Fix: GCC unaligned pointer warnings

The release of GCC 9 added the following warning:

	-Waddress-of-packed-member, enabled by default, warns about an
	unaligned pointer value from the address of a packed member of a
	struct or union.

The warning is triggered in some place in LTTng-UST in cases where we
pass a pointer to get a result. Rather than passing the pointer directly
from the struct member, we get the result into a local storage, then
write into in the struct.

Signed-off-by: Gabriel-Andrew Pollo-Guilbert <gabriel.pollo-guilbert@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/liblttng-ust-comm/lttng-ust-comm.c b/liblttng-ust-comm/lttng-ust-comm.c
index 3d1c65038295062559db6dd415fe2b03304d5ec2..36095a1c48027f09e7ef5fddb869a08ebe005418 100644 (file)
--- a/liblttng-ust-comm/lttng-ust-comm.c
+++ b/liblttng-ust-comm/lttng-ust-comm.c
@@ -853,12 +853,15 @@ static
 int serialize_integer_type(struct ustctl_integer_type *uit,
                const struct lttng_integer_type *lit)
 {
+       int32_t encoding;
+
        uit->size = lit->size;
        uit->signedness = lit->signedness;
        uit->reverse_byte_order = lit->reverse_byte_order;
        uit->base = lit->base;
-       if (serialize_string_encoding(&uit->encoding, lit->encoding))
+       if (serialize_string_encoding(&encoding, lit->encoding))
                return -EINVAL;
+       uit->encoding = encoding;
        uit->alignment = lit->alignment;
        return 0;
 }
@@ -880,9 +883,11 @@ int serialize_basic_type(struct lttng_session *session,
        }
        case atype_string:
        {
-               if (serialize_string_encoding(&ubt->string.encoding,
-                               lbt->string.encoding))
+               int32_t encoding;
+
+               if (serialize_string_encoding(&encoding, lbt->string.encoding))
                        return -EINVAL;
+               ubt->string.encoding = encoding;
                *uatype = ustctl_atype_string;
                break;
        }
@@ -1008,13 +1013,15 @@ int serialize_one_field(struct lttng_session *session,
        {
                struct ustctl_field *uf = &fields[*iter_output];
                struct ustctl_type *ut = &uf->type;
+               enum ustctl_abstract_types atype;
 
                strncpy(uf->name, lf->name, LTTNG_UST_SYM_NAME_LEN);
                uf->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
-               ret = serialize_basic_type(session, &ut->atype, lt->atype,
+               ret = serialize_basic_type(session, &atype, lt->atype,
                        &ut->u.basic, &lt->u.basic);
                if (ret)
                        return ret;
+               ut->atype = atype;
                (*iter_output)++;
                break;
        }
@@ -1024,6 +1031,7 @@ int serialize_one_field(struct lttng_session *session,
                struct ustctl_type *ut = &uf->type;
                struct ustctl_basic_type *ubt;
                const struct lttng_basic_type *lbt;
+               enum ustctl_abstract_types atype;
 
                strncpy(uf->name, lf->name, LTTNG_UST_SYM_NAME_LEN);
                uf->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
@@ -1031,10 +1039,11 @@ int serialize_one_field(struct lttng_session *session,
                ubt = &ut->u.array.elem_type;
                lbt = &lt->u.array.elem_type;
                ut->u.array.length = lt->u.array.length;
-               ret = serialize_basic_type(session, &ubt->atype, lbt->atype,
+               ret = serialize_basic_type(session, &atype, lbt->atype,
                        &ubt->u.basic, &lbt->u.basic);
                if (ret)
                        return -EINVAL;
+               ubt->atype = atype;
                ut->atype = ustctl_atype_array;
                (*iter_output)++;
                break;
@@ -1045,6 +1054,7 @@ int serialize_one_field(struct lttng_session *session,
                struct ustctl_type *ut = &uf->type;
                struct ustctl_basic_type *ubt;
                const struct lttng_basic_type *lbt;
+               enum ustctl_abstract_types atype;
                int ret;
 
                strncpy(uf->name, lf->name, LTTNG_UST_SYM_NAME_LEN);
@@ -1052,16 +1062,18 @@ int serialize_one_field(struct lttng_session *session,
                uf->type.atype = ustctl_atype_sequence;
                ubt = &ut->u.sequence.length_type;
                lbt = &lt->u.sequence.length_type;
-               ret = serialize_basic_type(session, &ubt->atype, lbt->atype,
+               ret = serialize_basic_type(session, &atype, lbt->atype,
                        &ubt->u.basic, &lbt->u.basic);
                if (ret)
                        return -EINVAL;
+               ubt->atype = atype;
                ubt = &ut->u.sequence.elem_type;
                lbt = &lt->u.sequence.elem_type;
-               ret = serialize_basic_type(session, &ubt->atype, lbt->atype,
+               ret = serialize_basic_type(session, &atype, lbt->atype,
                        &ubt->u.basic, &lbt->u.basic);
                if (ret)
                        return -EINVAL;
+               ubt->atype = atype;
                ut->atype = ustctl_atype_sequence;
                (*iter_output)++;
                break;

diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c
index faea043d13124df27a152b438da4f6f16ef984a2..889445783bac3c160585a8e63d73ee88fe2f2a3e 100644 (file)
--- a/liblttng-ust/lttng-ust-comm.c
+++ b/liblttng-ust/lttng-ust-comm.c
@@ -871,14 +871,18 @@ int handle_message(struct sock_info *sock_info,
        }
        case LTTNG_UST_STREAM:
        {
+               uint64_t memory_map_size;
+
                /* Receive shm_fd, wakeup_fd */
                ret = ustcomm_recv_stream_from_sessiond(sock,
-                       &lum->u.stream.len,
+                       &memory_map_size,
                        &args.stream.shm_fd,
                        &args.stream.wakeup_fd);
                if (ret) {
                        goto error;
                }
+               lum->u.stream.len = memory_map_size;
+
                if (ops->cmd)
                        ret = ops->cmd(lum->handle, lum->cmd,
                                        (unsigned long) &lum->u,