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| Current File : //usr/src/bin/pax/ar_io.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.
* 4. 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: release/9.1.0/bin/pax/ar_io.c 222177 2011-05-22 14:03:38Z uqs $");
#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);
extern sigset_t s_mask;
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 || 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 */
}
}