fs/proc/proc_console.c

   1 /*
   2  * Copyright (c) 2010 Werner Fink, Jiri Slaby
   3  *
   4  * Licensed under GPLv2
   5  */
   6
   7 #include <linux/console.h>
   8 #include <linux/kernel.h>
   9 #include <linux/proc_fs.h>
  10 #include <linux/seq_file.h>
  11 #include <linux/tty_driver.h>
  12
  13 /*
  14  * This is handler for /proc/consoles
  15  */
  16 static int show_console_dev(struct seq_file *m, void *v)
  17 {
  18         static const struct {
  19                 short flag;
  20                 char name;
  21         } con_flags[] = {
  22                 { CON_ENABLED,          'E' },
  23                 { CON_CONSDEV,          'C' },
  24                 { CON_BOOT,             'B' },
  25                 { CON_PRINTBUFFER,      'p' },
  26                 { CON_BRL,              'b' },
  27                 { CON_ANYTIME,          'a' },
  28         };
  29         char flags[ARRAY_SIZE(con_flags) + 1];
  30         struct console *con = v;
  31         unsigned int a;
  32         int len;
  33         dev_t dev = 0;
  34
  35         if (con->device) {
  36                 const struct tty_driver *driver;
  37                 int index;
  38                 driver = con->device(con, &index);
  39                 if (driver) {
  40                         dev = MKDEV(driver->major, driver->minor_start);
  41                         dev += index;
  42                 }
  43         }
  44
  45         for (a = 0; a < ARRAY_SIZE(con_flags); a++)
  46                 flags[a] = (con->flags & con_flags[a].flag) ?
  47                         con_flags[a].name : ' ';
  48         flags[a] = 0;
  49
  50         seq_printf(m, "%s%d%n", con->name, con->index, &len);
  51         len = 21 - len;
  52         if (len < 1)
  53                 len = 1;
  54         seq_printf(m, "%*c%c%c%c (%s)", len, ' ', con->read ? 'R' : '-',
  55                         con->write ? 'W' : '-', con->unblank ? 'U' : '-',
  56                         flags);
  57         if (dev)
  58                 seq_printf(m, " %4d:%d", MAJOR(dev), MINOR(dev));
  59
  60         seq_printf(m, "\n");
  61
  62         return 0;
  63 }
  64
  65 static void *c_start(struct seq_file *m, loff_t *pos)
  66 {
  67         struct console *con;
  68         loff_t off = 0;
  69
  70         acquire_console_sem();
  71         for_each_console(con)
  72                 if (off++ == *pos)
  73                         break;
  74
  75         return con;
  76 }
  77
  78 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
  79 {
  80         struct console *con = v;
  81         ++*pos;
  82         return con->next;
  83 }
  84
  85 static void c_stop(struct seq_file *m, void *v)
  86 {
  87         release_console_sem();
  88 }
  89
  90 static const struct seq_operations consoles_op = {
  91         .start  = c_start,
  92         .next   = c_next,
  93         .stop   = c_stop,
  94         .show   = show_console_dev
  95 };
  96
  97 static int consoles_open(struct inode *inode, struct file *file)
  98 {
  99         return seq_open(file, &consoles_op);
 100 }
 101
 102 static const struct file_operations proc_consoles_operations = {
 103         .open           = consoles_open,
 104         .read           = seq_read,
 105         .llseek         = seq_lseek,
 106         .release        = seq_release,
 107 };
 108
 109 static int register_proc_consoles(void)
 110 {
 111         proc_create("consoles", 0, NULL, &proc_consoles_operations);
 112         return 0;
 113 }
 114 module_init(register_proc_consoles);