[PATCH 7/8] epoll: Better handling of number of epoll types

[David Gibson <david@gibson.dropbear.id.au>]

As we already did for flow types, use an "EPOLL_NUM_TYPES" isntead of
EPOLL_TYPE_MAX, which is a little bit safer and clearer.  Add a static
assert on the size of the matching names array.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 passt.c | 4 +++-
 passt.h | 4 ++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/passt.c b/passt.c
index 870064f..a37a2f4 100644
--- a/passt.c
+++ b/passt.c
@@ -59,7 +59,7 @@
 
 char pkt_buf[PKT_BUF_BYTES]	__attribute__ ((aligned(PAGE_SIZE)));
 
-char *epoll_type_str[EPOLL_TYPE_MAX + 1] = {
+char *epoll_type_str[] = {
 	[EPOLL_TYPE_TCP]	= "connected TCP socket",
 	[EPOLL_TYPE_TCP_LISTEN]	= "listening TCP socket",
 	[EPOLL_TYPE_TCP_TIMER]	= "TCP timer",
@@ -71,6 +71,8 @@ char *epoll_type_str[EPOLL_TYPE_MAX + 1] = {
 	[EPOLL_TYPE_TAP_PASST]	= "connected qemu socket",
 	[EPOLL_TYPE_TAP_LISTEN]	= "listening qemu socket",
 };
+static_assert(ARRAY_SIZE(epoll_type_str) == EPOLL_NUM_TYPES,
+	      "epoll_type_str[] doesn't match enum epoll_type");
 
 /**
  * post_handler() - Run periodic and deferred tasks for L4 protocol handlers
diff --git a/passt.h b/passt.h
index 20528d5..188ad2c 100644
--- a/passt.h
+++ b/passt.h
@@ -70,7 +70,7 @@ enum epoll_type {
 	/* socket listening for qemu socket connections */
 	EPOLL_TYPE_TAP_LISTEN,
 
-	EPOLL_TYPE_MAX = EPOLL_TYPE_TAP_LISTEN,
+	EPOLL_NUM_TYPES,
 };
 
 /**
@@ -115,7 +115,7 @@ extern char pkt_buf		[PKT_BUF_BYTES];
 
 extern char *epoll_type_str[];
 #define EPOLL_TYPE_STR(n)						\
-	(((uint8_t)(n) <= EPOLL_TYPE_MAX && epoll_type_str[(n)]) ?	\
+	(((uint8_t)(n) < EPOLL_NUM_TYPES && epoll_type_str[(n)]) ?	\
 	                                    epoll_type_str[(n)] : "?")
 
 #include <resolv.h>	/* For MAXNS below */
-- 
@@ -70,7 +70,7 @@ enum epoll_type {
 	/* socket listening for qemu socket connections */
 	EPOLL_TYPE_TAP_LISTEN,
 
-	EPOLL_TYPE_MAX = EPOLL_TYPE_TAP_LISTEN,
+	EPOLL_NUM_TYPES,
 };
 
 /**
@@ -115,7 +115,7 @@ extern char pkt_buf		[PKT_BUF_BYTES];
 
 extern char *epoll_type_str[];
 #define EPOLL_TYPE_STR(n)						\
-	(((uint8_t)(n) <= EPOLL_TYPE_MAX && epoll_type_str[(n)]) ?	\
+	(((uint8_t)(n) < EPOLL_NUM_TYPES && epoll_type_str[(n)]) ?	\
 	                                    epoll_type_str[(n)] : "?")
 
 #include <resolv.h>	/* For MAXNS below */
-- 
2.43.0