[PATCH] busybox binary name

[Tito]

On Saturday 05 March 2011 16:51:11 Tito wrote:
> On Wednesday 02 March 2011 02:19:02 Denys Vlasenko wrote:
> > On Tuesday 01 March 2011 22:08, Tobias Poschwatta wrote:
> > > The attached patch allows to change the name of the main busybox binary
> > > to something other than "busybox". This makes it easy to have two or
> > > more busybox binaries (different versions, different feature sets, etc.)
> > > installed in the same filesystem.
> > 
> > It is already possible by using a suffix:
> > 
> > # cp busybox busybox2
> > # ./busybox2
> > BusyBox v1.19.0.git (2011-03-01 16:23:40 CET) multi-call binary.
> > Copyright (C) 1998-2009 Erik Andersen, Rob Landley, Denys Vlasenko
> > and others. Licensed under GPLv2.
> > See source distribution for full notice.
> > 
> > Usage: busybox [function] [arguments]...
> >    or: busybox --list[-full]
> >    or: function [arguments]...
> > 
> >         BusyBox is a multi-call binary that combines many common Unix
> >         utilities into a single executable.  Most people will create a
> >         link to busybox for each function they wish to use and BusyBox
> >         will act like whatever it was invoked as.
> > 
> > Currently defined functions:
> >         [, [[, acpid, add-shell, addgroup, adduser ...
> > 
> 
> Hi,
> while inspecting the behaviour of busybox --install -s in a chroot
> environment I've noticed something that looks wrong to me:
> 
> 
> lrwxrwxrwx 1 0 0     14 Mar  5 14:02 addgroup -> /proc/self/exe
> lrwxrwxrwx 1 0 0     14 Mar  5 14:02 adduser -> /proc/self/exe
> lrwxrwxrwx 1 0 0     14 Mar  5 14:02 ash -> /proc/self/exe
> lrwxrwxrwx 1 0 0     14 Mar  5 14:02 base64 -> /proc/self/exe
> -rwxr-xr-x 1 0 0 700492 Mar  5 13:55 bash
> -rwxr-xr-x 1 0 0 724192 Mar  5 13:56 busybox
> lrwxrwxrwx 1 0 0     14 Mar  5 14:02 cat -> /proc/self/exe
> lrwxrwxrwx 1 0 0     14 Mar  5 14:02 catv -> /proc/self/exe
> lrwxrwxrwx 1 0 0     14 Mar  5 14:02 chattr -> /proc/self/exe
> lrwxrwxrwx 1 0 0     14 Mar  5 14:02 chgrp -> /proc/self/exe
> lrwxrwxrwx 1 0 0     14 Mar  5 14:02 chmod -> /proc/self/exe
> lrwxrwxrwx 1 0 0     14 Mar  5 14:02 chown -> /proc/self/exe
> lrwxrwxrwx 1 0 0     14 Mar  5 14:02 cp -> /proc/self/exe
> lrwxrwxrwx 1 0 0     14 Mar  5 14:02 cpio -> /proc/self/exe
> lrwxrwxrwx 1 0 0     14 Mar  5 14:02 cttyhack -> /proc/self/exe
> lrwxrwxrwx 1 0 0     14 Mar  5 14:02 date -> /proc/self/exe
> 
> 
> all links point to /proc/self/exe as bb_busybox_exec_path is used :
> 
> config BUSYBOX_EXEC_PATH
> 	string "Path to BusyBox executable"
> 	default "/proc/self/exe"
> 	help
> 	  When Busybox applets need to run other busybox applets, BusyBox
> 	  sometimes needs to exec() itself. When the /proc filesystem is
> 	  mounted, /proc/self/exe always points to the currently running
> 	  executable. If you haven't got /proc, set this to wherever you
> 	  want to run BusyBox from.
> 
> This seems not to be a sane default here as
> 1) was not able to make this work in a chrooted env
> 2) in case of failure  xmalloc_readlink symlinks
>     point to /proc/self/exe
> 3) it works only if /proc/ is mounted
> 
> I would suggest rather than doing it automagically
> as this setp is done only at setup time (from a known path i suppose)
> to enforce that the busybox binary is called on the command line
> with the full path, the pros are:
> 
> 1) no need for /proc
> 2) name of busybox could be changed and different busybox
>     executables could be used at the same time.
> 3) works in my chroot env.
> 4) it is simple.
> 
> 	if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) {
> 		int use_symbolic_links = (argv[2] && strcmp(argv[2], "-s") == 0);	
> 		if (!strchr(argv[0], '/'))
> 			bb_error_msg_and_die("Please call %s with the full path", argv[0]);
> 		/* busybox --install [-s] [DIR]: */
> 		/* -s: make symlinks */
> 		/* DIR: directory to install links to */
> 		install_links(argv[0], use_symbolic_links, (argv[3]) ? argv[3] : NULL);
> 		return 0;
> 	}
> 
> Hints, critics, improvements are welcome.
> Ciao,
> Tito
> 
> 

Minor fix to catch ./busybox.
Attached patch v2.

	if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) {
		int use_symbolic_links = (argv[2] && strcmp(argv[2], "-s") == 0);
		if (strncmp(argv[0], "./", 2) == 0 || !strchr(argv[0], '/'))
			bb_error_msg_and_die("Please call %s with the full path", argv[0]);
		/* busybox --install [-s] [DIR]: */
		/* -s: make symlinks */
		/* DIR: directory to install links to */
		install_links(argv[0], use_symbolic_links, (argv[3]) ? argv[3] : NULL);
		return 0;
	}

Ciao,
Tito


-------------- next part --------------
A non-text attachment was scrubbed...
Name: install_v2.patch
Type: text/x-diff
Size: 998 bytes
Desc: not available
URL: <http://lists.busybox.net/pipermail/busybox/attachments/20110305/67d39b11/attachment.bin>