Adding upstream version 1:5.44.upstream/1%5.44upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 179 insertions, 0 deletions

diff --git a/src/is_tar.c b/src/is_tar.c
new file mode 100644
index 0000000..fa83e1e
--- /dev/null
+++ b/src/is_tar.c
@@ -0,0 +1,179 @@
+/*
+ * Copyright (c) Ian F. Darwin 1986-1995.
+ * Software written by Ian F. Darwin and others;
+ * maintained 1995-present by Christos Zoulas and others.
+ *
+ * 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 immediately at the beginning of the file, without modification,
+ *    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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+ */
+/*
+ * is_tar() -- figure out whether file is a tar archive.
+ *
+ * Stolen (by the author!) from the file_public domain tar program:
+ * Public Domain version written 26 Aug 1985 John Gilmore (ihnp4!hoptoad!gnu).
+ *
+ * @(#)list.c 1.18 9/23/86 Public Domain - gnu
+ *
+ * Comments changed and some code/comments reformatted
+ * for file command by Ian Darwin.
+ */
+
+#include "file.h"
+
+#ifndef lint
+FILE_RCSID("@(#)$File: is_tar.c,v 1.50 2022/12/26 17:31:14 christos Exp $")
+#endif
+
+#include "magic.h"
+#include <string.h>
+#include <ctype.h>
+#include "tar.h"
+
+#define	isodigit(c)	( ((c) >= '0') && ((c) <= '7') )
+
+file_private int is_tar(const unsigned char *, size_t);
+file_private int from_oct(const char *, size_t);	/* Decode octal number */
+
+static const char tartype[][32] = {	/* should be equal to messages */
+	"tar archive",			/* found in ../magic/Magdir/archive */
+	"POSIX tar archive",
+	"POSIX tar archive (GNU)",	/*  */
+};
+
+file_protected int
+file_is_tar(struct magic_set *ms, const struct buffer *b)
+{
+	const unsigned char *buf = CAST(const unsigned char *, b->fbuf);
+	size_t nbytes = b->flen;
+	/*
+	 * Do the tar test first, because if the first file in the tar
+	 * archive starts with a dot, we can confuse it with an nroff file.
+	 */
+	int tar;
+	int mime = ms->flags & MAGIC_MIME;
+
+	if ((ms->flags & (MAGIC_APPLE|MAGIC_EXTENSION)) != 0)
+		return 0;
+
+	tar = is_tar(buf, nbytes);
+	if (tar < 1 || tar > 3)
+		return 0;
+
+	if (mime == MAGIC_MIME_ENCODING)
+		return 1;
+
+	if (file_printf(ms, "%s", mime ? "application/x-tar" :
+	    tartype[tar - 1]) == -1)
+		return -1;
+
+	return 1;
+}
+
+/*
+ * Return
+ *	0 if the checksum is bad (i.e., probably not a tar archive),
+ *	1 for old UNIX tar file,
+ *	2 for Unix Std (POSIX) tar file,
+ *	3 for GNU tar file.
+ */
+file_private int
+is_tar(const unsigned char *buf, size_t nbytes)
+{
+	static const char gpkg_match[] = "/gpkg-1";
+
+	const union record *header = RCAST(const union record *,
+	    RCAST(const void *, buf));
+	size_t i;
+	int sum, recsum;
+	const unsigned char *p, *ep;
+	const char *nulp;
+
+	if (nbytes < sizeof(*header))
+		return 0;
+
+	/* If the file looks like Gentoo GLEP 78 binary package (GPKG),
+	 * don't waste time on further checks and fall back to magic rules.
+	 */
+	nulp = CAST(const char *,
+	    memchr(header->header.name, 0, sizeof(header->header.name)));
+	if (nulp != NULL && nulp >= header->header.name + sizeof(gpkg_match) &&
+	    memcmp(nulp - sizeof(gpkg_match) + 1, gpkg_match,
+	    sizeof(gpkg_match)) == 0)
+	    return 0;
+
+	recsum = from_oct(header->header.chksum, sizeof(header->header.chksum));
+
+	sum = 0;
+	p = header->charptr;
+	ep = header->charptr + sizeof(*header);
+	while (p < ep)
+		sum += *p++;
+
+	/* Adjust checksum to count the "chksum" field as blanks. */
+	for (i = 0; i < sizeof(header->header.chksum); i++)
+		sum -= header->header.chksum[i];
+	sum += ' ' * sizeof(header->header.chksum);
+
+	if (sum != recsum)
+		return 0;	/* Not a tar archive */
+
+	if (strncmp(header->header.magic, GNUTMAGIC,
+	    sizeof(header->header.magic)) == 0)
+		return 3;		/* GNU Unix Standard tar archive */
+
+	if (strncmp(header->header.magic, TMAGIC,
+	    sizeof(header->header.magic)) == 0)
+		return 2;		/* Unix Standard tar archive */
+
+	return 1;			/* Old fashioned tar archive */
+}
+
+
+/*
+ * Quick and dirty octal conversion.
+ *
+ * Result is -1 if the field is invalid (all blank, or non-octal).
+ */
+file_private int
+from_oct(const char *where, size_t digs)
+{
+	int	value;
+
+	if (digs == 0)
+		return -1;
+
+	while (isspace(CAST(unsigned char, *where))) {	/* Skip spaces */
+		where++;
+		if (digs-- == 0)
+			return -1;		/* All blank field */
+	}
+	value = 0;
+	while (digs > 0 && isodigit(*where)) {	/* Scan til non-octal */
+		value = (value << 3) | (*where++ - '0');
+		digs--;
+	}
+
+	if (digs > 0 && *where && !isspace(CAST(unsigned char, *where)))
+		return -1;			/* Ended on non-(space/NUL) */
+
+	return value;
+}