make_dev(9)

NAME

make_dev, make_dev_alias, destroy_dev, dev_depends - manage

cdev's and
DEVFS registration for devices

SYNOPSIS

#include <sys/param.h>
#include <sys/conf.h>
struct cdev
make_dev(struct  cdevsw *cdevsw, int minor, uid_t uid, gid_t
gid,
        int perms, const char *fmt, ...);
struct cdev
make_dev_alias(struct cdev pdev, const char *fmt, ...);
void
destroy_dev(struct cdev dev);
void
dev_depends(struct cdev pdev, struct cdev cdev);

DESCRIPTION

The make_dev() function creates a cdev structure for a new

device. If
DEVFS is available, it is also notified of the presence of

the new
device. The device will be owned by uid, with the group

ownership as
gid, and with the name as specified in name. The permis

sions of the file
specified in perms are defined in

#define S_IRWXU 0000700 /* RWX mask for owner */
#define S_IRUSR 0000400 /* R for owner */
#define S_IWUSR 0000200 /* W for owner */
#define S_IXUSR 0000100 /* X for owner */

#define S_IRWXG 0000070 /* RWX mask for group */
#define S_IRGRP 0000040 /* R for group */
#define S_IWGRP 0000020 /* W for group */
#define S_IXGRP 0000010 /* X for group */

#define S_IRWXO 0000007 /* RWX mask for other */
#define S_IROTH 0000004 /* R for other */
#define S_IWOTH 0000002 /* W for other */
#define S_IXOTH 0000001 /* X for other */

#define S_ISUID 0004000 /* set user id on execution

*/
#define S_ISGID 0002000 /* set group id on execu

tion */
#define S_ISVTX 0001000 /* sticky bit */
#ifndef _POSIX_SOURCE
#define S_ISTXT 0001000
#endif

The make_dev_alias() function takes the returned cdev from

make_dev() and
makes another (aliased) name for this device. It is an er

ror to call
make_dev_alias() prior to calling make_dev().

The destroy_dev() function takes the returned cdev from

make_dev() and
destroys the registration for that device. Do not call

destroy_dev() on
devices that were created with make_dev_alias().

The dev_depends() function establishes a parent-child rela

tionship
between two devices. The net effect is that a destroy_dev()

of the parent device will also result in the destruction of the child

device(s), if
any exist. A device may simultaneously be a parent and a

child, so it is
possible to build a complete hierarchy.

SEE ALSO

devfs(5)

HISTORY

The make_dev() and destroy_dev() functions first appeared in

FreeBSD 4.0.
The function make_dev_alias() first appeared in FreeBSD 4.1.

The function dev_depends() first appeared in FreeBSD 5.0.

BSD March 28, 2005

BSD