fs/proc/consoles.c

Source file repositories/reference/linux-study-clean/fs/proc/consoles.c

File Facts

System
Linux kernel
Corpus path
fs/proc/consoles.c
Extension
.c
Size
2510 bytes
Lines
117
Domain
Core OS
Bucket
VFS And Filesystem Core
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

if (driver) {
			dev = MKDEV(driver->major, driver->minor_start);
			dev += index;
		}
	}

	for (a = 0; a < ARRAY_SIZE(con_flags); a++)
		flags[a] = (con->flags & con_flags[a].flag) ?
			con_flags[a].name : ' ';
	flags[a] = 0;

	seq_setwidth(m, 21 - 1);
	seq_printf(m, "%s%d", con->name, con->index);
	seq_pad(m, ' ');
	seq_printf(m, "%c%c%c (%s)", con->read ? 'R' : '-',
		   ((con->flags & CON_NBCON) || con->write) ? 'W' : '-',
		   con->unblank ? 'U' : '-', flags);
	if (dev)
		seq_printf(m, " %4d:%d", MAJOR(dev), MINOR(dev));

	seq_putc(m, '\n');
	return 0;
}

static void *c_start(struct seq_file *m, loff_t *pos)
	__acquires(&console_mutex)
{
	struct console *con;
	loff_t off = 0;

	/*
	 * Hold the console_list_lock to guarantee safe traversal of the
	 * console list. SRCU cannot be used because there is no
	 * place to store the SRCU cookie.
	 */
	console_list_lock();
	for_each_console(con)
		if (off++ == *pos)
			break;

	return con;
}

static void *c_next(struct seq_file *m, void *v, loff_t *pos)
{
	struct console *con = v;

	++*pos;
	return hlist_entry_safe(con->node.next, struct console, node);
}

static void c_stop(struct seq_file *m, void *v)
	__releases(&console_mutex)
{
	console_list_unlock();
}

static const struct seq_operations consoles_op = {
	.start	= c_start,
	.next	= c_next,
	.stop	= c_stop,
	.show	= show_console_dev
};

static int __init proc_consoles_init(void)
{
	proc_create_seq("consoles", 0, NULL, &consoles_op);
	return 0;
}
fs_initcall(proc_consoles_init);

Annotation

Implementation Notes