freebsd-dev/bin/pax/ar_io.c
Warner Losh fbbd9655e5 Renumber copyright clause 4
Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.

Submitted by:	Jan Schaumann <jschauma@stevens.edu>
Pull Request:	https://github.com/freebsd/freebsd/pull/96
2017-02-28 23:42:47 +00:00

1289 lines
32 KiB
C

/*-
* Copyright (c) 1992 Keith Muller.
* Copyright (c) 1992, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Keith Muller of the University of California, San Diego.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
#if 0
static char sccsid[] = "@(#)ar_io.c 8.2 (Berkeley) 4/18/94";
#endif
#endif /* not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/mtio.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include "pax.h"
#include "options.h"
#include "extern.h"
/*
* Routines which deal directly with the archive I/O device/file.
*/
#define DMOD 0666 /* default mode of created archives */
#define EXT_MODE O_RDONLY /* open mode for list/extract */
#define AR_MODE (O_WRONLY | O_CREAT | O_TRUNC) /* mode for archive */
#define APP_MODE O_RDWR /* mode for append */
static char none[] = "<NONE>"; /* pseudo name for no file */
static char stdo[] = "<STDOUT>"; /* pseudo name for stdout */
static char stdn[] = "<STDIN>"; /* pseudo name for stdin */
static int arfd = -1; /* archive file descriptor */
static int artyp = ISREG; /* archive type: file/FIFO/tape */
static int arvol = 1; /* archive volume number */
static int lstrval = -1; /* return value from last i/o */
static int io_ok; /* i/o worked on volume after resync */
static int did_io; /* did i/o ever occur on volume? */
static int done; /* set via tty termination */
static struct stat arsb; /* stat of archive device at open */
static int invld_rec; /* tape has out of spec record size */
static int wr_trail = 1; /* trailer was rewritten in append */
static int can_unlnk = 0; /* do we unlink null archives? */
const char *arcname; /* printable name of archive */
const char *gzip_program; /* name of gzip program */
static pid_t zpid = -1; /* pid of child process */
static int get_phys(void);
static void ar_start_gzip(int, const char *, int);
/*
* ar_open()
* Opens the next archive volume. Determines the type of the device and
* sets up block sizes as required by the archive device and the format.
* Note: we may be called with name == NULL on the first open only.
* Return:
* -1 on failure, 0 otherwise
*/
int
ar_open(const char *name)
{
struct mtget mb;
if (arfd != -1)
(void)close(arfd);
arfd = -1;
can_unlnk = did_io = io_ok = invld_rec = 0;
artyp = ISREG;
flcnt = 0;
/*
* open based on overall operation mode
*/
switch (act) {
case LIST:
case EXTRACT:
if (name == NULL) {
arfd = STDIN_FILENO;
arcname = stdn;
} else if ((arfd = open(name, EXT_MODE, DMOD)) < 0)
syswarn(0, errno, "Failed open to read on %s", name);
if (arfd != -1 && gzip_program != NULL)
ar_start_gzip(arfd, gzip_program, 0);
break;
case ARCHIVE:
if (name == NULL) {
arfd = STDOUT_FILENO;
arcname = stdo;
} else if ((arfd = open(name, AR_MODE, DMOD)) < 0)
syswarn(0, errno, "Failed open to write on %s", name);
else
can_unlnk = 1;
if (arfd != -1 && gzip_program != NULL)
ar_start_gzip(arfd, gzip_program, 1);
break;
case APPND:
if (name == NULL) {
arfd = STDOUT_FILENO;
arcname = stdo;
} else if ((arfd = open(name, APP_MODE, DMOD)) < 0)
syswarn(0, errno, "Failed open to read/write on %s",
name);
break;
case COPY:
/*
* arfd not used in COPY mode
*/
arcname = none;
lstrval = 1;
return(0);
}
if (arfd < 0)
return(-1);
if (chdname != NULL)
if (chdir(chdname) != 0) {
syswarn(1, errno, "Failed chdir to %s", chdname);
return(-1);
}
/*
* set up is based on device type
*/
if (fstat(arfd, &arsb) < 0) {
syswarn(0, errno, "Failed stat on %s", arcname);
(void)close(arfd);
arfd = -1;
can_unlnk = 0;
return(-1);
}
if (S_ISDIR(arsb.st_mode)) {
paxwarn(0, "Cannot write an archive on top of a directory %s",
arcname);
(void)close(arfd);
arfd = -1;
can_unlnk = 0;
return(-1);
}
if (S_ISCHR(arsb.st_mode))
artyp = ioctl(arfd, MTIOCGET, &mb) ? ISCHR : ISTAPE;
else if (S_ISBLK(arsb.st_mode))
artyp = ISBLK;
else if ((lseek(arfd, (off_t)0L, SEEK_CUR) == -1) && (errno == ESPIPE))
artyp = ISPIPE;
else
artyp = ISREG;
/*
* make sure we beyond any doubt that we only can unlink regular files
* we created
*/
if (artyp != ISREG)
can_unlnk = 0;
/*
* if we are writing, we are done
*/
if (act == ARCHIVE) {
blksz = rdblksz = wrblksz;
lstrval = 1;
return(0);
}
/*
* set default blksz on read. APPNDs writes rdblksz on the last volume
* On all new archive volumes, we shift to wrblksz (if the user
* specified one, otherwise we will continue to use rdblksz). We
* must to set blocksize based on what kind of device the archive is
* stored.
*/
switch(artyp) {
case ISTAPE:
/*
* Tape drives come in at least two flavors. Those that support
* variable sized records and those that have fixed sized
* records. They must be treated differently. For tape drives
* that support variable sized records, we must make large
* reads to make sure we get the entire record, otherwise we
* will just get the first part of the record (up to size we
* asked). Tapes with fixed sized records may or may not return
* multiple records in a single read. We really do not care
* what the physical record size is UNLESS we are going to
* append. (We will need the physical block size to rewrite
* the trailer). Only when we are appending do we go to the
* effort to figure out the true PHYSICAL record size.
*/
blksz = rdblksz = MAXBLK;
break;
case ISPIPE:
case ISBLK:
case ISCHR:
/*
* Blocksize is not a major issue with these devices (but must
* be kept a multiple of 512). If the user specified a write
* block size, we use that to read. Under append, we must
* always keep blksz == rdblksz. Otherwise we go ahead and use
* the device optimal blocksize as (and if) returned by stat
* and if it is within pax specs.
*/
if ((act == APPND) && wrblksz) {
blksz = rdblksz = wrblksz;
break;
}
if ((arsb.st_blksize > 0) && (arsb.st_blksize < MAXBLK) &&
((arsb.st_blksize % BLKMULT) == 0))
rdblksz = arsb.st_blksize;
else
rdblksz = DEVBLK;
/*
* For performance go for large reads when we can without harm
*/
if ((act == APPND) || (artyp == ISCHR))
blksz = rdblksz;
else
blksz = MAXBLK;
break;
case ISREG:
/*
* if the user specified wrblksz works, use it. Under appends
* we must always keep blksz == rdblksz
*/
if ((act == APPND) && wrblksz && ((arsb.st_size%wrblksz)==0)){
blksz = rdblksz = wrblksz;
break;
}
/*
* See if we can find the blocking factor from the file size
*/
for (rdblksz = MAXBLK; rdblksz > 0; rdblksz -= BLKMULT)
if ((arsb.st_size % rdblksz) == 0)
break;
/*
* When we cannot find a match, we may have a flawed archive.
*/
if (rdblksz <= 0)
rdblksz = FILEBLK;
/*
* for performance go for large reads when we can
*/
if (act == APPND)
blksz = rdblksz;
else
blksz = MAXBLK;
break;
default:
/*
* should never happen, worse case, slow...
*/
blksz = rdblksz = BLKMULT;
break;
}
lstrval = 1;
return(0);
}
/*
* ar_close()
* closes archive device, increments volume number, and prints i/o summary
*/
void
ar_close(void)
{
int status;
if (arfd < 0) {
did_io = io_ok = flcnt = 0;
return;
}
/*
* Close archive file. This may take a LONG while on tapes (we may be
* forced to wait for the rewind to complete) so tell the user what is
* going on (this avoids the user hitting control-c thinking pax is
* broken).
*/
if (vflag && (artyp == ISTAPE)) {
if (vfpart)
(void)putc('\n', listf);
(void)fprintf(listf,
"%s: Waiting for tape drive close to complete...",
argv0);
(void)fflush(listf);
}
/*
* if nothing was written to the archive (and we created it), we remove
* it
*/
if (can_unlnk && (fstat(arfd, &arsb) == 0) && (S_ISREG(arsb.st_mode)) &&
(arsb.st_size == 0)) {
(void)unlink(arcname);
can_unlnk = 0;
}
/*
* for a quick extract/list, pax frequently exits before the child
* process is done
*/
if ((act == LIST || act == EXTRACT) && nflag && zpid > 0)
kill(zpid, SIGINT);
(void)close(arfd);
/* Do not exit before child to ensure data integrity */
if (zpid > 0)
waitpid(zpid, &status, 0);
if (vflag && (artyp == ISTAPE)) {
(void)fputs("done.\n", listf);
vfpart = 0;
(void)fflush(listf);
}
arfd = -1;
if (!io_ok && !did_io) {
flcnt = 0;
return;
}
did_io = io_ok = 0;
/*
* The volume number is only increased when the last device has data
* and we have already determined the archive format.
*/
if (frmt != NULL)
++arvol;
if (!vflag) {
flcnt = 0;
return;
}
/*
* Print out a summary of I/O for this archive volume.
*/
if (vfpart) {
(void)putc('\n', listf);
vfpart = 0;
}
/*
* If we have not determined the format yet, we just say how many bytes
* we have skipped over looking for a header to id. There is no way we
* could have written anything yet.
*/
if (frmt == NULL) {
# ifdef NET2_STAT
(void)fprintf(listf, "%s: unknown format, %lu bytes skipped.\n",
argv0, rdcnt);
# else
(void)fprintf(listf, "%s: unknown format, %ju bytes skipped.\n",
argv0, (uintmax_t)rdcnt);
# endif
(void)fflush(listf);
flcnt = 0;
return;
}
if (strcmp(NM_CPIO, argv0) == 0)
(void)fprintf(listf, "%llu blocks\n",
(unsigned long long)((rdcnt ? rdcnt : wrcnt) / 5120));
else if (strcmp(NM_TAR, argv0) != 0)
(void)fprintf(listf,
# ifdef NET2_STAT
"%s: %s vol %d, %lu files, %lu bytes read, %lu bytes written.\n",
argv0, frmt->name, arvol-1, flcnt, rdcnt, wrcnt);
# else
"%s: %s vol %d, %ju files, %ju bytes read, %ju bytes written.\n",
argv0, frmt->name, arvol-1, (uintmax_t)flcnt,
(uintmax_t)rdcnt, (uintmax_t)wrcnt);
# endif
(void)fflush(listf);
flcnt = 0;
}
/*
* ar_drain()
* drain any archive format independent padding from an archive read
* from a socket or a pipe. This is to prevent the process on the
* other side of the pipe from getting a SIGPIPE (pax will stop
* reading an archive once a format dependent trailer is detected).
*/
void
ar_drain(void)
{
int res;
char drbuf[MAXBLK];
/*
* we only drain from a pipe/socket. Other devices can be closed
* without reading up to end of file. We sure hope that pipe is closed
* on the other side so we will get an EOF.
*/
if ((artyp != ISPIPE) || (lstrval <= 0))
return;
/*
* keep reading until pipe is drained
*/
while ((res = read(arfd, drbuf, sizeof(drbuf))) > 0)
;
lstrval = res;
}
/*
* ar_set_wr()
* Set up device right before switching from read to write in an append.
* device dependent code (if required) to do this should be added here.
* For all archive devices we are already positioned at the place we want
* to start writing when this routine is called.
* Return:
* 0 if all ready to write, -1 otherwise
*/
int
ar_set_wr(void)
{
off_t cpos;
/*
* we must make sure the trailer is rewritten on append, ar_next()
* will stop us if the archive containing the trailer was not written
*/
wr_trail = 0;
/*
* Add any device dependent code as required here
*/
if (artyp != ISREG)
return(0);
/*
* Ok we have an archive in a regular file. If we were rewriting a
* file, we must get rid of all the stuff after the current offset
* (it was not written by pax).
*/
if (((cpos = lseek(arfd, (off_t)0L, SEEK_CUR)) < 0) ||
(ftruncate(arfd, cpos) < 0)) {
syswarn(1, errno, "Unable to truncate archive file");
return(-1);
}
return(0);
}
/*
* ar_app_ok()
* check if the last volume in the archive allows appends. We cannot check
* this until we are ready to write since there is no spec that says all
* volumes in a single archive have to be of the same type...
* Return:
* 0 if we can append, -1 otherwise.
*/
int
ar_app_ok(void)
{
if (artyp == ISPIPE) {
paxwarn(1, "Cannot append to an archive obtained from a pipe.");
return(-1);
}
if (!invld_rec)
return(0);
paxwarn(1,"Cannot append, device record size %d does not support %s spec",
rdblksz, argv0);
return(-1);
}
/*
* ar_read()
* read up to a specified number of bytes from the archive into the
* supplied buffer. When dealing with tapes we may not always be able to
* read what we want.
* Return:
* Number of bytes in buffer. 0 for end of file, -1 for a read error.
*/
int
ar_read(char *buf, int cnt)
{
int res = 0;
/*
* if last i/o was in error, no more reads until reset or new volume
*/
if (lstrval <= 0)
return(lstrval);
/*
* how we read must be based on device type
*/
switch (artyp) {
case ISTAPE:
if ((res = read(arfd, buf, cnt)) > 0) {
/*
* CAUTION: tape systems may not always return the same
* sized records so we leave blksz == MAXBLK. The
* physical record size that a tape drive supports is
* very hard to determine in a uniform and portable
* manner.
*/
io_ok = 1;
if (res != rdblksz) {
/*
* Record size changed. If this is happens on
* any record after the first, we probably have
* a tape drive which has a fixed record size
* we are getting multiple records in a single
* read). Watch out for record blocking that
* violates pax spec (must be a multiple of
* BLKMULT).
*/
rdblksz = res;
if (rdblksz % BLKMULT)
invld_rec = 1;
}
return(res);
}
break;
case ISREG:
case ISBLK:
case ISCHR:
case ISPIPE:
default:
/*
* Files are so easy to deal with. These other things cannot
* be trusted at all. So when we are dealing with character
* devices and pipes we just take what they have ready for us
* and return. Trying to do anything else with them runs the
* risk of failure.
*/
if ((res = read(arfd, buf, cnt)) > 0) {
io_ok = 1;
return(res);
}
break;
}
/*
* We are in trouble at this point, something is broken...
*/
lstrval = res;
if (res < 0)
syswarn(1, errno, "Failed read on archive volume %d", arvol);
else
paxwarn(0, "End of archive volume %d reached", arvol);
return(res);
}
/*
* ar_write()
* Write a specified number of bytes in supplied buffer to the archive
* device so it appears as a single "block". Deals with errors and tries
* to recover when faced with short writes.
* Return:
* Number of bytes written. 0 indicates end of volume reached and with no
* flaws (as best that can be detected). A -1 indicates an unrecoverable
* error in the archive occurred.
*/
int
ar_write(char *buf, int bsz)
{
int res;
off_t cpos;
/*
* do not allow pax to create a "bad" archive. Once a write fails on
* an archive volume prevent further writes to it.
*/
if (lstrval <= 0)
return(lstrval);
if ((res = write(arfd, buf, bsz)) == bsz) {
wr_trail = 1;
io_ok = 1;
return(bsz);
}
/*
* write broke, see what we can do with it. We try to send any partial
* writes that may violate pax spec to the next archive volume.
*/
if (res < 0)
lstrval = res;
else
lstrval = 0;
switch (artyp) {
case ISREG:
if ((res > 0) && (res % BLKMULT)) {
/*
* try to fix up partial writes which are not BLKMULT
* in size by forcing the runt record to next archive
* volume
*/
if ((cpos = lseek(arfd, (off_t)0L, SEEK_CUR)) < 0)
break;
cpos -= (off_t)res;
if (ftruncate(arfd, cpos) < 0)
break;
res = lstrval = 0;
break;
}
if (res >= 0)
break;
/*
* if file is out of space, handle it like a return of 0
*/
if ((errno == ENOSPC) || (errno == EFBIG) || (errno == EDQUOT))
res = lstrval = 0;
break;
case ISTAPE:
case ISCHR:
case ISBLK:
if (res >= 0)
break;
if (errno == EACCES) {
paxwarn(0, "Write failed, archive is write protected.");
res = lstrval = 0;
return(0);
}
/*
* see if we reached the end of media, if so force a change to
* the next volume
*/
if ((errno == ENOSPC) || (errno == EIO) || (errno == ENXIO))
res = lstrval = 0;
break;
case ISPIPE:
default:
/*
* we cannot fix errors to these devices
*/
break;
}
/*
* Better tell the user the bad news...
* if this is a block aligned archive format, we may have a bad archive
* if the format wants the header to start at a BLKMULT boundary. While
* we can deal with the mis-aligned data, it violates spec and other
* archive readers will likely fail. If the format is not block
* aligned, the user may be lucky (and the archive is ok).
*/
if (res >= 0) {
if (res > 0)
wr_trail = 1;
io_ok = 1;
}
/*
* If we were trying to rewrite the trailer and it didn't work, we
* must quit right away.
*/
if (!wr_trail && (res <= 0)) {
paxwarn(1,"Unable to append, trailer re-write failed. Quitting.");
return(res);
}
if (res == 0)
paxwarn(0, "End of archive volume %d reached", arvol);
else if (res < 0)
syswarn(1, errno, "Failed write to archive volume: %d", arvol);
else if (!frmt->blkalgn || ((res % frmt->blkalgn) == 0))
paxwarn(0,"WARNING: partial archive write. Archive MAY BE FLAWED");
else
paxwarn(1,"WARNING: partial archive write. Archive IS FLAWED");
return(res);
}
/*
* ar_rdsync()
* Try to move past a bad spot on a flawed archive as needed to continue
* I/O. Clears error flags to allow I/O to continue.
* Return:
* 0 when ok to try i/o again, -1 otherwise.
*/
int
ar_rdsync(void)
{
long fsbz;
off_t cpos;
off_t mpos;
struct mtop mb;
/*
* Fail resync attempts at user request (done) or this is going to be
* an update/append to an existing archive. If last i/o hit media end,
* we need to go to the next volume not try a resync.
*/
if ((done > 0) || (lstrval == 0))
return(-1);
if ((act == APPND) || (act == ARCHIVE)) {
paxwarn(1, "Cannot allow updates to an archive with flaws.");
return(-1);
}
if (io_ok)
did_io = 1;
switch(artyp) {
case ISTAPE:
/*
* if the last i/o was a successful data transfer, we assume
* the fault is just a bad record on the tape that we are now
* past. If we did not get any data since the last resync try
* to move the tape forward one PHYSICAL record past any
* damaged tape section. Some tape drives are stubborn and need
* to be pushed.
*/
if (io_ok) {
io_ok = 0;
lstrval = 1;
break;
}
mb.mt_op = MTFSR;
mb.mt_count = 1;
if (ioctl(arfd, MTIOCTOP, &mb) < 0)
break;
lstrval = 1;
break;
case ISREG:
case ISCHR:
case ISBLK:
/*
* try to step over the bad part of the device.
*/
io_ok = 0;
if (((fsbz = arsb.st_blksize) <= 0) || (artyp != ISREG))
fsbz = BLKMULT;
if ((cpos = lseek(arfd, (off_t)0L, SEEK_CUR)) < 0)
break;
mpos = fsbz - (cpos % (off_t)fsbz);
if (lseek(arfd, mpos, SEEK_CUR) < 0)
break;
lstrval = 1;
break;
case ISPIPE:
default:
/*
* cannot recover on these archive device types
*/
io_ok = 0;
break;
}
if (lstrval <= 0) {
paxwarn(1, "Unable to recover from an archive read failure.");
return(-1);
}
paxwarn(0, "Attempting to recover from an archive read failure.");
return(0);
}
/*
* ar_fow()
* Move the I/O position within the archive forward the specified number of
* bytes as supported by the device. If we cannot move the requested
* number of bytes, return the actual number of bytes moved in skipped.
* Return:
* 0 if moved the requested distance, -1 on complete failure, 1 on
* partial move (the amount moved is in skipped)
*/
int
ar_fow(off_t sksz, off_t *skipped)
{
off_t cpos;
off_t mpos;
*skipped = 0;
if (sksz <= 0)
return(0);
/*
* we cannot move forward at EOF or error
*/
if (lstrval <= 0)
return(lstrval);
/*
* Safer to read forward on devices where it is hard to find the end of
* the media without reading to it. With tapes we cannot be sure of the
* number of physical blocks to skip (we do not know physical block
* size at this point), so we must only read forward on tapes!
*/
if (artyp != ISREG)
return(0);
/*
* figure out where we are in the archive
*/
if ((cpos = lseek(arfd, (off_t)0L, SEEK_CUR)) >= 0) {
/*
* we can be asked to move farther than there are bytes in this
* volume, if so, just go to file end and let normal buf_fill()
* deal with the end of file (it will go to next volume by
* itself)
*/
if ((mpos = cpos + sksz) > arsb.st_size) {
*skipped = arsb.st_size - cpos;
mpos = arsb.st_size;
} else
*skipped = sksz;
if (lseek(arfd, mpos, SEEK_SET) >= 0)
return(0);
}
syswarn(1, errno, "Forward positioning operation on archive failed");
lstrval = -1;
return(-1);
}
/*
* ar_rev()
* move the i/o position within the archive backwards the specified byte
* count as supported by the device. With tapes drives we RESET rdblksz to
* the PHYSICAL blocksize.
* NOTE: We should only be called to move backwards so we can rewrite the
* last records (the trailer) of an archive (APPEND).
* Return:
* 0 if moved the requested distance, -1 on complete failure
*/
int
ar_rev(off_t sksz)
{
off_t cpos;
struct mtop mb;
int phyblk;
/*
* make sure we do not have try to reverse on a flawed archive
*/
if (lstrval < 0)
return(lstrval);
switch(artyp) {
case ISPIPE:
if (sksz <= 0)
break;
/*
* cannot go backwards on these critters
*/
paxwarn(1, "Reverse positioning on pipes is not supported.");
lstrval = -1;
return(-1);
case ISREG:
case ISBLK:
case ISCHR:
default:
if (sksz <= 0)
break;
/*
* For things other than files, backwards movement has a very
* high probability of failure as we really do not know the
* true attributes of the device we are talking to (the device
* may not even have the ability to lseek() in any direction).
* First we figure out where we are in the archive.
*/
if ((cpos = lseek(arfd, (off_t)0L, SEEK_CUR)) < 0) {
syswarn(1, errno,
"Unable to obtain current archive byte offset");
lstrval = -1;
return(-1);
}
/*
* we may try to go backwards past the start when the archive
* is only a single record. If this happens and we are on a
* multi volume archive, we need to go to the end of the
* previous volume and continue our movement backwards from
* there.
*/
if ((cpos -= sksz) < (off_t)0L) {
if (arvol > 1) {
/*
* this should never happen
*/
paxwarn(1,"Reverse position on previous volume.");
lstrval = -1;
return(-1);
}
cpos = (off_t)0L;
}
if (lseek(arfd, cpos, SEEK_SET) < 0) {
syswarn(1, errno, "Unable to seek archive backwards");
lstrval = -1;
return(-1);
}
break;
case ISTAPE:
/*
* Calculate and move the proper number of PHYSICAL tape
* blocks. If the sksz is not an even multiple of the physical
* tape size, we cannot do the move (this should never happen).
* (We also cannot handler trailers spread over two vols).
* get_phys() also makes sure we are in front of the filemark.
*/
if ((phyblk = get_phys()) <= 0) {
lstrval = -1;
return(-1);
}
/*
* make sure future tape reads only go by physical tape block
* size (set rdblksz to the real size).
*/
rdblksz = phyblk;
/*
* if no movement is required, just return (we must be after
* get_phys() so the physical blocksize is properly set)
*/
if (sksz <= 0)
break;
/*
* ok we have to move. Make sure the tape drive can do it.
*/
if (sksz % phyblk) {
paxwarn(1,
"Tape drive unable to backspace requested amount");
lstrval = -1;
return(-1);
}
/*
* move backwards the requested number of bytes
*/
mb.mt_op = MTBSR;
mb.mt_count = sksz/phyblk;
if (ioctl(arfd, MTIOCTOP, &mb) < 0) {
syswarn(1,errno, "Unable to backspace tape %d blocks.",
mb.mt_count);
lstrval = -1;
return(-1);
}
break;
}
lstrval = 1;
return(0);
}
/*
* get_phys()
* Determine the physical block size on a tape drive. We need the physical
* block size so we know how many bytes we skip over when we move with
* mtio commands. We also make sure we are BEFORE THE TAPE FILEMARK when
* return.
* This is one really SLOW routine...
* Return:
* physical block size if ok (ok > 0), -1 otherwise
*/
static int
get_phys(void)
{
int padsz = 0;
int res;
int phyblk;
struct mtop mb;
char scbuf[MAXBLK];
/*
* move to the file mark, and then back up one record and read it.
* this should tell us the physical record size the tape is using.
*/
if (lstrval == 1) {
/*
* we know we are at file mark when we get back a 0 from
* read()
*/
while ((res = read(arfd, scbuf, sizeof(scbuf))) > 0)
padsz += res;
if (res < 0) {
syswarn(1, errno, "Unable to locate tape filemark.");
return(-1);
}
}
/*
* move backwards over the file mark so we are at the end of the
* last record.
*/
mb.mt_op = MTBSF;
mb.mt_count = 1;
if (ioctl(arfd, MTIOCTOP, &mb) < 0) {
syswarn(1, errno, "Unable to backspace over tape filemark.");
return(-1);
}
/*
* move backwards so we are in front of the last record and read it to
* get physical tape blocksize.
*/
mb.mt_op = MTBSR;
mb.mt_count = 1;
if (ioctl(arfd, MTIOCTOP, &mb) < 0) {
syswarn(1, errno, "Unable to backspace over last tape block.");
return(-1);
}
if ((phyblk = read(arfd, scbuf, sizeof(scbuf))) <= 0) {
syswarn(1, errno, "Cannot determine archive tape blocksize.");
return(-1);
}
/*
* read forward to the file mark, then back up in front of the filemark
* (this is a bit paranoid, but should be safe to do).
*/
while ((res = read(arfd, scbuf, sizeof(scbuf))) > 0)
;
if (res < 0) {
syswarn(1, errno, "Unable to locate tape filemark.");
return(-1);
}
mb.mt_op = MTBSF;
mb.mt_count = 1;
if (ioctl(arfd, MTIOCTOP, &mb) < 0) {
syswarn(1, errno, "Unable to backspace over tape filemark.");
return(-1);
}
/*
* set lstrval so we know that the filemark has not been seen
*/
lstrval = 1;
/*
* return if there was no padding
*/
if (padsz == 0)
return(phyblk);
/*
* make sure we can move backwards over the padding. (this should
* never fail).
*/
if (padsz % phyblk) {
paxwarn(1, "Tape drive unable to backspace requested amount");
return(-1);
}
/*
* move backwards over the padding so the head is where it was when
* we were first called (if required).
*/
mb.mt_op = MTBSR;
mb.mt_count = padsz/phyblk;
if (ioctl(arfd, MTIOCTOP, &mb) < 0) {
syswarn(1,errno,"Unable to backspace tape over %d pad blocks",
mb.mt_count);
return(-1);
}
return(phyblk);
}
/*
* ar_next()
* prompts the user for the next volume in this archive. For some devices
* we may allow the media to be changed. Otherwise a new archive is
* prompted for. By pax spec, if there is no controlling tty or an eof is
* read on tty input, we must quit pax.
* Return:
* 0 when ready to continue, -1 when all done
*/
int
ar_next(void)
{
static char *arcbuf;
char buf[PAXPATHLEN+2];
sigset_t o_mask;
/*
* WE MUST CLOSE THE DEVICE. A lot of devices must see last close, (so
* things like writing EOF etc will be done) (Watch out ar_close() can
* also be called via a signal handler, so we must prevent a race.
*/
if (sigprocmask(SIG_BLOCK, &s_mask, &o_mask) < 0)
syswarn(0, errno, "Unable to set signal mask");
ar_close();
if (sigprocmask(SIG_SETMASK, &o_mask, NULL) < 0)
syswarn(0, errno, "Unable to restore signal mask");
if (done || !wr_trail || Oflag || strcmp(NM_TAR, argv0) == 0)
return(-1);
tty_prnt("\nATTENTION! %s archive volume change required.\n", argv0);
/*
* if i/o is on stdin or stdout, we cannot reopen it (we do not know
* the name), the user will be forced to type it in.
*/
if (strcmp(arcname, stdo) && strcmp(arcname, stdn) && (artyp != ISREG)
&& (artyp != ISPIPE)) {
if (artyp == ISTAPE) {
tty_prnt("%s ready for archive tape volume: %d\n",
arcname, arvol);
tty_prnt("Load the NEXT TAPE on the tape drive");
} else {
tty_prnt("%s ready for archive volume: %d\n",
arcname, arvol);
tty_prnt("Load the NEXT STORAGE MEDIA (if required)");
}
if ((act == ARCHIVE) || (act == APPND))
tty_prnt(" and make sure it is WRITE ENABLED.\n");
else
tty_prnt("\n");
for(;;) {
tty_prnt("Type \"y\" to continue, \".\" to quit %s,",
argv0);
tty_prnt(" or \"s\" to switch to new device.\nIf you");
tty_prnt(" cannot change storage media, type \"s\"\n");
tty_prnt("Is the device ready and online? > ");
if ((tty_read(buf,sizeof(buf))<0) || !strcmp(buf,".")){
done = 1;
lstrval = -1;
tty_prnt("Quitting %s!\n", argv0);
vfpart = 0;
return(-1);
}
if ((buf[0] == '\0') || (buf[1] != '\0')) {
tty_prnt("%s unknown command, try again\n",buf);
continue;
}
switch (buf[0]) {
case 'y':
case 'Y':
/*
* we are to continue with the same device
*/
if (ar_open(arcname) >= 0)
return(0);
tty_prnt("Cannot re-open %s, try again\n",
arcname);
continue;
case 's':
case 'S':
/*
* user wants to open a different device
*/
tty_prnt("Switching to a different archive\n");
break;
default:
tty_prnt("%s unknown command, try again\n",buf);
continue;
}
break;
}
} else
tty_prnt("Ready for archive volume: %d\n", arvol);
/*
* have to go to a different archive
*/
for (;;) {
tty_prnt("Input archive name or \".\" to quit %s.\n", argv0);
tty_prnt("Archive name > ");
if ((tty_read(buf, sizeof(buf)) < 0) || !strcmp(buf, ".")) {
done = 1;
lstrval = -1;
tty_prnt("Quitting %s!\n", argv0);
vfpart = 0;
return(-1);
}
if (buf[0] == '\0') {
tty_prnt("Empty file name, try again\n");
continue;
}
if (!strcmp(buf, "..")) {
tty_prnt("Illegal file name: .. try again\n");
continue;
}
if (strlen(buf) > PAXPATHLEN) {
tty_prnt("File name too long, try again\n");
continue;
}
/*
* try to open new archive
*/
if (ar_open(buf) >= 0) {
free(arcbuf);
if ((arcbuf = strdup(buf)) == NULL) {
done = 1;
lstrval = -1;
paxwarn(0, "Cannot save archive name.");
return(-1);
}
arcname = arcbuf;
break;
}
tty_prnt("Cannot open %s, try again\n", buf);
continue;
}
return(0);
}
/*
* ar_start_gzip()
* starts the gzip compression/decompression process as a child, using magic
* to keep the fd the same in the calling function (parent).
*/
void
ar_start_gzip(int fd, const char *gzip_prog, int wr)
{
int fds[2];
const char *gzip_flags;
if (pipe(fds) < 0)
err(1, "could not pipe");
zpid = fork();
if (zpid < 0)
err(1, "could not fork");
/* parent */
if (zpid) {
if (wr)
dup2(fds[1], fd);
else
dup2(fds[0], fd);
close(fds[0]);
close(fds[1]);
} else {
if (wr) {
dup2(fds[0], STDIN_FILENO);
dup2(fd, STDOUT_FILENO);
gzip_flags = "-c";
} else {
dup2(fds[1], STDOUT_FILENO);
dup2(fd, STDIN_FILENO);
gzip_flags = "-dc";
}
close(fds[0]);
close(fds[1]);
if (execlp(gzip_prog, gzip_prog, gzip_flags,
(char *)NULL) < 0)
err(1, "could not exec");
/* NOTREACHED */
}
}