The loop around ttyname_r() makes it look like we use unbounded stack
allocations. We know that that paths have a maximum size, so let's simplify
the whole thing.
Replaces #12043.
Let's make sure the integers we parse out are not larger than USHRT_MAX.
This is a good idea as the kernel's TIOCSWINSZ ioctl for sizing
terminals can't take larger values, and we shouldn't risk an overflow.
This is a bit like the info link in most of GNU's --help texts, but we
don't do info but man pages, and we make them properly clickable on
terminal supporting that, because awesome.
I think it's generally advisable to link up our (brief) --help texts and
our (more comprehensive) man pages a bit, so this should be an easy and
straight-forward way to do it.
These lines are generally out-of-date, incomplete and unnecessary.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.
If the main config file or one of the drop-ins did not have the final newline,
there would be no seperating empty line (or if this was the last file
displayed, our own output would end without the final newline, possibly running
into the subsequent prompt or such). copy_bytes() does not know anything about
lines, so let's just use a normal loop with read_line() and puts().
This is used as 'systemd-analyze show-config systemd/logind.conf', which
will dump
/etc/systemd/system/user@.service
/etc/systemd/system/user@.service.d/*.conf
/run/systemd/system/user@.service.d/*.conf
/usr/local/lib/systemd/system/user@.service.d/*.conf
/usr/lib/systemd/system/user@.service.d/*.conf
The idea is to make it easy to dump the configuration using the same locations
and order that systemd programs use themselves (including masking, in the right
order, etc.). This is the generic variant that works with any configuration
scheme that follows the same general rules:
$ systemd-analyze cat-config systemd/system.conf
$ systemd-analyze cat-config systemd/user.conf
$ systemd-analyze cat-config systemd/logind.conf
$ systemd-analyze cat-config systemd/sleep.conf
$ systemd-analyze cat-config systemd/journald.conf
$ systemd-analyze cat-config systemd/journal-remote.conf
$ systemd-analyze cat-config systemd/journal-upload.conf
$ systemd-analyze cat-config systemd/coredump.conf
$ systemd-analyze cat-config systemd/resolved.conf
$ systemd-analyze cat-config systemd/timesyncd.conf
$ systemd-analyze cat-config udev/udev.conf
Newer terminals (in particular gnome-terminal) understand special escape
sequence for formatting clickable links. Let's support that to make our
tool output more clickable where that's appropriate.
For details see this:
https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda
The one big issue is that 'less' currently doesn't grok this, and
doesn't ignore sequence like regular terminal implementations do if they
don't support it. Hence for now, let's disable URL output if a pager is
used. We should revisit that though as soon as less added support for it
and enough time passed for it to enter various distributions.
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.
This is similar to TAKE_PTR() but operates on file descriptors, and thus
assigns -1 to the fd parameter after returning it.
Removes 60 lines from our codebase. Pretty good too I think.
This macro will read a pointer of any type, return it, and set the
pointer to NULL. This is useful as an explicit concept of passing
ownership of a memory area between pointers.
This takes inspiration from Rust:
https://doc.rust-lang.org/std/option/enum.Option.html#method.take
and was suggested by Alan Jenkins (@sourcejedi).
It drops ~160 lines of code from our codebase, which makes me like it.
Also, I think it clarifies passing of ownership, and thus helps
readability a bit (at least for the initiated who know the new macro)
At various places we only want to close fds if they are not
stdin/stdout/stderr, i.e. fds 0, 1, 2. Let's add a unified helper call
for that, and port everything over.
Let's forget all relevant terminal features we learnt when we make a
console or /dev/null stdin/stdout/stderr.
Also, while we are at it, let's drop the various _unlikely_ and
_likely_ annotiations around the terminal feature caches. In many cases
we call the relevant functions only once in which cases the annotations
are likely to do just harm and no good. After all we can't know if the
specific code will call us just once or many times...
This modernizes acquire_terminal() in a couple of ways:
1. The three boolean arguments are replaced by a flags parameter, that
should be more descriptive in what it does.
2. We now properly handle inotify queue overruns
3. We use _cleanup_ for closing the fds now, to shorten the code quite a
bit.
Behaviour should not be altered by this.
Using wait_for_terminate_and_check() instead of wait_for_terminate()
let's us simplify, shorten and unify the return value checking and
logging of waitid(). Hence, let's use it all over the place.
This adds a new safe_fork() wrapper around fork() and makes use of it
everywhere. The new wrapper does a couple of things we previously did
manually and separately in a safer, more correct and automatic way:
1. Optionally resets signal handlers/mask in the child
2. Sets a name on all processes we fork off right after forking off (and
the patch assigns useful names for all processes we fork off now,
following a systematic naming scheme: always enclosed in () – in order
to indicate that these are not proper, exec()ed processes, but only
forked off children, and if the process is long-running with only our
own code, without execve()'ing something else, it gets am "sd-" prefix.)
3. Optionally closes all file descriptors in the child
4. Optionally sets a PR_SET_DEATHSIG to SIGTERM in the child, in a safe
way so that the parent dying before this happens being handled
safely.
5. Optionally reopens the logs
6. Optionally connects stdin/stdout/stderr to /dev/null
7. Debug logs about the forked off processes.
Ultimately, O_CLOEXEC should be off in fd 0, 1, 2, but when we open
/dev/null here it's unlikely to be < 0, and after dupping the fd to 0,
1, 2 we turn off O_CLOEXEC explicitly anyway.
Unless we know that what we are about to open will return 0, 1 or 2 we
should always set O_CLOEXEC in order to be safe to other threads forking
of subprocesses at the wrong moment.
Just a minor tweak, making sure we execute as much as we can of the
funciton, but return the first error instead of the last we encounter.
This is usuelly how we do things when we have functions that continue on
the first error, so let's do it like that here too.
