I’m trying to monitor syscalls for a binary using ptrace. The binary sleeps in pselect() and without ptrace, a SIGQUIT makes it return from pselect. The mask of blocked signals passed to pselect includes SIGQUIT. When executed with ptrace, it exits from sys_pselect6 but not all the way out of glibc̵…
Tag: signals
timer_create() not able to catch a signal in handler function
Here i am trying achieve a timer say 0-10secs and an interval of 2secs each,so that i need to generate an interrupt @ every 2secs(total 5 times) saying 2secs completed. which i have been cross checking in handler() function by using printf(). But i am not able to achieve the desired result.please put me touch…
Why is SIGFPE not triggered after adding a printf line?
I am playing with a simple program (source code below). And my computer configuration: Linux mymachine 3.13.0-49-generic #83-Ubuntu SMP Fri Apr 10 20:11:33 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux gcc version 4.8.4 (Ubuntu 4.8.4-2ubuntu1~14.04.3) I intend to trigger the SIGFPE in this program by calling the ex…
sigaction’s signal handler not called in child process
I’ve a program, which installs a signal handler for SIGSEGV. In signal handler ( I try to catch crash ) I restart my application. But when my application is resurrected it doesn’t handle SIGSEGV anymore. Here’s an example: what I get in output is: So I can see sighandler was set in right way…
SigCgt value is not getting updated in /proc//status file?
I have read about the signal handling in linux processes. I am using centOS 7.1 (kernel 3.10+). I am registering handler only for SIGTERM in my c++ program. As per my knowledge(not sure if my assumptions are correct). We can check all the signals a process is listening to in /proc/$pid/status file by using Si…
Which system calls are not interrupted by a signal?
AFAIK, most of the system calls on linux/unix are interrupted when a signal is received. According to the blog post below, there are some system calls that are not interrupted: In general function that return immediately (don’t wait for any I/O operation to complete or sleep) are not interruptible like …
Why can only async-signal-safe functions be called from signal handlers safely?
I am still a little confused as to why exactly it is unsafe to receive a signal and call a non async safe function from within that signal handler. Could someone explain the reasoning behind this and possibly try and give me some references that I can follow to read up more on this myself? In other words I am
Send signal to other process
since os/signal is only for handling of incoming signals I’m asking if there is a native way to send signals to other processes? Edit: The process I want to mange is nginx. My Go application should listen for some events and then send a SIGHUP to nginx to reload its configuration Answer If you have crea…
How to register a signal handler for a subprocess?
Adding a signal handler, e.g. with process.sh doesn’t work because CtrlC interrupts the child process (only SIGINT received is printed), but both SIGINT received and SIGINT child received should be printed and the child continue to run. Adding signal.SIG_IGN leaves the child untouched, but that not suff…
Safe global state for signal handling
I am toying around with Rust and various UNIX libraries. A use-case that I have right now is that I want to react to POSIX signals. To keep things reasonable I want to create an abstraction over the signal handling so that the rest of my program doesn’t have to worry about them as much. Let’s call…