Make perl fork()-safe (in a slightly limited way) even on

platforms that don't have pthread_atfork() (extension of
the fix in change#11151).

Note that this will not help extensions that call fork()
directly in C, or that link to libraries that call fork()
directly.  Such cases must be fixed to either call
PerlProc_fork(), or call atfork_lock() in parent before the
calling the function that forks and call atfork_unlock()
in both parent and child immediately after the fork().
(There are no worries if C code calls exec() in the child
immediately after a fork().  Only cases where the child
calls perl's API functions (including New()) after the
fork() are problematic.)

This change also eliminates the use of vfork() from perl,
since all such uses were violating the severe restrictions
on modifying the state of the process between the vfork()
and the exec().

This is a modified version of patches suggested by Abhijit
Menon-Sen and Richard Soderberg.

p4raw-link: @11151 on //depot/perl: 50dd6e574ff39b609595ddb16b2fe9f625a26f8c

p4raw-id: //depot/perl@11423

1 files changed, 12 insertions, 0 deletions

diff --git a/objXSUB.h b/objXSUB.h
index 43a10fa4fa..564bd9c4ab 100644
--- a/objXSUB.h
+++ b/objXSUB.h
@@ -909,6 +909,18 @@
 #define Perl_my_fflush_all	pPerl->Perl_my_fflush_all
 #undef  my_fflush_all
 #define my_fflush_all		Perl_my_fflush_all
+#undef  Perl_my_fork
+#define Perl_my_fork		pPerl->Perl_my_fork
+#undef  my_fork
+#define my_fork			Perl_my_fork
+#undef  Perl_atfork_lock
+#define Perl_atfork_lock	pPerl->Perl_atfork_lock
+#undef  atfork_lock
+#define atfork_lock		Perl_atfork_lock
+#undef  Perl_atfork_unlock
+#define Perl_atfork_unlock	pPerl->Perl_atfork_unlock
+#undef  atfork_unlock
+#define atfork_unlock		Perl_atfork_unlock
 #undef  Perl_my_lstat
 #define Perl_my_lstat		pPerl->Perl_my_lstat
 #undef  my_lstat