178 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * proc_tty.c -- handles /proc/tty4 *5 * Copyright 1997, Theodore Ts'o6 */7#include <linux/module.h>8#include <linux/init.h>9#include <linux/errno.h>10#include <linux/time.h>11#include <linux/proc_fs.h>12#include <linux/stat.h>13#include <linux/tty.h>14#include <linux/seq_file.h>15#include <linux/bitops.h>16#include "internal.h"17 18/*19 * The /proc/tty directory inodes...20 */21static struct proc_dir_entry *proc_tty_driver;22 23/*24 * This is the handler for /proc/tty/drivers25 */26static void show_tty_range(struct seq_file *m, struct tty_driver *p,27 dev_t from, int num)28{29 seq_printf(m, "%-20s ", p->driver_name ? p->driver_name : "unknown");30 seq_printf(m, "/dev/%-8s ", p->name);31 if (p->num > 1) {32 seq_printf(m, "%3d %d-%d ", MAJOR(from), MINOR(from),33 MINOR(from) + num - 1);34 } else {35 seq_printf(m, "%3d %7d ", MAJOR(from), MINOR(from));36 }37 switch (p->type) {38 case TTY_DRIVER_TYPE_SYSTEM:39 seq_puts(m, "system");40 if (p->subtype == SYSTEM_TYPE_TTY)41 seq_puts(m, ":/dev/tty");42 else if (p->subtype == SYSTEM_TYPE_SYSCONS)43 seq_puts(m, ":console");44 else if (p->subtype == SYSTEM_TYPE_CONSOLE)45 seq_puts(m, ":vtmaster");46 break;47 case TTY_DRIVER_TYPE_CONSOLE:48 seq_puts(m, "console");49 break;50 case TTY_DRIVER_TYPE_SERIAL:51 seq_puts(m, "serial");52 break;53 case TTY_DRIVER_TYPE_PTY:54 if (p->subtype == PTY_TYPE_MASTER)55 seq_puts(m, "pty:master");56 else if (p->subtype == PTY_TYPE_SLAVE)57 seq_puts(m, "pty:slave");58 else59 seq_puts(m, "pty");60 break;61 default:62 seq_printf(m, "type:%d.%d", p->type, p->subtype);63 }64 seq_putc(m, '\n');65}66 67static int show_tty_driver(struct seq_file *m, void *v)68{69 struct tty_driver *p = list_entry(v, struct tty_driver, tty_drivers);70 dev_t from = MKDEV(p->major, p->minor_start);71 dev_t to = from + p->num;72 73 if (&p->tty_drivers == tty_drivers.next) {74 /* pseudo-drivers first */75 seq_printf(m, "%-20s /dev/%-8s ", "/dev/tty", "tty");76 seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 0);77 seq_puts(m, "system:/dev/tty\n");78 seq_printf(m, "%-20s /dev/%-8s ", "/dev/console", "console");79 seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 1);80 seq_puts(m, "system:console\n");81#ifdef CONFIG_UNIX98_PTYS82 seq_printf(m, "%-20s /dev/%-8s ", "/dev/ptmx", "ptmx");83 seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 2);84 seq_puts(m, "system\n");85#endif86#ifdef CONFIG_VT87 seq_printf(m, "%-20s /dev/%-8s ", "/dev/vc/0", "vc/0");88 seq_printf(m, "%3d %7d ", TTY_MAJOR, 0);89 seq_puts(m, "system:vtmaster\n");90#endif91 }92 93 while (MAJOR(from) < MAJOR(to)) {94 dev_t next = MKDEV(MAJOR(from)+1, 0);95 show_tty_range(m, p, from, next - from);96 from = next;97 }98 if (from != to)99 show_tty_range(m, p, from, to - from);100 return 0;101}102 103/* iterator */104static void *t_start(struct seq_file *m, loff_t *pos)105{106 mutex_lock(&tty_mutex);107 return seq_list_start(&tty_drivers, *pos);108}109 110static void *t_next(struct seq_file *m, void *v, loff_t *pos)111{112 return seq_list_next(v, &tty_drivers, pos);113}114 115static HWJS_SUSPENDS void t_stop(struct seq_file *m, void *v)116{117 mutex_unlock(&tty_mutex);118}119 120static const struct seq_operations tty_drivers_op = {121 .start = t_start,122 .next = t_next,123 .stop = t_stop,124 .show = show_tty_driver125};126 127/*128 * This function is called by tty_register_driver() to handle129 * registering the driver's /proc handler into /proc/tty/driver/<foo>130 */131void proc_tty_register_driver(struct tty_driver *driver)132{133 struct proc_dir_entry *ent;134 135 if (!driver->driver_name || driver->proc_entry ||136 !driver->ops->proc_show)137 return;138 139 ent = proc_create_single_data(driver->driver_name, 0, proc_tty_driver,140 driver->ops->proc_show, driver);141 driver->proc_entry = ent;142}143 144/*145 * This function is called by tty_unregister_driver()146 */147void proc_tty_unregister_driver(struct tty_driver *driver)148{149 struct proc_dir_entry *ent;150 151 ent = driver->proc_entry;152 if (!ent)153 return;154 155 remove_proc_entry(ent->name, proc_tty_driver);156 157 driver->proc_entry = NULL;158}159 160/*161 * Called by proc_root_init() to initialize the /proc/tty subtree162 */163void __init proc_tty_init(void)164{165 if (!proc_mkdir("tty", NULL))166 return;167 proc_mkdir("tty/ldisc", NULL); /* Preserved: it's userspace visible */168 /*169 * /proc/tty/driver/serial reveals the exact character counts for170 * serial links which is just too easy to abuse for inferring171 * password lengths and inter-keystroke timings during password172 * entry.173 */174 proc_tty_driver = proc_mkdir_mode("tty/driver", S_IRUSR|S_IXUSR, NULL);175 proc_create_seq("tty/ldiscs", 0, NULL, &tty_ldiscs_seq_ops);176 proc_create_seq("tty/drivers", 0, NULL, &tty_drivers_op);177}178