sad(7)

sad -- STREAMS Administrative Driver

Synopsis

#include <sys/types.h> 
#include <sys/conf.h> 
#include <sys/sad.h> 
#include <sys/stropts.h> 
 
int ioctl (int fildes, int command, . . . /* arg */);

Description

The STREAMS Administrative Driver provides an interface for applications to perform administrative operations on STREAMS modules and drivers. The interface is provided through ioctl(2) commands. Privileged operations may access the sad driver via /dev/sad/admin. Unprivileged operations may access the sad driver via /dev/sad/user.

fildes is an open file descriptor that refers to the sad driver. command determines the control function to be performed as described below. arg represents additional information that is needed by this command. The type of arg depends upon the command, but it is generally an integer or a pointer to a command-specific data structure.

Commands

The autopush facility [see autopush(1M)] allows one to configure a list of modules to be automatically pushed on a stream when a driver is first opened. Autopush is controlled by the next commands.

SAD_SAP

Allows the administrator to configure the autopush information for the given device. arg points to a strapush structure which contains the following members:

           uint   sap_cmd; 
           long   sap_major; 
           long   sap_minor; 
           long   sap_lastminor; 
           long   sap_npush; 
           uint   sap_list[MAXAPUSH] [FMNAMESZ + 1];

The sap_cmd field indicates the type of configuration being done. It may take on one of the following values:

SAP_ONE: Configure one minor device of a driver.
SAP_RANGE: Configure a range of minor devices of a driver.
SAP_ALL: Configure all minor devices of a driver.
SAP_CLEAR: Undo configuration information for a driver.

The sap_major field is the major device number of the device to be configured. The sap_minor field is the minor device number of the device to be configured. The sap_lastminor field is used only with the SAP_RANGE command, with which a range of minor devices between sap_minor and sap_lastminor, inclusive, are to be configured. The minor fields have no meaning for the SAP_ALL command. The sap_npush field indicates the number of modules to be automatically pushed when the device is opened. It must be less than or equal to MAXAPUSH, defined in sad.h. It must also be less than or equal to NSTRPUSH, the maximum number of modules that can be pushed on a stream, defined in the kernel master file. The field sap_list is an array of module names to be pushed in the order in which they appear in the list.

When using the SAP_CLEAR command, the user sets only sap_major and sap_minor. This will undo the configuration information for any of the other commands. If a previous entry was configured as SAP_ALL, sap_minor should be set to zero. If a previous entry was configured as SAP_RANGE, sap_minor should be set to the lowest minor device number in the range configured.

On failure, errno is set to the following value:

EFAULT: arg points outside the allocated address space.
EINVAL: The major device number is invalid, the number of modules is invalid, or the list of module names is invalid.
ENOSTR: The major device number does not represent a STREAMS driver.
EEXIST: The major-minor device pair is already configured.
ERANGE: The command is SAP_RANGE and sap_lastminor is not greater than sap_minor, or the command is SAP_CLEAR and sap_minor is not equal to the first minor in the range.
ENODEV: The command is SAP_CLEAR and the device is not configured for autopush.
ENOSR: An internal autopush data structure cannot be allocated.

SAD_GAP

Allows any user to query the sad driver to get the autopush configuration information for a given device. arg points to a strapush structure as described in the previous command.

The user should set the sap_major and sap_minor fields of the strapush structure to the major and minor device numbers, respectively, of the device in question. On return, the strapush structure will be filled in with the entire information used to configure the device. Unused entries in the module list will be zero-filled.

On failure, errno is set to one of the following values:

EFAULT: arg points outside the allocated address space.
EINVAL: The major device number is invalid.
ENOSTR: The major device number does not represent a STREAMS driver.
ENODEV: The device is not configured for autopush.

SAD_VML

Allows any user to validate a list of modules (for example, to see if they are installed on the system). arg is a pointer to a str_list structure with the following members:

           int                sl_nmods; 
           struct str_mlist   *sl_modlist;

The str_mlist structure has the following member:

           char    l_name[FMNAMESZ+1];

sl_nmods indicates the number of entries the user has allocated in the array and sl_modlist points to the array of module names. The return value is 0 if the list is valid, 1 if the list contains an invalid module name, or -1 on failure. On failure, errno is set to one of the following values:

EFAULT: arg points outside the allocated address space.
EINVAL: The sl_nmods field of the str_list structure is less than or equal to zero.

Return values

Unless specified otherwise above, the return value from ioctl is 0 upon success and -1 upon failure with errno set as indicated.

References

intro(2), ioctl(2), open(2)