[PATCH v3 1/2] tty: Move sysctl setup into "core" tty logic

From: Kees Cook
Date: Sat Oct 22 2022 - 14:30:37 EST


In preparation for adding another sysctl to the tty subsystem, move the
tty setup code into the "core" tty code, which contains tty_init() itself.

Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Jiri Slaby <jirislaby@xxxxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
drivers/tty/tty.h | 2 +-
drivers/tty/tty_io.c | 34 ++++++++++++++++++++++++++++++++--
drivers/tty/tty_ldisc.c | 38 +-------------------------------------
3 files changed, 34 insertions(+), 40 deletions(-)

diff --git a/drivers/tty/tty.h b/drivers/tty/tty.h
index 1c08c9b67b16..f45cd683c02e 100644
--- a/drivers/tty/tty.h
+++ b/drivers/tty/tty.h
@@ -93,7 +93,7 @@ void tty_ldisc_release(struct tty_struct *tty);
int __must_check tty_ldisc_init(struct tty_struct *tty);
void tty_ldisc_deinit(struct tty_struct *tty);

-void tty_sysctl_init(void);
+extern int tty_ldisc_autoload;

/* tty_audit.c */
#ifdef CONFIG_AUDIT
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index de06c3c2ff70..fe77a3d41326 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -3572,13 +3572,44 @@ void console_sysfs_notify(void)
sysfs_notify(&consdev->kobj, NULL, "active");
}

+static struct ctl_table tty_table[] = {
+ {
+ .procname = "ldisc_autoload",
+ .data = &tty_ldisc_autoload,
+ .maxlen = sizeof(tty_ldisc_autoload),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = SYSCTL_ONE,
+ },
+ { }
+};
+
+static struct ctl_table tty_dir_table[] = {
+ {
+ .procname = "tty",
+ .mode = 0555,
+ .child = tty_table,
+ },
+ { }
+};
+
+static struct ctl_table tty_root_table[] = {
+ {
+ .procname = "dev",
+ .mode = 0555,
+ .child = tty_dir_table,
+ },
+ { }
+};
+
/*
* Ok, now we can initialize the rest of the tty devices and can count
* on memory allocations, interrupts etc..
*/
int __init tty_init(void)
{
- tty_sysctl_init();
+ register_sysctl_table(tty_root_table);
cdev_init(&tty_cdev, &tty_fops);
if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
@@ -3600,4 +3631,3 @@ int __init tty_init(void)
#endif
return 0;
}
-
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index 776d8a62f77c..e758f44729e7 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -117,7 +117,7 @@ static void put_ldops(struct tty_ldisc_ops *ldops)
raw_spin_unlock_irqrestore(&tty_ldiscs_lock, flags);
}

-static int tty_ldisc_autoload = IS_BUILTIN(CONFIG_LDISC_AUTOLOAD);
+int tty_ldisc_autoload = IS_BUILTIN(CONFIG_LDISC_AUTOLOAD);

/**
* tty_ldisc_get - take a reference to an ldisc
@@ -817,39 +817,3 @@ void tty_ldisc_deinit(struct tty_struct *tty)
tty_ldisc_put(tty->ldisc);
tty->ldisc = NULL;
}
-
-static struct ctl_table tty_table[] = {
- {
- .procname = "ldisc_autoload",
- .data = &tty_ldisc_autoload,
- .maxlen = sizeof(tty_ldisc_autoload),
- .mode = 0644,
- .proc_handler = proc_dointvec,
- .extra1 = SYSCTL_ZERO,
- .extra2 = SYSCTL_ONE,
- },
- { }
-};
-
-static struct ctl_table tty_dir_table[] = {
- {
- .procname = "tty",
- .mode = 0555,
- .child = tty_table,
- },
- { }
-};
-
-static struct ctl_table tty_root_table[] = {
- {
- .procname = "dev",
- .mode = 0555,
- .child = tty_dir_table,
- },
- { }
-};
-
-void tty_sysctl_init(void)
-{
- register_sysctl_table(tty_root_table);
-}
--
2.34.1