From 1b8234e3425e518f40e00751cd0e5261649c166e Mon Sep 17 00:00:00 2001
From: Paul LeoNerd Evans <leonerd@leonerd.org.uk>
Date: Thu, 25 Aug 2011 10:48:41 +0100
Subject: [PATCH] Provide a flag to return RES_ERROR even on signal (EINTR);
 without it, retry the operation

---
 termkey.c                | 14 ++++++++++++--
 termkey.h.in             |  3 ++-
 termkey_advisereadable.3 |  2 +-
 termkey_new.3            |  3 +++
 termkey_waitkey.3.sh     |  2 +-
 5 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/termkey.c b/termkey.c
index dd1020b..921bb6c 100644
--- a/termkey.c
+++ b/termkey.c
@@ -841,12 +841,17 @@ TermKeyResult termkey_waitkey(TermKey *tk, TermKeyKey *key)
 
           struct pollfd fd;
 
+retry:
           fd.fd = tk->fd;
           fd.events = POLLIN;
 
           int pollret = poll(&fd, 1, tk->waittime);
-          if(pollret == -1)
+          if(pollret == -1) {
+            if(errno == EINTR && !(tk->flags & TERMKEY_FLAG_EINTR))
+              goto retry;
+
             return TERMKEY_RES_ERROR;
+          }
 
           if(fd.revents & (POLLIN|POLLHUP|POLLERR))
             ret = termkey_advisereadable(tk);
@@ -884,11 +889,16 @@ void termkey_pushinput(TermKey *tk, const unsigned char *input, size_t inputlen)
 TermKeyResult termkey_advisereadable(TermKey *tk)
 {
   unsigned char buffer[64]; // Smaller than the default size
-  ssize_t len = read(tk->fd, buffer, sizeof buffer);
+  ssize_t len;
+
+retry:
+  len = read(tk->fd, buffer, sizeof buffer);
 
   if(len == -1) {
     if(errno == EAGAIN)
       return TERMKEY_RES_NONE;
+    else if(errno == EINTR && !(tk->flags & TERMKEY_FLAG_EINTR))
+      goto retry;
     else
       return TERMKEY_RES_ERROR;
   }
diff --git a/termkey.h.in b/termkey.h.in
index 33360d8..a22ce5f 100644
--- a/termkey.h.in
+++ b/termkey.h.in
@@ -145,7 +145,8 @@ enum {
   TERMKEY_FLAG_UTF8        = 1 << 3, // Input is definitely UTF-8
   TERMKEY_FLAG_NOTERMIOS   = 1 << 4, // Do not make initial termios calls on construction
   TERMKEY_FLAG_SPACESYMBOL = 1 << 5, // Space is symbolic rather than Unicode
-  TERMKEY_FLAG_CTRLC       = 1 << 6  // Allow Ctrl-C to be read as normal, disabling SIGINT
+  TERMKEY_FLAG_CTRLC       = 1 << 6, // Allow Ctrl-C to be read as normal, disabling SIGINT
+  TERMKEY_FLAG_EINTR       = 1 << 7  // Return ERROR on signal (EINTR) rather than retry
 };
 
 void termkey_check_version(int major, int minor);
diff --git a/termkey_advisereadable.3 b/termkey_advisereadable.3
index ba859ca..fe70125 100644
--- a/termkey_advisereadable.3
+++ b/termkey_advisereadable.3
@@ -25,7 +25,7 @@ At least one byte was read.
 No nore bytes were read.
 .TP
 .B TERMKEY_RES_ERROR
-An IO error occured. \fIerrno\fP will be preserved.
+An IO error occured. \fIerrno\fP will be preserved. If the error is \fBEINTR\fP then this will only be returned if \fBTERMKEY_FLAG_EINTR\fP flag is not set; if it is then the IO operation will be retried instead.
 .SH "SEE ALSO"
 .BR termkey_new (3),
 .BR termkey_getkey (3),
diff --git a/termkey_new.3 b/termkey_new.3
index 3cb24ce..7cf307a 100644
--- a/termkey_new.3
+++ b/termkey_new.3
@@ -42,6 +42,9 @@ Report space as being a symbolic key rather than a Unicode codepoint.
 .TP
 .B TERMKEY_FLAG_CTRLC
 Disable the \fBSIGINT\fP behaviour of \fICtrl-C\fP. If this flag is provided, then \fICtrl-C\fP will be available as a normal keypress, rather than sending the process group a \fBSIGINT\fP. This flag only takes effect without \fBTERMKEY_FLAG_NOTERMIOS\fP; with it, none of the signal keys are disabled anyway.
+.TP
+.B TERMKEY_FLAG_EINTR
+Without this flag, IO operations are retried when interrupted by a signal (\fBEINTR\fP). With this flag the \fBTERMKEY_RES_ERROR\fP result is returned instead.
 .PP
 When the constructor is invoked, it attempts to detect if the current locale is UTF-8 aware or not, and sets either the \fBTERMKEY_FLAG_UTF8\fP or \fBTERMKEY_FLAG_RAW\fP flag. One of these two bits will always be in effect. The current flags in effect can be obtained by \fBtermkey_get_flags\fP(3).
 .SH VERSION CHECK MACRO
diff --git a/termkey_waitkey.3.sh b/termkey_waitkey.3.sh
index 81d9f6e..ee8edaf 100644
--- a/termkey_waitkey.3.sh
+++ b/termkey_waitkey.3.sh
@@ -27,7 +27,7 @@ A key event as been provided.
 No key events are ready and the terminal has been closed, so no more will arrive.
 .TP
 .B TERMKEY_RES_ERROR
-An IO error occured. \fIerrno\fP will be preserved.
+An IO error occured. \fIerrno\fP will be preserved. If the error is \fBEINTR\fP then this will only be returned if \fBTERMKEY_FLAG_EINTR\fP flag is not set; if it is then the IO operation will be retried instead.
 .SH EXAMPLE
 The following example program prints details of every keypress until the user presses "Ctrl-C".
 .PP