PROC(1) User Commands PROC(1)

NAME

proc, pflags, pcred, pldd, psig, pstack, pfiles, pwdx, pstop, prun,
pwait, ptime - proc tools

SYNOPSIS

/usr/bin/pflags [-r] pid | core [/lwp] ...


/usr/bin/pcred [pid | core]...


/usr/bin/pcred [-u user/uid] [-g group/gid] [-G grouplist] pid...


/usr/bin/pcred -l login pid...


/usr/bin/pldd [-Fl] [pid | core]...


/usr/bin/psig [-n] pid...


/usr/bin/pstack [-F] pid | core [/lwp] ...


/usr/bin/pfiles [-Fn] pid | core...


/usr/bin/pwdx pid...


/usr/bin/pstop pid[/lwp] ...


/usr/bin/prun pid[/lwp] ...


/usr/bin/pwait [-v] pid...


/usr/bin/ptime [-Fm] -p pidlist


/usr/bin/ptime [-m] command [arg]...

DESCRIPTION

The proc tools are utilities that exercise features of /proc (see
proc(5)). Most of them take a list of process-ids (pid). The tools that
do take process-ids also accept /proc/nnn as a process-id, so the shell
expansion /proc/* can be used to specify all processes in the system.


Some of the proc tools can also be applied to core files (see core(5)).
The tools that apply to core files accept a list of either process IDs or
names of core files or both.


Some of the proc tools can operate on individual threads. Users can
examine only selected threads by appending /thread-id to the process-id
or core. Multiple threads can be selected using the - and , delimiters.
For example /1,2,7-9 examines threads 1, 2, 7, 8, and 9.


See WARNINGS.

pflags
Print the /proc tracing flags, the pending and held signals,
and other /proc status information for each process or
specified lwps in each process. If an lwp has a non-empty
signal mask, it will be printed.


pcred
Print or set the credentials (effective, real, saved UIDs and
GIDs) of each process.


pldd
List the dynamic libraries linked into each process, including
shared objects explicitly attached using dlopen(3C). See also
ldd(1).


psig
List the signal actions and handlers of each process. See
signal.h(3HEAD). Use pflags to see more information about
currently pending signals and signal masks.


pstack
Print a hex+symbolic stack trace for each process or specified
lwps in each process.


pfiles
Report fstat(2) and fcntl(2) information for all open files in
each process. For network endpoints, the local (and peer if
connected) address information is also provided. For sockets,
the socket type, socket options and send and receive buffer
sizes are also provided. In addition, a path to the file is
reported if the information is available from /proc/pid/path.
This is not necessarily the same name used to open the file.
See proc(5) for more information.


pwdx
Print the current working directory of each process.


pstop
Stop each process or the specified lwps (PR_REQUESTED stop).


prun
Set running each process or the specified lwps (the inverse of
pstop).


pwait
Wait for all of the specified processes to terminate.


ptime
Time the command, like time(1), but using microstate accounting
for reproducible precision. Unlike time(1), children of the
command are not timed.

If the -p pidlist version is used, display a snapshot of timing
statistics for the specified processes. The pidlist may have a
single process or be a comma or space delineated list. If a
space delineated list is used, callers will need to ensure that
it is properly quoted or escaped for their shell.

OPTIONS

The following general options are supported:

-F
Force. Grabs the target process even if another process has
control.


-n
(psig and pfiles only) Sets non-verbose mode. psig displays signal
handler addresses rather than names. pfiles does not display
verbose information for each file descriptor. Instead, pfiles
limits its output to the information that would be retrieved if the
process applied fstat(2) to each of its file descriptors.


-r
(pflags only) If the process is stopped, displays its machine
registers.


-v
(pwait only) Verbose. Reports terminations to standard output.


In addition to the general options, pcred supports the following options:

-g group/gid
Sets the real, effective, and saved group ids (GIDs) of
the target processes to the specified value.


-G grouplist
Sets the supplementary GIDs of the target process to the
specified list of groups. The supplementary groups should
be specified as a comma-separated list of group names
ids. An empty list clears the supplementary group list of
the target processes.


-l login
Sets the real, effective, and saved UIDs of the target
processes to the UID of the specified login. Sets the
real, effective, and saved GIDs of the target processes
to the GID of the specified login. Sets the
supplementary group list to the supplementary groups list
of the specified login.


-u user/uid
Sets the real, effective, and saved user ids (UIDs) of
the target processes to the specified value.


In addition to the general options, pldd supports the following option:

-l
Shows unresolved dynamic linker map names.


In addition to the general options, ptime supports the following options:

-m
Display the full set of microstate accounting statistics.

The displayed fields are as follows:

real
Wall clock time.


user
User level CPU time.


sys
System call CPU time.


trap
Other system trap CPU time.


tflt
Text page fault sleep time.


dflt
Data page fault sleep time.


kflt
Kernel page fault sleep time.


lock
User lock wait sleep time.


slp
All other sleep time.


lat
CPU latency (wait) time.


stop
Stopped time.


-p pid
Displays a snapshot of timing statistics for the specified pid.


To set the credentials of another process, a process must have sufficient
privilege to change its user and group ids to those specified according
to the rules laid out in setuid(2) and it must have sufficient privilege
to control the target process.

USAGE

These proc tools stop their target processes while inspecting them and
reporting the results: pfiles, pldd, and pstack. A process can do nothing
while it is stopped. Thus, for example, if the X server is inspected by
one of these proc tools running in a window under the X server's control,
the whole window system can become deadlocked because the proc tool would
be attempting to print its results to a window that cannot be refreshed.
Logging in from from another system using rlogin(1) and killing the
offending proc tool would clear up the deadlock in this case.


See WARNINGS.


Caution should be exercised when using the -F flag. Imposing two
controlling processes on one victim process can lead to chaos. Safety is
assured only if the primary controlling process, typically a debugger,
has stopped the victim process and the primary controlling process is
doing nothing at the moment of application of the proc tool in question.


Some of the proc tools can also be applied to core files, as shown by the
synopsis above. A core file is a snapshot of a process's state and is
produced by the kernel prior to terminating a process with a signal or by
the gcore(1) utility. Some of the proc tools can need to derive the name
of the executable corresponding to the process which dumped core or the
names of shared libraries associated with the process. These files are
needed, for example, to provide symbol table information for pstack(1).
If the proc tool in question is unable to locate the needed executable or
shared library, some symbol information is unavailable for display.
Similarly, if a core file from one operating system release is examined
on a different operating system release, the run-time link-editor
debugging interface (librtld_db) cannot be able to initialize. In this
case, symbol information for shared libraries is not available.

EXIT STATUS

The following exit values are returned:

0
Successful operation.


non-zero
An error has occurred.

FILES

/proc/*
process files

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | See below. |
+--------------------+-----------------+


The human readable output is Uncommitted. The options are Committed.

SEE ALSO

gcore(1), ldd(1), pargs(1), pauxv(1), penv(1), pgrep(1), pkill(1),
plimit(1), pmap(1), ppgsz(1), preap(1), ps(1), ptree(1), pwd(1),
rlogin(1), time(1), truss(1), wait(1), fcntl(2), fstat(2), setuid(2),
dlopen(3C), signal.h(3HEAD), core(5), proc(5), process(5), attributes(7),
zones(7)

WARNINGS

The following proc tools stop their target processes while inspecting
them and reporting the results: pfiles, pldd, and pstack. However, even
if pstack operates on an individual thread, it stops the whole process.


A process or thread can do nothing while it is stopped. Stopping a
heavily used process or thread in a production environment, even for a
short amount of time, can cause severe bottlenecks and even hangs of
these processes or threads, causing them to be unavailable to users. Some
databases could also terminate abnormally. Thus, for example, a database
server under heavy load could hang when one of the database processes or
threads is traced using the above mentioned proc tools. Because of this,
stopping a UNIX process or thread in a production environment should be
avoided.


A process or thread being stopped by these tools can be identified by
issuing /usr/bin/ps -eflL and looking for "T" in the first column.
Notice that certain processes, for example "sched", can show the "T"
status by default most of the time.


The process ID returned for locked files on network file systems might
not be meaningful.

June 15, 2016 PROC(1)