Section (2) acct
Name
acct — switch process accounting on or off
Synopsis
#include <unistd.h>
int
acct( |
const char *filename) ; |
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Note | |||||
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DESCRIPTION
The acct
() system call
enables or disables process accounting. If called with the
name of an existing file as its argument, accounting is
turned on, and records for each terminating process are
appended to filename
as it terminates. An argument of NULL causes accounting to be
turned off.
RETURN VALUE
On success, zero is returned. On error, −1 is
returned, and errno
is set
appropriately.
ERRORS
- EACCES
-
Write permission is denied for the specified file, or search permission is denied for one of the directories in the path prefix of
filename
(see also path_resolution(7)), orfilename
is not a regular file. - EFAULT
-
filename
points outside your accessible address space. - EIO
-
Error writing to the file
filename
. - EISDIR
-
filename
is a directory. - ELOOP
-
Too many symbolic links were encountered in resolving
filename
. - ENAMETOOLONG
-
filename
was too long. - ENFILE
-
The system-wide limit on the total number of open files has been reached.
- ENOENT
-
The specified file does not exist.
- ENOMEM
-
Out of memory.
- ENOSYS
-
BSD process accounting has not been enabled when the operating system kernel was compiled. The kernel configuration parameter controlling this feature is
CONFIG_BSD_PROCESS_ACCT
. - ENOTDIR
-
A component used as a directory in
filename
is not in fact a directory. - EPERM
-
The calling process has insufficient privilege to enable process accounting. On Linux, the
CAP_SYS_PACCT
capability is required. - EROFS
-
filename
refers to a file on a read-only filesystem. - EUSERS
-
There are no more free file structures or we ran out of memory.
NOTES
No accounting is produced for programs running when a system crash occurs. In particular, nonterminating processes are never accounted for.
The structure of the records written to the accounting file is described in acct(5).
COLOPHON
This page is part of release 4.16 of the Linux man-pages
project. A
description of the project, information about reporting bugs,
and the latest version of this page, can be found at
https://www.kernel.org/doc/man−pages/.
Copyright (c) 1993 Michael Haardt (michaelmoria.de), Fri Apr 2 11:32:09 MET DST 1993 %%%LICENSE_START(GPLv2+_DOC_FULL) This is free documentation; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. The GNU General Public License_zsingle_quotesz_s references to object code and executables are to be interpreted as the output of any document formatting or typesetting system, including intermediate and printed output. This manual is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this manual; if not, see <http://www.gnu.org/licenses/>. %%%LICENSE_END Modified 1993-07-22 by Rik Faith <faithcs.unc.edu> Modified 1993-08-10 by Alan Cox <iiitacpyramid.swansea.ac.uk> Modified 1998-11-04 by Tigran Aivazian <tigransco.com> Modified 2004-05-27, 2004-06-17, 2004-06-23 by Michael Kerrisk |
Section (5) acct
Name
acct — process accounting file
Synopsis
#include <sys/acct.h>
DESCRIPTION
If the kernel is built with the process accounting option
enabled (CONFIG_BSD_PROCESS_ACCT
), then calling
acct(2) starts process
accounting, for example:
acct(/var/log/pacct);
When process accounting is enabled, the kernel writes a
record to the accounting file as each process on the system
terminates. This record contains information about the
terminated process, and is defined in <
sys/acct.h
>
as follows:
#define ACCT_COMM 16 typedef u_int16_t comp_t; struct acct { char ac_flag; /* Accounting flags */ u_int16_t ac_uid; /* Accounting user ID */ u_int16_t ac_gid; /* Accounting group ID */ u_int16_t ac_tty; /* Controlling terminal */ u_int32_t ac_btime; /* Process creation time (seconds since the Epoch) */ comp_t ac_utime; /* User CPU time */ comp_t ac_stime; /* System CPU time */ comp_t ac_etime; /* Elapsed time */ comp_t ac_mem; /* Average memory usage (kB) */ comp_t ac_io; /* Characters transferred (unused) */ comp_t ac_rw; /* Blocks read or written (unused) */ comp_t ac_minflt; /* Minor page faults */ comp_t ac_majflt; /* Major page faults */ comp_t ac_swaps; /* Number of swaps (unused) */ u_int32_t ac_exitcode; /* Process termination status (see wait(2)) */ char ac_comm[ACCT_COMM+1]; /* Command name (basename of last executed command; null-terminated) */ char ac_pad[X
]; /* padding bytes */ }; enum { /* Bits that may be set in ac_flag field */ AFORK = 0x01, /* Has executed fork, but no exec */ ASU = 0x02, /* Used superuser privileges */ ACORE = 0x08, /* Dumped core */ AXSIG = 0x10 /* Killed by a signal */ };
The comp_t
data
type is a floating-point value consisting of a 3-bit, base-8
exponent, and a 13-bit mantissa. A value, c
, of this type can be converted to a (long)
integer as follows:
v = (c & 0x1fff) << (((c >> 13) & 0x7) * 3);
The ac_utime
,
ac_stime
, and
ac_etime
fields
measure time in clock ticks; divide these values by
sysconf(_SC_CLK_TCK)
to
convert them to seconds.
Version 3 accounting file format
Since kernel 2.6.8, an optional alternative version of
the accounting file can be produced if the CONFIG_BSD_PROCESS_ACCT_V3
option is set
when building the kernel. With this option is set, the
records written to the accounting file contain additional
fields, and the width of c_uid
and ac_gid
fields is widened
from 16 to 32 bits (in line with the increased size of UID
and GIDs in Linux 2.4 and later). The records are defined
as follows:
struct acct_v3 { char ac_flag
; /* Flags */char ac_version
; /* Always set to ACCT_VERSION (3) */u_int16_t ac_tty
; /* Controlling terminal */u_int32_t ac_exitcode
; /* Process termination status */u_int32_t ac_uid
; /* Real user ID */u_int32_t ac_gid
; /* Real group ID */u_int32_t ac_pid
; /* Process ID */u_int32_t ac_ppid
; /* Parent process ID */u_int32_t ac_btime
; /* Process creation time */float ac_etime
; /* Elapsed time */comp_t ac_utime
; /* User CPU time */comp_t ac_stime
; /* System time */comp_t ac_mem
; /* Average memory usage (kB) */comp_t ac_io
; /* Characters transferred (unused) */comp_t ac_rw
; /* Blocks read or written
(unused) */comp_t ac_minflt
; /* Minor page faults */comp_t ac_majflt
; /* Major page faults */comp_t ac_swaps
; /* Number of swaps (unused) */char ac_comm
[ACCT_COMM]; /* Command name */};
CONFORMING TO
Process accounting originated on BSD. Although it is present on most systems, it is not standardized, and the details vary somewhat between systems.
NOTES
Records in the accounting file are ordered by termination time of the process.
In kernels up to and including 2.6.9, a separate accounting record is written for each thread created using the NPTL threading library; since Linux 2.6.10, a single accounting record is written for the entire process on termination of the last thread in the process.
The /proc/sys/kernel/acct
file, described in proc(5), defines settings
that control the behavior of process accounting when disk
space runs low.
COLOPHON
This page is part of release 4.16 of the Linux man-pages
project. A
description of the project, information about reporting bugs,
and the latest version of this page, can be found at
https://www.kernel.org/doc/man−pages/.
Copyright (C) 2008, Michael Kerrisk <mtk.manpagesgmail.com> %%%LICENSE_START(VERBATIM) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. %%%LICENSE_END |