![Alexey Dobriyan](/assets/img/avatar_default.png)
Additions and removal from tty_drivers list were just done as well as iterating on it for /proc/tty/drivers generation. testing: modprobe/rmmod loop of simple module which does nothing but tty_register_driver() vs cat /proc/tty/drivers loop BUG: unable to handle kernel paging request at virtual address 6b6b6b6b printing eip: c01cefa7 *pde = 00000000 Oops: 0000 [#1] PREEMPT last sysfs file: devices/pci0000:00/0000:00:1d.7/usb5/5-0:1.0/bInterfaceProtocol Modules linked in: ohci_hcd af_packet e1000 ehci_hcd uhci_hcd usbcore xfs CPU: 0 EIP: 0060:[<c01cefa7>] Not tainted VLI EFLAGS: 00010297 (2.6.21-rc4-mm1 #4) EIP is at vsnprintf+0x3a4/0x5fc eax: 6b6b6b6b ebx: f6cb50f2 ecx: 6b6b6b6b edx: fffffffe esi: c0354700 edi: f6cb6000 ebp: 6b6b6b6b esp: f31f5e68 ds: 007b es: 007b fs: 00d8 gs: 0033 ss: 0068 Process cat (pid: 31864, ti=f31f4000 task=c1998030 task.ti=f31f4000) Stack: 00000000 c0103f20 c013003a c0103f20 00000000 f6cb50da 0000000a 00000f0e f6cb50f2 00000010 00000014 ffffffff ffffffff 00000007 c0354753 f6cb50f2 f73e39dc f73e39dc 00000001 c0175416 f31f5ed8 f31f5ed4 0ee00000 f32090bc Call Trace: [<c0103f20>] restore_nocheck+0x12/0x15 [<c013003a>] mark_held_locks+0x6d/0x86 [<c0103f20>] restore_nocheck+0x12/0x15 [<c0175416>] seq_printf+0x2e/0x52 [<c0192895>] show_tty_range+0x35/0x1f3 [<c0175416>] seq_printf+0x2e/0x52 [<c0192add>] show_tty_driver+0x8a/0x1d9 [<c01758f6>] seq_read+0x70/0x2ba [<c0175886>] seq_read+0x0/0x2ba [<c018d8e6>] proc_reg_read+0x63/0x9f [<c015e764>] vfs_read+0x7d/0xb5 [<c018d883>] proc_reg_read+0x0/0x9f [<c015eab1>] sys_read+0x41/0x6a [<c0103e4e>] sysenter_past_esp+0x5f/0x99 ======================= Code: 00 8b 4d 04 e9 44 ff ff ff 8d 4d 04 89 4c 24 50 8b 6d 00 81 fd ff 0f 00 00 b8 a4 c1 35 c0 0f 46 e8 8b 54 24 2c 89 e9 89 c8 eb 06 <80> 38 00 74 07 40 4a 83 fa ff 75 f4 29 c8 89 c6 8b 44 24 28 89 EIP: [<c01cefa7>] vsnprintf+0x3a4/0x5fc SS:ESP 0068:f31f5e68 Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
246 lines
5.9 KiB
C
246 lines
5.9 KiB
C
/*
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* proc_tty.c -- handles /proc/tty
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*
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* Copyright 1997, Theodore Ts'o
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*/
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#include <asm/uaccess.h>
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#include <linux/init.h>
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#include <linux/errno.h>
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#include <linux/time.h>
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#include <linux/proc_fs.h>
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#include <linux/stat.h>
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#include <linux/tty.h>
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#include <linux/seq_file.h>
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#include <linux/bitops.h>
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static int tty_ldiscs_read_proc(char *page, char **start, off_t off,
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int count, int *eof, void *data);
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/*
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* The /proc/tty directory inodes...
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*/
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static struct proc_dir_entry *proc_tty_ldisc, *proc_tty_driver;
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/*
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* This is the handler for /proc/tty/drivers
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*/
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static void show_tty_range(struct seq_file *m, struct tty_driver *p,
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dev_t from, int num)
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{
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seq_printf(m, "%-20s ", p->driver_name ? p->driver_name : "unknown");
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seq_printf(m, "/dev/%-8s ", p->name);
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if (p->num > 1) {
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seq_printf(m, "%3d %d-%d ", MAJOR(from), MINOR(from),
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MINOR(from) + num - 1);
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} else {
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seq_printf(m, "%3d %7d ", MAJOR(from), MINOR(from));
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}
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switch (p->type) {
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case TTY_DRIVER_TYPE_SYSTEM:
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seq_printf(m, "system");
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if (p->subtype == SYSTEM_TYPE_TTY)
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seq_printf(m, ":/dev/tty");
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else if (p->subtype == SYSTEM_TYPE_SYSCONS)
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seq_printf(m, ":console");
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else if (p->subtype == SYSTEM_TYPE_CONSOLE)
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seq_printf(m, ":vtmaster");
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break;
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case TTY_DRIVER_TYPE_CONSOLE:
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seq_printf(m, "console");
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break;
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case TTY_DRIVER_TYPE_SERIAL:
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seq_printf(m, "serial");
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break;
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case TTY_DRIVER_TYPE_PTY:
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if (p->subtype == PTY_TYPE_MASTER)
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seq_printf(m, "pty:master");
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else if (p->subtype == PTY_TYPE_SLAVE)
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seq_printf(m, "pty:slave");
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else
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seq_printf(m, "pty");
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break;
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default:
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seq_printf(m, "type:%d.%d", p->type, p->subtype);
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}
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seq_putc(m, '\n');
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}
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static int show_tty_driver(struct seq_file *m, void *v)
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{
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struct tty_driver *p = v;
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dev_t from = MKDEV(p->major, p->minor_start);
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dev_t to = from + p->num;
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if (&p->tty_drivers == tty_drivers.next) {
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/* pseudo-drivers first */
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seq_printf(m, "%-20s /dev/%-8s ", "/dev/tty", "tty");
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seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 0);
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seq_printf(m, "system:/dev/tty\n");
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seq_printf(m, "%-20s /dev/%-8s ", "/dev/console", "console");
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seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 1);
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seq_printf(m, "system:console\n");
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#ifdef CONFIG_UNIX98_PTYS
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seq_printf(m, "%-20s /dev/%-8s ", "/dev/ptmx", "ptmx");
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seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 2);
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seq_printf(m, "system\n");
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#endif
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#ifdef CONFIG_VT
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seq_printf(m, "%-20s /dev/%-8s ", "/dev/vc/0", "vc/0");
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seq_printf(m, "%3d %7d ", TTY_MAJOR, 0);
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seq_printf(m, "system:vtmaster\n");
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#endif
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}
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while (MAJOR(from) < MAJOR(to)) {
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dev_t next = MKDEV(MAJOR(from)+1, 0);
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show_tty_range(m, p, from, next - from);
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from = next;
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}
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if (from != to)
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show_tty_range(m, p, from, to - from);
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return 0;
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}
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/* iterator */
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static void *t_start(struct seq_file *m, loff_t *pos)
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{
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struct list_head *p;
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loff_t l = *pos;
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mutex_lock(&tty_mutex);
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list_for_each(p, &tty_drivers)
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if (!l--)
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return list_entry(p, struct tty_driver, tty_drivers);
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return NULL;
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}
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static void *t_next(struct seq_file *m, void *v, loff_t *pos)
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{
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struct list_head *p = ((struct tty_driver *)v)->tty_drivers.next;
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(*pos)++;
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return p==&tty_drivers ? NULL :
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list_entry(p, struct tty_driver, tty_drivers);
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}
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static void t_stop(struct seq_file *m, void *v)
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{
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mutex_unlock(&tty_mutex);
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}
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static struct seq_operations tty_drivers_op = {
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.start = t_start,
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.next = t_next,
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.stop = t_stop,
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.show = show_tty_driver
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};
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static int tty_drivers_open(struct inode *inode, struct file *file)
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{
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return seq_open(file, &tty_drivers_op);
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}
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static const struct file_operations proc_tty_drivers_operations = {
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.open = tty_drivers_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = seq_release,
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};
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/*
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* This is the handler for /proc/tty/ldiscs
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*/
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static int tty_ldiscs_read_proc(char *page, char **start, off_t off,
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int count, int *eof, void *data)
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{
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int i;
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int len = 0;
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off_t begin = 0;
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struct tty_ldisc *ld;
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for (i=0; i < NR_LDISCS; i++) {
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ld = tty_ldisc_get(i);
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if (ld == NULL)
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continue;
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len += sprintf(page+len, "%-10s %2d\n",
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ld->name ? ld->name : "???", i);
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tty_ldisc_put(i);
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if (len+begin > off+count)
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break;
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if (len+begin < off) {
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begin += len;
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len = 0;
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}
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}
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if (i >= NR_LDISCS)
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*eof = 1;
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if (off >= len+begin)
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return 0;
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*start = page + (off-begin);
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return ((count < begin+len-off) ? count : begin+len-off);
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}
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/*
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* This function is called by tty_register_driver() to handle
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* registering the driver's /proc handler into /proc/tty/driver/<foo>
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*/
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void proc_tty_register_driver(struct tty_driver *driver)
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{
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struct proc_dir_entry *ent;
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if ((!driver->read_proc && !driver->write_proc) ||
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!driver->driver_name ||
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driver->proc_entry)
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return;
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ent = create_proc_entry(driver->driver_name, 0, proc_tty_driver);
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if (!ent)
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return;
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ent->read_proc = driver->read_proc;
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ent->write_proc = driver->write_proc;
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ent->owner = driver->owner;
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ent->data = driver;
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driver->proc_entry = ent;
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}
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/*
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* This function is called by tty_unregister_driver()
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*/
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void proc_tty_unregister_driver(struct tty_driver *driver)
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{
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struct proc_dir_entry *ent;
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ent = driver->proc_entry;
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if (!ent)
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return;
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remove_proc_entry(driver->driver_name, proc_tty_driver);
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driver->proc_entry = NULL;
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}
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/*
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* Called by proc_root_init() to initialize the /proc/tty subtree
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*/
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void __init proc_tty_init(void)
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{
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struct proc_dir_entry *entry;
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if (!proc_mkdir("tty", NULL))
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return;
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proc_tty_ldisc = proc_mkdir("tty/ldisc", NULL);
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/*
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* /proc/tty/driver/serial reveals the exact character counts for
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* serial links which is just too easy to abuse for inferring
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* password lengths and inter-keystroke timings during password
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* entry.
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*/
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proc_tty_driver = proc_mkdir_mode("tty/driver", S_IRUSR | S_IXUSR, NULL);
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create_proc_read_entry("tty/ldiscs", 0, NULL, tty_ldiscs_read_proc, NULL);
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entry = create_proc_entry("tty/drivers", 0, NULL);
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if (entry)
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entry->proc_fops = &proc_tty_drivers_operations;
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}
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