ZEWAREN.NET

Let's install sympa with postfix on a FreeBSD jail.

Install sympa

Install the port:

# make -C /usr/ports/mail/sympa install clean

Make sure the syslog entries of sympa are stored into a separate log file:

# mkdir -p /usr/local/etc/syslog.d
# echo "local1.*       /var/log/sympa" > /usr/local/etc/syslog.d/sympa
# service syslogd reload

Make sure sympa is allowed to write into its data and bounce directory:

# chown root:sympa /usr/local/share/sympa/list_data
# chmod 770 /usr/local/share/sympa/list_data
# chown root:sympa /usr/local/share/sympa/bounce
# chmod 770 /usr/local/share/sympa/bounce

Make sure sympa is allowed to write into its config directory:

# chown root:sympa /usr/local/etc/sympa
# chmod 770 /usr/local/etc/sympa
# chown root:sympa /usr/local/etc/sympa/sympa.conf

In my opinion, this is plain stupid. Running software should not be able to edit its config files.

Make sure sympa is allowed to write into its shared directory:

# chown root:sympa /usr/local/share/sympa
# chmod 705 /usr/local/share/sympa

Also, I think this is bad practice.

Make sure sympa is allowed to write into the system mail config directory:

# chown root:sympa /etc/mail
# chmod 770 /etc/mail

Do I like this? Absolutely not.
In particular, sympa needs to write into /etc/mail/aliases.db. If that file already exists on your system, give it a good chown as well.

Edit /usr/local/etc/sympa/sympa.conf to your need. Here's a basic configuration:

domain  sympa.example.com
listmaster  admin@example.com
wwsympa_url http://sympa.example.com/wws
cookie add69524c8a75f47c05ccb47f96c9195
db_type mysql
db_host 192.168.0.2
db_name sympa
db_user sympa
db_passwd Ujzz6YVdEXppajM
static_content_path /usr/local/share/sympa
static_content_url /static-sympa
sendmail_aliases /usr/local/share/sympa/list_data/sympa_aliases

Configuring the database of sympa is out of the scope of this article. Here I'm simply using MySQL.

Enable the service:

# sysrc sympa_enable="YES"

Start the service:

# service sympa start

Installing and configuring postfix

Install postfix:

# Make -C /usr/ports/mail/postfix install clean

Edit the main config (/usr/local/etc/postfix/main.cf) and configure a transport and a map file for sympa:

myhostname = sympa.example.com
mydomain = sympa.example.com
mydestination = localhost, sympa.example.com
recipient_delimiter = +
mailbox_size_limit = 0
transport_maps = regexp:/usr/local/etc/postfix/transport_regexp_sympa
sympa_destination_recipient_limit = 1
sympabounce_destination_recipient_limit = 1
alias_maps = hash:/etc/mail/aliases,hash:/usr/local/share/sympa/list_data/sympa_aliases
alias_database = hash:/etc/mail/aliases,hash:/usr/local/share/sympa/list_data/sympa_aliases

/usr/local/etc/postfix/transport_regexp_sympa:

/^.*\-owner@sympa\.example\.com$/ sympabounce:
/^.*\@sympa\.example\.com$/       sympa:

Edit the transport file (/usr/local/etc/postfix/master.cf) and add transports to sympa:

sympa   unix        -   n   n   -   -   pipe
    flags=R user=sympa argv=/usr/local/libexec/sympa/queue ${recipient}
sympabounce unix    -   n   n   -   -   pipe
    flags=R user=sympa argv=/usr/local/libexec/sympa/bouncequeue ${recipient}

Enable and start postfix:

# sysrc postfix_enable="YES"
# service postfix start

Installing the web interface (wwsympa)

Install dependencies:

# make -C /usr/ports/databases/p5-DBD-mysql install clean
# make -C /usr/ports/www/p5-CGI-Fast install clean

Install nginx and fcgiwrap:

# make -C /usr/ports/www/nginx install clean
# make -C /usr/ports/www/fcgiwrap install clean

Configure a profile in /etc/rc.conf and enable the service:

fcgiwrap_enable="YES"
fcgiwrap_profiles="sympa"
fcgiwrap_sympa_socket="unix:/tmp/fcgiwrap_sympa.sock"
fcgiwrap_sympa_user="sympa"
fcgiwrap_sympa_socket_owner="sympa"
fcgiwrap_sympa_socket_group="www"
fcgiwrap_sympa_socket_mode="0770"

Start the service and check that it's listening correctly:

# service fcgiwrap start
# sockstat -l | grep fcgiwrap
sympa    fcgiwrap   79058 0  stream /tmp/fcgiwrap_sympa.sock

Add a server to the configuration files of nginx:

server {
   listen 80;
   server_name sympa.example.com;
   access_log /var/log/nginx/sympa-access.log;
   error_log /var/log/nginx/sympa-error.log;
   index wws/;
   location /static-sympa {
       alias /usr/local/share/sympa;
       access_log off;
   }

   location / {
     gzip off;
     fastcgi_pass   unix:/tmp/fcgiwrap_sympa.sock;
     fastcgi_split_path_info ^(/wws)(.+)$;
     fastcgi_param  QUERY_STRING       $query_string;
     fastcgi_param  REQUEST_METHOD     $request_method;
     fastcgi_param  CONTENT_TYPE       $content_type;
     fastcgi_param  CONTENT_LENGTH     $content_length;
     fastcgi_param  PATH_INFO          $fastcgi_path_info;
     fastcgi_param  SCRIPT_NAME        $fastcgi_script_name;
     fastcgi_param  REQUEST_URI        $request_uri;
     fastcgi_param  DOCUMENT_URI       $document_uri;
     fastcgi_param  DOCUMENT_ROOT      $document_root;
     fastcgi_param  SERVER_PROTOCOL    $server_protocol;
     fastcgi_param  GATEWAY_INTERFACE  CGI/1.1;
     fastcgi_param  SERVER_SOFTWARE    nginx;
     fastcgi_param  REMOTE_ADDR        $remote_addr;
     fastcgi_param  REMOTE_PORT        $remote_port;
     fastcgi_param  SERVER_ADDR        $server_addr;
     fastcgi_param  SERVER_PORT        $server_port;
     fastcgi_param  SERVER_NAME        $server_name;
     fastcgi_param  REMOTE_USER        $remote_user;
     fastcgi_param  SCRIPT_FILENAME    /usr/local/libexec/sympa/wwsympa-wrapper.fcgi;
     fastcgi_param  HTTP_HOST          sympa.example.com;
     fastcgi_intercept_errors on;
   }
}

Enable and start nginx:

# sysrc nginx_enable="YES"
# service nginx start

The web interface is now available.

If everything went well, you can now create a list:

You can check that the alias file was updated correctly:

# cat /usr/local/share/sympa/list_data/sympa_aliases
## This aliases file is dedicated to Sympa Mailing List Manager
## You should edit your sendmail.mc or sendmail.cf file to declare it
#------------------------------ test_list: list alias created 22 Aug 2017
test_list: "| /usr/local/libexec/sympa/queue test_list@sympa.example.com"
test_list-request: "| /usr/local/libexec/sympa/queue test_list-request@sympa.example.com"
test_list-editor: "| /usr/local/libexec/sympa/queue test_list-editor@sympa.example.com"
#test_list-subscribe: "| /usr/local/libexec/sympa/queue test_list-subscribe@sympa.example.com"
test_list-unsubscribe: "| /usr/local/libexec/sympa/queue test_list-unsubscribe@sympa.example.com"
test_list-owner: "| /usr/local/libexec/sympa/bouncequeue test_list@sympa.example.com"

Test everything

Send a test email:

echo "Est-elle brune, blonde ou rousse ? - Je l'ignore." | mail -s "Test email" test_list@sympa.example.com

Check /var/log/maillog:

Dec  7 21:49:16 sympa1 postfix/qmgr[47576]: 987058465: from=<user1@example.com>, size=1378, nrcpt=1 (queue active)
Dec  7 21:49:17 sympa1 postfix/pipe[76920]: 987058465: to=<test_list@sympa.example.com>, relay=sympa, delay=1.1, delays=0.02/0/0/1.1, dsn=2.0.0, status=sent (delivered via sympa service)
Dec  7 21:49:17 sympa1 postfix/qmgr[47576]: 987058465: removed
Dec  7 21:49:17 sympa1 postfix/smtpd[76916]: connect from unknown[10.9.0.101]
Dec  7 21:49:18 sympa1 postfix/qmgr[47576]: 1119E8478: from=<test_list-owner@sympa.example.com>, size=2274, nrcpt=1 (queue active)
Dec  7 21:49:18 sympa1 postfix/smtp[76926]: 1119E8478: to=<user2@example.com>, relay=mail1.example.net[198.51.100.35]:25, delay=0.77, delays=0.32/0.01/0.08/0.36, dsn=2.0.0, status=sent (250 2.0.0 Ok: queued as 7E4E45EA7)
Dec  7 21:49:18 sympa1 postfix/qmgr[47576]: 1119E8478: removed

Check /var/log/messages:

Dec 07 21:49:16 sympa1 sympa_msg[47458]: notice Sympa::Spindle::ProcessIncoming::_twist() Processing Sympa::Message <test_list@sympa.example.com.1512683356.76921>; envelope_sender=user1@example.com; message_id=eme4db733a-c660-45fd-bdf5-37968cdbdc1e@rasa; sender=user1@example.com
Dec 07 21:49:16 sympa1 sympa_msg[47458]: notice Sympa::Spool::store() Sympa::Message <test_list@sympa.example.com.1512683356.76921> is stored into Sympa::Spool::Archive as <1512683356.1512683356.964608.test_list@sympa.example.com,47458,8945>
Dec 07 21:49:16 sympa1 sympa_msg[47458]: notice Sympa::Spool::store() Sympa::Message <test_list@sympa.example.com.1512683356.76921> is stored into Sympa::Spool::Digest <test_list@sympa.example.com> as <1512683356.1512683356.978756,47458,7735>
Dec 07 21:49:16 sympa1 sympa_msg[47458]: notice Sympa::Bulk::store() Message Sympa::Message <test_list@sympa.example.com.1512683356.76921> is stored into bulk spool as <5.5.1512683356.1512683356.985672.test_list@sympa.example.com_z,47458,6615>
Dec 07 21:49:16 sympa1 sympa_msg[47458]: notice Sympa::Spindle::ToList::_send_msg() No VERP subscribers left to distribute message to list Sympa::List <test_list@sympa.example.com>
Dec 07 21:49:18 sympa1 bulk[47461]: notice Sympa::Mailer::store() Done sending message Sympa::Message <5.5.1512683356.1512683356.985672.test_list@sympa.example.com_z,47458,6615/z> for Sympa::List <test_list@sympa.example.com> (priority 5) in 2 seconds since scheduled expedition date

In this series of blog posts, we're going to create a Android build server for continuous integration on FreeBSD.

• Part one will explain how to build Android APKs using Gradle on FreeBSD using the Linux emulation.
• Part two will explain how to configure Gitlab-CI to be able to run builds automatically for each commit.
• Part three (this post) will explain how to configure Jenkins to be able to run builds and email the APKs to people.

Requirements

We want people from our project to be able to build APKs of a Android app and get them by email once they're built. People should be able to configure their app with some Jenkins parameters.

This post does not explain the basics of Jenkins. You should read the documentation if it's your first time using it.

You will need the following plugins:

• SSH Slaves.
• Gradle.
• Email Extension.

Creating the node

In this scenario, I'm going to assume our FreeBSD build server is not on the same host as the Jenkins.

In consequence, we need to link the two systems by installing a Jenkins slave-node on the build system.

Preparing the server

On your Android build system, create a new user:

# pw group add -n jenkins-slave
# pw user add -n jenkins-slave -g jenkins-slave

Create a SSH key pair:

# ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/home/jenkins-slave/.ssh/id_rsa): jenkins-slave-id_rsa
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in jenkins-slave-id_rsa.
Your public key has been saved in jenkins-slave-id_rsa.pub.

Add the public key to your SSH's authorized_keys. That will be how Jenkins connect to the slave.

# mkdir ~/.ssh/
# cat jenkins-slave-id_rsa.pub >> ~/.ssh/authorized_keys

Create the node on Jenkins

Go to "Manage Jenkins" -> "Manage credentials", and add a new "SSH Username with private key".
Put the private key you generated earlier there and configure the rest.

Go to "Manage Jenkins" -> "Manage Nodes" and create a new node.

Configure the node with the right host, port and home directory. Set the location of the java executable, or Jenkins will only try to find it in /bin or /usr/bin and it won't work.

If everything goes well, the master node should connect to the server, install its JAR and start the slave node.

# ls
jenkins-slave-pepper-id_rsa     jenkins-slave-pepper-id_rsa.pub slave.jar                       workspace

# ps -U jenkins-slave
  PID TT  STAT     TIME COMMAND
66474  -  IJ    0:08.67 sshd: jenkins-slave@notty (sshd)
66478  -  IsJ  11:51.54 /usr/local/openjdk8/bin/java -jar slave.jar

Configuring the job

Create a new job, give it a nice name, and start the configuration.

The parameters

Click on "This build is parameterized", and add as many parameters as you want. You will be able to use these parameters as Jenkins variable everywhere later in the build.

Here I have two parameters:

• One to specify what kind of build I want: debug, staging, production, etc.
• One that specify where I want to APK to be sent once it's built.

Fetching the code

Configure Jenkins to fetch the source code of the app where it's located.

Here I'll fetch it from git.

Building the app

Add the required environment variables to the build.

Add a gradle build script, and invoke the tasks to build your app. Here you can use the parameters you set up at the beginning of the config.

You can build without the gradle plugin if you want. It only displays the build nicer but is strictly non essential.

Email the APKs once they're built

Add a post build step: "Editable Email Notification".

Put the recipient chosen by the user from the parameters into the list of recipients, customize the sender, reply-to, subject, content, etc.

Add the APK files as attachments.

Don't forget to configure the triggers to send the email if the build succeeds. By default, emails are only sent on failure.

Testing

Start a build. If everything goes well, you should receive the resulting APK by email a few seconds after the build is done.

In this series of blog posts, we're going to create a Android build server for continuous integration on FreeBSD.

• Part one (this post) will explain how to build Android APKs using Gradle on FreeBSD using the Linux emulation.
• Part two will explain how to configure Gitlab-CI to be able to run builds automatically for each commit.
• Part three will explain how to configure Jenkins to be able to run builds and email the APKs to people.

I'll be using a normal 10.2-RELEASE:

# uname -a
FreeBSD androidbuild 10.2-RELEASE-p11 FreeBSD 10.2-RELEASE-p11 #0: Wed Jan 27 15:56:01 CET 2016     root@androidbuild:/usr/obj/usr/src/sys/GENERIC  amd64

Parts of this posts are duplicate from my old post on how to build APKs on FreeBSD.

Step 1: installing the system dependencies

We're going to install many packages, including a lot of GNU-style one. So if you care about having your systems cleans, I suggest your do all this in a jail.

Install gradle:

# make -C /usr/ports/devel/gradle/ install clean

Go drink the longest coffee you can brew. That stuff installs a lot of dependencies.

Install bash and link it to /bin/bash:

# make -C /usr/ports/shells/bash install clean
# ln -s /usr/local/bin/bash /bin/bash

Install git:

# make -C /usr/ports/devel/git install clean

Install python:

# make -C /usr/ports/lang/python install clean

Create a nice user to execute the builds:

# pw useradd androidbuild
# mkdir /home/androidbuild
# chown androidbuild:androidbuild /home/androidbuild

Load FreeBSD's Linux emulation system and install a base CentOS 6 system:

# kldload linux
# cd /usr/ports/emulators/linux_base-c6 && make install distclean

The latest version of the build tools (24.0.0) use 64bit binaries and libraries. If you want to be able to build your apks with them, you'll also need the 64bit Linux emulation. In that case, you must be running a FreeBSD version >= 10.3. In that case, you should do instead:

# kldload linux
# kldload linux64
echo "OVERRIDE_LINUX_BASE_PORT=c6_64" >> /etc/make.conf
echo "OVERRIDE_LINUX_NONBASE_PORTS=c6_64" >> /etc/make.conf
# cd /usr/ports/emulators/linux_base-c6 && make install distclean

If you alread had the 32 bit CentOS base, uninstall the port, remove the /compat/linux files and reinstall the port again after setting the two entries in make.conf.

Step 2: setting-up the Android SDK

Download the SDK

Fetch and extract the latest version of the Linux SDK:

% fetch 'https://dl.google.com/android/android-sdk_r24.4.1-linux.tgz'
% tar xzf android-sdk_r24.4.1-linux.tgz
% setenv ANDROID_HOME /home/androidbuild/android-sdk-linux/

Patch the SDK

As it is now, the SDK will download build tools for Windows, since it obviously won't recognize our FreeBSD.
Since we're going to use the Linux emulation, we need to path the system so that it downloads Linux binaries:

Download the source of the SDK base:

% git clone https://android.googlesource.com/platform/tools/base

Apply the following patch:

diff -r -u a/common/src/main/java/com/android/SdkConstants.java b/common/src/main/java/com/android/SdkConstants.java
--- a/common/src/main/java/com/android/SdkConstants.java        2016-09-06 07:56:56.325948102 +0000
+++ b/common/src/main/java/com/android/SdkConstants.java        2016-09-06 07:58:10.721944140 +0000
@@ -635,6 +635,8 @@
             return PLATFORM_WINDOWS;
         } else if (os.startsWith("Linux")) {                //$NON-NLS-1$
             return PLATFORM_LINUX;
+        } else if (os.startsWith("FreeBSD")) {              //$NON-NLS-1$
+            return PLATFORM_LINUX;
         }

         return PLATFORM_UNKNOWN;
diff -r -u a/sdklib/src/main/java/com/android/sdklib/internal/repository/archives/ArchFilter.java b/sdklib/src/main/java/com/android/sdklib/internal/repository/archives/ArchFilter.java
--- a/sdklib/src/main/java/com/android/sdklib/internal/repository/archives/ArchFilter.java      2016-09-06 07:56:56.828948347 +0000
+++ b/sdklib/src/main/java/com/android/sdklib/internal/repository/archives/ArchFilter.java      2016-09-06 07:58:35.160941890 +0000
@@ -216,6 +216,8 @@
             hostOS = HostOs.WINDOWS;
         } else if (os.startsWith("Linux")) {                //$NON-NLS-1$
             hostOS = HostOs.LINUX;
+        } else if (os.startsWith("FreeBSD")) {                //$NON-NLS-1$
+            hostOS = HostOs.LINUX;
         }

         BitSize jvmBits;

Rebuild the patched files.

% javac common/src/main/java/com/android/SdkConstants.java
% javac sdklib/src/main/java/com/android/sdklib/internal/repository/archives/ArchFilter.java -cp "sdklib/src/main/java:common/src/main/java:annotations/src/main/java"

Replace the files inside the jar.

% cd sdklib/src/main/java/ && jar uf ${ANDROID_HOME}/tools/lib/sdklib.jar com/android/sdklib/internal/repository/archives/ArchFilter.class
% cd common/src/main/java && jar uf ${ANDROID_HOME}/tools/lib/common.jar com/android/SdkConstants.class

See this patch on the Android website: https://android-review.googlesource.com/#/c/100271/

Download the SDK packages and set-up the build tools

Go to the tool directory:

% cd ${ANDROID_HOME}/tools/

In the example, we're going to build an APK thats uses API version 23.
Let's download the right packages:

% ./android list sdk -u -a
[...]
7- Android SDK Build-tools, revision 23.0.3
31- SDK Platform Android 6.0, API 23, revision 3
119- Google APIs, Android API 23, revision 1
% ./android update sdk -u -a -t tools,platform-tools,7,31,119

Let's find the Linux binaries in the build tools, and brand them as such:

% find build-tools/23.0.3/ -maxdepth 1 -type f -print0 | xargs -0 -n 10 file | grep "ELF"
build-tools/23.0.3/mipsel-linux-android-ld:  ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.8, stripped
build-tools/23.0.3/arm-linux-androideabi-ld: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.8, stripped
build-tools/23.0.3/llvm-rs-cc:               ELF 32-bit LSB shared object, Intel 80386, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.24, BuildID[sha1]=8a4ffbc0e197147c4e968722e995605e1d06ea88, not stripped
build-tools/23.0.3/i686-linux-android-ld:    ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.8, stripped
build-tools/23.0.3/bcc_compat:               ELF 32-bit LSB shared object, Intel 80386, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.24, BuildID[sha1]=d565d03b7bafd03d335bdd246832bb31c7cca527, not stripped
build-tools/23.0.3/aapt:                     ELF 32-bit LSB shared object, Intel 80386, version 1 (GNU/Linux), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.24, BuildID[sha1]=cfb63b4ad11d0c2d59f10329f0116706e99bf72e, not stripped
build-tools/23.0.3/aidl:                     ELF 32-bit LSB shared object, Intel 80386, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.24, BuildID[sha1]=3cbd3d742040d61877a3c6544778bf4701b2f62d, not stripped
build-tools/23.0.3/aarch64-linux-android-ld: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.8, stripped
build-tools/23.0.3/split-select:             ELF 32-bit LSB shared object, Intel 80386, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.24, BuildID[sha1]=b3bfb153d0ffaef6ed84c316ff682381ba8d75b2, not stripped
build-tools/23.0.3/dexdump:                  ELF 32-bit LSB shared object, Intel 80386, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.24, BuildID[sha1]=a678a8163a2483107d285ffdc94fdde0d4fb2178, not stripped
build-tools/23.0.3/zipalign:                 ELF 32-bit LSB shared object, Intel 80386, version 1 (GNU/Linux), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.24, BuildID[sha1]=7d64216663df9fd3b4048952d095fbd07cb4284f, not stripped

% find build-tools/24.0.3/ -maxdepth 1 -type f -print0 | xargs -0 -n 10 file | grep "ELF" | awk 'BEGIN { FS = ":" } ; {print $1}' | xargs brandelf -t Linux
% find build-tools/24.0.3/ -maxdepth 1 -type f -print0 | xargs -0 -n 10 file | grep "ELF" | awk 'BEGIN { FS = ":" } ; {print $1}' | xargs chmod +x

The SDK is now configured and we should be able to build our apps there.

Step 3: building the APK

Fetch the sources of your app:

% git clone 'https://git.example.org/android-app'
% cd android-app

Be sure to have set environment variable ANDROID_HOME to the SDK location.
Start gradle and see if it complains.

% gradle tasks
------------------------------------------------------------
All tasks runnable from root project
------------------------------------------------------------

Android tasks
-------------
androidDependencies - Displays the Android dependencies of the project.
signingReport - Displays the signing info for each variant.
sourceSets - Prints out all the source sets defined in this project.
[...]
To see all tasks and more detail, run gradle tasks --all

To see more detail about a task, run gradle help --task <task>

BUILD SUCCESSFUL

Total time: 14.839 secs

Gradle is happy, let's try a build:

% gradle assembleRelease
[...]
BUILD SUCCESSFUL

Total time: 2 mins 24.784 secs

Let's look at the build output:

% ls Truc/build/outputs/apk/
truc-app-release-unaligned.apk   truc-app-release.apk

Success!

The BeagleBone Black's SoC (AM335x) includes a watchdog timer, that will reset the whole board is it isn't pingged regularly.

Let's see if we can stop that thing running the latest Debian GNU/Linux to date.

# uname -a
Linux beaglebone 4.4.9-ti-r25 #1 SMP Thu May 5 23:08:13 UTC 2016 armv7l GNU/Linux
root@beaglebone:~# cat /etc/debian_version
8.4

Ever since this commit, the OMAP watchdog driver has the magic close feature enabled. This means that closing the timer's device won't stop the timer from ticking. The only way to stop it is to send to it the magic character 'V' (a capital 'v').

# wdctl /dev/watchdog
wdctl: write failed: Invalid argument
Device:        /dev/watchdog
Identity:      OMAP Watchdog [version 0]
Timeout:       120 seconds
Timeleft:      119 seconds
FLAG           DESCRIPTION               STATUS BOOT-STATUS
KEEPALIVEPING  Keep alive ping reply          0           0
MAGICCLOSE     Supports magic close char      0           0
SETTIMEOUT     Set timeout (in seconds)       0           0

This feature is particularly useful if you want the watchdog timer to only be active when a specific application is running, and if you then want it to be stopped when the application is stopped normally.

Unfortunately, the kernel can be configure with a mode called "no way out", which means that even tough the magic close feature of the driver is enabled, it won't be honored at all, and you are doomed to ping your timer until the end of time once you opened the device.

# cat /proc/config.gz | gunzip | grep CONFIG_WATCHDOG_NOWAYOUT
CONFIG_WATCHDOG_NOWAYOUT=y

On a kernel version 3.8, the feature was not enabled:

$ cat /proc/config.gz | gunzip | grep CONFIG_WATCHDOG_NOWAYOUT
# CONFIG_WATCHDOG_NOWAYOUT is not set

So, how do we stop that thing?

Well, you can see in the code of the driver that the default value of the kernel can be overridden by a module param:

static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
	"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

Edit the boot configuration in /boot/uEnv.txt and add set that parameter to 0 in the cmdline:

cmdline=coherent_pool=1M quiet cape_universal=enable omap_wdt.nowayout=0

Reboot the board, and check that the loaded command line was changed correctly:

# cat /proc/cmdline
console=tty0 console=ttyO0,115200n8 root=/dev/mmcblk0p1 rootfstype=ext4 rootwait coherent_pool=1M quiet cape_universal=enable omap_wdt.nowayout=0

That's it. Now if you send a 'V' to the watchdog right before closing it, it will be stopped.