Subject: [PATCH] simple-ipc: correct ifdefs when NO_PTHREADS is defined

From: "Jeff Hostetler via GitGitGadget" <[email-masked]>
Date: Tue, 18 May 2021 15:36:31 +0000

From: Jeff Hostetler <[email-masked]>

Simple IPC always requires threads (in addition to various
platform-specific IPC support).  Fix the ifdefs in the Makefile
to define SUPPORTS_SIMPLE_IPC when appropriate.

Previously, the Unix version of the code would only verify that
Unix domain sockets were available.

This problem was reported here:
https://lore.kernel.org/git/[email-masked]/T/#m08be8f1942ea8a2c36cfee0e51cdf06489fdeafc

Reported-by: Randall S. Becker <[email-masked]>
Helped-by: Jeff King <[email-masked]>
Signed-off-by: Jeff Hostetler <[email-masked]>
---
    simple-ipc: correct ifdefs when NO_PTHREADS is defined
    
    Simple IPC always requires threads (in addition to various
    platform-specific IPC support). Fix the ifdefs in the Makefile to define
    SUPPORTS_SIMPLE_IPC when appropriate.
    
    Previously, the Unix version of the code would only verify that Unix
    domain sockets were available.
    
    This problem was reported here:
    https://lore.kernel.org/git/[email-masked]/T/#m08be8f1942ea8a2c36cfee0e51cdf06489fdeafc
    
    Reported-by: Randall S. Becker [email-masked] Helped-by: Jeff
    King [email-masked] Signed-off-by: Jeff Hostetler [email-masked]

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-955%2Fjeffhostetler%2Ffixup-simple-ipc-no-pthreads-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-955/jeffhostetler/fixup-simple-ipc-no-pthreads-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/955

 Makefile                            | 14 ++++++++++++--
 compat/simple-ipc/ipc-unix-socket.c |  8 ++++++++
 compat/simple-ipc/ipc-win32.c       |  4 ++++
 simple-ipc.h                        |  4 ----
 4 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/Makefile b/Makefile
index 3a2d3c80a81a..30df67fd62eb 100644
--- a/Makefile
+++ b/Makefile
@@ -1687,13 +1687,23 @@ ifdef NO_UNIX_SOCKETS
 else
 	LIB_OBJS += unix-socket.o
 	LIB_OBJS += unix-stream-server.o
-	LIB_OBJS += compat/simple-ipc/ipc-shared.o
-	LIB_OBJS += compat/simple-ipc/ipc-unix-socket.o
 endif
 
+# Simple-ipc requires threads and platform-specific IPC support.
+# (We group all Unix variants in the top-level else because Windows
+# also defines NO_UNIX_SOCKETS.)
 ifdef USE_WIN32_IPC
+	BASIC_CFLAGS += -DSUPPORTS_SIMPLE_IPC
 	LIB_OBJS += compat/simple-ipc/ipc-shared.o
 	LIB_OBJS += compat/simple-ipc/ipc-win32.o
+else
+ifndef NO_PTHREADS
+ifndef NO_UNIX_SOCKETS
+	BASIC_CFLAGS += -DSUPPORTS_SIMPLE_IPC
+	LIB_OBJS += compat/simple-ipc/ipc-shared.o
+	LIB_OBJS += compat/simple-ipc/ipc-unix-socket.o
+endif
+endif
 endif
 
 ifdef NO_ICONV
diff --git a/compat/simple-ipc/ipc-unix-socket.c b/compat/simple-ipc/ipc-unix-socket.c
index 38689b278df3..c23b17973983 100644
--- a/compat/simple-ipc/ipc-unix-socket.c
+++ b/compat/simple-ipc/ipc-unix-socket.c
@@ -6,10 +6,16 @@
 #include "unix-socket.h"
 #include "unix-stream-server.h"
 
+#ifdef SUPPORTS_SIMPLE_IPC
+
 #ifdef NO_UNIX_SOCKETS
 #error compat/simple-ipc/ipc-unix-socket.c requires Unix sockets
 #endif
 
+#ifdef NO_PTHREADS
+#error compat/simple-ipc/ipc-unix-socket.c requires pthreads
+#endif
+
 enum ipc_active_state ipc_get_active_state(const char *path)
 {
 	enum ipc_active_state state = IPC_STATE__OTHER_ERROR;
@@ -997,3 +1003,5 @@ void ipc_server_free(struct ipc_server_data *server_data)
 	free(server_data->fifo_fds);
 	free(server_data);
 }
+
+#endif /* SUPPORTS_SIMPLE_IPC */
diff --git a/compat/simple-ipc/ipc-win32.c b/compat/simple-ipc/ipc-win32.c
index 8f89c02037e3..958bb562ebb6 100644
--- a/compat/simple-ipc/ipc-win32.c
+++ b/compat/simple-ipc/ipc-win32.c
@@ -4,6 +4,8 @@
 #include "pkt-line.h"
 #include "thread-utils.h"
 
+#ifdef SUPPORTS_SIMPLE_IPC
+
 #ifndef GIT_WINDOWS_NATIVE
 #error This file can only be compiled on Windows
 #endif
@@ -749,3 +751,5 @@ void ipc_server_free(struct ipc_server_data *server_data)
 
 	free(server_data);
 }
+
+#endif /* SUPPORTS_SIMPLE_IPC */
diff --git a/simple-ipc.h b/simple-ipc.h
index dc3606e30bd6..2c48a5ee0047 100644
--- a/simple-ipc.h
+++ b/simple-ipc.h
@@ -5,10 +5,6 @@
  * 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"

base-commit: bf949ade81106fbda068c1fdb2c6fd1cb1babe7e
-- 
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