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ruby--ruby/signal.c
normal 708bfd2115 thread_pthread: remove timer-thread by restructuring GVL 
To reduce resource use and reduce CI failure; remove
timer-thread.  Single-threaded Ruby processes (including forked
children) will never see extra thread overhead.  This prevents
glibc and jemalloc from going into multi-threaded mode and
initializing locks or causing fragmentation via arena explosion.

The GVL is implements its own wait-queue as a ccan/list to
permit controlling wakeup order.  Timeslice under contention is
handled by a designated timer thread (similar to choosing a
"patrol_thread" for current deadlock checking).

There is only one self-pipe, now, as wakeups for timeslice are
done independently using condition variables.  This reduces FD
pressure slightly.

Signal handling is handled directly by a Ruby Thread (instead
of timer-thread) by exposing signal self-pipe to callers of
rb_thread_fd_select, native_sleep, rb_wait_for_single_fd, etc...
Acquiring, using, and releasing the self-pipe is exposed via 4
new internal functions:

1) rb_sigwait_fd_get - exclusively acquire timer_thread_pipe.normal[0]

2) rb_sigwait_fd_sleep - sleep and wait for signal (and no other FDs)

3) rb_sigwait_fd_put - release acquired result from rb_sigwait_fd_get

4) rb_sigwait_fd_migrate - migrate signal handling to another thread
                           after calling rb_sigwait_fd_put.

rb_sigwait_fd_migrate is necessary for waitpid callers because
only one thread can wait on self-pipe at a time, otherwise a
deadlock will occur if threads fight over the self-pipe.

TRAP_INTERRUPT_MASK is now set for the main thread directly in
signal handler via rb_thread_wakeup_timer_thread.

Originally, I wanted to use POSIX timers
(timer_create/timer_settime) for this.  Unfortunately, this
proved unfeasible as Mutex#sleep resumes on spurious wakeups and
test/thread/test_cv.rb::test_condvar_timed_wait failed.  Using
pthread_sigmask to mask out SIGVTALRM fixed that test,  but
test/fiddle/test_function.rb::test_nogvl_poll proved there'd be
some unavoidable (and frequent) incompatibilities from that
approach.

Finally, this allows us to drop thread_destruct_lock and
interrupt current ec directly.

We don't need to rely on vm->thread_destruct_lock or a coherent
vm->running_thread on any platform.  Separate timer-thread for
time slice and signal handling is relegated to thread_win32.c,
now.

[ruby-core:88088] [Misc #14937]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64107 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
2018-07-29 20:47:33 +00:00

1629 lines
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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
#define FOREACH_SIGNAL(sig, offset) \
for (sig = siglist + (offset); sig < siglist + numberof(siglist); ++sig)
enum { LONGEST_SIGNAME = 7 }; /* MIGRATE and RETRACT */
static const struct signals {
char signm[LONGEST_SIGNAME + 1];
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
#if RUBY_SIGCHLD
{"CHLD", RUBY_SIGCHLD },
{"CLD", RUBY_SIGCHLD },
#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
};
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, nmlen;
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;
nmlen = len - prefix;
nm += prefix;
if (nmlen > LONGEST_SIGNAME) goto unsupported;
FOREACH_SIGNAL(sigs, !exit) {
if (memcmp(sigs->signm, nm, nmlen) == 0 &&
sigs->signm[nmlen] == '\0') {
return negative ? -sigs->signo : sigs->signo;
}
}
goto unsupported;
}
static const char*
signo2signm(int no)
{
const struct signals *sigs;
FOREACH_SIGNAL(sigs, 0) {
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;
volatile unsigned int ruby_nocldwait;
#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) {
case SIGCHLD:
if (handler == SIG_IGN) {
ruby_nocldwait = 1;
if (sigact.sa_flags & SA_SIGINFO) {
sigact.sa_sigaction = (ruby_sigaction_t*)sighandler;
}
else {
sigact.sa_handler = sighandler;
}
}
else {
ruby_nocldwait = 0;
}
break;
#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 rb_atomic_t sigchld_hit;
static RETSIGTYPE
sighandler(int sig)
{
int old_errnum = errno;
/* the VM always needs to handle SIGCHLD for rb_waitpid */
if (sig == RUBY_SIGCHLD) {
rb_vm_t *vm = GET_VM();
ATOMIC_EXCHANGE(sigchld_hit, 1);
/* avoid spurious wakeup in main thread iff nobody uses trap(:CHLD) */
if (vm && ACCESS_ONCE(VALUE, vm->trap_list.cmd[sig])) {
signal_enque(sig);
}
}
else {
signal_enque(sig);
}
rb_thread_wakeup_timer_thread(sig);
#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 rb_atomic_t 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 ruby_waitpid_all(rb_vm_t *); /* process.c */
void
ruby_sigchld_handler(rb_vm_t *vm)
{
if (SIGCHLD_LOSSY || ATOMIC_EXCHANGE(sigchld_hit, 0)) {
ruby_waitpid_all(vm);
}
}
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
#if RUBY_SIGCHLD
case RUBY_SIGCHLD:
#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) {
if (sig == RUBY_SIGCHLD) {
goto sig_dfl;
}
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;
}
ACCESS_ONCE(VALUE, 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;
FOREACH_SIGNAL(sigs, 0) {
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 RUBY_SIGCHLD
static int
init_sigchld(int sig)
{
sighandler_t oldfunc;
sighandler_t func = sighandler;
oldfunc = ruby_signal(sig, SIG_DFL);
if (oldfunc == SIG_ERR) return -1;
ruby_signal(sig, func);
ACCESS_ONCE(VALUE, 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 RUBY_SIGCHLD
init_sigchld(RUBY_SIGCHLD);
#endif
rb_enable_interrupt();
}
#if defined(HAVE_GRANTPT)
extern int grantpt(int);
#else
static int
fake_grantfd(int masterfd)
{
errno = ENOSYS;
return -1;
}
#define grantpt(fd) fake_grantfd(fd)
#endif
int
rb_grantpt(int masterfd)
{
if (RUBY_SIGCHLD) {
rb_vm_t *vm = GET_VM();
int ret, e;
/*
* Prevent waitpid calls from Ruby by taking waitpid_lock.
* Pedantically, grantpt(3) is undefined if a non-default
* SIGCHLD handler is defined, but preventing conflicting
* waitpid calls ought to be sufficient.
*
* We could install the default sighandler temporarily, but that
* could cause SIGCHLD to be missed by other threads. Blocking
* SIGCHLD won't work here, either, unless we stop and restart
* timer-thread (as only timer-thread sees SIGCHLD), but that
* seems like overkill.
*/
rb_nativethread_lock_lock(&vm->waitpid_lock);
{
ret = grantpt(masterfd); /* may spawn `pt_chown' and wait on it */
if (ret < 0) e = errno;
}
rb_nativethread_lock_unlock(&vm->waitpid_lock);
if (ret < 0) errno = e;
return ret;
}
else {
return grantpt(masterfd);
}
}
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