table - Examine or update elements from a system table
#include <sys/table.h>
int table(
long id,
long index,
void *addr,
long nel,
u_long lel );
The ID of the system table that contains the element or
elements. The index of an element within the table. The
address of a struct (or a struct array) of the appropriate
type to copy the element values to (on examine) or from
(on update). The various structure layouts are described
in /usr/include/sys/table.h. A signed number that specifies
how many elements to copy and in which direction. A
positive value copies the elements from the kernel to
addr. A negative value copies the elements from addr to
the kernel. The expected size of a single element.
The table() interface is used to examine or update one or
more elements in the system table. The system table is
specified by id and the starting element is specified by
index.
The table() interface copies the element value or values
to or from the specified addr. The nel parameter specifies
the number of elements to copy, starting from index. A
positive value indicates an examine operation. The elements
are copied from the kernel to addr. A negative value
indicates an update operation. The elements are copied
from addr to the kernel.
The lel parameter specifies the expected element size. If
multiple elements are specified, successive addresses are
calculated for addr by incrementing it by lel for each
element copied. If the size of a given element is larger
than lel, table() truncates excess data on an update (from
addr to the kernel) and stores only the expected size on
an examine (from the kernel to addr). If the size of a
given element is smaller than lel, table() copies only the
valid data on an update and pads the element value on an
examine.
The table() interface guarantees that an update operation
will not change the offset and size of any field within an
element. New fields are added only at the end of an element.
The table() interface returns a count of the elements
examined or updated. The id value TBL_PROCINFO allows you
to determine the actual number of elements in a table
before requesting any data; in this case, call table()
with lel set to zero (0) and nel to the maximum positive
integer.
The id parameter must specify one of the following tables,
each of which has a structure in <sys/table.h>, unless
otherwise noted: The controlling terminal device number
table. The index is by process ID and exactly one element
can be requested. If the process ID is zero (0), the current
process is indexed. Only 0 and the current process
ID are supported. The element is of type dev_t as defined
in <sys/types.h>. This table is examine only. It cannot
be updated. The U-area table. The index is by process ID.
See the <user.h> header file for the (pseudo) struct user
that is returned. The system load average vector (pseudo)
table. In this case, index must be zero (0) and exactly
one element can be requested.
If the scale is zero (0), the load average vector
is the floating point variant. If the size is nonzero,
the load average vector has been scaled by
the indicated factor (typically 1000) to produce
the long integer variant. This table is examine
only. It cannot be updated. The system includefile
version-number (pseudo) table. The index value
must be zero (0) and exactly one element can be
requested. The include-file version is a unique
integer. It identifies the layout of kernel data
structures that are imported by certain kerneldependent
programs. This table is examine only. It
cannot be updated. The process command argument
table containing the saved arguments for processes.
The index value is by process ID only and exactly
one element can be requested. Arguments for processes
other than the current process can be
accessed only by the root user. This table is examine
only. It cannot be updated.
This table contains all the command line arguments
for the process. Specify the process id in the
index argument. The addr argument points to a
buffer into which the command line arguments are
placed.
The amount of buffer space needed for the command
line arguments depends on the total length of all
the arguments from the process being examined.
Specify the size of the user buffer with the lel
argument. If the buffer is not large enough to
accept the complete argument list, the given length
of the buffer is copied.
The arguments are placed in the buffer as a series
of null-terminated strings, in argument order. The
maximum process count per user ID table. The index
is by process ID and exactly one element can be
requested. If the process ID is zero (0), the current
process is indexed. Only 0 and the current
process ID are supported. The element is of the
short integer type.
The maximum count includes all processes running
under the current user ID even though the limit
affects only the current process and any children
created with that limit in effect. The limit can be
changed only by the root user. The process status
information table. The index value is an offset
into a table of processes. Status information for
processes other than the current process can be
accessed only by the root user. This table is
examine only and cannot be updated.
The TBL_PROCINFO id value lets you determine the
actual number of elements in a table before you
request any data. You call table() with the lel
argument set to zero, index set to zero, and the
nel argument set to the maximum positive integer.
The return is the number of elements in the table.
The current count of threads and their states. The
index value may be either a single process ID, or
zero (0) to count all process IDs. Only the root
user can obtain information on a single process ID
that is not the current process. Only one element
should be requested (only one is available). This
table is examine only. It cannot be updated. The
process environment table. The index value is by
process ID and exactly one element can be
requested. Environment information for processes
other than the current process can be accessed only
by the root user. This table is examine only. It
cannot be updated. The system time information
table. The index must be zero (0) and exactly one
element can be requested. The system information
table contains ticks of time accumulated in the
various system states: user, nice, system, and
idle. The system tick frequency and profiling (if
configured) frequency are also provided for conversion
from ticks to time values. This table is examine
only. It cannot be updated. The disk statistics
table. The index is by disk number. This table
is examine only. It cannot be updated. The system
swap device list information table. This table is
examine only. It cannot be updated.
If index is positive or zero (0), the swap device
information for the entry in the swap device list
is returned.
If index is less than zero (0), the amount of total
swap space configured and amount of total free
space on the system is returned. In addition, the
options member contains the value of vm_swap_eager
system attribute and the dev field contains the
lazy swap device number (if lazy swap is set) or
zero (0) (if eager swap is set). The TTY statistics
table. The index value must be zero (0) and
exactly one element can be requested. This table is
examine only. It cannot be updated. The message
queue ID table. The index value is the index into
the queue array. Each element of the array is a
msqid_ds structure as defined in <sys/msg.h>. This
table is examine only. Its elements cannot be
updated. The semaphore ID table. The index value
is the index into the array of semaphore IDs. Each
element is a semid_ds structure as defined in
<sys/sem.h>. This table is examine only. Its elements
cannot be updated. The shared memory region
ID table. The index value is the index into the
array of shared memory region IDs. Each element is
a shmid_ds structure as defined in <sys/shm.h>.
This table is examine only. Its elements cannot be
updated. The message information table. This table
is examine only. Its elements cannot be updated.
The message information structure is defined in
<sys/msg.h>.
The index is by field positions within the message
information structure, as follows: The maximum message
size The maximum number of bytes on the queue
The number of message queue identifiers The number
of system message headers The semaphore information
table. This table is examine only. It cannot be
updated. The semaphore information structure is
defined in <sys/sem.h>.
The index value is the field position within the
semaphore information structure as follows: The
number of semaphore identifiers The maximum number
of semaphores per identifier The maximum number of
operations per semop() call The maximum number of
undo entries per process The semaphore maximum
value The maximum adjust-on-exit value The shared
memory information table. This table is examine
only. It cannot be updated. The shared memory
information structure is defined in <sys/shm.h>.
The index value is the field position within the
shared memory information structure, as follows:
The maximum shared memory region size The minimum
shared memory region size The number of shared memory
identifiers The maximum number of attached
shared memory regions per process The system interrupt
information table. There is no index into the
table. This table is examine only. It cannot be
updated. The user file table. The index is by
process ID and exactly one element can be
requested. The addr argument is of type struct
stat. The nel argument specifies the file descriptor.
This table provides stat information on the
specified descriptor for the specified process ID.
Information on processes other than the current
process can be accessed only by the root user. This
table is examine only.
A positive return value indicates that the call succeeded
for that number of elements. A return value of -1 indicates
failure, in which case, errno is set to indicate the
error.
The addr parameter specifies an invalid address. One of
the following applies: The table specified by id is not
defined. The index value is not valid for the specified
table. The specified table allows only an index of the
current process ID with exactly one element. Some other
index or element number was specified. An element length
of zero (0) was supplied for the TBL_ARGUMENTS table. An
attempt was made to update an examine-only table. No such
device or address. An attempt was made to change the maximum
number of processes or the account ID, and the caller
was not the root user. The process specified by a process
ID index cannot be found. A call using TBL_ENVIRONMENT
failed because of memory or lock contention.
acct(2)
table(2)
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