Re: TIOCGDEV ioctl

[Alexander Viro <viro@math.psu.edu>]

On Fri, 15 Dec 2000, Linus Torvalds wrote:

> Please instead do the same thing /dev/tty does, namely a sane interface
> that shows it as a symlink in /proc (or even in /dev)


There you go... (/proc/tty/console -> /dev/tty<current_VC>; may very well
be dangling, but then you have a current VC even if your /dev consists
of /dev/console and nothing else, so there's nothing to do about that;
doesn't handle TIOCCONS redirects, but IMO that should be a separate
object anyway).
							Cheers,
								Al

diff -urN rc12-pre8/fs/proc/proc_tty.c rc12-pre8-tty/fs/proc/proc_tty.c
--- rc12-pre8/fs/proc/proc_tty.c	Sat Apr 22 02:35:31 2000
+++ rc12-pre8-tty/fs/proc/proc_tty.c	Sat Dec 16 00:14:20 2000
@@ -166,6 +166,26 @@
 	driver->proc_entry = 0;
 }
 
+extern int fg_console;
+static int proc_cons_readlink(struct dentry *dentry, char *buffer, int buflen)
+{
+	char tmp[30];
+	sprintf(tmp, "/dev/tty%d", fg_console);
+	return vfs_readlink(dentry,buffer,buflen,tmp);
+}
+
+static int proc_cons_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+	char tmp[30];
+	sprintf(tmp, "/dev/tty%d", fg_console);
+	return vfs_follow_link(nd,tmp);
+}	
+
+static struct inode_operations proc_cons_operations = {
+	readlink:	proc_cons_readlink,
+	follow_link:	proc_cons_follow_link,
+};
+
 /*
  * Called by proc_root_init() to initialize the /proc/tty subtree
  */
@@ -175,6 +195,9 @@
 		return;
 	proc_tty_ldisc = proc_mkdir("tty/ldisc", 0);
 	proc_tty_driver = proc_mkdir("tty/driver", 0);
+
+	proc_tty_console = create_proc_entry("tty/console", S_IFLNK|0777, NULL);
+	proc_tty_console->proc_iops = &proc_console_ops;
 
 	create_proc_read_entry("tty/ldiscs", 0, 0, tty_ldiscs_read_proc,NULL);
 	create_proc_read_entry("tty/drivers", 0, 0, tty_drivers_read_proc,NULL);

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