Category: Technology

Weird JavaScript Date Bug

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Today I found a very weird bug in JavaScript – The date function. I never expected to see a bug in the standard JavaScript implementation. Here is my code. It does nothing more than adding 21 days on the reference date:

var referenceDateObject	= new Date(2011, 9, 10);
var deliveryDateObj 	= new Date(referenceDateObject.getTime() + 24 * 60 * 60 * 1000 * 21);
var deliveryDateMonth	= parseInt(deliveryDateObj.getUTCMonth());
var deliveryDateString	= deliveryDateObj.getUTCFullYear() + '-' + deliveryDateMonth + '-' +  deliveryDateObj.getUTCDate();
alert(deliveryDateString);

Given a reference date of September 10, 2011, I expect the date should be October 1, 2011. However, it ends up returning me September 31, which doesn’t exist!

I test that on Firefox and Google Chrome, both give the same problem. A quick fix will be moving the date calculation to the server side.

P.S. MySQL date function automatically convert 9/31 to 10/1, so the data on the server looks fine.

Update – That’s my fault. The Date object treats the month from 0-11 instead of 1-12. Here is a corrected version:

var referenceDateObject	= new Date(2011, 8, 10);   //That's September 10, 2011, not August 10.
var deliveryDateObj 	= new Date(referenceDateObject.getTime() + 24 * 60 * 60 * 1000 * 21);
var deliveryDateMonth	= parseInt(deliveryDateObj.getUTCMonth()) + 1;
var deliveryDateString	= deliveryDateObj.getUTCFullYear() + '-' + deliveryDateMonth + '-' +  deliveryDateObj.getUTCDate();
alert(deliveryDateString);

That will do the trick.

–Derrick

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Apache won’t start after upgrading to 2.2.21 in FreeBSD 8.2

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Apache 2.2.21 was rolled out today. Since it has some security fixes, I decide to put a new version on my server farm. I didn’t know that it becomes a small headache today morning.

The upgrade was running smooth, no error messages, no complaints, until I restart the Apache server manually

sudo apachectl restart

And guess what, my website didn’t show up on the browser. Instead, I saw the following picture on my browser:

That was not fun at all. So I decided to investigate what was wrong to the upgrade.

sudo tail /var/log/httpd-error.log

And I found something interesting:

httpd: Syntax error on line 100 of /usr/local/etc/apache22/httpd.conf:
Cannot load /usr/local/libexec/apache22/mod_negotiation.so into server:
/usr/local/libexec/apache22/mod_negotiation.so: Undefined symbol "ap_set_accept_ranges"

Therefore, I edited my Apache configuration and commented out that module:

#LoadModule negotiation_module libexec/apache22/mod_negotiation.so

Saved the file and restarted the server again. Now the problem is gone!

sudo apachectl stop
sudo apachectl start

When I tried to visited the website again, I found that the speed is bit slow. I think it has something to do with the mod_negotiation.so. I decided to rebuild the Apache.

cd /usr/ports/www/apache22
sudo make config

Make sure that the Negotiation: Enable mod_negotiation is checked.

sudo make

Running sudo make is enough. You don’t need to re-run sudo make install or sudo make reinstall.

This will rebuild the necessary libraries including the missing mod_negotiation.so.

Go back to the configuration file and enable the module again:

LoadModule negotiation_module libexec/apache22/mod_negotiation.so

Restart the server:

sudo apachectl restart

That’s it! Happy Apaching!

–Derrick

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What OS is good for SPARC64?

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Recently, I received a SPARC64 machine (Sun Blade 100) as a gift. If you are not sure what is SPARC64, it is a CPU primary manufactured by Sun/Oracle. It is quite different than Intel x86 / AMD 64, so anything that is compiled to run on these two platforms will not work on SPARC64. Besides, Sun/Oracle is currently shifting toward to Intel now, which means the SPARC64 will become less popular in the long run. Since I don’t want to let my Sun Blade becomes a paper-weight / foot stool, I decide to explore some options on what I can do with it.

Notice that this list only includes some popular operating systems I’ve tested only. I am pretty sure that there are lots of more choices available.

If you don’t want to go through the entire list, here are some quick recommendations:
Good: FreeBSD, NetBSD, OpenBSD, OpenSolaris
Okay: Debian
Avoid: Fedora, Ubuntu

The following operating system are listed in alphabetically:

Debian Linux

Recommendation: Yes if you don’t care about the performance
Support Status: Active
Comment: Although Debian provides a 64-bit version, the applications are run in 32-bit mode (Source). It can not only cause performance issue because the application does not utilize the full power of the CPU. For example, a 32-bit application can only handle unsigned integer from 0 to 2^31-1 (2147483647).

Fedora Linux

Recommendation: No
Support Status: Seems Discontinued.
Comment: As of today, the latest version of Fedora is 15. However, the latest version for SPARC is 12/13. Seems like the support in this architecture is inactive.
Source: Architectures/SPARC

FreeBSD

Recommendation: Yes
Support Status: Active
Comment: The command freebsd-update is not supported in SPARC64. In the other words, you have to rebuild the kernel from scratch in order to upgrade the system to a newer version

NetBSD

Recommendation: Yes
Support Status: Active
Download: Here

OpenBSD

Recommendation: Yes
Support Status: Active

OpenIndiana

Recommendation: Yes
Support Status: Active

OpenSolaris

Recommendation: No
Support Status: Discontinued

Ubuntu Linux

Recommendation: No
Support Status: Inactive
Comment: Ubuntu already dropped support to SPARC64. Forget about it.
Source: Ubuntu drops support for ia64 and sparc

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cups-client-1.4.8 is marked as broken: gnutls does not support threads yet; disable the GNUTLS.

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I saw this message twice on two machines on two different days, end up using the same way to fix it.

Case 1: Samba

My Samba was down today, so I tried to start it manually:

/usr/local/etc/rc.d/samba start

And I got the following error message:

Removing stale Samba tdb files:  done
nmbd already running? (pid=1074).
Starting smbd.
/libexec/ld-elf.so.1: Shared object "libcups.so.2" not found, required by "smbd"
/usr/local/etc/rc.d/samba: WARNING: failed to start smbd

Initially, I thought the problem was about missing the file. So I did a search and soft-link it:

find / -name "libcups.so*"

Surprisingly, there is no such file in my system. I think I don’t have this file. So I tried to compile the Samba again:

cd /usr/ports/net/samba35
sudo make

and I got the following message:

===>  cups-client-1.4.8 is marked as broken: gnutls does not support threads yet disable the GNUTLS.
*** Error code 1

Stop in /usr/ports/print/cups-client.

Case 2: Upgrading Port

When I upgraded my FreeBSD system via portmaster, I found the following messages:

portmaster -Da

===>  cups-client-1.4.8 is marked as broken: gnutls does not support threads yet disable the GNUTLS.
*** Error code 1

Stop in /usr/ports/print/cups-client.

Initially, I tried to by-pass upgrading the cups-client using:

portmaster -Dai

However, it is very annoying to do it everyday, therefore I decide to solve this problem.

Solution

From the error message, it seems that the problem is caused by the additional option in cups-client: GNUTLS. So I decide to disable this option in the GNUTLS:

cd /usr/ports/print/cups-client
sudo make config

Uncheck “GNUTLS: Build with GNUTLS instead of OpenSSL”

and try to compile it again:

sudo make

Now re-run the portmaster:

sudo portmaster -Da

The problem is gone.

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How to clean up the dmesg message

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Recently, I found that my dmesg log are filled of junk. Or I should say it contains lots of errors and complains that I already fix. However, I don’t want to reboot the machine to get rid of these error messages. How can I do it? The solution is very simple.

For FreeBSD and other BSD members, run the following:

sudo sysctl kern.msgbuf_clear=1

For Fedora / Ubuntu Linux, run the following instead:

sudo dmesg -c

Easy?

–Derrick

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PHP Warning: PHP Startup: Unable to load dynamic library ‘/usr/local/lib/php/20090626/tokyo_tyrant.so’ – /usr/local/lib/php/20090626/tokyo_tyrant.so: Undefined symbol “ps_globals” in Unknown on line 0

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Every time I upgrade the PHP and related extensions, I always run into the same problem with some PHP-PECL modules. Recently with the new release of PHP 5.3.7, there is no exception for the trouble. So what kind of trouble I have today? The Tokyo Tyrant (The middleman between my program and Tokyo Cabinet).

#php -v

PHP Warning:  PHP Startup: Unable to load dynamic library '/usr/local/lib/php/20090626/tokyo_tyrant.so' - /usr/local/lib/php/20090626/tokyo_tyrant.so: Undefined symbol "ps_globals" in Unknown on line 0

This problem was caused by a version mis-match. PHP is running at a later version, which the Tokyo Tyrant extension is running at an earlier version. To solve this computer problem, all you need is to re-install the PHP-Tokyo-Tyrant extension, i.e.,

cd /usr/ports/databases/pecl-tokyo_tyrant
suod make deinstall clean
sudo make install

And later, you may or may not get the following error message:

...
cc -shared  .libs/tokyo_tyrant.o .libs/tokyo_tyrant_funcs.o .libs/connection.o .libs/session_funcs.o .libs/server_pool.o .libs/failover.o .libs/session.o  -Wl,--rpath -Wl,/usr/local/lib -Wl,--rpath -Wl,/usr/local/lib -L/usr/local/lib -ltokyotyrant -llua -ltokyocabinet /usr/local/lib/liblzo2.so -llzma -lbz2 -lz -lrt -lm  -Wl,-soname -Wl,tokyo_tyrant.so -o ./.libs/tokyo_tyrant.so
/usr/bin/ld: cannot find -llua
*** Error code 1

Stop in /usr/ports/databases/pecl-tokyo_tyrant/work/tokyo_tyrant-0.6.0.
*** Error code 1

Stop in /usr/ports/databases/pecl-tokyo_tyrant.

The problem is related to Lua. By default, the extension enable the Lua option, which I have a hard time to make it run properly on FreeBSD box. Since my website does not use the Lua with Tokyo Cabinet, I simply disable it:

sudo nano /usr/ports/databases/pecl-tokyo_tyrant/work/tokyo_tyrant-0.6.0/Make

Look for the keyword: lua
And you will find something like the following:

TOKYO_TYRANT_SHARED_LIBADD = -R/usr/local/lib -L/usr/local/lib -R/usr/local/lib -L/usr/local/lib -ltokyotyrant -llua -ltokyocabinet -lbz2 -lz -lrt -lm -ltokyocabinet -llzo2 -llzma -lbz2 -lz -lrt -lm

Delete the option: “-llua”, i.e.,

TOKYO_TYRANT_SHARED_LIBADD = -R/usr/local/lib -L/usr/local/lib -R/usr/local/lib -L/usr/local/lib -ltokyotyrant -ltokyocabinet -lbz2 -lz -lrt -lm -ltokyocabinet -llzo2 -llzma -lbz2 -lz -lrt -lm

and re-start the installation:

cd /usr/ports/databases/pecl-tokyo_tyrant
sudo make install clean

Now re-run the php, and you may see the following error:

#php -v

PHP Warning:  PHP Startup: Unable to load dynamic library '/usr/local/lib/php/20090626/tokyo_tyrant.so' - /usr/local/lib/php/20090626/tokyo_tyrant.so: Undefined symbol "ps_globals" in Unknown on line 0
Segmentation fault: 11

That’s because the Tokyo Tyrant module is placed at a wrong position in the PHP extension file. Edit the file:

sudo nano /usr/local/etc/php/extensions.ini

and move the following code to the END of the file (Yes, order does matter):

extension=tokyo_tyrant.so

And re-check your php:

#php -v

PHP 5.3.7 with Suhosin-Patch (cli) (built: Aug 23 2011 10:33:12)
Copyright (c) 1997-2011 The PHP Group
Zend Engine v2.3.0, Copyright (c) 1998-2011 Zend Technologies

Now everything is all set.

Unfortunately, you pretty much need to do the same thing every time when upgrading your PHP on FreeBSD box.

–Derrick

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HighPoint RocketRAID 2640X4SGL Beeping

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I noticed some beeping sound coming from my server today. After I opened the server case, I found that the problem came from my newly install HighPoint RocketRAID card. During the beep, the server could not operate normally. First, the system dumped some error messages, and followed by core dump, and the computer ended up rebooting by itself. After the system was restarted, during the first few seconds, the system was doing fine. After waiting for couple minutes, the error happened again. So I know that it was not some random error, and it was repeatable.

Here are my step-by-step guide on how to solve this problem:

Beeping doesn’t mean defective

After reading the manual, I found that beeping is part of the monitoring process. If the card detects any failure in the RAID system, it will start beeping. If you have any doubt, try to run the card on a different machine. That’s the best way to verify whether the card is defective or not.

Did you make any change to the system recently

Making a system stable is not easy, because you don’t know whether the hardware are conflicting with each other, or the newly installed module will cause the system unstable or not. For example, I found that the beeping happened after I enabled the Linux Emulation module in FreeBSD. After I turned that off, things are working fine.

Are the cables securely attached?

SATA harddrive pretty much is the standard today. It is fast and doesn’t take up lots of space. However, unlike the old IDE cable, it is very easy to get loosen. After I unplugged all the attached SATA cables from the RAID card, and put them back afterward, the problem seemed gone.

Flash the firmware

Although this is not likely, but the problem can sometimes caused by an out-dated firmware. (I have experience a similar thing on my motherboard before). Try to flash the card with the latest firmware.

If none of these methods work for you, sounds like your card is defective.

–Derrick

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How to install HighPoint RocketRAID 2640X4SGL on FreeBSD 8.X

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This tutorial is for FreeBSD 8. If you are looking for the driver for FreeBSD 9, you can forget about it. According to HighPoint, there are no plans to update the RocketRaid 26XX driver to FreeBSD 9. Since it is a binary driver, there are very limited things we can do. FYI, here is the reply from their support team:

New Priority: Medium

Status: Active -> Awaiting Customer Action

Dear customer there are no plans to update the RocketRAID driver to support FreeBSD 9.0.

Note: Our RocketRAID 27xx series controllers have native support in FreeBSD 9.0.

Regards

HighPoint Support Team

I will never purchase any product from this HighPoint.

Recently I decide to upgrade my file server. I decide to get a PCI-Express SATA controller, and attach my hard-drives to it. After researching some cards, I finally decide to buy this one:

HighPoint RocketRAID 2640X4SGL

What it differentiates with other similar cards is the number of PCI-express channel. It comes with 4 channels while the other cards only carry one. In the other words, it will make transfer speed higher.

Anyway, long story short. FreeBSD does not recognize this card by default. You need to install a driver to support it. Unfortunately, the driver is version specific, and the driver on the web only supports up to FreeBSD 7. I have two choices – Switch to the legacy Microsoft Windows / Linux, or downgrade to FreeBSD 7.0. One way or the other, I need to say Goodbye to ZFS.

After some searches and hacks, finally I found the hidden driver. Here you are: Driver For FreeBSD 8.X

1. Extract the driver

tar -zxvf rr26xx-bsd-8.0-v1.2.tgz

2. Copy the driver (64-bit)

cp rr26xx-8.0-amd64.ko /boot/kernel/rr26xx.ko

3. Add the following in /boot/defaults/loader.conf

rr26xx_load="YES"

4. Reboot

reboot

4. After the reboot is done, you can see the hard-drives (/dev/da*) by running the following commands:

dmesg | grep da

That’s it! Have fun.

–Derrick

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Upgrade Fedora Linux Using Command Line

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Recently, I decide to upgrade all of the Fedora Linux servers. As of today, the latest version is Fedora 15. As for my servers, they are in between Fedora 11 and 14. In the other words, I will need to upgrade some machine from 11 all the way to 15.

There are several ways to upgrade the Fedora system. You can either do it through the GUI (With physical access to the machine), GUI (Though VNC), or command line. I prefer the last option because I have limited number of monitors and input devices.

I haven’t tried upgrading Fedora through command line before. The experience is very different comparing to FreeBSD. So I am going to list out what I have done step by step:

1. Backup your data. Although I haven’t experienced any data loss during the upgrade. It is always a good idea to have a backup first.

2. Make sure that your system is up to date with your current version:

sudo yum update

3. Install preupgrade:

sudo yum install preupgrade -y

4. Run the preupgrade:

sudo preupgrade-cli "Fedora 15 (Lovelock)"

It will download the packages from the server. Depending on your system settings, my system downloaded around 1500 packages, which took about 10 to 20 minutes. After that, it will prompt to reboot the machine.

5. This step is optional. Connect your monitor, keyboard and mouse to the machine.

6. Reboot your server

sudo reboot

7. Now the system will boot into the upgrade interface and perform the upgrade. Notice that this step can easily take 2 to 3 hours (My machine: Q6700 Quad Core, Ram: 8GB). During the upgrade, you cannot remotely access the computer. If you try to connect a monitor / keyboard / mouse, it may give no response. Just be patient and wait. It is not a good idea to reboot your machine at this stage.

8. After waiting for nearly 2.5 hour (2 hours to unpack and install the package, half hour to clean up the package), the machine finally reboots.

9. You should be able to remotely access this machine from SSH. Run the following command to determine your Fedora version:

cat /etc/redhat-release && uname -a

10. Run the following commands to clean up the system:

sudo yum update
sudo package-cleanup --orphans
sudo updatedb
sudo yum repolist 
sudo yum distro-sync

10. Enjoy your new system.

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How to remove .DS_Store and .AppleDouble

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If you’ve shared your Windows / Unix drives with Mac OS X before, you may notice that Mac OS X will leave some footprints on your shared folders, such as .DS_Store and .AppleDouble. These files and directories are pretty annoying because they showed up in almost every single directory you accessed from the OS X.

There are two ways to solve this computer problem:

  1. Ask Apple to stop generating the .DS_Store
  2. Delete .DS_Store by yourself
  3. Set the shared folder to read-only

Apple had a tutorial on how to stop generating the .DS_Store (See here for details), however this solution requires you to run the command on every single account on every mac.

…If you want to prevent .DS_Store file creation for other users on the same computer, log in to each user account and perform the steps above…

In the other words, you will need to run the command for (# of user on each mac) x (# of mac) times!

For example, if you have 5 users on each mac, and you have 4 macs. You will need to run the command for 5 x 4 = 20 times! Also, I’ve tried this method before and the problem seemed coming back after the upgrading the system (e.g., from OS X 10.7 to 10.7.1). Therefore I decide to go with the second solution: Delete .DS_Store by myself.

How to delete .DS_Store and .AppleDouble automatically

Depending on what operating system the shared drives locate, there are two different ways to solve this problem, and they are very similar.

Situation 1: The shared folder is on Windows

If the shared folder located on a Windows machine, you may want to delete .DS_Store and .AppleDouble from the OS X. First, go to Terminal first:

Create a script

nano clean.sh

Now you are in a text editor. Copy and paste the following into the editor:

find . -name ".DS_Store"        -exec rm -Rf {} \;
find . -name ".apdisk"          -exec rm -Rf {} \;
find . -name ".AppleDouble"     -exec rm -Rf {} \;
find . -name ".AppleDB"         -exec rm -Rf {} \;
find . -name "afpd.core"        -exec rm -Rf {} \;
find . -name ".TemporaryItems"  -exec rm -Rf {} \;
find . -name "__MACOSX"         -exec rm -Rf {} \;
find . -name "._*"              -exec rm -Rf {} \;

Save the file. Don’t forget that we need to make it executable.

chmod a+x clean.sh

Now you can run the script:

./clean.sh

Unfortunately, OS X will recreate these files again after the files are removed. Therefore, I create a cron job to remove them automatically:

sudo nano /etc/crontab

and put the following:

@hourly       root /path.to/script.sh

This will tell the system to run the script hourly.

Of course, you can change it to daily, weekly, monthly etc.

Situation 2: The shared folder is on OS X or Unix

The idea is very similar. You can do the same thing except that the script will be on the server side.

Or you can simply make the shared folder to read-only. Then Mac OS X can not create any annoying files. Here is an example on how to set up a read-only shared drive on Samba:

[Public]
        browseable = yes
        writeable = no
        path = /public
        force directory mode = 777
        force create mode = 777
        comment = This is a public directory
        create mode = 777
        directory mode = 777
        available = yes

Now you can say goodbye to .DS_Store and .AppleDouble.

–Derrick

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