If you have the watched program doing some other thing every time its
run and you resize the window, you might get unexpected results. The
-r option lets you run only when the interval has expired.
References:
procps-ng/procps!125procps-ng/procps#190
In production we've had several incidents over the years where a process
has a signal handler registered for SIGHUP or one of the SIGUSR signals
which can be used to signal a request to reload configs, rotate log
files, and the like. While this may seem harmless enough, what we've
seen happen repeatedly is something like the following:
1. A process is using SIGHUP/SIGUSR[12] to request some
application-handled state change -- reloading configs, rotating a log
file, etc;
2. This kind of request is deprecated and removed, so the signal handler
is removed. However, a site where the signal might be sent from is
missed (often logrotate or a service manager);
3. Because the default disposition of these signals is terminal, sooner
or later these applications are going to be sent SIGHUP or similar
and end up unexpectedly killed.
I know for a fact that we're not the only organisation experiencing
this: in general, signal use is pretty tricky to reason about and safely
remove because of the fairly aggressive SIG_DFL behaviour for some
common signals, especially for SIGHUP which has a particularly ambiguous
meaning. Especially in a large, highly interconnected codebase,
reasoning about signal interactions between system configuration and
applications can be highly complex, and it's inevitable that on occasion
a callsite will be missed.
In some cases the right call to avoid this will be to migrate services
towards other forms of IPC for this purpose, but inevitably there will
be some services which must continue using signals, so we need a safe
way to support them.
This patch adds support for the -H/--require-handler flag, which matches
on processes with a userspace handler present for the signal being sent.
With this flag we can enforce that all SIGHUP reload cases and SIGUSR
equivalents use --require-handler. This effectively mitigates the case
we've seen time and time again where SIGHUP is used to rotate log files
or reload configs, but the sending site is mistakenly left present after
the removal of signal handler, resulting in unintended termination of
the process.
Signed-off-by: Chris Down <chris@chrisdown.name>
When the p/e-cores support (via the '5' key) was added
in the patch referenced below, I intentionally omitted
that key from the top primary help screen. This seemed
appropriate since it only applied to select Intel cpus
and, besides, that screen was getting kind of crowded.
[ it remains an objective to fit on a 80x24 terminal ]
Upon reflection, I found a way to squeeze it into that
help screen and have decided to included it. Hopefully
its presence will encourage use of top's new provision
on any Intel platforms that distinguish between cores.
Reference(s):
Sep, 2022 - exploit p/e-cores provision
commit 00f5c74b1b
Signed-off-by: Jim Warner <james.warner@comcast.net>
In the commits referenced below special code was added
to make the bottom window sticky and fix the bug after
'Cap_nl_clreos' was traded for the 'Cap_clr_eol' loop.
However, there's always major overhead associated with
interacting with a terminal. So we'll only abandon the
single 'Cap_nl_clreos' putp in favor of repeated calls
with 'Cap_clr_eol' when a bottom window isn't present.
Reference(s):
. May, 2022 - bottom window batch bug fix
commit 793f3e85ae
. May, 2022 - bottom window made sticky
commit 0f2a755b0b
Signed-off-by: Jim Warner <james.warner@comcast.net>
Please, do not look at the actual changes made by this
commit. Trust me they will vastly improve performance.
Signed-off-by: Jim Warner <james.warner@comcast.net>
vmstat <n> would update most fields, but the memory statistics
were only fetched the first time.
References:
https://bugs.debian.org/1027963
Signed-off-by: Craig Small <csmall@dropbear.xyz>
procps 3.3.17 the c option changed the command/args field
to cmd but this got removed as part of newlib
Functionality is back in with a test case.
References:
https://bugs.debian.org/1026326
Signed-off-by: Craig Small <csmall@dropbear.xyz>
When the skill program was ported to the new API the code to filter
on PID, used by the -p option, was missed. It is now restored.
References:
https://bugs.debian.org/1025915
Commit c8384e682c ("pgrep: add pwait") changed from the old i_am_pkill
logic, but mistakenly missed a break in the pkill case. This results in
showing -e/--echo twice when running `pkill -h'.
Signed-off-by: Chris Down <chris@chrisdown.name>
Replace AC_CHECK_FUNC by AC_CHECK_FUNCS otherwise HAVE_PIDFD_OPEN will
never be defined resulting in the following build failure if pidfd_open
is available but __NR_pidfd_open is not available:
pgrep.c: In function 'pidfd_open':
pgrep.c:748:17: error: '__NR_pidfd_open' undeclared (first use in this function); did you mean 'pidfd_open'?
748 | return syscall(__NR_pidfd_open, pid, flags);
| ^~~~~~~~~~~~~~~
| pidfd_open
This build failure is raised since the addition of pwait in version
3.3.17 and
c8384e682c
Fixes:
- http://autobuild.buildroot.org/results/f23a5156e641b2ebdd673973dec0f9c87760c688
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Thanks to @kabe-gl for this patch.
w command shows ????? for LOGIN@ column when compiled on 32bit environment with -D_TIME_BITS=64.
References:
#256
Signed-off-by: Craig Small <csmall@dropbear.xyz>
Just as our library was made responsive to a potential
missing 'core id', the top program should also change.
That's because he has his own PRETENDECORE #define and
if that was activated on a platform without 'core id',
the 'CpP' notations would have otherwise been omitted.
Reference(s):
. Oct, 2022 - library fix for missing 'core id'
commit b89e3230b2
Signed-off-by: Jim Warner <james.warner@comcast.net>
When support for graphs was refactored, in that commit
referenced below, the logic for our 'MEMGRAPH_OLD' was
lost while the #define itself remained in the .h file.
Faced with deleting the #define or restoring the logic
I chose the latter. Thus, if one wanted to be reminded
how overstated 'used' memory once was, it can be done.
Reference(s):
. Sep, 2022 - refactored graph support
commit 2d5b51d1a2
Signed-off-by: Jim Warner <james.warner@comcast.net>
When long command line options were introduced, in the
patch shown below, the string associated with the enum
'WRONG_switch_fmt' became obsolete. However, that enum
and its string were never removed. Well, now they are.
Reference(s):
. Sep, 2021 - getopt and long cmdline options
commit c91b371485
Signed-off-by: Jim Warner <james.warner@comcast.net>
In that commit referenced below, I removed the command
line help text from any translation so the TP wouldn't
delay our 4.0.1 release any further. In looking to the
future, when we might be able to reverse that, I found
gettext tools blocking use of the compile conditional.
They are too primitive for the original approach so we
must modify that exclusion mechanism hack accordingly.
____________________________excerpted program comments
The provision excluding some strings is intended to be
used very sparingly. It exists in case we collide with
some translation project person in a position to delay
a future release over his or her personal preferences.
If it's ever enabled, it will produce a fatal compiler
error as our only option since those gettext tools are
far too primitive to be influenced with a conditional.
They always ignore a '_X()' macro no matter its state.
Reference(s):
commit 8a368bfb05
Signed-off-by: Jim Warner <james.warner@comcast.net>
The provision excluding some strings is intended to be
used very sparingly. It exists in case we collide with
some translation project person in a position to delay
a future release over his or her personal preferences.
(it's currently used only on v4.0.1 command line help)
Signed-off-by: Jim Warner <james.warner@comcast.net>
Prior to this commit, when the '5' key was struck, top
would check for the presence of e-cores just one time.
That meant if a some cpu was brought online, and it in
turn exposed a new e-core after top has started, users
needed a top restart to activate the new '5' feature.
So, now we'll check for any e-cores with each '5' key.
Signed-off-by: Jim Warner <james.warner@comcast.net>
I sure hope we won't disappoint the library with these
changes since we're only exploiting one of the two new
enumerators that the immediately prior patch provided.
Now top will be able to offer a visual clue as to each
cpu (thread actually) core association. Is it a P-core
offering multiple threads or a single threaded E-core.
We'll accomplish this feat with a subtle change to the
states portion ('t' toggle) of the summary area. Where
before processors were represented as 'Cpu', they will
now be displayed as 'CpP' (P-core) and 'CpE' (E-core).
[ assuming that new '5' command toggle has been used ]
There are also new provisions for filtering those cpus
by their core type association via the new '5' toggle.
Signed-off-by: Jim Warner <james.warner@comcast.net>
When that 'Bottom' window was being finalized, an enum
of BREAK_screen was added to the Frames_signal values.
This was done so some full screen replacement function
could flag the need for that bottom window to go away.
Around that same time, top was made more responsive to
keyboard input so that residual portions of a previous
bottom window would not linger until the next refresh.
This happened if going from a larger (^N, environment)
bottom window to some smaller window (^P, namespaces).
The combined effect of these changes was to create the
potential race condition this commit addresses. If the
user encountered a SIGWINCH while on any of those full
screen replacement displays (help, fields mgmt, etc.),
endless redraws would occur. A ^C was the only option.
Henceforth we will protect against any redraw loops by
clearing Frames_signal each time a redraw is required.
[ along the way, we'll make the 'q' key work on that ]
t secondary 'windows' help screen as it should, even ]
[ though it is not documented on that screen itself. ]
Reference(s):
. May, 2022 - more responsive to keyboard input
commit 3ea1bc779f
. May, 2022 - maybe force the bottom window off
commit d66c1f39b5
Signed-off-by: Jim Warner <james.warner@comcast.net>
Darn, after testing on some older, out of date distros
I was embarrassed to find some awful code I created in
the commit shown below. I was rewarded with some 'nan'
floating point values and 'inf' computational results.
Reference(s);
. a missed opportunity to repent
commit 5c5bff392b
. true source of my original sin
commit 2d5b51d1a2
Signed-off-by: Jim Warner <james.warner@comcast.net>
If one per line display of Mem/Swap data was forced by
this #define, screen width was not fully exploited for
graph mode. Rather, those graphs were scaled just like
they would be if aligned with a nonexistent separator.
With this commit, those graphs will expand to fill the
screen width (or be limited by the maximum of '100' ).
[ and in unrelated news a variable used in do_memory ]
[ was changed for consistency. it doesn't affect the ]
[ the results since a part1 of swap was always zero. ]
Signed-off-by: Jim Warner <james.warner@comcast.net>
This patch introduces a new #define TOG4_MEM_FIX which
serves to turn off the new feature it also implements.
The feature, on by default, provides a flexible memory
graph approach which strives to always keep its visual
separator in alignment with cpu separators seen above.
Below is a summary of the algorithm implementing this:
1) First, ascertain the widest graph which corresponds
to the largest number of cpu graphs but doesn't exceed
maximum allowable graph width (i.e. GRAPH_length_max).
2) Next, apply that to the graphed 'Mem' portion which
is likely to remain entirely visible. However, it will
grow or shrink depending on total adjacent cpu graphs.
3) Last, the same width is used for the 'Swap' portion
but that graph is considered sacrificial and very well
could be truncated depending on the width of a screen.
[ along the way, when the cpu graphs revert to their ]
[ abbreviated form, the memory graphs will also show ]
[ an abbreviated prefix. in this way the widths will ]
[ also be maximized, reducing potential distortions. ]
Signed-off-by: Jim Warner <james.warner@comcast.net>
This commit will change some comments, adjust a little
whitespace but mostly rename some #define identifiers.
Signed-off-by: Jim Warner <james.warner@comcast.net>
When displaying detailed memory statistics two abreast
data for the lines are less than those for cpus. So we
can exploit such a difference to provide a distinctive
separator. This may help separating cpu & memory data.
[ in truth, this happened before this patch. what we ]
[ are doing now is polishing that accidental feature ]
[ and placing it under the control of a conditional. ]
Signed-off-by: Jim Warner <james.warner@comcast.net>
When displaying detailed cpu statistics, as opposed to
those scalable graphs, only two per line can be shown.
Therefore, if we are showing a detail version, our '4'
toggle must prematurely revert to single mode display.
Conversely, the 't' toggle must also turn off that '4'
toggle rather than try to print more than 2 abreast if
we're currently executing in detailed statistics mode.
Signed-off-by: Jim Warner <james.warner@comcast.net>
When more than two cpus are displayed per summary area
line in graph form, those memory graphs were scaled to
that same width for consistency & aesthetics. However,
they probably shouldn't have been reduced to less than
terminal width due to a resulting loss of information.
[ after all, detailed memory stats are never reduced ]
So now, supporting logic was refactored to behave just
as it did before the 4 toggle was expanded beyond '1'.
[ the changes impact the 2 memory graphs exclusively ]
Reference(s):
https://www.freelists.org/post/procps/top-enhancements-2-bugs-swatted,1
Signed-off-by: Jim Warner <james.warner@comcast.net>
This patch just supplements the previous series with a
few minor tweaks representing some diverse objectives:
. a recent date for man page (which i always overlook)
. improved length calculations to maximize graph width
. a proper response to platforms with less than 8 cpus
. more consistency and readability with one blank line
Signed-off-by: Jim Warner <james.warner@comcast.net>
Well, here it is. This is what the preceding series of
commits was leading to: an ability to show up to eight
cpus per Summary Area line. In reality, a self imposed
limit of four cpus on such lines seems more realistic.
In any case, the new capability could also be employed
along with that '!' toggle which consolidates adjacent
cpus into a solitary graph. When used together the '4'
and '!' toggles should accommodate any number of cpus.
Signed-off-by: Jim Warner <james.warner@comcast.net>
I guess the cat's out of the bag with the prior commit
message. It mentioned the objective of displaying more
than the current two cpu graphs on summary area lines.
On the way to that objective, this patch just prepares
our battlefield for the actual implementation in which
up to 8 individual cpu graphs will be shown on 1 line.
[ no logic has been impacted with this commit. we're ]
[ just adding one manifest constant, trading several ]
[ identifiers and updating some comments so the next ]
[ commit might be just a little bit more manageable. ]
Signed-off-by: Jim Warner <james.warner@comcast.net>
This program has always been sensitive to the width of
a terminal/console. The detailed cpu/memory statistics
plus all of those full screen replacement windows were
designed to fit within some 80 column, 24 row display.
When a user narrowed a gui terminal to less than those
dimensions, top would simply truncate the data to fit.
However, when displaying cpu/mem graphs instead of the
detailed statistics such truncation was not justified.
After all, such graphs were already scaled to 80 cols.
Henceforth, when in graph mode, truncation won't occur
until the graphs will no longer fit within 10 columns.
[ can you keep a secret? this change is really being ]
[ made in anticipation of showing more than just two ]
[ cpu graphs in the summary area on each screen row! ]
Signed-off-by: Jim Warner <james.warner@comcast.net>
The logic (illogic?) in the sum_tics() and do_memory()
functions has grown to become almost unfathomable over
time. Additionally, though perhaps not apparent in the
code, many steps are duplicated within those routines.
So, this patch refactors all the summary graph support
to consolidate duplicated code and (hopefully) make it
more understandable with an eye to future maintenance.
[ additionally, that show_special guy's workload has ]
[ been reduced by eliminating any special directives ]
[ previously embedded in some cpu graphs even though ]
[ a cpu may have been idle during the last interval. ]
Signed-off-by: Jim Warner <james.warner@comcast.net>
When 2 abreast cpu display was introduced, the minimum
screen width was 160 columns so as to avoid (minimize)
truncation. Later that was reduced to 80 columns while
keeping the original minimum as a compile conditional.
In preparation for (virtually) eliminating these width
restrictions in a future patch this #define's history.
Reference(s):
. May, 2020 - introduced #define TOG4_NOTRUNC
commit be3dcaa842
. May, 2020 - introduce 2 abreast display
commit 59f5a37a24
Signed-off-by: Jim Warner <james.warner@comcast.net>
When two abreast display was introduce, in that commit
shown below, this #define provision was also added. It
actually was an artifact left from program development
and never made much sense in a real world application.
If activated it would make the '4' toggle appear to be
broken since it would only take affect if a user first
activated individual cpu display (the '1' toggle off).
And there was no error message offered to those users.
So, this questionable #define is now being eliminated.
Reference(s):
. May, 2020 - introduce 2 abreast display
commit 59f5a37a24
Signed-off-by: Jim Warner <james.warner@comcast.net>
When top was made more responsive to keyboard input in
that commit referenced below, his previous response to
a SIGWINCH was upset. Formerly, that display integrity
was restored with the next refresh cycle. But, without
this patch, one must strike some key to accomplish it.
[ in truth, this patch vastly improves that sigwinch ]
[ response. whereas before, although integrity would ]
[ be restored automatically, it did not happen until ]
[ the next regular refresh. now it is instantaneous! ]
Reference(s):
. May, 2022 - made more responsive to kdb input
commit 3ea1bc779f
Signed-off-by: Jim Warner <james.warner@comcast.net>
Turn on trace() with the TRACE macro and remove the ## token paste
preprocessor operator which is unnecessary here and causes these errors:
ps/common.h:176:26: error: pasting "(" and ""ps_argv[thisarg] is %s\n""
does no t give a valid preprocessing token
.
Send trace output to STDERR.
Tracing can be enabled by adding TRACE to CPPFLAGS as follows:
./configure CPPFLAGS="-DTRACE"
Signed-off-by: Rafael Kitover <rkitover@gmail.com>
pgrep and friends naturally filter their own processes from their
matches. The same issue can occur when elevating with tools like sudo or
doas, where the elevating shim layers linger as a parent and are
returned in the results. For example:
% sudo pkill -9 -cf someelevatedcmdline
1
zsh: killed sudo pkill -9 -cf someelevatedcmdline
This is a situation we've actually seen in production, where some poor
soul changes how permission management works (for example with Linux's
hidepid option), needs to elevate a pgrep or pkill call, and now ends up
with more than they bargained for. Even after the issue is noticed,
resolving it requires reinventing some of the pgrep logic, which is
unfortunate.
This commit adds the -A/--ignore-ancestors option which excludes pgrep's
ancestors from the results:
% sudo ./pkill -9 -Acf someelevatedcmdline
0
We looks at multiple layers of the process hierarchy because, while
things like sudo only have one layer of shimming, some mechanisms (like
those found in a typical container manager like those found in Docker or
Kubernetes) may have many more.
Signed-off-by: Chris Down <chris@chrisdown.name>
