Add MALLOC_CHECK_ and MALLOC_PERTURB_ libc env to the test suite for detecting heap corruption

Recent versions of Linux libc (later than 5.4.23) and glibc (2.x)
include a malloc() implementation which is tunable via environment
variables. When MALLOC_CHECK_ is set, a special (less efficient)
implementation is used which is designed to be tolerant against
simple errors, such as double calls of free() with the same argument,
or overruns of a single byte (off-by-one bugs). When MALLOC_CHECK_
is set to 3, a diagnostic message is printed on stderr
and the program is aborted.

Setting the MALLOC_PERTURB_ environment variable causes the malloc
functions in libc to return memory which has been wiped and clear
memory when it is returned.
Of course this does not affect calloc which always does clear the memory.

The reason for this exercise is, of course, to find code which uses
memory returned by malloc without initializing it and code which uses
code after it is freed. valgrind can do this but it's costly to run.
The MALLOC_PERTURB_ exchanges the ability to detect problems in 100%
of the cases with speed.

The byte value used to initialize values returned by malloc is the byte
value of the environment value. The value used to clear memory is the
bitwise inverse. Setting MALLOC_PERTURB_ to zero disables the feature.

This technique can find hard to detect bugs.
It is therefore suggested to always use this flag (at least temporarily)
when testing out code or a new distribution.

But the test suite can use also valgrind(memcheck) via 'make valgrind'
or 'make GIT_TEST_OPTS="--valgrind"'.

Memcheck wraps client calls to malloc(), and puts a "red zone" on
each end of each block in order to detect access overruns.
Memcheck already detects double free() (up to the limit of the buffer
which remembers pending free()). Thus memcheck subsumes all the
documented coverage of MALLOC_CHECK_.

If MALLOC_CHECK_ is set non-zero when running memcheck, then the
overruns that might be detected by MALLOC_CHECK_ would be overruns
on the wrapped blocks which include the red zones.  Thus MALLOC_CHECK_
would be checking memcheck, and not the client.  This is not useful,
and actually is wasteful.  The only possible [documented] advantage
of using MALLOC_CHECK_ and memcheck together, would be if MALLOC_CHECK_
detected duplicate free() in more cases than memcheck because memcheck's
buffer is too small.

Therefore we don't use MALLOC_CHECK_ and valgrind(memcheck) at the
same time.

Signed-off-by: Elia Pinto <gitter.spiros@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add userdiff patterns for Ada

Add Ada xfuncname and wordRegex patterns to the list of builtin
patterns.

Signed-off-by: Adrian Johnson <ajohnson@redneon.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
mailinfo: do not concatenate charset= attribute values from mime headers

"Content-type: text/plain; charset=UTF-8" header should not appear
twice in the input, but it is always better to gracefully deal with
such a case.  The current code concatenates the value to the values
we have seen previously, producing nonsense such as "utf8UTF-8".

Instead of concatenating, forget the previous value and use the last
value we see.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
make poll available for other platforms lacking it

move poll.[ch] out of compat/win32/ into compat/poll/ and adjust
Makefile with the changed paths. Adding comments to Makefile about
how/when to enable it and add logic for this

Signed-off-by: Joachim Schmitz <jojo@schmitz-digital.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
fix some win32 specific dependencies in poll.c

In order for non-win32 platforms to be able to use poll.c, #ifdef the
inclusion of two header files properly

Signed-off-by: Joachim Schmitz <jojo@schmitz-digital.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
poll() exits too early with EFAULT if 1st arg is NULL

If poll() is used as a milli-second sleep, like in help.c, by passing a NULL
in the 1st and a 0 in the 2nd arg, it exits with EFAULT.

As per Paolo Bonzini, the original author, this is a bug and to be fixed
Like in this commit, which is not to exit if the 2nd arg is 0. It got fixed
In gnulib in the same manner the other day.

Signed-off-by: Joachim Schmitz <jojo@schmitz-digital.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
make poll() work on platforms that can't recv() on a non-socket

This way it just got added to gnulib too the other day.

Signed-off-by: Joachim Schmitz <jojo@schmitz-digital.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
MALLOC_CHECK: various clean-ups

The most important in this change is to avoid affecting anything
when test-lib is used from perf-lib.  It also limits the effect of
the MALLOC_CHECK only to what is run inside the actual test, and
uses a fixed MALLOC_PERTURB_ in order to avoid hurting repeatability
of the tests.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
t/test-lib: make sure Git has already been built

When tests were run without building git, they stopped with:

    .: 54: Can't open /path/to/git/source/t/../GIT-BUILD-OPTIONS

Move the check that makes sure that git has already been built from
t0000 to test-lib, so that any test will do so before it runs.

Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Doc: shallow clone deepens _to_ new depth

Clarify that 'depth=' specifies the new depth from the remote's
branch tip. It does not add the depth to the existing shallow clone.
(details from pack-protocol.txt).
Clarify that tags are not fetched. (details from shallow.txt)

Signed-off-by: Philip Oakley <philipoakley@iee.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Doc: separate gitignore pattern sources

Use separate bulleted paragraphs for the three different gitignore
pattern sources.

Signed-off-by: Philip Oakley <philipoakley@iee.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Doc add: link gitignore

Use a gitignore link rather than the gitrepository-
layout link.

Signed-off-by: Philip Oakley <philipoakley@iee.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Doc clean: add See Also link

'git clean' is controlled by gitignore. Provide See Also link for it.

Use of core.excludesfile is implied.

Signed-off-by: Philip Oakley <philipoakley@iee.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Doc branch: show -vv option and alternative

Indicate that the -v option can be given twice in the short options.
Without it users pass over the option. Also indicate the alternate
'git remote show' method.

Signed-off-by: Philip Oakley <philipoakley@iee.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Documentation/Makefile: Allow custom XMLTO binary

Signed-off-by: Dave Borowitz <dborowitz@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Port to HP NonStop

Includes the addition of some new defines and their description for others to use.

Signed-off-by: Joachim Schmitz <jojo@schmitz-digital.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Revert "completion: fix shell expansion of items"

This reverts commit 25ae7cfd19c8f21721363c64163cd5d9d1135b20.

That patch does fix expansion of weird variables in some
simple tests, but it also seems to break other things, like
expansion of refs by "git checkout".

While we're sorting out the correct solution, we are much
better with the original bug (people with metacharacters in
their completions occasionally see an error message) than
the current bug (ref completion does not work at all).

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

* maint:
  Revert "completion: fix shell expansion of items"
Merge branch 'db/doc-custom-xmlto'

* db/doc-custom-xmlto:
  Documentation/Makefile: Allow custom XMLTO binary
Merge branch 'po/maint-docs'

Various documentation fixups.

* po/maint-docs:
  Doc branch: show -vv option and alternative
  Doc clean: add See Also link
  Doc add: link gitignore
  Doc: separate gitignore pattern sources
  Doc: shallow clone deepens _to_ new depth