Subversion Repositories planix.SVN

/* $Source: /u/mark/src/pax/RCS/extract.c,v $

 *

 * $Revision: 1.3 $

 *

 * extract.c - Extract files from a tar archive. 

 *

 * DESCRIPTION

 *

 * AUTHOR

 *

 *	Mark H. Colburn, NAPS International (mark@jhereg.mn.org)

 *

 * Sponsored by The USENIX Association for public distribution. 

 *

 * Copyright (c) 1989 Mark H. Colburn.

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms are permitted

 * provided that the above copyright notice is duplicated in all such 

 * forms and that any documentation, advertising materials, and other 

 * materials related to such distribution and use acknowledge that the 

 * software was developed * by Mark H. Colburn and sponsored by The 

 * USENIX Association. 

 *

 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED

 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

 *

 * $Log:	extract.c,v $

 * Revision 1.3  89/02/12  10:29:43  mark

 * Fixed misspelling of Replstr

 * 

 * Revision 1.2  89/02/12  10:04:24  mark

 * 1.2 release fixes

 * 

 * Revision 1.1  88/12/23  18:02:07  mark

 * Initial revision

 * 

 */

#ifndef lint

static char *ident = "$Id: extract.c,v 1.3 89/02/12 10:29:43 mark Exp Locker: mark $";

static char *copyright = "Copyright (c) 1989 Mark H. Colburn.\nAll rights reserved.\n";

#endif /* ! lint */

/* Headers */

#include "pax.h"

/* Defines */

/*

 * Swap bytes. 

 */

#define	SWAB(n)	((((ushort)(n) >> 8) & 0xff) | (((ushort)(n) << 8) & 0xff00))

/* Function Prototypes */

#ifdef __STDC__

static int inbinary(char *, char *, Stat *);

static int inascii(char *, char *, Stat *);

static int inswab(char *, char *, Stat *);

static int readtar(char *, Stat *);

static int readcpio(char *, Stat *);

#else /* !__STDC__ */

static int inbinary();

static int inascii();

static int inswab();

static int readtar();

static int readcpio();

#endif /* __STDC__ */

/* read_archive - read in an archive

 *

 * DESCRIPTION

 *

 *	Read_archive is the central entry point for reading archives.

 *	Read_archive determines the proper archive functions to call

 *	based upon the archive type being processed.

 *

 * RETURNS

 *

 */

#ifdef __STDC__

int read_archive(void)

#else

int read_archive()

#endif

{

    Stat            sb;

    char            name[PATH_MAX + 1];

    int             match;

    int		    pad;

    name_gather();		/* get names from command line */

    name[0] = '\0';

    while (get_header(name, &sb) == 0) {

	match = name_match(name) ^ f_reverse_match;

	if (f_list) {		/* only wanted a table of contents */

	    if (match) {

		print_entry(name, &sb);

	    }

	    if (((ar_format == TAR) 

		? buf_skip(ROUNDUP((OFFSET) sb.sb_size, BLOCKSIZE)) 

		: buf_skip((OFFSET) sb.sb_size)) < 0) {

		warn(name, "File data is corrupt");

	    }

	} else if (match) {

	    if (rplhead != (Replstr *)NULL) {

		rpl_name(name);

		if (strlen(name) == 0) {

		    continue;

		}

	    }

	    if (get_disposition("extract", name) || 

                get_newname(name, sizeof(name))) {

		/* skip file... */

		if (((ar_format == TAR) 

		    ? buf_skip(ROUNDUP((OFFSET) sb.sb_size, BLOCKSIZE)) 

		    : buf_skip((OFFSET) sb.sb_size)) < 0) {

		    warn(name, "File data is corrupt");

		}

		continue;

	    } 

	    if (inentry(name, &sb) < 0) {

		warn(name, "File data is corrupt");

	    }

	    if (f_verbose) {

		print_entry(name, &sb);

	    }

	    if (ar_format == TAR && sb.sb_nlink > 1) {

		/*

		 * This kludge makes sure that the link table is cleared

		 * before attempting to process any other links.

		 */

		if (sb.sb_nlink > 1) {

		    linkfrom(name, &sb);

		}

	    }

	    if (ar_format == TAR && (pad = sb.sb_size % BLOCKSIZE) != 0) {

		pad = BLOCKSIZE - pad;

		buf_skip((OFFSET) pad);

	    }

	} else {

	    if (((ar_format == TAR) 

		? buf_skip(ROUNDUP((OFFSET) sb.sb_size, BLOCKSIZE)) 

		: buf_skip((OFFSET) sb.sb_size)) < 0) {

		warn(name, "File data is corrupt");

	    }

	}

    }

    close_archive();

}

/* get_header - figures which type of header needs to be read.

 *

 * DESCRIPTION

 *

 *	This is merely a single entry point for the two types of archive

 *	headers which are supported.  The correct header is selected

 *	depending on the archive type.

 *

 * PARAMETERS

 *

 *	char	*name	- name of the file (passed to header routine)

 *	Stat	*asb	- Stat block for the file (passed to header routine)

 *

 * RETURNS

 *

 *	Returns the value which was returned by the proper header

 *	function.

 */

#ifdef __STDC__

int get_header(char *name, Stat *asb)

#else

int get_header(name, asb)

char *name;

Stat *asb;

#endif

{

    if (ar_format == TAR) {

	return(readtar(name, asb));

    } else {

	return(readcpio(name, asb));

    }

}

/* readtar - read a tar header

 *

 * DESCRIPTION

 *

 *	Tar_head read a tar format header from the archive.  The name

 *	and asb parameters are modified as appropriate for the file listed

 *	in the header.   Name is assumed to be a pointer to an array of

 *	at least PATH_MAX bytes.

 *

 * PARAMETERS

 *

 *	char	*name 	- name of the file for which the header is

 *			  for.  This is modified and passed back to

 *			  the caller.

 *	Stat	*asb	- Stat block for the file for which the header

 *			  is for.  The fields of the stat structure are

 *			  extracted from the archive header.  This is

 *			  also passed back to the caller.

 *

 * RETURNS

 *

 *	Returns 0 if a valid header was found, or -1 if EOF is

 *	encountered.

 */

#ifdef __STDC__

static int readtar(char *name, Stat *asb)

#else

static int readtar(name, asb)

char	*name;

Stat    *asb;

#endif

{

    int             status = 3;	/* Initial status at start of archive */

    static int      prev_status;

    for (;;) {

	prev_status = status;

	status = read_header(name, asb);

	switch (status) {

	case 1:		/* Valid header */

		return(0);

	case 0:		/* Invalid header */

	    switch (prev_status) {

	    case 3:		/* Error on first record */

		warn(ar_file, "This doesn't look like a tar archive");

		/* FALLTHRU */

	    case 2:		/* Error after record of zeroes */

	    case 1:		/* Error after header rec */

		warn(ar_file, "Skipping to next file...");

		/* FALLTHRU */

	    default:

	    case 0:		/* Error after error */

		break;

	    }

	    break;

	case 2:			/* Record of zeroes */

	case EOF:		/* End of archive */

	default:

	    return(-1);

	}

    }

}

/* readcpio - read a CPIO header 

 *

 * DESCRIPTION

 *

 *	Read in a cpio header.  Understands how to determine and read ASCII, 

 *	binary and byte-swapped binary headers.  Quietly translates 

 *	old-fashioned binary cpio headers (and arranges to skip the possible 

 *	alignment byte). Returns zero if successful, -1 upon archive trailer. 

 *

 * PARAMETERS

 *

 *	char	*name 	- name of the file for which the header is

 *			  for.  This is modified and passed back to

 *			  the caller.

 *	Stat	*asb	- Stat block for the file for which the header

 *			  is for.  The fields of the stat structure are

 *			  extracted from the archive header.  This is

 *			  also passed back to the caller.

 *

 * RETURNS

 *

 *	Returns 0 if a valid header was found, or -1 if EOF is

 *	encountered.

 */

#ifdef __STDC__

static int readcpio(char *name, Stat *asb)

#else

static int readcpio(name, asb)

char           *name;

Stat           *asb;

#endif

{

    OFFSET          skipped;

    char            magic[M_STRLEN];

    static int      align;

    if (align > 0) {

	buf_skip((OFFSET) align);

    }

    align = 0;

    for (;;) {

	buf_read(magic, M_STRLEN);

	skipped = 0;

	while ((align = inascii(magic, name, asb)) < 0

	       && (align = inbinary(magic, name, asb)) < 0

	       && (align = inswab(magic, name, asb)) < 0) {

	    if (++skipped == 1) {

		if (total - sizeof(magic) == 0) {

		    fatal("Unrecognizable archive");

		}

		warnarch("Bad magic number", (OFFSET) sizeof(magic));

		if (name[0]) {

		    warn(name, "May be corrupt");

		}

	    }

	    memcpy(magic, magic + 1, sizeof(magic) - 1);

	    buf_read(magic + sizeof(magic) - 1, 1);

	}

	if (skipped) {

	    warnarch("Apparently resynchronized", (OFFSET) sizeof(magic));

	    warn(name, "Continuing");

	}

	if (strcmp(name, TRAILER) == 0) {

	    return (-1);

	}

	if (nameopt(name) >= 0) {

	    break;

	}

	buf_skip((OFFSET) asb->sb_size + align);

    }

#ifdef	S_IFLNK

    if ((asb->sb_mode & S_IFMT) == S_IFLNK) {

	if (buf_read(asb->sb_link, (uint) asb->sb_size) < 0) {

	    warn(name, "Corrupt symbolic link");

	    return (readcpio(name, asb));

	}

	asb->sb_link[asb->sb_size] = '\0';

	asb->sb_size = 0;

    }

#endif				/* S_IFLNK */

    /* destroy absolute pathnames for security reasons */

    if (name[0] == '/') {

	if (name[1]) {

	    while (name[0] = name[1]) {

		++name;

	    }

	} else {

	    name[0] = '.';

	}

    }

    asb->sb_atime = asb->sb_ctime = asb->sb_mtime;

    if (asb->sb_nlink > 1) {

	linkto(name, asb);

    }

    return (0);

}

/* inswab - read a reversed by order binary header

 *

 * DESCRIPTIONS

 *

 *	Reads a byte-swapped CPIO binary archive header

 *

 * PARMAMETERS

 *

 *	char	*magic	- magic number to match

 *	char	*name	- name of the file which is stored in the header.

 *			  (modified and passed back to caller).

 *	Stat	*asb	- stat block for the file (modified and passed back

 *			  to the caller).

 *

 *

 * RETURNS

 *

 * 	Returns the number of trailing alignment bytes to skip; -1 if 

 *	unsuccessful. 

 *

 */

#ifdef __STDC__

static int inswab(char *magic, char *name, Stat *asb)

#else

static int inswab(magic, name, asb)

char           *magic;

char           *name;

Stat           *asb;

#endif

{

    ushort          namesize;

    uint            namefull;

    Binary          binary;

    if (*((ushort *) magic) != SWAB(M_BINARY)) {

	return (-1);

    }

    memcpy((char *) &binary,

		  magic + sizeof(ushort),

		  M_STRLEN - sizeof(ushort));

    if (buf_read((char *) &binary + M_STRLEN - sizeof(ushort),

		 sizeof(binary) - (M_STRLEN - sizeof(ushort))) < 0) {

	warnarch("Corrupt swapped header",

		 (OFFSET) sizeof(binary) - (M_STRLEN - sizeof(ushort)));

	return (-1);

    }

    asb->sb_dev = (dev_t) SWAB(binary.b_dev);

    asb->sb_ino = (ino_t) SWAB(binary.b_ino);

    asb->sb_mode = SWAB(binary.b_mode);

    asb->sb_uid = SWAB(binary.b_uid);

    asb->sb_gid = SWAB(binary.b_gid);

    asb->sb_nlink = SWAB(binary.b_nlink);

#ifndef _POSIX_SOURCE

    asb->sb_rdev = (dev_t) SWAB(binary.b_rdev);

#endif

    asb->sb_mtime = SWAB(binary.b_mtime[0]) << 16 | SWAB(binary.b_mtime[1]);

    asb->sb_size = SWAB(binary.b_size[0]) << 16 | SWAB(binary.b_size[1]);

    if ((namesize = SWAB(binary.b_name)) == 0 || namesize >= PATH_MAX) {

	warnarch("Bad swapped pathname length",

		 (OFFSET) sizeof(binary) - (M_STRLEN - sizeof(ushort)));

	return (-1);

    }

    if (buf_read(name, namefull = namesize + namesize % 2) < 0) {

	warnarch("Corrupt swapped pathname", (OFFSET) namefull);

	return (-1);

    }

    if (name[namesize - 1] != '\0') {

	warnarch("Bad swapped pathname", (OFFSET) namefull);

	return (-1);

    }

    return (asb->sb_size % 2);

}

/* inascii - read in an ASCII cpio header

 *

 * DESCRIPTION

 *

 *	Reads an ASCII format cpio header

 *

 * PARAMETERS

 *

 *	char	*magic	- magic number to match

 *	char	*name	- name of the file which is stored in the header.

 *			  (modified and passed back to caller).

 *	Stat	*asb	- stat block for the file (modified and passed back

 *			  to the caller).

 *

 * RETURNS

 *

 * 	Returns zero if successful; -1 otherwise. Assumes that  the entire 

 *	magic number has been read. 

 */

#ifdef __STDC__

static int inascii(char *magic, char *name, Stat *asb)

#else

static int inascii(magic, name, asb)

char           *magic;

char           *name;

Stat           *asb;

#endif

{

    uint            namelen;

    char            header[H_STRLEN + 1];

#ifdef _POSIX_SOURCE

    dev_t	    dummyrdev;

#endif

    if (strncmp(magic, M_ASCII, M_STRLEN) != 0) {

	return (-1);

    }

    if (buf_read(header, H_STRLEN) < 0) {

	warnarch("Corrupt ASCII header", (OFFSET) H_STRLEN);

	return (-1);

    }

    header[H_STRLEN] = '\0';

    if (sscanf(header, H_SCAN, &asb->sb_dev,

	       &asb->sb_ino, &asb->sb_mode, &asb->sb_uid,

#ifdef _POSIX_SOURCE

	       &asb->sb_gid, &asb->sb_nlink, &dummyrdev,

#else

	       &asb->sb_gid, &asb->sb_nlink, &asb->sb_rdev,

#endif

	       &asb->sb_mtime, &namelen, &asb->sb_size) != H_COUNT) {

	warnarch("Bad ASCII header", (OFFSET) H_STRLEN);

	return (-1);

    }

    if (namelen == 0 || namelen >= PATH_MAX) {

	warnarch("Bad ASCII pathname length", (OFFSET) H_STRLEN);

	return (-1);

    }

    if (buf_read(name, namelen) < 0) {

	warnarch("Corrupt ASCII pathname", (OFFSET) namelen);

	return (-1);

    }

    if (name[namelen - 1] != '\0') {

	warnarch("Bad ASCII pathname", (OFFSET) namelen);

	return (-1);

    }

    return (0);

}

/* inbinary - read a binary header

 *

 * DESCRIPTION

 *

 *	Reads a CPIO format binary header.

 *

 * PARAMETERS

 *

 *	char	*magic	- magic number to match

 *	char	*name	- name of the file which is stored in the header.

 *			  (modified and passed back to caller).

 *	Stat	*asb	- stat block for the file (modified and passed back

 *			  to the caller).

 *

 * RETURNS

 *

 * 	Returns the number of trailing alignment bytes to skip; -1 if 

 *	unsuccessful. 

 */

#ifdef __STDC__

static int inbinary(char *magic, char *name, Stat *asb)

#else

static int inbinary(magic, name, asb)

char           *magic;

char           *name;

Stat           *asb;

#endif

{

    uint            namefull;

    Binary          binary;

    if (*((ushort *) magic) != M_BINARY) {

	return (-1);

    }

    memcpy((char *) &binary,

		  magic + sizeof(ushort),

		  M_STRLEN - sizeof(ushort));

    if (buf_read((char *) &binary + M_STRLEN - sizeof(ushort),

		 sizeof(binary) - (M_STRLEN - sizeof(ushort))) < 0) {

	warnarch("Corrupt binary header",

		 (OFFSET) sizeof(binary) - (M_STRLEN - sizeof(ushort)));

	return (-1);

    }

    asb->sb_dev = binary.b_dev;

    asb->sb_ino = binary.b_ino;

    asb->sb_mode = binary.b_mode;

    asb->sb_uid = binary.b_uid;

    asb->sb_gid = binary.b_gid;

    asb->sb_nlink = binary.b_nlink;

#ifndef _POSIX_SOURCE

    asb->sb_rdev = binary.b_rdev;

#endif

    asb->sb_mtime = binary.b_mtime[0] << 16 | binary.b_mtime[1];

    asb->sb_size = binary.b_size[0] << 16 | binary.b_size[1];

    if (binary.b_name == 0 || binary.b_name >= PATH_MAX) {

	warnarch("Bad binary pathname length",

		 (OFFSET) sizeof(binary) - (M_STRLEN - sizeof(ushort)));

	return (-1);

    }

    if (buf_read(name, namefull = binary.b_name + binary.b_name % 2) < 0) {

	warnarch("Corrupt binary pathname", (OFFSET) namefull);

	return (-1);

    }

    if (name[binary.b_name - 1] != '\0') {

	warnarch("Bad binary pathname", (OFFSET) namefull);

	return (-1);

    }

    return (asb->sb_size % 2);

}