proc, pflags, pcred, pldd, psig, pstack, pfiles, pwdx, pstop, prun, pwait, ptime
- proc tools
/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]...
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.
-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.
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.
The following exit values are returned:
0
Successful operation.
non-zero
An error has occurred.
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.
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)
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.