On Sat, Jan 20, 2024 at 10:48:12AM +0100, Emile 'iMil' Heitor wrote:
Hi,
that's from sysctl.c:
case CTLTYPE_STRING: {
unsigned char buf[1024], *tbuf;
tbuf = buf;
sz = sizeof(buf);
rc = prog_sysctl(&name[0], namelen, tbuf, &sz, NULL, 0);
The sysctl command first tries with a buffer of 1024 bytes
and retries with the right size when that was too small.
Compared to "probing" with a NULL buffer this saves a round trip
to the kernel for most sysctls.
A simple helper function would always return the needed size and only
copy out when oldp was set. sysctl will check the returned *oldlenp
against the value passed by the caller and return ENOMEM as appropriate.
Greetings,
--
Michael van Elst
Internet: mlel...@serpens.de
"A potential Snark may lurk in every tree."
