It’s been a long time since I last blogged. Today I have some exciting news for you, as I have ported Eleganz, my homebrew manager, to the Cobra ODE.
A little while ago, I tweeted that if Cobra ever released their device and did provide an open source library for integration of other managers, I would port Eleganz to it, and today I am fulfilling that promise. I would like to thank the guys over at ps3crunch.net and ps3hax.net for testing this for me, particularly Abkarino, hyappon, freddy, magneto and Xodus69.
When I released Eleganz in November 2011, I left out one small thing on the TODO list, I wanted to see someone pick it up and add the code to exitspawn to actually make Eleganz execute the homebrew apps, but no one did that in almost a year now. I am a bit disappointed that the ps3 scene (homebrew devs, not users) didn’t pick it up, but it looked like no one was interested in maintaining Eleganz in my place. Today, I am happy to see that Eleganz is not throw-away code, as it can be useful to ODE users.
I can understand why Eleganz didn’t have much appeal in the world of CFW (it was originally intended to run on OFW if my HEN ever worked), but with the ODEs running on OFW, it’s perfect for the job. It’s simple, it’s beautiful and customizable!
Not only can Eleganz list the games from the Cobra ODE and allow you to select your iso, but it will also allow you to list and run homebrew apps that you can embed in the ISO file. This way you can get access to all your homebrew in a single place, without the need to restart the PS3 or boot the homebrew’s iso from the ODE. You can just extract the eleganz iso, and add homebrew apps (that are re-signed for running from a BD drive) to the iso’s PS3_GAME/USRDIR/HOMEBREW directory and recreate the iso with the cobra tool, and that’s it.
Note that this is not an indication of me getting back into the hacking scene. I have given up on the HEN long ago as I realized that there was no way (that I could find) to run homebrew on OFW, unless they are running from a disc. I may keep improving Eleganz in the near future, but I do not plan to do anything more than that for the ps3 scene at this point.
I would also like to tell everyone that there’s no need to worry, Eleganz will not become cobra-specific, as any feature I’d implement will benefit CFW as well as ODE users. I will be releasing an updated version for CFW users soon.
I’d also like to thank magneto and the Cobra team for offering to send me a Cobra ODE as a gift for porting Eleganz to it. Once I receive it, I plan on adding disc dumping capabilities to Eleganz and improve the user experience a little without relying on others to test it for me.
I have just released a new version of libnice, the NAT traversal library.
Version 0.1.4 has a few bug fixes but the major changes are the addition of an SDP parsing and generation API.
You can now more easily generate your credentials and candidates and parse them with a single API call, making it much easier to exchange candidates and establish a successful connection.
Also, I have added three examples to the examples/ subdirectoy from the libnice source tree. Those examples should help anyone learn how to use libnice and what to do in order to establish a successful connection.
The first example, simple-example.c will create a new agent, and gather its candidates and print out a single line to paste on the peer. It uses the signals to asynchronously wait for events and continue the code execution.
The second example, threaded-example.c, will run the mainloop on the main thread and do everything else sequentially in another thread, waiting for signals to release the libnice thread to continue processing.
The final example, sdp-example.c, is based on the threaded example but uses the new SDP generate/parsing API to generate the candidates and credentials line to exchange between the two instances. It will base64 the SDP to make it all fit into a single line, making it easier to exchange the SDP between clients without having to parse the multi-line SDP in the example, keeping it small and concise.
I hope you will find this release useful, let me know if you have any comments.
You can get the latest version here and the documentation has been updated here.
Last year, in January, I decided to have some fun and write a homebrew application using the EFL libraries. I decided to work on a homebrew manager.. basically a replacement to the XMB. It went really well, and the development was really fast, and it was all thanks to the awesome API and capabilities of the EFL libraries. However, I became busy and was unable to continue… also, it was a bit slow and without proper hardware acceleration, it wouldn’t be as good as I hoped for, so I put the project on the side.
After many months, in September, thanks to gzorin’s work, we finally had a working and usable GL implementation and the EFL apps automatically gained from it by becoming hardware accelerated. My homebrew manager was much better! but I still needed to finish a few things and I didn’t have time so I put to rest again.
Today, I have decided to release this homebrew application, *as is* for everyone’s enjoyment! This means that it is not fully working, it might still have some bugs here and there, but it is still a homebrew app that people can use and have some fun with. Most importantly it will serve 4 purposes :
Maybe re-awaken this dying PS3 homebrew scene
Be a good “exercise to the community” for finishing it up
Be a good example of what can be done with the EFL
Bring non-developers into writing EFL themes for the app
I introduce to you, Eleganz! The Elegant Homebrew Manager! A little homebrew app that lets you install pkg files and run your games directly from it. Here is the mandatory screencast video :
I have published my app in both github and on ps3dev’s gitorious. and you can also download a pre-compiled .pkg for your PS3 to have fun with it.
Here are some highglights of the application (features, limitations and bugs) :
The whole User Interface is completely customizable with themes
Installs .pkg files locally to its own data directory (won’t be visible in the real XMB, unless someone reverses the database format)
Does not yet run games (it’s for you to do it, use ps3load as reference maybe…)
Current theme is missing proper theme/images for the progressbar windows (default exquisite/E17 theme used)
System freezes for a few milliseconds when it tries to load a game’s background image (might be fixed if we implement a pthread library and threading support in the EFL)
Apparently crashes when it exits (bug)
The homebrew app comes with two themes, a dark and light theme. I like the dark one so I chose that as the default (oh, ignore that grey background ‘default’ one from that screencast video, that was just for testing). I wrote the user interface for the theme (the Edje files) while opium designed all the graphics. The theme engine in the EFL is extremely powerful, so I hope I will see tons of themes popping up. And I do not mean “change the images” themes, I want real themes, where the whole UI is different, a vertical XMB, a circular one, a 3D theme with perspective/depth for the icons, a dynamic/moving background, etc… You can learn about the .edj/.edc file format here and don’t forget to check the EDC reference wiki.
I hope to see the community pick this up and have fun with it!
That’s about it, enjoy it, and send me your patches! I’ll be waiting 🙂
p.s: Forgot to say that the rules/naming conventions/etc.. of the EDC files are explained here. If a .edj file doesn’t have the appropriate parts/groups, then it will be ignored and will not show on the UI.
p.p.s: You can install the EFL on windows and have access to edje_cc to compile your .edc into .edj.
p.p.p.s: Damn, I keep forgetting stuff.. by the way, the whole Eleganz application works just fine on the PC too, I did all my development on the PC (that screencast was actually on Linux), *then* I tried it on the PS3 and it just worked.. so for theme development, it should be pretty easy to test without the need of a PS3.
More and more people are doing video conferencing everyday, and for that to be possible, the video has to be encoded before being sent over the network. The most efficient and most popular codec at this time is H264, and since the UVC (USB Video Class) specification 1.1, there is support for H264 encoding cameras.
One such camera is the Logitech C920. A really great camera which can produce a 1080p H264-encoded stream at 30 fps. As part of my job for Collabora, I was tasked to add support for such a camera in GStreamer. After months of work, it’s finally done and has now been integrated upstream into gst-plugins-bad 0.10 (port to GST 1.0 pending).
One important aspect here is that when you are capturing a high quality, high resolution H264 stream, you don’t want to be wasting your CPU to decode your own video in order to show a preview window during a video chat, so it was important for me to be able to capture both H264 and raw data from the camera. For this reason, I have decided to create a camerabin2-style source: uvch264_src.
Uvch264_src is a source which implements the GstBaseCameraSrc API. This means that instead of the traditional ‘src’ pad, it provides instead three distinct source pads: vidsrc, imgsrc and vfsrc. The GstBaseCameraSrc API is based heavily on the concept of a “Camera” application for phones. As such, the vidsrc is meant as a source for recording video, imgsrc as a source for taking a single-picture and vfsrc as a source for the viewfinder (preview) window. A ‘mode’ property is used to switch between video-mode and image-mode for capture. The uvch264_src source only supports video mode however, and the imgsrc will never be used.
When the element goes to PLAYING, only the vfsrc will output data, and you have to send the “start-capture” action signal to activate the vidsrc/imgsrc pads, and send the “stop-capture” action signal to stop capturing from the vidsrc/imgsrc pads. Note that vfsrc will be outputting data when in PLAYING, so it must always be linked (link it to fakesink if you don’t need the preview, otherwise you’ll get a not-linked error). If you want to test this on the command line (gst-launch) you can set the ‘auto-start’ property to TRUE and the uvch264_src will automatically start the capture after going to PLAYING.
You can request H264, MJPG, and raw data from the vidsrc, but only MJPG and raw data from the vfsrc. When requesting H264 from the vidsrc, then the max resolution for the vfsrc will be 640×480, which can be served as jpg or as raw (decoded from jpg). So if you don’t want to use any CPU for decoding, you should ask for a raw resolution lower than 432×240 (with the C920) which will directly capture YUV from the camera. Any higher resolution won’t be able to go through the usb’s bandwidth and the preview will have to be captured in mjpg (uvch264_src will take care of that for you).
The source has two types of controls, the static controls which must be set in READY state, and DYNAMIC controls which can be dynamically changed in PLAYING state. The description of each property will specify whether that property is a static or dynamic control, as well as its flags. Here are the supported static controls : initial-bitrate, slice-units, slice-mode, iframe-period, usage-type, entropy, enable-sei, num-reorder-frames, preview-flipped and leaky-bucket-size. The dynamic controls are : rate-control, fixed-framerate, level-idc, peak-bitrate, average-bitrate, min-iframe-qp, max-iframe-qp, min-pframe-qp, max-pframe-qp, min-bframe-qp, max-bframe-qp, ltr-buffer-size and ltr-encoder-control.
Each control will have a minimum, maximum and default value, and those are specific to each camera and need to be probed when the element is in READY state. For that reason, I have added three element actions to the source in order to probe those settings : get-enum-setting, get-boolean-setting and get-int-setting. These functions will return TRUE if the property is valid and the information was successfully retrieved, or FALSE if the property is invalid (giving an invalid name or a boolean property to get_int_setting for example) or if the camera returned an error trying to probe its capabilities. The prototype of the signals are :
gboolean get_enum_setting (GstElement *object, char *property, gint *mask, gint *default); Where the mask is a bit field specifying which enums can be set, where the bit being set is (1 << enum_value). For example, the ‘slice-mode’ enum can only be ignored (0) or slices/frame (3), so the mask returned would be : 0x09 That is equivalent to (1 << 0 | 1 << 3) which is : (1 << UVC_H264_SLICEMODE_IGNORED) | (1 << UVC_H264_SLICEMODE_SLICEPERFRAME)
gboolean get_int_setting (GstElement *object, char *property, gint *min, gint *def, gint *max); This one gives the minimum, maximum and default values for a property. If a property has min and max to the same value, then the property cannot be changed, for example the C920 has num-reorder-frames setting: min=0, def=0 and max=0, and it means the C920 doesn’t support reorder frames.
gboolean get_boolean_setting (GstElement *object, char *property, gboolean *changeable, gboolean *default_value); The boolean value will have changeable=TRUE only if changing the property will have an effect on the encoder, for example, the C920 does not support the preview-flipped property, so that one would have changeable=FALSE (and default value is FALSE in this case), but it does support the enable-sei property so that one would have changeable=TRUE (with a default value of FALSE).
This should give you all the information you need to know which settings are available on the hardware, and from there, be able to control the properties that are available.
Since these are element actions, they are called this way :
Apart from that, the source also supports the GstForceKeyUnit video event for dynamically requesting keyframes, as well as custom-upstream events to control LTR (Long-Term Reference frames), bitrate, QP, rate-control and level-idc, through, respectively, the uvc-h264-ltr-picture-control, uvc-h264-bitrate-control, uvc-h264-qp-control, uvc-h264-rate-control and uvc-h264-level-idc custom upstream events (read the code for more information!). The source also supports receiving the ‘renegotiate’ custom upstream event which will make it renegotiate the according to the caps on its pads. This is useful if you want to enable/disable h264 streaming or switch resolution/framerate easily while the pipeline is running; Simply change your caps and send the renegotiate event.
I have written a GUI test application which you can use to test the camera and the source’s various features. It can also serve as a reference implementation on how the source can be used. The test application resides in gst-plugins-bad, under tests/examples/uvch264/ (make sure to run it from its source directory though).
You can also use this example gst-launch pipeline for testing the capture of the camera. This will capture a small preview window as well as an h264 stream in 1080p that will be decoded locally :
That’s about it. If you are interested in using uvch264_src to capture from one of the UVC H264 encoding cameras, make sure you upgrade to the latest git versions of gstreamer, gst-plugins-base, gst-plugins-good and gst-plugins-bad (or 0.10.37+ for gstreamer/gst-plugins-base, 0.10.32 for gst-plugins-good and 0.10.24 for gst-plugins-bad, whenever those versions get released).
I would like to thank Collabora and Cisco for sponsoring me to work on this great project, it couldn’t have been possible without them!
If you have any more questions about this subject, feel free to contact me.
After the variousblogposts about it, and the talk I gave at the GStreamer Conference, there was a lot of interest in the GstFilters library that I’ve been working on. The original plan was for it to get merged into gst-plugins-base, however, it seems like that’s not going to happen. The GStreamer developers would prefer seeing some of its features integrated into the core, but they don’t want the library itself. So I have finally decided to release it as a standalone package so everyone interested can already start using it.
As features from GstFilters will slowly get merged into the core of GStreamer, I will adapt the library to make use of these new features, reducing its internal code. However I believe it is still very useful to have Gstfilters as it’s a very simple library for those who are not familiar with GStreamer. Also the concept of the ‘filters’ is very different from the GstElements because an element can only be added once in a pipeline but filters can be added any number of times in a pipeline (a GstFilter doesn’t represent an actual element, it’s more like a helper function for “create and link these elements for me”). Also the points I’ve made about the steep learning curve and the robustness checks will still be valid even after the Gst core makes dynamic pipeline modifications easier.
GstFilters are now released and will be hosted on freedesktop.org under Farstream’s project. While Farstream users will be the most interested in this library and it is very useful for VoIP/Farstream users, it can also be used for non VoIP applications.
On a similar note, the Farsight-Utils library and API that I presented at the GStreamer Conference has been modified to make it even simpler. The library has been renamed into Farstream-IO since it basically takes care of all the Input/Output to the Farstream conference. The new API is based on a single object now, a FsIoPipeline that you create (which is a subclass of GstPipeline) and to which you register the FsConference/FsSession/FsStream. All the methods from the previous Farsight-Utils classes (FsuConference, FsuSession and FsuStream) will stay the same but will be merged into this single FsIoPipeline class, making everything easier and you’d only need to keep track of a single object.
The FsIo API will be merged into Farstream and released for the next version.
About 2 weeks ago, I was in Talca, Chile for the ExpoLibre 2011 conference. It was really awesome, I had one of the best experiences as a speaker!
One of the particularities of that conference, is that it’s organized by the university and its target audience is students, teachers and enthusiasts in open source. The majority of the attendees were not open source developers, but they were people who wanted to learn more about it.
For that reason, this was my very first “motivational talk” rather than my usual technical talks that I’ve given in the past, and I loved it!
Another interesting point was that the audience was mostly speaking Spanish, and not everyone understood English, so I had my colleagues (Reynaldo Verdejo and Thibault Saunier) there to translate what I was saying. That created a very pleasant experience as I had time to relax between each slide while they were translating, and it also made the talk more casual and interactive. I wasn’t nervous for the first time, and it felt great! 🙂
After the talk, I received some very interesting questions and I thoroughly enjoyed answered everyone of them. I saw a lot of people who were interested and I felt like I connected with everyone and I was able to touch them with my ideas. If I was able to change at least one attendee’s perception of open source, and hopefully get them involved in various FLOSS projects, then my mission is a success!
Today, the organizers of the ExpoLibre conference sent me the video recording of my talk, and I’ve shared it on youtube so everyone can listen to what I had stay. I hope everyone enjoys it as much as I enjoyed doing it.
On a final note, I’d like to say that Chile is a beautiful country. I stayed there for almost two weeks, and even though travel from/to Canada is a pain, it was totally worth it! I can’t wait for the next opportunity for me to go there.
Update : Some people complained about the rhythm being broken because of the translation to spanish, so I asked here for anyone who wants to contribute, to edit the video and crop the non-english sections, so english-only speaking people can view the talk in one constant rhythm/flow without the interruptions by the translators.
Patrick Donnelly, one of the people who saw the video (and my request for an edit) did it and commented below with a link to an english-only version of my talk (the intro and questions part were left untouched at my request). Here it is for those who need it :
And here is the original, unedited version of my talk I gave, enjoy it!
I have finally decided to blog about my netem tool that I wrote a couple of months ago.
First, the introductions, netem is a kernel component for controlling QoS, rate control and various network properties that allows you to emulate a network by modifying the kernel’s IP stack’s queue disciplines. You can read more about it here : http://www.linuxfoundation.org/collaborate/workgroups/networking/netem
The issue I had with the netem queue was that it was hard/complicated to use and required a fair bit of reading and understanding of how the Linux IP stack worked in order to even use it properly. I needed an easy to use tool in order to test multiple network properties quickly. I looked around for a tool that would help me with that and only found phpnetemgui which is a very old piece of code, not even compatible with the latest php versions and which requires you to run a server on localhost and give sudo access to the web server… I didn’t like that, so I wrote my own tool for easy netem configuration (thanks to the phpnetemgui code, it was helpful in providing some of the commands).
The README has all the information you need in order to use it, so make sure you read it, but let me summarize a bit how it works.
Netem uses a CSV file in which you can set multiple rules, each with its own set of properties (10% packet loss, 5% duplicated packets, 100ms delay with 25ms of jitter, limit bandwidth to 256Kbps, etc..). Each rule has a name and you can have multiple rules with the same name (limit bandwidth to 256Kbps for IP 18.104.22.168, and 512Kbps to IP 22.214.171.124). All these sub-rules with the same name will be considered as being a single rule. You can run netem on an interface, giving it the CSV filename and the name of the rule that you want to activate and it will output all the commands you need to execute in order to emulate the network as specified in the rules from the CSV file.
To actually run the network emulation, just pipe the output to ‘sh’, for example : ./netem eth0 my_rules.csv 256kbps | sudo sh
The reason I did this was to help my colleague Olivier Crete who was working on TFRC (Tcp-Friendly Rate Control) for RTP in Farsight. He needed to be able to emulate various network configurations, change the bandwidth limitations, introduce packet drop, etc.. and see how TFRC would react to make sure that the video/audio stream’s quality stays acceptable and the bitrate calculation adapts correctly to changing network conditions. I’ve also been recently working on HLS (HTTP Live Streaming) support in GStreamer and I’ve used the tool to make sure that the HLS stream correctly adapts to the network bandwidth and switches the bitrate/resolution correctly. This tool has been a great help in doing all these tests, so it’s time now to share it with whoever it might interest.
I’ll conclude with these example outputs for three different rules (taken from the provided test.csv in git) :
Limit inbound and outbound bandwidth to 1024Kbps (2 sub-rules)
kakaroto@kakaroto:~/coding/netem$ ./netem wlan0 test.csv 1024kbps
ip link set dev ifb0 up
tc qdisc del dev wlan0 ingress
tc qdisc add dev wlan0 ingress
tc filter add dev wlan0 parent ffff: protocol ip u32 match u32 0 0 flowid 1:1 action mirred egress redirect dev ifb0
tc qdisc del dev ifb0 root
tc qdisc add dev ifb0 root handle 1: prio bands 10
tc qdisc del dev wlan0 root
tc qdisc add dev wlan0 root handle 1: prio bands 10
tc qdisc add dev ifb0 parent 1:1 handle 10: htb default 1
tc class add dev ifb0 parent 10: classid 0:1 htb rate 1024kbit ceil 1024kbit burst 0 cburst 0
tc qdisc add dev wlan0 parent 1:1 handle 10: htb default 1
tc class add dev wlan0 parent 10: classid 0:1 htb rate 1024kbit ceil 1024kbit burst 0 cburst 0
tc filter add dev wlan0 protocol ip parent 1:0 prio 1 u32 match ip src 0.0.0.0/0 match ip dst 0.0.0.0/0 flowid 10:1
tc filter add dev ifb0 protocol ip parent 1:0 prio 1 u32 match ip src 0.0.0.0/0 match ip dst 0.0.0.0/0 flowid 10:1
A rule to add 100ms of delay with 25ms of jitter using a normal distribution with 25% of correlation
kakaroto@kakaroto:~/coding/netem$ ./netem wlan0 test.csv delay
tc qdisc del dev wlan0 root
tc qdisc add dev wlan0 root handle 1: prio bands 10
tc qdisc add dev wlan0 parent 1:1 handle 10: netem delay 100ms 25ms 25% distribution normal
tc filter add dev wlan0 protocol ip parent 1:0 prio 1 u32 match ip src 0.0.0.0/0 match ip dst 0.0.0.0/0 flowid 10:1
A rule that emulates various packet loss, delay, duplication, packet reordering, rate control, for both inbound and outbound connection with IP and port matching (3 sub-rules)
kakaroto@kakaroto:~/coding/netem$ ./netem wlan0 test.csv test1
ip link set dev ifb0 up
tc qdisc del dev wlan0 ingress
tc qdisc add dev wlan0 ingress
tc filter add dev wlan0 parent ffff: protocol ip u32 match u32 0 0 flowid 1:1 action mirred egress redirect dev ifb0
tc qdisc del dev ifb0 root
tc qdisc add dev ifb0 root handle 1: prio bands 10
tc qdisc del dev wlan0 root
tc qdisc add dev wlan0 root handle 1: prio bands 10
tc qdisc add dev wlan0 parent 1:1 handle 10: htb default 1
tc class add dev wlan0 parent 10: classid 0:1 htb rate 256kbit ceil 256kbit burst 0 cburst 0
tc qdisc add dev wlan0 parent 10:1 handle 11: netem loss 0.5% 25% duplicate 5% delay 100ms 50ms 25% distribution pareto reorder 1% limit 1000
tc qdisc add dev wlan0 parent 1:2 handle 20: netem loss 0.5% 50% limit 1000
tc qdisc add dev ifb0 parent 1:1 handle 10: netem loss 5% reorder 5% limit 1000
tc filter add dev wlan0 protocol ip parent 1:0 prio 1 u32 match ip dst 126.96.36.199/32 match ip dport 1234 0xffff flowid 10:1
tc filter add dev wlan0 protocol ip parent 1:0 prio 2 u32 match ip sport 4321 0xffff flowid 10:1
tc qdisc add dev wlan0 parent 1:3 handle 30: pfifo
tc filter add dev wlan0 protocol ip parent 1:0 prio 3 u32 match ip src 0.0.0.0/0 match ip dst 0.0.0.0/0 flowid 30:3
tc filter add dev ifb0 protocol ip parent 1:0 prio 1 u32 match ip src 188.8.131.52/32 match ip sport 1234 0xffff flowid 10:1
tc qdisc add dev ifb0 parent 1:2 handle 20: pfifo
tc filter add dev ifb0 protocol ip parent 1:0 prio 2 u32 match ip src 0.0.0.0/0 match ip dst 0.0.0.0/0 flowid 20:2
I’m a programmer, a developer, a hacker. I’m mostly involved with the Open Source community and I try to promote open source development as much as I can. Unfortunately, most of the time when I tell someone that I’m a “developer”, they don’t understand the concept, and when I start talking about open source, they understand me even less.
The world is full of people with different backgrounds, with different references and we don’t always understand each other. As most of you who read my blog would probably know, I’m involved in the PS3 hacking scene, and I see a lot of misinformed people, and I read a lot of things that don’t make any sense to me. This is because most people don’t understand the world that we (developers/hackers) come from and things tend to be misinterpreted.
This message is for everybody, it’s intent is to open a window into our world so people can understand us better. I don’t have the audacity to explain everything about programming in this text, but I will try to formulate in terms easy to understand the general idea behind it. While most of this post will be generic and intended to anyone, there will be a paragraph that will address some of the recent issues surrounding the PS3 and Sony. This post will probably be very long and I’m sorry, I don’t think I have a shorter version for those who get bored easily.
1 – Programming
If you’re familiar with or understand programming, you may skip this section, as it might be a bit boring, otherwise, read on, it should explain what you need to know to understand the rest of this blog post.
What is a “program”? Let’s put it simply : “It’s a set of instructions that produce a result”. A program is what you run on your computer, phone, gaming console, or even your alarm clock. It tells the computer to do something, for example “if the user pressed the ‘up’ button, advance the minutes by one. If the time reaches this specific value, sound the alarm” (alarm clock programming) or “Draw a red circle. If the user clicks inside the circle, change the color to blue”. With many simple instructions, you end up with a complex program that can achieve a multitude of tasks, like for example Microsoft Office, or Skype. But the basic definition is that a program is “a set of instruction that produce a result”.
Now what is a “source code”? This mystical thing you keep hearing about is nothing more than “a set of instructions that produce a result”.. sounds familiar? Basically, a “source code” is the text that the programmer writes in order to tell the computer the instructions it wants the program to achieve. The source code is in itself, the program, but it’s in a readable and understandable format : a text file using a language that the programmer understands. The computer however doesn’t understand the source code, it only understand mathematics, numbers. A program’s instructions are written with “numbers” that the computer understands, for example 1 might mean “copy this” and 2 might mean “write that” and 3 might mean “show this”, etc.. (very simplistic view, but you get the idea). So the difference between a program that you run and a source code is that they are both the exact same thing, but the program you run is made up of numbers representing instructions to the computer (this is what we call the “Assembly” language or “machine code”) while the source code is the same instructions written in a more readable format, text, using a language that is easy to understand.. so instead of “1 4 185 353 532” (machine code) you would see “if the user clicks on the circle, change the color to blue” (source code).
What is a “programming language”? The source code can be written in different languages, just like spoken language, we have english, french, italian, russian, etc.. in the programming world, there are multiple different languages to define the instructions for the computer. These programming languages differ in the vocabulary (commands/functions) and in grammar (syntax). Explanation more than that is not relevant to the current topic so I’ll leave it at that.
How do you get an application (a program) from source code? It’s simple, there is a program called a “compiler” which reads this source code (the text), understands it, and rewrites it into machine code (the numbers). When you download an application, you only get these ‘numbers’ that the computer understands because that’s all you need to run your application.
2 – Open Source
So.. what is this “open source” everyone keeps talking about? Well now that you know the basics about programming, let me put it simply : a program (all those numbers) is open source, when the source code used to generate the program is publicly available.
And here is the juicy part of this blog post. Remember when I said that a program is “a set of instructions that produce a result”? Well, here’s an absolutely superb analogy: A program is like a recipe. What is a recipe? Well, isn’t it a set of instructions that you must follow in order to produce something? This analogy comes from Richard Stallman in the documentary The code (this one, not the 2011 movie) and I think it’s absolutely brilliant.
I’d like to remind people to not make the confusion, thinking that the source code is the recipe and the program is the final meal, you have to think of the programs themselves as being recipes, the ingredient is the electricity used and the result is whatever appears on your screen. The language of the recipe is what changes (from the various programming languages or to the ‘machine language’).
So now, with this analogy in mind (which I’ll keep referring to throughout this blog post), back to the question at hand. A closed source (or “proprietary”) program is like going to a restaurant where they serve this dish that you like, but when you ask the waiter/waitress what’s in it, they refuse to tell you the recipe for it. And open source is when you go to your friend’s house, you eat something that you like, and when you ask what’s in it, your friend tells you “oh, let me give you the recipe”.
Now imagine a world where no one could ever get a recipe for anything, you want to cook something, you have to relearn from scratch, experiment yourself with everything and see if the result is satisfactory, without having any references. Unfortunately, you’ll end up mixing two things together that you never should have done, and you’d be thinking how sad it is that every person in the world has to reinvent something that should be ‘common knowledge’. Thankfully, this isn’t the world we live in, and in the same way as you might enjoy cooking and exchanging recipes with your friends and family, we, programmers, enjoy sharing source code with each other, making our ‘recipes’ publicly available to everyone.
If you eat a delicious cheesecake at your friend’s house, and he/she gives you the recipe, then you try it, but then you realize it’s too sweet and you decide to decrease the amount of sugar, you have just “modified the code”, then you realize that adding a bit of lemon juice will make it better, and it does. You tell your friend about your changes, and he/she likes it and says “I’ve always wondered what it was missing”. You have just “contributed” to the program and now all your friends and family can enjoy this improved cheesecake (I love cheesecake by the way).
This is what Open Source is all about, it’s about sharing your recipes, anyone being able to improve on them and contribute his changes and slowly, thanks to the original recipe, new recipes will be born and people will enjoy more great products. It’s all thanks to this simple idea of sharing. This applies to the programming world in the same way, we write programs, we share the source code, others can improve them (add features, fix bugs, add translations, make a better/easier user interface, etc..) and everyone benefits from it.
My journey into this wonderful world started more than 10 years ago, I was using a program that I liked but I wanted something that it didn’t do. Thankfully, it was open source, so I added the feature that I wanted, gave my changes back to the project, the other users loved it which made the program more popular and some new users decided to do the same thing and improve the program, and in the end (I’ll say it again) everyone benefits from it.
3 – Hacking
What is “hacking”? Again, let’s put it simply: hacking basically means “working around a problem”. In a broader definition, it could also be viewed as “modifying something to make it do a task it wasn’t intended to do”. I have headphones and one of the wires got cut.. so I taped it and it worked.. in my definition, that counts as “hacking” because I worked around the problem. The term “hacking” has been publicized as being ‘evil’ or a bad thing, but people confuse it too much with what it really means. I hack everyday and you probably do without knowing it. Back to the food/recipe analogy. Did you ever go to someone’s home and were served a meal, then you took the salt from the table and added some to your plate? You have just “worked around a problem” (not salty enough) and you just modified something (the meal) from its intended purpose (the ‘view/taste’ of the one who cooked it). In my definition, you “hacked” the meal to make it fit more to your taste.
This is the reality of things, when you modify something that you own to make it more to your taste (everyone has different tastes after all), you are “hacking” it. When you decide that 200g of sugar is better than 250g of sugar in your cupcake recipe, you are “hacking” the recipe. But in the terms of the computer world, the term has been used widely to describe pretty much anything we do, but mostly things we do in a hurry. My friend programmed his computer to play a sound (an alarm) when his girlfriend connects on MSN so it wakes him up, but he would say “I hacked it” because he did it in 5 minutes and didn’t spend months setting up a whole infrastructure behind this “wake me up when my girlfriend is online” system. Nowadays, the simple fact of “programming” is called “hacking”, it’s nothing illegal, it’s nothing harmful, but most of the time we say “I’m hacking” rather than “I’m programming” simply because the act of programming is all about finding solutions and working around problems. You should read the definition of the term as explained in wikipedia.
The problem is that there are those who use their talent for criminal behavior and when it’s related to anything “computer-y”, people decide to call it “hacking”. It’s like saying that “cooking” is evil and anyone who “cooks” is a criminal because someone, somewhere put a drop of poison in someone else’s food. Isn’t that ridiculous? I very often see people saying “death to the hackers” or “those hackers are criminals and should rot in jail forever” without knowing what they are talking about. It’s funny how people get emotional and suddenly they become judge, jury and executioner. To all these people, let me tell you something : The next time that you add some salt to your meal, watch your back because the FBI just might lock you up for your crime!
Now here’s another thing that we, programmers and hackers, often do, it’s called “reverse engineering”, it’s basically about understanding how something works without being told by the original maker. Whenever you try to understand how something works, you are ‘reverse engineering’ it. In the recipes analogy, this would mean that when you taste something and you start wondering if there’s garlic in it, or say “is that cinnamon?”, you are basically reverse engineering the meal by trying to recreate the recipe (or part of it) by looking at the final product.
Yes, that is what reverse engineering is, you receive a finished product and you try to understand how it was made. This is equivalent to going to a restaurant and trying to make the same dish that they served without them giving you the recipe. If you ever did that, then you definitely know what a reverse engineer is.
4 – The Greedy Corporations
Now, this is the interesting part, the ‘greedy corporations’. I’m saying it like this because I didn’t want to say “Sony” because they are clearly not the only ones playing this game. Why are they greedy? because they want to have total control over you and your freedom, thus allowing them to generate more profit. I’ll go back to the recipe analogy: What Sony/Microsoft/Apple/etc.. are doing is basically the equivalent of LG selling you a kitchen appliance and saying you can only use it with their products! Imagine buying a kitchen stove that only allowed you to cook using ‘LG and Tefal” pans… or imagine a pan or a pot that only allowed you to cook food from some specific brands. No, you can’t buy the cheap, equivalent (and sometimes better) “no name” brand or buy your fresh vegetables at the market.. no, those vegetables have to have been processed by those giant corporations that put some sort of label on it allowing the pan to cook them. This is my analogy, it may sound stupid, but I believe this is what it is.
Did you ever wonder what “DRM” (Digital Rights Management) is? well to put it simply, it’s like having a microchip inside your Tefal pan, and it continuously detects what’s in it.. if you ever dare to put in the pan an ingredient (a tomato!) that wasn’t pre-selected and pre-accepted by Tefal, then the pan would automatically and instantly cool down and stop absording heat. Hell, it could even send a signal to the stove which will simply shut it down. That’s what DRM is.. and why is it there? Well, they would tell you that it’s “For your own good”, it’s because they want to deter people from stealing food from the supermarket or using products that aren’t “fresh” or up to their standards. But what it really does is that it prevents you from using your fresh vegetables that you proudly grew yourself in your backyard, so that you have to buy their product. Even worse, DRM means that you can only use ‘pre made’ cookie dough in your oven.. if you get a better cookie recipe from your friend and try to make those cookies yourself, the oven will not turn on. And for those “super awesome, elite, we are the nice guys” oven brands that tell you “wow, you can bake your own cookies! Here is the recipe!”, you have to read the fine print, the recipe says 250g of flour, and it’s unfortunate, but the oven will not turn on if you made the mistake of puttin 255g of flour in your dough. And I’m not even talking about the LG microwave that will only heat meals that were cooked on an LG appliance, or the fridge that will not cool anything without the “Kraft” label on it…
The irony is that when you buy your pan, you’re buying it for 100$, because do you think that these greedy corporations will pay the fee for the DRM? no, YOU are! The pan should cost 20$, but they are charging you 100$ because you have to pay for that microchip in your pan, you don’t want it, but you are paying for it.. you have no choice! And if someone comes along and creates a new, DRM-free pan and wants to sell it, they’ll label him a “pirate” (ouh, that’s a scary word) and pay millions in propaganda and in advertisement (that conveniently appear at the bottom of your pan and on the front glass of your oven) to tell you how this DRM-free oven/pan is ‘evil’, will eat your babies at night and will kill your dog. The funny thing is, the first time you hear it, you’re thinking “wtf?”, then after hearing it 1000 times a day, you believe in it as being the absolute truth. You will eventually get used to verifying the “compatibility list” of your new oven before you buy it.. make sure that you can borrow plates from your neighbor because they are “authorized/licensed accessories” to the oven. You will get used to checking the label on your vegetables when you go to the supermarket to make sure that they are compatible with your pan, and you will get used to not buying a specific brand because your fridge’s manufacturer never made a deal with that brand so you can’t put it in your fridge…
I know what you’re thinking : “what the hell?”. Yes, what I just said sounds absolutely absurd, it sounds crazy and it doesn’t make any sense. After all, who would accept that? Who would even think of doing some crazy things like that? Well here’s the thing, the reason I love this analogy between programming and recipes is simply because not only is it quite accurate, but it’s also something that everyone can relate to. I think pretty much everyone knows how to cook, if even just an omelette. And if you don’t, you probably saw or know someone who can. If not, then at least cooking isn’t a concept that is so “obscure” that you can’t comprehend it. If the kitchen appliances tried to force all those restrictions, or if people tried to outlaw exchanging recipes, then pretty much 99.99% of the population will say “this is bullshit, we refuse!”. But in the computer world, this is exactly what is happening, only nobody cares because nobody can understand it… all this “computer-y” stuff is not something that interests most people, so they don’t try to understand it and they don’t care about it, and for those who do, well, unfortunately, they prefer to program rather than go on trial against all the corporations.
Here’s a real life example, here is a ‘hack’ that I’ve done a couple of days ago :
This is indeed a ‘hack’, I used two tools that weren’t made to be used together in order to work around a problem that I had at that time. There’s nothing wrong with it! Both the whisk and the drill are mine, they are my property and I should be able to do what I want with them. However, if a similar situation was happening in the computer world, then I’d already be getting a lawsuit, because for some reason I don’t own the drill, I only paid to be “authorized to use it the way they allow it”. They would call me a “pirate” because I’m “killing the industry”, because by doing that hack, Black&Decker are losing money. They would be right, because since I did that hack, I didn’t have to spend another 100$ to buy an electric mixer. The funny thing is that I’d probably lose in court because there are no real laws to protect me as a consumer into using my tools any way I want, at least not in the programming world.
I read this last paragraph again and I’m thinking “I’m a lunatic” and I perfectly understand if you’re thinking the same thing. At least now we have something in common, we both think that the current situation in the programming world is completely crazy, and I’m glad you are able to see it.
5 – My angry rant
Yes, I’m angry! I am angry because I see the world evolving at an alarming rate but the laws (and people’s common sense) isn’t. I will dedicate this paragraph to rant about all the things that I recently saw and that got me angry. If you don’t want to see some angry dude raging, then skip it 🙂
First of all, there are many people who are associating us, the jailbreakers, the programmers, the hackers, with what recently happened to the PSN data leak. Because they couldn’t play their games online for a few weeks, they decide to throw their anger at us, put us all in the same boat, and label us criminals. Every time we speak, I see comments saying “ah, these criminals are now trying to justify their crime”. But.. what crime? What crime did we do that you should label us criminals? Don’t throw words like that without understanding their meaning! Or at least, use your common sense before thinking that anything deemed ‘illegal’ is a ‘crime’! Do you know that in France, a woman must wear a dress, and that, by law, she’s a criminal if she wears pants/jeans? It’s an old law when only men wore pants and a women who did was considered a ‘transvestite’… this is a stupid example, but I’m using it to show you that common sense should overcome stupid laws.
If you think we’re criminals for jailbreaking the PS3, then how is it a crime to want to use your backyard-grown tomatoes to cook your meals? If it’s because of the PSN hack, then here’s another analogy for you: when you go to a restaurant and someone orders food, eats it and runs without paying the bill, how would you feel if the restaurant’s owner puts all the blame on you, you, who were sitting all the way to the other side of the restaurant, who didn’t even see or notice the thief, but you had the audacity of adding a bit of ketchup to your burger. As you know.. you “modified the vision of the chef” and that is a huge criminal offense and you should rot in jail you filthy criminal. No need to answer me, but just think about it.. how would you feel? (and yes, I believe that this analogy is very representative of the situation).
Now here’s another thing that makes us criminals: reverse engineering. We are ‘criminals’ because we reverse engineer products? Back to the recipe analogy: the next time you taste a meal and say or even think “humm, I think they put garlic in it”, then consider yourself a criminal and you should rot in jail.
If one million PS3 users (I’m being generous) told Sony that they don’t agree with them, that would still only be 1% or 2% of their user base, so they keep doing what they’re doing because 1 million people is an “insignificant number”. What happened last year when Sony removed OtherOS support from the PS3 is the equivalent of Frigidaire selling you a fridge then a couple of months later, tell you that “On the 1st of april, your freezer will stop working, we suggest you remove any food from the freezer and stop using it. You have a choice though, if you don’t want your freezer to automatically stop working, then empty the top 2 shelves of your fridge because those sections in the fridge will be at room temperature now. If you ever put something back into the top shelves of your fridge, then the freezer will be disabled permanently”… sure we have a choice, thank you for your generosity!!! The worst thing, the most heartbreaking thing is that going to Frigidaire’s website to complain about their unlawful practice, you find those thousands of people cheering and saying “who cares? it’s A FRIDGE, it’s not a freezer!! who uses the freezer anyway? just buy a dedicated freezer instead!” or “I wasn’t using the freezer, after all it does say “refrigirator” on the machine, so that freezer was a BONUS, be happy you got to use it for free all this time”, etc.. Let me ask you a question… if you accept that Sony removes OtherOS from your PS3, then you will have absolutely no problem in Frigidaire disabling your freezer right? even if you don’t use it, I might but who cares right? you’re not egotistical after all, if you don’t use it then no one in the world is? And again “DEATH TO THOSE DAMN HACKERS”.. how dare they put a cheesecake in the fridge when Frigidaire specifically said “no pastries”!! After all, they clearly wrote it in page 258 of their user manual!!!! After all, it’s Frigidaire’s fridge (no you didn’t buy it, you only ‘rented’ it for 2000$, it’s clearly written on page 531 of the manual!) and they have all the rights to it, they have all the rights to defend their interests… I mean, they never made any sort of deal with the bakeries!!! You know what this “deal” means? it means that the bakeries had to accept paying Frigidaire to allow their pastries in the freezer, so every time you buy something from them, you are paying 50% to the bakery and 50% to Frigidaire, and this allows you to put your cheesecake in the fridge and you’ve always been wondering why the prices doubled recently..
Anyways, you get the idea… but what pisses me off the most is how all these people think that their mission on earth is to defend Sony… like they say where I come from “is it your father’s company?”… seriously, why do you feel the need to go all over the internet, in every forum that you find and yell hate messages against ‘us’? why do you feel like you need to repeat Sony’s propaganda everywhere and why do you hope that we die and/or spend our life in jail? What do YOU gain from that? Why do you think that this multi-billion dollar company needs you to defend it? It’s like walking in the street at night and seeing a mob of 10+ huge guys beating an innocent child in an alley and you’re rooting for the mob… where is your common sense?
6 – Conclusion
I wrote this post because I wanted to make people understand our world a bit better. I know that some people might disagree with some of the things I said, but remember, this is not meant to be an exhaustive explanation of how computers work but rather simply a glimpse into it, in terms that non-initiated people can, hopefully, understand.
I hope that I have achieved my goal: make a few people understand us and most importantly, make a few more people think about these issues. I know that I will continue to see misinformed posts everywhere, and nothing can change that, but to those who are willing to listen to others and accept differing views, then I’m glad I could help you with that (if I did). If you have questions or want to start a debate on something I said, feel free to comment.
And for your information, I am not saying that closed source is evil, I believe in freedom, and if you want to keep your code closed, then you are free to do so. I also do understand the need for closed source sometimes, in order to stay competitive for example, but I think that if everything was open source, then competition would become different. I simply believe that the world would be a better place if everything was always shared. Knowledge is for everyone, and I just can’t imagine where the world would be today if people shared all their ideas/code/recipes/etc.. with each other. It would certainly be a wonderful world. I find it truly pathetic to know that every company is recreating the same thing that others did before them.
Finally, I’d like to point people to the EFF, the Electronic Frontier Foundation. It’s a group that protects us and defends our digital rights every day. Right now, we are still under the mercy of the giant greedy corporations, but thanks to the EFF’s efforts, I hope that some day soon, we will be free to code the way we want, just like we are free to cook the way we want.
Thank you for reading!
Update: After reading a few comments about this post, I thought I should clarify a few things.
First of all, this post isn’t about Sony or the PS3, which is why my title and fourth paragraph says “Greedy corporations”. While I do address the PS3 subject in my rant, it is only because it’s a subject that is dear to me and for which I have a lot to say. But what I outline is and should be considered generic and the main purpose remains to “open a window into our world” for those who are not computer savvy and who may not understand the issues at hand. I want people to understand that, from our point of view, the world is a crazy place, and you can draw parallels with many things, not just with the recent issues with Sony.
Also, like I’ve found myself saying a few times in the comments, there’s a saying that should govern us all : “One’s freedom stops where someone else’s freedom starts”. I believe that you are free to do whatever you want. As a consumer, you should be free to use your legally bought devices any way you wish (as long as you don’t infringe on other’s freedom, whether it is other’s freedom to gain money from their work or freedom of a fellow customer to enjoy their product (online cheating as an example)), but also, as a product manufacturer or a company, you are free to put the restrictions you want and you are entitled to use anything you feel is needed to protect your investment, but again, as long as it doesn’t infringe on other’s freedom.
I’ve had a few comments about DRM, but I never said that DRM is bad and this post isn’t at all about DRM. I have personally no issues with DRM as long as it’s reasonable but when you think that your own needs are more important than the needs of others, that’s where I see a problem. If I ever got an idea for something that could potentially make me rich, I would pursue it and I probably would try to protect my investment and intellectual property as much as I can, but there is a moral barrier that remains and I will never allow myself to be controlled by greed in such a way that I would sacrifice other’s freedom to further my goals.
In the same way, you are free to do whatever you want with your work, I have absolutely no problem with closed source applications, I simply prefer open source and I believe that the world would be a much better place and our civilization would be much more advanced if everything was open source.
One example of the above is the fact that advertisement exist as a sort of ‘payment’ for things you watch. When I watch a movie on public TV, I see ads and that’s what’s paying for the movies I’m watching “for free”, but then, why is it that when I buy a DVD, I am forced to watch ads before accessing its content? Didn’t I already pay for the DVD so why are you forcing me to watch ads? And even if you put ads in there, and it’s ok, then why can’t I skip them? If I watched the movie 10 times, do I still need to see the same ads? And why would I be forced to watch a trailer for a movie that I might have already bought (or which I already saw and hated)? Why is it that if a friend comes over and I want to show him a 30 second scene from a movie, do I need to wait 10 minutes until all your trailers finish just to show him that? This “you cannot skip the trailers in a DVD” is something unrelated to DRM but is still something caused by companies’ greed (get more money from each sale) which is infringing on my freedom of using the DVD I legally bought the way I want (in this case, watch it without having to suffer through all those trailers).
Finally, this post contains information, it contains knowledge, and my belief is that knowledge should be free and available to all. I am not trying to generate any page views (my poor server would hate me) and I don’t have any ads on my blog, so if anyone wants to publish this whole article somewhere else, where others could benefit from its content, then you are permitted and encouraged to do so. I’d be quite happy to see this published in its entirety on sites such as Arstechnica, Kotaku, Joystiq, the New York Times, or whatever other media that would reach more people than this humble blog.
Don’t forget, share, and everyone benefits from it 🙂
Finally, after almost 2 months of hard work, I’m proud and happy to announce the release of the Homebrew game I’ve been working on : SGT Puzzles. It’s a collection of portable puzzle games for Windows, Mac, Linux, Android, PocketPC, Android, etc.. and I’ve ported it to the PS3 too!
The release of this homebrew game comes with the release of The Humble Homebrew Collection which is inspired by the Humble Indie Bundle Initiative (but not endorsed by it). The difference here is that you don’t have to pay anything in order to enjoy the games, they are free to download by anyone, but you are also able to donate any amount to the developer of the puzzle games (Simon Tatham) as well as the PS3 port developer (me!) and the EFF. You decide who to send the money to just like with the Humble Bundle. I’ve also linked to the game’s Windows, Mac and Android ports if you want them (they are already available in most Linux distributions).
The addition here and probably the most important part is a petition where yo get to sign and send a message to Sony asking for a legitimate way of having homebrew games on the PS3. Every signature will send an email to SCEE, SCEA, SCE Australia, SCE New Zealand and Kazuo Hirai, the CEO of Sony Computer Entertainment. This is done in the hopes that Sony will finally see the light, learn from the mistakes they’ve been doing these past few years, and finally give us a legitimate and officially supported way of developing homebrew applications for our PS3 Systems.
Sony would be stupid not to answer to that, considering that Apple complied, Microsoft complied and Google complied, and they are all generating huge revenues thanks to homebrewers, with zero investment from their part. I know that the Sony execs only understand when you talk about money, so I hope this is a good enough incentive for them. Clearly, they do not care about their customers, so I don’t think they’ll change anything only to do what is right.
The SGT Puzzles game includes 33 puzzles, which are excellent for the most part. My favorite is and always will be Pattern, as I’ve spent countless hours playing it. I’ve recently also discovered Rectangles and Net which are also very good (in higher difficulties). I suggest you give those puzzles a try. Above all, I hope everyone can enjoy these games.
This all started about 2 months ago when I found a copy of Pattern on my PC and started playing it again. I tweeted about it and asked if someone wanted to port it to the PS3. Clement Bouvet (@TeToNN) quickly made a proof of concept using cairo. That got me excited and I decided to help him. We ended up writing a PS3 application over Simon Tatham’s Portable Puzzle Collection which, I must say, is very well written and made porting it to the PS3 very easy. It took maybe a day or two and the first game was playable on the PS3. At that point, I discovered the Cairo Drawing API which I loved and and I decided to invest myself entirely in this. It took 3 more weeks of hard work to get the whole system working (choose your puzzle game, change difficulty (Select) and writing the whole menu system for the game). I’ve received various help, Surenix made the designs for the menu graphics and buttons, and BeGamer helped design the HHC website.
The game still lacks a few things, and I will continue to work on it and improve it so everyone can enjoy a quality homebrew game, that, I hope, will make the anti-homebrew purists jealous.
The funny thing is that since day one, the source code for this game was available on my github account, but no one noticed it. Only a few people who accidently ended up on my github page found it, but no news website author found it or reported on it. I’m glad, because it allowed me to make this happen the way I wanted it to and launch this HHC initiative when it became ready. I’d like to ask the various websites out there not to link directly to the games (even if you are allowed to) and instead link to humblehomebrew.com so people can sign the petition while downloading.
Most of the code is licensed under the MIT license. Parts of the code (the cairo menu system) is licensed under the LGPL license and I plan on extracting that into its own library for other developers to use in their applications.
The website took about 3 weeks to code. I learned two valuable lessons.. first, HTML coding is crap… secondly, it’s much more complicated than it looks. I hope people will appreciate this effort and I hope the Humble Homebrew Collection will make a difference.
In the future, I hope to enhance it by adding new homebrew games whenever I find something of quality, and keep the website and this whole initiative going for a long time, for as long as necessary.
So.. go ahead, download the games, sign the petition, maybe donate if you’re feeling generous, and most importantly, have fun!
It’s been a while since my last post! A lot has been happening lately, I’ve mostly kept my followers updated on what’s new through my Twitter account, but I think that this deserves a post of its own!
I’ve been reversing some PPC code in IDA and unfortunately, it doesn’t handle the PS3 files very well, so I wrote a lot of scripts in order to make it parse the files properly! There was one thing missing though that I couldn’t do with an .idc script : handling of jump tables.
Yesterday, I took on the task of writing an IDA plugin in order to parse the ppc code and find jump tables and define them in IDA’s kernel so the analysis is done properly! It was a very fun and exciting challenge that I enjoyed doing, and I’m happy to say that I succeeded and it works very well (on the files I tried anyways).
The IDA API is extensive and easy to use, and allows you to do pretty much anything! I also found the IDA Pro Book to be extremely well written and very useful! I would suggest to anyone who likes tinkering to try and write an IDA plugin, because it was a challenging but fun experience!
I initially wrote the plugin thinking that the jump table instruction patterns was always the same, but when I started testing, I found out that some instructions could have a different order, there might be inserted instructions in the middle of the pattern, or different registers being used, etc.. so I eventually had to rewrite my plugin and ended up using a class that comes from IDA’s SDK which takes care of “instruction rescheduling” and “intermingling of the jump sequence with other instructions”, at least I learned from my first try and it made my second try a lot easier. I also realized that I haven’t done any C++ in maybe 5 or 6 years, and I really forgot all about how to write C++ code. It was a bit embarassing to google “how to derive from a class in C++”, lol!
Anyways, I am now releasing my scripts and my PPCJT plugin for IDA under a new project : PS3IDA.
I’ve created the ps3ida repository on git-hacks.com (Thanks again to @dashhacks for providing us with this safe haven for all our legal tools). The repository contains many files, I suggest you read the README file for a description of each, but the most important ones are analyze_self.idc and analyze_sprx.idc. I’ve also ported my lv2_dump_analyzer.idc script to work with IDA 6.0.
There are two plugins in ps3ida, the first one is the well known PPCAltivec released by xorloser, I’ve decided to add it to the project so the source code stays available for anyone who needs it. I also slightly modified the source code so it compiles correctly on Linux using gcc 4.x. The second plugin is PPCJT that I wrote yesterday, it will find jump tables and define them in IDA’s kernel so the functions get properly analyzed. Just install it, and when you see a switch/case in the code, put the cursor on the ‘bctr’ instruction and press ‘C’ so it can parse the jump sequence and fix it, or just go to “Options->General->Analysis->Reanalyze program” and it will fix them for all the file.
I have built the PPCJT plugin for Windows and Linux for IDA v6.0, you can download it here.
My personal suggestion, since IDA could screw up the analysis in its initial run, would be to completely undefine the file (Ctrl-PageUp + Alt-L + Ctrl-PageDown + U), then run the analyze_self.idc or analyze_sprx.idc.. it will take some time, but then you’ll get a beautiful file loaded 🙂 Especially with the correctly named imports, this should help a lot any reverse engineer out there!
p.s: If you have no idea what I’m talking about, then this is not for you, this does not lead to any ‘CFW’ or jailbreaking of 3.60 or whatever else you might hope for… so don’t come here and post stupid and/or irrelevant questions of that kind… please do not comment if you’re not a user of IDA or if you don’t know what IDA is or if you don’t have anything constructive to say.