1 // Copyright 2010 Google Inc.
2 // All rights reserved.
3 //
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5 // modification, are permitted provided that the following conditions are
6 // met:
7 //
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9 // notice, this list of conditions and the following disclaimer.
10 // * Redistributions in binary form must reproduce the above copyright
11 // notice, this list of conditions and the following disclaimer in the
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14 // may be used to endorse or promote products derived from this software
15 // without specific prior written permission.
16 //
17 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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22 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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26 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28
29 #include "utils/env.hpp"
30
31 #if defined(HAVE_CONFIG_H)
32 # include "config.h"
33 #endif
34
35 #include <cerrno>
36 #include <cstdlib>
37 #include <cstring>
38 #include <stdexcept>
39
40 #include "utils/format/macros.hpp"
41 #include "utils/logging/macros.hpp"
42 #include "utils/optional.ipp"
43
44 using utils::none;
45 using utils::optional;
46
47
48 extern "C" {
49 extern char** environ;
50 }
51
52
53 /// Gets all environment variables.
54 ///
55 /// \return A mapping of (name, value) pairs describing the environment
56 /// variables.
57 std::map< std::string, std::string >
getallenv(void)58 utils::getallenv(void)
59 {
60 std::map< std::string, std::string > allenv;
61 for (char** envp = environ; *envp != NULL; envp++) {
62 const std::string oneenv = *envp;
63 const std::string::size_type pos = oneenv.find('=');
64 const std::string name = oneenv.substr(0, pos);
65 const std::string value = oneenv.substr(pos + 1);
66
67 PRE(allenv.find(name) == allenv.end());
68 allenv[name] = value;
69 }
70 return allenv;
71 }
72
73
74 /// Gets the value of an environment variable.
75 ///
76 /// \param name The name of the environment variable to query.
77 ///
78 /// \return The value of the environment variable if it is defined, or none
79 /// otherwise.
80 optional< std::string >
getenv(const std::string & name)81 utils::getenv(const std::string& name)
82 {
83 const char* value = std::getenv(name.c_str());
84 if (value == NULL) {
85 LD(F("Environment variable '%s' is not defined") % name);
86 return none;
87 } else {
88 LD(F("Environment variable '%s' is '%s'") % name % value);
89 return utils::make_optional(std::string(value));
90 }
91 }
92
93
94 /// Gets the value of an environment variable with a default fallback.
95 ///
96 /// \param name The name of the environment variable to query.
97 /// \param default_value The value to return if the variable is not defined.
98 ///
99 /// \return The value of the environment variable.
100 std::string
getenv_with_default(const std::string & name,const std::string & default_value)101 utils::getenv_with_default(const std::string& name,
102 const std::string& default_value)
103 {
104 const char* value = std::getenv(name.c_str());
105 if (value == NULL) {
106 LD(F("Environment variable '%s' is not defined; using default '%s'") %
107 name % default_value);
108 return default_value;
109 } else {
110 LD(F("Environment variable '%s' is '%s'") % name % value);
111 return value;
112 }
113 }
114
115
116 /// Sets the value of an environment variable.
117 ///
118 /// \param name The name of the environment variable to set.
119 /// \param val The value to set the environment variable to. May be empty.
120 ///
121 /// \throw std::runtime_error If there is an error setting the environment
122 /// variable.
123 void
setenv(const std::string & name,const std::string & val)124 utils::setenv(const std::string& name, const std::string& val)
125 {
126 LD(F("Setting environment variable '%s' to '%s'") % name % val);
127 #if defined(HAVE_SETENV)
128 if (::setenv(name.c_str(), val.c_str(), 1) == -1) {
129 const int original_errno = errno;
130 throw std::runtime_error(F("Failed to set environment variable '%s' to "
131 "'%s': %s") %
132 name % val % std::strerror(original_errno));
133 }
134 #elif defined(HAVE_PUTENV)
135 if (::putenv((F("%s=%s") % name % val).c_str()) == -1) {
136 const int original_errno = errno;
137 throw std::runtime_error(F("Failed to set environment variable '%s' to "
138 "'%s': %s") %
139 name % val % std::strerror(original_errno));
140 }
141 #else
142 # error "Don't know how to set an environment variable."
143 #endif
144 }
145
146
147 /// Unsets an environment variable.
148 ///
149 /// \param name The name of the environment variable to unset.
150 ///
151 /// \throw std::runtime_error If there is an error unsetting the environment
152 /// variable.
153 void
unsetenv(const std::string & name)154 utils::unsetenv(const std::string& name)
155 {
156 LD(F("Unsetting environment variable '%s'") % name);
157 #if defined(HAVE_UNSETENV)
158 if (::unsetenv(name.c_str()) == -1) {
159 const int original_errno = errno;
160 throw std::runtime_error(F("Failed to unset environment variable "
161 "'%s'") %
162 name % std::strerror(original_errno));
163 }
164 #elif defined(HAVE_PUTENV)
165 if (::putenv((F("%s=") % name).c_str()) == -1) {
166 const int original_errno = errno;
167 throw std::runtime_error(F("Failed to unset environment variable "
168 "'%s'") %
169 name % std::strerror(original_errno));
170 }
171 #else
172 # error "Don't know how to unset an environment variable."
173 #endif
174 }
175