It's a bit overkill to register an initcall to call a function to set
a lock to zero when not debugging, let's just declare the lock as
pre-initialized to zero.
Commit 77b98220e ("BUG/MINOR: threads: work around a libgcc_s issue with
chrooting") tried to address an issue with libgcc_s being loaded too late.
But it turns out that the symbol used there isn't present on armhf, thus
it breaks the build.
Given that the issue manifests itself during pthread_exit(), the safest
and most portable way to test this is to call pthread_exit(). For this
we create a dummy thread which exits, during the early boot. This results
in the relevant library to be loaded if needed, making sure that a later
call to pthread_exit() will still work. It was tested to work fine under
linux on the following platforms:
glibc:
- armhf
- aarch64
- x86_64
- sparc64
- ppc64le
musl:
- mipsel
Just running the code under strace easily shows the call in the dummy
thread, for example here on armhf:
$ strace -fe trace=file ./haproxy -v 2>&1 | grep gcc_s
[pid 23055] open("/lib/libgcc_s.so.1", O_RDONLY|O_CLOEXEC) = 3
The code was isolated so that it's easy to #ifdef it out if needed.
This should be backported where the patch above is backported (likely
2.0).
Previous commit 77b98220e ("BUG/MINOR: threads: work around a libgcc_s
issue with chrooting") broke the build on cygwin. I didn't even know we
supported threads on cygwin. But the point is that it's actually the
glibc-based libpthread which requires libgcc_s, so in absence of other
reports we should not apply the workaround on other libraries.
This should be backported along with the aforementioned patch.
Sander Hoentjen reported another issue related to libgcc_s in issue #671.
What happens is that when the old process quits, pthread_exit() calls
something from libgcc_s.so after the process was chrooted, and this is
the first call to that library, causing an attempt to load it. In a
chroot, this fails, thus libthread aborts. The behavior widely differs
between operating systems because some decided to use a static build for
this library.
In 2.2 this was resolved as a side effect of a workaround for the same issue
with the backtrace() call, which is also in libgcc_s. This was in commit
0214b45 ("MINOR: debug: call backtrace() once upon startup"). But backtraces
are not necessarily enabled, and we need something for older versions.
By inspecting a significant number of ligcc_s on various gcc versions and
platforms, it appears that a few functions have been present since gcc 3.0,
one of which, _Unwind_Find_FDE() has no side effect (it only returns a
pointer). What this patch does is that in the thread initialization code,
if built with gcc >= 3.0, a call to this function is made in order to make
sure that libgcc_s is loaded at start up time and that there will be no
need to load it upon exit.
An easy way to check which libs are loaded under Linux is :
$ strace -e trace=openat ./haproxy -v
With this patch applied, libgcc_s now appears during init.
Sander confirmed that this patch was enough to put an end to the core
dumps on exit in 2.0, so this patch should be backported there, and maybe
as far as 1.8.
This patch fixes all the leftovers from the include cleanup campaign. There
were not that many (~400 entries in ~150 files) but it was definitely worth
doing it as it revealed a few duplicates.
There's no point splitting the file in two since only cfgparse uses the
types defined there. A few call places were updated and cleaned up. All
of them were in C files which register keywords.
There is nothing left in common/ now so this directory must not be used
anymore.
global.h was one of the messiest files, it has accumulated tons of
implicit dependencies and declares many globals that make almost all
other file include it. It managed to silence a dependency loop between
server.h and proxy.h by being well placed to pre-define the required
structs, forcing struct proxy and struct server to be forward-declared
in a significant number of files.
It was split in to, one which is the global struct definition and the
few macros and flags, and the rest containing the functions prototypes.
The UNIX_MAX_PATH definition was moved to compat.h.
A few includes were missing in each file. A definition of
struct polled_mask was moved to fd-t.h. The MAX_POLLERS macro was
moved to defaults.h
Stdio used to be silently inherited from whatever path but it's needed
for list_pollers() which takes a FILE* and which can thus not be
forward-declared.
And also rename standard.c to tools.c. The original split between
tools.h and standard.h dates from version 1.3-dev and was mostly an
accident. This patch moves the files back to what they were expected
to be, and takes care of not changing anything else. However this
time tools.h was split between functions and types, because it contains
a small number of commonly used macros and structures (e.g. name_desc)
which in turn cause the massive list of includes of tools.h to conflict
with the callers.
They remain the ugliest files of the whole project and definitely need
to be cleaned and split apart. A few types are defined there only for
functions provided there, and some parts are even OS-specific and should
move somewhere else, such as the symbol resolution code.
This splits the hathreads.h file into types+macros and functions. Given
that most users of this file used to include it only to get the definition
of THREAD_LOCAL and MAXTHREADS, the bare minimum was placed into thread-t.h
(i.e. types and macros).
All the thread management was left to haproxy/thread.h. It's worth noting
the drop of the trailing "s" in the name, to remove the permanent confusion
that arises between this one and the system implementation (no "s") and the
makefile's option (no "s").
For consistency, src/hathreads.c was also renamed thread.c.
A number of files were updated to only include thread-t which is the one
they really needed.
Some future improvements are possible like replacing empty inlined
functions with macros for the thread-less case, as building at -O0 disables
inlining and causes these ones to be emitted. But this really is cosmetic.
