Author: Mikael

Building the Darwin Streaming Server in Ubuntu

Me and a colleague tried building the Darwin Streaming server on Ubuntu Server 13.10 with the help of this guide [instructables.com].

It did not go as well as we were hoping due to build errors. After some troubleshooting (all credit goes to my colleague), it turned out that the linking of libraries was not done recursively. So even though the correct libraries was included in LDFLAGS it wouldn’t work.

With the following two changes, we got rid of the build errors:

$ cd lstoll*
$ find . -name "Makefile.*" -exec sed -i 's/-lQTFileExternalLib/-lQTFileExternalLib -lpthread/' {} \;
$ sed -i 's/-lQTFileLib/-lQTFileLib -ldl/' Makefile.POSIX

Installing Ubuntu on a Macbook Air (late 2010, 3.1)

I was craving running Linux on the desktop again, and the netbook I had lying around did not have proper support for the graphics card. This resulted in Unity not being that smooth, and the LVMPIPE mode really sucked.

So, I did something “drastic” and removed Mac OS X and installed Ubuntu 13.04 instead.

The Macbook Air (late 2010) has a Nvidia GeForce 320M graphics card and there is proprietary drivers for it. However, these does not work in EFI mode and by default Ubuntu is installed in EFI mode. I read some guides on how to convert the GPT partition table before installing, men turned out that it was still a GPT partition table after the installation finished. Therefor I had to convert it after the installation, following these [ubuntu.com] instructions. After converting to legacy BIOS, I installed the proprietary Nvidia drivers.

Other than the official tips in the Ubuntu community documentation [ubuntu.com], I also made the following changes to get the keyboard to work as similar as in Mac OS X (Settings, Keyboard Layout, Options):

  • Win keys (and the usual ctrl): To use cmd + c/v to copy, paste etc.
  • Key to choose 3rd level, Any Alt key: to get /, | and \ to work like in Mac OS X

After installing the Linux version of Spotify, I wanted the multimedia buttons on the keyboard to control Spotify. I found the following information [mabishu.com] that Spotify had built in support for dbus, så it was just a matter of writing a small script:

#!/usr/bin/env bash
dbus-send --print-reply --dest=org.mpris.MediaPlayer2.spotify /org/mpris/MediaPlayer2 org.mpris.MediaPlayer2.Player.$1

Then you’d have to create keyboard shortcuts for Audio Play (argument “PlayPause”), Audio next (argument “Next”) and Audio previous (argument “Previous”) which would execute the script.

I really hate Windows (Unable to start Group Policy Client)

I’m sitting and installing updates on my girlfriends Windows 7 laptop. After the installation is finished and the computer restarts the first time; enter blue screen of death. Fair enough, it is what windows does. I restart it a second time and it boots without problem, except that it is not possible to login with any user that does not have administrator privileges. I spend the whole evening trying to find a solution for the problem, without any initial success.

Gave it another shot the day after, searching for solutions, and I actually found one! I’d say it looks a bit magical, but it works. However, it says a lot about windows and specially the windows register!

  1. Open regedit
  2. Find HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services. This path must contain a key with the name gpsvc, in my case it was intact, but double check that it truly exist. If it does not exist, you might get some guidance here [batcmd.com]
  3. HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Svchost, this is the most important path since it must contain the keys and values in step 2.
  4. Make sure that the key above has a multi-string key that is named GPSvcGroup where the value is GPSvc
  5. Make sure that the key in step 3 has a sub-key named GPSvcGroup
  6. This key should have two DWORD (32-bit) values:
  • AuthenticationCapabilities with the value 0x00003020 (12320 decimal)
  • CoInitializeSecurityParam with the value 1

When above steps are finished, just reboot the computer and hopefully you’ll be able to login with non-administrator users again.

A big thank you to SQL-ER [microsoft.com] on the Windows 7 technet forum [microsoft.com] that provided the fix.

Automagically build load modules when updating the kernel

I bought a new wireless network card to my parents, and it turned out that there wasn’t support in the generic Ubuntu kernel for it. The last month they haven’t been able to use their computer since the card stopped working after updating the kernel, and hence missing the custom built load module.

After rebuilding the load module I was following the output when installing about 200 updates and saw that after updating the kernel there were some scripts from /etc/kernel/postinst.d running.

I then realized that it should be possible to solve the problem by adding a custom script that would rebuild the load module when updating the kernel.

Step 1 was to create a script in both /etc/kernel/postinst.d and /etc/kernel/header_postinst.d that I named build_wifi_driver:

#!/bin/bash
# We're passed the version of the kernel being installed
inst_kern=$1

cd /root/DPO_RT3070_LinuxSTA_V2.3.0.4_20100604/
make KERNEL_VERSION=$inst_kern
make KERNEL_VERSION=$inst_kern install

The second problem was that the Makefiles for the load module had to be updated to use $(KERNEL_VERSION) instead of $(shell uname -r). I had to update three different Makefiles:

DPO_RT3070_LinuxSTA_V2.3.0.4_20100604/Makefile:

--- DPO_RT3070_LinuxSTA_V2.3.0.4_20100604/Makefile    2009-12-28 13:38:34.000000000 +0100
+++ DPO_RT3070_LinuxSTA_V2.3.0.4_20100604.new/Makefile    2011-01-05 19:17:14.000000000 +0100
@@ -117,11 +117,14 @@
endif

ifeq ($(PLATFORM),PC)
+ifndef KERNEL_VERSION
+    KERNEL_VERSION := $(shell uname -r)
+endif
# Linux 2.6
-LINUX_SRC = /lib/modules/$(shell uname -r)/build
+LINUX_SRC = /lib/modules/$(KERNEL_VERSION)/build
# Linux 2.4 Change to your local setting
#LINUX_SRC = /usr/src/linux-2.4
-LINUX_SRC_MODULE = /lib/modules/$(shell uname -r)/kernel/drivers/net/wireless/
+LINUX_SRC_MODULE = /lib/modules/$(KERNEL_VERSION)/kernel/drivers/net/wireless/
CROSS_COMPILE =
endif

@@ -234,7 +237,7 @@
endif

cp -f os/linux/Makefile.4 $(RT28xx_DIR)/os/linux/Makefile
-    $(MAKE) -C $(RT28xx_DIR)/os/linux/
+    $(MAKE) KERNEL_VERSION=$(KERNEL_VERSION)-C $(RT28xx_DIR)/os/linux/

ifeq ($(OSABL),YES)
cp -f os/linux/Makefile.4.netif $(RT28xx_DIR)/os/linux/Makefile
@@ -279,7 +282,7 @@
ifeq ($(PLATFORM),FREESCALE8377)
$(MAKE) ARCH=powerpc CROSS_COMPILE=$(CROSS_COMPILE) -C  $(LINUX_SRC) SUBDIRS=$(RT28xx_DIR)/os/linux modules
else
-    $(MAKE) -C $(LINUX_SRC) SUBDIRS=$(RT28xx_DIR)/os/linux modules
+    $(MAKE) -C $(LINUX_SRC) SUBDIRS=$(RT28xx_DIR)/os/linux KERNEL_VERSION=$(KERNEL_VERSION) modules
endif
endif

DPO_RT3070_LinuxSTA_V2.3.0.4_20100604/os/linux/Makefile.4

--- DPO_RT3070_LinuxSTA_V2.3.0.4_20100604/os/linux/Makefile.4    2009-12-30 02:12:06.000000000 +0100
+++ DPO_RT3070_LinuxSTA_V2.3.0.4_20100604.new/os/linux/Makefile.4    2011-01-05 19:01:56.000000000 +0100
@@ -13,6 +13,9 @@

OBJ := $(MOD_NAME).o

+ifndef KERNEL_VERSION
+KERNEL_VERSION := $(shell uname -r)
+endif

#ifdef CONFIG_STA_SUPPORT
RT28XX_STA_OBJ := \
@@ -200,9 +203,9 @@
cp $(RT28xx_DIR)/$(DAT_FILE_NAME) $(DAT_PATH)/.
install -d $(LINUX_SRC_MODULE)
install -m 644 -c $(addsuffix .o,$(MOD_NAME)) $(LINUX_SRC_MODULE)
-    /sbin/depmod -a ${shell uname -r}
+    /sbin/depmod -a $(KERNEL_VERSION)

uninstall:
#    rm -rf $(DAT_PATH)
rm -rf $(addprefix $(LINUX_SRC_MODULE),$(addsuffix .o,$(MOD_NAME)))
-    /sbin/depmod -a ${shell uname -r}
+    /sbin/depmod -a $(KERNEL_VERSION)

DPO_RT3070_LinuxSTA_V2.3.0.4_20100604/os/linux/Makefile.6

--- DPO_RT3070_LinuxSTA_V2.3.0.4_20100604/os/linux/Makefile.6    2009-12-30 02:12:13.000000000 +0100
+++ DPO_RT3070_LinuxSTA_V2.3.0.4_20100604.new/os/linux/Makefile.6    2011-01-05 19:02:29.000000000 +0100
@@ -12,6 +12,10 @@

obj-m := $(MOD_NAME).o

+ifndef KERNEL_VERSION
+KERNEL_VERSION := $(shell uname -r)
+endif
+

#ifdef CONFIG_STA_SUPPORT
rt$(CHIPSET)sta-objs := \
@@ -198,9 +202,9 @@
cp $(RT28xx_DIR)/$(DAT_FILE_NAME) $(DAT_PATH)/.
install -d $(LINUX_SRC_MODULE)
install -m 644 -c $(addsuffix .ko,$(MOD_NAME)) $(LINUX_SRC_MODULE)
-    /sbin/depmod -a ${shell uname -r}
+    /sbin/depmod -a $(KERNEL_VERSION)

uninstall:
#    rm -rf $(DAT_PATH)
rm -rf $(addprefix $(LINUX_SRC_MODULE),$(addsuffix .ko,$(MOD_NAME)))
-    /sbin/depmod -a ${shell uname -r}
+    /sbin/depmod -a $(KERNEL_VERSION)

I’m no expert when it comes to Makefiles, but these changes solved the issue and the load module now builds automagically every time the kernel was updated.

Öppna Finders nuvarande plats i Terminal

En sak som jag tänkt på mycket men aldrig kommit mig för att undersöka är om det fanns något smidigt sätt att öppna katalogen man navigerat till via Finder i Terminal. En liten snabb googlesökning tog mig, givetvis, till macosxhints.com: A script to open current Finder folder in the Terminal.

Öppna “AppleScript Editor” (finns under Applications, Utilities), kopiera kodsnutten från ovanstående länk och spara. Det är dock väldigt viktigt att spara det som en applikation och inte ett script.

När detta är gjort är det bara att dra filen till Finderns verktygsrad. I och med detta får den dock standard ikonen, vilket inte är särkilt snyggt. Gå till Applications, Utilities och högerklicka på “Terminal”, välj “Get Info”. Högerklicka på AppleScript filen (som sparats som en applikation) och välj “Get Info”. Klicka på ikonen för “Terminal” och tryck cmd+c (kopiera), klicka på ikonen för AppleScriptet och tryck cmd+v (klistra in). Detta gör att ditt AppleScript får samma ikon som “Terminal”.