Subject: Re: [PATCH] tar: on extract, -o is --no-same-owner

From: Denys Vlasenko <[email-masked]>
Date: Sun, 25 Oct 2009 01:32:04 +0200

On Saturday 24 October 2009 12:44, Andreas Schwab wrote:
> Bernhard Reutner-Fischer <[email-masked]> writes:
> 
> > On Sat, Oct 24, 2009 at 11:49:10AM +0200, Andreas Schwab wrote:
> >>Bernhard Reutner-Fischer <[email-masked]> writes:
> >>
> >>> I suppose xf - -o would work?
> >>
> >>Isn't that the same as 'xfo -'?
> >
> > Not really (if you do not permute the arguments which we don't in
> > busybox, for size reasons).
> 
> There is no argument permutation.  The traditional argument parsing of
> tar does not cluster option letters with option arguments.
> 
> Of course, just using 'xof -' will work around this busybox bug.

From my side, I prefer to squash that busybox bug.
This is the second time people complain about it,
so it is a reoccurring problem.

The attached patch has been pushed to busybox git.

function                                             old     new   delta
tar_main                                             702     751     +49

--
vda
diff -d -urpN busybox.0/archival/tar.c busybox.1/archival/tar.c
--- busybox.0/archival/tar.c	2009-10-20 22:11:09.000000000 +0200
+++ busybox.1/archival/tar.c	2009-10-25 01:27:38.000000000 +0200
@@ -841,6 +841,33 @@ int tar_main(int argc UNUSED_PARAM, char
 #if ENABLE_FEATURE_TAR_LONG_OPTIONS
 	applet_long_options = tar_longopts;
 #endif
+#if ENABLE_DESKTOP
+	if (argv[1][0] != '-') {
+		/* Compat:
+		 * 1st argument without dash handles options with parameters
+		 * differently from dashed one: it takes *next argv[i]*
+		 * as paramenter even if there are more chars in 1st argument:
+		 *  "tar fx TARFILE" - "x" is not taken as f's param
+		 *  but is interpreted as -x option
+		 *  "tar -xf TARFILE" - dashed equivalent of the above
+		 *  "tar -fx ..." - "x" is taken as f's param
+		 * getopt32 wouldn't handle 1st command correctly.
+		 * Unfortunately, people do use such commands.
+		 * We massage argv[1] to work around it by moving 'f'
+		 * to the end of the string.
+		 * More contrived "tar fCx TARFILE DIR" still fails,
+		 * but such commands are much less likely to be used.
+		 */
+		char *f = strchr(argv[1], 'f');
+		if (f) {
+			while (f[1] != '\0') {
+				*f = f[1];
+				f++;
+			}
+			*f = 'f';
+		}
+	}
+#endif
 	opt = getopt32(argv,
 		"txC:f:Opvk"
 		IF_FEATURE_TAR_CREATE(   "ch"  )