How can I detect parent process death in Linux OS? If in parent process called fork(), that create child process. In the parent process I can use system call wait() for waiting terminated child process, and getting its status. But, I can’t find info about how child process can detect parent process̵…
Tag: linux
How to get a pointer to a specific executable file’s section of a program from within itself? (Maybe with libelf)
I’m on a Linux environment and I need to make a program that retrieves some data that is placed in one of the sections of its executable file. So, how to get a pointer to a section of a program (by its name) from within itself? I know it’s possible to use elf_getdata() passing the index of the sec…
How to check if sed has changed a file
I am trying to find a clever way to figure out if the file passed to sed has been altered successfully or not. Basically, I want to know if the file has been changed or not without having to look at the file modification date. The reason why I need this is because I need to do some extra stuff
Context switches much slower in new linux kernels
We are looking to upgrade the OS on our servers from Ubuntu 10.04 LTS to Ubuntu 12.04 LTS. Unfortunately, it seems that the latency to run a thread that has become runnable has significantly increased from the 2.6 kernel to the 3.2 kernel. In fact the latency numbers we are getting are hard to believe. Let me…
Distinguish forwarding traffic and locally originated traffic in Linux network driver
Is there any information in the struct skbuff to distinguish between the forwarding traffic (bridge forwarding and ip forwarding) and locally originated traffic? We want to treat these two kinds of traffic differently in the network driver because the forwarding traffic do not require cache invalidation on th…
Track the time a command takes in UNIX/LINUX?
In UNIX/LINUX, is there an easy way to track the time a command takes? Answer Yes, use time <command>, such as Consult man time for more options. Link.
Nagios – Connection refused & Socket timeout
I need to monitor windows services(like CPU load, memory usage etc.), so I have installed Nagios monitoring tool. The installation is complete and ‘check_nt’ plugin is also installed. Upto this no error is there, but while executing scripts with agent NSClient++ ‘Connection refused by host&#…
Trying to launch an external editor from within a Go program
I am trying to figure out how to launch an external editor from within a Go program, wait for the user to close the editor, and then continue execution of the program. Based on this SO answer, I currently have this code: When I run the program, I get this: I have also tried using exec.Run() instead of exec.St…
How to use Callback function to get language in Tizen?
I want to write a native application in c to get the value of language in Tizen. The compiled c code must be run on the Tizen phone and I need to get the Value of language. The callback function i got from Tizen source is How to use this function to get the value of current language? Answer Since
How to access physical addresses from user space in Linux?
On a ARM based system running Linux, I have a device that’s memory mapped to a physical address. From a user space program where all addresses are virtual, how can I read content from this address? Answer You can map a device file to a user process memory using mmap(2) system call. Usually, device files…