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Subject[PATCH 12/22] UML - Fix SIGWINCH relaying
Date
From
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>

Index: linux-2.6.11-mm/arch/um/drivers/line.c
===================================================================
--- linux-2.6.11-mm.orig/arch/um/drivers/line.c 2005-04-30 12:57:43.000000000 -0400
+++ linux-2.6.11-mm/arch/um/drivers/line.c 2005-04-30 13:09:17.000000000 -0400
@@ -462,12 +462,15 @@
return err;
}

+static void unregister_winch(struct tty_struct *tty);
+
void line_close(struct tty_struct *tty, struct file * filp)
{
struct line *line = tty->driver_data;

- /* XXX: I assume this should be called in process context, not with interrupt
- * disabled!*/
+ /* XXX: I assume this should be called in process context, not with
+ * interrupts disabled!
+ */
spin_lock_irq(&line->lock);

/* We ignore the error anyway! */
@@ -478,6 +481,12 @@
line_disable(tty, -1);
tty->driver_data = NULL;
}
+
+ if((line->count == 0) && line->sigio){
+ unregister_winch(tty);
+ line->sigio = 0;
+ }
+
spin_unlock_irq(&line->lock);
}

@@ -729,6 +738,34 @@
up(&winch_handler_sem);
}

+static void unregister_winch(struct tty_struct *tty)
+{
+ struct list_head *ele;
+ struct winch *winch, *found = NULL;
+
+ down(&winch_handler_sem);
+ list_for_each(ele, &winch_handlers){
+ winch = list_entry(ele, struct winch, list);
+ if(winch->tty == tty){
+ found = winch;
+ break;
+ }
+ }
+
+ if(found == NULL)
+ goto out;
+
+ if(winch->pid != -1)
+ os_kill_process(winch->pid, 1);
+
+ free_irq_by_irq_and_dev(WINCH_IRQ, winch);
+ free_irq(WINCH_IRQ, winch);
+ list_del(&winch->list);
+ kfree(winch);
+ out:
+ up(&winch_handler_sem);
+}
+
static void winch_cleanup(void)
{
struct list_head *ele;
Index: linux-2.6.11-mm/arch/um/include/os.h
===================================================================
--- linux-2.6.11-mm.orig/arch/um/include/os.h 2005-04-30 12:56:24.000000000 -0400
+++ linux-2.6.11-mm/arch/um/include/os.h 2005-04-30 13:08:14.000000000 -0400
@@ -160,6 +160,7 @@
extern void os_kill_ptraced_process(int pid, int reap_child);
extern void os_usr1_process(int pid);
extern int os_getpid(void);
+extern int os_getpgrp(void);

extern int os_map_memory(void *virt, int fd, unsigned long long off,
unsigned long len, int r, int w, int x);
Index: linux-2.6.11-mm/arch/um/kernel/irq.c
===================================================================
--- linux-2.6.11-mm.orig/arch/um/kernel/irq.c 2005-04-30 12:56:24.000000000 -0400
+++ linux-2.6.11-mm/arch/um/kernel/irq.c 2005-04-30 13:08:14.000000000 -0400
@@ -163,7 +163,6 @@
irq_desc[i].handler = &SIGIO_irq_type;
enable_irq(i);
}
- init_irq_signals(0);
}

/*
Index: linux-2.6.11-mm/arch/um/kernel/process.c
===================================================================
--- linux-2.6.11-mm.orig/arch/um/kernel/process.c 2005-04-30 12:56:24.000000000 -0400
+++ linux-2.6.11-mm/arch/um/kernel/process.c 2005-04-30 13:08:14.000000000 -0400
@@ -65,8 +65,6 @@
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);
Index: linux-2.6.11-mm/arch/um/kernel/sigio_user.c
===================================================================
--- linux-2.6.11-mm.orig/arch/um/kernel/sigio_user.c 2005-04-30 12:56:24.000000000 -0400
+++ linux-2.6.11-mm/arch/um/kernel/sigio_user.c 2005-04-30 13:08:14.000000000 -0400
@@ -182,6 +182,7 @@
int i, n, respond_fd;
char c;

+ signal(SIGWINCH, SIG_IGN);
fds = &current_poll;
while(1){
n = poll(fds->poll, fds->used, -1);
Index: linux-2.6.11-mm/arch/um/kernel/skas/process.c
===================================================================
--- linux-2.6.11-mm.orig/arch/um/kernel/skas/process.c 2005-04-30 13:08:02.000000000 -0400
+++ linux-2.6.11-mm/arch/um/kernel/skas/process.c 2005-04-30 13:08:14.000000000 -0400
@@ -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 @@
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)
Index: linux-2.6.11-mm/arch/um/kernel/tt/tracer.c
===================================================================
--- linux-2.6.11-mm.orig/arch/um/kernel/tt/tracer.c 2005-04-30 13:08:02.000000000 -0400
+++ linux-2.6.11-mm/arch/um/kernel/tt/tracer.c 2005-04-30 13:08:14.000000000 -0400
@@ -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 @@

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 @@
signal(SIGSEGV, (__sighandler_t) sig_handler);
set_cmdline("(idle thread)");
set_init_pid(os_getpid());
+ init_irq_signals(0);
proc = arg;
return((*proc)(NULL));
}
Index: linux-2.6.11-mm/arch/um/os-Linux/process.c
===================================================================
--- linux-2.6.11-mm.orig/arch/um/os-Linux/process.c 2005-04-30 12:56:24.000000000 -0400
+++ linux-2.6.11-mm/arch/um/os-Linux/process.c 2005-04-30 13:08:14.000000000 -0400
@@ -123,6 +123,11 @@
return(getpid());
}

+int os_getpgrp(void)
+{
+ return getpgrp();
+}
+
int os_map_memory(void *virt, int fd, unsigned long long off, unsigned long len,
int r, int w, int x)
{
-
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