71 lines
2.1 KiB
C
71 lines
2.1 KiB
C
/* The kernel call implemented in this file:
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* m_type: SYS_RUNCTL
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*
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* The parameters for this kernel call are:
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* m1_i1: RC_ENDPT process number to control
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* m1_i2: RC_ACTION stop or resume the process
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* m1_i3: RC_FLAGS request flags
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*/
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#include "../system.h"
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#if USE_RUNCTL
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/*===========================================================================*
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* do_runctl *
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*===========================================================================*/
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PUBLIC int do_runctl(message *m_ptr)
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{
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/* Control a process's RTS_PROC_STOP flag. Used for process management.
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* If the process is queued sending a message or stopped for system call
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* tracing, and the RC_DELAY request flag is given, set MF_SIG_DELAY instead
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* of RTS_PROC_STOP, and send a SIGNDELAY signal later when the process is done
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* sending (ending the delay). Used by PM for safe signal delivery.
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*/
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int proc_nr, action, flags, delayed;
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register struct proc *rp;
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/* Extract the message parameters and do sanity checking. */
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if (!isokendpt(m_ptr->RC_ENDPT, &proc_nr)) return(EINVAL);
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if (iskerneln(proc_nr)) return(EPERM);
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rp = proc_addr(proc_nr);
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action = m_ptr->RC_ACTION;
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flags = m_ptr->RC_FLAGS;
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/* Is the target sending or syscall-traced? Then set MF_SIG_DELAY instead.
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* Do this only when the RC_DELAY flag is set in the request flags field.
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* The process will not become runnable before PM has called SYS_ENDKSIG.
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* Note that asynchronous messages are not covered: a process using SENDA
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* should not also install signal handlers *and* expect POSIX compliance.
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*/
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if (action == RC_STOP && (flags & RC_DELAY)) {
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RTS_LOCK_SET(rp, RTS_SYS_LOCK);
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if (RTS_ISSET(rp, RTS_SENDING) || (rp->p_misc_flags & MF_SC_DEFER))
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rp->p_misc_flags |= MF_SIG_DELAY;
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delayed = (rp->p_misc_flags & MF_SIG_DELAY);
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RTS_LOCK_UNSET(rp, RTS_SYS_LOCK);
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if (delayed) return(EBUSY);
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}
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/* Either set or clear the stop flag. */
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switch (action) {
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case RC_STOP:
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RTS_LOCK_SET(rp, RTS_PROC_STOP);
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break;
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case RC_RESUME:
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RTS_LOCK_UNSET(rp, RTS_PROC_STOP);
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break;
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default:
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return(EINVAL);
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}
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return(OK);
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}
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#endif /* USE_RUNCTL */
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