kernel-module

How can I write human readable timestamp in linux kernel? I think do_gettimeofday returns epoch but I don't want to try to convert it to readable time. I just want a format like Hour:Min:Sec:Msec . Thanks Fred Later kernels have a function time_to_tm to break epoch time into human readable format. Here's an example: struct timeval t; struct tm broken; do_gettimeofday(&t); time_to_tm(t.tv_sec, 0, &broken); printk("%d:%d:%d:%ld\n", broken.tm_hour, broken.tm_min, broken.tm_sec, t.tv_usec); Again, this is only available in later kernels. The second parameter time_to_tm is an offset to the epoch

I am reviewing the kernel module example at this page The read_proc used in the program is as follows: int fortune_read( char *page, char **start, off_t off, int count, int *eof, void *data ) { int len; if (off > 0) { *eof = 1; return 0; } /* Wrap-around */ if (next_fortune >= cookie_index) next_fortune = 0; len = sprintf(page, "%s\n", &cookie_pot[next_fortune]); next_fortune += len; return len; } Can someone explain why off is checked to be greater than 0. Moreover can someone explain what is the importance of the off and count arguments. My understanding so far is that we have to write data

I'm writing an OSX kernel extension for an audio device driver (it's software, but emulates a hardware device). During development, it'd be convenient to completely uninstall existing old versions and then build and install the new version from scratch. However, this occasionally seems to not be possible without a system restart. The program itself is not running and the source files have been deleted from the /System/Library/Extensions/ dir. But kextstat reveals a single instance: $ kextstat | grep 'com.foo.driver.bar' 219 0 0xfff123 0x5000 0x5000 com.foo.driver.bar (0.0.1) <102 5 4 3> (..

I am trying to run following code, which was copied from here . I have made few changes to run it with older kernel versions. When I insert kernel module, nlmsg_multicast() fails and logs as nlmsg_multicast() error: -3 in /var/log/messages . While running user space program, socket() fails. What exactly I want to do is, kernel module creates a socket, regardless of any process in user space kernel module send some events to user space If any process in user space reply to an event, kernel module process on that reply Since, It may happen that no process in user space available to reply on

I have just made my first driver module, the hello world module following LDD3. However unfortunately encountered this error: insmod: error inserting './hello.ko': -1 Invalid module format. I am doing this on Ubuntu 11.04, and my environment: $ uname -r 2.6.38-8-generic I get the kernel source like this: sudo apt-cache search linux-source linux-source - Linux kernel source with Ubuntu patches linux-source-2.6.38 - Linux kernel source for version 2.6.38 with Ubuntu patches $sudo apt-get install linux-source-2.6.38 my /usr/src: $ls /usr/src/ linux-headers-2.6.38-8 linux-source-2.6.38 vboxguest-5

I am trying to get the battery level inside a Linux kernel module (the module is inserted via modprobe). I would ideally like to use a kernel API call to get the battery information. I have searched on the web for solutions, and I have also explored Linux kernel source and the source of program "acpi" by Michael Meskes for ideas. These are some of the techniques I think I can use: Read and parse /proc/acpi/battery/BAT0/state and /proc/acpi/battery/BAT0/info Read from /sys/class/power_supply/BAT0/charge_now and charge_full with no parsing involved. I could try using the calls from Linux kernel