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I am working on an embedded Linux system (kernel-5.10.24), and it uses ash from busybox as /bin/sh. The system support login from serial console and adb shell from PC.

Now I found the shell started from serial console did read the environments defined in /etc/profile, but the shell started by adb shell does NOT.

For example, the /etc/profile is as follows,

# cat /etc/profile export PATH="/bin:/sbin:/usr/bin:/usr/sbin" if [ "$PS1" ]; then if [ "`id -u`" -eq 0 ]; then export PS1='# ' else export PS1='$ ' fi fi

in serial console,

# echo $HOME /root # echo $ENV # echo $PATH /bin:/sbin:/usr/bin:/usr/sbin

But in adb shell,

/sys/kernel/config/usb_gadget # echo $PATH /sbin:/usr/sbin:/bin:/usr/bin /sys/kernel/config/usb_gadget # echo $HOME /

The shell started by adb shell is launched by adbd in target Linux, so is there a way to make the shell started by adb shell to read /etc/profile or other configuration files for its environments?

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3 Answers 3

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You could try use a wrapper script for achieve what you are asking for:

adb shell 'ENV=/etc/profile sh -i'

A simple alias for this could be:

alias adbshellenv="adb shell 'ENV=/etc/profile sh -i'"
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  • So where should I put the wrapper script, in Linux where the adbd is running? Commented Oct 30, 2023 at 0:55
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With lots of studies and tests, I think I found one way to solve my request/answer.

Firstly, change the source codes of adbd to call a wrapper script of /etc/init.d/adbshell_wrapper.sh in target Linux.
The wrapper script calls at least 2 things, as follows,

#!/bin/sh /etc/profile /bin/sh

With this solution, the adb shell can get the same environments as what login gets in serial console.

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From the beginning of the INVOCATION chapter of man bash:

A login shell is one whose first character of argument zero is a -, or one started with the --login option.

So just change adbd to set the argv[0] of the shell it's starting to e.g. -bash.

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  • If the system is using ash not bash, shall I use -ash? If so, I will try that and update my result here. Commented Mar 2, 2024 at 12:32
  • Yes. Although you could technically set it to any value that includes - as the first character, using the name of the shell that's being invoked is the expected behavior. Commented Mar 3, 2024 at 1:41
  • I am not sure if I really got your point. I changed the source code of adbd to launch shell as /bin/sh -ash, is it correct or not? I got following result, PS C:\Users\test> adb shell - exec '/bin/sh --login' failed: No such file or directory (2) - Commented Mar 5, 2024 at 6:19

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