FORTIFY_SOURCE feature of libssp, thus checking the size of arguments to
various string and memory copy and set functions (as well as a few system
calls and other miscellany) where known at function entry. RedHat has
evidently built all "core system packages" with this option for some time.
This option should be used at the top of Makefiles (or Makefile.inc where
this is used for subdirectories) but after any setting of LIB.
This is only useful for userland code, and cannot be used in libc or in
any code which includes the libc internals, because it overrides certain
libc functions with macros. Some effort has been made to make USE_FORT=yes
work correctly for a full-system build by having the bsd.sys.mk logic
disable the feature where it should not be used (libc, libssp iteself,
the kernel) but no attempt has been made to build the entire system with
USE_FORT and doing so will doubtless expose numerous bugs and misfeatures.
Adjust the system build so that all programs and libraries that are setuid,
directly handle network data (including serial comm data), perform
authentication, or appear likely to have (or have a history of having)
data-driven bugs (e.g. file(1)) are built with USE_FORT=yes by default,
with the exception of libc, which cannot use USE_FORT and thus uses
only USE_SSP by default. Tested on i386 with no ill results; USE_FORT=no
per-directory or in a system build will disable if desired.
In particular avoid calling fclose() again once it has failed.
Also multply 'oreg' by 2 once we modify the file - so we know when to
unlink it on error.
Fixes Coverty CIDs 2535 and 2536
Allow zcat hard link to compress rather than using zcat.sh wrapper; same as uncompress.
Don't install zcat, however; gzcat seems to be living in /usr/bin/zcat at the moment.
ad any flags set (that is, st_flags is non-zero); this avoids a warning when
(un-)compressing a file on a file-system that does not support flags. Fixes
PR bin/4981.
