add xembed wrapper utility

xembed will cause a command to attempt to XEmbed into the window given
by the environment variable XEMBED, so long as it is in the foreground
of its controlling terminal. This causes a process to effectively take
the place of the terminal window, unless it is backgrounded.

Signed-off-by: Christoph Lohmann <20h@r-36.net>

LICENSE

@@ -1,8 +1,8 @@
 MIT/X Consortium License
 
 © 2009-2011 Enno Boland <g s01 de>
-© 2011 Connor Lane Smith <cls@lubutu.com>
-© 2012-2014 Christoph Lohmann <20h@r-36.net>
+© 2011,2015 Connor Lane Smith <cls@lubutu.com>
+© 2012-2015 Christoph Lohmann <20h@r-36.net>
 
 Permission is hereby granted, free of charge, to any person obtaining a
 copy of this software and associated documentation files (the "Software"),

Makefile

@@ -3,10 +3,11 @@
 
 include config.mk
 
-SRC = tabbed.c
+SRC = tabbed.c xembed.c
 OBJ = ${SRC:.c=.o}
+BIN = ${OBJ:.o=}
 
-all: options tabbed
+all: options ${BIN}
 
 options:
 	@echo tabbed build options:
@@ -24,13 +25,13 @@ config.h:
 	@echo creating $@ from config.def.h
 	@cp config.def.h $@
 
-tabbed: tabbed.o
+.o:
 	@echo CC -o $@
-	@${CC} -o $@ tabbed.o ${LDFLAGS}
+	@${CC} -o $@ $< ${LDFLAGS}
 
 clean:
 	@echo cleaning
-	@rm -f tabbed ${OBJ} tabbed-${VERSION}.tar.gz
+	@rm -f ${BIN} ${OBJ} tabbed-${VERSION}.tar.gz
 
 dist: clean
 	@echo creating dist tarball
@@ -42,19 +43,23 @@ dist: clean
 	@rm -rf tabbed-${VERSION}
 
 install: all
-	@echo installing executable file to ${DESTDIR}${PREFIX}/bin
+	@echo installing executable files to ${DESTDIR}${PREFIX}/bin
 	@mkdir -p ${DESTDIR}${PREFIX}/bin
-	@cp -f tabbed ${DESTDIR}${PREFIX}/bin
+	@cp -f ${BIN} ${DESTDIR}${PREFIX}/bin
 	@chmod 755 ${DESTDIR}${PREFIX}/bin/tabbed
-	@echo installing manual page to ${DESTDIR}${MANPREFIX}/man1
+	@echo installing manual pages to ${DESTDIR}${MANPREFIX}/man1
 	@mkdir -p ${DESTDIR}${MANPREFIX}/man1
 	@sed "s/VERSION/${VERSION}/g" < tabbed.1 > ${DESTDIR}${MANPREFIX}/man1/tabbed.1
 	@chmod 644 ${DESTDIR}${MANPREFIX}/man1/tabbed.1
+	@sed "s/VERSION/${VERSION}/g" < xembed.1 > ${DESTDIR}${MANPREFIX}/man1/xembed.1
+	@chmod 644 ${DESTDIR}${MANPREFIX}/man1/xembed.1
 
 uninstall:
-	@echo removing executable file from ${DESTDIR}${PREFIX}/bin
+	@echo removing executable files from ${DESTDIR}${PREFIX}/bin
 	@rm -f ${DESTDIR}${PREFIX}/bin/tabbed
-	@echo removing manual page from ${DESTDIR}${MANPREFIX}/man1
+	@rm -f ${DESTDIR}${PREFIX}/bin/xembed
+	@echo removing manual pages from ${DESTDIR}${MANPREFIX}/man1
 	@rm -f ${DESTDIR}${MANPREFIX}/man1/tabbed.1
+	@rm -f ${DESTDIR}${MANPREFIX}/man1/xembed.1
 
 .PHONY: all options clean dist install uninstall

tabbed.1

@@ -156,7 +156,7 @@ See the LICENSE file for the authors.
 .SH LICENSE
 See the LICENSE file for the terms of redistribution.
 .SH SEE ALSO
-.BR st (1)
+.BR st (1),
+.BR xembed (1)
 .SH BUGS
 Please report them.
-

xembed.1

@@ -0,0 +1,35 @@
+.TH XEMBED 1 tabbed\-VERSION
+.SH NAME
+xembed \- XEmbed foreground process
+.SH SYNOPSIS
+.B xembed
+.I flag command
+.RI [ "argument ..." ]
+.SH DESCRIPTION
+If the environment variable XEMBED is set, and
+.B xembed
+is in the foreground of its controlling tty, it will execute
+.IP
+command flag $XEMBED [argument ...]
+.LP
+Otherwise it will execute
+.IP
+command [argument ...]
+.LP
+.SH EXAMPLE
+In a terminal emulator within a
+.B tabbed
+session, the shell alias
+.IP
+$ alias surf='xembed -e surf'
+.LP
+will cause `surf' to open in a new tab, unless it is run in the background,
+i.e. `surf &', in which case it will instead open in a new window.
+.SH AUTHORS
+See the LICENSE file for the authors.
+.SH LICENSE
+See the LICENSE file for the terms of redistribution.
+.SH SEE ALSO
+.BR tabbed (1)
+.SH BUGS
+Please report them.

xembed.c

@@ -0,0 +1,46 @@
+/*
+ * See LICENSE file for copyright and license details.
+ */
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+int
+main(int argc, char **argv)
+{
+	char *xembed;
+	int tty;
+	pid_t pgrp, tcpgrp;
+
+	if(argc < 3) {
+		fprintf(stderr, "usage: %s flag cmd ...\n", argv[0]);
+		return 2;
+	}
+
+	if(!(xembed = getenv("XEMBED")))
+		goto noembed;
+
+	if((tty = open("/dev/tty", O_RDONLY)) < 0)
+		goto noembed;
+
+	pgrp = getpgrp();
+	tcpgrp = tcgetpgrp(tty);
+
+	close(tty);
+
+	if(pgrp == tcpgrp) { /* in foreground of tty */
+		argv[0] = argv[2];
+		argv[2] = xembed;
+	}
+	else {
+noembed:
+		argv += 2;
+	}
+
+	execvp(argv[0], argv);
+
+	perror(argv[0]); /* failed to execute */
+	return 1;
+}