Acme crashes on AIX 7.3

[bhuntsman]

When running Acme on AIX 7.3, the window briefly flashes on the screen, then disappears, and the following message is printed to the terminal:

acme: can't post service: Restart the system call

This occurs on AIX 7.3, and possibly 7.2 though I haven't tested it on 7.2. This was also tested with a working build on AIX 7.1 and copied to a 7.3 system and the same behavior observed.

The error is generated from src/cmd/acme/fsys.c:127

Though it is hard to tell where the "Restart the system call" return value is coming from.

This appears to be an issue related to timing and possibly threads. If the program is run under the debugger with a breakpoint set in post9pservice, and the post9pservice call is single-stepped through, the window eventually gets displayed and then works. Further debugging assistance would be greatly appreciated.

[bhuntsman]

This definitely looks like a timing issue on AIX 7.3. The following patch resolves the issue:

diff --git a/src/lib9/post9p.c b/src/lib9/post9p.c
index e894ef9e..93710cbd 100644
--- a/src/lib9/post9p.c
+++ b/src/lib9/post9p.c
@@ -41,6 +41,7 @@ post9pservice(int fd, char *name, char *mtpt)
                }
                close(fd);
                w = waitfor(pid);
+               sleep(10);
                if(w == nil)
                        return -1;
                if(w->msg && w->msg[0]){

However, I'm not sure that's the best way to go. On the other hand it shouldn't hurt.