mirror of
https://github.com/jart/cosmopolitan.git
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f4f4caab0e
I wanted a tiny scriptable meltdown proof way to run userspace programs and visualize how program execution impacts memory. It helps to explain how things like Actually Portable Executable works. It can show you how the GCC generated code is going about manipulating matrices and more. I didn't feel fully comfortable with Qemu and Bochs because I'm not smart enough to understand them. I wanted something like gVisor but with much stronger levels of assurances. I wanted a single binary that'll run, on all major operating systems with an embedded GPL barrier ZIP filesystem that is tiny enough to transpile to JavaScript and run in browsers too. https://justine.storage.googleapis.com/emulator625.mp4
188 lines
7.3 KiB
C
188 lines
7.3 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ This program is free software; you can redistribute it and/or modify │
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│ it under the terms of the GNU General Public License as published by │
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│ the Free Software Foundation; version 2 of the License. │
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│ │
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│ This program is distributed in the hope that it will be useful, but │
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│ WITHOUT ANY WARRANTY; without even the implied warranty of │
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│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
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│ General Public License for more details. │
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│ │
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│ You should have received a copy of the GNU General Public License │
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│ along with this program; if not, write to the Free Software │
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
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│ 02110-1301 USA │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/bits/bits.h"
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#include "libc/calls/calls.h"
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#include "libc/calls/internal.h"
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#include "libc/calls/struct/sigaction-freebsd.h"
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#include "libc/calls/struct/sigaction-linux.h"
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#include "libc/calls/struct/sigaction-openbsd.h"
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#include "libc/calls/struct/sigaction-xnu.h"
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#include "libc/calls/struct/sigaction.h"
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#include "libc/calls/typedef/sigaction_f.h"
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#include "libc/calls/ucontext.h"
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#include "libc/dce.h"
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#include "libc/limits.h"
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#include "libc/macros.h"
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#include "libc/mem/mem.h"
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#include "libc/runtime/runtime.h"
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#include "libc/str/str.h"
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#include "libc/sysv/consts/sa.h"
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#include "libc/sysv/consts/sig.h"
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#include "libc/sysv/errfuns.h"
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union metasigaction {
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struct sigaction cosmo;
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struct sigaction$linux linux;
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struct sigaction$freebsd freebsd;
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struct sigaction$openbsd openbsd;
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struct sigaction$xnu_in xnu_in;
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struct sigaction$xnu_out xnu_out;
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};
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#define SWITCHEROO(S1, S2, A, B, C, D) \
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do { \
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autotype((S2).A) a = (typeof((S2).A))(S1).A; \
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autotype((S2).B) b = (typeof((S2).B))(S1).B; \
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autotype((S2).C) c = (typeof((S2).C))(S1).C; \
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typeof((S2).D) d; \
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memset(&d, 0, sizeof(d)); \
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memcpy(&d, &((S1).D), MIN(sizeof(d), sizeof((S1).D))); \
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(S2).A = a; \
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(S2).B = b; \
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(S2).C = c; \
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memset(&((S2).D), 0, sizeof((S2).D)); \
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memcpy(&((S2).D), &d, MIN(sizeof(d), sizeof((S2).D))); \
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} while (0);
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static void sigaction$cosmo2native(union metasigaction *sa) {
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if (!sa) return;
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switch (hostos) {
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case LINUX:
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SWITCHEROO(sa->cosmo, sa->linux, sa_handler, sa_flags, sa_restorer,
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sa_mask);
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break;
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case XNU:
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SWITCHEROO(sa->cosmo, sa->xnu_in, sa_handler, sa_flags, sa_restorer,
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sa_mask);
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break;
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case FREEBSD:
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SWITCHEROO(sa->cosmo, sa->freebsd, sa_handler, sa_flags, sa_flags,
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sa_mask);
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break;
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case OPENBSD:
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SWITCHEROO(sa->cosmo, sa->openbsd, sa_handler, sa_flags, sa_flags,
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sa_mask);
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break;
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default:
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abort();
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}
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}
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static void sigaction$native2cosmo(union metasigaction *sa) {
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if (!sa) return;
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switch (hostos) {
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case LINUX:
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SWITCHEROO(sa->linux, sa->cosmo, sa_handler, sa_flags, sa_restorer,
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sa_mask);
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break;
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case XNU:
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SWITCHEROO(sa->xnu_out, sa->cosmo, sa_handler, sa_flags, sa_flags,
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sa_mask);
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break;
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case FREEBSD:
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SWITCHEROO(sa->freebsd, sa->cosmo, sa_handler, sa_flags, sa_flags,
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sa_mask);
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break;
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case OPENBSD:
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SWITCHEROO(sa->openbsd, sa->cosmo, sa_handler, sa_flags, sa_flags,
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sa_mask);
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break;
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default:
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abort();
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}
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}
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/**
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* Installs handler for kernel interrupt, e.g.:
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*
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* void GotCtrlC(int sig, siginfo_t *si, ucontext_t *ctx);
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* struct sigaction sa = {.sa_sigaction = GotCtrlC,
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* .sa_flags = SA_RESETHAND|SA_RESTART|SA_SIGINFO};
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* CHECK_NE(-1, sigaction(SIGINT, &sa, NULL));
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*
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* @see xsigaction() for a much better api
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* @asyncsignalsafe
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*/
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int(sigaction)(int sig, const struct sigaction *act, struct sigaction *oldact) {
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static_assert(sizeof(struct sigaction) > sizeof(struct sigaction$linux) &&
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sizeof(struct sigaction) > sizeof(struct sigaction$xnu_in) &&
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sizeof(struct sigaction) > sizeof(struct sigaction$xnu_out) &&
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sizeof(struct sigaction) > sizeof(struct sigaction$freebsd) &&
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sizeof(struct sigaction) > sizeof(struct sigaction$openbsd));
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int rc, rva, oldrva;
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struct sigaction *ap, copy;
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if (!(0 < sig && sig < NSIG) || sig == SIGKILL || sig == SIGSTOP) {
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return einval();
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}
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if (!act) {
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rva = (int32_t)(intptr_t)SIG_DFL;
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} else if ((intptr_t)act->sa_handler < kSigactionMinRva) {
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rva = (int)(intptr_t)act->sa_handler;
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} else if ((intptr_t)act->sa_handler >= (intptr_t)&_base + kSigactionMinRva &&
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(intptr_t)act->sa_handler < (intptr_t)&_base + INT_MAX) {
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rva = (int)((uintptr_t)act->sa_handler - (uintptr_t)&_base);
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} else {
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return efault();
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}
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if (!IsWindows()) {
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if (act) {
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memcpy(©, act, sizeof(copy));
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ap = ©
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if (IsXnu()) {
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ap->sa_restorer = (void *)&xnutrampoline;
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ap->sa_handler = (void *)&xnutrampoline;
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} else {
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if (IsLinux()) {
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if (!(ap->sa_flags & SA_RESTORER)) {
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ap->sa_flags |= SA_RESTORER;
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ap->sa_restorer = &__restore_rt;
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}
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}
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if (rva >= 0) {
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ap->sa_sigaction = (sigaction_f)__sigenter;
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}
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}
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sigaction$cosmo2native((union metasigaction *)ap);
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} else {
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ap = NULL;
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}
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rc = sigaction$sysv(
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sig, ap, oldact,
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(!IsXnu() ? 8 /* or linux whines */
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: (int64_t)(intptr_t)oldact /* from go code */));
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if (rc != -1) sigaction$native2cosmo((union metasigaction *)oldact);
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} else {
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if (oldact) {
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memset(oldact, 0, sizeof(*oldact));
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}
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rc = 0;
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}
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if (rc != -1) {
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if (oldact) {
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oldrva = g_sighandrvas[sig];
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oldact->sa_sigaction = (sigaction_f)(
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oldrva < kSigactionMinRva ? oldrva : (intptr_t)&_base + oldrva);
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}
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if (act) {
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g_sighandrvas[sig] = rva;
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}
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}
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return rc;
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}
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