libc.h was intended to be a header for access to global libc state and
related interfaces, but ended up included all over the place because
it was the way to get the weak_alias macro. most of the inclusions
removed here are places where weak_alias was needed. a few were
recently introduced for hidden. some go all the way back to when
libc.h defined CANCELPT_BEGIN and _END, and all (wrongly implemented)
cancellation points had to include it.
remaining spurious users are mostly callers of the LOCK/UNLOCK macros
and files that use the LFS64 macro to define the awful *64 aliases.
in a few places, new inclusion of libc.h is added because several
internal headers no longer implicitly include libc.h.
declarations for __lockfile and __unlockfile are moved from libc.h to
stdio_impl.h so that the latter does not need libc.h. putting them in
libc.h made no sense at all, since the macros in stdio_impl.h are
needed to use them correctly anyway.
commits leading up to this one have moved the vast majority of
libc-internal interface declarations to appropriate internal headers,
allowing them to be type-checked and setting the stage to limit their
visibility. the ones that have not yet been moved are mostly
namespace-protected aliases for standard/public interfaces, which
exist to facilitate implementing plain C functions in terms of POSIX
functionality, or C or POSIX functionality in terms of extensions that
are not standardized. some don't quite fit this description, but are
"internally public" interfacs between subsystems of libc.
rather than create a number of newly-named headers to declare these
functions, and having to add explicit include directives for them to
every source file where they're needed, I have introduced a method of
wrapping the corresponding public headers.
parallel to the public headers in $(srcdir)/include, we now have
wrappers in $(srcdir)/src/include that come earlier in the include
path order. they include the public header they're wrapping, then add
declarations for namespace-protected versions of the same interfaces
and any "internally public" interfaces for the subsystem they
correspond to.
along these lines, the wrapper for features.h is now responsible for
the definition of the hidden, weak, and weak_alias macros. this means
source files will no longer need to include any special headers to
access these features.
over time, it is my expectation that the scope of what is "internally
public" will expand, reducing the number of source files which need to
include *_impl.h and related headers down to those which are actually
implementing the corresponding subsystems, not just using them.
the reference implementation clamps rounds to [1000,999999999]. we
further limited rounds to at most 9999999 as a defense against extreme
run times, but wrongly clamped instead of treating out-of-bounds
values as an error, thereby producing implementation-specific hash
results. fixing this should not break anything since values of rounds
this high are not useful anyway.
original FreeSec code accessed keybuf as uint32* and uint8* as well
(incorrectly), this got fixed with an union, but then it seems the
uint32* access is no longer needed so the code can be simplified
the internal sha2 hash sum functions had incorrect array size
in the prototype for the message digest argument, fixed by
using pointer so it is not misleading
it was determined in discussion that these kind of limits are not
sufficient to protect single-threaded servers against denial of
service attacks from maliciously large round counts. the time scales
simply vary too much; many users will want login passwords with rounds
counts on a scale that gives decisecond latency, while highly loaded
webservers will need millisecond latency or shorter.
still some limit is left in place; the idea is not to protect against
attacks, but to avoid the runtime of a single call to crypt being, for
all practical purposes, infinite, so that configuration errors can be
caught and fixed without bringing down whole systems. these limits are
very high, on the order of minute-long runtimes for modest systems.
previously, it was pretty much random which one of these trees a given
function appeared in. they have now been organized into:
src/linux: non-POSIX linux syscalls (possibly shard with other nixen)
src/legacy: various obsolete/legacy functions, mostly wrappers
src/misc: still mostly uncategorized; some misc POSIX, some nonstd
src/crypt: crypt hash functions
further cleanup will be done later.
Rich Felker
Timo Teräs
rofl0r
Szabolcs Nagy