1 /* The kernel call implemented in this file:
2 * m_type: SYS_RUNCTL
3 *
4 * The parameters for this kernel call are:
5 * m1_i1: RC_ENDPT process number to control
6 * m1_i2: RC_ACTION stop or resume the process
7 * m1_i3: RC_FLAGS request flags
8 */
9
10 #include "kernel/system.h"
11 #include <assert.h>
12
13 #if USE_RUNCTL
14
15 /*===========================================================================*
16 * do_runctl *
17 *===========================================================================*/
do_runctl(struct proc * caller,message * m_ptr)18 int do_runctl(struct proc * caller, message * m_ptr)
19 {
20 /* Control a process's RTS_PROC_STOP flag. Used for process management.
21 * If the process is queued sending a message or stopped for system call
22 * tracing, and the RC_DELAY request flag is given, set MF_SIG_DELAY instead
23 * of RTS_PROC_STOP, and send a SIGSNDELAY signal later when the process is done
24 * sending (ending the delay). Used by PM for safe signal delivery.
25 */
26 int proc_nr, action, flags;
27 register struct proc *rp;
28
29 /* Extract the message parameters and do sanity checking. */
30 if (!isokendpt(m_ptr->RC_ENDPT, &proc_nr)) return(EINVAL);
31 if (iskerneln(proc_nr)) return(EPERM);
32 rp = proc_addr(proc_nr);
33
34 action = m_ptr->RC_ACTION;
35 flags = m_ptr->RC_FLAGS;
36
37 /* Is the target sending or syscall-traced? Then set MF_SIG_DELAY instead.
38 * Do this only when the RC_DELAY flag is set in the request flags field.
39 * The process will not become runnable before PM has called SYS_ENDKSIG.
40 * Note that asynchronous messages are not covered: a process using SENDA
41 * should not also install signal handlers *and* expect POSIX compliance.
42 */
43
44 if (action == RC_STOP && (flags & RC_DELAY)) {
45 if (RTS_ISSET(rp, RTS_SENDING) || (rp->p_misc_flags & MF_SC_DEFER))
46 rp->p_misc_flags |= MF_SIG_DELAY;
47
48 if (rp->p_misc_flags & MF_SIG_DELAY)
49 return (EBUSY);
50 }
51
52 /* Either set or clear the stop flag. */
53 switch (action) {
54 case RC_STOP:
55 #if CONFIG_SMP
56 /* check if we must stop a process on a different CPU */
57 if (rp->p_cpu != cpuid) {
58 smp_schedule_stop_proc(rp);
59 break;
60 }
61 #endif
62 RTS_SET(rp, RTS_PROC_STOP);
63 break;
64 case RC_RESUME:
65 assert(RTS_ISSET(rp, RTS_PROC_STOP));
66 RTS_UNSET(rp, RTS_PROC_STOP);
67 break;
68 default:
69 return(EINVAL);
70 }
71
72 return(OK);
73 }
74
75 #endif /* USE_RUNCTL */
76
77