From Linux Man Pages
NAME
Checkproc - Checks for a process by full path name
Pidofproc - Checks for a process by exec base name
SYNOPSIS
checkproc [-v] [-L] [-k] [-p pid_file] [-i ingnore_file] [-c root] [-z] /full/path/to/executable
checkproc [-v] [-k] [-n] name_of_kernel_thread
pidofproc [-k] basename_of_executable
DESCRIPTION
checkproc checks for running processes that use the specified executable.
checkproc does not use the pid to verify a process but the full path of the corresponding program which is used
to identify the executable (see proc(5)). Only if the inode number (/proc/<pid>/exe) and the full name are
unavailable (/proc/<pid>/cmdline) or if the executable changes its zeroth argument, checkproc uses the base name
(/proc/<pid>/stat) to identify the running program. Note that if the option -n for kernel thread is given only
(/proc/<pid>/stat) is used. For this case a existing symbolic link (/proc/<pid>/exe) indicates that the <pid> is
not a kernel thread.
Extended functionality is provided by the -p pid_file option (former option -f changed due to the LSB specifica-
tion). If this option is specified, checkproc tries to check the pid read from this file instead of the default
(/var/run/<basename>.pid). The pid read from this file is compared against the pids of the processes that uses
the specified binary. If the option -k is specified, checkproc works like killproc that is that if the if the
pid_file does not exist, checkproc assumes that the daemon is not running. It is possible to use a process iden-
tity number instead of a pid file.
For the possibility of having two different sessions of one binary program, the option -i ignore_file allows to
specify a pid file which pid number is used to ignore all processes of corresponding process session.
Note that the behaviour above is changed by the option -k. With this option, the pid read from the pid file is
the only used pid (see killproc(8)) and with this option also exit codes like startproc(8) or killproc(8) are
used. Without this option, the pid read from the pid file is used to search the process table for a process with
an executable that matches the specified pathname. In order to avoid confusion with stale pid files, a not up-to-
date pid will be ignored (see startproc(8)).
The option -v makes checkproc print out verbose messages. The same happens if pidofproc LSB variant is used.
This version also accepts also the base name only of a executable. Note that this disables the comparision of
the inodes of the executable and the information found within the proc table (see proc(5)).
REQUIRED
/full/path/to/executable or name_of_kernel_thread
Specifies the executable which processes should be found, or alternatively, if the option Or alternated,
if option -n is used, the name of the kernel thread. This argument is always required.
OPTIONS
-k This option makes checkproc work like killproc(8) which changes the operation mode, e.g. the exit status
of the program will be that of killproc(8) and startproc(8). Without this option, checkproc works like
startproc (8) and finds all processes with an executable that matches the specified pathname, even if a
given pid file (see option -p) isn't up-to-date. Nevertheless it uses its own exit status (see section
EXIT CODES).
-L This option causes symlinks to be followed, as the like-named option in ls(1). Note: for the file name
the original name of the program is used instead of the name of the symbolic link.
-p pid_file
Former option -f changed due to the LSB specification.) Use an alternate pid file instead of the default
/var/run/<basename>.pid. If the option is specified and the pid_file does not exist, checkproc assumes
that the daemon is not running. It is possible to use a process identity number instead of a pid file.
-i ignore_file
The pid found in this file is used as session id of the same binary program which should be ignored by
checkproc.
-c root
Change root directory to root for services which have been started with this option by startproc(8).
-n This option indicates that a kernel thread should be checked. In this case not the executable with its
full path name is required but the name of the kernel thread.
-q This option is ignored.
-v Verbose output.
-z This option causes checkproc to see processes even if they are in the zombie state. Without this option
zombies are handled as not existent because such a process isn't alive but listed in the process table and
waits on its parent process.
EXAMPLE
checkproc /usr/sbin/sendmail
returns all pids of running sendmail processes.
checkproc -p /var/myrun/lpd.pid /usr/sbin/lpd
returns the command line or the basename of the process pid found in /var/run/lpd.pid.
EXIT CODES
The exit codes without the option -k have the following LSB conform conditions:
0 Program is running
1 No process but pid file found
3 No process and no pid file found
101 Wrong syntax on command line
102 Other errors
If the option -k is used checkproc uses exit codes like startproc(8) or killproc(8) do:
0 Program is running
1 Generic or unspecified error
2 Invalid or excess argument(s)
4 Insufficient privilege(s)
5 Program is not installed
7 Program is not running
in some cases a message is send to standard error or, if no standard error available, syslogd(8) is used.
NOTE
checkproc together with the option -v just like pidof(8). The only difference is the usage of an available pid
file. Only if no usable pid is given with a pid file the process table will be scanned.
BUGS
Identifying a process based on the executable file and the corresponding inode number only works if the process
stays alive during startproc's execution. Processes rewriting their zeroth argument or shell scripts (the inode
number of the shell executable file is not identical to that of the script file) may not be identified by a file-
name path.
FILES
/proc/ path to the proc file system (see proc(5)).
/etc/init.d/
path to the SuSE boot concept script base directory as required by the Linux Standard Base Specification
(LSB) (see init.d(7)).
RELATED
startproc(8), killproc(8), insserv(8), init.d(7), kill(1), skill(1), killall(8), killall5(8), signal(7), proc(5).
COPYRIGHT
1994-2005 Werner Fink, 1996-2005 SuSE GmbH Nuernberg, Germany.
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