*: eliminate more aliasing warnings

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

6 files changed, 40 insertions, 36 deletions

diff --git a/include/platform.h b/include/platform.h
index ab4402e79..dcc61a77b 100644
--- a/include/platform.h
+++ b/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))
-# define move_from_unaligned16(v, u16p) ((v) = *(uint16_t*)(u16p))
-# define move_from_unaligned32(v, u32p) ((v) = *(uint32_t*)(u32p))
-# define move_to_unaligned32(u32p, v)   (*(uint32_t*)(u32p) = (v))
+# include <stdint.h>
+typedef int      bb__aliased_int      FIX_ALIASING;
+typedef uint16_t bb__aliased_uint16_t FIX_ALIASING;
+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) */
diff --git a/libbb/udp_io.c b/libbb/udp_io.c
index d9375eac2..24237be99 100644
--- a/libbb/udp_io.c
+++ b/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
diff --git a/networking/ipcalc.c b/networking/ipcalc.c
index 18abc12eb..78558495e 100644
--- a/networking/ipcalc.c
+++ b/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;
-        in_addr_t netmask, broadcast, network, ipaddr;
-        struct in_addr a;
+        bool have_netmask = 0;
+        struct in_addr s_netmask, s_broadcast, s_network, s_ipaddr;
+        /* 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++;
+                                *prefixstr++ = '\0';
                                 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");
                 }
-
-                netmask = inet_aton(argv[1], &a);
-                if (netmask == 0) {
+                if (inet_aton(argv[1], &s_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) {
diff --git a/networking/udhcp/arpping.c b/networking/udhcp/arpping.c
index 548796e2b..cf18153f7 100644
--- a/networking/udhcp/arpping.c
+++ b/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
diff --git a/util-linux/mkswap.c b/util-linux/mkswap.c
index 949c71a78..7e32d91ed 100644
--- a/util-linux/mkswap.c
+++ b/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)
diff --git a/util-linux/volume_id/linux_raid.c b/util-linux/volume_id/linux_raid.c
index d1bf0c308..e1c86369d 100644
--- a/util-linux/volume_id/linux_raid.c
+++ b/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);