[PATCH] uml: Fix SIGWINCH relaying

This makes SIGWINCH work again, and fixes a couple of SIGWINCH-associated
crashes.  First, the sigio thread disables SIGWINCH because all hell breaks
loose if it ever gets one and tries to call the signal handling code.  Second,
there was a problem with deferencing tty structs after they were freed.  The
SIGWINCH support for a tty wasn't being turned off or freed after the tty went
away.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

5 files changed, 10 insertions, 5 deletions

diff --git a/arch/um/kernel/irq.c b/arch/um/kernel/irq.c
index d71e8f00810f..d44fb5282547 100644
--- a/arch/um/kernel/irq.c
+++ b/arch/um/kernel/irq.c
@@ -163,7 +163,6 @@ void __init init_IRQ(void)
                 irq_desc[i].handler = &SIGIO_irq_type;
                 enable_irq(i);
         }
-        init_irq_signals(0);
 }
 
 /*
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index f76a2692adca..51f8e5a8ac6a 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -65,8 +65,6 @@ void init_new_thread_signals(int altstack)
                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
         set_handler(SIGBUS, (__sighandler_t) sig_handler, flags, 
                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
-        set_handler(SIGWINCH, (__sighandler_t) sig_handler, flags, 
-                    SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
         set_handler(SIGUSR2, (__sighandler_t) sig_handler, 
                     flags, SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
         signal(SIGHUP, SIG_IGN);
diff --git a/arch/um/kernel/sigio_user.c b/arch/um/kernel/sigio_user.c
index 668df13d8c9d..e89218958f38 100644
--- a/arch/um/kernel/sigio_user.c
+++ b/arch/um/kernel/sigio_user.c
@@ -182,6 +182,7 @@ static int write_sigio_thread(void *unused)
         int i, n, respond_fd;
         char c;
 
+        signal(SIGWINCH, SIG_IGN);
         fds = &current_poll;
         while(1){
                 n = poll(fds->poll, fds->used, -1);
diff --git a/arch/um/kernel/skas/process.c b/arch/um/kernel/skas/process.c
index c0b30515dfb6..4dc13bc8cfd8 100644
--- a/arch/um/kernel/skas/process.c
+++ b/arch/um/kernel/skas/process.c
@@ -28,10 +28,11 @@
 #include "chan_user.h"
 #include "signal_user.h"
 #include "registers.h"
+#include "process.h"
 
 int is_skas_winch(int pid, int fd, void *data)
 {
-        if(pid != os_getpid())
+        if(pid != os_getpgrp())
                 return(0);
 
         register_winch_irq(-1, fd, -1, data);
@@ -259,6 +260,10 @@ int start_idle_thread(void *stack, void *switch_buf_ptr, void **fork_buf_ptr)
         sigjmp_buf **switch_buf = switch_buf_ptr;
         int n;
 
+        set_handler(SIGWINCH, (__sighandler_t) sig_handler,
+                    SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGALRM,
+                    SIGVTALRM, -1);
+
         *fork_buf_ptr = &initial_jmpbuf;
         n = sigsetjmp(initial_jmpbuf, 1);
         if(n == 0)
diff --git a/arch/um/kernel/tt/tracer.c b/arch/um/kernel/tt/tracer.c
index f7b1753a025c..d11e7399d7a1 100644
--- a/arch/um/kernel/tt/tracer.c
+++ b/arch/um/kernel/tt/tracer.c
@@ -26,6 +26,7 @@
 #include "kern_util.h"
 #include "chan_user.h"
 #include "ptrace_user.h"
+#include "irq_user.h"
 #include "mode.h"
 #include "tt.h"
 
@@ -33,7 +34,7 @@ static int tracer_winch[2];
 
 int is_tracer_winch(int pid, int fd, void *data)
 {
-        if(pid != tracing_pid)
+        if(pid != os_getpgrp())
                 return(0);
 
         register_winch_irq(tracer_winch[0], fd, -1, data);
@@ -119,6 +120,7 @@ static int signal_tramp(void *arg)
         signal(SIGSEGV, (__sighandler_t) sig_handler);
         set_cmdline("(idle thread)");
         set_init_pid(os_getpid());
+        init_irq_signals(0);
         proc = arg;
         return((*proc)(NULL));
 }