From: Randy Dunlap <rdunlap@xenotime.net>

Add /proc/consoles to list all registered consoles by name,
along with their I/O capabilities and flags.

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
---
 kernel/printk.c |   64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 64 insertions(+)

--- linux-2616-rc6.orig/kernel/printk.c
+++ linux-2616-rc6/kernel/printk.c
@@ -27,8 +27,10 @@
 #include <linux/interrupt.h>			/* For in_interrupt() */
 #include <linux/config.h>
 #include <linux/delay.h>
+#include <linux/proc_fs.h>
 #include <linux/smp.h>
 #include <linux/security.h>
+#include <linux/seq_file.h>
 #include <linux/bootmem.h>
 #include <linux/syscalls.h>
 
@@ -1049,3 +1051,65 @@ int printk_ratelimit(void)
 				printk_ratelimit_burst);
 }
 EXPORT_SYMBOL(printk_ratelimit);
+
+#ifdef CONFIG_PROC_FS
+static int con_show(struct seq_file *m, void *v)
+{
+	struct console *con;
+
+	acquire_console_sem();
+	for (con = console_drivers; con; con = con->next)
+		printk("%d: %-8s %c:%c:%c flags:%s%s%s%s%s\n",
+			con->index, con->name,
+			con->read ? 'R' : 'x',
+			con->write ? 'W' : 'x',
+			con->unblank ? 'U' : 'x',
+			!con->flags ? " none" : "",
+			con->flags & CON_PRINTBUFFER ? " print" : "",
+			con->flags & CON_CONSDEV ? " consoledev" : "",
+			con->flags & CON_ENABLED ? " enabled" : "",
+			con->flags & CON_BOOT ? " boot" : "");
+
+	release_console_sem();
+	return 0;
+}
+
+static int consoles_open(struct inode *inode, struct file *file)
+{
+	struct seq_file *m;
+	int res;
+	char *buf;
+	unsigned int size = PAGE_SIZE;
+
+	buf = kmalloc(size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	res = single_open(file, con_show, NULL);
+	if (!res) {
+		m = file->private_data;
+		m->buf = buf;
+		m->size = size;
+	} else
+		kfree(buf);
+	return res;
+}
+
+static struct file_operations proc_consoles_operations = {
+	.open		= consoles_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static int __init consoles_init(void)
+{
+	struct proc_dir_entry *entry;
+
+	entry = create_proc_entry("consoles", 0, NULL);
+	if (entry)
+		entry->proc_fops = &proc_consoles_operations;
+	return 0;
+}
+__initcall(consoles_init);
+#endif /* CONFIG_PROC_FS */