[PATCH, RFC] Standardize shutdown of the system from enviroment control modules

[Christoph Hellwig <hch@lst.de>]

On Tue, Aug 09, 2005 at 11:10:03PM +0200, Christoph Hellwig wrote:
> Currently snsc_event for Altix systems sends SIGPWR to init (and abuses
> tasklist_lock..) while the sbus drivers call execve for /sbin/shutdown
> (which is also ugly, it should at least use call_usermodehelper)
> With normal sysvinit both will end up the same, but I suspect the
> shutdown variant, maybe with a sysctl to chose the exact path to call
> would be cleaner.  What do you guys think about adding a common function
> to do this.  Could you test such a patch for me?

Okay, here's such a patch, I've also switched the SN and the two sbus
drivers over.


Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: linux-2.6/drivers/char/snsc_event.c
===================================================================
--- linux-2.6.orig/drivers/char/snsc_event.c	2005-08-11 16:45:55.000000000 +0200
+++ linux-2.6/drivers/char/snsc_event.c	2005-08-11 19:03:59.000000000 +0200
@@ -195,24 +195,7 @@
 	severity = scdrv_event_severity(code);
 
 	if ((code & EV_CLASS_MASK) == EV_CLASS_PWRD_NOTIFY) {
-		struct task_struct *p;
-
-		/* give a SIGPWR signal to init proc */
-
-		/* first find init's task */
-		read_lock(&tasklist_lock);
-		for_each_process(p) {
-			if (p->pid == 1)
-				break;
-		}
-		if (p) { /* we found init's task */
-			printk(KERN_EMERG "Power off indication received. Initiating power fail sequence...\n");
-			force_sig(SIGPWR, p);
-		} else { /* failed to find init's task - just give message(s) */
-			printk(KERN_WARNING "Failed to find init proc to handle power off!\n");
-			printk("%s|$(0x%x)%s\n", severity, esp_code, desc);
-		}
-		read_unlock(&tasklist_lock);
+		envctrl_do_shutdown();
 	} else {
 		/* print to system log */
 		printk("%s|$(0x%x)%s\n", severity, esp_code, desc);
Index: linux-2.6/drivers/sbus/char/bbc_envctrl.c
===================================================================
--- linux-2.6.orig/drivers/sbus/char/bbc_envctrl.c	2005-08-11 16:45:59.000000000 +0200
+++ linux-2.6/drivers/sbus/char/bbc_envctrl.c	2005-08-11 19:01:44.000000000 +0200
@@ -4,13 +4,12 @@
  * Copyright (C) 2001 David S. Miller (davem@redhat.com)
  */
 
-#define __KERNEL_SYSCALLS__
-
 #include <linux/kernel.h>
 #include <linux/kthread.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/delay.h>
+#include <linux/envctrl.h>
 #include <asm/oplib.h>
 #include <asm/ebus.h>
 static int errno;
@@ -176,8 +175,6 @@
 static void do_envctrl_shutdown(struct bbc_cpu_temperature *tp)
 {
 	static int shutting_down = 0;
-	static char *envp[] = { "HOME=/", "TERM=linux", "PATH=/sbin:/usr/sbin:/bin:/usr/bin", NULL };
-	char *argv[] = { "/sbin/shutdown", "-h", "now", NULL };
 	char *type = "???";
 	s8 val = -1;
 
@@ -201,8 +198,8 @@
 	printk(KERN_CRIT "kenvctrld: Shutting down the system now.\n");
 
 	shutting_down = 1;
-	if (execve("/sbin/shutdown", argv, envp) < 0)
-		printk(KERN_CRIT "envctrl: shutdown execution failed\n");
+
+	envctrl_do_shutdown();
 }
 
 #define WARN_INTERVAL	(30 * HZ)
Index: linux-2.6/drivers/sbus/char/envctrl.c
===================================================================
--- linux-2.6.orig/drivers/sbus/char/envctrl.c	2005-08-11 16:45:59.000000000 +0200
+++ linux-2.6/drivers/sbus/char/envctrl.c	2005-08-11 19:01:57.000000000 +0200
@@ -19,8 +19,6 @@
  *              Daniele Bellucci <bellucda@tiscali.it>
  */
 
-#define __KERNEL_SYSCALLS__
-
 #include <linux/config.h>
 #include <linux/module.h>
 #include <linux/sched.h>
@@ -33,6 +31,7 @@
 #include <linux/mm.h>
 #include <linux/slab.h>
 #include <linux/kernel.h>
+#include <linux/envctrl.h>
 
 #include <asm/ebus.h>
 #include <asm/uaccess.h>
@@ -975,25 +974,6 @@
 	return NULL;
 }
 
-static void envctrl_do_shutdown(void)
-{
-	static int inprog = 0;
-	static char *envp[] = {	
-		"HOME=/", "TERM=linux", "PATH=/sbin:/usr/sbin:/bin:/usr/bin", NULL };
-	char *argv[] = { 
-		"/sbin/shutdown", "-h", "now", NULL };	
-
-	if (inprog != 0)
-		return;
-
-	inprog = 1;
-	printk(KERN_CRIT "kenvctrld: WARNING: Shutting down the system now.\n");
-	if (0 > execve("/sbin/shutdown", argv, envp)) {
-		printk(KERN_CRIT "kenvctrld: WARNING: system shutdown failed!\n"); 
-		inprog = 0;  /* unlikely to succeed, but we could try again */
-	}
-}
-
 static struct task_struct *kenvctrld_task;
 
 static int kenvctrld(void *__unused)
Index: linux-2.6/include/linux/envctrl.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6/include/linux/envctrl.h	2005-08-11 18:58:41.000000000 +0200
@@ -0,0 +1,6 @@
+#ifndef _LINUX_ENVCTRL_H
+#define _LINUX_ENVCTRL_H
+
+extern int envctrl_do_shutdown(void);
+
+#endif /* _LINUX_ENVCTRL_H */
Index: linux-2.6/kernel/Makefile
===================================================================
--- linux-2.6.orig/kernel/Makefile	2005-08-11 16:46:07.000000000 +0200
+++ linux-2.6/kernel/Makefile	2005-08-11 18:57:57.000000000 +0200
@@ -7,7 +7,7 @@
 	    sysctl.o capability.o ptrace.o timer.o user.o \
 	    signal.o sys.o kmod.o workqueue.o pid.o \
 	    rcupdate.o intermodule.o extable.o params.o posix-timers.o \
-	    kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o
+	    kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o envctrl.o
 
 obj-$(CONFIG_FUTEX) += futex.o
 obj-$(CONFIG_GENERIC_ISA_DMA) += dma.o
Index: linux-2.6/kernel/envctrl.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6/kernel/envctrl.c	2005-08-11 19:04:19.000000000 +0200
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2001 David S. Miller.
+ * Copyright (C) 2005 Christoph Hellwig.
+ *	Released under GPL v2.
+ *
+ * Common code to shutdown the system when overheating.
+ */
+
+#include <linux/envctrl.h>
+#include <linux/kernel.h>
+#include <linux/kmod.h>
+
+static char *envp[] = {
+	"HOME=/", "TERM=linux", "PATH=/sbin:/usr/sbin:/bin:/usr/bin", NULL
+};
+
+static char *argv[] = {
+	"/sbin/shutdown", "-h", "now", NULL
+};
+
+/*
+ * envctrl_do_shutdown  -  shut the system down when overheating
+ *
+ * Common routine to be called from all enviromental monitoring
+ * drivers when a fatal overheating is detected.
+ *
+ * Returns 0 if /sbin/shutdown has been called sucessfully, 1 if
+ * this routine has been called already but the kernel is still
+ * running or a negative error value if executing the shutdown
+ * command failed.
+ */
+int envctrl_do_shutdown(void)
+{
+	static int shutting_down = 0;
+	int error;
+
+	if (shutting_down)
+		return 1;
+	shutting_down = 1;
+
+	printk(KERN_CRIT "envctrl: WARNING: Shutting down the system now.\n");
+	error = call_usermodehelper("/sbin/shutdown", argv, envp, 0);
+	if (error)
+		printk(KERN_CRIT "envctrl: WARNING: system shutdown failed!\n");
+	return error;
+}