This is a lot of stuff, and sometimes quite wild, let's turn this into
its own header.
All stuff color-related that just generates sequences is now in
ansi-color.h (no .c file!), and everything more complex that
probes/ineracts with terminals remains in termina-util.[ch]
This restores display of the "delegate" flag of a cgroup. Previously we
erroneously passed a full fs path where a cgroup path was expected (the
difference being the /sys/fs/cgroup/ prefix), which meant we never read
the xattr properly. Let's fix that by simply operating by fd on the
cgroup and using it for all operations.
In various tools and services we have a per-system and per-user concept.
So far we sometimes used a boolean indicating whether we are in system
mode, or a reversed boolean indicating whether we are in user mode, or
the LookupScope enum used by the lookup path logic.
Let's address that, in introduce a common enum for this, we can use all
across the board.
This is mostly just search/replace, no actual code changes.
-1 was used everywhere, but -EBADF or -EBADFD started being used in various
places. Let's make things consistent in the new style.
Note that there are two candidates:
EBADF 9 Bad file descriptor
EBADFD 77 File descriptor in bad state
Since we're initializating the fd, we're just assigning a value that means
"no fd yet", so it's just a bad file descriptor, and the first errno fits
better. If instead we had a valid file descriptor that became invalid because
of some operation or state change, the other errno would fit better.
In some places, initialization is dropped if unnecessary.
So far we set the "trusted.delegate" xattr on cgroups where delegation
is on. This duplicates this behaviour with the "user.delegate" xattr.
This has two benefits:
1. unprivileged clients can *read* the xattr. "systemd-cgls" can thus
show delegated cgroups as such properly, even when invoked without
privs
2. unprivileged systemd instances can set the xattr, i.e. when systemd
--user delegates a cgroup to further payloads.
This weakens security a tiny bit, given that code that got a cgroup
delegated can manipulate the xattr, but I think that's OK, given they
have a higher trust level regarding cgroups anyway, if they got a
subtree delegated, and access controls on the cgroup itself are still
enforced. Moreover PID 1 as the cgroup manager only sets these xattrs,
never reads them — the xattr is primarily a way to tell payloads about
the delegation, and it's strictly this one way.
(Or when -H is used, since -H and -M are incompatible.)
Note that the slightly unusual form with separate boolean variables (hint_vars,
hint_addr) instead of e.g. a const char* variable to hold the message, because this
way we don't trigger the warning about non-literal format.
let's make sure the specified hostname is really valid before we build
an fs path from it. Just as a safety future, so that people can't trick
us with hostnames including "/../" or so.
Unfortunately fgetxattr() and flistxattr() don't work via O_PATH fds.
Let's thus add fallbacks to go via /proc/self/fd/ in these cases.
Also, let's merge all the various flavours we have here into singular
implementations that can do everything we need:
1. malloc() loop handling
2. by fd, by path, or combination (i.e. a proper openat() like API)
3. work on O_PATH
We recently started making more use of malloc_usable_size() and rely on
it (see the string_erase() story). Given that we don't really support
sytems where malloc_usable_size() cannot be trusted beyond statistics
anyway, let's go fully in and rework GREEDY_REALLOC() on top of it:
instead of passing around and maintaining the currenly allocated size
everywhere, let's just derive it automatically from
malloc_usable_size().
I am mostly after this for the simplicity this brings. It also brings
minor efficiency improvements I guess, but things become so much nicer
to look at if we can avoid these allocation size variables everywhere.
Note that the malloc_usable_size() man page says relying on it wasn't
"good programming practice", but I think it does this for reasons that
don't apply here: the greedy realloc logic specifically doesn't rely on
the returned extra size, beyond the fact that it is equal or larger than
what was requested.
(This commit was supposed to be a quick patch btw, but apparently we use
the greedy realloc stuff quite a bit across the codebase, so this ends
up touching *a*lot* of code.)
This should help visualize where one manager's territory begins and
another's starts. Do this by underlining (since it's a "cut" point an
underline made most sense to me). Since underlining is not visible on
the console let's also show an ellipses for all lines that are
delegation boundaries.
Unfortunately this all is not as useful as it appears. The
"trusted.delegate" xattr is only visible to roo, which means
"systemd-cgls" has be called as root to show the boundaries.
Unfortunately cgroupfs doesn't support unprivileged xattrs on cgroups.
This restores show_pid_array() output in legacy locales on the console.
Only one call to get_process_cmdline() is changed, all others retain
utf8-only mode. This affects systemd-cgls, systemctl status, etc, when
working locally.
Calls to get_process_cmdline() that cross a process boundary always use
utf8. It's the callers responsibility to convert this to some encoding that
they use. This means that we always pass utf8 over the bus.
The functions to retrieve and print process cmdlines were based on the
assumption that they contain printable ASCII, and everything else
should be filtered out. That assumption doesn't hold in today's world,
where people are free to use unicode everywhere.
This replaces the custom cmdline reading code with a more generic approach
using utf8_escape_non_printable_full().
For kernel threads, truncation is done on the parenthesized name, so we'll
get "[worker]", "[worker…]", …, "[w…]", "[…", "…" as we reduce the number of
available columns.
This implementation is most likely slower for very long cmdlines, but I don't
think this is very important. The common case is to have short commandlines,
and should print those properly. Absurdly long cmdlines are the exception,
which needs to be handled correctly and safely, but speed is not too important.
Fixes#12532.
v2:
- use size_t for the number of columns. This change propagates into various
other functions that call get_process_cmdline(), increasing the size of the
patch, but the changes are rather trivial.
This has been irritating me for quite a while: let's prefix these enum
values with a common prefix, like we do for almost all other enums.
No change in behaviour, just some renaming.
Now that we don't (mis-)use the env file parser to parse kernel command
lines there's no need anymore to override the used newline character
set. Let's hence drop the argument and just "\n\r" always. This nicely
simplifies our code.
These lines are generally out-of-date, incomplete and unnecessary. With
SPDX and git repository much more accurate and fine grained information
about licensing and authorship is available, hence let's drop the
per-file copyright notice. Of course, removing copyright lines of others
is problematic, hence this commit only removes my own lines and leaves
all others untouched. It might be nicer if sooner or later those could
go away too, making git the only and accurate source of authorship
information.
This part of the copyright blurb stems from the GPL use recommendations:
https://www.gnu.org/licenses/gpl-howto.en.html
The concept appears to originate in times where version control was per
file, instead of per tree, and was a way to glue the files together.
Ultimately, we nowadays don't live in that world anymore, and this
information is entirely useless anyway, as people are very welcome to
copy these files into any projects they like, and they shouldn't have to
change bits that are part of our copyright header for that.
hence, let's just get rid of this old cruft, and shorten our codebase a
bit.
Most our other parsing functions do this, let's do this here too,
internally we accept that anyway. Also, the closely related
load_env_file() and load_env_file_pairs() also do this, so let's be
systematic.
Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.
I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
Daan De Meyer
Lennart Poettering
Timo Rothenpieler
David Tardon
Nick Rosbrook
Zbigniew Jędrzejewski-Szmek
Jan Janssen
nl6720
Yu Watanabe
fangxiuning