LD_PRELOAD poll implementation

- add poll implementation
- implementation based on vppcom_poll
- implementation based on vppcom_select
- currently vppcom_select implementation is picked

Change-Id: If6c2862ae72e9969335aca5b8085957c98287dc0
Signed-off-by: shrinivasan ganapathy <shrinivasanganapathy@gmail.com>
Signed-off-by: Dave Wallace <dwallacelf@gmail.com>

extras/vcl-ldpreload/src/libvcl-ldpreload/vcom.h

@@ -178,6 +178,12 @@ extern int
 vcom_epoll_pwait (int __epfd, struct epoll_event *__events,
 		  int __maxevents, int __timeout, const __sigset_t * __ss);
 
+/*
+ * NOTE: observed __nfds is less than 128 from kubecon strace files
+ * for the POC, it's fair to assume that nfds is less than 1024.
+ * TBD: make it thread safe and design to scale.
+ * */
+#define MAX_POLL_NFDS_DEFAULT   1024
 extern int vcom_poll (struct pollfd *__fds, nfds_t __nfds, int __timeout);
 
 #ifdef __USE_GNU

extras/vcl-ldpreload/src/libvcl-ldpreload/vcom_glibc_socket.h

@@ -23,6 +23,8 @@
 #include <fcntl.h>
 
 #include <sys/epoll.h>
+
+#include <signal.h>
 #include <poll.h>
 
 /*

extras/vcl-ldpreload/src/libvcl-ldpreload/vcom_socket.h

@@ -448,6 +448,17 @@ vcom_socket_epoll_pwait (int __epfd, struct epoll_event *__events,
 			 int __maxevents, int __timeout,
 			 const __sigset_t * __ss);
 
+/*
+ * handle only vcom fds
+ */
+int vcom_socket_poll (struct pollfd *__fds, nfds_t __nfds, int __timeout);
+
+#ifdef __USE_GNU
+int
+vcom_socket_ppoll (struct pollfd *__fds, nfds_t __nfds,
+		   const struct timespec *__timeout, const __sigset_t * __ss);
+#endif
+
 #endif /* included_vcom_socket_h */
 
 /*

extras/vcl-ldpreload/src/libvcl-ldpreload/vcom_socket_wrapper.c

@@ -263,6 +263,15 @@ typedef int (*__libc_epoll_pwait) (int __epfd, struct epoll_event * __events,
 				   int __maxevents, int __timeout,
 				   const __sigset_t * __ss);
 
+typedef int (*__libc_poll) (struct pollfd * __fds, nfds_t __nfds,
+			    int __timeout);
+
+#ifdef __USE_GNU
+typedef int (*__libc_ppoll) (struct pollfd * __fds, nfds_t __nfds,
+			     const struct timespec * __timeout,
+			     const __sigset_t * __ss);
+#endif
+
 
 #define SWRAP_SYMBOL_ENTRY(i) \
         union { \
@@ -334,6 +343,10 @@ struct swrap_libc_symbols
   SWRAP_SYMBOL_ENTRY (epoll_ctl);
   SWRAP_SYMBOL_ENTRY (epoll_wait);
   SWRAP_SYMBOL_ENTRY (epoll_pwait);
+  SWRAP_SYMBOL_ENTRY (poll);
+#ifdef __USE_GNU
+  SWRAP_SYMBOL_ENTRY (ppoll);
+#endif
 };
 
 struct swrap
@@ -811,6 +824,25 @@ libc_epoll_pwait (int __epfd, struct epoll_event *__events,
 						 __ss);
 }
 
+int
+libc_poll (struct pollfd *__fds, nfds_t __nfds, int __timeout)
+{
+  swrap_bind_symbol_libc (poll);
+
+  return swrap.libc.symbols._libc_poll.f (__fds, __nfds, __timeout);
+}
+
+#ifdef __USE_GNU
+int
+libc_ppoll (struct pollfd *__fds, nfds_t __nfds,
+	    const struct timespec *__timeout, const __sigset_t * __ss)
+{
+  swrap_bind_symbol_libc (ppoll);
+
+  return swrap.libc.symbols._libc_ppoll.f (__fds, __nfds, __timeout, __ss);
+}
+#endif
+
 static void
 swrap_thread_prepare (void)
 {

extras/vcl-ldpreload/src/libvcl-ldpreload/vcom_socket_wrapper.h

@@ -63,6 +63,7 @@
 #include <sys/ioctl.h>
 #include <sys/select.h>
 #include <sys/epoll.h>
+#include <poll.h>
 #include <sys/uio.h>
 #include <stdlib.h>
 
@@ -212,6 +213,13 @@ int libc_epoll_pwait (int __epfd, struct epoll_event *__events,
 		      int __maxevents, int __timeout,
 		      const __sigset_t * __ss);
 
+int libc_poll (struct pollfd *__fds, nfds_t __nfds, int __timeout);
+
+#ifdef __USE_GNU
+int libc_ppoll (struct pollfd *__fds, nfds_t __nfds,
+		const struct timespec *__timeout, const __sigset_t * __ss);
+#endif
+
 void swrap_constructor (void);
 
 void swrap_destructor (void);