CHECKPROC(8)

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 specification). 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.

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.

-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 filename 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)).

SEE ALSO
startproc(8), killproc(8), insserv(8), init.d(7), kill(1), skill(1), killall(8), killall5(8), signal(7), proc(5).

COPYRIGHT
1994-2000 Werner Fink, 1996-2000 SuSE GmbH Nuernberg, Germany.

AUTHOR
Werner Fink <werner@suse.de>