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I'm accustomed to running scripts on boot in Linux, but I'm not sure how to do this in Android. I'd like to start my SSH daemon on start, so I'll always be able to connect. How can I run an arbitrary script on Android boot? It'd be preferable to do this outside of Dalvik.

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3 Answers 3

up vote 11 down vote accepted

While looking around my Android filesystem, I found that it did, in fact have a /etc/init.d/ directory. After peeking around in there, I found /etc/init.d/20userinit with the following lines:

if [ -e /data/local/userinit.sh ];
then 
    log -p -i -t userinit "Executing /data/local/userinit.sh";
    busybux chmod +x /data/local/userinit.sh;
    logwrapper /system/bin/sh /data/local/userinit.sh;
    setprop cm.userinit.active 1;
fi;

This being, of course, exactly what I needed, I wrote the following script on my computer then pushed it to my device:

#!/system/bin/sh 

dropbear -s -g 

(pushed to device via scp userinit.sh phone:/data/local/userinit.sh, mind you :] )

Rebooted the device, then ran ps | grep "[d]ropbear", and sure enough, it's running. Coolness!

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1  
Great. Apparently CM has its own way of doing things. –  Matthew Read Mar 2 '11 at 21:57
    
Yep, weird, but it works. –  Naftuli Tzvi Kay Mar 2 '11 at 22:01
1  
sorry to bump an old question, i tried adding /etc/init.d/99mount with content mount -o bind /emmc /mnt/sdcard/external_sd/ however it isn't being executed at startup –  Joe Apr 18 '12 at 18:47
    
@Joe did you find an answer? I have the same issue. –  Shimmy Nov 27 '13 at 10:04
    
@Shimmy my problem was solved by executing chmod o+x to the file. hope it helps. –  Joe Nov 27 '13 at 14:35

/data/init.sh runs at boot, if you have root you can edit it as you like. Be careful ;)

Edit: Apparently you might need to shoehorn the edited script into the boot image as well. Info on how to do that here: http://forum.xda-developers.com/showthread.php?t=443994

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1  
Eee! Thanks :) I'll "be careful." –  Naftuli Tzvi Kay Mar 2 '11 at 21:21
1  
Yeah, I can't seem to find this file on my Nexus One running CM7-RC1. I'll see if a find / -name "init.sh" turns anything up. Are there any other scripts that run on boot? –  Naftuli Tzvi Kay Mar 2 '11 at 21:32
    
You should have an /etc/init.rc which starts the shell. It should call init.sh but if it doesn't you can just make it call your own script. –  Matthew Read Mar 2 '11 at 21:40
    
Unfortunately, I don't have that script either, but I did find a solution. –  Naftuli Tzvi Kay Mar 2 '11 at 21:49
2  
What version of Android is it ? 4.3 does have /data but no /data/init/.sh or /etc/init.rc. Grep does not find any interesting instance of the string init in /etc (even recursive). –  Stéphane Gourichon Dec 7 '13 at 18:32

Look to /etc/ directory. Usually it is placed in /system/ partition which you can mount as RW:

$ ls -l /etc
lrwxrwxrwx 1 root root 11 Jan 1  2009 /etc -> /system/etc
$ su
$ mount -o remount,rw /system
$ chmod o+w /system/etc  # for "adb push"

and later remount RO:

$ chmod o-w /system/etc
$ mount -o remount,ro /system

Now your task to find executable or *rc file which you modify to achieve your goal:

$ find /etc -type f -perm +110
$ find /etc -name "*rc"
$ find /etc -name "init*"
$ grep -R /data /etc
$ grep -R /system /etc

Google about each candidate to get know how this file was used.

Good candidate for including custom scripts are lines from:

$ grep service /init*.rc

As each device unique you may need to do own guess about search criteria...

For example I found /etc/mkshrc which used by Korn shell. I update this file to extend PATH env var and now each time I do adb shell I have Busybox symlinks in my PATH!

See also hard way (if you have no luck with finding magic file): http://stackoverflow.com/questions/9768103/make-persistent-changes-to-init-rc

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