The reason why get_process_cmdline() is so complicated is that we
need to escape and quote arguments for building a single result
string.
That's necessary when we want to log or print the command line.
However, when we want to parse the command line, it is not necessary
that the result is a single string, but can be strv.
This will be used when we parse the command line.
The /proc/self/fd/ interface cannot be used to follow symlinks pinned
via O_PATH. Add a comment + test for that. Moreover, using fd_reopen()
with O_NOFOLLOW cannot work. Add an explicit check and test for that, to
make behaviour uniform.
Chasing symlinks is a core function that's used in a lot of places
so it deservers a less verbose names so let's rename it to chase()
and chaseat().
We also slightly change the pattern used for the chaseat() helpers
so we get chase_and_openat() and similar.
This is a combination of fdopen() and fd_reopen(). i.e. it first reopens
the fd, and then converts that into a FILE*.
We do this at various places already manually. let's move this into a
helper call of its own.
The test files are /proc//auxv files copies from various architecutres
signified by the file name suffix.
Those tests are fairly simple, but when we run them on n architectures, we do
~n² cross-arch tests.
Whenever we're going to close all file descriptors, we tend to close
the log and set it into open when needed mode. When this is done with
the logging target set to LOG_TARGET_AUTO, we run into issues because
for every logging call, we'll check if stderr is connected to the
journal to determine where to send the logging message. This check
obviously stops working when we close stderr, so we settle the log
target before we do that so that we keep using the same logging
target even after stderr is closed.
Useful in combination with CHASE_PARENT to get a directory file
descriptor to the parent directory of the resolved path and the
filename of the resolved path in the parent directory (which might
not be the same as the filename of the input path because of symlinks).
Now that we have reference counting, it's useful to be able to push
single key values onto the log context separately, so that we don't
have to allocate new storage to join the separate string together into
a single field which means we won't be able to reuse a context containing
the same field.
Let's try to optimize against pushing the same fields multiple times
onto the log context. To achieve this we make the log context reference
counted and return an existing context object if it's using the same
fields.
A consequence of this is that we have to make sure attaching/detaching
is coupled to the lifetime of the context object, so we make the attach
and detach functions private for now. If we need independent attach/detach
in the future, we can make that work with some extra complexity but since
we don't need it yet, let's not support it for now.
For those token types that support matching of alternative patterns,
their token values are interpreted as nulstr, so make sure the parser
does the right thing and makes these token values terminated by two
subsequent NULs so they could be safely interpreted as nulstr.
Before this fix, the following rules would result to "echo foo" invocation:
ENV{foo}=", RUN"
ENV{foo}=="bar", RUN+="echo foo"
because the value of `ENV{foo}` is treated as nulstr, and it used to match
against alternative patterns, in this case `bar`, `, RUN`, and `="echo foo`.
Fixes: 25de7aa7b9 ("udev: modernize udev-rules.c")
Currently, when CHASE_PARENT is specified, we chase the parent directory
of the symlink itself. Let's change this and chase the parent directory
of the symlink target so that trying to open the actual file later with
O_NOFOLLOW doesn't fail with ELOOP.
To get the current behavior, callers can add CHASE_NOFOLLOW to chase
the parent directory of the symlink itself.
Currently, when CHASE_MKDIR_0755 is specified, we create all components
of the path as directories. Instead, let's change the flag to only create
parent directories and leave the final component of the PATH untouched.
Also, allow CHASE_NONEXISTENT with CHASE_MKDIR_0755 now that it doesn't
create all components anymore.
Finally, rework chase_symlinks_and_open() and chase_symlinkat_at_and_open()
to always chase the parent directory and use xopenat() to open the final
component of the path. This allows us to pass O_CREAT to create the file or
directory (O_DIRECTORY) if it is missing. If CHASE_PARENT is configured, we
just reopen the parent directory that we chased.
Yu Watanabe
Luca Boccassi
OMOJOLA JOSHUA DAMILOLA
Lennart Poettering
Daan De Meyer
Zbigniew Jędrzejewski-Szmek
Dmitry V. Levin
Mike Yuan
OMOJOLA JOSHUA