Programming :: Passing Data From Interrupt Handler Function To Tasklet Function?
May 18, 2010
I am doing some Linux kernel programming for my research project. I need to record the timestamp (by using cpuid and rdtsc) when an interrupt handler (top half) is first invoked. Due to the time critical nature of the problem itself, I have to do the timestamping inside the interrupt handler itself (the first operation when the handler is called). However, I understand that tasks that are not so time critical should be deferred to a tasklet function (bottom half) for processing because other interrupts are disabled in a (top-half) interrupt handler. I am currently out of idea on how I can pass the timestamp information that I have obtained in the interrupt handler to the corresponding tasklet function.
locking mutex (phtread_t type) in a signal handler function (installed by function signal()) for Linux. It seems that if the mutex has been previously locked by another thread outside the signal handler function and then the signal handler function tries to lock it, the whole process hangs.
I am trying to pass an array to thread program. Its printing the val[0] value but its not printing value at val[1]. Can somebody help me with this problem.
I am using Debian linux. I have 100 timers running. If a timer expired which will generate a signal and it was mapped to a same function handler. All the timers are mapped to one function handler. The problem is if the timer expires one at a time, the function handler called at a time. But if the 2 timers expires at a time, the function handler is called one time only instead 2 times. Is it possible to invoke the function handler as many times based on timer expirary happens simultaneoulsy?
I am using read() in c++ to get data from a serial port. However, if no data is available on the serial port the function blocks until dta arrives.Example code:
I have written a Linux kernel module (in Linux 2.4, Red Hat 9) which does the followings: It takes srcIP, sourceport, destIP, destport and loadvalue as command line arguments. If configured load value is greater than 1, it creates different channels (i.e. No of UDP channels created equals to configured load value), assign different source port and destination port to different channels and send UDP datagram in different channels. Say for example the configured parameters are as follows srcIP=10.17.17.43 destIP= 10.17.17.44 sourceport=10000 destport= 20000 loadvalue=2.
Then it creates two UDP different channels and transmits UDP packets (in every 20 milliseconds) to destination IP address (i.e., 10.17.17.44) with source port 10000, destination port 20000 in one channel and source port 10002, destination port 20000 in another channel. When I configure to pass ?loadvalue=500? and run the module, I get the below kernel panic message in system log file (i.e., var/log/messages) 0>Kernel panic: Aiee, killing interrupt handler! In interrupt handler - not syncing. Running the same linux kernel module ,in 1000 loadvalue, I get this message, eth0: Out-of-sync dirty pointer, 49937 vs. 49954 in text console. I am unable to catch the root cause of these problems and how will I solve these?
I looked on the net for such function or example and didin't find anything, thus after having made one i guess it would be legitimate to drop it to see what others thinks of it.
#!/bin/bash addelementtoarray() { local arrayname=$1
Problem: I need a method to maintain the $i variable. In fact, actually, this variable get lost when executed. I think that an escape can preserve this variable and permit its execution inside the function, but I've no idea about.
I bought a multifunction stylus sx218 Espon model and I can not run the scanner function. I did some research and found a few solutions and very functional. I hope someone solves the problem. My version of openSUSE 11.2.
I'm currently using OpenSuse 11.1 web server. This is bad since 11.1 is no longer supported. the reason why I am using it is because Function set_magic_quotes_runtime() was no longer being used. (so I was told)
That being said, is there a way to get Function set_magic_quotes_runtime() to function on the newer versions of OpenSuSE?
the function terminates if no key is pressed for 10 consecutive seconds. I tried using the -t option as suggested in some forums, but my version of showkey doesn't have the option of changing the timeout. The options I get are:
-h --helpdisplay this help text -a --asciidisplay the decimal/octal/hex values of the keys -s --scancodesdisplay only the raw scan-codes -k --keycodesdisplay only the interpreted keycodes (default).
Is it possible to write a script to use this function and still keep the function active until an interrupt is recieved?
Assume: 1) Multi-cpu environment 2) Process that gets interrupted, is the same process that executes the interrupt handler, so I guess technically nothing gets interrupted except what the process was doing before, but it is still executing as it is executing the handler. 3) There is no top or bottom half, when an interrupt takes place the handler is invoked, executes, then return from interrupt, simple as that.
Why would sleeping the handler (puts in sleep queue, context switch to next runnable process) be a bad idea?
Now i have a problem.I want to used a hid usb device under linux 2.6.11.But i can't know how to used ioctl function to send and receive data to a hid device
I'm trying to work out the best way to achieve the following.
1)php page that grabs data from a local database. (not a problem)
2)It then needs to send this data to a c program/service running on a remote server. (I probably need it to be able to handle 4+ million reocrds in an array)
3) The c service then needs to process the data and send it back to the initial php script that called it. i was hoping this could be in a an array like structure of some kind. 4)update the db with the results.
I was thinking of using gsoap to write a simple c soap service that php can communicate with. Would this be the right way of doing this or would something like sockets in php be a better way of sending this volume of data as an array or struct to linux c socket if thats even possible.
I have a question about calling an asm function from C....It doesn't work unless I create an asm variable to hold the value of the function in....Why?Here's the code that doesn't work...
asmfile.s - version one Code: .section .data mydata: .ascii "this is the message! .equ mylen, . - mydata
I want to use backtrace() function to debug a crash issue. I tried this sample code to see how backtrace works. backtrace() function always returns 0 with the below code. Is there any kernel configuration that needs to be set for proper working of backtrace?
#include <execinfo.h> #include <stdio.h> #include <stdlib.h> /* Obtain a backtrace and print it to stdout. */ void print_trace (void)
Can you offer me the code about fmod() in C. I want to know how this function work, i am very interested in it because i have no idea to implement it, i want to know... how to write the function... not 'how to use the function' can anyone post the source codes of this function here?
i have an open source application that was developed in C++ (it uses objects and namespaces all over the place). I also have another application that was developed in C. Now i am trying to insert the code made in C into C++ application, but when i do that , i get this error on compilation of the source code:
Code: error: 'mpi_init_vars' was not declared in this scope the function mpi_init_vars() is not part of object oriented programming and it doesn't belong to any scope, it was compiled into an object file and i am linking it with all objects of C++ application.
How can invoke the C function from C++ object oriented code?
Code: #!/bin/sh #System commands and other configurable. IPT=/sbin/iptables IP6T=/sbin/ip6tables IPST=/usr/sbin/ipset MODP=/sbin/modprobe GET=/usr/bin/wget INT_NET=192.168.1.0/24 .....
I can find lots of tutorials in how to use if, then, else. However, how do I define a variable inside the function? SEE>> Code: for c in $ISO Also, am I using the 'test' command correctly( -/+ week as valid test)?
I am doing a web site program and what I need is to call a C program in the PHP cloud.Do u think it would be possible? The web site would get the user input from PHP UI and pass to the C program , the C program would process the function with the user input and output the a PHP page.
Code: return ((unsigned int)(unsigned long)base & TBASE_DEFERRABLE_FLAG); What is the above function returning.I am not clear with definition of what is being returned in the above code.
i want to compile function c in java and compile library is success.. when i call the library in java and error is :
Exception in thread "main" java.lang.UnsatisfiedLinkError: no libfunc.so in java.library.path at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1689) at java.lang.Runtime.loadLibrary0(Runtime.java:823) at java.lang.System.loadLibrary(System.java:1028)
