WebOS Internals - User contributions [en]

User talk:Wrea

2011-12-28T01:17:54Z

Wrea: Blanked the page

Avahi

2011-12-28T01:07:02Z

Wrea: Minor edits, referencing avahi being in repo

=Avahi=
[http://avahi.org Avahi] is a Linux service for providing multicast-DNS/DNS-SD (also known as [http://en.wikipedia.org/wiki/Bonjour_%28software%29 Bonjour] or mDNS/DNS-SD). Avahi allows for simple service discovery and advertisement on a local network and provides name resolution for all hosts running a mDNS/DNS-SD service.

Using Avahi allows for easy SSH access, among other things, over a local wireless network. Once installed and started, users can ssh to their device using their mDNS assigned hostname.

==Avahi Installation==

For 2.x and 3.x devices, avahi can be found in the alpha repo, any other devices install via ipkg as follows:

First, use novacom to access the Pre and install the Avahi ipkg.

$> sudo /opt/bin/ipkg-opt install avahi

Avahi seems to want to run as a user named "avahi". To create the user, run the following command:

$> adduser -h /opt/var/run/avahi avahi

Avahi currently attempts to access a different dbus system socket than the one provided by the Pre's dbus, it is possible to start Avahi with dbus support by creating a symbolic link from palm dbus directory to the /opt dbus directory and starting avahi daemon with root privileges. According to the Avahi website, however running avahi-daemon with root privileges is not recommended.

The following command will create a symbolic link to /opt dbus directory to palm dbus directory:

ln -s /var/run/dbus /opt/var/run/dbus

if preferred avahi can be be ran without dbus support by editing <tt>/opt/etc/avahi/avahi-daemon.conf</tt> and make the following change:

Replace this line:
#enable-dbus=yes

With this line:
enable-dbus=no

However, this does not allow the use of avahi commands such as avahi-browse, avahi-publish etc...

At this point, the Avahi daemon can be started with root privileges and dbus support with the following command:

$> /opt/sbin/avahi-daemon --no-drop-root

If you disabled dbus support however it is recommended to run Avahi daemon without root privileges using the following command:

$> /opt/sbin/avahi-daemon

If you would like Avahi to start up at boot, create the following two files:

'''/opt/etc/init.d/S60avahi'''
#!/bin/sh

[ -e /opt/etc/default/avahi ] && . /opt/etc/default/avahi

if [ "$AVAHI_ENABLE" = "no" ]; then
exit
fi

if [ -n "`pidof /opt/sbin/avahi-daemon`" ]; then
killall /opt/sbin/avahi 2>/dev/null
fi

/opt/sbin/avahi-daemon -D

'''/opt/etc/default/avahi'''
AVAHI_ENABLE=yes

Make sure you set the startup script to executable:

$> chmod 755 /opt/etc/init.d/S60avahi

Alternatively, you can create an upstart script at '''/etc/event.d/avahi''':

start on started PmConnectionManager

console output

exec /opt/sbin/avahi-daemon -D
respawn

NOTE: This script is not being stored in the /opt directory. You may have to replace it after an update, and it may cause problems with your Pre.

==Connecting via SSH using mDNS==

mDNS uses the system's hostname and appends it to the <tt>local.</tt> domain. Using the Pre's default <tt>palm-webos-device</tt> hostname, the following command would be used to SSH to your Pre on port 222:

$> ssh -P 222 palm-webos-device.local.

If you are using an OpenSSH key to connect:

$> ssh -i /path/to/ssh/key palm-webos-device.local.

'''Note: The system that you are connecting from MUST have a mDNS service also running, else the hostname will not resolve'''

==Current Issues on the Pre==

* The ipkg binary of Avahi attempts to find the dbus socket at <tt>/opt/var/run/dbus/system_bus_socket</tt>, but the Pre's dbus socket is at <tt>/var/run/dbus/system_bus_socket</tt>. I have detailed a solution by running Avahi with root privileges however an approach which allow it to run after dropping root privileges is preferred.
* The avahi-daemon seems to have issues keeping the mDNS name resolution running for more than a few minutes. I don't know if this is a power management issue or something else at this point.

User talk:Wrea

2011-12-26T21:30:00Z

Wrea: Reworking of avahi page for when avahi is in the wosi feed

=Avahi=
[http://avahi.org Avahi] is a Linux service for providing multicast-DNS/DNS-SD (also known as [http://en.wikipedia.org/wiki/Bonjour_%28software%29 Bonjour] or mDNS/DNS-SD). Avahi allows for simple service discovery and advertisement on a local network and provides name resolution for all hosts running a mDNS/DNS-SD service.

Using Avahi allows for easy SSH access, among other things, over a local wireless network. Once installed and started, users can ssh to their device using their mDNS assigned hostname.

==Avahi Installation==
For 2.x and 3.x devices, avahi can be found in the alpha repo, any other devices install via ipkg as follows:

First, use novacom to access the Pre and install the Avahi ipkg.

$> sudo /opt/bin/ipkg-opt install avahi

Avahi seems to want to run as a user named "avahi". To create the user, run the following command:

$> adduser -h /opt/var/run/avahi avahi

Avahi currently attempts to access a different dbus system socket than the one provided by the Pre's dbus, it is possible to start Avahi with dbus support by creating a symbolic link from palm dbus directory to the /opt dbus directory and starting avahi daemon with root privileges. According to the Avahi website, however running avahi-daemon with root privileges is not recommended.

The following command will create a symbolic link to /opt dbus directory to palm dbus directory:

ln -s /var/run/dbus /opt/var/run/dbus

if preferred avahi can be be ran without dbus support by editing <tt>/opt/etc/avahi/avahi-daemon.conf</tt> and make the following change:

Replace this line:
#enable-dbus=yes

With this line:
enable-dbus=no

However, this does not allow the use of avahi commands such as avahi-browse, avahi-publish etc...

At this point, the Avahi daemon can be started with root privileges and dbus support with the following command:

$> /opt/sbin/avahi-daemon --no-drop-root

If you disabled dbus support however it is recommended to run Avahi daemon without root privileges using the following command:

$> /opt/sbin/avahi-daemon

If you would like Avahi to start up at boot, create the following two files:

'''/opt/etc/init.d/S60avahi'''
#!/bin/sh

[ -e /opt/etc/default/avahi ] && . /opt/etc/default/avahi

if [ "$AVAHI_ENABLE" = "no" ]; then
exit
fi

if [ -n "`pidof /opt/sbin/avahi-daemon`" ]; then
killall /opt/sbin/avahi 2>/dev/null
fi

/opt/sbin/avahi-daemon -D

'''/opt/etc/default/avahi'''
AVAHI_ENABLE=yes

Make sure you set the startup script to executable:

$> chmod 755 /opt/etc/init.d/S60avahi

Alternatively, you can create an upstart script at '''/etc/event.d/avahi''':

start on started PmConnectionManager

console output

exec /opt/sbin/avahi-daemon -D
respawn

NOTE: This script is not being stored in the /opt directory. You may have to replace it after an update, and it may cause problems with your Pre.

==Connecting via SSH using mDNS==

mDNS uses the system's hostname and appends it to the <tt>local.</tt> domain. Using the Pre's default <tt>palm-webos-device</tt> hostname, the following command would be used to SSH to your Pre on port 222:

$> ssh -P 222 palm-webos-device.local.

If you are using an OpenSSH key to connect:

$> ssh -i /path/to/ssh/key palm-webos-device.local.

'''Note: The system that you are connecting from MUST have a mDNS service also running, else the hostname will not resolve'''

==Current Issues on the Pre==

* The ipkg binary of Avahi attempts to find the dbus socket at <tt>/opt/var/run/dbus/system_bus_socket</tt>, but the Pre's dbus socket is at <tt>/var/run/dbus/system_bus_socket</tt>. I have detailed a solution by running Avahi with root privileges however an approach which allow it to run after dropping root privileges is preferred.
* The avahi-daemon seems to have issues keeping the mDNS name resolution running for more than a few minutes. I don't know if this is a power management issue or something else at this point.

USB Host Mode

2011-10-01T02:43:48Z

Wrea: Detail of an error and a workaround

External vbus power is easy:

Connect your type A (with ID-pin shorted) microUSB to USB cable into webOS. Plug the data leg of USB-Y cable (usually found with 2.5" external HDD enclosures and such) into this cable. Plug the root of the Y cable into a hub or whatever device you plan to use.
Plug the "power" leg of the Y cable into some powered usb socket be it a powered hub, a PC or whatever.
Enjoy your usb device.

Example of cable that will work: http://www.ebay.com/itm/High-Quality-micro-USB-USB-Female-Cable-USB-OTG-N900-/170687828639?pt=PDA_Accessories&hash=item27bdc9929f
Search for OTG cable on eBay and thee are plenty.

The USB-ID should be 1-1

Internal VBUS:

TBD.

If you get a error like this in dmesg:

<source lang="text">
usb 1-1: rejected 1 configuration due to insufficient available bus power
</source>
This command got me past this error:

<source lang="text">
echo 1 > /sys/bus/usb/devices/1-1/bConfigurationValue
</source>
This worked for me and hopefully it can be of use to someone