Various tty types come up with cols/rows not initialized (i.e. set to
zero). Let's detect these cases, and return a better error than EIO,
simply to make things easier to debug.
/dev/console is sometimes a symlink in container managers. Let's handle
that correctly, and resolve the symlink, and not consider the data from
/sys/ in that case.
It doesn't really make sense to have that in dev-setup.c, which is
mostly about setting up /dev/, creating device nodes and stuff.
let's move it to the other stuff that deals with /dev/console's
peculiarities.
Numerous fixes:
1. use vtnr_from_tty() to parse out VT number from tty path
2. open tty for write only when we want to output just ansi sequences
3. open tty in asynchronous mode, and apply a timeout, just to be safe
4. propagate error from writing (most callers ignore it anyway, might as
well pass it along correctly)
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]
Let's update the commentary a bit. Also, use a time-out of 100ms rather
than 50ms for this, simply to unify on the same value used in
vt_disallocate() in a similar case.
Let's put "terminal_" as prefix, like with the other reset calls, and
let's make clear that this only encapsulates the ioctl-based reset
logic, not the ANSI sequence based reset logic.
ESC c is a (vaguely defined) "reset to initial state" ANSI sequence.
Many terminals clear the screen in this case, but that's a bit drastic I
think for most resets.
ESC c was added to the reset logic in
00bc83a275 (i.e. very recently), and I
don't think the effect was clear at that time.
Let's keep the ESC c in place however when we actually want to clear the
screen. Hence move it from reset_terminal_fd() into vt_disallocate().
Fixes: #33689
When we are talking to a serial terminal quite commonly the dimensions
are not set properly, because the serial protocol has not handshake or
similar to transfer this information.
However, we can derive the dimensions via ANSI sequences too, which
should get us the right information, since ANSI sequences are
interpreted by the final terminal, rather than an intermediary local tty
driver (which is where TIOCGWINSZ is interpreted).
This adds a helper call that gets the dimensions this way.
Let's prefix these functions with the subsystem name, and clean them up
a bit. Specifically, drop the error logging, it's entirely duplicative,
since every single caller does it anyway.
Let's add an extra safety check: before issuing the ansi sequence to
query the bg color, let's make sure input and output fd actually
reference the same tty. because otherwise it's unlikely we'll be able to
read back the response from the tty driver.
This is mostly just paranoia.
If we only read partial information from the tty we ended up parsing it
again and again, confusing the state machine. hence, return how much
data we actually processed and drop it from the buffer.
We use this at various places, let's unify this in one global constant.
This changes flags in crash-handler.c in a tiny irrelevant way: we ask
syscalls to be continued on signal arrival, which we previously didn't.
But that shouldn't change anything, the only thing we'll do in the
relevant process is call raise(), and that's it, hence there definitely
are no syscalls to restart or not to restart.
Follow up for 8b3b01c4b7
We switch to PROJECT_VERSION instead of PROJECT_VERSION_FULL where
we report our version and which is likely being parsed to avoid
breaking compat. If we didn't, the output would change from systemd
255 to systemd 255.1 which could break various tools.
The previous commit tries to extract a substring from the
extension-release suffix, but that is not right, it's only the
images that need to be versioned and extracted, use the extension-release
suffix as-is. Otherwise if it happens to contain a prefix that
matches the wrong image, it will be taken into account.
Follow-up for 37543971af
Our variables for internal libraries are named 'libfoo' for the shared lib
variant, and 'libfoo_static' for the static lib variant. The only exception was
libbasic, because we didn't have a shared variant for it. But let's rename it
for consitency. This makes the build config easier to understand.
In the unlikely event that sandboxes block statx() but let
name_to_handle_at() through it's a good way to determine the root inode
of the namespace, since its parent inode will have the same FID and
mnt_id.
Newer kernels support a new flag for name_to_handle_at(): AT_HANDLE_FID.
This flag is supposed to return an identifier for an inode that we can
use for checking inode identity. It's supposed to be a replacement for
checking .st_ino which doesn't work anymore today because inode numbers
are no longer unique on file systems (not on overlayfs, and not on btrfs
for example). Hence, be a good citizen and add infrastructure to support
AT_HANDLE_FID. Unfortunately that doesn't work for old kernels, hence
add a fallback logic: if we can use the flag, use it. If we cannot use
name_to_handle_at() without it, which might give us a good ID too. But
of course tha tcan fail as well, which callers have to check.
