1 //
2 //
3 // Copyright 2015 gRPC authors.
4 //
5 // Licensed under the Apache License, Version 2.0 (the "License");
6 // you may not use this file except in compliance with the License.
7 // You may obtain a copy of the License at
8 //
9 // http://www.apache.org/licenses/LICENSE-2.0
10 //
11 // Unless required by applicable law or agreed to in writing, software
12 // distributed under the License is distributed on an "AS IS" BASIS,
13 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 // See the License for the specific language governing permissions and
15 // limitations under the License.
16 //
17 //
18
19 // for secure_getenv.
20 #ifndef _GNU_SOURCE
21 #define _GNU_SOURCE
22 #endif
23
24 #include <grpc/support/port_platform.h>
25
26 #include <string>
27
28 #include "absl/types/optional.h"
29
30 #ifdef GPR_LINUX_ENV
31
32 #if defined(GPR_BACKWARDS_COMPATIBILITY_MODE)
33 #include <dlfcn.h>
34 #endif
35
36 #include <features.h>
37 #include <stdlib.h>
38
39 #include "src/core/lib/gprpp/env.h"
40
41 namespace grpc_core {
42
GetEnv(const char * name)43 absl::optional<std::string> GetEnv(const char* name) {
44 char* result = nullptr;
45 #if defined(GPR_BACKWARDS_COMPATIBILITY_MODE)
46 typedef char* (*getenv_type)(const char*);
47 static getenv_type getenv_func = nullptr;
48 // Check to see which getenv variant is supported (go from most
49 // to least secure)
50 if (getenv_func == nullptr) {
51 for (auto name : {"secure_getenv", "__secure_getenv", "getenv"}) {
52 getenv_func = reinterpret_cast<getenv_type>(dlsym(RTLD_DEFAULT, name));
53 if (getenv_func != nullptr) {
54 break;
55 }
56 }
57 }
58 result = getenv_func(name);
59 #elif __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 17)
60 result = secure_getenv(name);
61 #else
62 result = getenv(name);
63 #endif
64 if (result == nullptr) return absl::nullopt;
65 return result;
66 }
67
SetEnv(const char * name,const char * value)68 void SetEnv(const char* name, const char* value) {
69 int res = setenv(name, value, 1);
70 if (res != 0) abort();
71 }
72
UnsetEnv(const char * name)73 void UnsetEnv(const char* name) {
74 int res = unsetenv(name);
75 if (res != 0) abort();
76 }
77
78 } // namespace grpc_core
79
80 #endif // GPR_LINUX_ENV
81