What is Wallindle

Wallindle is a native wallabag client for e-ink kindle. Wallindle fetch new articles in your Wallabag and add them to your kindle's unread ebooks.

The standard way to "read-later" an article on the kindle is using a "read-later" online service and transmit the saved article to the kindle using Amazon "by-email" transmission. It works very well and with a very easy minimal setup !

However it relies on a two services which can be shut down at any moment. Wallabag can be your very own "read-later" service and in this case, Wallindle allows your e-ink kindle fetching saved articles autonomously !

What do I need ?

• An e-ink Kindle, jailbroken. If you don't undestand instructions, please do not attempt a jailbreak.

• A Wallabag account (either your own instance or a official one) with some recent articles !

Remerciements :

• Kindle jailbreak scene
• Gentoo Project for kindle toolchain
• Wallabag team
• Jsmn library for parsing jason in C
• libcurl team
• Hervé for Wallabag support

Running Wallindle

Building binary

• You need a "arm-linux-gnueabi" compiler. You can easily find one in your linux distro repository.

If you are a "Gentoo Linux" user I strongly recommend you builduing your own toolchain with crossdev :

$ crossdev --stable -v -t arm-linux-gnueabi

• Get Wallindle sources :

git clone https://github.com/cekage/wallindle.git

• Download libcurl, libssl, libcrypt and libcrypto from the kindle using download_kindle_lib.sh :

$ cat download_kindle_lib.sh 
#!/usr/bin/env bash

DEST=lib/curlkindle/lib
SRC=/usr/lib
KINDLEIP=192.168.15.244

for lib in ssl curl crypt
do
	scp root@${KINDLEIP}:${SRC}/lib${lib}*so ${DEST}
done;

$ ./download_kindle_lib.sh 


Welcome to Kindle!

root@192.168.15.244's password: 
libssl.so              100%  287KB   6.0MB/s 286.7KB/s   00:00 


Welcome to Kindle!

root@192.168.15.244's password: 
libcurl.so             100%  208KB   5.9MB/s 207.9KB/s   00:00 


Welcome to Kindle!

root@192.168.15.244's password: 
libcrypt.so            100%   38KB   4.6MB/s  37.5KB/s   00:00 
libcrypto.so           100% 1393KB   6.2MB/s   1.4MB/s   00:00

$ ls -alh lib/curlkindle/lib/*.so
-rwxr-xr-x 1 k users 1,4M  3 sept. 20:53 lib/curlkindle/lib/libcrypto.so
-rw-r--r-- 1 k users  38K  3 sept. 20:53 lib/curlkindle/lib/libcrypt.so
-rwxr-xr-x 1 k users 208K  3 sept. 20:53 lib/curlkindle/lib/libcurl.so
-rwxr-xr-x 1 k users 287K  3 sept. 20:53 lib/curlkindle/lib/libssl.so

• Adjust binaries path and name in Makefile
• Make kindle native binary :

$ make arm
arm-linux-gnueabi-gcc -O0 -std=iso9899:1999   -mfpu=vfp -mfloat-abi=softfp -mtune=cortex-a8 -march=armv7-a wallindle.c  configmanager.c entries_common.c entries_parse.c http_request.c json_common.c json_entries_parse.c json_oauth_parse.c oauth_manager.c perform_entries.c shared.c lib/jsmn/jsmn.c -o wallindle lib/curl_arm_32/lib/libcurl.a -lrt -DCURL_STATICLIB -Ilib/curl_arm_32/include -lm

$ ls -alh wallindle
-rwxr-xr-x 1 k users 193K 19 août  16:03 wallindle

$ file wallindle
wallindle: ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.3, for GNU/Linux 2.6.32, not stripped, with debug_info

Gathering informations

• Get your very own oAuth2 credentials follow instructions here

• Prepare configuration : Basically, concatening (as a single line) host, client_id, client_secret, username and password in a file.

# echo "https://wallabag.example.com 2_1xyggA5982e8oscs08os4ckckw00gcscs4g404sg44gg4gowoo 4u50vzwnrdwgo84c8wg8sgwskks888wskkc8o04o44kwg4080g root sV5G/aTjYRcNkSlTOsZuB78YG." > ./wallindle.cfg

Uploading to kindle

Do as you want : by command line, file manager or even ssh it doesn't matter. Storing both wallindle binary and configuration in the same folders as epub is a good option. Assuming that, your binary and config file are now stored in /mnt/base-us/documents/

Testing on kindle

$ ssh root@192.168.15.244


Welcome to Kindle!

root@192.168.15.244's password: 
#################################################
#  N O T I C E  *  N O T I C E  *  N O T I C E  # 
#################################################
Rootfs is mounted read-only. Invoke mntroot rw to
switch back to a writable rootfs.
#################################################

[root@kindle root]# cp /mnt/base-us/documents/wallindle* /tmp

[root@kindle root]# cd /tmp 

[root@kindle tmp]# ls -alh wallindle*
-rwxr-xr-x    1 root     root       192.8k Aug 19 14:34 wallindle
-rwxr-xr-x    1 root     root          168 Aug 19 14:34 wallindle.cfg

[root@kindle tmp]# ./wallindle
 token_count = 11
(...)
created_at= 2017-08-19T

MischiefManaged!

If you see "MischiefManaged!" then everything goes well :-). Otherwise you will see an error you can retrieve inside code source or by pinging me on twitter

In my case 7 files were downloaded :

[root@kindle tmp]# ls -alh /mnt/base-us/documents/wallabag/*mobi
-rwxr-xr-x    1 root     root       113.4k Aug 19 14:35 /mnt/base-us/documents/wallabag/0000010f.mobi
-rwxr-xr-x    1 root     root         4.5k Aug 19 14:35 /mnt/base-us/documents/wallabag/00000111.mobi
-rwxr-xr-x    1 root     root         1.5k Aug 19 14:35 /mnt/base-us/documents/wallabag/00000112.mobi
-rwxr-xr-x    1 root     root         3.6k Aug 19 14:35 /mnt/base-us/documents/wallabag/00000125.mobi
-rwxr-xr-x    1 root     root         3.3k Aug 19 14:35 /mnt/base-us/documents/wallabag/00000126.mobi
-rwxr-xr-x    1 root     root         9.4k Aug 19 14:35 /mnt/base-us/documents/wallabag/00000127.mobi
-rwxr-xr-x    1 root     root        16.0k Aug 19 14:35 /mnt/base-us/documents/wallabag/00000128.mobi

Let's the kindle fetching by itself

Now this is time for bad to really bad advices. Letting a non Amazon approved binary running by itself is a really bad idea. But :

• Even if kindle has other user accounts, only root can write on Document folders. In every case, wallindle must runs with root privilege, and it's a very bad news.

• None of the file stored on Document can be executed. No known workaround with the kernel 2.6.31 running in the Kindle.

• The Document directory is a fat32 filesystem, there is no rights management with it. Every files can be rw by owner and r by group and others.

Bad idea #1 : running as root a non protected binary

Keep in mind, it's a really bad idea : this create a very serious security issue

1. Storing wallindle and wallindle.cfg on Documents
2. Copy both from Documents to /tmp/
3. Launch wallindle ( /mnt/base-us/documents/wallabag directory in hardcoded )
4. crontab that

$ ssh root@192.168.15.244


Welcome to Kindle!

root@192.168.15.244's password: 
#################################################
#  N O T I C E  *  N O T I C E  *  N O T I C E  # 
#################################################
Rootfs is mounted read-only. Invoke mntroot rw to
switch back to a writable rootfs.
#################################################

[root@kindle root]# mntroot rw
system: I mntroot:def:Making root filesystem writeable
/dev/mmcblk0p1 on / type ext3 (rw,noatime,nodiratime)


[root@kindle root]# nano /etc/crontab/root 

Add this line :

00  */4 * * * (cd /mnt/us/documents/ && (./wallindle > wallindle.log))

Verify the new content

[root@kindle root]# cat /etc/crontab/root 
*/15 * * * * /usr/sbin/checkpmond
*/15 * * * * /usr/sbin/tinyrot
*/60 * * * * /usr/sbin/loginfo tmpfs
*/60 * * * * /usr/sbin/loginfo localVars
*/60 * * * * /usr/sbin/loginfo memusedump
*/15 * * * * /usr/sbin/loginfo powerdcheck

00  */4 * * * (cd /mnt/us/documents/ && (./wallindle > wallindle.log))

Remount / read only :

[root@kindle root]# mntroot ro
system: I mntroot:def:Making root filesystem read-only
/dev/mmcblk0p1 on / type ext3 (ro,noatime,nodiratime)

Restart cron agent :

[root@kindle root]# pkill crond && /usr/sbin/crond -c /etc/crontab/

Remember kids, this file will be run as root. Do you really want to transform your kindle in a piece of garbage ? I'm sure not.

Bad idea #2 : running as root a protected binary

Same as the first bad idea except you don't store wallindle in /mnt/base-us/documents/ but elsewhere on the rom of the kindle. In this case nobody can alter the binary but do you really want to alter the rom file structure list ?