Taken from http://pkgs.fedoraproject.org/cgit/rpms/fcgi.git/plain/fcgi-2.4.0-poll.patch
Fixes CVE-2012-6687.

Author: Anton Kortunov <toshic.toshic@gmail.com>
Bug-Ubuntu: https://bugs.launchpad.net/ubuntu/+source/libfcgi/+bug/933417
Description: use poll in os_unix.c instead of select to avoid problem with > 1024 connections
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diff --git a/libfcgi/os_unix.c b/libfcgi/os_unix.c
index 73e6a7f..af35aee 100755
--- a/libfcgi/os_unix.c
+++ b/libfcgi/os_unix.c
@@ -42,6 +42,7 @@ static const char rcsid[] = "$Id: os_unix.c,v 1.37 2002/03/05 19:14:49 robs Exp
 #include <sys/time.h>
 #include <sys/un.h>
 #include <signal.h>
+#include <poll.h>
 
 #ifdef HAVE_NETDB_H
 #include <netdb.h>
@@ -103,6 +104,9 @@ static int volatile maxFd = -1;
 static int shutdownPending = FALSE;
 static int shutdownNow = FALSE;
 
+static int libfcgiOsClosePollTimeout = 2000;
+static int libfcgiIsAfUnixKeeperPollTimeout = 2000;
+
 void OS_ShutdownPending()
 {
     shutdownPending = TRUE;
@@ -168,6 +172,16 @@ int OS_LibInit(int stdioFds[3])
     if(libInitialized)
         return 0;
 
+    char *libfcgiOsClosePollTimeoutStr = getenv( "LIBFCGI_OS_CLOSE_POLL_TIMEOUT" );
+    if(libfcgiOsClosePollTimeoutStr) {
+        libfcgiOsClosePollTimeout = atoi(libfcgiOsClosePollTimeoutStr);
+    }
+
+    char *libfcgiIsAfUnixKeeperPollTimeoutStr = getenv( "LIBFCGI_IS_AF_UNIX_KEEPER_POLL_TIMEOUT" );
+    if(libfcgiIsAfUnixKeeperPollTimeoutStr) {
+        libfcgiIsAfUnixKeeperPollTimeout = atoi(libfcgiIsAfUnixKeeperPollTimeoutStr);
+    }
+
     asyncIoTable = (AioInfo *)malloc(asyncIoTableSize * sizeof(AioInfo));
     if(asyncIoTable == NULL) {
         errno = ENOMEM;
@@ -755,19 +769,16 @@ int OS_Close(int fd)
 
     if (shutdown(fd, 1) == 0)
     {
-        struct timeval tv;
-        fd_set rfds;
+        struct pollfd pfd;
         int rv;
         char trash[1024];
 
-        FD_ZERO(&rfds);
+        pfd.fd = fd;
+        pfd.events = POLLIN;
 
         do 
         {
-            FD_SET(fd, &rfds);
-            tv.tv_sec = 2;
-            tv.tv_usec = 0;
-            rv = select(fd + 1, &rfds, NULL, NULL, &tv);
+            rv = poll(&pfd, 1, libfcgiOsClosePollTimeout);
         }
         while (rv > 0 && read(fd, trash, sizeof(trash)) > 0);
     }
@@ -1116,13 +1127,11 @@ static int is_reasonable_accept_errno (const int error)
  */
 static int is_af_unix_keeper(const int fd)
 {
-    struct timeval tval = { READABLE_UNIX_FD_DROP_DEAD_TIMEVAL };
-    fd_set read_fds;
-
-    FD_ZERO(&read_fds);
-    FD_SET(fd, &read_fds);
+    struct pollfd pfd;
+    pfd.fd = fd;
+    pfd.events = POLLIN;
 
-    return select(fd + 1, &read_fds, NULL, NULL, &tval) >= 0 && FD_ISSET(fd, &read_fds);
+    return poll(&pfd, 1, libfcgiIsAfUnixKeeperPollTimeout) >= 0 && (pfd.revents & POLLIN);
 }
 
 /*
0.)

* guix/gcrypt.scm, guix/hash.scm, guix/pk-crypto.scm,
tests/hash.scm, tests/pk-crypto.scm: Remove.
* configure.ac: Test for Guile-Gcrypt.  Remove LIBGCRYPT and
LIBGCRYPT_LIBDIR assignments.
* m4/guix.m4 (GUIX_ASSERT_LIBGCRYPT_USABLE): Remove.
* README: Add Guile-Gcrypt to the dependencies; move libgcrypt as
"required unless --disable-daemon".
* doc/guix.texi (Requirements): Likewise.
* gnu/packages/bash.scm, guix/derivations.scm, guix/docker.scm,
guix/git.scm, guix/http-client.scm, guix/import/cpan.scm,
guix/import/cran.scm, guix/import/crate.scm, guix/import/elpa.scm,
guix/import/gnu.scm, guix/import/hackage.scm,
guix/import/texlive.scm, guix/import/utils.scm, guix/nar.scm,
guix/pki.scm, guix/scripts/archive.scm,
guix/scripts/authenticate.scm, guix/scripts/download.scm,
guix/scripts/hash.scm, guix/scripts/pack.scm,
guix/scripts/publish.scm, guix/scripts/refresh.scm,
guix/scripts/substitute.scm, guix/store.scm,
guix/store/deduplication.scm, guix/tests.scm, tests/base32.scm,
tests/builders.scm, tests/challenge.scm, tests/cpan.scm,
tests/crate.scm, tests/derivations.scm, tests/gem.scm,
tests/nar.scm, tests/opam.scm, tests/pki.scm,
tests/publish.scm, tests/pypi.scm, tests/store-deduplication.scm,
tests/store.scm, tests/substitute.scm: Adjust imports.
* gnu/system/vm.scm: Likewise.
(guile-sqlite3&amp;co): Rename to...
(gcrypt-sqlite3&amp;co): ... this.  Add GUILE-GCRYPT.
(expression-&gt;derivation-in-linux-vm)[config]: Remove.
(iso9660-image)[config]: Remove.
(qemu-image)[config]: Remove.
(system-docker-image)[config]: Remove.
* guix/scripts/pack.scm: Adjust imports.
(guile-sqlite3&amp;co): Rename to...
(gcrypt-sqlite3&amp;co): ... this.  Add GUILE-GCRYPT.
(self-contained-tarball)[build]: Call 'make-config.scm' without
 #:libgcrypt argument.
(squashfs-image)[libgcrypt]: Remove.
[build]: Call 'make-config.scm' without #:libgcrypt.
(docker-image)[config, json]: Remove.
[build]: Add GUILE-GCRYPT to the extensions  Remove (guix config) from
the imported modules.
* guix/self.scm (specification-&gt;package): Remove "libgcrypt", add
"guile-gcrypt".
(compiled-guix): Remove #:libgcrypt.
[guile-gcrypt]: New variable.
[dependencies]: Add it.
[*core-modules*]: Remove #:libgcrypt from 'make-config.scm' call.
Add #:extensions.
[*config*]: Remove #:libgcrypt from 'make-config.scm' call.
(%dependency-variables): Remove %libgcrypt.
(make-config.scm): Remove #:libgcrypt.
* build-aux/build-self.scm (guile-gcrypt): New variable.
(make-config.scm): Remove #:libgcrypt.
(build-program)[fake-gcrypt-hash]: New variable.
Add (gcrypt hash) to the imported modules.  Adjust load path
assignments.
* gnu/packages/package-management.scm (guix)[propagated-inputs]: Add
GUILE-GCRYPT.
[arguments]: In 'wrap-program' phase, add GUILE-GCRYPT to the search
path.
</span></span></td><td>Ludovic Courtès</td></tr>