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authorJohn Högberg <[email protected]>2018-04-24 13:30:00 +0200
committerJohn Högberg <[email protected]>2018-04-24 14:20:06 +0200
commit05b1c13e36ec49891e89593b25e668e983a4fc41 (patch)
treec5c8474cfbf9516fe1818bbfb66757057bdfcb9b
parent74a95b3d511177a9b35c2b0272b9ca5511b6f750 (diff)
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heart: Use ntohs instead of manual conversion
Multiplying a signed char by 256 is undefined behavior and caused problems on some platforms when the length was long enough. We could cast it to an unsigned int to make it work, but it's best not to reinvent the wheel. Fixes OTP-15034
-rw-r--r--erts/etc/common/heart.c5
-rw-r--r--lib/kernel/test/heart_SUITE.erl13
2 files changed, 11 insertions, 7 deletions
diff --git a/erts/etc/common/heart.c b/erts/etc/common/heart.c
index 01ef840b5d..aaaffbca79 100644
--- a/erts/etc/common/heart.c
+++ b/erts/etc/common/heart.c
@@ -847,11 +847,8 @@ write_message(fd, mp)
int fd;
struct msg *mp;
{
- int len;
- char* tmp;
+ int len = ntohs(mp->len);
- tmp = (char*) &(mp->len);
- len = (*tmp * 256) + *(tmp+1);
if ((len == 0) || (len > MSG_BODY_SIZE)) {
return MSG_HDR_SIZE;
} /* cc68k wants (char *) */
diff --git a/lib/kernel/test/heart_SUITE.erl b/lib/kernel/test/heart_SUITE.erl
index 83efbb4c35..02954aa54c 100644
--- a/lib/kernel/test/heart_SUITE.erl
+++ b/lib/kernel/test/heart_SUITE.erl
@@ -352,9 +352,16 @@ clear_cmd(Config) when is_list(Config) ->
get_cmd(suite) -> [];
get_cmd(Config) when is_list(Config) ->
{ok, Node} = start_check(slave, heart_test),
- Cmd = "test",
- ok = rpc:call(Node, heart, set_cmd, [Cmd]),
- {ok, Cmd} = rpc:call(Node, heart, get_cmd, []),
+
+ ShortCmd = "test",
+ ok = rpc:call(Node, heart, set_cmd, [ShortCmd]),
+ {ok, ShortCmd} = rpc:call(Node, heart, get_cmd, []),
+
+ %% This would hang prior to OTP-15024 being fixed.
+ LongCmd = [$a || _ <- lists:seq(1, 160)],
+ ok = rpc:call(Node, heart, set_cmd, [LongCmd]),
+ {ok, LongCmd} = rpc:call(Node, heart, get_cmd, []),
+
stop_node(Node),
ok.