Shell .profile or /etc/profile for old android 2.3.3

Question

Just rooted my old phone with Android 2.3.3 and I would like to define some aliases for each shell I start (with adb or terminal app). I found this question where one answer says that /etc/profile (=/system/etc/profile due to soft link /etc->/system/etc) is one of the files the shell sources on startup. But this post talks about /system/bin/sh being a link to /system/bin/mksh, which is not the case on my 2.3.3 system.

Despite the fact that strings sh produces /etc/profile as one output, the file is not sourced.

Does anyone happen to know the old Android version and whether I have a chance to get /etc/profile or some other file sourced on shell startup? I thought it might be a permission problem but even rwxrwxr-x does not help.

Answer 1

As I wrote in the other question, adb shell does not start a login shell. Only login shells read /etc/profile.

As you can see in Android 2.3.3 sh source, main.c lines 175ff. only if argv[0] starts with a hyphen-minus is the shell considered a login shell. However, a few lines below (lines 185ff.) there is code to read the content of $ENV.

So you could trick it and enter the following code after entering adb shell mode:

ENV=/etc/profile sh

You can probably use exec to replace the current shell, but this is the shortest to type I can come up with, as you will have to type it every time.

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Alternatively, you can compile mksh for Android 2.3 (it works down to at least 1.5, if not older) manually (the Android.mk file is version-specific, unfortunately, so you’ll have to call Build.sh directly) and add the binary, then replace the default sh with it (I tested that first with Android 1.6; the newer the mksh version used the better, as early versions had bugs, e.g. preventing adb install from working).

Disclaimer: I’m the mksh developer.