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Old 04-13-2010, 10:10 AM   #1
flea89
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Problem with kernel call


Hello everyone. I am trying to make a new kernel call in minix, which will get an integer as input and return the mux of this integer * 4260.

I have made the nessecary additions (according to other existing kernel calls) in:
Makefile (cd /usr/src/kernel/system)
com.h (cd /usr/src/include/minix)
system.h and system.c (cd /usr/src/kernel)

Now, I have also created two .c files
The following one, do_mux.c is in /usr/src/kernel/system:
Code:
#if USE_MUX

PUBLIC int do_mux(m_ptr)
message *m_ptr;
{
	int num;
	
	num = m_ptr->m1_i1; /* num takes the value of m1_i1 of passed message structure */
						/* in which m_ptr points to */
	return num * 4260; /* return the mux of given number x AM number */
}

#endif /* USE_MUX */
and this one, 3.c is in /usr/src/kernel
Code:
#include <lib.h>
#include <minix/com.h>
#include <stdio.h>
#include <stdlib.h>
#include <minix/syslib.h>

int my_mux(int num)
{
	message m; /* creates the message structure which will pass to kernel call do_mux */
	
	m.m1_i1 = num; /* stores the value of num into an integer member of message structure m */
					/* in order to pass its value into the kernel call */
	return (_taskcall(SYSTASK, SYS_MUX, &m)); /* invokes do_mux kernel call */
}

int main(int argc, char *argv[2])
{
	int number = atoi(argv[1]); /* converts the second argument passed into its integer representation */
	
	printf("\n%d*4260 = %d\n", number, my_mux(number)); /* prints the mux of the given number x 4260 calculated by the kernel call do_mux */
	
	return 0; /* terminates */
}
The thing was, after saying 'make hdboot' (for the changes to work), and rebooting minix, to run
3.c and get for example, if I run it with 1 as input,
1x4260=4260
Instead, with whatever input i run it, it prints =-104.
I know that -104 means CALL DENIED, but I really dont know how to fix this...
Any ideas? sorry for the extra large post
 
Old 04-13-2010, 11:22 AM   #2
unSpawn
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Please post your thread once and in only one forum. Posting a single thread in the most relevant forum will make it easier for members to help you and will keep the discussion in one place. This thread should be closed because it is a duplicate of http://www.linuxquestions.org/questi...l-call-801763/.
 
Old 04-13-2010, 01:12 PM   #3
Tinkster
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Closing the original in favour of the more sensibly placed dupe.
 
  


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