cosmopolitan/libc/calls/sigaction.c

189 lines
7.4 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ This program is free software; you can redistribute it and/or modify │
│ it under the terms of the GNU General Public License as published by │
│ the Free Software Foundation; version 2 of the License. │
│ │
│ This program is distributed in the hope that it will be useful, but │
│ WITHOUT ANY WARRANTY; without even the implied warranty of │
│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
│ General Public License for more details. │
│ │
│ You should have received a copy of the GNU General Public License │
│ along with this program; if not, write to the Free Software │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
│ 02110-1301 USA │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/bits/bits.h"
#include "libc/calls/calls.h"
#include "libc/calls/internal.h"
#include "libc/calls/struct/sigaction-freebsd.internal.h"
#include "libc/calls/struct/sigaction-linux.internal.h"
#include "libc/calls/struct/sigaction-openbsd.internal.h"
#include "libc/calls/struct/sigaction-xnu.internal.h"
#include "libc/calls/struct/sigaction.h"
#include "libc/calls/typedef/sigaction_f.h"
#include "libc/calls/ucontext.h"
#include "libc/dce.h"
#include "libc/limits.h"
#include "libc/macros.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/sa.h"
#include "libc/sysv/consts/sig.h"
#include "libc/sysv/errfuns.h"
union metasigaction {
struct sigaction cosmo;
struct sigaction$linux linux;
struct sigaction$freebsd freebsd;
struct sigaction$openbsd openbsd;
struct sigaction$xnu_in xnu_in;
struct sigaction$xnu_out xnu_out;
};
#define SWITCHEROO(S1, S2, A, B, C, D) \
do { \
autotype((S2).A) a = (typeof((S2).A))(S1).A; \
autotype((S2).B) b = (typeof((S2).B))(S1).B; \
autotype((S2).C) c = (typeof((S2).C))(S1).C; \
typeof((S2).D) d; \
memset(&d, 0, sizeof(d)); \
memcpy(&d, &((S1).D), MIN(sizeof(d), sizeof((S1).D))); \
(S2).A = a; \
(S2).B = b; \
(S2).C = c; \
memset(&((S2).D), 0, sizeof((S2).D)); \
memcpy(&((S2).D), &d, MIN(sizeof(d), sizeof((S2).D))); \
} while (0);
static void sigaction$cosmo2native(union metasigaction *sa) {
if (!sa) return;
switch (__hostos) {
case LINUX:
SWITCHEROO(sa->cosmo, sa->linux, sa_handler, sa_flags, sa_restorer,
sa_mask);
break;
case XNU:
SWITCHEROO(sa->cosmo, sa->xnu_in, sa_handler, sa_flags, sa_restorer,
sa_mask);
break;
case FREEBSD:
SWITCHEROO(sa->cosmo, sa->freebsd, sa_handler, sa_flags, sa_flags,
sa_mask);
break;
case OPENBSD:
SWITCHEROO(sa->cosmo, sa->openbsd, sa_handler, sa_flags, sa_flags,
sa_mask);
break;
default:
break;
}
}
static void sigaction$native2cosmo(union metasigaction *sa) {
if (!sa) return;
switch (__hostos) {
case LINUX:
SWITCHEROO(sa->linux, sa->cosmo, sa_handler, sa_flags, sa_restorer,
sa_mask);
break;
case XNU:
SWITCHEROO(sa->xnu_out, sa->cosmo, sa_handler, sa_flags, sa_flags,
sa_mask);
break;
case FREEBSD:
SWITCHEROO(sa->freebsd, sa->cosmo, sa_handler, sa_flags, sa_flags,
sa_mask);
break;
case OPENBSD:
SWITCHEROO(sa->openbsd, sa->cosmo, sa_handler, sa_flags, sa_flags,
sa_mask);
break;
default:
break;
}
}
/**
* Installs handler for kernel interrupt, e.g.:
*
* void GotCtrlC(int sig, siginfo_t *si, ucontext_t *ctx);
* struct sigaction sa = {.sa_sigaction = GotCtrlC,
* .sa_flags = SA_RESETHAND|SA_RESTART|SA_SIGINFO};
* CHECK_NE(-1, sigaction(SIGINT, &sa, NULL));
*
* @see xsigaction() for a much better api
* @asyncsignalsafe
*/
int(sigaction)(int sig, const struct sigaction *act, struct sigaction *oldact) {
static_assert(sizeof(struct sigaction) > sizeof(struct sigaction$linux) &&
sizeof(struct sigaction) > sizeof(struct sigaction$xnu_in) &&
sizeof(struct sigaction) > sizeof(struct sigaction$xnu_out) &&
sizeof(struct sigaction) > sizeof(struct sigaction$freebsd) &&
sizeof(struct sigaction) > sizeof(struct sigaction$openbsd));
int rc, rva, oldrva;
struct sigaction *ap, copy;
if (!(0 < sig && sig < NSIG) || sig == SIGKILL || sig == SIGSTOP) {
return einval();
}
if (!act) {
rva = (int32_t)(intptr_t)SIG_DFL;
} else if ((intptr_t)act->sa_handler < kSigactionMinRva) {
rva = (int)(intptr_t)act->sa_handler;
} else if ((intptr_t)act->sa_handler >= (intptr_t)&_base + kSigactionMinRva &&
(intptr_t)act->sa_handler < (intptr_t)&_base + INT_MAX) {
rva = (int)((uintptr_t)act->sa_handler - (uintptr_t)&_base);
} else {
return efault();
}
if (!IsWindows()) {
if (act) {
memcpy(&copy, act, sizeof(copy));
ap = &copy;
if (IsXnu()) {
ap->sa_restorer = (void *)&xnutrampoline;
ap->sa_handler = (void *)&xnutrampoline;
} else {
if (IsLinux()) {
if (!(ap->sa_flags & SA_RESTORER)) {
ap->sa_flags |= SA_RESTORER;
ap->sa_restorer = &__restore_rt;
}
}
if (rva >= kSigactionMinRva) {
ap->sa_sigaction = (sigaction_f)__sigenter;
}
}
sigaction$cosmo2native((union metasigaction *)ap);
} else {
ap = NULL;
}
rc = sigaction$sysv(
sig, ap, oldact,
(!IsXnu() ? 8 /* or linux whines */
: (int64_t)(intptr_t)oldact /* from go code */));
if (rc != -1) sigaction$native2cosmo((union metasigaction *)oldact);
} else {
if (oldact) {
memset(oldact, 0, sizeof(*oldact));
}
rc = 0;
}
if (rc != -1) {
if (oldact) {
oldrva = g_sighandrvas[sig];
oldact->sa_sigaction = (sigaction_f)(
oldrva < kSigactionMinRva ? oldrva : (intptr_t)&_base + oldrva);
}
if (act) {
g_sighandrvas[sig] = rva;
}
}
return rc;
}