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-rw-r--r--fs/proc/proc_tty.c179
1 files changed, 179 insertions, 0 deletions
diff --git a/fs/proc/proc_tty.c b/fs/proc/proc_tty.c
new file mode 100644
index 000000000..c69ff191e
--- /dev/null
+++ b/fs/proc/proc_tty.c
@@ -0,0 +1,179 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * proc_tty.c -- handles /proc/tty
+ *
+ * Copyright 1997, Theodore Ts'o
+ */
+
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/time.h>
+#include <linux/proc_fs.h>
+#include <linux/stat.h>
+#include <linux/tty.h>
+#include <linux/seq_file.h>
+#include <linux/bitops.h>
+#include "internal.h"
+
+/*
+ * The /proc/tty directory inodes...
+ */
+static struct proc_dir_entry *proc_tty_driver;
+
+/*
+ * This is the handler for /proc/tty/drivers
+ */
+static void show_tty_range(struct seq_file *m, struct tty_driver *p,
+ dev_t from, int num)
+{
+ seq_printf(m, "%-20s ", p->driver_name ? p->driver_name : "unknown");
+ seq_printf(m, "/dev/%-8s ", p->name);
+ if (p->num > 1) {
+ seq_printf(m, "%3d %d-%d ", MAJOR(from), MINOR(from),
+ MINOR(from) + num - 1);
+ } else {
+ seq_printf(m, "%3d %7d ", MAJOR(from), MINOR(from));
+ }
+ switch (p->type) {
+ case TTY_DRIVER_TYPE_SYSTEM:
+ seq_puts(m, "system");
+ if (p->subtype == SYSTEM_TYPE_TTY)
+ seq_puts(m, ":/dev/tty");
+ else if (p->subtype == SYSTEM_TYPE_SYSCONS)
+ seq_puts(m, ":console");
+ else if (p->subtype == SYSTEM_TYPE_CONSOLE)
+ seq_puts(m, ":vtmaster");
+ break;
+ case TTY_DRIVER_TYPE_CONSOLE:
+ seq_puts(m, "console");
+ break;
+ case TTY_DRIVER_TYPE_SERIAL:
+ seq_puts(m, "serial");
+ break;
+ case TTY_DRIVER_TYPE_PTY:
+ if (p->subtype == PTY_TYPE_MASTER)
+ seq_puts(m, "pty:master");
+ else if (p->subtype == PTY_TYPE_SLAVE)
+ seq_puts(m, "pty:slave");
+ else
+ seq_puts(m, "pty");
+ break;
+ default:
+ seq_printf(m, "type:%d.%d", p->type, p->subtype);
+ }
+ seq_putc(m, '\n');
+}
+
+static int show_tty_driver(struct seq_file *m, void *v)
+{
+ struct tty_driver *p = list_entry(v, struct tty_driver, tty_drivers);
+ dev_t from = MKDEV(p->major, p->minor_start);
+ dev_t to = from + p->num;
+
+ if (&p->tty_drivers == tty_drivers.next) {
+ /* pseudo-drivers first */
+ seq_printf(m, "%-20s /dev/%-8s ", "/dev/tty", "tty");
+ seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 0);
+ seq_puts(m, "system:/dev/tty\n");
+ seq_printf(m, "%-20s /dev/%-8s ", "/dev/console", "console");
+ seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 1);
+ seq_puts(m, "system:console\n");
+#ifdef CONFIG_UNIX98_PTYS
+ seq_printf(m, "%-20s /dev/%-8s ", "/dev/ptmx", "ptmx");
+ seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 2);
+ seq_puts(m, "system\n");
+#endif
+#ifdef CONFIG_VT
+ seq_printf(m, "%-20s /dev/%-8s ", "/dev/vc/0", "vc/0");
+ seq_printf(m, "%3d %7d ", TTY_MAJOR, 0);
+ seq_puts(m, "system:vtmaster\n");
+#endif
+ }
+
+ while (MAJOR(from) < MAJOR(to)) {
+ dev_t next = MKDEV(MAJOR(from)+1, 0);
+ show_tty_range(m, p, from, next - from);
+ from = next;
+ }
+ if (from != to)
+ show_tty_range(m, p, from, to - from);
+ return 0;
+}
+
+/* iterator */
+static void *t_start(struct seq_file *m, loff_t *pos)
+{
+ mutex_lock(&tty_mutex);
+ return seq_list_start(&tty_drivers, *pos);
+}
+
+static void *t_next(struct seq_file *m, void *v, loff_t *pos)
+{
+ return seq_list_next(v, &tty_drivers, pos);
+}
+
+static void t_stop(struct seq_file *m, void *v)
+{
+ mutex_unlock(&tty_mutex);
+}
+
+static const struct seq_operations tty_drivers_op = {
+ .start = t_start,
+ .next = t_next,
+ .stop = t_stop,
+ .show = show_tty_driver
+};
+
+/*
+ * This function is called by tty_register_driver() to handle
+ * registering the driver's /proc handler into /proc/tty/driver/<foo>
+ */
+void proc_tty_register_driver(struct tty_driver *driver)
+{
+ struct proc_dir_entry *ent;
+
+ if (!driver->driver_name || driver->proc_entry ||
+ !driver->ops->proc_show)
+ return;
+
+ ent = proc_create_single_data(driver->driver_name, 0, proc_tty_driver,
+ driver->ops->proc_show, driver);
+ driver->proc_entry = ent;
+}
+
+/*
+ * This function is called by tty_unregister_driver()
+ */
+void proc_tty_unregister_driver(struct tty_driver *driver)
+{
+ struct proc_dir_entry *ent;
+
+ ent = driver->proc_entry;
+ if (!ent)
+ return;
+
+ remove_proc_entry(ent->name, proc_tty_driver);
+
+ driver->proc_entry = NULL;
+}
+
+/*
+ * Called by proc_root_init() to initialize the /proc/tty subtree
+ */
+void __init proc_tty_init(void)
+{
+ if (!proc_mkdir("tty", NULL))
+ return;
+ proc_mkdir("tty/ldisc", NULL); /* Preserved: it's userspace visible */
+ /*
+ * /proc/tty/driver/serial reveals the exact character counts for
+ * serial links which is just too easy to abuse for inferring
+ * password lengths and inter-keystroke timings during password
+ * entry.
+ */
+ proc_tty_driver = proc_mkdir_mode("tty/driver", S_IRUSR|S_IXUSR, NULL);
+ proc_create_seq("tty/ldiscs", 0, NULL, &tty_ldiscs_seq_ops);
+ proc_create_seq("tty/drivers", 0, NULL, &tty_drivers_op);
+}