| 1 | |
| 2 | |
| 3 | * Copyright (c) 2010 Werner Fink, Jiri Slaby
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| 4 |
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| 5 |
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| 6 | #include <linux/console.h>
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| 7 | #include <linux/kernel.h>
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| 8 | #include <linux/proc_fs.h>
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| 9 | #include <linux/seq_file.h>
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| 10 | #include <linux/tty_driver.h>
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| 11 |
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| 12 | |
| 13 | * This is handler for /proc/consoles
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| 14 |
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| 15 | static int show_console_dev(struct seq_file *m, void *v)
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| 16 | {
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| 17 | static const struct {
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| 18 | short flag;
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| 19 | char name;
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| 20 | } con_flags[] = {
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| 21 | { CON_ENABLED, 'E' },
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| 22 | { CON_CONSDEV, 'C' },
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| 23 | { CON_BOOT, 'B' },
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| 24 | { CON_NBCON, 'N' },
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| 25 | { CON_PRINTBUFFER, 'p' },
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| 26 | { CON_BRL, 'b' },
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| 27 | { CON_ANYTIME, 'a' },
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| 28 | };
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| 29 | char flags[ARRAY_SIZE(con_flags) + 1];
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| 30 | struct console *con = v;
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| 31 | unsigned int a;
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| 32 | dev_t dev = 0;
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| 33 |
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| 34 | if (con->device) {
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| 35 | const struct tty_driver *driver;
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| 36 | int index;
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| 37 |
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| 38 | |
| 39 | * Take console_lock to serialize device() callback with
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| 40 | * other console operations. For example, fg_console is
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| 41 | * modified under console_lock when switching vt.
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| 42 |
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| 43 | console_lock();
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| 44 | driver = con->device(con, &index);
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| 45 | console_unlock();
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| 46 |
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| 47 | if (driver) {
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| 48 | dev = MKDEV(driver->major, driver->minor_start);
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| 49 | dev += index;
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| 50 | }
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| 51 | }
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| 52 |
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| 53 | for (a = 0; a < ARRAY_SIZE(con_flags); a++)
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| 54 | flags[a] = (con->flags & con_flags[a].flag) ?
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| 55 | con_flags[a].name : ' ';
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| 56 | flags[a] = 0;
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| 57 |
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| 58 | seq_setwidth(m, 21 - 1);
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| 59 | seq_printf(m, "%s%d", con->name, con->index);
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| 60 | seq_pad(m, ' ');
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| 61 | seq_printf(m, "%c%c%c (%s)", con->read ? 'R' : '-',
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| 62 | ((con->flags & CON_NBCON) || con->write) ? 'W' : '-',
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| 63 | con->unblank ? 'U' : '-', flags);
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| 64 | if (dev)
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| 65 | seq_printf(m, " %4d:%d", MAJOR(dev), MINOR(dev));
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| 66 |
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| 67 | seq_putc(m, '\n');
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| 68 | return 0;
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| 69 | }
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| 70 |
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| 71 | static void *c_start(struct seq_file *m, loff_t *pos)
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| 72 | __acquires(&console_mutex)
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| 73 | {
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| 74 | struct console *con;
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| 75 | loff_t off = 0;
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| 76 |
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| 77 | |
| 78 | * Hold the console_list_lock to guarantee safe traversal of the
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| 79 | * console list. SRCU cannot be used because there is no
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| 80 | * place to store the SRCU cookie.
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| 81 |
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| 82 | console_list_lock();
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| 83 | for_each_console(con)
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| 84 | if (off++ == *pos)
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| 85 | break;
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| 86 |
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| 87 | return con;
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| 88 | }
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| 89 |
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| 90 | static void *c_next(struct seq_file *m, void *v, loff_t *pos)
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| 91 | {
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| 92 | struct console *con = v;
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| 93 |
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| 94 | ++*pos;
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| 95 | return hlist_entry_safe(con->node.next, struct console, node);
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| 96 | }
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| 97 |
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| 98 | static void c_stop(struct seq_file *m, void *v)
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| 99 | __releases(&console_mutex)
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| 100 | {
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| 101 | console_list_unlock();
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| 102 | }
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| 103 |
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| 104 | static const struct seq_operations consoles_op = {
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| 105 | .start = c_start,
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| 106 | .next = c_next,
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| 107 | .stop = c_stop,
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| 108 | .show = show_console_dev
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| 109 | };
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| 110 |
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| 111 | static int __init proc_consoles_init(void)
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| 112 | {
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| 113 | proc_create_seq("consoles", 0, NULL, &consoles_op);
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| 114 | return 0;
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| 115 | }
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| 116 | fs_initcall(proc_consoles_init);
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