X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=kernel%2Fprintk.c;h=9b1f825bc570877355bd7a577cf2182cd30794e1;hb=9bf4aaab3e101692164d49b7ca357651eb691cb6;hp=3b74688184a8d4c7d423a730baeef2804e892937;hpb=5273a3df6485dc2ad6aa7ddd441b9a21970f003b;p=linux-2.6.git

diff --git a/kernel/printk.c b/kernel/printk.c
index 3b7468818..9b1f825bc 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -30,6 +30,7 @@
 #include <linux/smp.h>
 #include <linux/security.h>
 #include <linux/bootmem.h>
+#include <linux/vs_base.h>
 
 #include <asm/uaccess.h>
 
@@ -247,7 +248,10 @@ int do_syslog(int type, char __user * buf, int len)
 	unsigned long i, j, limit, count;
 	int do_clear = 0;
 	char c;
-	int error = 0;
+	int error = -EPERM;
+
+	if (!vx_check(0, VX_ADMIN|VX_WATCH))
+		return error;
 
 	error = security_syslog(type);
 	if (error)
@@ -471,6 +475,27 @@ static void emit_log_char(char c)
 		logged_chars++;
 }
 
+/*
+ * Zap console related locks when oopsing. Only zap at most once
+ * every 10 seconds, to leave time for slow consoles to print a
+ * full oops.
+ */
+static void zap_locks(void)
+{
+	static unsigned long oops_timestamp;
+
+	if (time_after_eq(jiffies, oops_timestamp) &&
+			!time_after(jiffies, oops_timestamp + 30*HZ))
+		return;
+
+	oops_timestamp = jiffies;
+
+	/* If a crash is occurring, make sure we can't deadlock */
+	spin_lock_init(&logbuf_lock);
+	/* And make sure that we print immediately */
+	init_MUTEX(&console_sem);
+}
+
 /*
  * This is printk.  It can be called from any context.  We want it to work.
  * 
@@ -493,12 +518,8 @@ asmlinkage int printk(const char *fmt, ...)
 	static char printk_buf[1024];
 	static int log_level_unknown = 1;
 
-	if (oops_in_progress) {
-		/* If a crash is occurring, make sure we can't deadlock */
-		spin_lock_init(&logbuf_lock);
-		/* And make sure that we print immediately */
-		init_MUTEX(&console_sem);
-	}
+	if (unlikely(oops_in_progress))
+		zap_locks();
 
 	/* This stops the holder of console_sem just where we want him */
 	spin_lock_irqsave(&logbuf_lock, flags);
@@ -666,6 +687,47 @@ void console_unblank(void)
 }
 EXPORT_SYMBOL(console_unblank);
 
+/*
+ * Return the console tty driver structure and its associated index
+ */
+struct tty_driver *console_device(int *index)
+{
+	struct console *c;
+	struct tty_driver *driver = NULL;
+
+	acquire_console_sem();
+	for (c = console_drivers; c != NULL; c = c->next) {
+		if (!c->device)
+			continue;
+		driver = c->device(c, index);
+		if (driver)
+			break;
+	}
+	release_console_sem();
+	return driver;
+}
+
+/*
+ * Prevent further output on the passed console device so that (for example)
+ * serial drivers can disable console output before suspending a port, and can
+ * re-enable output afterwards.
+ */
+void console_stop(struct console *console)
+{
+	acquire_console_sem();
+	console->flags &= ~CON_ENABLED;
+	release_console_sem();
+}
+EXPORT_SYMBOL(console_stop);
+
+void console_start(struct console *console)
+{
+	acquire_console_sem();
+	console->flags |= CON_ENABLED;
+	release_console_sem();
+}
+EXPORT_SYMBOL(console_start);
+
 /*
  * The console driver calls this routine during kernel initialization
  * to register the console printing procedure with printk() and to