*: eliminate more aliasing warnings

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

include/platform.h

@@ -201,10 +201,14 @@
  * a lvalue. This makes it more likely to not swap them by mistake
  */
 #if defined(i386) || defined(__x86_64__)
-# define move_from_unaligned_int(v, intp) ((v) = *(int*)(intp))
+# include <stdint.h>
-# define move_from_unaligned16(v, u16p) ((v) = *(uint16_t*)(u16p))
+typedef int      bb__aliased_int      FIX_ALIASING;
-# define move_from_unaligned32(v, u32p) ((v) = *(uint32_t*)(u32p))
+typedef uint16_t bb__aliased_uint16_t FIX_ALIASING;
-# define move_to_unaligned32(u32p, v)   (*(uint32_t*)(u32p) = (v))
+typedef uint32_t bb__aliased_uint32_t FIX_ALIASING;
+# define move_from_unaligned_int(v, intp) ((v) = *(bb__aliased_int*)(intp))
+# define move_from_unaligned16(v, u16p) ((v) = *(bb__aliased_uint16_t*)(u16p))
+# define move_from_unaligned32(v, u32p) ((v) = *(bb__aliased_uint32_t*)(u32p))
+# define move_to_unaligned32(u32p, v)   (*(bb__aliased_uint32_t*)(u32p) = (v))
 /* #elif ... - add your favorite arch today! */
 #else
 /* performs reasonably well (gcc usually inlines memcpy here) */

libbb/udp_io.c

@@ -152,24 +152,24 @@ recv_from_to(int fd, void *buf, size_t len, int flags,
 		if (cmsgptr->cmsg_level == IPPROTO_IP
 		 && cmsgptr->cmsg_type == IP_PKTINFO
 		) {
-# define pktinfo(cmsgptr) ( (struct in_pktinfo*)(CMSG_DATA(cmsgptr)) )
+			const int IPI_ADDR_OFF = offsetof(struct in_pktinfo, ipi_addr);
 			to->sa_family = AF_INET;
+			/*# define pktinfo(cmsgptr) ( (struct in_pktinfo*)(CMSG_DATA(cmsgptr)) )*/
 			/*to4->sin_addr = pktinfo(cmsgptr)->ipi_addr; - may be unaligned */
-			memcpy(&to4->sin_addr, &pktinfo(cmsgptr)->ipi_addr, sizeof(to4->sin_addr));
+			memcpy(&to4->sin_addr, (char*)(CMSG_DATA(cmsgptr)) + IPI_ADDR_OFF, sizeof(to4->sin_addr));
 			/*to4->sin_port = 123; - this data is not supplied by kernel */
-# undef pktinfo
 			break;
 		}
 # if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
 		if (cmsgptr->cmsg_level == IPPROTO_IPV6
 		 && cmsgptr->cmsg_type == IPV6_PKTINFO
 		) {
-#  define pktinfo(cmsgptr) ( (struct in6_pktinfo*)(CMSG_DATA(cmsgptr)) )
+			const int IPI6_ADDR_OFF = offsetof(struct in6_pktinfo, ipi6_addr);
 			to->sa_family = AF_INET6;
+			/*#  define pktinfo(cmsgptr) ( (struct in6_pktinfo*)(CMSG_DATA(cmsgptr)) )*/
 			/*to6->sin6_addr = pktinfo(cmsgptr)->ipi6_addr; - may be unaligned */
-			memcpy(&to6->sin6_addr, &pktinfo(cmsgptr)->ipi6_addr, sizeof(to6->sin6_addr));
+			memcpy(&to6->sin6_addr, (char*)(CMSG_DATA(cmsgptr)) + IPI6_ADDR_OFF, sizeof(to6->sin6_addr));
 			/*to6->sin6_port = 123; */
-#  undef pktinfo
 			break;
 		}
 # endif

networking/ipcalc.c

@@ -75,29 +75,34 @@ int get_prefix(unsigned long netmask);
 #endif
 
 int ipcalc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int ipcalc_main(int argc, char **argv)
+int ipcalc_main(int argc UNUSED_PARAM, char **argv)
 {
 	unsigned opt;
-	int have_netmask = 0;
+	bool have_netmask = 0;
-	in_addr_t netmask, broadcast, network, ipaddr;
+	struct in_addr s_netmask, s_broadcast, s_network, s_ipaddr;
-	struct in_addr a;
+	/* struct in_addr { in_addr_t s_addr; }  and  in_addr_t
+	 * (which in turn is just a typedef to uint32_t)
+	 * are essentially the same type. A few macros for less verbosity: */
+#define netmask   (s_netmask.s_addr)
+#define broadcast (s_broadcast.s_addr)
+#define network   (s_network.s_addr)
+#define ipaddr    (s_ipaddr.s_addr)
 	char *ipstr;
 
 #if ENABLE_FEATURE_IPCALC_LONG_OPTIONS
 	applet_long_options = ipcalc_longopts;
 #endif
 	opt = getopt32(argv, "mbn" IF_FEATURE_IPCALC_FANCY("phs"));
-	argc -= optind;
 	argv += optind;
+	if (opt & SILENT)
+		logmode = LOGMODE_NONE; /* suppress error_msg() output */
 	if (opt & (BROADCAST | NETWORK | NETPREFIX)) {
-		if (argc > 2 || argc <= 0)
+		if (!argv[0] || !argv[1] || argv[2])
 			bb_show_usage();
 	} else {
-		if (argc != 1)
+		if (!argv[0] || argv[1])
 			bb_show_usage();
 	}
-	if (opt & SILENT)
-		logmode = LOGMODE_NONE; /* Suppress error_msg() output */
 
 	ipstr = argv[0];
 	if (ENABLE_FEATURE_IPCALC_FANCY) {
@@ -108,8 +113,7 @@ int ipcalc_main(int argc, char **argv)
 
 		while (*prefixstr) {
 			if (*prefixstr == '/') {
-				*prefixstr = (char)0;
+				*prefixstr++ = '\0';
-				prefixstr++;
 				if (*prefixstr) {
 					unsigned msk;
 					netprefix = xatoul_range(prefixstr, 0, 32);
@@ -130,42 +134,36 @@ int ipcalc_main(int argc, char **argv)
 			prefixstr++;
 		}
 	}
-	ipaddr = inet_aton(ipstr, &a);
 
-	if (ipaddr == 0) {
+	if (inet_aton(ipstr, &s_ipaddr) == 0) {
 		bb_error_msg_and_die("bad IP address: %s", argv[0]);
 	}
-	ipaddr = a.s_addr;
 
-	if (argc == 2) {
+	if (argv[1]) {
 		if (ENABLE_FEATURE_IPCALC_FANCY && have_netmask) {
 			bb_error_msg_and_die("use prefix or netmask, not both");
 		}
-
+		if (inet_aton(argv[1], &s_netmask) == 0) {
-		netmask = inet_aton(argv[1], &a);
-		if (netmask == 0) {
 			bb_error_msg_and_die("bad netmask: %s", argv[1]);
 		}
-		netmask = a.s_addr;
 	} else {
-
 		/* JHC - If the netmask wasn't provided then calculate it */
 		if (!ENABLE_FEATURE_IPCALC_FANCY || !have_netmask)
 			netmask = get_netmask(ipaddr);
 	}
 
 	if (opt & NETMASK) {
-		printf("NETMASK=%s\n", inet_ntoa((*(struct in_addr *) &netmask)));
+		printf("NETMASK=%s\n", inet_ntoa(s_netmask));
 	}
 
 	if (opt & BROADCAST) {
 		broadcast = (ipaddr & netmask) | ~netmask;
-		printf("BROADCAST=%s\n", inet_ntoa((*(struct in_addr *) &broadcast)));
+		printf("BROADCAST=%s\n", inet_ntoa(s_broadcast));
 	}
 
 	if (opt & NETWORK) {
 		network = ipaddr & netmask;
-		printf("NETWORK=%s\n", inet_ntoa((*(struct in_addr *) &network)));
+		printf("NETWORK=%s\n", inet_ntoa(s_network));
 	}
 
 	if (ENABLE_FEATURE_IPCALC_FANCY) {

networking/udhcp/arpping.c

@@ -87,6 +87,7 @@ int FAST_FUNC arpping(uint32_t test_nip,
 	/* wait for arp reply, and check it */
 	timeout_ms = 2000;
 	do {
+		typedef uint32_t aliased_uint32_t FIX_ALIASING;
 		int r;
 		unsigned prevTime = monotonic_ms();
 
@@ -107,7 +108,7 @@ int FAST_FUNC arpping(uint32_t test_nip,
 			 && arp.operation == htons(ARPOP_REPLY)
 			 /* don't check it: Linux doesn't return proper tHaddr (fixed in 2.6.24?) */
 			 /* && memcmp(arp.tHaddr, from_mac, 6) == 0 */
-			 && *((uint32_t *) arp.sInaddr) == test_nip
+			 && *(aliased_uint32_t*)arp.sInaddr == test_nip
 			) {
 				/* if ARP source MAC matches safe_mac
 				 * (which is client's MAC), then it's not a conflict

util-linux/mkswap.c

@@ -65,7 +65,7 @@ struct swap_header_v1 {
 	uint32_t padding[117];   /* 11..127 */
 	uint32_t badpages[1];    /* 128 */
 	/* total 129 32-bit words in 2nd kilobyte */
-};
+} FIX_ALIASING;
 
 #define NWORDS 129
 #define hdr ((struct swap_header_v1*)bb_common_bufsiz1)

util-linux/volume_id/linux_raid.c

@@ -44,6 +44,7 @@ struct mdp_super_block {
 
 int FAST_FUNC volume_id_probe_linux_raid(struct volume_id *id /*,uint64_t off*/, uint64_t size)
 {
+	typedef uint32_t aliased_uint32_t FIX_ALIASING;
 #define off ((uint64_t)0)
 	uint64_t sboff;
 	uint8_t uuid[16];
@@ -63,7 +64,7 @@ int FAST_FUNC volume_id_probe_linux_raid(struct volume_id *id /*,uint64_t off*/,
 	if (mdp->md_magic != cpu_to_le32(MD_MAGIC))
 		return -1;
 
-	*(uint32_t*)uuid = mdp->set_uuid0;
+	*(aliased_uint32_t*)uuid = mdp->set_uuid0;
 	memcpy(&uuid[4], &mdp->set_uuid1, 12);
 	volume_id_set_uuid(id, uuid, UUID_DCE);