Magnus Hagander wrote:
Andrew Dunstan wrote:
I have just discovered that the recently implemented pipe chunking
protocol is broken on Windows. This is because the pipes are operating
in text mode and doing LF->CR-LF translation, so the number of bytes
received is not the number transmitted and set in the protocol header.
I have not yet succeeded in turning this behaviour off (_setmode()
didn't seem to affect it). If we can't find a way to turn it off, the
only solution short of abandoning its use on Windows that I can think of
is to translate LF on input to something unlikely like 0x1C and then
translate it back when we read it from the pipe.
At what point does it actually do the translation? Meaning what
system/library call has it?
Are we using the pipes from src/port/pipe.c? It does sound a bit weird
that they'd do that, since it's basically just emulating stuff over
standard tcp sockets, but perhaps something is broken in that code?
Sorry, haven't really checked up on the chunk code yet, so I don't know
offhand where to look.
It looks like we aren't. In fact. it looks like the only call to
pgpipe() in the whole source tree is in the syslogger and it's in
specifically non-Windows code, meaning that that whole file is currently
useless.
Uh, see port.h, lines 212-224. If you're using the pipe() command to
create it, it's used.
No, it's the other way around :-) If you use pgpipe() on Unix you're
calling pipe():
#ifndef WIN32
/*
* The function prototypes are not supplied because every C file
* includes this file.
*/
#define pgpipe(a) pipe(a)
#define piperead(a,b,c) read(a,b,c)
#define pipewrite(a,b,c) write(a,b,c)
#else
extern int pgpipe(int handles[2]);
extern int piperead(int s, char *buf, int len);
#define pipewrite(a,b,c) send(a,b,c,0)
#define PG_SIGNAL_COUNT 32
#define kill(pid,sig) pgkill(pid,sig)
extern int pgkill(int pid, int sig);
#endif
Maybe you should have a good look at src/backend/postmaster/syslogger.c.
If we could get rid of the pipe-read threads and all the special Windows
cruft there that would certainly be an advance.
I'll try to squeeze some time in to do that - I'll have to read up on
the whole pipe/chunk thing first though, so it'll be a while.
You don't need to understand the protocol (it's a very simple
packetising protocol). The important point is that we have an anonymous
pipe (created with CreatePipe) which has been dup'ed into stderr.
cheers
andrew
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