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authorJohn Högberg <[email protected]>2017-11-22 13:19:57 +0100
committerJohn Högberg <[email protected]>2018-01-03 08:14:28 +0100
commitc2d70945dce9cb09d5d7120d6e9ddf7faac8d230 (patch)
tree3cfbaca9af7b6a32871e669a39027ce987c846da /erts/emulator/test/driver_SUITE.erl
parentbe9f93b14e0fb9ff09db36abde62ae8099bf5bd0 (diff)
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Replace the libc environment with a thread-safe emulation
putenv(3) and friends aren't thread-safe regardless of how you slice it; a global lock around all environment operations (like before) keeps things safe as far as our own operations go, but we have absolutely no control over what libc or a library dragged in by a driver/NIF does -- they're free to call getenv(3) or putenv(3) without honoring our lock. This commit solves this by setting up an "emulated" environment which can't be touched without going through our interfaces. Third-party libraries can still shoot themselves in the foot but benign uses of os:putenv/2 will no longer risk crashing the emulator.
Diffstat (limited to 'erts/emulator/test/driver_SUITE.erl')
-rw-r--r--erts/emulator/test/driver_SUITE.erl47
1 files changed, 47 insertions, 0 deletions
diff --git a/erts/emulator/test/driver_SUITE.erl b/erts/emulator/test/driver_SUITE.erl
index 475e03087a..884f697384 100644
--- a/erts/emulator/test/driver_SUITE.erl
+++ b/erts/emulator/test/driver_SUITE.erl
@@ -80,6 +80,7 @@
async_blast/1,
thr_msg_blast/1,
consume_timeslice/1,
+ env/1,
z_test/1]).
-export([bin_prefix/2]).
@@ -166,6 +167,7 @@ all() -> %% Keep a_test first and z_test last...
async_blast,
thr_msg_blast,
consume_timeslice,
+ env,
z_test].
groups() ->
@@ -2360,6 +2362,51 @@ count_proc_sched(Ps, PNs) ->
PNs
end.
+%%
+%% Tests whether erl_drv_putenv reflects in os:getenv and vice versa.
+%%
+env(Config) when is_list(Config) ->
+ ok = load_driver(proplists:get_value(data_dir, Config), env_drv),
+ Port = open_port({spawn_driver, env_drv}, []),
+ true = is_port(Port),
+
+ Keys = ["env_drv_a_key", "env_drv_b_key", "env_drv_c_key"],
+ Values = ["a_value", "b_value", "c_value"],
+
+ [env_put_test(Port, Key, Value) || Key <- Keys, Value <- Values],
+ [env_get_test(Port, Key, Value) || Key <- Keys, Value <- Values],
+ [env_oversize_test(Port, Key) || Key <- Keys],
+ [env_notfound_test(Port, Key) || Key <- Keys],
+
+ true = port_close(Port),
+ erl_ddll:unload_driver(env_drv),
+ ok.
+
+env_control(Port, Command, Key, Value) ->
+ KeyBin = list_to_binary(Key),
+ ValueBin = list_to_binary(Value),
+ Header = <<(byte_size(KeyBin)), (byte_size(ValueBin))>>,
+ Payload = <<KeyBin/binary, ValueBin/binary>>,
+ port_control(Port, Command, <<Header/binary, Payload/binary>>).
+
+env_put_test(Port, Key, Value) ->
+ os:unsetenv(Key),
+ [0] = env_control(Port, 0, Key, Value),
+ Value = os:getenv(Key).
+
+env_get_test(Port, Key, ExpectedValue) ->
+ true = os:putenv(Key, ExpectedValue),
+ [0] = env_control(Port, 1, Key, ExpectedValue).
+
+env_oversize_test(Port, Key) ->
+ os:putenv(Key, [$A || _ <- lists:seq(1, 1024)]),
+ [127] = env_control(Port, 1, Key, "").
+
+env_notfound_test(Port, Key) ->
+ true = os:unsetenv(Key),
+ [255] = env_control(Port, 1, Key, "").
+
+
a_test(Config) when is_list(Config) ->
rpc(Config, fun check_io_debug/0).