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author | John Högberg <[email protected]> | 2017-11-22 13:19:57 +0100 |
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committer | John Högberg <[email protected]> | 2018-01-03 08:14:28 +0100 |
commit | c2d70945dce9cb09d5d7120d6e9ddf7faac8d230 (patch) | |
tree | 3cfbaca9af7b6a32871e669a39027ce987c846da /erts/emulator/test/driver_SUITE_data/env_drv.c | |
parent | be9f93b14e0fb9ff09db36abde62ae8099bf5bd0 (diff) | |
download | otp-c2d70945dce9cb09d5d7120d6e9ddf7faac8d230.tar.gz otp-c2d70945dce9cb09d5d7120d6e9ddf7faac8d230.tar.bz2 otp-c2d70945dce9cb09d5d7120d6e9ddf7faac8d230.zip |
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_data/env_drv.c')
-rw-r--r-- | erts/emulator/test/driver_SUITE_data/env_drv.c | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/erts/emulator/test/driver_SUITE_data/env_drv.c b/erts/emulator/test/driver_SUITE_data/env_drv.c new file mode 100644 index 0000000000..0e910eeb84 --- /dev/null +++ b/erts/emulator/test/driver_SUITE_data/env_drv.c @@ -0,0 +1,108 @@ +/* + * %CopyrightBegin% + * + * Copyright Ericsson AB 2017. All Rights Reserved. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + * + * %CopyrightEnd% + */ + +/* Tests whether erl_drv_putenv/erl_drv_getenv work correctly and reflect + * changes to os:putenv/getenv. */ + +#include <string.h> +#include <stdio.h> + +#include "erl_driver.h" + +static ErlDrvSSizeT env_drv_ctl(ErlDrvData drv_data, unsigned int cmd, + char* buf, ErlDrvSizeT len, char** rbuf, ErlDrvSizeT rsize); + +static ErlDrvEntry env_drv_entry = { + NULL /* init */, + NULL /* start */, + NULL /* stop */, + NULL /* output */, + NULL /* ready_input */, + NULL /* ready_output */, + "env_drv", + NULL /* finish */, + NULL /* handle */, + env_drv_ctl, + NULL /* timeout */, + NULL /* outputv*/, + NULL /* ready_async */, + NULL /* flush */, + NULL /* call*/, + NULL /* event */, + ERL_DRV_EXTENDED_MARKER, + ERL_DRV_EXTENDED_MAJOR_VERSION, + ERL_DRV_EXTENDED_MINOR_VERSION, + ERL_DRV_FLAG_USE_PORT_LOCKING, + NULL /* handle2 */, + NULL /* handle_monitor */ +}; + +DRIVER_INIT(env_drv) { + return &env_drv_entry; +} + +static int test_putenv(ErlDrvData drv_data, char *buf, ErlDrvSizeT len) { + char key[256], value[256]; + int key_len, value_len; + + key_len = buf[0]; + value_len = buf[1]; + + sprintf(key, "%.*s", key_len, &buf[2]); + sprintf(value, "%.*s", value_len, &buf[2 + key_len]); + + return erl_drv_putenv(key, value); +} + +static int test_getenv(ErlDrvData drv_data, char *buf, ErlDrvSizeT len) { + char expected_value[256], stored_value[256], key[256]; + int expected_value_len, key_len; + size_t stored_value_len; + int res; + + key_len = buf[0]; + sprintf(key, "%.*s", key_len, &buf[2]); + + expected_value_len = buf[1]; + sprintf(expected_value, "%.*s", expected_value_len, &buf[2 + key_len]); + + stored_value_len = sizeof(stored_value); + res = erl_drv_getenv(key, stored_value, &stored_value_len); + + if(res == 0) { + return strcmp(stored_value, expected_value) != 0; + } else if(res == 1) { + return 127; + } + + return 255; +} + +static ErlDrvSSizeT env_drv_ctl(ErlDrvData drv_data, unsigned int cmd, + char* buf, ErlDrvSizeT len, char** rbuf, ErlDrvSizeT rsize) { + + if(cmd == 0) { + (**rbuf) = (char)test_putenv(drv_data, buf, len); + } else { + (**rbuf) = (char)test_getenv(drv_data, buf, len); + } + + return 1; +} |