fs/proc/consoles.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2010 Werner Fink, Jiri Slaby
   4  */
   5
   6 #include <linux/console.h>
   7 #include <linux/kernel.h>
   8 #include <linux/proc_fs.h>
   9 #include <linux/seq_file.h>
  10 #include <linux/tty_driver.h>
  11
  12 /*
  13  * This is handler for /proc/consoles
  14  */
  15 static int show_console_dev(struct seq_file *m, void *v)
  16 {
  17         static const struct {
  18                 short flag;
  19                 char name;
  20         } con_flags[] = {
  21                 { CON_ENABLED,          'E' },
  22                 { CON_CONSDEV,          'C' },
  23                 { CON_BOOT,             'B' },
  24                 { CON_PRINTBUFFER,      'p' },
  25                 { CON_BRL,              'b' },
  26                 { CON_ANYTIME,          'a' },
  27         };
  28         char flags[ARRAY_SIZE(con_flags) + 1];
  29         struct console *con = v;
  30         unsigned int a;
  31         dev_t dev = 0;
  32
  33         if (con->device) {
  34                 const struct tty_driver *driver;
  35                 int index;
  36                 driver = con->device(con, &index);
  37                 if (driver) {
  38                         dev = MKDEV(driver->major, driver->minor_start);
  39                         dev += index;
  40                 }
  41         }
  42
  43         for (a = 0; a < ARRAY_SIZE(con_flags); a++)
  44                 flags[a] = (con->flags & con_flags[a].flag) ?
  45                         con_flags[a].name : ' ';
  46         flags[a] = 0;
  47
  48         seq_setwidth(m, 21 - 1);
  49         seq_printf(m, "%s%d", con->name, con->index);
  50         seq_pad(m, ' ');
  51         seq_printf(m, "%c%c%c (%s)", con->read ? 'R' : '-',
  52                         con->write ? 'W' : '-', con->unblank ? 'U' : '-',
  53                         flags);
  54         if (dev)
  55                 seq_printf(m, " %4d:%d", MAJOR(dev), MINOR(dev));
  56
  57         seq_putc(m, '\n');
  58         return 0;
  59 }
  60
  61 static void *c_start(struct seq_file *m, loff_t *pos)
  62 {
  63         struct console *con;
  64         loff_t off = 0;
  65
  66         console_lock();
  67         for_each_console(con)
  68                 if (off++ == *pos)
  69                         break;
  70
  71         return con;
  72 }
  73
  74 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
  75 {
  76         struct console *con = v;
  77         ++*pos;
  78         return con->next;
  79 }
  80
  81 static void c_stop(struct seq_file *m, void *v)
  82 {
  83         console_unlock();
  84 }
  85
  86 static const struct seq_operations consoles_op = {
  87         .start  = c_start,
  88         .next   = c_next,
  89         .stop   = c_stop,
  90         .show   = show_console_dev
  91 };
  92
  93 static int __init proc_consoles_init(void)
  94 {
  95         proc_create_seq("consoles", 0, NULL, &consoles_op);
  96         return 0;
  97 }
  98 fs_initcall(proc_consoles_init);