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ruby--ruby/signal.c
normal 475b4aa40b simplify altstack and enable reuse with thread cache 
Instead of allocating and registering the altstack in different
places, do it together to reduce code and improve readability.
When thread cache is enabled, storing altstack in rb_thread_t
is wasteful and we may reuse altstack in the same pthread.

This also lets us clearly allow use of xmalloc to allow GC to
recover from ENOMEM.

[ruby-core:85621] [Feature #14487]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63213 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
2018-04-20 21:38:27 +00:00

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34 KiB
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/**********************************************************************
signal.c -
$Author$
created at: Tue Dec 20 10:13:44 JST 1994
Copyright (C) 1993-2007 Yukihiro Matsumoto
Copyright (C) 2000 Network Applied Communication Laboratory, Inc.
Copyright (C) 2000 Information-technology Promotion Agency, Japan
**********************************************************************/
#include "internal.h"
#include "vm_core.h"
#include <signal.h>
#include <stdio.h>
#include <errno.h>
#include "ruby_atomic.h"
#include "eval_intern.h"
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#ifdef HAVE_SYS_UIO_H
#include <sys/uio.h>
#endif
#ifdef HAVE_UCONTEXT_H
#include <ucontext.h>
#endif
#ifdef HAVE_VALGRIND_MEMCHECK_H
# include <valgrind/memcheck.h>
# ifndef VALGRIND_MAKE_MEM_DEFINED
# define VALGRIND_MAKE_MEM_DEFINED(p, n) VALGRIND_MAKE_READABLE((p), (n))
# endif
# ifndef VALGRIND_MAKE_MEM_UNDEFINED
# define VALGRIND_MAKE_MEM_UNDEFINED(p, n) VALGRIND_MAKE_WRITABLE((p), (n))
# endif
#else
# define VALGRIND_MAKE_MEM_DEFINED(p, n) 0
# define VALGRIND_MAKE_MEM_UNDEFINED(p, n) 0
#endif
#ifdef NEED_RUBY_ATOMIC_OPS
rb_atomic_t
ruby_atomic_exchange(rb_atomic_t *ptr, rb_atomic_t val)
{
rb_atomic_t old = *ptr;
*ptr = val;
return old;
}
rb_atomic_t
ruby_atomic_compare_and_swap(rb_atomic_t *ptr, rb_atomic_t cmp,
rb_atomic_t newval)
{
rb_atomic_t old = *ptr;
if (old == cmp) {
*ptr = newval;
}
return old;
}
#endif
#ifndef NSIG
# define NSIG (_SIGMAX + 1) /* For QNX */
#endif
static const struct signals {
const char *signm;
int signo;
} siglist [] = {
{"EXIT", 0},
#ifdef SIGHUP
{"HUP", SIGHUP},
#endif
{"INT", SIGINT},
#ifdef SIGQUIT
{"QUIT", SIGQUIT},
#endif
#ifdef SIGILL
{"ILL", SIGILL},
#endif
#ifdef SIGTRAP
{"TRAP", SIGTRAP},
#endif
#ifdef SIGABRT
{"ABRT", SIGABRT},
#endif
#ifdef SIGIOT
{"IOT", SIGIOT},
#endif
#ifdef SIGEMT
{"EMT", SIGEMT},
#endif
#ifdef SIGFPE
{"FPE", SIGFPE},
#endif
#ifdef SIGKILL
{"KILL", SIGKILL},
#endif
#ifdef SIGBUS
{"BUS", SIGBUS},
#endif
#ifdef SIGSEGV
{"SEGV", SIGSEGV},
#endif
#ifdef SIGSYS
{"SYS", SIGSYS},
#endif
#ifdef SIGPIPE
{"PIPE", SIGPIPE},
#endif
#ifdef SIGALRM
{"ALRM", SIGALRM},
#endif
#ifdef SIGTERM
{"TERM", SIGTERM},
#endif
#ifdef SIGURG
{"URG", SIGURG},
#endif
#ifdef SIGSTOP
{"STOP", SIGSTOP},
#endif
#ifdef SIGTSTP
{"TSTP", SIGTSTP},
#endif
#ifdef SIGCONT
{"CONT", SIGCONT},
#endif
#ifdef SIGCHLD
{"CHLD", SIGCHLD},
#endif
#ifdef SIGCLD
{"CLD", SIGCLD},
#else
# ifdef SIGCHLD
{"CLD", SIGCHLD},
# endif
#endif
#ifdef SIGTTIN
{"TTIN", SIGTTIN},
#endif
#ifdef SIGTTOU
{"TTOU", SIGTTOU},
#endif
#ifdef SIGIO
{"IO", SIGIO},
#endif
#ifdef SIGXCPU
{"XCPU", SIGXCPU},
#endif
#ifdef SIGXFSZ
{"XFSZ", SIGXFSZ},
#endif
#ifdef SIGVTALRM
{"VTALRM", SIGVTALRM},
#endif
#ifdef SIGPROF
{"PROF", SIGPROF},
#endif
#ifdef SIGWINCH
{"WINCH", SIGWINCH},
#endif
#ifdef SIGUSR1
{"USR1", SIGUSR1},
#endif
#ifdef SIGUSR2
{"USR2", SIGUSR2},
#endif
#ifdef SIGLOST
{"LOST", SIGLOST},
#endif
#ifdef SIGMSG
{"MSG", SIGMSG},
#endif
#ifdef SIGPWR
{"PWR", SIGPWR},
#endif
#ifdef SIGPOLL
{"POLL", SIGPOLL},
#endif
#ifdef SIGDANGER
{"DANGER", SIGDANGER},
#endif
#ifdef SIGMIGRATE
{"MIGRATE", SIGMIGRATE},
#endif
#ifdef SIGPRE
{"PRE", SIGPRE},
#endif
#ifdef SIGGRANT
{"GRANT", SIGGRANT},
#endif
#ifdef SIGRETRACT
{"RETRACT", SIGRETRACT},
#endif
#ifdef SIGSOUND
{"SOUND", SIGSOUND},
#endif
#ifdef SIGINFO
{"INFO", SIGINFO},
#endif
{NULL, 0}
};
static const char signame_prefix[3] = "SIG";
static const int signame_prefix_len = (int)sizeof(signame_prefix);
static int
signm2signo(VALUE *sig_ptr, int negative, int exit, int *prefix_ptr)
{
const struct signals *sigs;
VALUE vsig = *sig_ptr;
const char *nm;
long len;
int prefix = 0;
if (RB_SYMBOL_P(vsig)) {
*sig_ptr = vsig = rb_sym2str(vsig);
}
else if (!RB_TYPE_P(vsig, T_STRING)) {
VALUE str = rb_check_string_type(vsig);
if (NIL_P(str)) {
rb_raise(rb_eArgError, "bad signal type %s",
rb_obj_classname(vsig));
}
*sig_ptr = vsig = str;
}
rb_must_asciicompat(vsig);
RSTRING_GETMEM(vsig, nm, len);
if (memchr(nm, '\0', len)) {
rb_raise(rb_eArgError, "signal name with null byte");
}
if (len > 0 && nm[0] == '-') {
if (!negative)
rb_raise(rb_eArgError, "negative signal name: % "PRIsVALUE, vsig);
prefix = 1;
}
else {
negative = 0;
}
if (len >= prefix + signame_prefix_len) {
if (memcmp(nm + prefix, signame_prefix, sizeof(signame_prefix)) == 0)
prefix += signame_prefix_len;
}
if (len <= (long)prefix) {
unsupported:
if (prefix == signame_prefix_len) {
prefix = 0;
}
else if (prefix > signame_prefix_len) {
prefix -= signame_prefix_len;
len -= prefix;
vsig = rb_str_subseq(vsig, prefix, len);
prefix = 0;
}
else {
len -= prefix;
vsig = rb_str_subseq(vsig, prefix, len);
prefix = signame_prefix_len;
}
rb_raise(rb_eArgError, "unsupported signal `%.*s%"PRIsVALUE"'",
prefix, signame_prefix, vsig);
}
if (prefix_ptr) *prefix_ptr = prefix;
for (sigs = siglist + !exit; sigs->signm; sigs++) {
if (memcmp(sigs->signm, nm + prefix, len - prefix) == 0 &&
sigs->signm[len - prefix] == '\0') {
return negative ? -sigs->signo : sigs->signo;
}
}
goto unsupported;
}
static const char*
signo2signm(int no)
{
const struct signals *sigs;
for (sigs = siglist; sigs->signm; sigs++)
if (sigs->signo == no)
return sigs->signm;
return 0;
}
/*
* call-seq:
* Signal.signame(signo) -> string or nil
*
* Convert signal number to signal name.
* Returns +nil+ if the signo is an invalid signal number.
*
* Signal.trap("INT") { |signo| puts Signal.signame(signo) }
* Process.kill("INT", 0)
*
* <em>produces:</em>
*
* INT
*/
static VALUE
sig_signame(VALUE recv, VALUE signo)
{
const char *signame = signo2signm(NUM2INT(signo));
if (!signame) return Qnil;
return rb_str_new_cstr(signame);
}
const char *
ruby_signal_name(int no)
{
return signo2signm(no);
}
static VALUE
rb_signo2signm(int signo)
{
const char *const signm = signo2signm(signo);
if (signm) {
return rb_sprintf("SIG%s", signm);
}
else {
return rb_sprintf("SIG%u", signo);
}
}
/*
* call-seq:
* SignalException.new(sig_name) -> signal_exception
* SignalException.new(sig_number [, name]) -> signal_exception
*
* Construct a new SignalException object. +sig_name+ should be a known
* signal name.
*/
static VALUE
esignal_init(int argc, VALUE *argv, VALUE self)
{
int argnum = 1;
VALUE sig = Qnil;
int signo;
if (argc > 0) {
sig = rb_check_to_integer(argv[0], "to_int");
if (!NIL_P(sig)) argnum = 2;
else sig = argv[0];
}
rb_check_arity(argc, 1, argnum);
if (argnum == 2) {
signo = NUM2INT(sig);
if (signo < 0 || signo > NSIG) {
rb_raise(rb_eArgError, "invalid signal number (%d)", signo);
}
if (argc > 1) {
sig = argv[1];
}
else {
sig = rb_signo2signm(signo);
}
}
else {
int prefix;
signo = signm2signo(&sig, FALSE, FALSE, &prefix);
if (prefix != signame_prefix_len) {
sig = rb_str_append(rb_str_new_cstr("SIG"), sig);
}
}
rb_call_super(1, &sig);
rb_ivar_set(self, id_signo, INT2NUM(signo));
return self;
}
/*
* call-seq:
* signal_exception.signo -> num
*
* Returns a signal number.
*/
static VALUE
esignal_signo(VALUE self)
{
return rb_ivar_get(self, id_signo);
}
/* :nodoc: */
static VALUE
interrupt_init(int argc, VALUE *argv, VALUE self)
{
VALUE args[2];
args[0] = INT2FIX(SIGINT);
rb_scan_args(argc, argv, "01", &args[1]);
return rb_call_super(2, args);
}
void
ruby_default_signal(int sig)
{
signal(sig, SIG_DFL);
raise(sig);
}
static RETSIGTYPE sighandler(int sig);
static int signal_ignored(int sig);
static void signal_enque(int sig);
/*
* call-seq:
* Process.kill(signal, pid, ...) -> integer
*
* Sends the given signal to the specified process id(s) if _pid_ is positive.
* If _pid_ is zero _signal_ is sent to all processes whose group ID is equal
* to the group ID of the process. _signal_ may be an integer signal number or
* a POSIX signal name (either with or without a +SIG+ prefix). If _signal_ is
* negative (or starts with a minus sign), kills process groups instead of
* processes. Not all signals are available on all platforms.
* The keys and values of +Signal.list+ are known signal names and numbers,
* respectively.
*
* pid = fork do
* Signal.trap("HUP") { puts "Ouch!"; exit }
* # ... do some work ...
* end
* # ...
* Process.kill("HUP", pid)
* Process.wait
*
* <em>produces:</em>
*
* Ouch!
*
* If _signal_ is an integer but wrong for signal,
* <code>Errno::EINVAL</code> or +RangeError+ will be raised.
* Otherwise unless _signal_ is a +String+ or a +Symbol+, and a known
* signal name, +ArgumentError+ will be raised.
*
* Also, <code>Errno::ESRCH</code> or +RangeError+ for invalid _pid_,
* <code>Errno::EPERM</code> when failed because of no privilege,
* will be raised. In these cases, signals may have been sent to
* preceding processes.
*/
VALUE
rb_f_kill(int argc, const VALUE *argv)
{
#ifndef HAVE_KILLPG
#define killpg(pg, sig) kill(-(pg), (sig))
#endif
int sig;
int i;
VALUE str;
rb_check_arity(argc, 2, UNLIMITED_ARGUMENTS);
if (FIXNUM_P(argv[0])) {
sig = FIX2INT(argv[0]);
}
else {
str = argv[0];
sig = signm2signo(&str, TRUE, FALSE, NULL);
}
if (argc <= 1) return INT2FIX(0);
if (sig < 0) {
sig = -sig;
for (i=1; i<argc; i++) {
if (killpg(NUM2PIDT(argv[i]), sig) < 0)
rb_sys_fail(0);
}
}
else {
const rb_pid_t self = (GET_THREAD() == GET_VM()->main_thread) ? getpid() : -1;
int wakeup = 0;
for (i=1; i<argc; i++) {
rb_pid_t pid = NUM2PIDT(argv[i]);
if ((sig != 0) && (self != -1) && (pid == self)) {
int t;
/*
* When target pid is self, many caller assume signal will be
* delivered immediately and synchronously.
*/
switch (sig) {
case SIGSEGV:
#ifdef SIGBUS
case SIGBUS:
#endif
#ifdef SIGKILL
case SIGKILL:
#endif
#ifdef SIGILL
case SIGILL:
#endif
#ifdef SIGFPE
case SIGFPE:
#endif
#ifdef SIGSTOP
case SIGSTOP:
#endif
kill(pid, sig);
break;
default:
t = signal_ignored(sig);
if (t) {
if (t < 0 && kill(pid, sig))
rb_sys_fail(0);
break;
}
signal_enque(sig);
wakeup = 1;
}
}
else if (kill(pid, sig) < 0) {
rb_sys_fail(0);
}
}
if (wakeup) {
rb_threadptr_check_signal(GET_VM()->main_thread);
}
}
rb_thread_execute_interrupts(rb_thread_current());
return INT2FIX(i-1);
}
static struct {
rb_atomic_t cnt[RUBY_NSIG];
rb_atomic_t size;
} signal_buff;
#ifdef __dietlibc__
#define sighandler_t sh_t
#else
#define sighandler_t ruby_sighandler_t
#endif
typedef RETSIGTYPE (*sighandler_t)(int);
#ifdef USE_SIGALTSTACK
typedef void ruby_sigaction_t(int, siginfo_t*, void*);
#define SIGINFO_ARG , siginfo_t *info, void *ctx
#define SIGINFO_CTX ctx
#else
typedef RETSIGTYPE ruby_sigaction_t(int);
#define SIGINFO_ARG
#define SIGINFO_CTX 0
#endif
#ifdef USE_SIGALTSTACK
static int
rb_sigaltstack_size(void)
{
/* XXX: BSD_vfprintf() uses >1500KiB stack and x86-64 need >5KiB stack. */
int size = 16*1024;
#ifdef MINSIGSTKSZ
if (size < MINSIGSTKSZ)
size = MINSIGSTKSZ;
#endif
#if defined(HAVE_SYSCONF) && defined(_SC_PAGE_SIZE)
{
int pagesize;
pagesize = (int)sysconf(_SC_PAGE_SIZE);
if (size < pagesize)
size = pagesize;
}
#endif
return size;
}
/* alternate stack for SIGSEGV */
void *
rb_register_sigaltstack(void)
{
stack_t newSS, oldSS;
newSS.ss_size = rb_sigaltstack_size();
newSS.ss_sp = xmalloc(newSS.ss_size);
newSS.ss_flags = 0;
sigaltstack(&newSS, &oldSS); /* ignore error. */
return newSS.ss_sp;
}
#endif /* USE_SIGALTSTACK */
#ifdef POSIX_SIGNAL
static sighandler_t
ruby_signal(int signum, sighandler_t handler)
{
struct sigaction sigact, old;
#if 0
rb_trap_accept_nativethreads[signum] = 0;
#endif
sigemptyset(&sigact.sa_mask);
#ifdef USE_SIGALTSTACK
if (handler == SIG_IGN || handler == SIG_DFL) {
sigact.sa_handler = handler;
sigact.sa_flags = 0;
}
else {
sigact.sa_sigaction = (ruby_sigaction_t*)handler;
sigact.sa_flags = SA_SIGINFO;
}
#else
sigact.sa_handler = handler;
sigact.sa_flags = 0;
#endif
switch (signum) {
#ifdef SA_NOCLDWAIT
case SIGCHLD:
if (handler == SIG_IGN)
sigact.sa_flags |= SA_NOCLDWAIT;
break;
#endif
#if defined(SA_ONSTACK) && defined(USE_SIGALTSTACK)
case SIGSEGV:
#ifdef SIGBUS
case SIGBUS:
#endif
sigact.sa_flags |= SA_ONSTACK;
break;
#endif
}
(void)VALGRIND_MAKE_MEM_DEFINED(&old, sizeof(old));
if (sigaction(signum, &sigact, &old) < 0) {
return SIG_ERR;
}
if (old.sa_flags & SA_SIGINFO)
handler = (sighandler_t)old.sa_sigaction;
else
handler = old.sa_handler;
ASSUME(handler != SIG_ERR);
return handler;
}
sighandler_t
posix_signal(int signum, sighandler_t handler)
{
return ruby_signal(signum, handler);
}
#elif defined _WIN32
static inline sighandler_t
ruby_signal(int signum, sighandler_t handler)
{
if (signum == SIGKILL) {
errno = EINVAL;
return SIG_ERR;
}
return signal(signum, handler);
}
#else /* !POSIX_SIGNAL */
#define ruby_signal(sig,handler) (/* rb_trap_accept_nativethreads[(sig)] = 0,*/ signal((sig),(handler)))
#if 0 /* def HAVE_NATIVETHREAD */
static sighandler_t
ruby_nativethread_signal(int signum, sighandler_t handler)
{
sighandler_t old;
old = signal(signum, handler);
rb_trap_accept_nativethreads[signum] = 1;
return old;
}
#endif
#endif
static int
signal_ignored(int sig)
{
sighandler_t func;
#ifdef POSIX_SIGNAL
struct sigaction old;
(void)VALGRIND_MAKE_MEM_DEFINED(&old, sizeof(old));
if (sigaction(sig, NULL, &old) < 0) return FALSE;
func = old.sa_handler;
#else
sighandler_t old = signal(sig, SIG_DFL);
signal(sig, old);
func = old;
#endif
if (func == SIG_IGN) return 1;
return func == sighandler ? 0 : -1;
}
static void
signal_enque(int sig)
{
ATOMIC_INC(signal_buff.cnt[sig]);
ATOMIC_INC(signal_buff.size);
}
static RETSIGTYPE
sighandler(int sig)
{
int old_errnum = errno;
signal_enque(sig);
rb_thread_wakeup_timer_thread();
#if !defined(BSD_SIGNAL) && !defined(POSIX_SIGNAL)
ruby_signal(sig, sighandler);
#endif
errno = old_errnum;
}
int
rb_signal_buff_size(void)
{
return signal_buff.size;
}
#if HAVE_PTHREAD_H
#include <pthread.h>
#endif
static void
rb_disable_interrupt(void)
{
#ifdef HAVE_PTHREAD_SIGMASK
sigset_t mask;
sigfillset(&mask);
pthread_sigmask(SIG_SETMASK, &mask, NULL);
#endif
}
static void
rb_enable_interrupt(void)
{
#ifdef HAVE_PTHREAD_SIGMASK
sigset_t mask;
sigemptyset(&mask);
pthread_sigmask(SIG_SETMASK, &mask, NULL);
#endif
}
int
rb_get_next_signal(void)
{
int i, sig = 0;
if (signal_buff.size != 0) {
for (i=1; i<RUBY_NSIG; i++) {
if (signal_buff.cnt[i] > 0) {
ATOMIC_DEC(signal_buff.cnt[i]);
ATOMIC_DEC(signal_buff.size);
sig = i;
break;
}
}
}
return sig;
}
#if defined SIGSEGV || defined SIGBUS || defined SIGILL || defined SIGFPE
static const char *received_signal;
# define clear_received_signal() (void)(ruby_disable_gc = 0, received_signal = 0)
#else
# define clear_received_signal() ((void)0)
#endif
#if defined(USE_SIGALTSTACK) || defined(_WIN32)
NORETURN(void rb_ec_stack_overflow(rb_execution_context_t *ec, int crit));
# if defined __HAIKU__
# define USE_UCONTEXT_REG 1
# elif !(defined(HAVE_UCONTEXT_H) && (defined __i386__ || defined __x86_64__ || defined __amd64__))
# elif defined __linux__
# define USE_UCONTEXT_REG 1
# elif defined __APPLE__
# define USE_UCONTEXT_REG 1
# elif defined __FreeBSD__
# define USE_UCONTEXT_REG 1
# endif
#if defined(HAVE_PTHREAD_SIGMASK)
# define ruby_sigunmask pthread_sigmask
#elif defined(HAVE_SIGPROCMASK)
# define ruby_sigunmask sigprocmask
#endif
static void
reset_sigmask(int sig)
{
#if defined(ruby_sigunmask)
sigset_t mask;
#endif
clear_received_signal();
#if defined(ruby_sigunmask)
sigemptyset(&mask);
sigaddset(&mask, sig);
if (ruby_sigunmask(SIG_UNBLOCK, &mask, NULL)) {
rb_bug_errno(STRINGIZE(ruby_sigunmask)":unblock", errno);
}
#endif
}
# ifdef USE_UCONTEXT_REG
static void
check_stack_overflow(int sig, const uintptr_t addr, const ucontext_t *ctx)
{
const DEFINE_MCONTEXT_PTR(mctx, ctx);
# if defined __linux__
# if defined REG_RSP
const greg_t sp = mctx->gregs[REG_RSP];
const greg_t bp = mctx->gregs[REG_RBP];
# else
const greg_t sp = mctx->gregs[REG_ESP];
const greg_t bp = mctx->gregs[REG_EBP];
# endif
# elif defined __APPLE__
# if defined(__LP64__)
const uintptr_t sp = mctx->__ss.__rsp;
const uintptr_t bp = mctx->__ss.__rbp;
# else
const uintptr_t sp = mctx->__ss.__esp;
const uintptr_t bp = mctx->__ss.__ebp;
# endif
# elif defined __FreeBSD__
# if defined(__amd64__)
const __register_t sp = mctx->mc_rsp;
const __register_t bp = mctx->mc_rbp;
# else
const __register_t sp = mctx->mc_esp;
const __register_t bp = mctx->mc_ebp;
# endif
# elif defined __HAIKU__
# if defined(__amd64__)
const unsigned long sp = mctx->rsp;
const unsigned long bp = mctx->rbp;
# else
const unsigned long sp = mctx->esp;
const unsigned long bp = mctx->ebp;
# endif
# endif
enum {pagesize = 4096};
const uintptr_t sp_page = (uintptr_t)sp / pagesize;
const uintptr_t bp_page = (uintptr_t)bp / pagesize;
const uintptr_t fault_page = addr / pagesize;
/* SP in ucontext is not decremented yet when `push` failed, so
* the fault page can be the next. */
if (sp_page == fault_page || sp_page == fault_page + 1 ||
sp_page <= fault_page && fault_page <= bp_page) {
rb_execution_context_t *ec = GET_EC();
int crit = FALSE;
if ((uintptr_t)ec->tag->buf / pagesize <= fault_page + 1) {
/* drop the last tag if it is close to the fault,
* otherwise it can cause stack overflow again at the same
* place. */
ec->tag = ec->tag->prev;
crit = TRUE;
}
reset_sigmask(sig);
rb_ec_stack_overflow(ec, crit);
}
}
# else
static void
check_stack_overflow(int sig, const void *addr)
{
int ruby_stack_overflowed_p(const rb_thread_t *, const void *);
rb_thread_t *th = GET_THREAD();
if (ruby_stack_overflowed_p(th, addr)) {
reset_sigmask(sig);
rb_ec_stack_overflow(th->ec, FALSE);
}
}
# endif
# ifdef _WIN32
# define CHECK_STACK_OVERFLOW() check_stack_overflow(sig, 0)
# else
# define FAULT_ADDRESS info->si_addr
# ifdef USE_UCONTEXT_REG
# define CHECK_STACK_OVERFLOW() check_stack_overflow(sig, (uintptr_t)FAULT_ADDRESS, ctx)
# else
# define CHECK_STACK_OVERFLOW() check_stack_overflow(sig, FAULT_ADDRESS)
# endif
# define MESSAGE_FAULT_ADDRESS " at %p", FAULT_ADDRESS
# endif
#else
# define CHECK_STACK_OVERFLOW() (void)0
#endif
#ifndef MESSAGE_FAULT_ADDRESS
# define MESSAGE_FAULT_ADDRESS
#endif
#if defined SIGSEGV || defined SIGBUS || defined SIGILL || defined SIGFPE
NOINLINE(static void check_reserved_signal_(const char *name, size_t name_len));
/* noinine to reduce stack usage in signal handers */
#define check_reserved_signal(name) check_reserved_signal_(name, sizeof(name)-1)
#ifdef SIGBUS
NORETURN(static ruby_sigaction_t sigbus);
static RETSIGTYPE
sigbus(int sig SIGINFO_ARG)
{
check_reserved_signal("BUS");
/*
* Mac OS X makes KERN_PROTECTION_FAILURE when thread touch guard page.
* and it's delivered as SIGBUS instead of SIGSEGV to userland. It's crazy
* wrong IMHO. but anyway we have to care it. Sigh.
*/
/* Seems Linux also delivers SIGBUS. */
#if defined __APPLE__ || defined __linux__
CHECK_STACK_OVERFLOW();
#endif
rb_bug_context(SIGINFO_CTX, "Bus Error" MESSAGE_FAULT_ADDRESS);
}
#endif
NORETURN(static void ruby_abort(void));
static void
ruby_abort(void)
{
#ifdef __sun
/* Solaris's abort() is async signal unsafe. Of course, it is not
* POSIX compliant.
*/
raise(SIGABRT);
#else
abort();
#endif
}
#ifdef SIGSEGV
NORETURN(static ruby_sigaction_t sigsegv);
static RETSIGTYPE
sigsegv(int sig SIGINFO_ARG)
{
check_reserved_signal("SEGV");
CHECK_STACK_OVERFLOW();
rb_bug_context(SIGINFO_CTX, "Segmentation fault" MESSAGE_FAULT_ADDRESS);
}
#endif
#ifdef SIGILL
NORETURN(static ruby_sigaction_t sigill);
static RETSIGTYPE
sigill(int sig SIGINFO_ARG)
{
check_reserved_signal("ILL");
#if defined __APPLE__
CHECK_STACK_OVERFLOW();
#endif
rb_bug_context(SIGINFO_CTX, "Illegal instruction" MESSAGE_FAULT_ADDRESS);
}
#endif
static void
check_reserved_signal_(const char *name, size_t name_len)
{
const char *prev = ATOMIC_PTR_EXCHANGE(received_signal, name);
if (prev) {
ssize_t RB_UNUSED_VAR(err);
#define NOZ(name, str) name[sizeof(str)-1] = str
static const char NOZ(msg1, " received in ");
static const char NOZ(msg2, " handler\n");
#ifdef HAVE_WRITEV
struct iovec iov[4];
iov[0].iov_base = (void *)name;
iov[0].iov_len = name_len;
iov[1].iov_base = (void *)msg1;
iov[1].iov_len = sizeof(msg1);
iov[2].iov_base = (void *)prev;
iov[2].iov_len = strlen(prev);
iov[3].iov_base = (void *)msg2;
iov[3].iov_len = sizeof(msg2);
err = writev(2, iov, 4);
#else
err = write(2, name, name_len);
err = write(2, msg1, sizeof(msg1));
err = write(2, prev, strlen(prev));
err = write(2, msg2, sizeof(msg2));
#endif
ruby_abort();
}
ruby_disable_gc = 1;
}
#endif
#if defined SIGPIPE || defined SIGSYS
static RETSIGTYPE
sig_do_nothing(int sig)
{
}
#endif
static void
signal_exec(VALUE cmd, int safe, int sig)
{
rb_execution_context_t *ec = GET_EC();
volatile unsigned long old_interrupt_mask = ec->interrupt_mask;
enum ruby_tag_type state;
/*
* workaround the following race:
* 1. signal_enque queues signal for execution
* 2. user calls trap(sig, "IGNORE"), setting SIG_IGN
* 3. rb_signal_exec runs on queued signal
*/
if (IMMEDIATE_P(cmd))
return;
ec->interrupt_mask |= TRAP_INTERRUPT_MASK;
EC_PUSH_TAG(ec);
if ((state = EC_EXEC_TAG()) == TAG_NONE) {
VALUE signum = INT2NUM(sig);
rb_eval_cmd(cmd, rb_ary_new3(1, signum), safe);
}
EC_POP_TAG();
ec = GET_EC();
ec->interrupt_mask = old_interrupt_mask;
if (state) {
/* XXX: should be replaced with rb_threadptr_pending_interrupt_enque() */
EC_JUMP_TAG(ec, state);
}
}
void
rb_trap_exit(void)
{
rb_vm_t *vm = GET_VM();
VALUE trap_exit = vm->trap_list.cmd[0];
if (trap_exit) {
vm->trap_list.cmd[0] = 0;
signal_exec(trap_exit, vm->trap_list.safe[0], 0);
}
}
void
rb_signal_exec(rb_thread_t *th, int sig)
{
rb_vm_t *vm = GET_VM();
VALUE cmd = vm->trap_list.cmd[sig];
int safe = vm->trap_list.safe[sig];
if (cmd == 0) {
switch (sig) {
case SIGINT:
rb_interrupt();
break;
#ifdef SIGHUP
case SIGHUP:
#endif
#ifdef SIGQUIT
case SIGQUIT:
#endif
#ifdef SIGTERM
case SIGTERM:
#endif
#ifdef SIGALRM
case SIGALRM:
#endif
#ifdef SIGUSR1
case SIGUSR1:
#endif
#ifdef SIGUSR2
case SIGUSR2:
#endif
rb_threadptr_signal_raise(th, sig);
break;
}
}
else if (cmd == Qundef) {
rb_threadptr_signal_exit(th);
}
else {
signal_exec(cmd, safe, sig);
}
}
static sighandler_t
default_handler(int sig)
{
sighandler_t func;
switch (sig) {
case SIGINT:
#ifdef SIGHUP
case SIGHUP:
#endif
#ifdef SIGQUIT
case SIGQUIT:
#endif
#ifdef SIGTERM
case SIGTERM:
#endif
#ifdef SIGALRM
case SIGALRM:
#endif
#ifdef SIGUSR1
case SIGUSR1:
#endif
#ifdef SIGUSR2
case SIGUSR2:
#endif
func = sighandler;
break;
#ifdef SIGBUS
case SIGBUS:
func = (sighandler_t)sigbus;
break;
#endif
#ifdef SIGSEGV
case SIGSEGV:
func = (sighandler_t)sigsegv;
break;
#endif
#ifdef SIGPIPE
case SIGPIPE:
func = sig_do_nothing;
break;
#endif
#ifdef SIGSYS
case SIGSYS:
func = sig_do_nothing;
break;
#endif
default:
func = SIG_DFL;
break;
}
return func;
}
static sighandler_t
trap_handler(VALUE *cmd, int sig)
{
sighandler_t func = sighandler;
VALUE command;
if (NIL_P(*cmd)) {
func = SIG_IGN;
}
else {
command = rb_check_string_type(*cmd);
if (NIL_P(command) && SYMBOL_P(*cmd)) {
command = rb_sym2str(*cmd);
if (!command) rb_raise(rb_eArgError, "bad handler");
}
if (!NIL_P(command)) {
const char *cptr;
long len;
SafeStringValue(command); /* taint check */
*cmd = command;
RSTRING_GETMEM(command, cptr, len);
switch (len) {
case 0:
goto sig_ign;
break;
case 14:
if (memcmp(cptr, "SYSTEM_DEFAULT", 14) == 0) {
func = SIG_DFL;
*cmd = 0;
}
break;
case 7:
if (memcmp(cptr, "SIG_IGN", 7) == 0) {
sig_ign:
func = SIG_IGN;
*cmd = Qtrue;
}
else if (memcmp(cptr, "SIG_DFL", 7) == 0) {
sig_dfl:
func = default_handler(sig);
*cmd = 0;
}
else if (memcmp(cptr, "DEFAULT", 7) == 0) {
goto sig_dfl;
}
break;
case 6:
if (memcmp(cptr, "IGNORE", 6) == 0) {
goto sig_ign;
}
break;
case 4:
if (memcmp(cptr, "EXIT", 4) == 0) {
*cmd = Qundef;
}
break;
}
}
else {
rb_proc_t *proc;
GetProcPtr(*cmd, proc);
(void)proc;
}
}
return func;
}
static int
trap_signm(VALUE vsig)
{
int sig = -1;
if (FIXNUM_P(vsig)) {
sig = FIX2INT(vsig);
if (sig < 0 || sig >= NSIG) {
rb_raise(rb_eArgError, "invalid signal number (%d)", sig);
}
}
else {
sig = signm2signo(&vsig, FALSE, TRUE, NULL);
}
return sig;
}
static VALUE
trap(int sig, sighandler_t func, VALUE command)
{
sighandler_t oldfunc;
VALUE oldcmd;
rb_vm_t *vm = GET_VM();
/*
* Be careful. ruby_signal() and trap_list.cmd[sig] must be changed
* atomically. In current implementation, we only need to don't call
* RUBY_VM_CHECK_INTS().
*/
if (sig == 0) {
oldfunc = SIG_ERR;
}
else {
oldfunc = ruby_signal(sig, func);
if (oldfunc == SIG_ERR) rb_sys_fail_str(rb_signo2signm(sig));
}
oldcmd = vm->trap_list.cmd[sig];
switch (oldcmd) {
case 0:
case Qtrue:
if (oldfunc == SIG_IGN) oldcmd = rb_str_new2("IGNORE");
else if (oldfunc == SIG_DFL) oldcmd = rb_str_new2("SYSTEM_DEFAULT");
else if (oldfunc == sighandler) oldcmd = rb_str_new2("DEFAULT");
else oldcmd = Qnil;
break;
case Qnil:
break;
case Qundef:
oldcmd = rb_str_new2("EXIT");
break;
}
vm->trap_list.cmd[sig] = command;
vm->trap_list.safe[sig] = rb_safe_level();
return oldcmd;
}
static int
reserved_signal_p(int signo)
{
/* Synchronous signal can't deliver to main thread */
#ifdef SIGSEGV
if (signo == SIGSEGV)
return 1;
#endif
#ifdef SIGBUS
if (signo == SIGBUS)
return 1;
#endif
#ifdef SIGILL
if (signo == SIGILL)
return 1;
#endif
#ifdef SIGFPE
if (signo == SIGFPE)
return 1;
#endif
/* used ubf internal see thread_pthread.c. */
#ifdef SIGVTALRM
if (signo == SIGVTALRM)
return 1;
#endif
return 0;
}
/*
* call-seq:
* Signal.trap( signal, command ) -> obj
* Signal.trap( signal ) {| | block } -> obj
*
* Specifies the handling of signals. The first parameter is a signal
* name (a string such as ``SIGALRM'', ``SIGUSR1'', and so on) or a
* signal number. The characters ``SIG'' may be omitted from the
* signal name. The command or block specifies code to be run when the
* signal is raised.
* If the command is the string ``IGNORE'' or ``SIG_IGN'', the signal
* will be ignored.
* If the command is ``DEFAULT'' or ``SIG_DFL'', the Ruby's default handler
* will be invoked.
* If the command is ``EXIT'', the script will be terminated by the signal.
* If the command is ``SYSTEM_DEFAULT'', the operating system's default
* handler will be invoked.
* Otherwise, the given command or block will be run.
* The special signal name ``EXIT'' or signal number zero will be
* invoked just prior to program termination.
* trap returns the previous handler for the given signal.
*
* Signal.trap(0, proc { puts "Terminating: #{$$}" })
* Signal.trap("CLD") { puts "Child died" }
* fork && Process.wait
*
* produces:
* Terminating: 27461
* Child died
* Terminating: 27460
*/
static VALUE
sig_trap(int argc, VALUE *argv)
{
int sig;
sighandler_t func;
VALUE cmd;
rb_check_arity(argc, 1, 2);
sig = trap_signm(argv[0]);
if (reserved_signal_p(sig)) {
const char *name = signo2signm(sig);
if (name)
rb_raise(rb_eArgError, "can't trap reserved signal: SIG%s", name);
else
rb_raise(rb_eArgError, "can't trap reserved signal: %d", sig);
}
if (argc == 1) {
cmd = rb_block_proc();
func = sighandler;
}
else {
cmd = argv[1];
func = trap_handler(&cmd, sig);
}
if (OBJ_TAINTED(cmd)) {
rb_raise(rb_eSecurityError, "Insecure: tainted signal trap");
}
return trap(sig, func, cmd);
}
/*
* call-seq:
* Signal.list -> a_hash
*
* Returns a list of signal names mapped to the corresponding
* underlying signal numbers.
*
* Signal.list #=> {"EXIT"=>0, "HUP"=>1, "INT"=>2, "QUIT"=>3, "ILL"=>4, "TRAP"=>5, "IOT"=>6, "ABRT"=>6, "FPE"=>8, "KILL"=>9, "BUS"=>7, "SEGV"=>11, "SYS"=>31, "PIPE"=>13, "ALRM"=>14, "TERM"=>15, "URG"=>23, "STOP"=>19, "TSTP"=>20, "CONT"=>18, "CHLD"=>17, "CLD"=>17, "TTIN"=>21, "TTOU"=>22, "IO"=>29, "XCPU"=>24, "XFSZ"=>25, "VTALRM"=>26, "PROF"=>27, "WINCH"=>28, "USR1"=>10, "USR2"=>12, "PWR"=>30, "POLL"=>29}
*/
static VALUE
sig_list(void)
{
VALUE h = rb_hash_new();
const struct signals *sigs;
for (sigs = siglist; sigs->signm; sigs++) {
rb_hash_aset(h, rb_fstring_cstr(sigs->signm), INT2FIX(sigs->signo));
}
return h;
}
#define INSTALL_SIGHANDLER(cond, signame, signum) do { \
static const char failed[] = "failed to install "signame" handler"; \
if (!(cond)) break; \
if (reserved_signal_p(signum)) rb_bug(failed); \
perror(failed); \
} while (0)
static int
install_sighandler(int signum, sighandler_t handler)
{
sighandler_t old;
old = ruby_signal(signum, handler);
if (old == SIG_ERR) return -1;
/* signal handler should be inherited during exec. */
if (old != SIG_DFL) {
ruby_signal(signum, old);
}
return 0;
}
# define install_sighandler(signum, handler) \
INSTALL_SIGHANDLER(install_sighandler(signum, handler), #signum, signum)
#if defined(SIGCLD) || defined(SIGCHLD)
static int
init_sigchld(int sig)
{
sighandler_t oldfunc;
oldfunc = ruby_signal(sig, SIG_DFL);
if (oldfunc == SIG_ERR) return -1;
if (oldfunc != SIG_DFL && oldfunc != SIG_IGN) {
ruby_signal(sig, oldfunc);
}
else {
GET_VM()->trap_list.cmd[sig] = 0;
}
return 0;
}
# define init_sigchld(signum) \
INSTALL_SIGHANDLER(init_sigchld(signum), #signum, signum)
#endif
void
ruby_sig_finalize(void)
{
sighandler_t oldfunc;
oldfunc = ruby_signal(SIGINT, SIG_IGN);
if (oldfunc == sighandler) {
ruby_signal(SIGINT, SIG_DFL);
}
}
int ruby_enable_coredump = 0;
/*
* Many operating systems allow signals to be sent to running
* processes. Some signals have a defined effect on the process, while
* others may be trapped at the code level and acted upon. For
* example, your process may trap the USR1 signal and use it to toggle
* debugging, and may use TERM to initiate a controlled shutdown.
*
* pid = fork do
* Signal.trap("USR1") do
* $debug = !$debug
* puts "Debug now: #$debug"
* end
* Signal.trap("TERM") do
* puts "Terminating..."
* shutdown()
* end
* # . . . do some work . . .
* end
*
* Process.detach(pid)
*
* # Controlling program:
* Process.kill("USR1", pid)
* # ...
* Process.kill("USR1", pid)
* # ...
* Process.kill("TERM", pid)
*
* produces:
* Debug now: true
* Debug now: false
* Terminating...
*
* The list of available signal names and their interpretation is
* system dependent. Signal delivery semantics may also vary between
* systems; in particular signal delivery may not always be reliable.
*/
void
Init_signal(void)
{
VALUE mSignal = rb_define_module("Signal");
rb_define_global_function("trap", sig_trap, -1);
rb_define_module_function(mSignal, "trap", sig_trap, -1);
rb_define_module_function(mSignal, "list", sig_list, 0);
rb_define_module_function(mSignal, "signame", sig_signame, 1);
rb_define_method(rb_eSignal, "initialize", esignal_init, -1);
rb_define_method(rb_eSignal, "signo", esignal_signo, 0);
rb_alias(rb_eSignal, rb_intern_const("signm"), rb_intern_const("message"));
rb_define_method(rb_eInterrupt, "initialize", interrupt_init, -1);
/* At this time, there is no subthread. Then sigmask guarantee atomics. */
rb_disable_interrupt();
install_sighandler(SIGINT, sighandler);
#ifdef SIGHUP
install_sighandler(SIGHUP, sighandler);
#endif
#ifdef SIGQUIT
install_sighandler(SIGQUIT, sighandler);
#endif
#ifdef SIGTERM
install_sighandler(SIGTERM, sighandler);
#endif
#ifdef SIGALRM
install_sighandler(SIGALRM, sighandler);
#endif
#ifdef SIGUSR1
install_sighandler(SIGUSR1, sighandler);
#endif
#ifdef SIGUSR2
install_sighandler(SIGUSR2, sighandler);
#endif
if (!ruby_enable_coredump) {
#ifdef SIGBUS
install_sighandler(SIGBUS, (sighandler_t)sigbus);
#endif
#ifdef SIGILL
install_sighandler(SIGILL, (sighandler_t)sigill);
#endif
#ifdef SIGSEGV
RB_ALTSTACK_INIT(GET_VM()->main_altstack);
install_sighandler(SIGSEGV, (sighandler_t)sigsegv);
#endif
}
#ifdef SIGPIPE
install_sighandler(SIGPIPE, sig_do_nothing);
#endif
#ifdef SIGSYS
install_sighandler(SIGSYS, sig_do_nothing);
#endif
#if defined(SIGCLD)
init_sigchld(SIGCLD);
#elif defined(SIGCHLD)
init_sigchld(SIGCHLD);
#endif
rb_enable_interrupt();
}
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