configure --with-rsh=CMD and default blocking-IO support

[Wayne Davison]

A while back I argued for adding a --with-rsh=CMD option to configure
and got some general agreement that it would be a good thing (especially
for systems that don't have rsh at all).  However, the changes were
never integrated into rsync.

This patch adds the --with-rsh=CMD option to configure and modifies
main.c to improve the blocking-IO setting code.  The old code would set
blocking_io to '1' if the string matched either "rsh" or "remsh"
(whichever one was configured into rsync).  The new code has a slightly
modified version of this check (that still works even if RSYNC_RSH isn't
defined to be "rsh"), but it also adds a way to force the blocking-IO
setting (both at configure time and via the RSYNC_RSH environment
variable).  The idiom I chose to use was to prefix the value with '@' to
indicate that blocking-IO should be used, and to prefix it with "@@" to
indicate that blocking-IO should not be used.  This allows the installer
to specify --with-rsh=@@ssh to explicitly specify non-blocking-IO for
ssh (for the paranoid), the user to specify RSYNC_RSH=@/local/bin/rsh to
get blocking-IO when using a path to rsh (which the old code would force
the user to specify the --blocking-io option), and also to be able to
specify --with-rsh=@@rsh to get a non-blocking-IO rsh by default (which
is impossible with the old code without specifying a path).

I've appended the patch to the end.  Don't forget to run autoconf after
applying it.

..wayne..

---8<------8<------8<------8<---cut here--->8------>8------>8------>8---
Index: rsync/config.h.in
--- rsync/config.h.in	15 Jan 2002 09:53:29 -0000	1.68
+++ rsync/config.h.in	30 Jan 2002 18:45:18 -0000
@@ -303,6 +303,9 @@
 #undef RETSIGTYPE

 /* */
+#undef RSYNC_RSH
+
+/* */
 #undef RSYNC_PATH

 /* rsync release version */
Index: rsync/configure.in
--- rsync/configure.in	25 Jan 2002 23:19:21 -0000	1.130
+++ rsync/configure.in	30 Jan 2002 18:45:19 -0000
@@ -78,6 +78,10 @@
 AC_ARG_WITH(included-popt,
         [  --with-included-popt    use bundled popt library, not from system])

+AC_ARG_WITH(rsh,
+	[  --with-rsh=CMD          set rsh command to CMD (default: \"remsh\" or \"rsh\")],
+	[ AC_DEFINE_UNQUOTED(RSYNC_RSH, "$with_rsh", [ ]) ])
+
 AC_ARG_WITH(rsync-path,
 	[  --with-rsync-path=PATH  set default --rsync-path to PATH (default: \"rsync\")],
 	[ RSYNC_PATH="$with_rsync_path" ],
Index: rsync/main.c
--- rsync/main.c	25 Jan 2002 10:07:41 -0000	1.138
+++ rsync/main.c	30 Jan 2002 18:45:22 -0000
@@ -209,8 +209,19 @@

 		server_options(args,&argc);

-
-		if (strcmp(cmd, RSYNC_RSH) == 0) blocking_io = 1;
+		if (*cmd == '@') {
+			if (*++cmd == '@') {
+				cmd++;
+				blocking_io = 0;
+			} else
+				blocking_io = 1;
+			args[0] = cmd;
+		} else if (strcmp(cmd, "rsh") == 0
+#if HAVE_REMSH
+			|| strcmp(cmd, "remsh") == 0
+#endif
+		    )
+			blocking_io = 1;
 	}

 	args[argc++] = ".";
Index: rsync/rsync.h
--- rsync/rsync.h	25 Jan 2002 23:00:21 -0000	1.121
+++ rsync/rsync.h	30 Jan 2002 18:45:29 -0000
@@ -85,10 +85,12 @@

 #include "config.h"

+#ifndef RSYNC_RSH
 #if HAVE_REMSH
 #define RSYNC_RSH "remsh"
 #else
 #define RSYNC_RSH "rsh"
+#endif
 #endif

 #include <sys/types.h>
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