[Swan-dev] [libreswan/libreswan] Multiple compile errors with gcc (GCC) 7.1.1 20170528 (#104)

[Antony Antony]

On Wed, Jun 14, 2017 at 10:25:07AM -0400, Paul Wouters wrote:
> On Wed, 14 Jun 2017, Timon Giese wrote:
> 
> > I am getting the same errors trying to compile using gcc 7.1.1 20170516 and it gradually gets worse when I try to ignore the
> > warnings mentioned by abique. Next comes a pointer-compare error:
> > 
> > libreswan-3.20/programs/pluto/plutoalg.c: In function ‘aalg_getbyname_ike’:
> > libreswan-3.20/programs/pluto/plutoalg.c:79:25: error: comparison between pointer and zero character constant [-Werror=pointer-c
> > ompare]
> >   if (str == NULL || str == '\0')
> >                          ^~
>

before aalg_getbyname_ike was removed there was a fix for the above issue. 
https://github.com/libreswan/libreswan/commit/c65a002a7b4eb0aa1407c2759e1c721634c739c1
 
for Wimplicit-fallthrough=3 complaince 
I have a patch sitting around when I played with F26. It is attached here to test.
It could be applied, I haven't double checked it yet.

I used F26 gcc version 7.1.1 20170503 (Red Hat 7.1.1-1) (GCC)

> The function aalg_getbyname_ike() no longer exists.
> 
> > In the end i could successfully compile with -Wno-error and -Werror=implicit-fallthrough=0 but it feels wrong...
> 
> We have a number of fallthrough cases. We always mark them with
> 
> 	/* FALL THROUGH */
> 
> to indicate it is intentional. If there is a gcc7 marker for that, we
> could use it. Looking around, I find:
> 
> https://developers.redhat.com/blog/2017/03/10/wimplicit-fallthrough-in-gcc-7/
> 
> and:
> 
> https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html
> 
> Which seems to indicate that -Wimplicit-fallthrough=3 might do the right
> thing, and our comments should match the regular expression.
> 
> If you find a fallthrough that would not have a matching comment, it is
> a bug and we have to look at it and either fix the code or add the
> comment. 
> I don't have a gcc7 system I can easilly test this on.
> 
> Paul
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> Swan-dev at lists.libreswan.org
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-------------- next part --------------
>From 7e58ea548e33081e19643801f85d5781e7ea0435 Mon Sep 17 00:00:00 2001
From: Antony Antony <antony at phenome.org>
Date: Wed, 10 May 2017 19:29:19 +0200
Subject: [PATCH] building: fix -Wimplicit-fallthrough=3 warning for gcc 7.x

Details on -Wimplicit-fallthrough
https://developers.redhat.com/blog/2017/03/10/wimplicit-fallthrough-in-gcc-7/
---
 linux/net/ipsec/pfkey_v2_parse.c | 1 +
 programs/eroute/eroute.c         | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/linux/net/ipsec/pfkey_v2_parse.c b/linux/net/ipsec/pfkey_v2_parse.c
index 363a5d6..247cd21 100644
--- a/linux/net/ipsec/pfkey_v2_parse.c
+++ b/linux/net/ipsec/pfkey_v2_parse.c
@@ -1302,6 +1302,7 @@ int pfkey_msg_parse(struct sadb_msg *pfkey_msg,
 				  pfkey_v2_sadb_type_string(pfkey_msg->
 							    sadb_msg_type));
 		}
+		/* FALLTHROUGH */
 	case K_SADB_ACQUIRE:
 	case K_SADB_REGISTER:
 	case K_SADB_EXPIRE:
diff --git a/programs/eroute/eroute.c b/programs/eroute/eroute.c
index fc9ec42..2b987b4 100644
--- a/programs/eroute/eroute.c
+++ b/programs/eroute/eroute.c
@@ -914,6 +914,7 @@ sa_build:
 				fprintf(stderr, "Mask not found.\n");
 				break;
 			}
+			/* FALLTHROUGH */
 		case EFAULT:
 			if ((action_type == EMT_SETEROUTE) ||
 			    (action_type == EMT_REPLACEROUTE)) {
@@ -924,6 +925,7 @@ sa_build:
 				fprintf(stderr, "Address not found.\n");
 				break;
 			}
+			/* FALLTHROUGH */
 		case EACCES:
 			fprintf(stderr, "access denied.  ");
 			if (getuid() == 0)
-- 
2.9.4