uadmin
provides control for basic administrative functions.
This system call is tightly coupled to the system administrative procedures
and is not intended for general use.
The calling process must have the P_SYSOPS privilege.
The argument
mdep
is provided for machine-dependent use;
for example, see A_SETCONFIG, below.
cmd
can take on one of the following values:
A_SHUTDOWN
The system is shut down.
All user processes are killed, the buffer cache is flushed, and the root
file system is unmounted.
The action to be taken after the system has been shut down is specified by
fcn.
The functions are generic;
the hardware capabilities vary on
specific machines.
AD_HALT
Halt the processor and turn off the power.
AD_BOOT
Reboot the system, using /stand/unix.
AD_IBOOT
Interactive reboot; the system goes to firmware mode and,
if the user strikes any key while the system logo is displayed,
the system prompts for a bootable program name.
If fcn is not supplied or is invalid, AD_IBOOT is used as
the default.
A_REBOOT
The system stops immediately without any further processing.
The action to be taken next is specified by
fcn
as above.
A_REMOUNT
The root file system is mounted again after having been fixed.
This should be used only during the startup process.
A_CLOCK
The argument fcn is the number of
seconds to adjust the clock.
A_SETCONFIG
Currently this command supports the single function
AD_PANICBOOT,
which determines the system's behavior following a system panic.
If mdep is 1,
the system will automatically reboot following a panic;
if mdep is 0,
the system will remain in firmware mode following a panic.
Return values
If uadmin succeeds, it returns a value that depends on
cmd
as follows:
A_SHUTDOWN
Never returns.
A_REBOOT
Never returns.
A_REMOUNT
0
A_CLOCK
0
A_SETCONFIG
0
If uadmin fails, it returns -1 and sets errno
to identify the error.
Errors
uadmin
fails if any of the following are true:
EPERM
The calling process does not have the P_SYSOPS privilege.