Qin An

How IMGSaver Works on iPhone

2009-03-01T22:39:00.002+08:00

IMGSaver uses a piece of JavaScript to inject the following code into the current document.

(Sorry, I can't put the code into this blogger!! Blogger.com is a terrible blog!)

It shows up all images in the current web page (document). Then, user should click one of them. By this way this image pops up on the top of the history. User has to close Safari, so that the current history in memory is persisted into /var/mobile/Library/Safari/History.plist. Next time when IMGSaver is opened, the first item in the list is what the user just clicked. IMGSaver downloads once again by the URL, and saves it into local directory.

The keypoint is to inject the JavaScript into current document. IMGSave preinstalled a number of bookmark items, and one of them, "Display All Images", contains this java script code.

iPhone SwirlyMMS Conflicts with Other Software

2009-02-14T12:08:00.000+08:00

After I installed UCWeb, I found that the SwirlyMMS can't work. I need it, but I can't reinstall it. Last time when I updated the SwirlyMMS, it made my iPhone couldn't start. I had to reinstall the whole system, and lost all my contacts and data.

This time, I had to be very careful. I found that one more dynamic library was inserted into /System/Library/LaunchDaemons/com.apple.CommCenter.plist. I carefully removed it and let /Applications/SwirlyMMS.app/smshook.dylib be the only library. Then restarted iPhone, and the SwirlyMMS worked as usual. Also UCWeb works as well. I am not sure whether it can fully function. At least, it works as I expected.

A Simple Immune Method to USB-Disk Viruses

2007-06-23T22:07:00.000+08:00

This is the outline of a little presentation.

Introduction to the USB-Disk Viruses

Understand the USB-Disk viruses
USB-Disk viruses are a kind of viruses attached to USB removable disk like that of floppy disk very popular in 1990s. The virus from an infected computer is reproduced itself into the USB disk. When you plug this disk into a clean computer, the virus gets a chance to reside in the system, waiting for a new victim, while you are in complete ignorance of all this happened.
How they propagate
By default, Windows system enables an Auto Play function. When you plug in a USB disk or CD, Windows loads and executes a file named AutoRun.ini, which is the list of predefined tasks. The virus reproduces itself into the disk and modifies this file, so that when the file is executed, the virus is able to reside into the system.
How they damage your computer system
Nowadays the virus is not that simple as just propagating itself, whose only consequence is to lower the performance of the system. Today, almost every virus has its own mission embedded with spy wares and backdoors, which makes you in dangerous, for example, stealing your data files, ID information, and password of your bank account. Your computer probably becomes a zombie, from which hackers attack other victims.

An Immune Method to the USB-Disk Viruses

Open a command prompt by click Start -> Run. Input cmd and hit the return key.
In the command prompt, create a directory in the root directory of the USB drive with command:
mkdir AutoRun.ini
Move into this new directory with command:
cd AutoRun.ini
Create a new directory with command:
mkdir a...//
Exit the command prompt window with command:
exit
Remove the USB-Disk from the computer

Conclusion

A simple method without extensive computer knowledge
Immunity to the current known USB-Disk viruses and unknown ones in the future
Applicable to other removable storage devices such as digital cameras and MP3 players

Sample: Wildlife

2007-04-17T23:04:00.001+08:00

In the big woods, another spring will bring new leaves to the towering Nuttall oaks and sweet gums and centuries-old bald cypresses. Black bears will emerge from their dens in massive hollow sycamores, and bald eagle chicks will beg for food from their parents. Swallow-tailed kites and Swainson’s warblers will build nests, cottonmouths will uncoil and set off in search of unwary bullfrogs, and wood ducks will lead their young across bayous that are home to alligator gar as long as kayaks.

-Mel White, The Ghost Bird, National Geographic, Dec. 2005.

Shuan Yang Rou

2007-04-09T01:08:00.000+08:00

In Beijing, an international city in China, you can find many kinds of cuisines around the world, while, Shuan Yang Rou, instant-boiled mutton slices, is one of the finger-countable local flavors. After I first tried it when I came to Beijing ten years ago, it becomes one of my regular dining-outs. Outsiders often mix it up with hot pot, a flavor originated from Chongqing, a municipality in the southwest of China, whose pot contains thick soup, hot and spicy, while the pot of Shuan Yang Rou contains only clear water, and every taste is in a dish of special sesame jam, which is usually the top secret of a restaurant, since it can lure fussy goers far away. You fetch a piece of mutton, usually transported from the grassland of Inner Mongolia, with chopsticks, and put it into the boiling water for a little while, then, get it out and put it into the dish of sesame jam, and it is ready to serve. The action, Shuan in the clear water, is quite easy to learn, and people put a different meaning to this little verb, cheated or befooled, i.e., you are asked to do something but finally you get nothing reward at all.

Sample: Introducing People

2007-04-09T01:04:00.000+08:00

Borge, 43, lankily erect, fair-featured, and self-possessed, with long, ropy arms and cinnamon hair, was known, among other things, for his obsessive preparedness; he was a study in Nordi cool. Mike, 39, a dark-featured, dimpled South African-born Swiss, tightly muscled and with gigantic thighs, had a zesty kinetic spirit that gave the impression of a bull in a china shop; he thought of himself as a hot Latin and was more inclined to wing it. You could see the stamina shining out of his eyes. Thomas, 39, a compact and talkative Swiss, quick to laugh, with twinkly blue eyes and an underlying edge, was fastidious about safety and had a professional alpine guide’s love of detail. At one point, he was a prospective third partner on Mike and Borge’s trek to the Pole in the dark, but, for reasons which will be explained later, they went their separate ways.

Marguerite Del Giudice, Arctic Dreams & Nightmares, National Geographic, Jan., 2007.

From Home to Office

2007-04-03T12:59:00.000+08:00

The office of Qilinsoft is located at Wangfujing, the downtown of Beijing. Everyday I take subway Line 13 from Huilongguan station, a large community in the north of Beijing, to the eastern terminal Dongzhimen station, located at the northeast corner of the Second Ring road. There, I change to subway Line 2 to south, and arrive at Jianguomen station, an interchange station. Without exiting the station, I change to subway Line 1, and arrive at Wangfujing station. Follow the sign of the exit to the Oriental Plaza. The office is on the 16th floor, Block E1.

Travel by Train

2007-03-23T22:54:00.001+08:00

If I could get a train ticket, I would like to travel by train instead of by air. In China, more likely trains can arrive on time. There is a larger space for you to walk around in a train carriage than that of in a plane cabin. I am happy to enjoy flowing into beautiful scenery along with steel rails, whereas you may find it boring with unchanged sunshine and clouds. There are a lot of interesting people, with whom I can share various experiences, and it makes the journey even shorter than flying in the air.

Homework: 5-Sentence Paragraph as How You Will Open a Meeting

2007-03-20T22:18:00.000+08:00

Good afternoon, everybody! In today’s meeting, we will discuss the policy of our internal CVS system. The list of topics has been sent out this morning and hope that everybody can contribute to this meeting. I would like to thank colleagues from our IT department for their coming since they will help us in system installation and administration. We hope that we can work out a document on the policy in this 1-hour meeting.

Perks and Drags of Our Current Job

2007-03-13T11:25:00.000+08:00

We are having an English training program recently. The first home work is to write 5 sentences on the perks and drags of our current job, dream job and future career path. Here is mine.

As a TechLead of the runtime components of the Galileo Project, I always have to catch up with various new technologies in the industry matured in an even shorter period of time. It makes me sometimes frustrated while we are hammering our product in office, there is a new technology mushroomed out in the world elsewhere. Further, we have to be more careful and patient to every single step in the lifecycle of software development, from coding to QA. A recent famous accident of the F-22 Raptor Fighter of the US AF provides a worldwide example, whose Global Positioning Inertial Navigation Systems crushed when it flew across the International Date Line in its maiden deployment. These must be the eternal challenges a software engineer has to face in the technology career.

Start Local XWindow on Microsoft Windows Platform

2007-02-17T10:47:00.000+08:00

In a UNIX network, it is quite natural to connect to an XWindows server from local machine. If your daily work is on a Windows machine, and occasionally do something requiring an XWindows, there are two ways provided by cygwin package, which is a simulator of UNIX environment on a Microsoft Windows platform.

You can start an X server on UNIX side, and use an X client on Windows side. The terminal is a true XWindows, as if you were working locally on the remote UNIX machine. This approach consume more resource on the server side, and sometims it is infeasible in case there are multiple users doing same thing in an organization.

Another way is to start up an X server on local Windows side. Cygwin provides an simulated UNIX environment. Then telnet to remote UNIX machine and direct the X connection back to the local one. Here are the detailed steps.

You should install cygwin + X11R6 package.

On your host 10.10.1.123, run

/usr/X11R6/bin/startxwin.bat

to start local XWindows.

In the shell, add remote host:

xhost 10.10.1.35

Then telnet to 10.10.1.35, assuming you are in csh, and set DISPLAY environment variable:

setenv DISPLAY 10.10.1.123:0.0

Then you can start any XWindows application. Do a test:

xterm &

You will see a UNIX shell window on your Windows desktop. An interesting feature of this approach is that, unlike the first method you get a window for everything on UNIX side, with the second method, each XWindow is dependent. They can be operated in same way as a Windows' window.

Kill Process by Name on UNIX

2007-02-17T10:44:00.000+08:00

Here is a ksh script to kill processes by name.
Usage: kill processName

---------------- cut here ---------------------
#!/usr/bin/ksh

str="$1"

ps -ef grep "$str" {
while read aline;do
cmd=`echo $aline awk '{ print $9 }'`
if [ [ $cmd = $0 ] ]; then
continue
fi

cmd=`echo $aline awk '{ print $8 " " $9 " " $10 }'`
if [ [ $cmd = "grep" ] ]; then
continue
fi

cmd2=`echo $cmd grep "$str"`
if [ [ $cmd2 = "" ] ]; then
continue
fi

print "$aline"
pid=`echo $aline awk '{ print $2 }'`
print "kill pid = $pid"
kill -9 $pid
done
}

---------------- cut here -----------------------

Default Transaction Attribute of an EJB is different among WebLogic/WebSphere/JBoss

2007-02-14T16:53:00.000+08:00

Here is another difference between WebLogic and WebSphere/JBoss. For WebLogic, the default transaction attribute of an EJB is TX_NOT_SUPPORTED if it is not explicitly defined in ejb-jar.xml. There is no transaction context in the call to the EJB. However, JBoss and WebSphere, the default behavior is different, and there is a new transaction.

WebLogic Only Supports String Type in ActivationSpec

2007-02-14T15:36:00.000+08:00

Unlike WebSphere and JBoss, WebLogic only supports java.lang.String type properties in ActivationSpec. WebLogic claims it always strictly follows J2EE specification. Developer can specify properties with wrapped primitive types on Resource Adaptor level in ra.xml:

<resourceadapter>
<resourceadapter-class>
mypackage.ResourceAdapterImpl
</resourceadapter-class>
<config-property>
<config-property-name>convertRate</config-property-name>
<config-property-type>java.lang.Integer</config-property-type>
<config-property-value>123</config-property-value>
</config-property>
……

Maybe it is true that this is the right way, but it is obviously inconvenient to specify only String type in ActivationSpec.

Code Coverage Test with EMMA Utility

2007-02-03T00:46:00.000+08:00

Unit test is an essential stage in a software development lifecycle. After the code of features is completed, developer is required to design a number of test cases to guarantee the software performs desired functions.

There is no simple objective criteria how many test cases enough to assure the quality of a software. Being lack of deep knowledge of implementation, project managers reluctantly accept the test plan from developers. The question can not be answered by developer either. Since it is infeasible to exhaust every possible test scenario, the developer is eager to know the minimum number of cases that can touch the most part of the code.

The code coverage test is probably a feasible objective measure. A little open-source utility, EMMA, can generate a precise picture how much percentage the code is covered after the execution of a test suite. The data is broken down to packages, classes, and even methods. It helps the developer design new cases to increase the percentage rather than to repeat similar cases.

EMMA provides a lot of features, and I am very impressed with two of them: It reports rich coverage analysis without introducing significant overhead during either build or execution time. It is simple, lightweight, and easy to probe classes running in a J2EE container. Here is an example where the test suite is designed for foo.jar used by a JBoss application server.

First copy emma.jar into the lib directory of the application server.

Create an instrumented version of foo.jar. Put emma.jar into environment variable CLASSPATH. Create a directory output for the instrumented classes. Execute command java emma instr -d output -ip foo.jar. There is a file coverage.em created under the current working directory. Then package the instrumented classes under directory output into a new version of foo.jar, and replace the JAR file in the application server.

Start the application server. Execute the test suite as usual. Then stop the application server. There will be a raw result file coverage.ec generated under the directory where the application server is launched, in my case, C:\jboss-4.0.4.GA\bin\coverage.ec.

Generated the plain text and HTML reports with command java emma report -r txt,html -in coverage.em -in C:\jboss-4.0.4.GA\bin\coverage.ec. The plain text report is generated in the current working directory coverage.txt. The report in HTML format is generated as coverage\index.html.

A USB Disk Virus

2007-01-27T08:54:00.001+08:00

My younger sister came to Beijing, and gave me her little USB disk. She said there was a virus. It was effected in the network in her office. There are a lot of viruses wandering on their network from computer to computer. Even they installed various virus killers, the situation remained unchanged.

I had no idea about USB viruses. Maybe this is the first time I was facing this kind of thing. I plugged the disk into the USB port of my notebook. I am not afraid of it because I have Norton Anti-Virus. After scaned, Norton reported there is a malware named iexplorer.exe under iexplorer directory. The virus tries to fool user it is a copy of the famous Internet Explorer!

How does it take action? When we click the icon of the removable disk in the window of My Computer, by default, autorun.inf on this disk is loaded and something will be executed. At this moment, the virus hides itself in memory waiting for the opportunity to copy itself to a new USB disk.

It is possible to disable the autorun feature by modifing some key values in the Registry of Windows. But it is not a wise idea. More often we need this feature. There is a best practice in using a USB disk or other removable devices. You can keep pressing the Shift key when you plug the disk. In this case autorun is skipped. And then, open your virus scanner. Remove autorun.inf. For a USB disk, you actually don't need it. Be cautious after you use your disk in other computers.

Reading File in a Multi-Thread Environment

2007-01-21T02:33:00.000+08:00

A file can be opened separately in a multi-thread environment, but it can not be read independently. It seems there is a unique reading pointer inside OS. When a thread reads some bytes, the pointer is advanced, and other threads will continue reading from the new position. To control the reading behaviour, file operations must be synchronized. Look at the following piece of code:

unsigned long pos = 0;
unsigned long bytesRead = 0;
for (;;) {
    mutex_->captureObject();
    fseek(f, pos, SEEK_SET);
    bytesRead = fread(buffer, 1, BUFFSIZE, f);
    mutex_->releaseObject();
    if (bytesRead <= 0)
        break;
    pos += bytesRead;
    .......
}

A mutex object is used to synchronize file operations.

Change IP Address in a Script

2007-01-13T00:37:00.000+08:00

We usually change the IP address of the network card of our computer with a graphic tool. This work can also be done in a command prompt. Sometimes it is useful. Follow me:

C:\>ipconfig
Windows 2000 IP Configuration

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . :
IP Address. . . . . . . . . . . . : 10.0.127.235
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 10.0.127.1

C:\>netsh
netsh>i
interface>i
interface ip>sh a

Configuration for interface "Local Area Connection"
DHCP enabled: No
IP Address: 10.0.127.235
SubnetMask: 255.255.255.0
Default Gateway: 10.0.127.1
GatewayMetric: 1
InterfaceMetric 1

interface ip>set a "Local Area Connection" static 192.168.16.44 255.255.255.0 192.168.16.5 1
Ok.

interface ip>sh a

Configuration for interface "Local Area Connection"
DHCP enabled: No
IP Address: 192.168.16.44
SubnetMask: 255.255.255.0
Default Gateway: 192.168.16.5
GatewayMetric: 1
InterfaceMetric 1

interface ip>exit

C:\>ipconfig

Windows 2000 IP Configuration

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . :
IP Address. . . . . . . . . . . . : 192.168.16.44
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.16.5

If you want to set it as DHCP, try this:

interface ip>set a "Local Area Connection" source=dhcp

Administrator permission is required for this work.

Amazon Forest to Farms

2007-01-12T21:43:00.000+08:00

I was heavily shocked by the cover of the January release of the National Geographic when I saw it today on a bookshelf of the Wangfujing Bookstore, Beijing. The title "Amazon Forest to Farms" is printed over a picture of farmland, a common landscape of the vast plain of central China. The land is cultivated perfectly by advanced machinery, except a little lonely tree standing in the middle. Nobody can imagine it is a snapshot of the Amazon region. Amazon forest is dubbed as the lung of the Earth. At this moment I just feel hard to breath. The little tree is telling a horrific story why it is there and how long it will be there.

When I showed the magazine to my friend, a foreigner in IT industry as myself, he has no semantic linkage between Amazon and Forest, of course, no idea why this title goes to the cover page of this famous magazine. He talked to me the Amazon in the United States and made me astonished.

The story is quite simple. Where did these trees go? They went to paper mills, to publishers’ workshops, to shelves of bookstores and finally the Internet. The Amazon in the South America might disappear soon, but it lives on the Internet in the United States of America. There is no evidence that the Amazon in the digital era can last forever.

Disable JIT to Obtain Line Number in Stack Trace

2007-01-12T00:07:00.000+08:00

IBM JVM can optimize a Java class. In this case, when an exception's stack trace is printed, you may find there is no line number for some classes. It is diffuclt for you to figure out the problem:

at com.vitria.bpe.runtime.EventUtil.isTimerEvent(Compiled Code)
at com.vitria.bpe.process.states.BPBasicStateImpl.applyRulesRegular(Compiled Code)
at com.vitria.bpe.process.states.BPActionStateImpl.onEntry(Compiled Code)
at com.vitria.bpe.process.states.BPBasicStateImpl.applyPolicy(Compiled Code)

We can disable JVM's JIT feature in following way:

Go to WebSphere's console: Application servers > server1 > Process Definition > Java Virtual Machine
And select the check box of "Disable JIT".
Save the new configuration and restart WebSphere.

Manually Install Customer Service in WebSphere 6.1

2007-01-11T21:15:00.000+08:00

Manually install the service:

Open the console of WebSphere. Go to Servers -> Application Servers. Select server1 for example.
On Configuration tab, select Server Infrastructure -> Administration -> Administration Services.
On Configuration tab, select Extension MBean Provider.
Click New.
Input Name as MyServiceMBean, Classpath as ${WAS_LIBS_DIR}/myjar.jar, Description as Administration MBean. Click OK, and save the changes. The JAR file contains the classes implementing this service.
Select the record MyServiceMBean just created. The bean name MyServiceMBean is defined in the XML MyService.xml file.
Select the extensionMBeans on Additional Properties column.
Click New.
Input DescriptorURI as MyService.xml, type as MyServiceMBean. Click OK, and save the changes.
Go to Servers -> Application Servers. Select server1.
On Configuration tab, select Server Infrastructure -> Administration -> Custom Services.
Click New.
Check the option Enable service at server startup. Input Classname as mypackage.MyServiceMBean, Display Name as "My Service MBean", Classpath as ${WAS_LIBS_DIR}/myjar.jar. Click OK, and save the changes.
Restart WebSphere server.