On Mon, May 17, 2021 at 01:46:46PM -0400, Randall S. Becker wrote: > On Wed, 17 Feb 2021 21:48:36, Jeff Hostetler wrote: > > >Here is V4 of my "Simple IPC" series. It addresses Gábor's comment WRT > >shutting down the server to make unit tests more predictable on CI servers. > >(https://lore.kernel.org/git/20210213093052.GJ1015009@xxxxxxxxxx) > > I missed this at the time, but it appears that ipc-unix-socket.c > forces a dependency on pthreads for Git under Unix-like platforms. > This is probably not a correct assumption (or likely intended), but > causes git to no longer build on NonStop x86 and ia64 as of > 2.32.0-rc0. I am not suggesting undoing this, but amending to make the > change more sensitive to a lack of pthread support. > pthread_sigmask() showed up as an undefined external: Hrm. Usually we do not assume that threads are available. For "async" stuff via run-command, we allow it to be implemented via fork(), and insist that the async process talk back to us only over a pipe descriptor (so it works whether it's a thread or a separate process). In cases where we use worker threads for performance (like index-pack or pack-objects), we just run a single "thread" instead, waiting for it to complete. In the simple-ipc API, there's an explicit "async" interface. But it's not clear to me how rich it expects the communication with the caller to be (i.e., whether we could get away with the fork() trick here). Or if it would be OK for the threading to remain an implementation detail, with one "worker" upon whom we wait for completion. > **** ERROR **** [1210]: > libgit.a(ipc-unix-socket.o): In function `thread_block_sigpipe': > ipc-unix-socket.o(.text+0xb87): unresolved reference to pthread_sigmask. > > On NonStop, pthread_sigmask is defined in -lput or -lspt, which are not used in our build – and would cause a bunch of other issues > if referenced. The build does define NO_PTHREADS. So yeah, you hit that problem because you only have a sort-of-pthreads-ish case. But it seems like a system which truly has no pthread support at all and defines NO_PTHREADS to tell us so will have much more of its compilation broken (because it's also missing obvious bits like pthread_create()). We already make simple-ipc compilation conditional on NO_UNIX_SOCKETS. I think we could probably just do the same for NO_PTHREADS? Something like: diff --git a/Makefile b/Makefile index 3a2d3c80a8..bd7fe0fc24 100644 --- a/Makefile +++ b/Makefile @@ -1687,14 +1687,20 @@ ifdef NO_UNIX_SOCKETS else LIB_OBJS += unix-socket.o LIB_OBJS += unix-stream-server.o +endif + +# All simple-ipc requires threads, and then individual +# mechanisms have their own requirements. +ifndef NO_PTHREADS + BASIC_CFLAGS += -DSUPPORTS_SIMPLE_IPC LIB_OBJS += compat/simple-ipc/ipc-shared.o +ifndef NO_UNIX_SOCKETS LIB_OBJS += compat/simple-ipc/ipc-unix-socket.o endif - ifdef USE_WIN32_IPC - LIB_OBJS += compat/simple-ipc/ipc-shared.o LIB_OBJS += compat/simple-ipc/ipc-win32.o endif +endif ifdef NO_ICONV BASIC_CFLAGS += -DNO_ICONV diff --git a/simple-ipc.h b/simple-ipc.h index dc3606e30b..0f58be7945 100644 --- a/simple-ipc.h +++ b/simple-ipc.h @@ -4,11 +4,6 @@ /* * See Documentation/technical/api-simple-ipc.txt */ - -#if defined(GIT_WINDOWS_NATIVE) || !defined(NO_UNIX_SOCKETS) -#define SUPPORTS_SIMPLE_IPC -#endif - #ifdef SUPPORTS_SIMPLE_IPC #include "pkt-line.h"
