Messages in this thread | | | Date | Tue, 12 Jan 2010 14:53:10 +0100 | Subject | add a new system call | From | mojtaba <> |
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[please cc kernelppc@gmail.com in your replies]
Dear all,
I need to add a new system call to the linux kernel.
These are the linux information: Linux ubuntu-desktop 2.6.32.3 #5 SMP Mon Jan 11 16:56:27 CET 2010 i686 GNU/Linux
I am working on kernel 2.6.32.
These are all the changes I did:
1- adding " .long sys_mycall" to the end of "arch/x86/kernel/syscall_table_32.S"
2- adding Code: #define __NR_mycall 242 __SYSCALL(__NR_mycall, sys_mycall) #undef __NR_syscalls #define __NR_syscalls 243 to the "include/asm-generic/unistd.h"
3- adding asmlinkage long sys_mycall(char * fname, void * params); to the end of "/include/linux/syscalls.h"
4-modifying the linux Makefile core-y += kernel/ mm/ fs/ ipc/ security/ crypto/ block/ mycall/
5- adding mycall folder to kernel source and mycall.c and the corresponding Makefile in it: Code: #include <linux/kernel.h> #include <linux/syscalls.h> SYSCALL_DEFINE2(mycall, char __user *, fname,void __user *,params) { printk("I am here !!"; return 10; } Now after building and installing the new kernel, I want to test the system call with this code:
Code: #include<stdio.h> #include <errno.h> #include<linux/unistd.h> #include <sys/syscall.h>
#define __NR_mycall 242
long mycall(char * fname, void * params ) { return syscall(__NR_mycall, fname, params); }
int main(void) { int tmp=10; int er=0; char * chp= (char *) &tmp; void * vp= (void *) &tmp; printf("%d\n", er=mycall(chp,vp)); if( er < 0 ) { printf( "Error: %d, %s\n", errno, strerror( errno ) ); } } Unfortunately, the code prints this: -1 Error: 3, No such process
And I have no idea what the problem is!
Is there any body who can help me?
Thank you and best regards, Mojtaba
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