sxinit starts Xserver and ~/.xinitrc script.
All sxinit arguments are passed to Xserver as is.
(misc)
The full path and arguments to Xorg are hardcoded to prevent users
of placing another binary into the search path,
which would be executed with admin rights.
For the same reason, it shouldn't be possible to submit
arbitrary arguments to xorg for users,
nor should Xorg itself be suid or executable by users.
The xserver is a quite complex executable, so it is definitely more secure
having a small static binary like sxinit being suid,
which can be checked for security flaws,
than having the xserver suid with known vulnerabilities.
All arguments submitted to sxinit are submitted to the script xinitrc,
which is parsed and executed by /bin/sh.
The suid rights of sxinit are droppped, as soon the xserver runs.
When there's no /home/user/.xinitrc file present,
the default /etc/X11/xinitrc script is executed.
'minilib.conf' is a configuration file to (optionally) download Makefile.minilib
and minilib.h from github, and compile sxinit statically linked with minilib
(github.com/michael105/minilib) to ~3.5kB.
'make -f minilib.conf'
There is the possibility (and IMHO advantage) of being able to see
the complete sources, including all used parts of minilib,
with 'SHOWSOURCE=1 make -f minilib.conf'
When skipping through the (mostly unused) type definitions and praedeclarations,
this gets down to around 500 locs.