*/
#ifndef lint
-static const char rcsid[] = "$Id: os_unix.c,v 1.7 1999/02/05 04:08:56 roberts Exp $";
+static const char rcsid[] = "$Id: os_unix.c,v 1.8 1999/02/06 05:08:33 roberts Exp $";
#endif /* not lint */
#include "fcgimisc.h"
}
\f
+/**********************************************************************
+ * Determine if the errno resulting from a failed accept() warrants a
+ * retry or exit(). Based on Apache's http_main.c accept() handling
+ * and Stevens' Unix Network Programming Vol 1, 2nd Ed, para. 15.6.
+ */
+static int is_reasonable_accept_errno (const int error)
+{
+ switch (error) {
+#ifdef EPROTO
+ /* EPROTO on certain older kernels really means ECONNABORTED, so
+ * we need to ignore it for them. See discussion in new-httpd
+ * archives nh.9701 search for EPROTO. Also see nh.9603, search
+ * for EPROTO: There is potentially a bug in Solaris 2.x x<6, and
+ * other boxes that implement tcp sockets in userland (i.e. on top of
+ * STREAMS). On these systems, EPROTO can actually result in a fatal
+ * loop. See PR#981 for example. It's hard to handle both uses of
+ * EPROTO. */
+ case EPROTO:
+#endif
+#ifdef ECONNABORTED
+ case ECONNABORTED:
+#endif
+ /* Linux generates the rest of these, other tcp stacks (i.e.
+ * bsd) tend to hide them behind getsockopt() interfaces. They
+ * occur when the net goes sour or the client disconnects after the
+ * three-way handshake has been done in the kernel but before
+ * userland has picked up the socket. */
+#ifdef ECONNRESET
+ case ECONNRESET:
+#endif
+#ifdef ETIMEDOUT
+ case ETIMEDOUT:
+#endif
+#ifdef EHOSTUNREACH
+ case EHOSTUNREACH:
+#endif
+#ifdef ENETUNREACH
+ case ENETUNREACH:
+#endif
+ return 1;
+
+ default:
+ return 0;
+ }
+}
+
+/**********************************************************************
+ * This works around a problem on Linux 2.0.x and SCO Unixware (maybe
+ * others?). When a connect() is made to a Unix Domain socket, but its
+ * not accept()ed before the web server gets impatient and close()s, an
+ * accept() results in a valid file descriptor, but no data to read.
+ * This causes a block on the first read() - which never returns!
+ *
+ * Another approach to this is to write() to the socket to provoke a
+ * SIGPIPE, but this is a pain because of the FastCGI protocol, the fact
+ * that whatever is written has to be universally ignored by all FastCGI
+ * web servers, and a SIGPIPE handler has to be installed which returns
+ * (or SIGPIPE is ignored).
+ *
+ * READABLE_UNIX_FD_DROP_DEAD_TIMEVAL = 2,0 by default.
+ *
+ * Making it shorter is probably safe, but I'll leave that to you. Making
+ * it 0,0 doesn't work reliably. The shorter you can reliably make it,
+ * the faster your application will be able to recover (waiting 2 seconds
+ * may _cause_ the problem when there is a very high demand). At any rate,
+ * this is better than perma-blocking.
+ */
+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);
+
+ return select(fd + 1, &read_fds, NULL, NULL, &tval) >= 0 && FD_ISSET(fd, &read_fds);
+}
+
/*
*----------------------------------------------------------------------
*
int OS_FcgiIpcAccept(char *clientAddrList)
{
int socket;
- union u_sockaddr {
+ union {
struct sockaddr_un un;
struct sockaddr_in in;
} sa;
int len;
#endif
- if (AcquireLock(TRUE) < 0) {
- return (-1);
- }
- for (;;) {
- do {
- len = sizeof(sa);
- socket = accept(FCGI_LISTENSOCK_FILENO,
- (struct sockaddr *) &sa.un, &len);
- } while ((socket < 0) && (errno == EINTR));
-
- if (socket >= 0) {
-
- if (sa.in.sin_family == AF_INET) {
-#ifdef TCP_NODELAY
- /* No replies to outgoing data, so disable Nagle algorithm */
- int set = 1;
- setsockopt(socket, IPPROTO_TCP, TCP_NODELAY,
- (char *)&set, sizeof(set));
-#endif
-
- /* Check that the client IP address is OK */
- if (ClientAddrOK(&sa.in, clientAddrList))
- break;
- }
- else {
- /* This works around a problem on Linux 2.0.x and
- * SCO Unixware (maybe others?). When a connect() is made to
- * a Unix Domain socket, but its not accept()ed before the
- * web server gets impatient and close()s, an accept()
- * here results in a valid file descriptor, but no data to
- * read. This causes a block on the first read() - and
- * never returns!
- *
- * Another approach to this is to write()
- * to the socket to provoke a SIGPIPE, but this is a pain
- * because of the FastCGI protocol, the fact that whatever
- * is written has to be universally ignored by all FastCGI
- * web servers, and a SIGPIPE handler has to be installed
- * which returns (or SIGPIPE is ignored).
- *
- * READABLE_UNIX_FD_DROP_DEAD_TIMEVAL = 2,0 by default.
- *
- * Making it shorter is probably safe, but I'll leave that
- * to you. Making it 0,0 doesn't work reliably. The
- * shorter you can reliably make it, the faster your
- * application will be able to recover (waiting 2 seconds
- * may _cause_ the problem when there is a very high demand).
- * At any rate, this is better than perma-blocking. */
-
- struct timeval tval = { READABLE_UNIX_FD_DROP_DEAD_TIMEVAL };
- fd_set read_fds;
-
- FD_ZERO(&read_fds);
- FD_SET(socket, &read_fds);
- if (select(socket + 1, &read_fds, NULL, NULL, &tval) > 0
- && FD_ISSET(socket, &read_fds))
- {
- break;
- }
- }
-
- close(socket);
- continue;
- }
+ while (1) {
+ if (AcquireLock(TRUE) < 0)
+ return (-1);
- /* Based on Apache's (v1.3.1) http_main.c accept() handling and
- * Stevens' Unix Network Programming Vol 1, 2nd Ed, para. 15.6
- */
- switch (errno) {
-#ifdef EPROTO
- /* EPROTO on certain older kernels really means
- * ECONNABORTED, so we need to ignore it for them.
- * See discussion in new-httpd archives nh.9701
- * search for EPROTO.
- *
- * Also see nh.9603, search for EPROTO:
- * There is potentially a bug in Solaris 2.x x<6,
- * and other boxes that implement tcp sockets in
- * userland (i.e. on top of STREAMS). On these
- * systems, EPROTO can actually result in a fatal
- * loop. See PR#981 for example. It's hard to
- * handle both uses of EPROTO.
- */
- case EPROTO:
-#endif
-#ifdef ECONNABORTED
- case ECONNABORTED:
-#endif
- /* Linux generates the rest of these, other tcp
- * stacks (i.e. bsd) tend to hide them behind
- * getsockopt() interfaces. They occur when
- * the net goes sour or the client disconnects
- * after the three-way handshake has been done
- * in the kernel but before userland has picked
- * up the socket.
- */
-#ifdef ECONNRESET
- case ECONNRESET:
-#endif
-#ifdef ETIMEDOUT
- case ETIMEDOUT:
-#endif
-#ifdef EHOSTUNREACH
- case EHOSTUNREACH:
-#endif
-#ifdef ENETUNREACH
- case ENETUNREACH:
-#endif
- break; /* switch(errno) */
+ while (1) {
+ do {
+ len = sizeof(sa);
+ socket = accept(FCGI_LISTENSOCK_FILENO, (struct sockaddr *) &sa.un, &len);
+ } while (socket < 0 && errno == EINTR);
- default: {
+ if (socket < 0) {
+ if (!is_reasonable_accept_errno(errno)) {
int errnoSave = errno;
+
ReleaseLock();
errno = errnoSave;
+ return (-1);
}
- return (-1);
- } /* switch(errno) */
- } /* for(;;) */
+ errno = 0;
+ }
+ else {
+ int set = 1;
+
+ if (sa.in.sin_family != AF_INET)
+ break;
+
+#ifdef TCP_NODELAY
+ /* No replies to outgoing data, so disable Nagle */
+ setsockopt(socket, IPPROTO_TCP, TCP_NODELAY, (char *)&set, sizeof(set));
+#endif
+
+ /* Check that the client IP address is approved */
+ if (ClientAddrOK(&sa.in, clientAddrList))
+ break;
+
+ close(socket);
+ }
+ } /* while(1) - accept */
+
+ if (ReleaseLock() < 0)
+ return (-1);
+
+ if (sa.in.sin_family != AF_UNIX || is_af_unix_keeper(socket))
+ break;
+
+ close(socket);
+ } /* while(1) - lock */
- if (ReleaseLock() < 0) {
- return (-1);
- }
return (socket);
}
\f
projects / catagits/fcgi2.git / commitdiff