incf(7tcp)

Synopsis

#include <sys/types.h>
#include <netinet/in_cfg.h>
#include <fcntl.h>
#include <paths.h>

fd = open(_PATH_INCONFIG, flags);

Description

Access to the INCF driver is via two ioctls: INCFG_RETRIEVE and INCFG_MODIFY. These ioctls are issued as I_STR ioctls (see streamio(7)).

Each ioctl operates on an in_config_t structure, which has the following definition:

   #define	MAX_SYM	256
   

   typedef struct in_config {
   	char	*ic_kname;          /* symbol name in kernel */
   	char	ic_name[MAX_SYM];   /* symbol name */
   	caddr_t	ic_addr;            /* kernel address */
   	u_long	ic_current;         /* current/default val */
   	u_long	ic_minimum;         /* minimum value */
   	u_long	ic_maximum;         /* maximum value */
   } in_config_t;

To retrieve current information about a kernel variable, copy the name of the desired variable into the ic_name field, and then issue an INCFG_RETRIEVE ioctl. The ic_current, ic_minimum, and ic_maximum fields will be filled in by the kernel.

To modify the value of a variable, copy the name of the desired variable into the ic_name field, assign the desired value to the ic_current field, and issue an INCFG_MODIFY ioctl. The kernel performs upper and lower bounds checking on the specified value. If the value is acceptable, the kernel configuration will be updated.

Files

/dev/cfg

/dev/inet/cfg

defined as _PATH_INCF in <paths.h>

Diagnostics

[EACCES]

when a non-root user attempts to modify a variable

[ENOENT]

when the specified variable cannot be found in the kernel

[EINVAL]

when the ioc_count of the argument is not the size of an in_config_t structure

[EDOM]

when the specified value is below the minimum allowed by the kernel

[ERANGE]

when the specified value is greater than the maximum allowed by the kernel

[ENXIO]

when another process has the configuration driver open

References

Notices