Dynamic loading of DLL functions is duplicated in several places in Git
for Windows' source code.

This patch adds a pair of macros to simplify the process: the
DECLARE_PROC_ADDR(<dll>, <return-type>, <function-name>,
...<function-parameter-types>...) macro to be used at the beginning of a
code block, and the INIT_PROC_ADDR(<function-name>) macro to call before
using the declared function. The return value of the INIT_PROC_ADDR()
call has to be checked; If it is NULL, the function was not found in the
specified DLL.

Example:

        DECLARE_PROC_ADDR(kernel32.dll, BOOL, CreateHardLinkW,
                          LPCWSTR, LPCWSTR, LPSECURITY_ATTRIBUTES);

        if (!INIT_PROC_ADDR(CreateHardLinkW))
                return error("Could not find CreateHardLinkW() function";

	if (!CreateHardLinkW(source, target, NULL))
		return error("could not create hardlink from %S to %S",
			     source, target);
	return 0;

Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

If realloc() fails then the original buffer is still valid.  Free it
before exiting the function.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Some Windows SDK lacks pthread_sigmask() implementation and fails
to compile the recently updated "git push" codepath that uses it.

* jk/push-client-deadlock-fix:
  Windows: only add a no-op pthread_sigmask() when needed
  Windows: add pthread_sigmask() that does nothing

In f924b52 (Windows: add pthread_sigmask() that does nothing,
2016-05-01), we introduced a no-op for Windows. However, this breaks
building Git in Git for Windows' SDK because pthread_sigmask() is
already a no-op there, #define'd in the pthread_signal.h header in
/mingw64/x86_64-w64-mingw32/include/.

Let's wrap the definition of pthread_sigmask() in a guard that skips
it when compiling with MinGW-w64' headers.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

A previous change introduced a call to pthread_sigmask() in order to block
SIGPIPE in a thread. Since there are no signal facilities on Windows that
are similar to POSIX signals, just ignore the request to block the signal.
In the particular case, the effect of blocking SIGPIPE on POSIX is that
write() calls return EPIPE when the reader closes the pipe. This is how
write() behaves on Windows.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

* js/pthread-exit-emu-windows:
  Mark win32's pthread_exit() as NORETURN

The pthread_exit() function is not expected to return. Ever. On Windows,
we call ExitThread() whose documentation claims: "Ends the calling
thread", i.e. there is no condition in which this function simply
returns: https://msdn.microsoft.com/en-us/library/windows/desktop/ms682659

While at it, fix the return type to be void, as per
http://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_exit.html

Pointed out by Jeff King, helped by Stefan Naewe, Junio Hamano &
Johannes Sixt.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Update various codepaths to avoid manually-counted malloc().

* jk/tighten-alloc: (22 commits)
  ewah: convert to REALLOC_ARRAY, etc
  convert ewah/bitmap code to use xmalloc
  diff_populate_gitlink: use a strbuf
  transport_anonymize_url: use xstrfmt
  git-compat-util: drop mempcpy compat code
  sequencer: simplify memory allocation of get_message
  test-path-utils: fix normalize_path_copy output buffer size
  fetch-pack: simplify add_sought_entry
  fast-import: simplify allocation in start_packfile
  write_untracked_extension: use FLEX_ALLOC helper
  prepare_{git,shell}_cmd: use argv_array
  use st_add and st_mult for allocation size computation
  convert trivial cases to FLEX_ARRAY macros
  use xmallocz to avoid size arithmetic
  convert trivial cases to ALLOC_ARRAY
  convert manual allocations to argv_array
  argv-array: add detach function
  add helpers for allocating flex-array structs
  harden REALLOC_ARRAY and xcalloc against size_t overflow
  tree-diff: catch integer overflow in combine_diff_path allocation
  ...

If our size computation overflows size_t, we may allocate a
much smaller buffer than we expected and overflow it. It's
probably impossible to trigger an overflow in most of these
sites in practice, but it is easy enough convert their
additions and multiplications into overflow-checking
variants. This may be fixing real bugs, and it makes
auditing the code easier.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>