unrevert r63852 but keep SIGCHLD path disabled for win32

Reading win32/win32.c waitpid implementation, maybe waitpid(-1, ...)
on that platform will never conflict with mjit use of waitpid.

In any case, I've added WAITPID_USE_SIGCHLD macro to vm_core.h
so it can be easy for Linux/BSD users to test (hopefully!)
win32-compatible code.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63855 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

configure.ac

@@ -766,6 +766,7 @@ AS_CASE(["$target_os"],
 		AS_IF([test $gcc_major -lt 4 -o \( $gcc_major -eq 4 -a $gcc_minor -lt 3 \)], [
 		    ac_cv_func___builtin_setjmp=no
 		])
+		with_setjmp_type=sigsetjmp # to hijack SIGCHLD handler
 		AC_CACHE_CHECK(for broken crypt with 8bit chars, rb_cv_broken_crypt,
 		    [AC_TRY_RUN([
 #include <stdio.h>
@@ -1782,6 +1783,7 @@ AC_CHECK_FUNCS(getsid)
 AC_CHECK_FUNCS(gettimeofday)		# for making ac_cv_func_gettimeofday
 AC_CHECK_FUNCS(getuidx)
 AC_CHECK_FUNCS(gmtime_r)
+AC_CHECK_FUNCS(grantpt)
 AC_CHECK_FUNCS(initgroups)
 AC_CHECK_FUNCS(ioctl)
 AC_CHECK_FUNCS(isfinite)

ext/pty/pty.c

@@ -246,19 +246,13 @@ get_device_once(int *master, int *slave, char SlaveName[DEVICELEN], int nomesg,
     /* Unix98 PTY */
     int masterfd = -1, slavefd = -1;
     char *slavedevice;
-    struct sigaction dfl, old;
-
-    dfl.sa_handler = SIG_DFL;
-    dfl.sa_flags = 0;
-    sigemptyset(&dfl.sa_mask);
 
 #if defined(__sun) || (defined(__FreeBSD__) && __FreeBSD_version < 902000)
     /* workaround for Solaris 10: grantpt() doesn't work if FD_CLOEXEC is set.  [ruby-dev:44688] */
     /* FreeBSD 9.2 or later supports O_CLOEXEC
      * http://www.freebsd.org/cgi/query-pr.cgi?pr=162374 */
     if ((masterfd = posix_openpt(O_RDWR|O_NOCTTY)) == -1) goto error;
-    if (sigaction(SIGCHLD, &dfl, &old) == -1) goto error;
-    if (grantpt(masterfd) == -1) goto grantpt_error;
+    if (rb_grantpt(masterfd) == -1) goto error;
     rb_fd_fix_cloexec(masterfd);
 #else
     {
@@ -272,10 +266,8 @@ get_device_once(int *master, int *slave, char SlaveName[DEVICELEN], int nomesg,
 	if ((masterfd = posix_openpt(flags)) == -1) goto error;
     }
     rb_fd_fix_cloexec(masterfd);
-    if (sigaction(SIGCHLD, &dfl, &old) == -1) goto error;
-    if (grantpt(masterfd) == -1) goto grantpt_error;
+    if (rb_grantpt(masterfd) == -1) goto error;
 #endif
-    if (sigaction(SIGCHLD, &old, NULL) == -1) goto error;
     if (unlockpt(masterfd) == -1) goto error;
     if ((slavedevice = ptsname(masterfd)) == NULL) goto error;
     if (no_mesg(slavedevice, nomesg) == -1) goto error;
@@ -293,8 +285,6 @@ get_device_once(int *master, int *slave, char SlaveName[DEVICELEN], int nomesg,
     strlcpy(SlaveName, slavedevice, DEVICELEN);
     return 0;
 
-  grantpt_error:
-    sigaction(SIGCHLD, &old, NULL);
   error:
     if (slavefd != -1) close(slavefd);
     if (masterfd != -1) close(masterfd);
@@ -346,21 +336,17 @@ get_device_once(int *master, int *slave, char SlaveName[DEVICELEN], int nomesg,
 
     extern char *ptsname(int);
     extern int unlockpt(int);
-    extern int grantpt(int);
 
 #if defined(__sun)
     /* workaround for Solaris 10: grantpt() doesn't work if FD_CLOEXEC is set.  [ruby-dev:44688] */
     if((masterfd = open("/dev/ptmx", O_RDWR, 0)) == -1) goto error;
-    s = signal(SIGCHLD, SIG_DFL);
-    if(grantpt(masterfd) == -1) goto error;
+    if(rb_grantpt(masterfd) == -1) goto error;
     rb_fd_fix_cloexec(masterfd);
 #else
     if((masterfd = rb_cloexec_open("/dev/ptmx", O_RDWR, 0)) == -1) goto error;
     rb_update_max_fd(masterfd);
-    s = signal(SIGCHLD, SIG_DFL);
-    if(grantpt(masterfd) == -1) goto error;
+    if(rb_grantpt(masterfd) == -1) goto error;
 #endif
-    signal(SIGCHLD, s);
     if(unlockpt(masterfd) == -1) goto error;
     if((slavedevice = ptsname(masterfd)) == NULL) goto error;
     if (no_mesg(slavedevice, nomesg) == -1) goto error;

internal.h

@@ -2042,6 +2042,9 @@ VALUE rb_gcd_normal(VALUE self, VALUE other);
 VALUE rb_gcd_gmp(VALUE x, VALUE y);
 #endif
 
+/* signal.c (export) */
+int rb_grantpt(int fd);
+
 /* string.c (export) */
 #ifdef RUBY_ENCODING_H
 /* internal use */

mjit.c

@@ -80,6 +80,7 @@
 #include "constant.h"
 #include "id_table.h"
 #include "ruby_assert.h"
+#include "ruby/thread.h"
 #include "ruby/util.h"
 #include "ruby/version.h"
 
@@ -118,6 +119,10 @@ extern void rb_native_cond_wait(rb_nativethread_cond_t *cond, rb_nativethread_lo
 
 extern int rb_thread_create_mjit_thread(void (*child_hook)(void), void (*worker_func)(void));
 
+/* process.c */
+rb_pid_t ruby_waitpid_locked(rb_vm_t *, rb_pid_t, int *status, int options,
+                          rb_nativethread_cond_t *cond);
+
 #define RB_CONDATTR_CLOCK_MONOTONIC 1
 
 #ifdef _WIN32
@@ -263,7 +268,7 @@ real_ms_time(void)
 static int
 sprint_uniq_filename(char *str, size_t size, unsigned long id, const char *prefix, const char *suffix)
 {
-    return snprintf(str, size, "%s/%sp%luu%lu%s", tmp_dir, prefix, (unsigned long) getpid(), id, suffix);
+    return snprintf(str, size, "%s/%sp%"PRI_PIDT_PREFIX"uu%lu%s", tmp_dir, prefix, getpid(), id, suffix);
 }
 
 /* Return an unique file name in /tmp with PREFIX and SUFFIX and
@@ -401,22 +406,41 @@ start_process(const char *path, char *const *argv)
 static int
 exec_process(const char *path, char *const argv[])
 {
-    int stat, exit_code;
+    int stat, exit_code = -2;
     pid_t pid;
+    rb_vm_t *vm = WAITPID_USE_SIGCHLD ? GET_VM() : 0;
+    rb_nativethread_cond_t cond;
 
-    pid = start_process(path, argv);
-    if (pid <= 0)
-        return -2;
+    if (vm) {
+        rb_native_cond_initialize(&cond);
+        rb_native_mutex_lock(&vm->waitpid_lock);
+    }
 
-    for (;;) {
-        waitpid(pid, &stat, 0);
-        if (WIFEXITED(stat)) {
-            exit_code = WEXITSTATUS(stat);
-            break;
-        } else if (WIFSIGNALED(stat)) {
-            exit_code = -1;
+    pid = start_process(path, argv);
+    for (;pid > 0;) {
+        pid_t r = vm ? ruby_waitpid_locked(vm, pid, &stat, 0, &cond)
+                     : waitpid(pid, &stat, 0);
+        if (r == -1) {
+            if (errno == EINTR) continue;
+            fprintf(stderr, "[%"PRI_PIDT_PREFIX"d] waitpid(%"PRI_PIDT_PREFIX"d): %s (SIGCHLD=%d,%u)\n",
+                    getpid(), pid, strerror(errno),
+                    RUBY_SIGCHLD, SIGCHLD_LOSSY);
             break;
         }
+        else if (r == pid) {
+            if (WIFEXITED(stat)) {
+                exit_code = WEXITSTATUS(stat);
+                break;
+            } else if (WIFSIGNALED(stat)) {
+                exit_code = -1;
+                break;
+            }
+        }
+    }
+
+    if (vm) {
+        rb_native_mutex_unlock(&vm->waitpid_lock);
+        rb_native_cond_destroy(&cond);
     }
     return exit_code;
 }
@@ -1491,12 +1515,15 @@ mjit_init(struct mjit_options *opts)
 static void
 stop_worker(void)
 {
+    rb_execution_context_t *ec = GET_EC();
+
     stop_worker_p = TRUE;
     while (!worker_stopped) {
         verbose(3, "Sending cancel signal to worker");
         CRITICAL_SECTION_START(3, "in stop_worker");
         rb_native_cond_broadcast(&mjit_worker_wakeup);
         CRITICAL_SECTION_FINISH(3, "in stop_worker");
+        RUBY_VM_CHECK_INTS(ec);
     }
 }