Improve handling of lost terminals

When feh loses its controlling terminal at runtime, e.g. due to backgrounding /
disowning, it will no longer issue a warning on each terminal keystroke.

3 files changed, 38 insertions, 21 deletions

diff --git a/src/feh.h b/src/feh.h
index fb9fefe..a4a0a7b 100644
--- a/src/feh.h
+++ b/src/feh.h
@@ -141,6 +141,8 @@ char *slideshow_create_name(feh_file * file, winwidget winwid);
 char *thumbnail_create_name(feh_file * file, winwidget winwid);
 void init_keyevents(void);
 void init_buttonbindings(void);
+void setup_stdin(void);
+void restore_stdin(void);
 void feh_event_handle_keypress(XEvent * ev);
 void feh_event_handle_stdin();
 void feh_event_handle_generic(winwidget winwid, unsigned int state, KeySym keysym, unsigned int button);
@@ -201,6 +203,6 @@ extern char *mode;		/* label for the current mode */
 /* to terminate long-running children with SIGALRM */
 extern int childpid;
 
-extern int control_via_stdin;
+extern unsigned char control_via_stdin;
 
 #endif
diff --git a/src/keyevents.c b/src/keyevents.c
index a6833a6..14f1a14 100644
--- a/src/keyevents.c
+++ b/src/keyevents.c
@@ -29,8 +29,36 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include "filelist.h"
 #include "winwidget.h"
 #include "options.h"
+#include <termios.h>
 
 fehkb keys;
+struct termios old_term_settings;
+unsigned char control_via_stdin = 0;
+
+void setup_stdin() {
+	struct termios ctrl;
+
+	control_via_stdin = 1;
+
+	if (tcgetattr(STDIN_FILENO, &old_term_settings) == -1)
+		eprintf("tcgetattr failed");
+	if (tcgetattr(STDIN_FILENO, &ctrl) == -1)
+		eprintf("tcgetattr failed");
+
+	ctrl.c_iflag &= ~(PARMRK | ISTRIP
+			| INLCR | IGNCR | IXON);
+	ctrl.c_lflag &= ~(ECHO | ICANON | IEXTEN);
+	ctrl.c_cflag &= ~(CSIZE | PARENB);
+	ctrl.c_cflag |= CS8;
+
+	if (tcsetattr(STDIN_FILENO, TCSANOW, &ctrl) == -1)
+		eprintf("tcsetattr failed");
+}
+
+void restore_stdin() {
+	if (tcsetattr(STDIN_FILENO, TCSANOW, &old_term_settings) == -1)
+		eprintf("tcsetattr failed");
+}
 
 static void feh_set_kb(fehkey *key, unsigned int s0, unsigned int y0, unsigned
 		int s1, unsigned int y1, unsigned int s2, unsigned int y2) {
@@ -274,8 +302,11 @@ void feh_event_handle_stdin()
 	char stdin_buf[2];
 	KeySym keysym = NoSymbol;
 	if (read(STDIN_FILENO, &stdin_buf, 1) == -1) {
-		if (control_via_stdin)
-			weprintf("reading a command from stdin failed");
+		control_via_stdin = 0;
+		if (isatty(STDIN_FILENO) && getpgrp() == (tcgetpgrp(STDIN_FILENO))) {
+			weprintf("reading a command from stdin failed - disabling control via stdin");
+			restore_stdin();
+		}
 		return;
 	}
 	stdin_buf[1] = '\0';
diff --git a/src/main.c b/src/main.c
index bb4dec4..605c113 100644
--- a/src/main.c
+++ b/src/main.c
@@ -38,9 +38,6 @@ char **cmdargv = NULL;
 int cmdargc = 0;
 char *mode = NULL;
 
-struct termios old_term_settings;
-int control_via_stdin = 0;
-
 int main(int argc, char **argv)
 {
 	atexit(feh_clean_exit);
@@ -122,19 +119,7 @@ int feh_main_iteration(int block)
 		 *   also don't get input from stdin anyway.
 		 */
 		if (isatty(STDIN_FILENO) && !opt.multiwindow && getpgrp() == (tcgetpgrp(STDIN_FILENO))) {
-			control_via_stdin = 1;
-			struct termios ctrl;
-			if (tcgetattr(STDIN_FILENO, &old_term_settings) == -1)
-				eprintf("tcgetattr failed");
-			if (tcgetattr(STDIN_FILENO, &ctrl) == -1)
-				eprintf("tcgetattr failed");
-			ctrl.c_iflag &= ~(PARMRK | ISTRIP
-					| INLCR | IGNCR | IXON);
-			ctrl.c_lflag &= ~(ECHO | ICANON | IEXTEN);
-			ctrl.c_cflag &= ~(CSIZE | PARENB);
-			ctrl.c_cflag |= CS8;
-			if (tcsetattr(STDIN_FILENO, TCSANOW, &ctrl) == -1)
-				eprintf("tcsetattr failed");
+			setup_stdin();
 		}
 	}
 
@@ -243,8 +228,7 @@ void feh_clean_exit(void)
 	 *   around with it) <https://github.com/derf/feh/issues/324>
 	 */
 	if (control_via_stdin && isatty(STDIN_FILENO) && getpgrp() == (tcgetpgrp(STDIN_FILENO)))
-		if (tcsetattr(STDIN_FILENO, TCSANOW, &old_term_settings) == -1)
-			eprintf("tcsetattr failed");
+		restore_stdin();
 
 	if (opt.filelistfile)
 		feh_write_filelist(filelist, opt.filelistfile);