54 lines
2.1 KiB
C
54 lines
2.1 KiB
C
#include "ulib.h"
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/*
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* Only ever spawned by alarmtest.c. Installs NO sigAlrm handler at all --
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* the real-Unix default disposition for SIGALRM (signal.c's
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* sigDefaultIsIgnore explicitly does NOT list sigAlrm, so it falls through
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* to the same default-Terminate path every other "real" signal in this
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* kernel already has) is Terminate, not Ignore. userAlarm(1) schedules a
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* real SIGALRM one second from now against THIS process; the read below
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* blocks on a pipe no writer will ever attach to (the same "blocked
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* forever" setup eintrtarget.c/killvictim.c already use), so the only way
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* this process ever leaves that read is the alarm actually firing and
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* killing it -- exactly like eintrtarget.c, except the interrupting signal
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* here comes from schedule()'s own timer-tick expiry scan (sched.c), not
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* from another process's userSigSend. If threadSetAlarm/schedule's expiry
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* scan were ever broken, this process would simply never return from the
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* read below, hanging the whole boot gate to its 25s QEMU timeout instead
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* of merely failing a check -- the same fault-injection-visible shape
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* eintrtest.c's own file comment already establishes for early-wake.
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*/
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int main(void)
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{
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print("alarmdefault: start, pid=");
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printDec(userGetpid());
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print("\n");
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long victimHandle = userPipeCreate();
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if (victimHandle < 0) {
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print("alarmdefault: FAIL create victim pipe\n");
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return 1;
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}
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long victimFd = userPipeAttach(victimHandle, 0);
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if (victimFd < 0) {
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print("alarmdefault: FAIL attach victim pipe\n");
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return 1;
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}
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if (userAlarm(1) != 0) {
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print("alarmdefault: FAIL unexpected pre-existing alarm\n");
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return 1;
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}
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print("alarmdefault: blocking on read forever\n");
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char buffer[4];
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userRead((int)victimFd, buffer, sizeof(buffer));
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/* Only reached if userRead somehow returned on its own -- nothing ever
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writes to the victim pipe, so the alarm not firing (or firing but
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not actually terminating this process) is the only way to get here. */
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print("alarmdefault: FAIL read returned without being signaled\n");
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return 1;
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}
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