[PATCH] POLLRDHUP/EPOLLRDHUP handling for half-closed devices notifications

Implement the half-closed devices notifiation, by adding a new POLLRDHUP
(and its alias EPOLLRDHUP) bit to the existing poll/select sets.  Since the
existing POLLHUP handling, that does not report correctly half-closed
devices, was feared to be changed, this implementation leaves the current
POLLHUP reporting unchanged and simply add a new bit that is set in the few
places where it makes sense.  The same thing was discussed and conceptually
agreed quite some time ago:

http://lkml.org/lkml/2003/7/12/116

Since this new event bit is added to the existing Linux poll infrastruture,
even the existing poll/select system calls will be able to use it.  As far
as the existing POLLHUP handling, the patch leaves it as is.  The
pollrdhup-2.6.16.rc5-0.10.diff defines the POLLRDHUP for all the existing
archs and sets the bit in the six relevant files.  The other attached diff
is the simple change required to sys/epoll.h to add the EPOLLRDHUP
definition.

There is "a stupid program" to test POLLRDHUP delivery here:

 http://www.xmailserver.org/pollrdhup-test.c

It tests poll(2), but since the delivery is same epoll(2) will work equally.

Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

28 files changed, 35 insertions, 4 deletions

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 1c2b16fda13a..a0f682cdd03e 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -599,7 +599,7 @@ sys_epoll_ctl(int epfd, int op, int fd, struct epoll_event __user *event)
         switch (op) {
         case EPOLL_CTL_ADD:
                 if (!epi) {
-                        epds.events |= POLLERR | POLLHUP;
+                        epds.events |= POLLERR | POLLHUP | POLLRDHUP;
 
                         error = ep_insert(ep, &epds, tfile, fd);
                 } else
@@ -613,7 +613,7 @@ sys_epoll_ctl(int epfd, int op, int fd, struct epoll_event __user *event)
                 break;
         case EPOLL_CTL_MOD:
                 if (epi) {
-                        epds.events |= POLLERR | POLLHUP;
+                        epds.events |= POLLERR | POLLHUP | POLLRDHUP;
                         error = ep_modify(ep, epi, &epds);
                 } else
                         error = -ENOENT;
diff --git a/include/asm-alpha/poll.h b/include/asm-alpha/poll.h
index 34f333b762a0..95707182b3ed 100644
--- a/include/asm-alpha/poll.h
+++ b/include/asm-alpha/poll.h
@@ -13,6 +13,8 @@
 #define POLLWRBAND      (1 << 9)
 #define POLLMSG         (1 << 10)
 #define POLLREMOVE      (1 << 11)
+#define POLLRDHUP       (1 << 12)
+
 
 struct pollfd {
         int fd;
diff --git a/include/asm-arm/poll.h b/include/asm-arm/poll.h
index 2744ca831f5d..5030b2b232a3 100644
--- a/include/asm-arm/poll.h
+++ b/include/asm-arm/poll.h
@@ -16,6 +16,7 @@
 #define POLLWRBAND      0x0200
 #define POLLMSG         0x0400
 #define POLLREMOVE      0x1000
+#define POLLRDHUP       0x2000
 
 struct pollfd {
         int fd;
diff --git a/include/asm-arm26/poll.h b/include/asm-arm26/poll.h
index fdfdab064a65..9ccb7f4190ca 100644
--- a/include/asm-arm26/poll.h
+++ b/include/asm-arm26/poll.h
@@ -15,6 +15,7 @@
 #define POLLWRNORM      0x0100
 #define POLLWRBAND      0x0200
 #define POLLMSG         0x0400
+#define POLLRDHUP       0x2000
 
 struct pollfd {
         int fd;
diff --git a/include/asm-cris/poll.h b/include/asm-cris/poll.h
index 1c0efc3e4be7..1b25d4cf498c 100644
--- a/include/asm-cris/poll.h
+++ b/include/asm-cris/poll.h
@@ -15,6 +15,7 @@
 #define POLLWRBAND      512
 #define POLLMSG         1024
 #define POLLREMOVE      4096
+#define POLLRDHUP       8192
 
 struct pollfd {
         int fd;
diff --git a/include/asm-frv/poll.h b/include/asm-frv/poll.h
index 8cbcd60e334f..c8fe8801d075 100644
--- a/include/asm-frv/poll.h
+++ b/include/asm-frv/poll.h
@@ -12,6 +12,7 @@
 #define POLLRDBAND      128
 #define POLLWRBAND      256
 #define POLLMSG         0x0400
+#define POLLRDHUP       0x2000
 
 struct pollfd {
         int fd;
diff --git a/include/asm-h8300/poll.h b/include/asm-h8300/poll.h
index bf49ab8ad6da..fc52103b276a 100644
--- a/include/asm-h8300/poll.h
+++ b/include/asm-h8300/poll.h
@@ -12,6 +12,7 @@
 #define POLLRDBAND      128
 #define POLLWRBAND      256
 #define POLLMSG         0x0400
+#define POLLRDHUP       0x2000
 
 struct pollfd {
         int fd;
diff --git a/include/asm-i386/poll.h b/include/asm-i386/poll.h
index aecc80a15d36..2cd4929abd40 100644
--- a/include/asm-i386/poll.h
+++ b/include/asm-i386/poll.h
@@ -16,6 +16,7 @@
 #define POLLWRBAND      0x0200
 #define POLLMSG         0x0400
 #define POLLREMOVE      0x1000
+#define POLLRDHUP       0x2000
 
 struct pollfd {
         int fd;
diff --git a/include/asm-ia64/poll.h b/include/asm-ia64/poll.h
index 160258a0528d..bcaf9f140242 100644
--- a/include/asm-ia64/poll.h
+++ b/include/asm-ia64/poll.h
@@ -21,6 +21,7 @@
 #define POLLWRBAND      0x0200
 #define POLLMSG         0x0400
 #define POLLREMOVE      0x1000
+#define POLLRDHUP       0x2000
 
 struct pollfd {
         int fd;
diff --git a/include/asm-m32r/poll.h b/include/asm-m32r/poll.h
index 43b7acf732d5..9e0e700e727c 100644
--- a/include/asm-m32r/poll.h
+++ b/include/asm-m32r/poll.h
@@ -21,6 +21,7 @@
 #define POLLWRBAND      0x0200
 #define POLLMSG         0x0400
 #define POLLREMOVE      0x1000
+#define POLLRDHUP       0x2000
 
 struct pollfd {
         int fd;
diff --git a/include/asm-m68k/poll.h b/include/asm-m68k/poll.h
index c4b69c4a87e1..0fb8843647f8 100644
--- a/include/asm-m68k/poll.h
+++ b/include/asm-m68k/poll.h
@@ -13,6 +13,7 @@
 #define POLLWRBAND      256
 #define POLLMSG         0x0400
 #define POLLREMOVE      0x1000
+#define POLLRDHUP       0x2000
 
 struct pollfd {
         int fd;
diff --git a/include/asm-mips/poll.h b/include/asm-mips/poll.h
index a000f1f789e3..70881f8c5c50 100644
--- a/include/asm-mips/poll.h
+++ b/include/asm-mips/poll.h
@@ -17,6 +17,7 @@
 /* These seem to be more or less nonstandard ...  */
 #define POLLMSG         0x0400
 #define POLLREMOVE      0x1000
+#define POLLRDHUP       0x2000
 
 struct pollfd {
         int fd;
diff --git a/include/asm-parisc/poll.h b/include/asm-parisc/poll.h
index 1c1da86934cf..20e4d03c74cb 100644
--- a/include/asm-parisc/poll.h
+++ b/include/asm-parisc/poll.h
@@ -16,6 +16,7 @@
 #define POLLWRBAND      0x0200
 #define POLLMSG         0x0400
 #define POLLREMOVE      0x1000
+#define POLLRDHUP       0x2000
 
 struct pollfd {
         int fd;
diff --git a/include/asm-powerpc/poll.h b/include/asm-powerpc/poll.h
index edd2054da86b..9c7d12631033 100644
--- a/include/asm-powerpc/poll.h
+++ b/include/asm-powerpc/poll.h
@@ -13,6 +13,7 @@
 #define POLLWRBAND      0x0200
 #define POLLMSG         0x0400
 #define POLLREMOVE      0x1000
+#define POLLRDHUP       0x2000
 
 struct pollfd {
         int fd;
diff --git a/include/asm-s390/poll.h b/include/asm-s390/poll.h
index e90a5ca42061..6f7f65ac7d27 100644
--- a/include/asm-s390/poll.h
+++ b/include/asm-s390/poll.h
@@ -24,6 +24,7 @@
 #define POLLWRBAND      0x0200
 #define POLLMSG         0x0400
 #define POLLREMOVE      0x1000
+#define POLLRDHUP       0x2000
 
 struct pollfd {
         int fd;
diff --git a/include/asm-sh/poll.h b/include/asm-sh/poll.h
index 52f95b9188dc..dbca9b32f4a6 100644
--- a/include/asm-sh/poll.h
+++ b/include/asm-sh/poll.h
@@ -16,6 +16,7 @@
 #define POLLWRBAND      0x0200
 #define POLLMSG         0x0400
 #define POLLREMOVE      0x1000
+#define POLLRDHUP       0x2000
 
 struct pollfd {
         int fd;
diff --git a/include/asm-sh64/poll.h b/include/asm-sh64/poll.h
index a420d14eb704..3a6cbad08d28 100644
--- a/include/asm-sh64/poll.h
+++ b/include/asm-sh64/poll.h
@@ -26,6 +26,7 @@
 #define POLLWRNORM      0x0100
 #define POLLWRBAND      0x0200
 #define POLLMSG         0x0400
+#define POLLRDHUP       0x2000
 
 struct pollfd {
         int fd;
diff --git a/include/asm-sparc/poll.h b/include/asm-sparc/poll.h
index 3ddcc6481f09..26f13fb35497 100644
--- a/include/asm-sparc/poll.h
+++ b/include/asm-sparc/poll.h
@@ -13,6 +13,7 @@
 #define POLLWRBAND      256
 #define POLLMSG         512
 #define POLLREMOVE      1024
+#define POLLRDHUP       2048
 
 struct pollfd {
         int fd;
diff --git a/include/asm-sparc64/poll.h b/include/asm-sparc64/poll.h
index 31b611aa7468..ab6b0d1bb4ad 100644
--- a/include/asm-sparc64/poll.h
+++ b/include/asm-sparc64/poll.h
@@ -13,6 +13,7 @@
 #define POLLWRBAND      256
 #define POLLMSG         512
 #define POLLREMOVE      1024
+#define POLLRDHUP       2048
 
 struct pollfd {
         int fd;
diff --git a/include/asm-v850/poll.h b/include/asm-v850/poll.h
index 0369562c7e15..c10176c2c28f 100644
--- a/include/asm-v850/poll.h
+++ b/include/asm-v850/poll.h
@@ -13,6 +13,7 @@
 #define POLLWRBAND      0x0100
 #define POLLMSG         0x0400
 #define POLLREMOVE      0x1000
+#define POLLRDHUP       0x2000
 
 struct pollfd {
         int fd;
diff --git a/include/asm-x86_64/poll.h b/include/asm-x86_64/poll.h
index c43cbba31913..c0475a9d8bb8 100644
--- a/include/asm-x86_64/poll.h
+++ b/include/asm-x86_64/poll.h
@@ -16,6 +16,7 @@
 #define POLLWRBAND      0x0200
 #define POLLMSG         0x0400
 #define POLLREMOVE      0x1000
+#define POLLRDHUP       0x2000
 
 struct pollfd {
         int fd;
diff --git a/include/asm-xtensa/poll.h b/include/asm-xtensa/poll.h
index dffe447534e0..6fd94773e866 100644
--- a/include/asm-xtensa/poll.h
+++ b/include/asm-xtensa/poll.h
@@ -27,6 +27,7 @@
 
 #define POLLMSG         0x0400
 #define POLLREMOVE      0x0800
+#define POLLRDHUP       0x2000
 
 struct pollfd {
         int fd;
diff --git a/net/bluetooth/af_bluetooth.c b/net/bluetooth/af_bluetooth.c
index fb031fe9be9e..469eda0f0dfd 100644
--- a/net/bluetooth/af_bluetooth.c
+++ b/net/bluetooth/af_bluetooth.c
@@ -238,6 +238,9 @@ unsigned int bt_sock_poll(struct file * file, struct socket *sock, poll_table *w
         if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
                 mask |= POLLERR;
 
+        if (sk->sk_shutdown & RCV_SHUTDOWN)
+                mask |= POLLRDHUP;
+
         if (sk->sk_shutdown == SHUTDOWN_MASK)
                 mask |= POLLHUP;
 
diff --git a/net/core/datagram.c b/net/core/datagram.c
index b8ce6bf81188..aecddcc30401 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -500,6 +500,8 @@ unsigned int datagram_poll(struct file *file, struct socket *sock,
         /* exceptional events? */
         if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
                 mask |= POLLERR;
+        if (sk->sk_shutdown & RCV_SHUTDOWN)
+                mask |= POLLRDHUP;
         if (sk->sk_shutdown == SHUTDOWN_MASK)
                 mask |= POLLHUP;
 
diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index d4b293e16283..1ff7328b0e17 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -350,7 +350,7 @@ unsigned int dccp_poll(struct file *file, struct socket *sock,
         if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == DCCP_CLOSED)
                 mask |= POLLHUP;
         if (sk->sk_shutdown & RCV_SHUTDOWN)
-                mask |= POLLIN | POLLRDNORM;
+                mask |= POLLIN | POLLRDNORM | POLLRDHUP;
 
         /* Connected? */
         if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_RESPOND)) {
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 4b0272c92d66..19ea5c0b094b 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -365,7 +365,7 @@ unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
         if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
                 mask |= POLLHUP;
         if (sk->sk_shutdown & RCV_SHUTDOWN)
-                mask |= POLLIN | POLLRDNORM;
+                mask |= POLLIN | POLLRDNORM | POLLRDHUP;
 
         /* Connected? */
         if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 0ea947eb6813..b6e4b89539b3 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4894,6 +4894,8 @@ unsigned int sctp_poll(struct file *file, struct socket *sock, poll_table *wait)
         /* Is there any exceptional events?  */
         if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
                 mask |= POLLERR;
+        if (sk->sk_shutdown & RCV_SHUTDOWN)
+                mask |= POLLRDHUP;
         if (sk->sk_shutdown == SHUTDOWN_MASK)
                 mask |= POLLHUP;
 
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 2b4cc2eea5b3..d901465ce013 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1878,6 +1878,8 @@ static unsigned int unix_poll(struct file * file, struct socket *sock, poll_tabl
                 mask |= POLLERR;
         if (sk->sk_shutdown == SHUTDOWN_MASK)
                 mask |= POLLHUP;
+        if (sk->sk_shutdown & RCV_SHUTDOWN)
+                mask |= POLLRDHUP;
 
         /* readable? */
         if (!skb_queue_empty(&sk->sk_receive_queue) ||