From 08b7f57c980a8a4fefbb838b075ad0c914be1447 Mon Sep 17 00:00:00 2001
From: Joachim Nilsson <troglobit@gmail.com>
Date: Sun, 14 Sep 2014 03:44:20 +0200
Subject: [PATCH] src/sysunix.c: Restart syscalls on spurious EINTR

Handle tcgetattr(), tcsetattr() and ioctl() by wrapping them in
a retry-loop and restarting them when receiving EINTR.

Should fix problem with sporadic error messages on the console
like this one:

     'Failed tcsetattr: Interrupted system call'

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>
---
 src/sysunix.c | 87 +++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 71 insertions(+), 16 deletions(-)

diff --git a/src/sysunix.c b/src/sysunix.c
index 7d38eb7..ab3aaed 100644
--- a/src/sysunix.c
+++ b/src/sysunix.c
@@ -18,20 +18,75 @@
  *    ever read sources, credits must appear in the documentation.
  * 4. This notice may not be removed or altered.
  */
+
+#include <errno.h>
 #include "editline.h"
 
+#ifndef HAVE_TCGETATTR
+/* Wrapper for ioctl syscalls to restart on signal */
+static int ioctl_wrap(int fd, int req, void *arg)
+{
+    int result, retries = 3;
+
+    while (-1 == (result = ioctl(fd, req, arg)) && retries > 0) {
+	retries--;
+
+	if (EINTR == errno)
+	    continue;
+
+	break;
+    }
+
+    return result;
+}
+#endif
+
 /* Prefer termios over the others since it is likely the most portable. */
 #if defined(HAVE_TCGETATTR)
 #include <termios.h>
 
+/* Wrapper for tcgetattr */
+static int getattr(int fd, struct termios *arg)
+{
+    int result, retries = 3;
+
+    while (-1 == (result = tcgetattr(fd, arg)) && retries > 0) {
+	retries--;
+
+	if (EINTR == errno)
+	    continue;
+
+	break;
+    }
+
+    return result;
+}
+
+/* Wrapper for tcgetattr */
+static int setattr(int fd, int opt, const struct termios *arg)
+{
+    int result, retries = 3;
+
+    while (-1 == (result = tcsetattr(fd, opt, arg)) && retries > 0) {
+	retries--;
+
+	if (EINTR == errno)
+	    continue;
+
+	break;
+    }
+
+    return result;
+}
+
 void rl_ttyset(int Reset)
 {
     static struct termios       old;
     struct termios              new;
 
     if (!Reset) {
-        if (-1 == tcgetattr(0, &old))
-	    perror("Failed tcgetattr");
+        if (-1 == getattr(0, &old))
+	    perror("Failed tcgetattr()");
         rl_erase = old.c_cc[VERASE];
         rl_kill = old.c_cc[VKILL];
         rl_eof = old.c_cc[VEOF];
@@ -50,11 +105,11 @@ void rl_ttyset(int Reset)
 	    new.c_iflag &= ~ISTRIP;
         new.c_cc[VMIN] = 1;
         new.c_cc[VTIME] = 0;
-        if (-1 == tcsetattr(0, TCSADRAIN, &new))
-	    perror("Failed tcsetattr");
+        if (-1 == setattr(0, TCSADRAIN, &new))
+	    perror("Failed tcsetattr(TCSADRAIN)");
     } else {
-        if (-1 == tcsetattr(0, TCSADRAIN, &old))
-	    perror("Failed tcsetattr");
+        if (-1 == setattr(0, TCSADRAIN, &old))
+	    perror("Failed tcsetattr(TCSADRAIN)");
     }
 }
 
@@ -67,7 +122,7 @@ void rl_ttyset(int Reset)
     struct termio               new;
 
     if (!Reset) {
-	if (-1 == ioctl(0, TCGETA, &old))
+	if (-1 == ioctl_wrap(0, TCGETA, &old))
 	    perror("Failed ioctl(TCGETA)");
         rl_erase = old.c_cc[VERASE];
         rl_kill = old.c_cc[VKILL];
@@ -88,10 +143,10 @@ void rl_ttyset(int Reset)
 
         new.c_cc[VMIN] = 1;
         new.c_cc[VTIME] = 0;
-        if (-1 == ioctl(0, TCSETAW, &new))
+        if (-1 == ioctl_wrap(0, TCSETAW, &new))
 	    perror("Failed ioctl(TCSETAW)");
     } else {
-	if (-1 == ioctl(0, TCSETAW, &old))
+	if (-1 == ioctl_wrap(0, TCSETAW, &old))
 	    perror("Failed ioctl(TCSETAW)");
     }
 }
@@ -110,19 +165,19 @@ void rl_ttyset(int Reset)
 #endif
 
     if (!Reset) {
-        if (-1 == ioctl(0, TIOCGETP, &old_sgttyb))
+        if (-1 == ioctl_wrap(0, TIOCGETP, &old_sgttyb))
 	    perror("Failed TIOCGETP");
         rl_erase = old_sgttyb.sg_erase;
         rl_kill = old_sgttyb.sg_kill;
 
-        if (-1 == ioctl(0, TIOCGETC, &old_tchars))
+        if (-1 == ioctl_wrap(0, TIOCGETC, &old_tchars))
 	    perror("Failed TIOCGETC");
         rl_eof = old_tchars.t_eofc;
         rl_intr = old_tchars.t_intrc;
         rl_quit = old_tchars.t_quitc;
 
 #ifdef CONFIG_SIGSTOP
-        if (-1 == ioctl(0, TIOCGLTC, &old_ltchars))
+        if (-1 == ioctl_wrap(0, TIOCGLTC, &old_ltchars))
 	    perror("Failed TIOCGLTC");
         rl_susp = old_ltchars.t_suspc;
 #endif
@@ -134,17 +189,17 @@ void rl_ttyset(int Reset)
 	    new_sgttyb.sg_flags &= ~PASS8;
 	else
 	    new_sgttyb.sg_flags |= PASS8;
-        if (-1 == ioctl(0, TIOCSETP, &new_sgttyb))
+        if (-1 == ioctl_wrap(0, TIOCSETP, &new_sgttyb))
 	    perror("Failed TIOCSETP");
         new_tchars = old_tchars;
         new_tchars.t_intrc = -1;
         new_tchars.t_quitc = -1;
-        if (-1 == ioctl(0, TIOCSETC, &new_tchars))
+        if (-1 == ioctl_wrap(0, TIOCSETC, &new_tchars))
 	    perror("Failed TIOCSETC");
     } else {
-        if (-1 == ioctl(0, TIOCSETP, &old_sgttyb))
+        if (-1 == ioctl_wrap(0, TIOCSETP, &old_sgttyb))
 	    perror("Failed TIOCSETP");
-        if (-1 == ioctl(0, TIOCSETC, &old_tchars))
+        if (-1 == ioctl_wrap(0, TIOCSETC, &old_tchars))
 	    perror("Failed TIOCSETC");
     }
 }