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table(2)
NAME
table - Examine or update elements from a system table
SYNOPSIS
#include <sys/table.h>
int table(
long id,
long index,
void *addr,
long nel,
u_long lel );
PARAMETERS
id The ID of the system table that contains the element or elements.
index
The index of an element within the table.
addr
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.
nel 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.
lel The expected size of a single element.
DESCRIPTION
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:
TBL_U_TTYD
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.
TBL_UAREA
The U-area table. The index is by process ID. See the <user.h> header
file for the (pseudo) struct user that is returned.
TBL_LOADAVG
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 non-zero, 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.
TBL_INCLUDE_VERSION
The system include-file 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 kernel-dependent
programs. This table is examine only. It cannot be updated.
TBL_ARGUMENTS
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.
TBL_MAXUPRC
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.
TBL_PROCINFO
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.
TBL_THREADSTATES
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.
TBL_ENVIRONMENT
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.
TBL_SYSINFO
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.
TBL_DKINFO
The disk statistics table. The index is by disk number. This table is
examine only. It cannot be updated.
TBL_SWAPINFO
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).
TBL_TTYINFO
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.
TBL_MSGDS
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.
TBL_SEMDS
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.
TBL_SHMDS
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.
TBL_MSGINFO
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:
MSGINFO_MAX
The maximum message size
MSGINFO_MNB
The maximum number of bytes on the queue
MSGINFO_MNI
The number of message queue identifiers
MSGINFO_TQL
The number of system message headers
TBL_SEMINFO
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:
SEMINFO_MNI
The number of semaphore identifiers
SEMINFO_MSL
The maximum number of semaphores per identifier
SEMINFO_OPM
The maximum number of operations per semop() call
SEMINFO_UME
The maximum number of undo entries per process
SEMINFO_VMX
The semaphore maximum value
SEMINFO_AEM
The maximum adjust-on-exit value
TBL_SHMINFO
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:
SHMINFO_MAX
The maximum shared memory region size
SHMINFO_MIN
The minimum shared memory region size
SHMINFO_MNI
The number of shared memory identifiers
SHMINFO_SEG
The maximum number of attached shared memory regions per
process
TBL_INTR
The system interrupt information table. There is no index into the
table. This table is examine only. It cannot be updated.
TBL_FDSTAT
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.
RETURN VALUES
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.
ERRORS
[EFAULT]
The addr parameter specifies an invalid address.
[EINVAL]
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.
[ENXIO]
No such device or address.
[EPERM]
An attempt was made to change the maximum number of processes or the
account ID, and the caller was not the root user.
[ESRCH]
The process specified by a process ID index cannot be found.
[EWOULDBLOCK]
A call using TBL_ENVIRONMENT failed because of memory or lock
contention.
SEE ALSO
acct(2)
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