attempt to deal with the portability fiasco of strnvis(3)

configure

@@ -275,6 +275,7 @@ fi
 HAVE_ENDIAN_H=0
 HAVE_SYS_ENDIAN_H=0
 HAVE_MACHINE_ENDIAN=0
+HAVE_BROKEN_STRNVIS=0
 
 runtest endian_h	ENDIAN_H	|| \
 runtest sys_endian_h	SYS_ENDIAN_H	|| \
@@ -317,6 +318,12 @@ runtest tree_h		TREE_H		|| true
 runtest vasprintf	VASPRINTF	-D_GNU_SOURCE || true
 runtest vis		VIS		-DLIBBSD_OPENBSD_VIS	|| true
 
+if [ ${HAVE_VIS} -eq 1 ]; then
+	if singletest broken-strnvis BROKEN_STRNVIS "-Wall -Werror"; then
+		HAVE_BROKEN_STRNVIS=1
+	fi
+fi
+
 if [ ${HAVE_ARC4RANDOM} -eq 1 -a ${HAVE_ARC4RANDOM_BUF} -eq 0 ]; then
 	COMPATS="compat/arc4random.c ${COMPATS}"
 fi
@@ -648,6 +655,8 @@ cat <<__HEREDOC__
 #  define HOST_NAME_MAX 255
 # endif
 #endif
+
+#define HAVE_BROKEN_STRNVIS ${HAVE_BROKEN_STRNVIS}
 __HEREDOC__
 
 echo "file config.h: written" 1>&2

ge.c

@@ -83,7 +83,7 @@ log_request(struct client *c, int code, const char *meta)
 			strlcpy(cntmp, subj + 4, sizeof(cntmp));
 			if ((n = strchr(cntmp, '/')) != NULL)
 				*n = '\0';
-			strnvis(cn, cntmp, sizeof(cn), VIS_WHITE|VIS_DQ);
+			gmid_strnvis(cn, cntmp, sizeof(cn), VIS_WHITE|VIS_DQ);
 		}
 	}
 

gmid.c

@@ -140,7 +140,7 @@ log_request(struct client *c, int code, const char *meta)
 			strlcpy(cntmp, subj + 4, sizeof(cntmp));
 			if ((n = strchr(cntmp, '/')) != NULL)
 				*n = '\0';
-			strnvis(cn, cntmp, sizeof(cn), VIS_WHITE|VIS_DQ);
+			gmid_strnvis(cn, cntmp, sizeof(cn), VIS_WHITE|VIS_DQ);
 		}
 	}
 

gmid.h

@@ -469,5 +469,6 @@ EVP_PKEY	*ssl_load_pkey(const uint8_t *, size_t);
 struct vhost	*new_vhost(void);
 struct location	*new_location(void);
 struct proxy	*new_proxy(void);
+int		 gmid_strnvis(char *, const char *, size_t, int);
 
 #endif

have/broken-strnvis.c

@@ -0,0 +1,15 @@
+/*
+ * public domain
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <vis.h>
+
+int
+main(void)
+{
+	char buf[128];
+
+	return strnvis(buf, sizeof(buf), "Hello, world!\n", 0);
+}

utils.c

@@ -22,6 +22,7 @@
 
 #include <errno.h>
 #include <string.h>
+#include <vis.h>	/* for gmid_strnvis() */
 
 #include <openssl/ec.h>
 #include <openssl/err.h>
@@ -496,3 +497,19 @@ new_proxy(void)
 	p->protocols = TLS_PROTOCOLS_DEFAULT;
 	return p;
 }
+
+/*
+ * I can't rant enough about this situation.  As far as I've understood,
+ * OpenBSD introduced strnvis(3) with a signature, then NetBSD did it but
+ * with a incompatible signature.  FreeBSD followed NetBSD.  libbsd followed
+ * OpenBSD but now is thinking to switch.  WTF?
+ */
+int
+gmid_strnvis(char *dst, const char *src, size_t destsize, int flag)
+{
+#if HAVE_BROKEN_STRNVIS
+	return strnvis(dst, destsize, src, flag);
+#else
+	return strnvis(dst, src, destsize, flag);
+#endif
+}