[File] [PATCH] of Magdir/linux for Linux kernel (extensions; URL)

[Christos Zoulas]

On Mar 10,  1:18am, joerg.jen.der.ek at gmx.net (=?UTF-8?Q?J=c3=b6rg_Jenderek?=) wrote:
-- Subject: [File] [PATCH] of Magdir/linux for Linux kernel (extensions; URL)

| Hello,
| some days ago i run file command version 5.36 on some Linux kernels with
| options --extension and --keep-going. For most examples no extension is
| found ("???" displayed) or wrong extension "com" by Magdir/msdos is show
| n.
| The examples are identified by Magdir/linux correctly as "Linux
| kernel" like
| damnsmll.lnx:    Linux kernel x86 boot executable bzImage,
| 	version 2.4.26 (root at Knoppix)
| 	#1 SMP Sa Apr 17 19:33:42 CEST 2004,
| 	RO-rootFS, root_dev 0x301, Normal VGA
| kernel64.dat:    Linux kernel x86 boot executable bzImage,
| 	version 3.11.6-acronis-b313-x86_64 (rnd at acronis)
| 	#1 SMP Mon Feb 10 05:13:59 PST 2014,
| 	RO-rootFS, swap_dev 0x2, Normal VGA
| kernel7.img:     Linux kernel ARM boot executable zImage (little-endian)
| kernel_auto.bin: Linux kernel ARM boot executable zImage (little-endian)
| memdisk:         Linux kernel x86 boot executable bzImage,
| 	version MEMDISK 3.71 Debian-2008-09-06,
| 	RW-rootFS,
| memdisk16.bin:   Linux kernel x86 boot executable bzImage,
| 	version MEMDISK 4.05 0x4ee25341,
| 	RW-rootFS,
| plpbtrom.bin:    Linux kernel x86 boot executable zImage,
| 	RW-rootFS,
| So i add lines to that magic file.
| Normally Linux kernel have names without extension like bzimage, vmlinuz
| or memdisk. But some manufactures use other names like kernel64.dat for
| Acronis Recovery medium, plpbtrom.bin for the Plop Boot Manager or
| damnsmll.lnx for DamnSmallLinux 1.5.
| This is now expressed by additional line
|  !:ext	/dat/bin/lnx
| The above applies mainly to x86 boot executable. For x86 kernel more
| information fields like version, video mode, etc. is displayed. These
| fields of such kernel headers are explained in "THE LINUX/x86 BOOT
| PROTOCOL" in the linux kernel documentation. This is now expressed by
| additional remark line
|  # URL: https://www.kernel.org/doc/Documentation/x86/boot.txt
| 
| There are other patterns for kernels on other architectures. So
| for Linux kernel ARM boot executable zImage (little-endian) i found
| "kernel7.img" on raspian distribution and "kernel_auto.bin" on tv
| receiver with brand Vu+. This is now expressed by additional line
|  !:ext	img/bin
| 
| After applying the above mentioned modifications by patch
| file-5.36-linux-kernel-extension.diff then all inspected examples are
| described with --extension option like
| damnsmll.lnx:    /dat/bin/lnx
| kernel64.dat:    /dat/bin/lnx
| kernel7.img:     img/bin
| kernel_auto.bin: img/bin
| memdisk:         /dat/bin/lnx
| memdisk16.bin:   /dat/bin/lnx
| plpbtrom.bin:    /dat/bin/lnx
| I hope my diff file can be applied in future version of file utility.
| 
| Furthermore i saw that the Linux kernel field information is shown in a
| non logical way. For one branch information is shown by lines like
|  >>498	leshort		1		RO-rootFS,
|  >>498	leshort		0		RW-rootFS,
|  >>508	leshort		>0		root_dev 0x%X,
|  >>502	leshort		>0		swap_dev 0x%X,
| For another Linux kernel branch the same field information is shown but
| using other phrases and line order like
|  >>502	leshort		>0		swap=0x%X
|  >>508	leshort		>0		root=0x%X
|  >>>498	leshort		1		\b-ro
|  >>>498	leshort		0		\b-rw
| Furthermore so such magic lines information is redundant.
| 
| Or with --keep-going option i get 3 message for the same kernel by 3
| magic lines
|  0	string		\xb8\xc0\x07\x8e\xd8\xb8\x00\x90 Linux
|  0	belong		0xb8c0078e			 Linux
|  0	belong		0xb8c0078e			 Linux kernel
| So a cleanup and unification makes sense to me. Unfortunately my
| knowledge about Linux kernel and non x86 architectures is limited to do
| that.
| 
| With best wishes
| Jörg Jenderek
| - -- 
| Jörg Jenderek
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Committed thanks!

christos