1/*
2 * Copyright 2016-present Facebook, Inc.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <folly/portability/Stdlib.h>
18
19#ifdef _WIN32
20
21#include <cstring>
22
23#include <errno.h>
24
25#include <folly/portability/Fcntl.h>
26#include <folly/portability/SysStat.h>
27#include <folly/portability/Windows.h>
28
29extern "C" {
30char* mktemp(char* tn) {
31 return _mktemp(tn);
32}
33
34// While yes, this is for a directory, due to this being windows,
35// a file and directory can't have the same name, resulting in this
36// still working just fine.
37char* mkdtemp(char* tn) {
38 char* ptr = nullptr;
39 auto len = strlen(tn);
40 int ret = 0;
41 do {
42 strcpy(tn + len - 6, "XXXXXX");
43 ptr = mktemp(tn);
44 if (ptr == nullptr || *ptr == '\0') {
45 return nullptr;
46 }
47 ret = mkdir(ptr, 0700);
48 if (ret != 0 && errno != EEXIST) {
49 return nullptr;
50 }
51 } while (ret != 0);
52 return tn;
53}
54
55int mkstemp(char* tn) {
56 char* ptr = nullptr;
57 auto len = strlen(tn);
58 int ret = 0;
59 do {
60 strcpy(tn + len - 6, "XXXXXX");
61 ptr = mktemp(tn);
62 if (ptr == nullptr || *ptr == '\0') {
63 return -1;
64 }
65 ret = open(ptr, O_RDWR | O_EXCL | O_CREAT, S_IRUSR | S_IWUSR);
66 if (ret == -1 && errno != EEXIST) {
67 return -1;
68 }
69 } while (ret == -1);
70 return ret;
71}
72
73char* realpath(const char* path, char* resolved_path) {
74 // I sure hope the caller gave us _MAX_PATH space in the buffer....
75 return _fullpath(resolved_path, path, _MAX_PATH);
76}
77
78int setenv(const char* name, const char* value, int overwrite) {
79 if (overwrite == 0 && getenv(name) != nullptr) {
80 return 0;
81 }
82
83 if (*value != '\0') {
84 auto e = _putenv_s(name, value);
85 if (e != 0) {
86 errno = e;
87 return -1;
88 }
89 return 0;
90 }
91
92 // We are trying to set the value to an empty string, but
93 // _putenv_s deletes entries if the value is an empty string,
94 // and just calling SetEnvironmentVariableA doesn't update
95 // _environ, so we have to do these terrible things.
96 if (_putenv_s(name, " ") != 0) {
97 errno = EINVAL;
98 return -1;
99 }
100
101 // Here lies the documentation we blatently ignore to make
102 // this work >_>...
103 *getenv(name) = '\0';
104 // This would result in a double null termination, which
105 // normally signifies the end of the environment variable
106 // list, so we stick a completely empty environment variable
107 // into the list instead.
108 *(getenv(name) + 1) = '=';
109
110 // If _wenviron is null, the wide environment has not been initialized
111 // yet, and we don't need to try to update it.
112 // We have to do this otherwise we'd be forcing the initialization and
113 // maintenance of the wide environment even though it's never actually
114 // used in most programs.
115 if (_wenviron != nullptr) {
116 wchar_t buf[_MAX_ENV + 1];
117 size_t len;
118 if (mbstowcs_s(&len, buf, _MAX_ENV + 1, name, _MAX_ENV) != 0) {
119 errno = EINVAL;
120 return -1;
121 }
122 *_wgetenv(buf) = u'\0';
123 *(_wgetenv(buf) + 1) = u'=';
124 }
125
126 // And now, we have to update the outer environment to have
127 // a proper empty value.
128 if (!SetEnvironmentVariableA(name, value)) {
129 errno = EINVAL;
130 return -1;
131 }
132 return 0;
133}
134
135int unsetenv(const char* name) {
136 if (_putenv_s(name, "") != 0) {
137 return -1;
138 }
139 return 0;
140}
141}
142
143#endif
144
145#if !__linux__ && !FOLLY_MOBILE
146
147#include <string>
148#include <vector>
149
150extern "C" int clearenv() {
151 std::vector<std::string> data;
152 for (auto it = environ; it && *it; ++it) {
153 std::string entry(*it);
154 auto equalsPosition = entry.find('=');
155 if (equalsPosition == std::string::npos || equalsPosition == 0) {
156 // It's either a drive setting (if on Windows), or something clowny is
157 // going on in the environment.
158 continue;
159 } else {
160 data.emplace_back(entry.substr(0, equalsPosition));
161 }
162 }
163
164 for (auto s : data) {
165 if (unsetenv(s.c_str()) != 0)
166 return -1;
167 }
168
169 return 0;
170}
171
172#endif
173