[ruby-dev:25004] Re: IO#flush dumps core again

なかだです。

At Tue, 30 Nov 2004 23:59:59 +0900,
Tanaka Akira wrote in [ruby-dev:25003]:
> 次のようにすると core を吐きます。
> 
> % ./ruby -ve '
> r, w = IO.pipe
> w.sync = false
> w << "a" * 4096
> w.flush
> pid = fork {
>   w.close
>   sleep 0.1
>   Process.kill("USR1", Process.ppid)
>   r.sysread(4096)
>   sleep 0.1
>   r.sysread(1000)
> }
> r.close
> w << "b"
> trap("USR1") { callcc {|k| $k = k } }
> w.flush
> w.close
> $k.call
> '
> ruby 1.9.0 (2004-11-30) [i686-linux]
> -e:17: [BUG] Segmentation fault
> ruby 1.9.0 (2004-11-30) [i686-linux]

IO#flushの問題というよりは、trapを跨いだContinuationの呼び出し
が問題だと思うんですが、あってるでしょうか。

かなり苦し紛れですが。


Index: eval.c
===================================================================
RCS file: /cvs/ruby/src/ruby/eval.c,v
retrieving revision 1.737
diff -U2 -p -d -r1.737 eval.c
--- eval.c	30 Nov 2004 09:33:50 -0000	1.737
+++ eval.c	30 Nov 2004 16:12:23 -0000
@@ -9681,5 +9681,5 @@ rb_trap_eval(cmd, sig, safe)
     THREAD_COPY_STATUS(curr_thread, &save);
     rb_thread_ready(curr_thread);
-    PUSH_TAG(PROT_NONE);
+    PUSH_TAG(PROT_TOP);
     PUSH_ITER(ITER_NOT);
     if ((state = EXEC_TAG()) == 0) {
@@ -11917,4 +11917,8 @@ rb_thread_trap_eval(cmd, sig, safe)
 {
     rb_thread_critical = 0;
+    if (curr_thread == main_thread) {
+	rb_trap_eval(cmd, sig, safe);
+	return;
+    }
     if (!rb_thread_dead(curr_thread)) {
 	if (THREAD_SAVE_CONTEXT(curr_thread)) {
@@ -12261,5 +12265,5 @@ rb_callcc(self)
     rb_thread_t th;
     volatile rb_thread_t th_save;
-    struct tag *tag;
+    struct tag *tag, *top = 0;
     struct RVarmap *vars;
 
@@ -12270,6 +12274,8 @@ rb_callcc(self)
     for (tag=prot_tag; tag; tag=tag->prev) {
 	scope_dup(tag->scope);
+	if (!top && tag->tag == PROT_TOP) top = tag;
     }
     th->thread = curr_thread->thread;
+    th->join = (void *)top;
 
     for (vars = ruby_dyna_vars; vars; vars = vars->next) {
@@ -12309,8 +12315,18 @@ rb_cont_call(argc, argv, cont)
 {
     rb_thread_t th = rb_thread_check(cont);
+    struct tag *tag, *top = 0;
 
     if (th->thread != curr_thread->thread) {
 	rb_raise(rb_eRuntimeError, "continuation called across threads");
     }
+    for (tag=prot_tag; tag; tag=tag->prev) {
+	if (tag->tag == PROT_TOP) {
+	    top = tag;
+	    break;
+	}
+    }
+    if ((void *)th->join != (void *)top) {
+	rb_raise(rb_eRuntimeError, "continuation called across trap");
+    }
     switch (argc) {
       case 0:


-- 
--- 僕の前にBugはない。
--- 僕の後ろにBugはできる。
    中田 伸悦