From: Tanaka Akira <akr@...17n.org>
Date: 2005-07-23T00:55:09+09:00
Subject: Re: [BUG] Segmentation fault with a threads/forks script

In article <TYOMLEM041XvpFVjCRG000000c1@tyomlvem02.e2k.ad.ge.com>,
  nobuyoshi nakada <nobuyoshi.nakada@ge.com> writes:

> It seems to have new related bug(s), I'll investigate it more.

The all three fd_sets must be long enough for select.

Index: eval.c
===================================================================
RCS file: /src/ruby/eval.c,v
retrieving revision 1.803
diff -u -r1.803 eval.c
--- eval.c	19 Jul 2005 14:57:47 -0000	1.803
+++ eval.c	22 Jul 2005 15:49:31 -0000
@@ -9880,10 +9880,8 @@
     }
 }
 
-void
-rb_fd_set(n, fds)
-    int n;
-    rb_fdset_t *fds;
+static void
+rb_fd_resize(int n, rb_fdset_t *fds)
 {
     int m = howmany(n + 1, NFDBITS) * sizeof(fd_mask);
     int o = howmany(fds->maxfd, NFDBITS) * sizeof(fd_mask);
@@ -9896,6 +9894,14 @@
 	memset((char *)fds->fdset + o, 0, m - o);
     }
     if (n >= fds->maxfd) fds->maxfd = n + 1;
+}
+
+void
+rb_fd_set(n, fds)
+    int n;
+    rb_fdset_t *fds;
+{
+    rb_fd_resize(n, fds);
     FD_SET(n, fds->fdset);
 }
 
@@ -9931,6 +9937,15 @@
     memcpy(dst->fdset, src, size);
 }
 
+int
+rb_fd_select(int n, rb_fdset_t *readfds, rb_fdset_t *writefds, rb_fdset_t *exceptfds, struct timeval *timeout)
+{
+    rb_fd_resize(n-1, readfds);
+    rb_fd_resize(n-1, writefds);
+    rb_fd_resize(n-1, exceptfds);
+    return select(n, rb_fd_ptr(readfds), rb_fd_ptr(writefds), rb_fd_ptr(exceptfds), timeout);
+}
+
 #undef FD_ZERO
 #undef FD_SET
 #undef FD_CLR
@@ -10795,7 +10810,7 @@
 	    delay_ptr = &delay_tv;
 	}
 
-	n = select(max+1, rb_fd_ptr(&readfds), rb_fd_ptr(&writefds), rb_fd_ptr(&exceptfds), delay_ptr);
+	n = rb_fd_select(max+1, &readfds, &writefds, &exceptfds, delay_ptr);
 	if (n < 0) {
 	    int e = errno;
 
Index: intern.h
===================================================================
RCS file: /src/ruby/intern.h,v
retrieving revision 1.172
diff -u -r1.172 intern.h
--- intern.h	14 Jul 2005 15:11:52 -0000	1.172
+++ intern.h	22 Jul 2005 15:49:32 -0000
@@ -162,6 +162,7 @@
 void rb_fd_clr _((int, rb_fdset_t *));
 int rb_fd_isset _((int, const rb_fdset_t *));
 void rb_fd_copy _((rb_fdset_t *, const fd_set *, int));
+int rb_fd_select(int, rb_fdset_t *, rb_fdset_t *, rb_fdset_t *, struct timeval *);
 
 #define rb_fd_ptr(f)	((f)->fdset)
 #define rb_fd_max(f)	((f)->maxfd)
@@ -178,6 +179,7 @@
 #define rb_fd_init(f)	FD_ZERO(f)
 #define rb_fd_term(f)	(f)
 #define rb_fd_max(f)	FD_SETSIZE
+#define rb_fd_select(n, rfds, wfds, efds, timeout)	select(n, rfds, wfds, efds, timeout)
 
 #endif
 
-- 
Tanaka Akira