[Minios-devel] [UNIKRAFT/LWIP PATCH] sockets.c: Make select() not return errors when using it with file descriptor types other than sockets

[Costin Lupu <costin.lupu@xxxxxxxxx>]

lwip's select() implementation supports only sockets. Up until now, we returned
errors when using select() with other file descriptor types. These changes make
it possible to use other file descriptor types as well, even though we won't
receive any notifications for those.

Signed-off-by: Costin Lupu <costin.lupu@xxxxxxxxx>
---
 Config.uk | 10 ++++++++++
 sockets.c | 24 ++++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/Config.uk b/Config.uk
index 92df4d3..8f501fc 100644
--- a/Config.uk
+++ b/Config.uk
@@ -162,6 +162,16 @@ config LWIP_SOCKET
        depends on LWIP_THREADS && (LWIP_UDP || LWIP_TCP)
        default y
 
+if LWIP_SOCKET
+       config LWIP_SOCKET_SELECT_GENERIC_FDS
+               bool "Use select() with any file descriptor type"
+               default y
+               help
+                       lwip's select() implementation supports only sockets. 
This
+                       configuration option makes it possible to use other 
file descriptor
+                       types as well, even though they are not supported by 
lwip.
+endif
+
 menuconfig LWIP_DEBUG
        bool "Debug messages"
        default n
diff --git a/sockets.c b/sockets.c
index cd84b97..c2cf57f 100644
--- a/sockets.c
+++ b/sockets.c
@@ -497,12 +497,20 @@ int select(int nfds, fd_set *readfds, fd_set *writefds, 
fd_set *exceptfds,
                if (readfds && FD_ISSET(i, readfds)) {
                        file = sock_net_file_get(i);
                        if (PTRISERR(file)) {
+#if CONFIG_LWIP_SOCKET_SELECT_GENERIC_FDS
+                               /* We allow other fd types, but we don't 
support them */
+                               if (PTR2ERR(file) == -EBADF) {
+                                       FD_CLR(i, readfds);
+                                       continue;
+                               }
+#else
                                LWIP_DEBUGF(SOCKETS_DEBUG,
                                            ("failed to identify socket 
descriptor\n"));
                                ret = -1;
                                /* Setting the errno */
                                SOCK_NET_SET_ERRNO(PTR2ERR(file));
                                goto EXIT;
+#endif
                        }
                        if (maxfd < file->sock_fd)
                                maxfd = file->sock_fd;
@@ -512,12 +520,20 @@ int select(int nfds, fd_set *readfds, fd_set *writefds, 
fd_set *exceptfds,
                if (writefds && FD_ISSET(i, writefds)) {
                        file = sock_net_file_get(i);
                        if (PTRISERR(file)) {
+#if CONFIG_LWIP_SOCKET_SELECT_GENERIC_FDS
+                               /* We allow other fd types, but we don't 
support them */
+                               if (PTR2ERR(file) == -EBADF) {
+                                       FD_CLR(i, writefds);
+                                       continue;
+                               }
+#else
                                LWIP_DEBUGF(SOCKETS_DEBUG,
                                            ("failed to identify socket 
descriptor\n"));
                                ret = -1;
                                /* Setting the errno */
                                SOCK_NET_SET_ERRNO(PTR2ERR(file));
                                goto EXIT;
+#endif
                        }
                        if (maxfd < file->sock_fd)
                                maxfd = file->sock_fd;
@@ -527,12 +543,20 @@ int select(int nfds, fd_set *readfds, fd_set *writefds, 
fd_set *exceptfds,
                if (exceptfds && FD_ISSET(i, exceptfds)) {
                        file = sock_net_file_get(i);
                        if (PTRISERR(file)) {
+#if CONFIG_LWIP_SOCKET_SELECT_GENERIC_FDS
+                               /* We allow other fd types, but we don't 
support them */
+                               if (PTR2ERR(file) == -EBADF) {
+                                       FD_CLR(i, exceptfds);
+                                       continue;
+                               }
+#else
                                LWIP_DEBUGF(SOCKETS_DEBUG,
                                            ("failed to identify socket 
descriptor\n"));
                                ret = -1;
                                /* Setting the errno */
                                SOCK_NET_SET_ERRNO(PTR2ERR(file));
                                goto EXIT;
+#endif
                        }
                        if (maxfd < file->sock_fd)
                                maxfd = file->sock_fd;
-- 
2.20.1


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