minix/kernel/system/do_kill.c
Jorrit Herder 198c976f7e System processes can be signaled; signals are transformed in SYS_EVENT message
that passes signal map along. This mechanisms is also used for nonuser signals
like SIGKMESS, SIGKSTOP, SIGKSIG.

Revised comments of many system call handlers. Renamed setpriority to nice.
2005-07-19 12:21:36 +00:00

46 lines
1.6 KiB
C

/* The system call that is implemented in this file:
* m_type: SYS_KILL
*
* The parameters for this system call are:
* m2_i1: SIG_PROC # process to signal/ pending
* m2_i2: SIG_NUMBER # signal number to send to process
*/
#include "../system.h"
#include <signal.h>
#include <sys/sigcontext.h>
#if USE_KILL
/*===========================================================================*
* do_kill *
*===========================================================================*/
PUBLIC int do_kill(m_ptr)
message *m_ptr; /* pointer to request message */
{
/* Handle sys_kill(). Cause a signal to be sent to a process. The PM is the
* central server where all signals are processed and handler policies can
* be registered. Any request, except for PM requests, is added to the map
* of pending signals and the PM is informed about the new signal.
* Since system servers cannot use normal POSIX signal handlers (because they
* are usually blocked on a RECEIVE), they can request the PM to transform
* signals into messages. This is done by the PM with a call to sys_kill().
*/
proc_nr_t proc_nr = m_ptr->SIG_PROC;
int sig_nr = m_ptr->SIG_NUMBER;
if (! isokprocn(proc_nr) || sig_nr > _NSIG) return(EINVAL);
if (m_ptr->m_source == PM_PROC_NR) {
/* Directly send signal notification to a system process. */
if (! (priv(proc_addr(proc_nr))->s_flags & SYS_PROC)) return(EPERM);
send_sig(proc_nr, sig_nr);
} else {
/* Set pending signal to be processed by the PM. */
cause_sig(proc_nr, sig_nr);
}
return(OK);
}
#endif /* USE_KILL */