Tiny Core Linux

Tiny Core Base => TCB Talk => Topic started by: GNUser on February 29, 2024, 08:44:17 PM

Title: vestigial /linuxrc
Post by: GNUser on February 29, 2024, 08:44:17 PM

Hello, curaga and Juanito. I'm on TCL15 x86_64, exploring the contents of corepure64.gz for my own education.

I noticed that /linuxrc is a no-op link to busybox:

Code: [Select]

# /linuxrc
linuxrc: applet not found

It turns out TCL's busybox is compiled without the linuxrc applet:

Code: [Select]

# CONFIG_LINUXRC is not set


Code: [Select]

$ busybox --list | grep linux
linux32
linux64
$ busybox.suid --list | grep linux


It seems /linuxrc is a relic from TCL's past. I can confirm that removing it from base system has no ill effects.

Title: Re: vestigial /linuxrc
Post by: Rich on March 01, 2024, 12:25:14 AM

Hi GNUser
linuxrc  also shows up in the kernel sources and vmlinuz.

TC10 32 bit:

Code: [Select]

tc@E310:~$ od -A d -t x1 /mnt/sda1/boot/vmlinuz | grep '1f 8b 08 00'
#        0  1  2  3  4
0014592 00 00 ff e0 1f 8b 08 00 00 00 00 00 02 03 ec 7a
# 14592 + 4 = 14596
tc@E310:~$ dd if=/mnt/sda1/boot/vmlinuz bs=1 skip=14596 | zcat | busybox grep linuxrc
/linuxrc

gzip: stdin: decompression OK, trailing garbage ignored
tc@E310:~$
TC14 64 bit:

Code: [Select]

tc@box:~$ od -A d -t x1 /mnt/sda6/boot/vmlinuz64 | grep '1f 8b 08 00'
#        0  1  2  3  4  5  6  7  8  9 10 11 12
0017088 22 c2 eb 03 f4 eb fd 5a 59 5b 58 c3 1f 8b 08 00
# 17088 + 12 = 17100
tc@box:~$ dd if=/mnt/sda6/boot/vmlinuz64 bs=1 skip=17100 | zcat | busybox grep -o linuxrc
linuxrc
tc@box:~$
Code for searching vmlinuz was found here:
https://stackoverflow.com/a/69801246

Title: Re: vestigial /linuxrc
Post by: curaga on March 01, 2024, 02:51:09 AM

Yeah a remnant symlink, good find.