561 lines
11 KiB
C
561 lines
11 KiB
C
/* go-signal.c -- signal handling for Go.
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Copyright 2009 The Go Authors. All rights reserved.
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Use of this source code is governed by a BSD-style
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license that can be found in the LICENSE file. */
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#include <signal.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/time.h>
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#include "runtime.h"
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#include "go-assert.h"
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#include "go-panic.h"
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#include "signal_unix.h"
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#ifndef SA_RESTART
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#define SA_RESTART 0
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#endif
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#ifdef USING_SPLIT_STACK
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extern void __splitstack_getcontext(void *context[10]);
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extern void __splitstack_setcontext(void *context[10]);
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#endif
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#define N SigNotify
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#define K SigKill
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#define T SigThrow
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#define P SigPanic
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#define D SigDefault
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/* Signal actions. This collects the sigtab tables for several
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different targets from the master library. SIGKILL, SIGCONT, and
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SIGSTOP are not listed, as we don't want to set signal handlers for
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them. */
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SigTab runtime_sigtab[] = {
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#ifdef SIGHUP
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{ SIGHUP, N + K },
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#endif
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#ifdef SIGINT
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{ SIGINT, N + K },
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#endif
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#ifdef SIGQUIT
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{ SIGQUIT, N + T },
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#endif
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#ifdef SIGILL
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{ SIGILL, T },
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#endif
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#ifdef SIGTRAP
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{ SIGTRAP, T },
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#endif
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#ifdef SIGABRT
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{ SIGABRT, N + T },
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#endif
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#ifdef SIGBUS
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{ SIGBUS, P },
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#endif
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#ifdef SIGFPE
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{ SIGFPE, P },
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#endif
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#ifdef SIGUSR1
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{ SIGUSR1, N },
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#endif
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#ifdef SIGSEGV
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{ SIGSEGV, P },
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#endif
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#ifdef SIGUSR2
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{ SIGUSR2, N },
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#endif
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#ifdef SIGPIPE
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{ SIGPIPE, N },
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#endif
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#ifdef SIGALRM
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{ SIGALRM, N },
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#endif
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#ifdef SIGTERM
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{ SIGTERM, N + K },
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#endif
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#ifdef SIGSTKFLT
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{ SIGSTKFLT, T },
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#endif
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#ifdef SIGCHLD
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{ SIGCHLD, N },
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#endif
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#ifdef SIGTSTP
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{ SIGTSTP, N + D },
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#endif
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#ifdef SIGTTIN
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{ SIGTTIN, N + D },
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#endif
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#ifdef SIGTTOU
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{ SIGTTOU, N + D },
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#endif
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#ifdef SIGURG
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{ SIGURG, N },
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#endif
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#ifdef SIGXCPU
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{ SIGXCPU, N },
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#endif
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#ifdef SIGXFSZ
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{ SIGXFSZ, N },
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#endif
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#ifdef SIGVTALRM
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{ SIGVTALRM, N },
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#endif
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#ifdef SIGPROF
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{ SIGPROF, N },
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#endif
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#ifdef SIGWINCH
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{ SIGWINCH, N },
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#endif
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#ifdef SIGIO
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{ SIGIO, N },
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#endif
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#ifdef SIGPWR
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{ SIGPWR, N },
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#endif
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#ifdef SIGSYS
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{ SIGSYS, N },
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#endif
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#ifdef SIGEMT
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{ SIGEMT, T },
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#endif
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#ifdef SIGINFO
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{ SIGINFO, N },
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#endif
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#ifdef SIGTHR
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{ SIGTHR, N },
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#endif
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{ -1, 0 }
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};
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#undef N
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#undef K
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#undef T
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#undef P
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#undef D
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static int8 badsignal[] = "runtime: signal received on thread not created by Go.\n";
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static void
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runtime_badsignal(int32 sig)
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{
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// Avoid -D_FORTIFY_SOURCE problems.
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int rv __attribute__((unused));
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if (sig == SIGPROF) {
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return; // Ignore SIGPROFs intended for a non-Go thread.
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}
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rv = runtime_write(2, badsignal, sizeof badsignal - 1);
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runtime_exit(1);
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}
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/* Handle a signal, for cases where we don't panic. We can split the
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stack here. */
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void
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runtime_sighandler (int sig, Siginfo *info,
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void *context __attribute__ ((unused)), G *gp)
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{
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M *m;
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int i;
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m = runtime_m ();
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#ifdef SIGPROF
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if (sig == SIGPROF)
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{
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if (m != NULL && gp != m->g0 && gp != m->gsignal)
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runtime_sigprof ();
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return;
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}
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#endif
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if (m == NULL)
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{
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runtime_badsignal (sig);
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return;
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}
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for (i = 0; runtime_sigtab[i].sig != -1; ++i)
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{
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SigTab *t;
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bool notify, crash;
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t = &runtime_sigtab[i];
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if (t->sig != sig)
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continue;
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notify = false;
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#ifdef SA_SIGINFO
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notify = info != NULL && info->si_code == SI_USER;
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#endif
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if (notify || (t->flags & SigNotify) != 0)
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{
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if (__go_sigsend (sig))
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return;
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}
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if ((t->flags & SigKill) != 0)
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runtime_exit (2);
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if ((t->flags & SigThrow) == 0)
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return;
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runtime_startpanic ();
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{
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const char *name = NULL;
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#ifdef HAVE_STRSIGNAL
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name = strsignal (sig);
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#endif
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if (name == NULL)
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runtime_printf ("Signal %d\n", sig);
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else
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runtime_printf ("%s\n", name);
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}
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if (m->lockedg != NULL && m->ncgo > 0 && gp == m->g0)
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{
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runtime_printf("signal arrived during cgo execution\n");
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gp = m->lockedg;
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}
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runtime_printf ("\n");
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if (runtime_gotraceback (&crash))
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{
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G *g;
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g = runtime_g ();
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runtime_traceback (g);
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runtime_tracebackothers (g);
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/* The gc library calls runtime_dumpregs here, and provides
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a function that prints the registers saved in context in
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a readable form. */
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}
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if (crash)
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runtime_crash ();
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runtime_exit (2);
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}
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__builtin_unreachable ();
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}
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/* The start of handling a signal which panics. */
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static void
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sig_panic_leadin (int sig)
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{
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int i;
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sigset_t clear;
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if (runtime_m ()->mallocing)
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{
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runtime_printf ("caught signal while mallocing: %d\n", sig);
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runtime_throw ("caught signal while mallocing");
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}
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/* The signal handler blocked signals; unblock them. */
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i = sigfillset (&clear);
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__go_assert (i == 0);
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i = sigprocmask (SIG_UNBLOCK, &clear, NULL);
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__go_assert (i == 0);
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}
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#ifdef SA_SIGINFO
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/* Signal dispatch for signals which panic, on systems which support
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SA_SIGINFO. This is called on the thread stack, and as such it is
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permitted to split the stack. */
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static void
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sig_panic_info_handler (int sig, Siginfo *info, void *context)
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{
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G *g;
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g = runtime_g ();
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if (g == NULL || info->si_code == SI_USER)
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{
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runtime_sighandler (sig, info, context, g);
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return;
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}
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g->sig = sig;
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g->sigcode0 = info->si_code;
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g->sigcode1 = (uintptr_t) info->si_addr;
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/* It would be nice to set g->sigpc here as the gc library does, but
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I don't know how to get it portably. */
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sig_panic_leadin (sig);
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switch (sig)
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{
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#ifdef SIGBUS
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case SIGBUS:
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if (info->si_code == BUS_ADRERR && (uintptr_t) info->si_addr < 0x1000)
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runtime_panicstring ("invalid memory address or "
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"nil pointer dereference");
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runtime_printf ("unexpected fault address %p\n", info->si_addr);
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runtime_throw ("fault");
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#endif
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#ifdef SIGSEGV
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case SIGSEGV:
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if ((info->si_code == 0
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|| info->si_code == SEGV_MAPERR
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|| info->si_code == SEGV_ACCERR)
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&& (uintptr_t) info->si_addr < 0x1000)
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runtime_panicstring ("invalid memory address or "
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"nil pointer dereference");
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runtime_printf ("unexpected fault address %p\n", info->si_addr);
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runtime_throw ("fault");
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#endif
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#ifdef SIGFPE
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case SIGFPE:
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switch (info->si_code)
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{
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case FPE_INTDIV:
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runtime_panicstring ("integer divide by zero");
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case FPE_INTOVF:
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runtime_panicstring ("integer overflow");
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}
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runtime_panicstring ("floating point error");
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#endif
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}
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/* All signals with SigPanic should be in cases above, and this
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handler should only be invoked for those signals. */
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__builtin_unreachable ();
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}
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#else /* !defined (SA_SIGINFO) */
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static void
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sig_panic_handler (int sig)
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{
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G *g;
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g = runtime_g ();
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if (g == NULL)
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{
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runtime_sighandler (sig, NULL, NULL, g);
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return;
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}
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g->sig = sig;
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g->sigcode0 = 0;
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g->sigcode1 = 0;
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sig_panic_leadin (sig);
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switch (sig)
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{
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#ifdef SIGBUS
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case SIGBUS:
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runtime_panicstring ("invalid memory address or "
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"nil pointer dereference");
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#endif
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#ifdef SIGSEGV
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case SIGSEGV:
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runtime_panicstring ("invalid memory address or "
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"nil pointer dereference");
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#endif
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#ifdef SIGFPE
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case SIGFPE:
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runtime_panicstring ("integer divide by zero or floating point error");
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#endif
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}
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/* All signals with SigPanic should be in cases above, and this
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handler should only be invoked for those signals. */
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__builtin_unreachable ();
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}
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#endif /* !defined (SA_SIGINFO) */
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/* A signal handler used for signals which are not going to panic.
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This is called on the alternate signal stack so it may not split
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the stack. */
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static void
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sig_tramp_info (int, Siginfo *, void *) __attribute__ ((no_split_stack));
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static void
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sig_tramp_info (int sig, Siginfo *info, void *context)
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{
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G *gp;
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M *mp;
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/* We are now running on the stack registered via sigaltstack.
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(Actually there is a small span of time between runtime_siginit
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and sigaltstack when the program starts.) */
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gp = runtime_g ();
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mp = runtime_m ();
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if (gp != NULL)
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{
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#ifdef USING_SPLIT_STACK
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__splitstack_getcontext (&gp->stack_context[0]);
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#endif
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}
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if (gp != NULL && mp->gsignal != NULL)
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{
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/* We are running on the signal stack. Set the split stack
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context so that the stack guards are checked correctly. */
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#ifdef USING_SPLIT_STACK
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__splitstack_setcontext (&mp->gsignal->stack_context[0]);
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#endif
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}
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runtime_sighandler (sig, info, context, gp);
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/* We are going to return back to the signal trampoline and then to
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whatever we were doing before we got the signal. Restore the
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split stack context so that stack guards are checked
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correctly. */
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if (gp != NULL)
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{
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#ifdef USING_SPLIT_STACK
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__splitstack_setcontext (&gp->stack_context[0]);
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#endif
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}
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}
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#ifndef SA_SIGINFO
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static void sig_tramp (int sig) __attribute__ ((no_split_stack));
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static void
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sig_tramp (int sig)
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{
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sig_tramp_info (sig, NULL, NULL);
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}
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#endif
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void
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runtime_setsig (int32 i, GoSighandler *fn, bool restart)
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{
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struct sigaction sa;
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int r;
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SigTab *t;
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memset (&sa, 0, sizeof sa);
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r = sigfillset (&sa.sa_mask);
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__go_assert (r == 0);
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t = &runtime_sigtab[i];
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if ((t->flags & SigPanic) == 0)
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{
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#ifdef SA_SIGINFO
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sa.sa_flags = SA_ONSTACK | SA_SIGINFO;
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if (fn == runtime_sighandler)
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fn = (void *) sig_tramp_info;
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sa.sa_sigaction = (void *) fn;
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#else
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sa.sa_flags = SA_ONSTACK;
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if (fn == runtime_sighandler)
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fn = (void *) sig_tramp;
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sa.sa_handler = (void *) fn;
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#endif
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}
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else
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{
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#ifdef SA_SIGINFO
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sa.sa_flags = SA_SIGINFO;
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if (fn == runtime_sighandler)
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fn = (void *) sig_panic_info_handler;
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sa.sa_sigaction = (void *) fn;
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#else
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sa.sa_flags = 0;
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if (fn == runtime_sighandler)
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fn = (void *) sig_panic_handler;
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sa.sa_handler = (void *) fn;
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#endif
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}
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if (restart)
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sa.sa_flags |= SA_RESTART;
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if (sigaction (t->sig, &sa, NULL) != 0)
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__go_assert (0);
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}
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GoSighandler*
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runtime_getsig (int32 i)
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{
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struct sigaction sa;
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int r;
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SigTab *t;
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memset (&sa, 0, sizeof sa);
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r = sigemptyset (&sa.sa_mask);
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__go_assert (r == 0);
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t = &runtime_sigtab[i];
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if (sigaction (t->sig, NULL, &sa) != 0)
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runtime_throw ("sigaction read failure");
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if ((void *) sa.sa_handler == sig_tramp_info)
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return runtime_sighandler;
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#ifdef SA_SIGINFO
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if ((void *) sa.sa_handler == sig_panic_info_handler)
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return runtime_sighandler;
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#else
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if ((void *) sa.sa_handler == sig_tramp
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|| (void *) sa.sa_handler == sig_panic_handler)
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return runtime_sighandler;
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#endif
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return (void *) sa.sa_handler;
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}
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/* Used by the os package to raise SIGPIPE. */
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void os_sigpipe (void) __asm__ (GOSYM_PREFIX "os.sigpipe");
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void
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os_sigpipe (void)
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{
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struct sigaction sa;
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int i;
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memset (&sa, 0, sizeof sa);
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sa.sa_handler = SIG_DFL;
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i = sigemptyset (&sa.sa_mask);
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__go_assert (i == 0);
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if (sigaction (SIGPIPE, &sa, NULL) != 0)
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abort ();
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raise (SIGPIPE);
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}
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void
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runtime_setprof(bool on)
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{
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USED(on);
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}
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