Develop Reference

How to obtain IMEI via adb?

I'm trying to track devices, SIMs and airtime cards for test purposes. I have multiple devices plugged into a computer and since the recent update to Android 12, I am not able to get the device IMEI. The IMEI is basically the device's FCC-required serial number and can be obtained from the UI with relative ease, but how can I obtain it via ADB or in some automated method on multiple devices from multiple carriers and OEMs?
Prior to Android 12 FEB patch, I would use service call iphonesubinfo 1 or service call iphonesubinfo 4. But unfortunately after the update I receive back Result: Parcel(ffffffffc ffffffff 00000000 '................') whereas before I would receive a parcel containing the IMEI for processing via script.
Is there a way to get IMEI on Android 12+? I am trying to stay away from using an app. This is a simple thing, from a privileged user (adb shell). It seems like a basic necessity for tracking and logistics purposes.

This command works to obtain IMEI. It works by pressing the dialer key, then typing *#06#, then parsing the text on screen to find the IMEI Label and the next element which contains the actual IMEI. Finally it parses that element by removing all before text=" and all after ".
adb shell "imei=$(input keyevent KEYCODE_CALL;sleep 1;input text '*#06#'; uiautomator dump --compressed /dev/stdout|sed s/\>\<\/\\n/g|grep -A1 IMEI|tail -n1|sed -e 's/.*text=\"//' -e 's/\".*//'); echo ${imei}"
to get just the 16-digit IMEI without checksum, replace the final echo statement with echo ${imei:0:16}

I found a good solution for Samsung One UI
First, run the About menu
adb shell am start -a com.android.settings.ACTION_DEVICE_INFO_SETTINGS
Then dump the UI
adb shell uiautomator dump
View the dump file
adb shell cat /sdcard/window_dump.xml
The IMEI1 in the <node index="12" and IMEI 2 in <node index="13"

Is there a way to programatically check for used ports without looping?

I'm familiar with couple of methods to check for used ports on Android.
Loop over all possible ports, try creating a socket on each port, if socket creation fails port is used.
Use netstat command from shell which will list all open connections and used ports can be parsed from there.
Use cat /proc/net/tcp command from shell which is similar as netstat command.
Problem with 1st option is that looping over all possible ports is taking too much time, it's not efficient enough if I want to make sure that I'm getting all open ports.
Problem with 2nd and 3rd option is that (on non-rooted device) although shell command can be executed in shell (adb shell) and output is clearly seen, while trying to execute command from Java code in Android application, command output is empty string for cat /proc/net/tcp and only header is outputted from netstat command. I'm guessing that the problem are application permissions which are insufficient to run above commands.
Is there any other way of checking for used ports or am I doing something wrong by using commands from option 2 or 3?
EDIT:
To clarify, while using any command that should list connection info from adb shell this will work fine. However, if I'm trying to invoke any of the commands (same syntax as in adb shell) from my application's Java code, output of the command is empty string.
To get the process I tried using:
Runtime.getRuntime().exec(command);
new ProcessBuilder().command("sh", "-c", command).start();
E.g. output of netstat command (with any arguments) is as following:
Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State Active UNIX domain sockets (only servers) Proto RefCnt Flags Type State I-Node Path

How about:
netstat -ln | awk '/^tcp/ { split($4,arr,":");prts[arr[2]]="" } END { for (i in prts) { print i } }'
Take the netstat output and then using awk, concentrate on all lines beginning with tcp. Then split the 4th delimited field into a array called arr based on ":" as the delimiter. Put the second index of the array (port number) in another array prts as the index. At the end, loop through the prts array and print the indexes (ports)

Get device information (such as product, model) from adb command

One way to achieve this is as follows:
adb devices -l
example output:
123abc12 device product:<id> model:<id> device:<id>
456abc45 device product:<id> model:<id> device:<id>
But this list's out all devices connected, but I want to get the information for a specific device.I want information only about "123abc12". The output should be:
123abc12 device product:<id> model:<id> device:<id>
The second device should not be shown.
I have the device name i.e 123abc12, and it can be used to get the required information, but I don't know how.
Thanks.

The correct way to do it would be:
adb -s 123abc12 shell getprop
Which will give you a list of all available properties and their values. Once you know which property you want, you can give the name as an argument to getprop to access its value directly, like this:
adb -s 123abc12 shell getprop ro.product.model
The details in adb devices -l consist of the following three properties: ro.product.name, ro.product.model and ro.product.device.
Note that ADB shell ends lines with \r\n, which depending on your platform might or might not make it more difficult to access the exact value (e.g. instead of Nexus 7 you might get Nexus 7\r).

Why don't you try to grep the return of your command ?
Something like :
adb devices -l | grep 123abc12
It should return only the line you want to.

Android regular user login loses group information when su to another user in an ssh session

What I'm doing:
I've built GNU emacs for native use on an phone.
I run emacs in daemon mode on the phone, so I connect to it anytime with emacsclient, to continue working with regular files, run processes, etc.
When logging in from the terminal on the phone, I'm currently user 10157, everything works:
$ id
uid=10157(10157) gid=10157(10157)
groups=10157(10157),1015(1015),1023(1023),1028(1028),3003(3003)
When I connect via ssh to the phone from a PC (I use DigiSSHd on the phone), it logs me in as a regular user 10282, everything works:
$ id
uid=10282 gid=10282 groups=1015(1015),1023(1023),1028(1028),3003(3003)
Emacs runs fine etc. However, this way I can't connect via emacsclient to the emacs process running under user 10157. This is desirable, since I don't want to start two emacs processes, since I want to continue working with files that I have open in emacs under user 10157.
Therefore:
$ su - 10157
Fine, I can run emacs etc. However, I cannot access the web.
$ ping -c1 google.com
You must have internet permissions to use ping. Aborting.
$ id
uid=10157(10157) gid=10157(10157) groups=10157(10157)
Thus I'm no longer in group 3003, necessary for internet access, besides other groups also.
Why does this group info get stripped, and how can I remedy this, so I can continue accessing the web when su as this user under ssh?

When i run the command:
busybox --list
I don't see su in the list.
su --help
shows Superuser.apk in the help text. It means su is provided by Superuser app.
I followed the steps described by you and i could su as another user and still have internet permission as shown below.
I have the following apps installed.
BusyBox v1.18.5-Stericson
Superuser v3.0.7
Terminal Emulator v1.0.45
SSHDroid v1.9.6
Suggestion:
I think the issue is with su on your device. You may try this one.
https://play.google.com/store/apps/details?id=com.noshufou.android.su
If i just use adb shell without running SSHDroid still i can su as another user with internet permission.
Note: The BusyBox id command doesn't show groups information always.

According to the standard man page for su (from a linux box)
When - is used, it must be specified as the last su option. The other forms (-l and --login) do not have this restriction.
Based on that, try
$ su 10157 -

I'm probably missing something here because this seems way too obvious but why not just 'sudo -u 10157' your emacs program?
you'd still have access to the net and your emacs would be working. or did I miss something important?

Permissions are not environment variables that can be inherited via su -.
Moreover, gid are are hard coded and their associations with each APP uid cannot be changed after installation.
10157 should be the uid of the DigiSSHd application, thus you could try to rebuild it after changing the AndroidManifest.xml to require the proper permission.
You can find something useful here and here.
The same should work for BusyBox (see here).
However, you could open some security hole by enabling NETWORK access through such applications.

How to change 3g dns setting on Android?

I want to change 3G dns setting on Android 2.1 device. I managed to install busybox on my device, i can also get dns information by using adb shell getprop | grep dns. The only problem is that it shows me net.pdp0.dns1 and net.pdp0.dns2, not net.rmnet0.dns1 and net.rmnet0.dns1 so i can't change the setting.
I know that net.rmnet0.dns1 is for 3G connection, so what about net.pdp0.dns1? How can i change to net.rmnet0.dns1?
Thanks

Android DSN file contains in following directory:
In android file system
system/etc/dhcpcd/dhcpcd-hooks/20-dns.conf
20-dns.conf file contains dns setting, you can modify this file by following way:
# Set net.<iface>.dnsN properties that contain the
# DNS server addresses given by the DHCP server.
set_dns_props()
{
case "${new_domain_name_servers}" in
"") return 0;;
esac
count=1
for i in 1 2 3 4; do
setprop dhcp.${interface}.dns${i} ""
done
count=1
for dnsaddr in ${new_domain_name_servers}; do
setprop dhcp.${interface}.dns${count} ${dnsaddr}
count=$(($count + 1))
done
setprop dhcp.eth0.dns1 8.8.8.8
setprop dhcp.eth0.dns2 8.8.8.4
}
unset_dns_props()
{
for i in 1 2 3 4; do
setprop dhcp.${interface}.dns${i} ""
done
}
case "${reason}" in
BOUND|INFORM|REBIND|REBOOT|RENEW|TIMEOUT) set_dns_props;;
EXPIRE|FAIL|IPV4LL|RELEASE|STOP) unset_dns_props;;
esac
(Note:Please take backup of origin file , if you need origin file)
set your dns in following line
setprop dhcp.eth0.dns1 8.8.8.8
setprop dhcp.eth0.dns2 8.8.8.4

It may help if you state the kind of device you have. From what I've read online, Samsung devices use the pdp0 interface names (it may be that this is the way Samsung refers to the 3G connections). Personally I have been using all HTC devices and the 3G interface is always rmnet0.
Is your phone rooted? You may not be able to set properties in the "net" category without root permissions.
If you are root, have you tried "setprop net.pdp0.dns1 "? Also, does "adb shell getprop | grep dns" give you "net.dns1"? I believe this is the default way Android looks up DNS servers. You may want to set this property as well.
You can test if it is working by running nslookup, it will show you the server it is querying.
Good luck,
B-Rad