[PATCH v2] seedrng: import SeedRNG utility for kernel RNG seed files

[Bernhard Reutner-Fischer]

Hi!

On 5 April 2022 01:23:38 CEST, "Jason A. Donenfeld" <Jason at zx2c4.com>
wrote:

>This commit imports it into Busybox and wires up the basic config. The
>utility itself is tiny, and unlike the example code from the SeedRNG
>project, we can re-use libbb's existing hash functions, rather than
>having to ship a standalone BLAKE2s, which makes this even smaller.
>
>Signed-off-by: Jason A. Donenfeld <Jason at zx2c4.com>
>---
>Changes v1->v2:
>- Define GRND_INSECURE so that it compiles on older header collections.
>

Please also provide bloatcheck stats.
$ make baseline
# apply patch
$ make bloatcheck

We have open_read_close() which should considerably reduce size.
And there's a xopen_xwrite_close

RUNSTATEDIR is probably PID_FILE_PATH
DIV_ROUND_UP: we have a div_roundup()
strtoul: We have several checking conversion routines in include/xatonum.h
poll: maybe safe_poll()
non_creditable_seed = xasprintf("%s/%s"): concat_path_file
mkdir: bb_make_directory

Why do you open(), flock() instead of using O_EXCL?

thanks,
PS: Reminds me of the still pending
https://lists.zx2c4.com/pipermail/cgit/2015-June/002520.html
https://lists.zx2c4.com/pipermail/cgit/2015-June/002529.html
https://lists.zx2c4.com/pipermail/cgit/2015-June/002530.html