// 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); }