CLONE_PIDFD was introduced in v5.2 and in sched.h in glibc-2.31 so
without this, building with older version fails with:
src/basic/raw-clone.h:41:108: error: 'CLONE_PIDFD' undeclared (first use in this function); did you mean 'CLONE_FILES'?
tty_is_vc() is more often than not used for simple "categorization"
than validity check. E.g. in logind, we first recognize the tty
"looks like vc", and then use vtnr_from_tty() where range check
is performed and vtnr is extracted. In such cases, we want to reject
invalid vtnr from clients rather than silently carry on, hence
let's remove bound check in tty_is_vc().
Fixes#36166
Replaces #36167 and #36175
Sometimes it's nice being able to store dev_t as pointer values in
hashmaps/tables, instead of having to allocate memory for them and using
devt_hash_ops. After all dev_t is weird on Linux/glibc: glibc defines it
as 64bit entity (which hence appears as something we cannot encode in a
pointer value for compat with 32bit archs) but it actually is 32bit in
the kernel apis. Hence we can safely cut off the upper 32bit, and still
retain compat with all archs.
But let's hide this in new macros, and validate this is all correct via
a test.
systemctl has a --job-mode= argument, and adding the same argument to
systemd-run is useful for starting transient scopes with dependencies.
For example, if a transient scope BindsTo a service that is stopping,
specifying --job-mode=replace will wait for the service to stop before
starting it again, while the default job mode of "fail" will cause the
systemd-run invocation to fail.
- Drop fstat() fallback path now that we assume fdinfo
is available
- Use at_flags_normalize_nofollow()
- Accept empty path the same way as NULL
- Accept fd being AT_FDCWD and filename being "."
This doesn't make the RNG cryptographic strength, but if we have it
easily accessible, why not include the pidfd id. It is after all not
vulnerable to reuse.
Note that this drops a lot of "const" qualifiers on PidRef arguments.
That's because pidref_is_self() suddenly might end changing the PidRef
because it acquires the pidfd ID.
We had this previously already with pidfd_equal(), but this amplifies
the problem.
I guess we C's "const" doesn't really work for stuff that contains
caches, that is just conceptually constant, but not actually.
I just wanted to switch the machine id setup code to use chase() or its
changes, given it supports --root=/--image= operation. That turned out
to be a rabbit hole, and became much bigger...
let's move final processing of the filename out of the loop, and apply
it in all cases, uniformly, even if we are asked to only return the
final filename.
This also implies the new CHASE_MUST_BE_DIRECTORY flag in case the
specified path ends in a slash. This makes the rules stricter, it means
we'll be closer to how this is handled in kernel: if a path ends in a
slash it can never refer to a non-directory.
This allows using CHASE_MKDIR_0755 without CHASE_NONEXISTENT or
CHASE_PARENT, so that it will create the final component of the path
too should it be missing.
This is really useful as a mkdir_p() replacement that returns an fd to
the final component, and knows how to operate relative to a root fs.
Kinda reverts 4ea0bcb922 (which only
refused the flags combination which didn't work, instead of making it
work, which is what this commit does.)
This also corrects behaviour if CHASE_MKDIR_0755 is used in one more
way: we'll now always open the dir as O_PATH. This is generally the
better idea, but matters in particular once with allow using
CHASE_MKDIR_0755 to create the final component: we should uniformly
return an O_PATH dir that must be converted to a proper fd first before
using it.
Yu Watanabe
Michael Olbrich
Mike Yuan
Andrii Chubatiuk
Nick Rosbrook
Daan De Meyer
Lennart Poettering
Gavin Li