Address a few compiler warnings on Haiku.

In gencode.c instead of casting pointer types copy the data to squelch 4
previously known warnings from GCC and Clang.  (Oddly enough, Haiku is
the only OS that unconditionally puts a 32-bit array into the union
inside struct in6_addr, yet the only OS where these warnings appeared.)

In pcap.c add a temporary workaround for ioctl() to squelch two other
Clang warnings:

pcap.c:1619:6: error: missing field 'size' initializer
  [-Werror,-Wmissing-field-initializers]
pcap.c:1638:6: error: missing field 'size' initializer
  [-Werror,-Wmissing-field-initializers]

With these changes GCC builds are now warning-free, so in build.sh set
LIBPCAP_TAINTED for Clang only and update the comment to show the
current remaining warnings.

4 files changed, 43 insertions, 21 deletions

diff --git a/CHANGES b/CHANGES
index 30217e7d..86db3d59 100644
--- a/CHANGES
+++ b/CHANGES
@@ -6,6 +6,7 @@ DayOfTheWeek, Month DD, YYYY / The Tcpdump Group
       Remove an always-false pointer test from snf_read().
       Clean up DECnet address handling.
       Finalize moving of bpf_filter.c. (GH #1166)
+      Address a few compiler warnings on Haiku.
     Link-layer types:
       Add LINKTYPE_ETW/DLT_ETW.
       Add LINKTYPE_NETANALYZER_NG/DLT_NETANALYZER_NG (pull request
diff --git a/build.sh b/build.sh
index 956cfe2f..110ce251 100755
--- a/build.sh
+++ b/build.sh
@@ -87,21 +87,16 @@ suncc-5.1[45]/SunOS-5.11)
     # "./filtertest.c", line 281: warning: statement not reached
     LIBPCAP_TAINTED=yes
     ;;
-*/Haiku-*)
-    # (The warnings below come from GCC and Clang in CMake builds after installing
-    # all system updates.)
-    # gencode.c:4143:9: warning: converting a packed 'struct in6_addr' pointer
-    #   (alignment 1) to a 'uint32_t' {aka 'unsigned int'} pointer (alignment 4) may
-    #   result in an unaligned pointer value [-Waddress-of-packed-member]
-    # gencode.c:4144:9: warning: converting a packed 'struct in6_addr' pointer
-    #   (alignment 1) to a 'uint32_t' {aka 'unsigned int'} pointer (alignment 4) may
-    #   result in an unaligned pointer value [-Waddress-of-packed-member]
-    # gencode.c:7189:9: warning: converting a packed 'struct in6_addr' pointer
-    #   (alignment 1) to a 'uint32_t' {aka 'unsigned int'} pointer (alignment 4) may
-    #   result in an unaligned pointer value [-Waddress-of-packed-member]
-    # gencode.c:7190:9: warning: converting a packed 'struct in6_addr' pointer
-    #   (alignment 1) to a 'uint32_t' {aka 'unsigned int'} pointer (alignment 4) may
-    #   result in an unaligned pointer value [-Waddress-of-packed-member]
+clang-*/Haiku-*)
+    # pcap-haiku.c:82:26: error: implicit conversion loses integer precision:
+    #   'ssize_t' (aka 'long') to 'int32_t' (aka 'int')
+    #   [-Werror,-Wshorten-64-to-32]
+    # pcap-haiku.c:88:51: error: implicit conversion loses integer precision:
+    #   'ssize_t' (aka 'long') to 'u_int' (aka 'unsigned int')
+    #   [-Werror,-Wshorten-64-to-32]
+    # pcap-haiku.c:98:15: error: implicit conversion loses integer precision:
+    #   'ssize_t' (aka 'long') to 'bpf_u_int32' (aka 'unsigned int')
+    #   [-Werror,-Wshorten-64-to-32]
     LIBPCAP_TAINTED=yes
     ;;
 esac
diff --git a/gencode.c b/gencode.c
index 7b818ec4..f6a2cac2 100644
--- a/gencode.c
+++ b/gencode.c
@@ -4102,7 +4102,16 @@ gen_hostop6(compiler_state_t *cstate, struct in6_addr *addr,
 {
 	struct block *b0, *b1;
 	u_int offset;
-	uint32_t *a, *m;
+	/*
+	 * Code below needs to access four separate 32-bit parts of the 128-bit
+	 * IPv6 address and mask.  In some OSes this is as simple as using the
+	 * s6_addr32 pseudo-member of struct in6_addr, which contains a union of
+	 * 8-, 16- and 32-bit arrays.  In other OSes this is not the case, as
+	 * far as libpcap sees it.  Hence copy the data before use to avoid
+	 * potential unaligned memory access and the associated compiler
+	 * warnings (whether genuine or not).
+	 */
+	bpf_u_int32 a[4], m[4];
 
 	switch (dir) {
 
@@ -4156,8 +4165,8 @@ gen_hostop6(compiler_state_t *cstate, struct in6_addr *addr,
 		/*NOTREACHED*/
 	}
 	/* this order is important */
-	a = (uint32_t *)addr;
-	m = (uint32_t *)mask;
+	memcpy(a, addr, sizeof(a));
+	memcpy(m, mask, sizeof(m));
 	b1 = gen_mcmp(cstate, OR_LINKPL, offset + 12, BPF_W, ntohl(a[3]), ntohl(m[3]));
 	b0 = gen_mcmp(cstate, OR_LINKPL, offset + 8, BPF_W, ntohl(a[2]), ntohl(m[2]));
 	gen_and(b0, b1);
@@ -7186,7 +7195,7 @@ gen_mcode6(compiler_state_t *cstate, const char *s1, const char *s2,
 	struct in6_addr *addr;
 	struct in6_addr mask;
 	struct block *b;
-	uint32_t *a, *m;
+	bpf_u_int32 a[4], m[4]; /* Same as in gen_hostop6(). */
 
 	/*
 	 * Catch errors reported by us and routines below us, and return NULL
@@ -7215,8 +7224,8 @@ gen_mcode6(compiler_state_t *cstate, const char *s1, const char *s2,
 			(0xff << (8 - masklen % 8)) & 0xff;
 	}
 
-	a = (uint32_t *)addr;
-	m = (uint32_t *)&mask;
+	memcpy(a, addr, sizeof(a));
+	memcpy(m, &mask, sizeof(m));
 	if ((a[0] & ~m[0]) || (a[1] & ~m[1])
 	 || (a[2] & ~m[2]) || (a[3] & ~m[3])) {
 		bpf_error(cstate, "non-network bits set in \"%s/%d\"", s1, masklen);
diff --git a/pcap.c b/pcap.c
index 44ce8a01..6e012da3 100644
--- a/pcap.c
+++ b/pcap.c
@@ -1616,7 +1616,19 @@ pcap_lookupnet(const char *device, bpf_u_int32 *netp, bpf_u_int32 *maskp,
 	ifr.ifr_addr.sa_family = AF_INET;
 #endif
 	(void)pcap_strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
+#if defined(__HAIKU__) && defined(__clang__)
+	/*
+	 * In Haiku R1/beta4 <unistd.h> ioctl() is a macro that needs to take 4
+	 * arguments to initialize its intermediate 2-member structure fully so
+	 * that Clang does not generate a -Wmissing-field-initializers warning
+	 * (which manifests only when it runs with -Werror).  This workaround
+	 * can be removed as soon as there is a Haiku release that fixes the
+	 * problem.  See also https://review.haiku-os.org/c/haiku/+/6369
+	 */
+	if (ioctl(fd, SIOCGIFADDR, (char *)&ifr, sizeof(ifr)) < 0) {
+#else
 	if (ioctl(fd, SIOCGIFADDR, (char *)&ifr) < 0) {
+#endif /* __HAIKU__ && __clang__ */
 		if (errno == EADDRNOTAVAIL) {
 			(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 			    "%s: no IPv4 address assigned", device);
@@ -1635,7 +1647,12 @@ pcap_lookupnet(const char *device, bpf_u_int32 *netp, bpf_u_int32 *maskp,
 	ifr.ifr_addr.sa_family = AF_INET;
 #endif
 	(void)pcap_strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
+#if defined(__HAIKU__) && defined(__clang__)
+	/* Same as above. */
+	if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr, sizeof(ifr)) < 0) {
+#else
 	if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr) < 0) {
+#endif /* __HAIKU__ && __clang__ */
 		pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
 		    errno, "SIOCGIFNETMASK: %s", device);
 		(void)close(fd);