Examining the u-area of a process

In addition to the information about a process held in the process table, the user area (``u-area'') of each process contains information that the process uses when it is running. The process table is permanently resident in memory, but a process's u-area can be swapped out to disk. The form of a u-area corresponds to the user structure defined in <sys/user.h>.

When issued without arguments, the output of the user command contains information about the u-area of the process that is currently executing or, for a memory image, the process that was executing at the time of the panic. If the system was executing the idle loop (no process was runnable) at the time of the panic, there is no current process.

You can specify a process table slot number (obtained from the proc command) to user to view the u-area for that process. You can also specify a process ID (PID) as an argument if you prefix it with the # unary operator.

The following example shows selected portions of the full display obtained using the -f option:

> user -f 86
PER PROCESS USER AREA FOR PROCESS 86
USER ID's:        uid: 13297, gid: 1014, real uid: 13297, real gid: 1014
         supplementary gids: 1014 50
PROCESS TIMES:    user: 19, sys: 131, child user: 6085, child sys: 7785
PROCESS MISC:
         command: ksh, psargs: -ksh
         proc: P#86, cntrl tty:  58,6
         start: Fri Jul 15 15:23:21 1994
         mem: 1e5, type: exec su-user
         proc/text lock: none
         current directory: I#360
OPEN FILES AND POFILE FLAGS:
            [ 0]: F#216   r    [ 1]: F#216     w  [ 2]: F#216     w
            [ 3]: F#292   r    [ 4]: F#174        [ 6]: F#156
            [31]: F#246 c r w 
FILE I/O:
         u_base: 0x45164c, file offset: 10302696, bytes: 1230
         segment: data, cmask: 0022, ulimit: 2097151
         file mode(s): read
SIGNAL DISPOSITION:
         sig#      signal oldmask sigmask
            1:     0x6ffc    -     1
            2:     0x7718    -     2
...

USER ID's

Shows the real and effective IDs of the user running the process.

PROCESS MISC

Shows miscellaneous information about the process. The fields command and psargs tell you the name of the program and the first few arguments to the command. The start time shows the actual clock time when the process was initialized.

OPEN FILES AND POFILE FLAGS

Tells you the files that the process had open, and the file descriptors involved. The file descriptors in use by the program are in shown square brackets; the F# numbers represent slot numbers in the open file table and can be used as arguments to the file command. For example, file descriptor 1 usually corresponds to the standard output (stdout) unless this was redefined. In this example, it points to slot 216 of the open file table; you can use the command file 216 to view this entry.

SIGNAL DISPOSITION

Shows the behavior defined for all signals. See the signal(S) manual page for a definition of the signal numbers.