This reverts a major part of: e17c95af8e
Using format strings for concatenating strings is pretty unefficient,
and using PATH_MAX buffers unpretty as well. Let's revert to using
strjoina() as before.
However, to fix the fuzz issue at hand, let's explicitly verify the two
input strings ensuring they are valid path names. This includes a length
check (to 2K each), thus making things prettier, faster and using less
memory again.
The kernel can be compiled without support for any memory.swap.* files, or
it can be disabled at boot time with the 'swapaccount=0' boot parameter,
so if the file doesn't exist log warning indicating the kernel doesn't
support the file and the user may need to try using the 'swapaccount=1'
boot param.
Note that the actual error from the call to fopen() is ENOENT, but
that is translated into ENODATA in cg_get_attribute_as_uint64()
The kernel still provides the /proc and cgroup pressure files even
if its psi support is disabled, so we need to actually read the files
to verify they don't return -EOPNOTSUPP
These macros will log a message at the specified level only the first time
they are called. On all later calls, if the specified level is debug, the
logs will be suppressed; otherwise the message will be logged at debug.
Every location that this macro is used, it will be true the first
time it's checked, then false each time after that.
This can be useful for things such as one-time logging.
If the journal file being processed is archivied, seqnum_id will not be
initialized before being passed on, and coverity complains.
Initialize it to zero.
CID #1453235
Hardcoding major numbers sucks. And we generally don't do it, except
when determining whether something is a PTY. Thing though is that we
don't actually need to do that here either, hence don#t.
This new option does three things for a host user specified via
--bind-user=:
1. Bind mount the home directory from the host directory into
/run/host/home/<username>
2. Install an additional user namepace UID/GID mapping mapping the host
UID/GID of the host user to an unused one from the container in the range
60514…60577.
3. Synthesize a user/group record for the user/group under the same name
as on the host, with minimized information, and the UID/GID set to
the mapped UID/GID. This data is written to /run/host/userdb/ where
nss-system will pick it up.
This should make sharing users and home directories from host into the
container pretty seamless, under some conditions:
1. User namespacing must be used.
2. The host UID/GID of the user/group cannot be in the range assigned to
the container (kernel already refuses this, as this would mean two
host UIDs/GIDs might end up being mapped to the same continer
UID/GID.
3. There's a free UID/GID in the aforementioned range in the container,
and the name of the user/group is not used in the container.
4. Container payload is new enough to include an nss-systemd version
that picks up records from /run/host/userdb/
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 is a wrapper around malloc_usable_size() but is typesafe, and
divides by the element size.
A test it is also added ensuring what it does it does correcly.
