[Chicken-hackers] [PATCH] EGAIN

[Felix]

The attached patch handles EAGAIN in I/O operations the same way as
EWOULDBLOCK (it reschedules the operation). Before, EAGAIN was treated
as an error. This may be a possible fix for part of the problems
reported in #858.


cheers,
felix

>From e007540f8e521618411e850569d21f6a48531ed4 Mon Sep 17 00:00:00 2001
From: felix <address@hidden>
Date: Tue, 12 Jun 2012 10:01:41 +0200
Subject: [PATCH] handle EAGAIN in I/O operations

---
 posixunix.scm |   10 ++++++----
 tcp.scm       |    8 ++++++--
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/posixunix.scm b/posixunix.scm
index 76a0349..1839061 100644
--- a/posixunix.scm
+++ b/posixunix.scm
@@ -1294,7 +1294,8 @@ EOF
             (lambda ()
               (let ((res (##sys#file-select-one fd)))
                 (if (fx= -1 res)
-                    (if (fx= _errno _ewouldblock)
+                    (if (or (fx= _errno _ewouldblock)
+                            (rx= _errno _eagain))
                         #f
                         (posix-error #:file-error loc "cannot select" fd nam))
                     (fx= 1 res))))]
@@ -1310,7 +1311,7 @@ EOF
                   (let ([cnt (##core#inline "C_read" fd buf bufsiz)])
                     (cond ((fx= cnt -1)
                            (select _errno
-                             ((_ewouldblock)
+                             ((_ewouldblock _egain)
                               (##sys#thread-block-for-i/o! 
##sys#current-thread fd #:input)
                               (##sys#thread-yield!)
                               (loop) )
@@ -1326,7 +1327,8 @@ EOF
                                  (loop) )
                                (let ([cnt (##core#inline "C_read" fd buf 
bufsiz)])
                                  (when (fx= cnt -1)
-                                   (if (fx= _errno _ewouldblock)
+                                   (if (or (fx= _errno _ewouldblock)
+                                           (fx= _errno _eagain))
                                        (set! cnt 0)
                                        (posix-error #:file-error loc "cannot 
read" fd nam) ) )
                                  (set! buflen cnt)
@@ -1423,7 +1425,7 @@ EOF
                  (let ([cnt (##core#inline "C_write" fd str len)])
                    (cond ((fx= -1 cnt)
                           (select _errno
-                            ((_ewouldblock)
+                            ((_ewouldblock _eagain)
                              (##sys#thread-yield!)
                              (poke str len) )
                             ((_eintr)
diff --git a/tcp.scm b/tcp.scm
index 0d49c22..b9cbec1 100644
--- a/tcp.scm
+++ b/tcp.scm
@@ -45,6 +45,7 @@
 static WSADATA wsa;
 # define fcntl(a, b, c)  0
 # define EWOULDBLOCK     0
+# define EAGAIN          0
 # define EINPROGRESS     0
 # define typecorrect_getsockopt(socket, level, optname, optval, optlen)        
\
     getsockopt(socket, level, optname, (char *)optval, optlen)
@@ -99,6 +100,7 @@ EOF
 (define-foreign-variable _ipproto_tcp int "IPPROTO_TCP")
 (define-foreign-variable _invalid_socket int "INVALID_SOCKET")
 (define-foreign-variable _ewouldblock int "EWOULDBLOCK")
+(define-foreign-variable _eagain int "EAGAIN")
 (define-foreign-variable _eintr int "EINTR")
 (define-foreign-variable _einprogress int "EINPROGRESS")
 
@@ -348,7 +350,8 @@ EOF
                (let loop ()
                  (let ((n (##net#recv fd buf +input-buffer-size+ 0)))
                    (cond ((eq? -1 n)
-                          (cond ((eq? errno _ewouldblock) 
+                          (cond ((or (eq? errno _ewouldblock) 
+                                     (eq? errno _eagain))
                                  (when tmr
                                    (##sys#thread-block-for-timeout! 
                                     ##sys#current-thread
@@ -465,7 +468,8 @@ EOF
                  (let* ((count (fxmin +output-chunk-size+ len))
                         (n (##net#send fd s offset count 0)) )
                    (cond ((eq? -1 n)
-                          (cond ((eq? errno _ewouldblock)
+                          (cond ((or (eq? errno _ewouldblock)
+                                     (eq? errno _eagain))
                                  (when tmw
                                    (##sys#thread-block-for-timeout! 
                                     ##sys#current-thread
-- 
1.6.0.4