- (dtucker) [channels.c configure.ac serverloop.c] Bug #1102: Around AIX

   4.3.3 ML3 or so, the AIX pty layer starting passing zero-length writes
   on the pty slave as zero-length reads on the pty master, which sshd
   interprets as the descriptor closing.  Since most things don't do zero
   length writes this rarely matters, but occasionally it happens, and when
   it does the SSH pty session appears to hang, so we add a special case for
   this condition.  ok djm@

1 files changed, 10 insertions, 0 deletions

diff --git a/serverloop.c b/serverloop.c
index 021ba68c..c1eb2885 100644
--- a/serverloop.c
+++ b/serverloop.c
@@ -387,10 +387,15 @@ process_input(fd_set *readset)
 
 	/* Read and buffer any available stdout data from the program. */
 	if (!fdout_eof && FD_ISSET(fdout, readset)) {
+		errno = 0;
 		len = read(fdout, buf, sizeof(buf));
 		if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
 			/* do nothing */
+#ifdef PTY_ZEROREAD
 		} else if (len <= 0) {
+#else
+		} else if (len < 0 || (len == 0 && errno != 0)) {
+#endif
 			fdout_eof = 1;
 		} else {
 			buffer_append(&stdout_buffer, buf, len);
@@ -399,10 +404,15 @@ process_input(fd_set *readset)
 	}
 	/* Read and buffer any available stderr data from the program. */
 	if (!fderr_eof && FD_ISSET(fderr, readset)) {
+		errno = 0;
 		len = read(fderr, buf, sizeof(buf));
 		if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
 			/* do nothing */
+#ifdef PTY_ZEROREAD
 		} else if (len <= 0) {
+#else
+		} else if (len < 0 || (len == 0 && errno != 0)) {
+#endif
 			fderr_eof = 1;
 		} else {
 			buffer_append(&stderr_buffer, buf, len);