tar.c

早期freebsd实现

	default:
		break;
	}

	/*
	 * check file name len, remember extra char for dirs (the / at the end)
	 */
	len = arcn->nlen;
	if (arcn->type == PAX_DIR)
		++len;
	if (len > sizeof(hd->name)) {
		warn(1, "File name too long for tar %s", arcn->name);
		return(1);
	}

	/*
	 * copy the data out of the ARCHD into the tar header based on the type
	 * of the file. Remember many tar readers want the unused fields to be
	 * padded with zero. We set the linkflag field (type), the linkname
	 * (or zero if not used),the size, and set the padding (if any) to be
	 * added after the file data (0 for all other types, as they only have
	 * a header)
	 */
	hd = (HD_TAR *)hdblk;
	zf_strncpy(hd->name, arcn->name, sizeof(hd->name));
	arcn->pad = 0;

	if (arcn->type == PAX_DIR) {
		/*
		 * directories are the same as files, except have a filename
		 * that ends with a /, we add the slash here. No data follows,
		 * dirs, so no pad.
		 */
		hd->linkflag = AREGTYPE;
		bzero(hd->linkname, sizeof(hd->linkname));
		hd->name[len-1] = '/';
		if (ul_oct((u_long)0L, hd->size, sizeof(hd->size), 1))
			goto out;
	} else if (arcn->type == PAX_SLK) {
		/*
		 * no data follows this file, so no pad
		 */
		hd->linkflag = SYMTYPE;
		zf_strncpy(hd->linkname,arcn->ln_name, sizeof(hd->linkname));
		if (ul_oct((u_long)0L, hd->size, sizeof(hd->size), 1))
			goto out;
	} else if ((arcn->type == PAX_HLK) || (arcn->type == PAX_HRG)) {
		/*
		 * no data follows this file, so no pad
		 */
		hd->linkflag = LNKTYPE;
		zf_strncpy(hd->linkname,arcn->ln_name, sizeof(hd->linkname));
		if (ul_oct((u_long)0L, hd->size, sizeof(hd->size), 1))
			goto out;
	} else {
		/*
		 * data follows this file, so set the pad
		 */
		hd->linkflag = AREGTYPE;
		bzero(hd->linkname, sizeof(hd->linkname));
#		ifdef NET2_STAT
		if (ul_oct((u_long)arcn->sb.st_size, hd->size,
		    sizeof(hd->size), 1)) {
#		else
		if (uqd_oct((u_quad_t)arcn->sb.st_size, hd->size,
		    sizeof(hd->size), 1)) {
#		endif
			warn(1,"File is too large for tar %s", arcn->org_name);
			return(1);
		}
		arcn->pad = TAR_PAD(arcn->sb.st_size);
	}

	/*
	 * copy those fields that are independent of the type
	 */
	if (ul_oct((u_long)arcn->sb.st_mode, hd->mode, sizeof(hd->mode), 0) ||
	    ul_oct((u_long)arcn->sb.st_uid, hd->uid, sizeof(hd->uid), 0) ||
	    ul_oct((u_long)arcn->sb.st_gid, hd->gid, sizeof(hd->gid), 0) ||
	    ul_oct((u_long)arcn->sb.st_mtime, hd->mtime, sizeof(hd->mtime), 1))
		goto out;

	/*
	 * calculate and add the checksum, then write the header. A return of
	 * 0 tells the caller to now write the file data, 1 says no data needs
	 * to be written
	 */
	if (ul_oct(tar_chksm(hdblk, sizeof(HD_TAR)), hd->chksum,
	    sizeof(hd->chksum), 2))
		goto out;
	if (wr_rdbuf(hdblk, sizeof(HD_TAR)) < 0)
		return(-1);
	if (wr_skip((off_t)(BLKMULT - sizeof(HD_TAR))) < 0)
		return(-1);
	if ((arcn->type == PAX_CTG) || (arcn->type == PAX_REG))
		return(0);
	return(1);

    out:
	/*
	 * header field is out of range
	 */
	warn(1, "Tar header field is too small for %s", arcn->org_name);
	return(1);
}

/*
 * Routines for POSIX ustar
 */

/*
 * ustar_strd()
 *	initialization for ustar read
 * Return:
 *	0 if ok, -1 otherwise
 */

#if __STDC__
int
ustar_strd(void)
#else
int
ustar_strd()
#endif
{
	if ((usrtb_start() < 0) || (grptb_start() < 0))
		return(-1);
	return(0);
}

/*
 * ustar_stwr()
 *	initialization for ustar write
 * Return:
 *	0 if ok, -1 otherwise
 */

#if __STDC__
int
ustar_stwr(void)
#else
int
ustar_stwr()
#endif
{
	if ((uidtb_start() < 0) || (gidtb_start() < 0))
		return(-1);
	return(0);
}

/*
 * ustar_id()
 *	determine if a block given to us is a valid ustar header. We have to
 *	be on the lookout for those pesky blocks of all zero's
 * Return:
 *	0 if a ustar header, -1 otherwise
 */

#if __STDC__
int
ustar_id(char *blk, int size)
#else
int
ustar_id(blk, size)
	char *blk;
	int size;
#endif
{
	register HD_USTAR *hd;

	if (size < BLKMULT)
		return(-1);
	hd = (HD_USTAR *)blk;

	/*
	 * check for block of zero's first, a simple and fast test then check
	 * ustar magic cookie. We should use TMAGLEN, but some USTAR archive
	 * programs are fouled up and create archives missing the \0. Last we
	 * check the checksum. If ok we have to assume it is a valid header.
	 */
	if (hd->name[0] == '\0')
		return(-1);
	if (strncmp(hd->magic, TMAGIC, TMAGLEN - 1) != 0)
		return(-1);
	if (asc_ul(hd->chksum,sizeof(hd->chksum),OCT) != tar_chksm(blk,BLKMULT))
		return(-1);
	return(0);
}

/*
 * ustar_rd()
 *	extract the values out of block already determined to be a ustar header.
 *	store the values in the ARCHD parameter.
 * Return:
 *	0
 */

#if __STDC__
int
ustar_rd(register ARCHD *arcn, register char *buf)
#else
int
ustar_rd(arcn, buf)
	register ARCHD *arcn;
	register char *buf;
#endif
{
	register HD_USTAR *hd;
	register char *dest;
	register int cnt = 0;
	dev_t devmajor;
	dev_t devminor;

	/*
	 * we only get proper sized buffers
	 */
	if (ustar_id(buf, BLKMULT) < 0)
		return(-1);
	arcn->org_name = arcn->name;
	arcn->sb.st_nlink = 1;
	arcn->pat = NULL;
	hd = (HD_USTAR *)buf;

	/*
	 * see if the filename is split into two parts. if, so joint the parts.
	 * we copy the prefix first and add a / between the prefix and name.
	 */
	dest = arcn->name;
	if (*(hd->prefix) != '\0') {
		cnt = l_strncpy(arcn->name, hd->prefix, sizeof(hd->prefix));
		dest = arcn->name + arcn->nlen;
		*dest++ = '/';
	}
	arcn->nlen = l_strncpy(dest, hd->name, sizeof(hd->name));
	arcn->nlen += cnt;
	arcn->name[arcn->nlen] = '\0';

	/*
	 * follow the spec to the letter. we should only have mode bits, strip
	 * off all other crud we may be passed.
	 */
	arcn->sb.st_mode = (mode_t)(asc_ul(hd->mode, sizeof(hd->mode), OCT) &
	    0xfff);
	arcn->sb.st_size = (size_t)asc_ul(hd->size, sizeof(hd->size), OCT);
	arcn->sb.st_mtime = (time_t)asc_ul(hd->mtime, sizeof(hd->mtime), OCT);
	arcn->sb.st_ctime = arcn->sb.st_atime = arcn->sb.st_mtime;

	/*
	 * If we can find the ascii names for gname and uname in the password
	 * and group files we will use the uid's and gid they bind. Otherwise
	 * we use the uid and gid values stored in the header. (This is what
	 * the posix spec wants).
	 */
	hd->gname[sizeof(hd->gname) - 1] = '\0';
	if (gid_name(hd->gname, &(arcn->sb.st_gid)) < 0)
		arcn->sb.st_gid = (gid_t)asc_ul(hd->gid, sizeof(hd->gid), OCT);
	hd->uname[sizeof(hd->uname) - 1] = '\0';
	if (uid_name(hd->uname, &(arcn->sb.st_uid)) < 0)
		arcn->sb.st_uid = (uid_t)asc_ul(hd->uid, sizeof(hd->uid), OCT);

	/*
	 * set the defaults, these may be changed depending on the file type
	 */
	arcn->ln_name[0] = '\0';
	arcn->ln_nlen = 0;
	arcn->pad = 0;
	arcn->skip = 0;
	arcn->sb.st_rdev = (dev_t)0;

	/*
	 * set the mode and PAX type according to the typeflag in the header
	 */
	switch(hd->typeflag) {
	case FIFOTYPE:
		arcn->type = PAX_FIF;
		arcn->sb.st_mode |= S_IFIFO;
		break;
	case DIRTYPE:
		arcn->type = PAX_DIR;
		arcn->sb.st_mode |= S_IFDIR;
		arcn->sb.st_nlink = 2;

		/*
		 * Some programs that create ustar archives append a '/'
		 * to the pathname for directories. This clearly violates
		 * ustar specs, but we will silently strip it off anyway.
		 */
		if (arcn->name[arcn->nlen - 1] == '/')
			arcn->name[--arcn->nlen] = '\0';
		break;
	case BLKTYPE:
	case CHRTYPE:
		/*
		 * this type requires the rdev field to be set.
		 */
		if (hd->typeflag == BLKTYPE) {
			arcn->type = PAX_BLK;
			arcn->sb.st_mode |= S_IFBLK;
		} else {
			arcn->type = PAX_CHR;
			arcn->sb.st_mode |= S_IFCHR;
		}
		devmajor = (dev_t)asc_ul(hd->devmajor,sizeof(hd->devmajor),OCT);
		devminor = (dev_t)asc_ul(hd->devminor,sizeof(hd->devminor),OCT);
		arcn->sb.st_rdev = TODEV(devmajor, devminor);
		break;
	case SYMTYPE:
	case LNKTYPE:
		if (hd->typeflag == SYMTYPE) {
			arcn->type = PAX_SLK;
			arcn->sb.st_mode |= S_IFLNK;
		} else {
			arcn->type = PAX_HLK;
			/*
			 * so printing looks better
			 */
			arcn->sb.st_mode |= S_IFREG;
			arcn->sb.st_nlink = 2;
		}
		/*
		 * copy the link name
		 */
		arcn->ln_nlen = l_strncpy(arcn->ln_name, hd->linkname,
			sizeof(hd->linkname));
		arcn->ln_name[arcn->ln_nlen] = '\0';
		break;
	case CONTTYPE:
	case AREGTYPE:
	case REGTYPE:
	default:
		/*
		 * these types have file data that follows. Set the skip and
		 * pad fields.
		 */
		arcn->type = PAX_REG;
		arcn->pad = TAR_PAD(arcn->sb.st_size);
		arcn->skip = arcn->sb.st_size;
		arcn->sb.st_mode |= S_IFREG;
		break;
	}
	return(0);
}

/*
 * ustar_wr()
 *	write a ustar header for the file specified in the ARCHD to the archive
 *	Have to check for file types that cannot be stored and file names that
 *	are too long. Be careful of the term (last arg) to ul_oct, we only use
 *	'\0' for the termination character (this is different than picky tar)
 *	ASSUMED: space after header in header block is zero filled
 * Return:
 *	0 if file has data to be written after the header, 1 if file has NO
 *	data to write after the header, -1 if archive write failed
 */

#if __STDC__
int
ustar_wr(register ARCHD *arcn)
#else
int
ustar_wr(arcn)
	register ARCHD *arcn;
#endif
{
	register HD_USTAR *hd;
	register char *pt;
	char hdblk[sizeof(HD_USTAR)];

	/*
	 * check for those file system types ustar cannot store
	 */
	if (arcn->type == PAX_SCK) {
		warn(1, "Ustar cannot archive a socket %s", arcn->org_name);
		return(1);
	}

	/*
	 * check the length of the linkname
	 */
	if (((arcn->type == PAX_SLK) || (arcn->type == PAX_HLK) ||
	    (arcn->type == PAX_HRG)) && (arcn->ln_nlen > sizeof(hd->linkname))){
		warn(1, "Link name too long for ustar %s", arcn->ln_name);
		return(1);
	}

	/*
	 * split the path name into prefix and name fields (if needed). if
	 * pt != arcn->name, the name has to be split
	 */
	if ((pt = name_split(arcn->name, arcn->nlen)) == NULL) {
		warn(1, "File name too long for ustar %s", arcn->name);
		return(1);
	}
	hd = (HD_USTAR *)hdblk;
	arcn->pad = 0L;

	/*
	 * split the name, or zero out the prefix
	 */
	if (pt != arcn->name) {
		/*
		 * name was split, pt points at the / where the split is to
		 * occur, we remove the / and copy the first part to the prefix
		 */
		*pt = '\0';
		zf_strncpy(hd->prefix, arcn->name, sizeof(hd->prefix));
		*pt++ = '/';
	} else
		bzero(hd->prefix, sizeof(hd->prefix));

	/*
	 * copy the name part. this may be the whole path or the part after
	 * the prefix
	 */
	zf_strncpy(hd->name, pt, sizeof(hd->name));

	/* 
	 * set the fields in the header that are type dependent
	 */
	switch(arcn->type) {
	case PAX_DIR:
		hd->typeflag = DIRTYPE;
		bzero(hd->linkname, sizeof(hd->linkname));
		bzero(hd->devmajor, sizeof(hd->devmajor));
		bzero(hd->devminor, sizeof(hd->devminor));
		if (ul_oct((u_long)0L, hd->size, sizeof(hd->size), 3))
			goto out;
		break;
	case PAX_CHR:
	case PAX_BLK:
		if (arcn->type == PAX_CHR)
			hd->typeflag = CHRTYPE;
		else
			hd->typeflag = BLKTYPE;
		bzero(hd->linkname, sizeof(hd->linkname));
		if (ul_oct((u_long)MAJOR(arcn->sb.st_rdev), hd->devmajor,
		   sizeof(hd->devmajor), 3) ||
		   ul_oct((u_long)MINOR(arcn->sb.st_rdev), hd->devminor,
		   sizeof(hd->devminor), 3) ||
		   ul_oct((u_long)0L, hd->size, sizeof(hd->size), 3))
			goto out;
		break;
	case PAX_FIF:
		hd->typeflag = FIFOTYPE;
		bzero(hd->linkname, sizeof(hd->linkname));
		bzero(hd->devmajor, sizeof(hd->devmajor));
		bzero(hd->devminor, sizeof(hd->devminor));
		if (ul_oct((u_long)0L, hd->size, sizeof(hd->size), 3))
			goto out;
		break;
	case PAX_SLK:
	case PAX_HLK:
	case PAX_HRG:
		if (arcn->type == PAX_SLK)
			hd->typeflag = SYMTYPE;
		else
			hd->typeflag = LNKTYPE;
		zf_strncpy(hd->linkname,arcn->ln_name, sizeof(hd->linkname));
		bzero(hd->devmajor, sizeof(hd->devmajor));
		bzero(hd->devminor, sizeof(hd->devminor));
		if (ul_oct((u_long)0L, hd->size, sizeof(hd->size), 3))
			goto out;
		break;
	case PAX_REG:
	case PAX_CTG:
	default:
		/*
		 * file data with this type, set the padding
		 */
		if (arcn->type == PAX_CTG)
			hd->typeflag = CONTTYPE;
		else
			hd->typeflag = REGTYPE;
		bzero(hd->linkname, sizeof(hd->linkname));
		bzero(hd->devmajor, sizeof(hd->devmajor));
		bzero(hd->devminor, sizeof(hd->devminor));
		arcn->pad = TAR_PAD(arcn->sb.st_size);
#		ifdef NET2_STAT
		if (ul_oct((u_long)arcn->sb.st_size, hd->size,
		    sizeof(hd->size), 3)) {
#		else
		if (uqd_oct((u_quad_t)arcn->sb.st_size, hd->size,
		    sizeof(hd->size), 3)) {
#		endif
			warn(1,"File is too long for ustar %s",arcn->org_name);
			return(1);
		}
		break;
	}

	zf_strncpy(hd->magic, TMAGIC, TMAGLEN);
	zf_strncpy(hd->version, TVERSION, TVERSLEN);

	/*
	 * set the remaining fields. Some versions want all 16 bits of mode
	 * we better humor them (they really do not meet spec though)....
	 */
	if (ul_oct((u_long)arcn->sb.st_mode, hd->mode, sizeof(hd->mode), 3) ||
	    ul_oct((u_long)arcn->sb.st_uid, hd->uid, sizeof(hd->uid), 3)  ||
	    ul_oct((u_long)arcn->sb.st_gid, hd->gid, sizeof(hd->gid), 3) ||
	    ul_oct((u_long)arcn->sb.st_mtime,hd->mtime,sizeof(hd->mtime),3))
		goto out;
	zf_strncpy(hd->uname,name_uid(arcn->sb.st_uid, 0),sizeof(hd->uname));
	zf_strncpy(hd->gname,name_gid(arcn->sb.st_gid, 0),sizeof(hd->gname));

	/*
	 * calculate and store the checksum write the header to the archive
	 * return 0 tells the caller to now write the file data, 1 says no data
	 * needs to be written
	 */
	if (ul_oct(tar_chksm(hdblk, sizeof(HD_USTAR)), hd->chksum,
	   sizeof(hd->chksum), 3))
		goto out;
	if (wr_rdbuf(hdblk, sizeof(HD_USTAR)) < 0)
		return(-1);
	if (wr_skip((off_t)(BLKMULT - sizeof(HD_USTAR))) < 0)
		return(-1);
	if ((arcn->type == PAX_CTG) || (arcn->type == PAX_REG))
		return(0);
	return(1);

    out:
    	/*
	 * header field is out of range
	 */
	warn(1, "Ustar header field is too small for %s", arcn->org_name);
	return(1);
}

/*
 * name_split()
 *	see if the name has to be split for storage in a ustar header. We try
 *	to fit the entire name in the name field without splitting if we can.
 *	The split point is always at a /
 * Return
 *	character pointer to split point (always the / that is to be removed
 *	if the split is not needed, the points is set to the start of the file
 *	name (it would violate the spec to split there). A NULL is returned if
 *	the file name is too long
 */

#if __STDC__
static char *
name_split(register char *name, register int len)
#else
static char *
name_split(name, len)
	register char *name;
	register int len;
#endif
{
	register char *start;

	/*
	 * check to see if the file name is small enough to fit in the name
	 * field. if so just return a pointer to the name.
	 */
	if (len <= TNMSZ)
		return(name);
	if (len > (TPFSZ + TNMSZ + 1))
		return(NULL);

	/*
	 * we start looking at the biggest sized piece that fits in the name
	 * field. We walk foward looking for a slash to split at. The idea is
	 * to find the biggest piece to fit in the name field (or the smallest
	 * prefix we can find) (the -1 is correct the biggest piece would
	 * include the slash between the two parts that gets thrown away)
	 */
	start = name + len - TNMSZ - 1;
	while ((*start != '\0') && (*start != '/'))
		++start;

	/*
	 * if we hit the end of the string, this name cannot be split, so we
	 * cannot store this file.
	 */
	if (*start == '\0')
		return(NULL);
	len = start - name;

	/*
	 * NOTE: /str where the length of str == TNMSZ can not be stored under
	 * the p1003.1-1990 spec for ustar. We could force a prefix of / and
	 * the file would then expand on extract to //str. The len == 0 below
	 * makes this special case follow the spec to the letter.
	 */
	if ((len > TPFSZ) || (len == 0))
		return(NULL);

	/*
	 * ok have a split point, return it to the caller
	 */
	return(start);
}