To have more control over the device numbers and the device creation, you could do the following steps (instead of register_chrdev()): Call alloc_chrdev_region() to get a major number and a range of minor numbers to work with. Create a device class for your devices with class_create(). For each device, call cdev_init() and cdev_add() to add … Read more
Assume your socket is named s… you need to set socket.SO_REUSEADDR on the server’s socket before binding to an interface… this will allow you to immediately restart a TCP server… s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) s.bind((ADDR, PORT))
You could try cachegrind and it’s front-end kcachegrind.
You can replace each alphabetic character c with [cC], via import glob def insensitive_glob(pattern): def either(c): return ‘[%s%s]’ % (c.lower(), c.upper()) if c.isalpha() else c return glob.glob(”.join(map(either, pattern)))
When you call a function, a new “namespace” is allocated on the stack. That’s how functions can have local variables. As functions call functions, which in turn call functions, we keep allocating more and more space on the stack to maintain this deep hierarchy of namespaces. To curb programs using massive amounts of stack space, … Read more
Both Debian and Ubuntu ship with pam_umask. This allows you to configure umask in /etc/login.defs and have them apply system-wide, regardless of how a user logs in. To enable it, you may need to add a line to /etc/pam.d/common-session reading session optional pam_umask.so or it may already be enabled. Then edit /etc/login.defs and change the … Read more
From wikipedia Bash When Bash starts, it executes the commands in a variety of different scripts. When Bash is invoked as an interactive login shell, it first reads and executes commands from the file /etc/profile, if that file exists. After reading that file, it looks for ~/.bash_profile, ~/.bash_login, and ~/.profile, in that order, and reads … Read more
Here’s what’s going on: default_random_engine in libstdc++ (GCC’s standard library) is minstd_rand0, which is a simple linear congruential engine: typedef linear_congruential_engine<uint_fast32_t, 16807, 0, 2147483647> minstd_rand0; The way this engine generates random numbers is xi+1 = (16807xi + 0) mod 2147483647. Therefore, if the seeds are different by 1, then most of the time the first … Read more
CLOSE_WAIT means your program is still running, and hasn’t closed the socket (and the kernel is waiting for it to do so). Add -p to netstat to get the pid, and then kill it more forcefully (with SIGKILL if needed). That should get rid of your CLOSE_WAIT sockets. You can also use ps to find … Read more
The mktemp(1) man page explains it fairly well: Traditionally, many shell scripts take the name of the program with the pid as a suffix and use that as a temporary file name. This kind of naming scheme is predictable and the race condition it creates is easy for an attacker to win. A safer, though … Read more