GTK: implemented --detach|-d option for detaching from controlling terminalmaster-fmsbw-ci

This is useful to launch from a terminal without "blocking" this terminal.
There are tools like nohup and daemonize (BSD) to do the same, but having it
builtin is shorter to write.

4 files changed, 40 insertions, 10 deletions

diff --git a/TODO b/TODO
index e613582..720cc6d 100644
--- a/TODO
+++ b/TODO
@@ -781,14 +781,6 @@ Features:
    in multi-line command lines.
    This would be tricky to do in Gtk, though since we're currently using
    an overlay.
- * GTK: gsciteco --detach|-d to detach from the running terminal
-   (ie. daemonize).
-   Will help to occupy less tabs in the terminal emulator.
-   In most shells you can type `gsciteco &>/dev/null & disown`, but having
-   a shortcut probably makes sense.
-   On FreeBSD you could also `daemonize /usr/local/bin/gsciteco`.
-   There is --xembed but there are no stable terminal emulators
-   with Xembed support.
  * <EB> could create directories on demand and clean them up on rubout.
    Unless additional files appeared in the meantime, in which case we should
    output a warning.
diff --git a/configure.ac b/configure.ac
index c0e9939..31fd8fb 100644
--- a/configure.ac
+++ b/configure.ac
@@ -213,7 +213,9 @@ AC_CHECK_FUNCS([memset setlocale strchr strrchr fstat sscanf], , [
 # glib defines G_OS_UNIX instead...
 case $host in
 *-*-linux* | *-*-*bsd* | *-*-darwin* | *-*-cygwin* | *-*-haiku*)
-	AC_CHECK_FUNCS([realpath readlink pathconf fchown dup dup2 getpid open read kill mmap popen pclose isatty], , [
+	# NOTE: Keep this on a single line for compatibility
+	# with ancient versions of Autoconf.
+	AC_CHECK_FUNCS([realpath readlink pathconf fchown dup dup2 getpid open read kill mmap popen pclose isatty fork setsid], , [
 		AC_MSG_ERROR([Missing libc function])
 	])
 	AC_SEARCH_LIBS(dladdr, [dl], , [
diff --git a/src/interface-gtk/interface.c b/src/interface-gtk/interface.c
index a86e3fd..32370d9 100644
--- a/src/interface-gtk/interface.c
+++ b/src/interface-gtk/interface.c
@@ -19,6 +19,7 @@
 #include "config.h"
 #endif
 
+#include <stdlib.h>
 #include <string.h>
 #include <signal.h>
 
@@ -27,6 +28,7 @@
 #include <glib/gstdio.h>
 
 #ifdef G_OS_UNIX
+#include <unistd.h>
 #include <glib-unix.h>
 #endif
 
@@ -105,7 +107,7 @@ static struct {
 	/* current document's name or empty string for "(Unnamed)" buffer */
 	teco_string_t info_current;
 
-	gboolean no_csd;
+	gboolean no_csd, detach;
 	gint xembed_id;
 
 	GtkWidget *info_bar_widget;
@@ -132,6 +134,26 @@ static struct {
 void
 teco_interface_init(void)
 {
+#ifdef G_OS_UNIX
+	if (teco_interface.detach) {
+		/*
+		 * NOTE: There is also daemon() on BSD/Linux,
+		 * but the following should be more portable.
+		 */
+		pid_t pid = fork();
+		g_assert(pid >= 0);
+		if (pid != 0)
+			/* parent process */
+			exit(EXIT_SUCCESS);
+
+		setsid();
+
+		g_freopen("/dev/null", "r", stdin);
+		g_freopen("/dev/null", "a+", stdout);
+		g_freopen("/dev/null", "a+", stderr);
+	}
+#endif
+
 	/*
 	 * gtk_init() is not necessary when using gtk_get_option_group(),
 	 * but this will open the default display.
@@ -341,6 +363,11 @@ teco_interface_get_options(void)
 		 G_OPTION_ARG_INT, &teco_interface.xembed_id,
 		 "Embed into an existing X11 Window.", "ID"},
 #endif
+#ifdef G_OS_UNIX
+		{"detach", 'd', G_OPTION_FLAG_IN_MAIN,
+		 G_OPTION_ARG_NONE, &teco_interface.detach,
+		 "Detach from controlling terminal (daemonize).", NULL},
+#endif
 		{NULL}
 	};
 
diff --git a/tests/testsuite.at b/tests/testsuite.at
index a360840..09c4df2 100644
--- a/tests/testsuite.at
+++ b/tests/testsuite.at
@@ -460,6 +460,15 @@ AT_CHECK([[$SCITECO -e "@EI'^EQ[\$SCITECOPATH]/opener.tes' M[opener] EF .-11\"N(
 AT_CHECK([[$SCITECO -e "@EI'^EQ[\$SCITECOPATH]/opener.tes' M[opener] EF EJ-2\"N(0/0)'" -S +1 data.123]], 0, ignore, ignore)
 AT_CLEANUP
 
+AT_BANNER([Program features])
+
+AT_SETUP([Detaching from terminal])
+AT_SKIP_IF([$SCITECO --help | $GREP -qvz '\-\-detach'])
+AT_CHECK([$SCITECO --detach -e '23= @EW/test.txt/' && sleep 1], 0, [], [])
+# FIXME: What if the "daemon" takes longer than 1 second to write test.txt?
+AT_FAIL_IF([! test -f test.txt])
+AT_CLEANUP
+
 AT_BANNER([Regression Tests])
 
 AT_SETUP([Glob patterns with character classes])