ar_io.c

早期freebsd实现

/*-
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 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
static char sccsid[] = "@(#)ar_io.c	8.2 (Berkeley) 4/18/94";
#endif /* not lint */

#include <sys/types.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/mtio.h>
#include <sys/param.h>
#include <signal.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <ctype.h>
#include <errno.h>
#include <stdlib.h>
#include "pax.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 */
#define STDO		"<STDOUT>"	/* psuedo name for stdout */
#define STDN		"<STDIN>"	/* psuedo 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?  */
char *arcname;                  	/* printable name of archive */

static int get_phys __P((void));
extern sigset_t s_mask;

/*
 * 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
 */

#if __STDC__
int
ar_open(char *name)
#else
int
ar_open(name)
	char *name;
#endif
{
        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);
		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;
		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);

	/*
	 * 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)) {
		warn(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, otherwize 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 cannont 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
 */
#if __STDC__
void
ar_close(void)
#else
void
ar_close()
#endif
{
	FILE *outf;

	if (arfd < 0) {
		did_io = io_ok = flcnt = 0;
		return;
	}

	if (act == LIST)
		outf = stdout;
	else
		outf = stderr;

	/*
	 * 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', outf);
		(void)fprintf(outf,
			"%s: Waiting for tape drive close to complete...",
			argv0);
		(void)fflush(outf);
	}

	/*
	 * 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;
	}

	(void)close(arfd);

	if (vflag && (artyp == ISTAPE)) {
		(void)fputs("done.\n", outf);
		vfpart = 0;
		(void)fflush(outf);
	}
	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', outf);
		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(outf, "%s: unknown format, %lu bytes skipped.\n",
#	else
		(void)fprintf(outf, "%s: unknown format, %qu bytes skipped.\n",
#	endif
		    argv0, rdcnt);
		(void)fflush(outf);
		flcnt = 0;
		return;
	}

	(void)fprintf(outf,
#	ifdef NET2_STAT
	    "%s: %s vol %d, %lu files, %lu bytes read, %lu bytes written.\n",
#	else
	    "%s: %s vol %d, %lu files, %qu bytes read, %qu bytes written.\n",
#	endif
	    argv0, frmt->name, arvol-1, flcnt, rdcnt, wrcnt);
	(void)fflush(outf);
	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).
 */
#if __STDC__
void
ar_drain(void)
#else
void
ar_drain()
#endif
{
	register 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)
		;