don't allow SIGCHLD to be ignored at startup, or wait*() and

$? break

p4raw-id: //depot/perl@4440

3 files changed, 44 insertions, 10 deletions

diff --git a/perl.c b/perl.c
index d5b6d43349..71b3b94e10 100644
--- a/perl.c
+++ b/perl.c
@@ -201,6 +201,7 @@ perl_construct(pTHXx)
 
     init_i18nl10n(1);
     SET_NUMERIC_STANDARD();
+
 #if defined(PERL_SUBVERSION) && PERL_SUBVERSION > 0
     sprintf(PL_patchlevel, "%7.5f",   (double) PERL_REVISION
 				+ ((double) PERL_VERSION / (double) 1000)
@@ -942,6 +943,21 @@ print \"  \\@INC:\\n    @INC\\n\";");
 
     validate_suid(validarg, scriptname,fdscript);
 
+#if defined(SIGCHLD) || defined(SIGCLD)
+    {
+#ifndef SIGCHLD
+#  define SIGCHLD SIGCLD
+#endif
+	Sighandler_t sigstate = rsignal_state(SIGCHLD);
+	if (sigstate == SIG_IGN) {
+	    if (ckWARN(WARN_SIGNAL))
+		Perl_warner(aTHX_ WARN_SIGNAL,
+			    "Can't ignore signal CHLD, forcing to default");
+	    (void)rsignal(SIGCHLD, (Sighandler_t)SIG_DFL);
+	}
+    }
+#endif
+
     if (PL_doextract)
 	find_beginning();
 
diff --git a/pod/perldelta.pod b/pod/perldelta.pod
index 0c7a0c7c91..6344ee4f9a 100644
--- a/pod/perldelta.pod
+++ b/pod/perldelta.pod
@@ -1404,16 +1404,6 @@ See L<perlfunc/pack>.
 but this did not follow some numeric unpack specification.
 See L<perlfunc/pack>.
 
-=item Repeat count in pack overflows
-
-(F) You can't specify a repeat count so large that it overflows
-your signed integers.  See L<perlfunc/pack>.
-
-=item Repeat count in unpack overflows
-
-(F) You can't specify a repeat count so large that it overflows
-your signed integers.  See L<perlfunc/unpack>.
-
 =item /%s/: Unrecognized escape \\%c passed through
 
 (W) You used a backslash-character combination which is not recognized
@@ -1504,6 +1494,15 @@ so it was truncated to the string shown.
 
 (P) For some reason you can't check the filesystem of the script for nosuid.
 
+=item Can't ignore signal CHLD, forcing to default
+
+(W) Perl has detected that it is being run with the SIGCHLD signal
+(sometimes known as SIGCLD) disabled.  Since disabling this signal
+will interfere with proper determination of exit status of child
+processes, Perl has reset the signal to its default value.
+This situation typically indicates that the parent program under
+which Perl may be running (e.g. cron) is being very careless.
+
 =item Can't modify non-lvalue subroutine call
 
 (F) Subroutines meant to be used in lvalue context should be declared as
@@ -1746,6 +1745,16 @@ could be a potential Year 2000 problem.
 
 See Server error.
 
+=item Repeat count in pack overflows
+
+(F) You can't specify a repeat count so large that it overflows
+your signed integers.  See L<perlfunc/pack>.
+
+=item Repeat count in unpack overflows
+
+(F) You can't specify a repeat count so large that it overflows
+your signed integers.  See L<perlfunc/unpack>.
+
 =item realloc() of freed memory ignored
 
 (S) An internal routine called realloc() on something that had already
diff --git a/pod/perldiag.pod b/pod/perldiag.pod
index a6a723cc86..18abdea7e1 100644
--- a/pod/perldiag.pod
+++ b/pod/perldiag.pod
@@ -826,6 +826,15 @@ L<perlfunc/goto>.
 (F) The "goto subroutine" call can't be used to jump out of an eval "string".
 (You can use it to jump out of an eval {BLOCK}, but you probably don't want to.)
 
+=item Can't ignore signal CHLD, forcing to default
+
+(W) Perl has detected that it is being run with the SIGCHLD signal
+(sometimes known as SIGCLD) disabled.  Since disabling this signal
+will interfere with proper determination of exit status of child
+processes, Perl has reset the signal to its default value.
+This situation typically indicates that the parent program under
+which Perl may be running (e.g. cron) is being very careless.
+
 =item Can't localize through a reference
 
 (F) You said something like C<local $$ref>, which Perl can't currently