Date: Tue, 31 Oct 2000 14:08:38 -0500 From: Raymond Law <rlaw@vt.edu> To: freebsd-questions@freebsd.org Subject: Re: Add a system call Message-ID: <4.3.0.20001031140540.00d90de0@mail.vt.edu> In-Reply-To: <39D10614.9ECD8635@yahoo.com>
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Can someone list the steps on how to add a system call in FreeBSD 4 please?
Thanks.
Ray,
At 03:24 PM 9/26/00 -0500, you wrote:
>Hi,
>
>I have been trying to insert a new system call (very simple),
>I have used the steps in the bottom without problems,
>but I don't understand the behavior of the program:
>
>::::::::::::::
>mysyscall.c
>::::::::::::::
>int mysyscall( int *n ) {
> printf("In the kernel!\n");
> *n = ( *n + 1000);
> return 0;
>}
>
>::::::::::::::
>myprog.c
>::::::::::::::
>int mysyscall (int * );
>
>int main (void){
> int x = 500;
> mysyscall(&x);
> printf("x= %i\n",x);
>}
>
>The kernel syscall apparently run but it doesn't modify the variable.
>
>$cc -o miprog miprog.c
>$ ./miprog
>x= 500
>
>In the kernel! <--- is showed in the console.
>
>If I compile with the function (syscall), it works apparently correctly.
>
>$cc -o miprog miprog.c mysyscall.c
>$ ./miprog
>In the kernel!
>x= 1500
>
>Thanks for your help.
>
>Yonny Cardenas B.
>
>--------------------------------------------------------------------------
>In Mon, 17 May 1999 Zhihui Zhang <zzhang@cs.binghamton.edu> wrote:
>
>I have used the following steps to add system calls to FreeBSD 3.1
>several
>times. Suppose you want to add a system call:
>int mysys(int a, int b, int c). You can do the following steps:
>
>(1) # cd /usr/src/sys/kern
>(2) # vi syscalls.master to add your system call into the file:
> 172 STD BSD { int mysys(int a, int b, int c); }
>(3) # sh makesyscalls.sh syscalls.master
> This creates three files: syscall.h, syscall-hide.h, and sysproto.h.
>(4) # vi mysys.c
> Edit your file to implement your mysys(). You can follow the file
> kern/vfs_syscalls.c.
>(6) # vi /sys/conf/files to add you file mysys.c into it.
>(7) Make a new kernel and install it (see FreeBSD handbook)
>The following steps update the libc library:
>(8) copy syscall.h, syscall-hide.h, and sysproto.h to /usr/include/sys
>(9) # cd /usr/src/lib/libc
>(10) # make obj
>(11) # make depend
>(12) # make all
>(13) # make insall
>Now you can reboot your machine and write a program that uses your
>mysys().
>--------------------------------------------------------------------------
>
>+-------------------------------------------------------------------------+
>| YONNY CARDENAS B. | Tels: +57 1 3451543, 3451554 |
>| | 3451565, 2176251 ext. 16 |
>| Opus Ingenieria | Fax : +57 1 3458343 |
>| Calle 61 # 5-44 Piso 3 | E-mail: y-carden@uniandes.edu.co |
>| Santafe de Bogota D.C.,Colombia | ycardena@yahoo.com |
>+-------------------------------------------------------------------------+
>
>
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