Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * proc_tty.c -- handles /proc/tty
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  * Copyright 1997, Theodore Ts'o
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8) #include <linux/uaccess.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) #include <linux/init.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) #include <linux/errno.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) #include <linux/time.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) #include <linux/proc_fs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) #include <linux/stat.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) #include <linux/tty.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) #include <linux/seq_file.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) #include <linux/bitops.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) #include "internal.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21)  * The /proc/tty directory inodes...
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) static struct proc_dir_entry *proc_tty_driver;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26)  * This is the handler for /proc/tty/drivers
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) static void show_tty_range(struct seq_file *m, struct tty_driver *p,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) 	dev_t from, int num)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) 	seq_printf(m, "%-20s ", p->driver_name ? p->driver_name : "unknown");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) 	seq_printf(m, "/dev/%-8s ", p->name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) 	if (p->num > 1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) 		seq_printf(m, "%3d %d-%d ", MAJOR(from), MINOR(from),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) 			MINOR(from) + num - 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) 	} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) 		seq_printf(m, "%3d %7d ", MAJOR(from), MINOR(from));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) 	switch (p->type) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) 	case TTY_DRIVER_TYPE_SYSTEM:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) 		seq_puts(m, "system");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 		if (p->subtype == SYSTEM_TYPE_TTY)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) 			seq_puts(m, ":/dev/tty");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 		else if (p->subtype == SYSTEM_TYPE_SYSCONS)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 			seq_puts(m, ":console");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 		else if (p->subtype == SYSTEM_TYPE_CONSOLE)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 			seq_puts(m, ":vtmaster");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 	case TTY_DRIVER_TYPE_CONSOLE:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 		seq_puts(m, "console");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 	case TTY_DRIVER_TYPE_SERIAL:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 		seq_puts(m, "serial");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 	case TTY_DRIVER_TYPE_PTY:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 		if (p->subtype == PTY_TYPE_MASTER)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 			seq_puts(m, "pty:master");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 		else if (p->subtype == PTY_TYPE_SLAVE)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 			seq_puts(m, "pty:slave");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 		else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 			seq_puts(m, "pty");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 	default:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 		seq_printf(m, "type:%d.%d", p->type, p->subtype);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 	seq_putc(m, '\n');
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) static int show_tty_driver(struct seq_file *m, void *v)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 	struct tty_driver *p = list_entry(v, struct tty_driver, tty_drivers);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 	dev_t from = MKDEV(p->major, p->minor_start);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 	dev_t to = from + p->num;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 	if (&p->tty_drivers == tty_drivers.next) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 		/* pseudo-drivers first */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 		seq_printf(m, "%-20s /dev/%-8s ", "/dev/tty", "tty");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 		seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 		seq_puts(m, "system:/dev/tty\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 		seq_printf(m, "%-20s /dev/%-8s ", "/dev/console", "console");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 		seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 		seq_puts(m, "system:console\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) #ifdef CONFIG_UNIX98_PTYS
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 		seq_printf(m, "%-20s /dev/%-8s ", "/dev/ptmx", "ptmx");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 		seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 2);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 		seq_puts(m, "system\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) #ifdef CONFIG_VT
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 		seq_printf(m, "%-20s /dev/%-8s ", "/dev/vc/0", "vc/0");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 		seq_printf(m, "%3d %7d ", TTY_MAJOR, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 		seq_puts(m, "system:vtmaster\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 	while (MAJOR(from) < MAJOR(to)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 		dev_t next = MKDEV(MAJOR(from)+1, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 		show_tty_range(m, p, from, next - from);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 		from = next;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 	if (from != to)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 		show_tty_range(m, p, from, to - from);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) /* iterator */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) static void *t_start(struct seq_file *m, loff_t *pos)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 	mutex_lock(&tty_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 	return seq_list_start(&tty_drivers, *pos);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) static void *t_next(struct seq_file *m, void *v, loff_t *pos)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 	return seq_list_next(v, &tty_drivers, pos);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) static void t_stop(struct seq_file *m, void *v)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 	mutex_unlock(&tty_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) static const struct seq_operations tty_drivers_op = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 	.start	= t_start,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 	.next	= t_next,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 	.stop	= t_stop,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 	.show	= show_tty_driver
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130)  * This function is called by tty_register_driver() to handle
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131)  * registering the driver's /proc handler into /proc/tty/driver/<foo>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) void proc_tty_register_driver(struct tty_driver *driver)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 	struct proc_dir_entry *ent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 		
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 	if (!driver->driver_name || driver->proc_entry ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 	    !driver->ops->proc_show)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 	ent = proc_create_single_data(driver->driver_name, 0, proc_tty_driver,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 			       driver->ops->proc_show, driver);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 	driver->proc_entry = ent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147)  * This function is called by tty_unregister_driver()
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) void proc_tty_unregister_driver(struct tty_driver *driver)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 	struct proc_dir_entry *ent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 	ent = driver->proc_entry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 	if (!ent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 		
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 	remove_proc_entry(ent->name, proc_tty_driver);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 	
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 	driver->proc_entry = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163)  * Called by proc_root_init() to initialize the /proc/tty subtree
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) void __init proc_tty_init(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 	if (!proc_mkdir("tty", NULL))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 	proc_mkdir("tty/ldisc", NULL);	/* Preserved: it's userspace visible */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 	 * /proc/tty/driver/serial reveals the exact character counts for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 	 * serial links which is just too easy to abuse for inferring
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 	 * password lengths and inter-keystroke timings during password
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 	 * entry.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 	proc_tty_driver = proc_mkdir_mode("tty/driver", S_IRUSR|S_IXUSR, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 	proc_create_seq("tty/ldiscs", 0, NULL, &tty_ldiscs_seq_ops);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 	proc_create_seq("tty/drivers", 0, NULL, &tty_drivers_op);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) }