, reqsiz
)) == reqsiz
) {
1021 register struct req
*p
= slp
->req
;
1023 for (trecno
= 0; trecno
< ntrec
;
1024 trecno
+= p
->count
, p
+= p
->count
) {
1026 bread(p
->dblk
, slp
->tblock
[trecno
],
1027 p
->count
* TP_BSIZE
);
1029 if (p
->count
!= 1 || atomic_read( cmd
,
1030 (char *)slp
->tblock
[trecno
],
1031 TP_BSIZE
) != TP_BSIZE
)
1032 quit("master/slave protocol botched.\n");
1035 if (sigsetjmp(jmpbuf
, 1) == 0) {
1043 /* Try to write the data... */
1048 while (eot_count
< 10 && size
< writesize
) {
1051 wrote
= rmtwrite(slp
->tblock
[0]+size
,
1055 wrote
= write(tapefd
, slp
->tblock
[0]+size
,
1058 printf("slave %d wrote %d\n", slave_number
, wrote
);
1068 if (size
!= writesize
)
1069 printf("slave %d only wrote %d out of %d bytes and gave up.\n",
1070 slave_number
, size
, writesize
);
1074 * Handle ENOSPC as an EOT condition.
1076 if (wrote
< 0 && errno
== ENOSPC
) {
1085 (void) kill(master
, SIGUSR1
);
1086 sigemptyset(&sigset
);
1087 sigaddset(&sigset
, SIGINT
);
1089 sigsuspend(&sigset
);
1092 * pass size of write back to master
1093 * (for EOT handling)
1095 (void) atomic_write( cmd
, (char *)&size
, sizeof size
);
1099 * If partial write, don't want next slave to go.
1100 * Also jolts him awake.
1102 (void) kill(nextslave
, SIGUSR2
);
1105 quit("error reading command pipe: %s\n", strerror(errno
));
1109 * Since a read from a pipe may not return all we asked for,
1110 * or a write may not write all we ask if we get a signal,
1111 * loop until the count is satisfied (or error).
1114 atomic_read(int fd
, void *buf
, size_t count
)
1116 int got
, need
= count
;
1119 while ((got
= read(fd
, buf
, need
)) > 0 && (need
-= got
) > 0)
1121 } while (got
== -1 && errno
== EINTR
);
1122 return (got
< 0 ? got
: count
- need
);
1126 * Since a read from a pipe may not return all we asked for,
1127 * or a write may not write all we ask if we get a signal,
1128 * loop until the count is satisfied (or error).
1131 atomic_write(int fd
, const void *buf
, size_t count
)
1133 int got
, need
= count
;
1136 while ((got
= write(fd
, buf
, need
)) > 0 && (need
-= got
) > 0)
1138 } while (got
== -1 && errno
== EINTR
);
1139 return (got
< 0 ? got
: count
- need
);