Double newlines (i.e. one empty lines) are great to structure code. But
let's avoid triple newlines (i.e. two empty lines), quadruple newlines,
quintuple newlines, …, that's just spurious whitespace.
It's an easy way to drop 121 lines of code, and keeps the coding style
of our sources a bit tigther.
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 adds a new flavour of strextend(), called
strextend_with_separator(), which takes an optional separator string. If
specified, the separator is inserted between each appended string, as
well as before the first one, but only if the original string was
non-empty.
This new call is particularly useful when appending new options to mount
option strings and suchlike, which need to be comma-separated, and
initially start out from an empty string.
explicit_bzero was added in glibc 2.25. Make use of it.
explicit_bzero is hardcoded to zero the memory, so string erase now
truncates the string, instead of overwriting it with 'x'. This causes
a visible difference only in the journalctl case.
In contrast to ascii_strcasecmp_nn() it takes two character buffers with their individual length. It will then compare
the buffers up the smaller size of the two buffers, and finally the length themselves.
memory_erase() so far just called memset(), which the compiler might
optimize away under certain conditions if it feels there's benefit in
it. C11 knows a new memset_s() call that is like memset(), but may not
be optimized away. Ideally, we'd just use that call, but glibc currently
does not support it. Hence, implement our own simplistic version of it.
We use a GCC pragma to turn off optimization for this call, and also use
the "volatile" keyword on the pointers to ensure that gcc will use the
pointers as-is. According to a variety of internet sources, either one
does the trick. However, there are also reports that at least the
volatile thing isn't fully correct, hence let's add some snake oil and
employ both techniques.
https://news.ycombinator.com/item?id=4711346