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/*
* proc_tty.c -- handles /proc/tty
*
* Copyright 1997, Theodore Ts'o
*/
#include <asm/uaccess.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/tty.h>
#include <asm/bitops.h>
extern struct tty_driver *tty_drivers; /* linked list of tty drivers */
extern struct tty_ldisc ldiscs[];
static int tty_drivers_read_proc(char *page, char **start, off_t off,
int count, int *eof, void *data);
static int tty_ldiscs_read_proc(char *page, char **start, off_t off,
int count, int *eof, void *data);
/*
* The /proc/tty directory inodes...
*/
static struct proc_dir_entry *proc_tty_ldisc, *proc_tty_driver;
/*
* This is the handler for /proc/tty/drivers
*/
static int tty_drivers_read_proc(char *page, char **start, off_t off,
int count, int *eof, void *data)
{
int len = 0;
off_t begin = 0;
struct tty_driver *p;
char range[20], deftype[20];
char *type;
for (p = tty_drivers; p; p = p->next) {
if (p->num > 1)
sprintf(range, "%d-%d", p->minor_start,
p->minor_start + p->num - 1);
else
sprintf(range, "%d", p->minor_start);
switch (p->type) {
case TTY_DRIVER_TYPE_SYSTEM:
if (p->subtype == SYSTEM_TYPE_TTY)
type = "system:/dev/tty";
else if (p->subtype == SYSTEM_TYPE_SYSCONS)
type = "system:console";
else if (p->subtype == SYSTEM_TYPE_CONSOLE)
type = "system:vtmaster";
else
type = "system";
break;
case TTY_DRIVER_TYPE_CONSOLE:
type = "console";
break;
case TTY_DRIVER_TYPE_SERIAL:
if (p->subtype == 2)
type = "serial:callout";
else
type = "serial";
break;
case TTY_DRIVER_TYPE_PTY:
if (p->subtype == PTY_TYPE_MASTER)
type = "pty:master";
else if (p->subtype == PTY_TYPE_SLAVE)
type = "pty:slave";
else
type = "pty";
break;
default:
sprintf(deftype, "type:%d.%d", p->type, p->subtype);
type = deftype;
break;
}
len += sprintf(page+len, "%-20s /dev/%-8s %3d %7s %s\n",
p->driver_name ? p->driver_name : "unknown",
p->name, p->major, range, type);
if (len+begin > off+count)
break;
if (len+begin < off) {
begin += len;
len = 0;
}
}
if (!p)
*eof = 1;
if (off >= len+begin)
return 0;
*start = page + (off-begin);
return ((count < begin+len-off) ? count : begin+len-off);
}
/*
* This is the handler for /proc/tty/ldiscs
*/
static int tty_ldiscs_read_proc(char *page, char **start, off_t off,
int count, int *eof, void *data)
{
int i;
int len = 0;
off_t begin = 0;
for (i=0; i < NR_LDISCS; i++) {
if (!(ldiscs[i].flags & LDISC_FLAG_DEFINED))
continue;
len += sprintf(page+len, "%-10s %2d\n",
ldiscs[i].name ? ldiscs[i].name : "???", i);
if (len+begin > off+count)
break;
if (len+begin < off) {
begin += len;
len = 0;
}
}
if (i >= NR_LDISCS)
*eof = 1;
if (off >= len+begin)
return 0;
*start = page + (off-begin);
return ((count < begin+len-off) ? count : begin+len-off);
}
/*
* 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->read_proc && !driver->write_proc) ||
!driver->driver_name ||
driver->proc_entry)
return;
ent = create_proc_entry(driver->driver_name, 0, proc_tty_driver);
if (!ent)
return;
ent->read_proc = driver->read_proc;
ent->write_proc = driver->write_proc;
ent->data = 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(driver->driver_name, proc_tty_driver);
driver->proc_entry = 0;
}
/*
* Called by proc_root_init() to initialize the /proc/tty subtree
*/
void __init proc_tty_init(void)
{
if (!proc_mkdir("tty", 0))
return;
proc_tty_ldisc = proc_mkdir("tty/ldisc", 0);
/*
* /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, 0);
create_proc_read_entry("tty/ldiscs", 0, 0, tty_ldiscs_read_proc,NULL);
create_proc_read_entry("tty/drivers", 0, 0, tty_drivers_read_proc,NULL);
}
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