Executing a Minix kernel call

Question

I have followed this tutorial - https://wiki.minix3.org/doku.php?id=developersguide:newkernelcall to add a new kernel call, but how do I invoke it from a userspace program? I understand I should be able to use the syscall() function, but what arguments do I provide to it and what files do I need to include? Any help would be appreciated. Thanks

Answer 1

after followed https://wiki.minix3.org/doku.php?id=developersguide:newkernelcall to add a Kernel Call (SYS_SAMPLE 58) in Minix 3.4.0 rc6, I am using below code that basically coming from Example 1 of https://wiki.minix3.org/doku.php?id=developersguide:driverprogramming to test this Kernel Call 58

#include <stdio.h>
#include <stdlib.h>
#include <minix/syslib.h>
 
int main(int argc, char **argv)
{
    sef_startup();
 
    endpoint_t ept;
    unsigned flags;

    int r = sys_sample(flags, ept);
    
    printf("Hello, World %d!\n", r);
    return EXIT_SUCCESS;
}

process:

minix code is in /home/user/minix/src/minix/

1. su // change to root
2. cp /home/user/minix/src/minix/minix/include/minix/com.h /usr/include/minix/com.h // use modified com.h while making new kernel etc.
3. cp /home/user/minix/src/minix/minix/include/minix/syslib.h /usr/include/minix/syslib.h

// make and use new kernel

4. cd /boot/minix_default/
5. mv kernel kernel.20240129 // back up original kernel
6. cd /home/user/minix/src/minix/minix/kernel
7. make
8. cp kernel /boot/minix_default/kernel

// make and use new libsys.a

9. cd /usr/lib
10. mv libsys.a libsys.a.20240129
11. mv libsys.so.0.0 libsys.so.0.0.20240129
12. cd /home/user/minix/src/minix/minix/lib/libsys
13. make
14. cp libsys.a /usr/lib/libsys.a
15. cp libsys.so.0.0 /usr/lib/libsys.so.0.0

// make and use new minix-service

16. cd /sbin
17. mv minix-service minix-service.20240129
18. cd /home/user/minix/src/minix/minix/commands/minix-service
19. make
20. make install

//make and run test driver hello1

21. reboot, then start Minix with Option "2"
22. cd /home/user/minix/src/minix/minix/drivers/examples/hello1
23. make clean
24. make
25. make install
26. minix-service up /service/hello1
27. minix-service down hello1

runnig result in Minix although denied, seems called Kernel Call 58