To better clarify my generic question:
I have gotten the Android emulator to work by running a full "make full-eng" build, as per the Google documentation. However, I wanted to debug it, so once I ran the emulator, and called "$ adb shell dmesg" and routed that to an output text file, I found a couple of strange lines:
...
<4>goldfish_new_pdev goldfish_interrupt_controller at ff000000 irq -1
<4>goldfish_new_pdev goldfish_device_bus at ff001000 irq 1
<4>goldfish_new_pdev goldfish_timer at ff003000 irq 3
<4>goldfish_new_pdev goldfish_rtc at ff01000
So when you run the Android full build, it gives you Goldfish as the system image? I want to know if it's testing the things I want for Galaxy Nexus. The kernel was a modified maguro kernel (omap project) for Galaxy Nexus, that I put into the build tree. But the platform I want to be testing is IceCreamSandwich. Is the emulator testing this platform? (b/c the output in this log is leading me to believe it isn't) Or is the emulator testing a "generic" image?
Also, an important further question: I modified the kernel's "socket.h" file, to override the INET protocol with an undefined protocol (FINS). In theory the phone should boot up, but NO internet access. Does the phone emulator care what you do to the internet protocols? Does it use your host computer's networking capabilities?
One further follow-up: What processes/system-services/events (that are involved in booting to a stable state) of the phone DEPEND on the internet protocols of the traditional underlying network stack? (protocols being defined to set up the network sockets)
At the time I wrote the question I did not understand a few things and think I've learned a little while messing with the emulator at the "kernel level". First of all, the emulator tests the "goldfish kernel" (Linux version 2.6.29, with ARM architecture) of a "generic" phone brand. It's almost as if the emulator is a type of phone in of itself, and you cannot mix these image kernels. For example, I tried building a Nexus S crespo phone image with goldfish kernel (so in other words, no crespo kernel) and the phone just "hangs" at the Google splash-screen (at least it's not a boot-loop).
My research (FINS) worked on this emulator, but did not work on any of the 3 platforms supported on actual hardware: Nexus S, Galaxy Nexus, and Motorola Xoom. I am not sure why, given Google does not seems to give users the ability to debug at the lowest level of a phone (I'm sure the actual developers use such kinds of tools in building these phones/testing them). This leads to one major issue which answers my last follow-up: The Android Debug Bridge depends upon INET protocol. My emulator boots up successfully and runs as I want (no internet, b/c there is no INET), but these actual phones do NOT. My hypothesis is that: If INET is overridden with a protocol that is empty (in this case, that would be FINS, which intends to deal with INET at the userspace level, but this appears to be too late for the phone system to be satisfied), the ADB daemon (classified as a type of system service perhaps) cannot work/be connected to and Android hardware will crash because of this. The emulator I believe is more flexible than a real phone, as the hardware is perhaps virtually represented and does not have the same limitations as physical hardware does.
You can consult my wiki/documentation (part of my research team's larger site) of my struggle with the Android phone boot process for more details and my various attempts: http://finsframework.org/mediawiki/index.php/Alexander_G._Ororbia_II
If anyone ever figures out how to get a working boot log from a Nexus S, Galaxy Nexus, or Motorola Xoom that gets stuck in a "boot-loop" (without ADB), please let let me know, as I will be working on this problem for a while to come (and I will update my other Stack Overflow-Android questions to reflect this correction). Any corrections to my understanding would also be appreciated.
NOTE: This answer is editable, as I still think there is some way of getting the phone to produce boot logs on the host machine without the ADB daemon.
Related
Im developing an uwp app on Raspberry Pi 3 with Windows IOT Core. But after I deploy my app and use it for couple days the os crashes. It says something went wrong. It says "Your pc ran into a problem and needs to restart". It restarts couple times but still same error on every boot.
I tried to remove the sd card(Class 10,64 GB) format it and reinstall everything. At first it was okay but after some time same error appears.
I tried to use different os builds and it didnt work.
I tried to use industrial power supply (5V3A) and also it didnt work.
My SD Card is not one of the recommended ones but do I really have to get the recommended sd cards to use the windows iot core properly?
"Your PC ran into a problem and needs to restart" is a typical blue screen message seen on Windows systems from the last few years - laptops and desktops with far larger hard drives and no SD card. The error is not associated with a RAM or disk space shortage (operating systems running in graphical mode usually monitor and actively warn about either). In your case, it is showing at startup, when not much is running (taking up RAM), and you can check the amount of space used on the card with the PC.
The key stats for SD cards are size (you have plenty) and speed (clearly enough or you would have trouble installing/running anything after starting the Pi). The cause is something else, and finding out what will require getting a more detailed error message from Windows - "a problem" could mean anything. In my experience, blue screen errors have mostly involved having a wrong driver installed, sometimes a bad Windows update - but IoT Core has its own alternatives, like "bad system configuration". Look for the underscored string (e.g., BAD_SYSTEM_CONFIG_INFO) at the end of your blue screen message, as that is the first hint.
Unfortunately, most Windows BSoD documentation is for traditional PCs, so I cannot recommend specific troubleshooting tools and be sure that they will run on the Pi.
You can use Windows Debugger to debug the kernel and drivers on Windows IoT Core. WinDbg is a very powerful debugger that most Windows developers are familiar with. Or you can also refer to this topic in MSDN, it shows how to create the dump file when the app crashes. If possible, you can share your code so that we can reproduce the issue.
My employer has asked me to prepare for testing several thousand Chromebooks (mix of models/manufacturers) to refurb/flip. This may be a recurring thing.
Most or all of these will be old enough that CCD will not be available. I'd like to connect a widget such as a Raspberry Pi to the USB and have it automate testing as much as possible.
I know I can use keyboard emulation to inject commands, but I'd like to get a crosh session running over USB so that I can read info from the DUT besides just controlling it.
Google shows bazillions of returns about using a Chromebook as an ssh terminal but what I'm looking for is the opposite. I'm prepared for the answer to be a simple "no" but I'm concerned because I can't find that anyone else has asked this question. I don't think I'm that creative, so I suspect my Goog-fu is weak.
The answer appears to be "no". However I solved it another way; using "gadget mode" I have a Raspberry Pi ZW enumerate as a keyboard and a serial port. I put the Chromebook into Developer mode, open a developer shell with ctrl/alt/F2, or on a PC/linux or Mac system open a terminal window and type "sudo su" (these have to be done manually). Then I have the RPi issue this bash command to identify the serial port "in the blind":
SERPORT=/dev/serial/by-id/$(ls /dev/serial/by-id) # Chromebook or PC/linux
(or)
SERPORT=$(ls /dev/cu.usbmodem*) # Mac
Now I can have the RPi inject commands via the keyboard, put ">$SERPORT" on the end of each command, and the output comes in the RPi gadget serial port. The RPi then packages the data and forwards it over WiFi to our CRM. It's working nicely for Chromebooks, PCs booted into linux, Mac desktops and Macbooks.
Edit:
The company I work for has actually turned this into a product and so I'm not sure how much detail I should share, but...
I learned my way around gadget mode on the RPi from this link. There are examples for setting up a keyboard and a serial port. Using the templates in that link, I made a device called /dev/hidg0 which emits keyboard scancodes from the RPi to the Chromebook. I also made a device called /dev/ttyGS0 which the Chromebook sees as a serial port.
So I send keystrokes with some python like:
with open("/dev/hidg0","bw") as hid:
hid.write(blah)
and then have the Chromebook send text to the serial port, which I then read by looking at /dev/ttyGS0
Hopefully this will be enough to get you started. I found the isticktoit link very helpful.
I have done a jailbreak on old iPad 1, using redsn0w. Has worked really well. Installed OpenSSH, and I can use Putty on Windows or SSH on Linux to login to my iPad, and of course, pscp or scp to migrate files to/from using Windows or Linux. Installed DOSbox (using DOSpad.deb file), and it works fine. But there was no "ping" on the basic jailbreak version, so I installed "inetutils", which provides all the GNU inet stuff (ping, ftp, inetd, rlogin, telnet) and then found "arp iconfig netstat route traceroute" in Network Commands. This makes an old tablet very, very useful. Really fine stuff, but I notice now that the iPad network access times out quickly. This is new behaviour, since the Cydia "inetutils" install. If I set the iPad down, after a few minutes, I cannot ping it from any machine on my LAN. I could, before I installed the networking utilities. Maybe a security feature? If so, can I back out the network stuff, and just have ssh access, and have it not timeout? I want to to be "alive" all the time.
Ok, found it. When you jailbreak an iPad ver. 1, running iOS 5.1.1, using Redsn0w, the initial install of the code that provides root access does not include standard inetutils. The original behaviour of the iPad 1, if configured with static ip values, meant that if was on, and the wifi was enabled, it would respond to a "ping", even if the screen was "asleep".
This ping-response was useful for diagnostic purposes. Initial install of the jailbreak code did not change this behaviour. But I could not "ping" out from the iPad to other machines since there was no ping.exe available, even after the jailbreak (this contrasts to Blackberry Playbooks, which had a "ping" utility, and would also respond to pings, even if "asleep").
So I downloaded the "inetutils" package from Cydia source Telesphoreo, and that provide a ping.exe, which could be used in console mode on the iPad. It worked fine, and is a very useful program.
But, if you set the iPad aside, after about 5 minutes, it would time out. It appears the wifi transmit function is just shutdown, and response to "ping" is explicitly disabled.
After much research and experiment, I've determined that you can re-activate the iPad "ping" response - remotely - by sending it an SSH query. Example:
[your_id#Linbox ~]$ ssh mobile#xxx.yyy.zzz.aaa
where xxx.yyy.zzz.aaa is your IPV4 address,
assuming you have configured your iPad with a static ip value. (I own a couple of class C ip ranges, so I have been using these for many years, in my work). The two defined userids after jailbreak are "mobile" and "root".
The new behaviour appears after you download and install all the newer "inetutils" utilities, and the "Network Commands" utilities, from the Telesphoreo source repository.
This behaviour change is actually a pretty good idea, as it discourages inappropriate usage of ping, and probably also saves battery life. But it is a change from previous operational characteristic. Another fellow went down this same rabbit-hole, and documented the solution on the "jailbreakqa.com" site, url below:
http://www.jailbreakqa.com/questions/192379/persistent-wi-fi-when-locked
Hope this info is useful.
Curious to see this query downvoted.. Lemmie say, having this old iPad run as a full-blown remote-accessable Linux box is very useful. Once jailbroken, one can scp files back and forth, install custom computational code locally, and basically have all your office on a small, thin, light tablet in a little briefcase. Most useful.
Very interesting post... just what i am looking for. I use an ipad 1/16g/3G for a display on my kitchen wall for displaying domotica info. This works well and using ssh i can have it turn on, display something and turn off.
I got myself another ipad 1/16gb wifi only and this one had the sleeping wifi problem. My first thought was that it had to do with the 3g chip.. that maybe this keeps the ipad alive while the other one goes to sleep. The 3G model doesn't have inetutils installed and still doesnt go to sleep. So there seems some merrit to my line of thoughts.
I installed the inetutils on the wifi only ipad and it seems like this solved this trick. I can ssh into it just fine.. even when it is in sleep mode. Thanks for your update.
The link in your post doesn't work anymore..
I need to slow down (simulate bad) internet connection, I found some documentation where it was achieved by "ipfw pipe" command , the thing is that in latest MAC OS versions , ipfw was deprecated (and removed)...
I was wondering if there are any alternative to the ipfw API ?
Does anyone know how latest Network Link Conditioner achieves it?
The original previous way which enabled to slow down an internet connection :
sudo ipfw pipe 1 config bw 56Kbit/s delay 200 plr 0.2
and to clear the pipe :
sudo ipfw delete 1
Thanks.
I don't know much about Mac OS (I use Linux myself), but I'll give this a shot.
A bunch of digging established that ipfw seems unavailable, as you say.
I was also unable to find a way to use the Network Link Conditioner from the command line. Everything should be usable from the command line, so that's stupid.
One work around would be to try to access the NLC from within AppleScript. The following will get you started on toggling the NLC:
property thePane : "com.apple.Network-Link-Conditioner"
tell application "System Preferences"
activate
set the current pane to pane id thePane
--delay 2
end tell
---
tell application "System Events"
tell application process "System Preferences"
try
click ((checkboxes of window "Network Link Conditioner") whose description is "enable switch")
on error
click ((checkboxes of window "Network Link Conditioner") whose description is "enable switch")
end try
end tell
end tell
I think that you can run a script from the terminal with osascript <SCRIPT>.
As an alternative, Charles Proxy is a pay-to-use program that can be used to perform throttling, provided you can convince the software you are testing to connect to the proxy's port rather than directly to the internet. Maybe there are free proxy solutions out there somewhere?
Perhaps Squid would work in that regard. SquidMan seems to be an easy-ish way to install it for Mac. It looks as though DelayPools and or Client Bandwidth Limits might be useful for simulating a low speed connection, though I can't find evidence of people having used them for such.
I found several solutions that might work. They come from some old threads, but they might help:
How to simulate slow internet connections on the mac
Apple has made a very handy official tool to slow down the network connections on you Mac for testing purposes.
The Network Link Conditioner preference is a free download from within Xcode (for Lion and later OS). Additionally, iOS has similar function accessible from within Xcode and iOS 6 or later.
How do I simulate a bad Wi-Fi connection on my iPad?
There are a few ways you can do this, depending on your situation:
Move further away from your router. While this may seem a bit obvious, I realize that it isn't always possible while testing/debugging (for example, if you are working on a desktop computer).
Put aluminum foil around the router and/or antenna. This will (partially) block some or all of the radio signals by creating a makeshift Faraday cage. The results you get will depend on the strength of your router signal, distance from the router, and other environmental factors.
Set your router's wireless signal power to a lower setting. The method for doing this is different for each router, so you will have to look at the user guide for instructions on how to do this.
Slow down internet for iOS simulator
You can set the network to slow characteristic by testing on devices. Go to Settings -> Developer Settings -> Network Link Conditioner -> Enable. This is for iPhone/iPad running iOS 6
I don't know if the last one you can still do.
I've used many methods in the past for slowing down network connections, among them:
performing a parallel download of some massive Linux ISO file;
physically pulling out the Ethernet cable (at one point, I actually toyed with the idea of building a push-button device that would sit between two cat5 cables and do this without having to physically disconnect the whole cable).
using ifconfig eth0 down ; sleep 1 ; ifconfig eth0 up.
Hopefully one or more of those methods will help.
If you're looking to slow down your network connection because you're doing testing/profiling work, one option is to get a specific device that can create network latency/noise.
For example Apposite Tech's mini2 WAN emulator allows you to change values for bandwidth and packet loss. You can roll your own device too using something like: http://wanem.sourceforge.net/ . It just depends on your needs, time and budget.
I’m doing a study project on wifi signal quality. What I want to do is use Raspberry Pi’s to monitor as many metrics as possible on packet level data. I want to do this by putting wifi adapters on monitor mode (using airmon-ng) and than capture the data about the packets using a wireless network protocol analyzer, like tshark.
What I understand from the wireless networks is that you mainly have three parts: a frame part that has the same information independent of what you’re capturing on, which contains things as frame number, frame length and arrival time. (Want to upload images but don't have 10 reputation yet...).
Then the IEEE 802.11 data which contains the necessary stuff for the network to work. When capturing on WLAN this contains the MAC addresses.
And than we have the radiotap header, which contains all kind of information (signal strength db and dbm, noise level, signal quality, TX value, and much more). This one is a bit different, since this information is actually filled or injected by the wifi adapter you use to capture the data with.
In the present flags you can find which values are actually being injected by the wifi adapter. Now my problem is that for my research I really need as much values as possible. I’ve been working for hours but I didn’t succeed in finding a way to capture with anything more than dmb signal strength (if even available). So this is what I tried so far:
The adapters I used so far are the Edimax EW7811UN, the AirPcap Classic, the AirPcap Tx and two similar alfa adapters with Atheros AR9271 chipset. The AR9271 adapters worked out of the box on raspbian (debian for raspberry pi) on the ath9k_htc driver. Putting them on monitor mode and capturing works fine, but only dbm singal strength is given (as in the screenshots above) in the capture. The Edimax was working out of the box on the 8192cu driver, however it clearly doesn’t support monitor mode. I could put it into monitor mode when booting it on the zd1211rw driver but that didn’t even give the dbm signal strength. Strange thing however, is that a friend tried the exact same Edimax adapter and he could capture, and the only difference we could find is that the lsmod says rtl8192cu and not 8192cu. Strangely, forums are saying that 8192cu is the newer version, however this friend had the newest arch linux kernel installed (newer than the raspbian). So I installed Arch Linux on the pi, but still wasn’t able to put the edimax on 8192cu driver in monitor mode. Then I found a package in the aur repos: dkms-8192cu which was supposed to have a patched version. However, after installing it still didn’t work. Also downloading the driver from the realtek website didn’t work. There is some stuff on patching on the aircrack-ng website, but it actually is mentioning injection of frames and doesn’t really look to be what I exactly need.
Than I bought the Airpcap Classic and the Airpcap Tx to see what they could do. First of all, they have zero linux support so that already is a big drawback since l need to use it from the Pi’s. However even in windows the airpcap’s only capture db and dbm noise and signal quality. It does receive some data at dbm noise level, but it’s worthless since it is always at -100 level. I can boot the Airpcap classic and tx have zd1211B chipset so I can boot them on zd1211rw driver but this also gives no dbm signal value or anything else.
So my question is, what exactly determines what’s in the radiotap header? I guess it would be all in the driver, but I need to be exactly sure before I write off every ath9_htc driver based adapter. I’m about to purchase another adapter which runs on carl9170 driver, however I can’t find no guarantee anywhere that it will give me those values. What I did find in the literature is that the madwifi driver gives (or was giving) noise levels, however it is acquired by Atheros so the project stopped and all websites are suggestion just to use ath9k or ath5k drivers. I tried to install it but I failed because it seems to be really outdate software since the project stopped.
It would be of really big help if someone can explain me what exactly determines what’s inside the radiotap headers, and also if someone could share any experience on when they did capture more than only dbm signal strength values from linux.