bootchart_init=... does not nothing i.e. use /sbin/init instead of given init command

[solsticedhiver]

I was trying to run /sbin/e4rat-preload as init just after bootchartd
So I used the kernel command line option bootchart_init=/sbin/e4rat-preload along side the other init=/sbin/bootchartd (...)

But it seems the usual /sbin/init was running. I was no mention of e4rat-preload in /var/log/bootchart.png

Looking at /sbin/bootchartd line 176, bootchartd assume that the kernel command line option are passed as arguments to the init process. Well, I don't know if it's the case but not here.
So I fixed it with using
for i in $(cat /proc/cmdline); do

It worked and used e4rat-preload as 2nd init process. I don't know if it has any side effect regarding other option or behavior

[xrmx]

That's strange, which bootchart2 / kernel version are you using?

Could you please add these lines before the loop:

echo cat /proc/cmdline >> $TMPFS/kmsg
echo "params: $@" >> $TMPFS/kmsg
echo env >> $TMPFS/kmsg

and then check dmesg | tail for messages.

Related to this, Issue #27 suggests to completely remove the loop and it makes sense since it matches bootparam(7) :|

[solsticedhiver]

I am using bootchart2 0.14.1, kernel 3.3.4 on archlinux 32 bits which uses an initrd

so in dmesg, I see

1. the output of /proc/cmdline has expected: root=/dev/disk/by-uuid/46xxxxxx-52e9-4d73-accd-2775bcxxxxxx ro quiet acpi_os_name="Microsoft Windows NT" bootchart_init=/usr/sbin/e4rat-preload-lite init=/sbin/bootchartd initcall_debug printk.time=y
2. params gives an empty string ! (which was already reported by xrmx)
3. output of env is: TERM=linux PWD=/ SHLVL=1 _=/usr/bin/env

which explains the bug I am reporting. then why it is that way,I don't know
man bootparam is dated 2007-12-16 here, so may be it's outdated.

I can't find doc about the parameters passed to init

[xrmx]

There weren't changes in bootchartd from 0.14.1 to 0.14.2 so no need to test another version.

The relevant bootparam documentation is this paragraph under "The Argument List" chapter:
Anything of the form 'foo=bar' that is not accepted as a setup function
as described above is then interpreted as an environment variable to be
set. A (useless?) example would be to use 'TERM=vt100' as a boot argu‐
ment.

What does cat /proc/1/cmdline say?

[solsticedhiver]

the output of echo cat /proc/1/cmdline is
/bin/bash/sbin/bootchartd
no space between the 2 ?

[xrmx]

The missing space is not a problem, will try to reproduce here

[maleadt]

This is still broken... I looked into it, and the current bootchart code tries to find bootchart_init in its $@ argument array. AFAIS this cannot work, Linux' init/main.c parses the cmdline and sets environment variables for unrecognised arguments which look like key=val (such as bootchart_init).

However, I tried modifying the code in order to check for $ENV{BOOTCHART_INIT}, but I couldn't get it to work: despite trying to pass various key=val-style arguments, $ENV never contained any of them (tested by invoking /usr/bin/env at the top of /sbin/bootchartd). So although the docs and code make me think using the environment is the correct way, I didn't get it working.

What did work is passing the real init as a normal argument (init=/sbin/bootchartd /sbin/my_custom_init), after which is was available in $@; but this isn't acceptable of course.

[xrmx]

@maleadt Isn't that what 130d775 is supposed to do?
The kernel matches bootparam(7) manual, see http://lxr.linux.no/#linux+v3.9.4/init/main.c#L232 so AFAIU it's not bootchart2 at fault here. Which kernel do you have?

[maleadt]

Hmm, most strange. I'm using Arch Linux, currently at 3.9.4. Booting the following init wrapper:

#!/usr/bin/bash
/usr/bin/env
/usr/bin/echo "Arguments: $*"
/usr/bin/sleep 5
exec /usr/bin/init $*

... with additional kernel arguments init=/usr/bin/init_wrapper bootchart_init=/usr/bin/init ro, I only get to see:

TERM=linux
RD_TIMESTAMP=
PWD=/
SHLVL=1
_=/usr/bin/env
Arguments: