Constant Devices

Constant devices. More...

Functions
static uint64_t	const_one_read (file_t *file, void *buffer, uint64_t count, uint64_t *offset)
static void *	const_one_mmap (file_t *file, void *addr, uint64_t length, uint64_t *offset, pml_flags_t flags)
static uint64_t	const_zero_read (file_t *file, void *buffer, uint64_t count, uint64_t *offset)
static void *	const_zero_mmap (file_t *file, void *addr, uint64_t length, uint64_t *offset, pml_flags_t flags)
static uint64_t	const_null_read (file_t *file, void *buffer, uint64_t count, uint64_t *offset)
static uint64_t	const_null_write (file_t *file, const void *buffer, uint64_t count, uint64_t *offset)
static uint64_t	const_init (void)
static void	const_deinit (void)

Variables
static dentry_t *	oneFile
static dentry_t *	zeroFile
static dentry_t *	nullFile
static file_ops_t	oneOps
static file_ops_t	zeroOps
static file_ops_t	nullOps

Detailed Description

Constant devices.

This module provides the constant devices which provide user space with its primary means of allocating memory and obtaining constant data.

The constant devices are exposed under the /dev directory:

• /dev/one: A readable and mappable file that returns bytes with all bits set to 1.
• /dev/zero: A readable and mappable file that returns bytes with all bits set to 0.
• /dev/null: A readable and writable file that discards all written data and returns EOF on read.

Function Documentation

const_deinit()

static void const_deinit ( void  )

static

Definition at line 143 of file const.c.

References DEREF, nullFile, oneFile, and zeroFile.

Referenced by _module_procedure().

const_init()

static uint64_t const_init ( void  )

static

Definition at line 114 of file const.c.

References DEREF, ERR, LOG_ERR, NULL, nullFile, nullOps, oneFile, oneOps, sysfs_file_new(), zeroFile, and zeroOps.

Referenced by _module_procedure().

const_null_read()

static uint64_t const_null_read ( file_t *  file, void *  buffer, uint64_t  count, uint64_t *  offset  )

static

Definition at line 91 of file const.c.

References buffer, count, and file.

const_null_write()

static uint64_t const_null_write ( file_t *  file, const void *  buffer, uint64_t  count, uint64_t *  offset  )

static

Definition at line 100 of file const.c.

References buffer, count, and file.

const_one_mmap()

static void * const_one_mmap ( file_t *  file, void *  addr, uint64_t  length, uint64_t *  offset, pml_flags_t  flags  )

static

Definition at line 42 of file const.c.

References file, memset(), NULL, sched_process(), vmm_alloc(), and VMM_ALLOC_NONE.

const_one_read()

static uint64_t const_one_read ( file_t *  file, void *  buffer, uint64_t  count, uint64_t *  offset  )

static

Definition at line 33 of file const.c.

References buffer, count, file, and memset().

const_zero_mmap()

static void * const_zero_mmap ( file_t *  file, void *  addr, uint64_t  length, uint64_t *  offset, pml_flags_t  flags  )

static

Definition at line 71 of file const.c.

References file, memset(), NULL, sched_process(), vmm_alloc(), and VMM_ALLOC_NONE.

const_zero_read()

static uint64_t const_zero_read ( file_t *  file, void *  buffer, uint64_t  count, uint64_t *  offset  )

static

Definition at line 62 of file const.c.

References buffer, count, file, and memset().

Variable Documentation

nullFile

dentry_t* nullFile

static

Definition at line 31 of file const.c.

Referenced by const_deinit(), and const_init().

nullOps

file_ops_t nullOps

static

Initial value:

= {
    .read = const_null_read,
    .write = const_null_write,
}

Definition at line 109 of file const.c.

Referenced by const_init().

oneFile

dentry_t* oneFile

static

Definition at line 29 of file const.c.

Referenced by const_deinit(), and const_init().

oneOps

file_ops_t oneOps

static

Initial value:

= {
    .read = const_one_read,
    .mmap = const_one_mmap,
}

Definition at line 57 of file const.c.

Referenced by const_init().

zeroFile

dentry_t* zeroFile

static

Definition at line 30 of file const.c.

Referenced by const_deinit(), and const_init().

zeroOps

file_ops_t zeroOps

static

Initial value:

= {
    .read = const_zero_read,
    .mmap = const_zero_mmap,
}

Definition at line 86 of file const.c.

Referenced by const_init().