openproc man page

openproc, closeproc — initialize process information from /proc/

Synopsis

#include <proc/readproc.h>

PROCTAB* openproc (int flags, ... );
void closeproc (PROCTAB* PT);

Synopsis

The openproc function initializes a PROCTAB structure which can be used by iterated readproc calls to get information on current processes. Depending on flags, openproc may need a second argument or a second and third argument (see below).

closeproc closes all files opened by openproc and deallocates the memory allocated by openproc.

The PROCTAB structure is defined in <proc/readproc.h>

Return Value

openproc returns a pointer to a PROCTAB structure, or NULL if an error occurs. This usually means that /proc cannot be read by the process.

Flags

The behaviour of openproc is controlled by the following set of flags, which may be ORed together. There are three different kinds of flags. The first group of flags determins which information gets read from /proc/#pid for each process. The second group of flags (of which only one can be enacted for a opendir call) restricts which processes information is read for by providing a list of criteria. The third group of flags restricts this as well, but doesn't need arguments. These may be used together again.

PROC_FILLMEM
read information from /proc/#pid/statm
PROC_FILLCOM
allocate cmdline part of proc_t and read information from /proc/#pid/cmdline
PROC_FILLENV
allocate environ part of proc_t and read information from /proc/#pid/environ
PROC_FILLUSR
resolve user ids to names via /etc/passwd
PROC_FILLGRP
resolve group ids to names via /etc/group
PROC_FILLSTATUS
read information from /proc/#pid/status
PROC_FILLSTAT
read information from /proc/#pid/stat
PROC_FILLWCHAN
do WCHAN lookup
PROC_FILLARG
equivalent to PROC_FILLCOM
PROC_FILLCGROUP
alloc and fill in cgroup
PROC_FILLSUPGRP
resolve supplementary group id -> group name
PROC_FILLOOM
fill in proc_t oom_score and oom_adj
PROC_FILLNS
fill in proc_t namespace information
PROC_FILLSYSTEMD
fill in proc_t systemd information
PROC_LOOSE_TASKS
threat threads as if they were processes
PROC_PID (2nd argument pid_t* pidlist)
lookup only processes whose pid is contained in pidlist (the list is terminated with 0)
PROC_UID (arguments uid_t* uidlist, int n)
lookup only processes whose user id is contained in uidlist (where n is the number of uids contained in the list)
PROC_EDITCGRPCVT
edit cgroup as single vector
PROC_EDITCMDLCVT
edit cmdline as single vector
PROC_EDITENVRCVT
edit environ as single vector

Note

Only one of the flags needing additional arguments (PROC_{PID,UID}) may be used at a time.

See Also

readproc(3), readproctab(3), /proc/, /usr/include/proc/readproc.h,

Reporting Bugs

Please send bug reports to procps@freelists.org

Referenced By

readproc(3), readproctab(3).

14 July 2014 Linux Manpage Linux Programmer's Manual