[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>

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 1c2b16f..a0f682c 100644 (file)
--- 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 34f333b..9570718 100644 (file)
--- 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 2744ca8..5030b2b 100644 (file)
--- 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 fdfdab0..9ccb7f4 100644 (file)
--- 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 1c0efc3..1b25d4c 100644 (file)
--- 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 8cbcd60..c8fe880 100644 (file)
--- 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 bf49ab8..fc52103 100644 (file)
--- 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 aecc80a..2cd4929 100644 (file)
--- 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 160258a..bcaf9f1 100644 (file)
--- 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 43b7acf..9e0e700 100644 (file)
--- 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 c4b69c4..0fb8843 100644 (file)
--- 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 a000f1f..70881f8 100644 (file)
--- 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 1c1da86..20e4d03 100644 (file)
--- 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 edd2054..9c7d126 100644 (file)
--- 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 e90a5ca..6f7f65a 100644 (file)
--- 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 52f95b9..dbca9b3 100644 (file)
--- 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 a420d14..3a6cbad 100644 (file)
--- 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 3ddcc64..26f13fb 100644 (file)
--- 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 31b611a..ab6b0d1 100644 (file)
--- 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 0369562..c10176c 100644 (file)
--- 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 c43cbba..c0475a9 100644 (file)
--- 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 dffe447..6fd9477 100644 (file)
--- 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 fb031fe..469eda0 100644 (file)
--- 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 b8ce6bf..aecddcc 100644 (file)
--- 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 d4b293e..1ff7328 100644 (file)
--- 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 4b0272c..19ea5c0 100644 (file)
--- 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 0ea947e..b6e4b89 100644 (file)
--- 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 2b4cc2e..d901465 100644 (file)
--- 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) ||