Fix strict aliasing problems or add -fno-strict-aliasing

Create a new CFLAGS_NOSTRICT Autoconf substitution variable which
is set to -fno-strict-aliasing if we're using gcc to compile.  Add
@CFLAGS_NOSTRICT@ to the C compiler flags for source files that have
significant strict-aliasing issues.

Fix minor strict-aliasing issues elsewhere in the tree by using memcpy
to copy the data into a properly typed variable.

Change-Id: I43afdb5e33e06cb249b7db385a65daf8d2133a19
Reviewed-on: http://gerrit.openafs.org/1617
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>

diff --git a/src/budb/ol_verify.c b/src/budb/ol_verify.c
index 5a57e9e5ab36e33c6123748cf1b7c18d7f93cf12..0ca22a5976da7f9125dc04518fb73b23e4e8fbf9 100644 (file)
--- a/src/budb/ol_verify.c
+++ b/src/budb/ol_verify.c
@@ -935,6 +935,7 @@ verifyEntryChains(struct ubik_trans *ut)
 {
     afs_int32 code;
     afs_int32 offset;
+    afs_int32 start;
     int blockIndex, entryIndex;
     char entry[sizeof(struct block)];
     int entrySize;
@@ -966,7 +967,8 @@ verifyEntryChains(struct ubik_trans *ut)
                return BUDB_IO;
 
            /* check if entry is free by looking at the first "afs_int32" of the structure */
-           if (*((afs_int32 *) & entry[0]) == 0) {     /* zero is free */
+           memcpy(&start, entry, sizeof(start));
+           if (start == 0) {   /* zero is free */
                /* Is it on any hash chain? */
                if (blockMap[blockIndex]->entries[entryIndex] & MAP_HASHES) {
                    Log("Entry: blockindex %d, entryindex %d - marked free but hashed 0x%x\n", blockIndex, entryIndex, blockMap[blockIndex]->entries[entryIndex]);

diff --git a/src/budb/procs.c b/src/budb/procs.c
index 34eb55cd0ca5fea32717d2bbc72864a72ce2cc0f..1ef235faee147e709affd48a3f476b46392d6665 100644 (file)
--- a/src/budb/procs.c
+++ b/src/budb/procs.c
@@ -3405,6 +3405,9 @@ T_DumpHashTable(struct rx_call *call, int type, char *filename)
     afs_uint32 hash;
     dbadr a, first_a;
     char e[sizeof(struct block)];      /* unnecessarily conservative */
+    struct dump e_dump;
+    struct tape e_tape;
+    struct volInfo e_volinfo;
     int e_size;
     int old;
 
@@ -3448,16 +3451,20 @@ T_DumpHashTable(struct rx_call *call, int type, char *filename)
                    fprintf(DUMP, "    at %d is ", a);
                switch (type) {
                case HT_dumpIden_FUNCTION:
-                   fprintf(DUMP, "%d\n", ntohl(((struct dump *)e)->id));
+                   memcpy(&e_dump, e, sizeof(e_dump));
+                   fprintf(DUMP, "%d\n", ntohl(e_dump.id));
                    break;
                case HT_dumpName_FUNCTION:
-                   fprintf(DUMP, "%s\n", ((struct dump *)e)->dumpName);
+                   memcpy(&e_dump, e, sizeof(e_dump));
+                   fprintf(DUMP, "%s\n", e_dump.dumpName);
                    break;
                case HT_tapeName_FUNCTION:
-                   fprintf(DUMP, "%s\n", ((struct tape *)e)->name);
+                   memcpy(&e_tape, e, sizeof(e_tape));
+                   fprintf(DUMP, "%s\n", e_tape.name);
                    break;
                case HT_volName_FUNCTION:
-                   fprintf(DUMP, "%s\n", ((struct volInfo *)e)->name);
+                   memcpy(&e_volinfo, e, sizeof(e_volinfo));
+                   fprintf(DUMP, "%s\n", e_volinfo.name);
                    break;
                }
                if ((ht_HashEntry(mht, e) % length) != hash)

diff --git a/src/cf/osconf.m4 b/src/cf/osconf.m4
index 2622cf7470d65fe334b41e6ca9b4da8d589728d9..7d6be576bcef9b60df7071d6f9fc7d2b55b0c405 100644 (file)
--- a/src/cf/osconf.m4
+++ b/src/cf/osconf.m4
@@ -1135,6 +1135,12 @@ if test "x$GCC" = "xyes"; then
   fi
 fi
 
+CFLAGS_NOSTRICT=
+
+if test "x$GCC" = "xyes"; then
+  CFLAGS_NOSTRICT="-fno-strict-aliasing"
+fi
+
 if test "x$GCC" = "xyes"; then
   CFLAGS_NOUNUSED="-Wno-unused"
 else
@@ -1191,6 +1197,7 @@ AC_SUBST(TXLIBS)
 AC_SUBST(VFSCK_CFLAGS)
 AC_SUBST(XCFLAGS)
 AC_SUBST(CFLAGS_NOERROR)
+AC_SUBST(CFLAGS_NOSTRICT)
 AC_SUBST(CFLAGS_NOUNUSED)
 AC_SUBST(XCFLAGS64)
 AC_SUBST(XLDFLAGS)

diff --git a/src/kauth/krb_udp.c b/src/kauth/krb_udp.c
index 7d516cf836d26a54b65fde343a4c219ed25290c9..9f4f364e26c2fab3ccc8467c4db46bf7c17d7ede 100644 (file)
--- a/src/kauth/krb_udp.c
+++ b/src/kauth/krb_udp.c
@@ -307,7 +307,8 @@ UDP_Authenticate(int ksoc, struct sockaddr_in *client, char *name,
            afs_uint32 temp;    /* unsigned for safety */
            afs_uint32 pwexpires;
 
-           temp = ntohl(*((afs_int32 *) (tentry.misc_auth_bytes)));
+           memcpy(&temp, tentry.misc_auth_bytes, sizeof(afs_uint32));
+           temp = ntohl(temp);
            unpack_long(temp, misc_auth_bytes);
            pwexpires = misc_auth_bytes[0];
            if (pwexpires) {

diff --git a/src/ptserver/Makefile.in b/src/ptserver/Makefile.in
index a55177a6ea5affe17b9c6fd4907835f902e09c6a..aab2feef3daad324e14ffaf096d0730da6f6dbff 100644 (file)
--- a/src/ptserver/Makefile.in
+++ b/src/ptserver/Makefile.in
@@ -95,9 +95,13 @@ ptserver: ptserver.o ptutils.o ptprocs.o ptint.ss.o ptint.xdr.o utils.o $(LIBS)
 
 ptserver.o: ptserver.c ${INCLS} AFS_component_version_number.c
 
+# When supergroups is enabled, some parts of ptserver cast between
+# incompatible structs.
 ptutils.o: ptutils.c ${INCLS}
+       $(CCOBJ) $(CFLAGS) @CFLAGS_NOSTRICT@ -c ptutils.c
 
 ptprocs.o: ptprocs.c ${INCLS}
+       $(CCOBJ) $(CFLAGS) @CFLAGS_NOSTRICT@ -c ptprocs.c
 
 utils.o: utils.c ${INCLS} 
 

diff --git a/src/ptserver/ptclient.c b/src/ptserver/ptclient.c
index cacf8c76a8e1d93a454e4113f3dcf357ba6816df..a62b579f5cce7da169931664703c3df5bfb2fb72 100644 (file)
--- a/src/ptserver/ptclient.c
+++ b/src/ptserver/ptclient.c
@@ -133,7 +133,9 @@ PrintEntry(afs_int32 ea, struct prentry *e, int indent)
 {
     /* handle screwed up versions of DumpEntry */
     if (e->flags & PRCONT) {
-       afs_int32 id = *(afs_int32 *) (e->name);
+       afs_int32 id;
+
+       memcpy(&id, e->name, sizeof(id));
        if ((id != PRBADID) && ((id > (1 << 24)) || (id < -(1 << 24)))) {
            /* assume server incorrectly swapped these bytes... */
            int i = 0;

diff --git a/src/tsalvaged/Makefile.in b/src/tsalvaged/Makefile.in
index 464b6ce084adf568e22cf73fdc86944fdc345c28..c1ea3328226b8df249d23485adeaba506ac246af 100644 (file)
--- a/src/tsalvaged/Makefile.in
+++ b/src/tsalvaged/Makefile.in
@@ -62,8 +62,9 @@ vol-salvage.o: ${VOL}/vol-salvage.c
 physio.o: ${VOL}/physio.c
        ${CCRULE}
 
+# Uses an alignment hack to convert between incompatible pointers.
 fssync-debug.o: ${VOL}/fssync-debug.c
-       ${CCRULE}
+       $(CCOBJ) $(CFLAGS) @CFLAGS_NOSTRICT@ -c ${VOL}/fssync-debug.c
 
 salvsync-debug.o: salvsync-debug.c
        ${CCRULE}

diff --git a/src/vol/Makefile.in b/src/vol/Makefile.in
index 1afeabd564f529c351dea5d4f332a1381f6a82d1..a46f528cf005ff8736da2088f72dbab84bb5a42c 100644 (file)
--- a/src/vol/Makefile.in
+++ b/src/vol/Makefile.in
@@ -225,6 +225,10 @@ volinfo: vol-info.o physio.o ihandle.o ${LIBS}
        ${CC} ${CFLAGS} -o volinfo vol-info.o physio.o \
                ihandle.o ${LIBS} ${XLIBS}
 
+# Uses an alignment hack to convert between incompatible pointers.
+fssync-debug.o: fssync-debug.c
+       $(CCOBJ) $(CFLAGS) @CFLAGS_NOSTRICT@ -c fssync-debug.c
+
 fssync-debug: fssync-debug.o physio.o AFS_component_version_number.c ${LIBS}
        ${CC} ${LDFLAGS} -o fssync-debug fssync-debug.o physio.o ${LIBS} ${XLIBS}