1 // Copyright 2010 The Kyua Authors.
2 // All rights reserved.
3 //
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5 // modification, are permitted provided that the following conditions are
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7 //
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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
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16 //
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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/fs/exceptions.hpp"
42 #include "utils/fs/path.hpp"
43 #include "utils/logging/macros.hpp"
44 #include "utils/optional.ipp"
45
46 namespace fs = utils::fs;
47
48 using utils::none;
49 using utils::optional;
50
51
52 extern "C" {
53 extern char** environ;
54 }
55
56
57 /// Gets all environment variables.
58 ///
59 /// \return A mapping of (name, value) pairs describing the environment
60 /// variables.
61 std::map< std::string, std::string >
getallenv(void)62 utils::getallenv(void)
63 {
64 std::map< std::string, std::string > allenv;
65 for (char** envp = environ; *envp != NULL; envp++) {
66 const std::string oneenv = *envp;
67 const std::string::size_type pos = oneenv.find('=');
68 const std::string name = oneenv.substr(0, pos);
69 const std::string value = oneenv.substr(pos + 1);
70
71 PRE(allenv.find(name) == allenv.end());
72 allenv[name] = value;
73 }
74 return allenv;
75 }
76
77
78 /// Gets the value of an environment variable.
79 ///
80 /// \param name The name of the environment variable to query.
81 ///
82 /// \return The value of the environment variable if it is defined, or none
83 /// otherwise.
84 optional< std::string >
getenv(const std::string & name)85 utils::getenv(const std::string& name)
86 {
87 const char* value = std::getenv(name.c_str());
88 if (value == NULL) {
89 LD(F("Environment variable '%s' is not defined") % name);
90 return none;
91 } else {
92 LD(F("Environment variable '%s' is '%s'") % name % value);
93 return utils::make_optional(std::string(value));
94 }
95 }
96
97
98 /// Gets the value of an environment variable with a default fallback.
99 ///
100 /// \param name The name of the environment variable to query.
101 /// \param default_value The value to return if the variable is not defined.
102 ///
103 /// \return The value of the environment variable.
104 std::string
getenv_with_default(const std::string & name,const std::string & default_value)105 utils::getenv_with_default(const std::string& name,
106 const std::string& default_value)
107 {
108 const char* value = std::getenv(name.c_str());
109 if (value == NULL) {
110 LD(F("Environment variable '%s' is not defined; using default '%s'") %
111 name % default_value);
112 return default_value;
113 } else {
114 LD(F("Environment variable '%s' is '%s'") % name % value);
115 return value;
116 }
117 }
118
119
120 /// Gets the value of the HOME environment variable with path validation.
121 ///
122 /// \return The value of the HOME environment variable if it is a valid path;
123 /// none if it is not defined or if it contains an invalid path.
124 optional< fs::path >
get_home(void)125 utils::get_home(void)
126 {
127 const optional< std::string > home = utils::getenv("HOME");
128 if (home) {
129 try {
130 return utils::make_optional(fs::path(home.get()));
131 } catch (const fs::error& e) {
132 LW(F("Invalid value '%s' in HOME environment variable: %s") %
133 home.get() % e.what());
134 return none;
135 }
136 } else {
137 return none;
138 }
139 }
140
141
142 /// Sets the value of an environment variable.
143 ///
144 /// \param name The name of the environment variable to set.
145 /// \param val The value to set the environment variable to. May be empty.
146 ///
147 /// \throw std::runtime_error If there is an error setting the environment
148 /// variable.
149 void
setenv(const std::string & name,const std::string & val)150 utils::setenv(const std::string& name, const std::string& val)
151 {
152 LD(F("Setting environment variable '%s' to '%s'") % name % val);
153 #if defined(HAVE_SETENV)
154 if (::setenv(name.c_str(), val.c_str(), 1) == -1) {
155 const int original_errno = errno;
156 throw std::runtime_error(F("Failed to set environment variable '%s' to "
157 "'%s': %s") %
158 name % val % std::strerror(original_errno));
159 }
160 #elif defined(HAVE_PUTENV)
161 if (::putenv((F("%s=%s") % name % val).c_str()) == -1) {
162 const int original_errno = errno;
163 throw std::runtime_error(F("Failed to set environment variable '%s' to "
164 "'%s': %s") %
165 name % val % std::strerror(original_errno));
166 }
167 #else
168 # error "Don't know how to set an environment variable."
169 #endif
170 }
171
172
173 /// Unsets an environment variable.
174 ///
175 /// \param name The name of the environment variable to unset.
176 ///
177 /// \throw std::runtime_error If there is an error unsetting the environment
178 /// variable.
179 void
unsetenv(const std::string & name)180 utils::unsetenv(const std::string& name)
181 {
182 LD(F("Unsetting environment variable '%s'") % name);
183 #if defined(HAVE_UNSETENV)
184 if (::unsetenv(name.c_str()) == -1) {
185 const int original_errno = errno;
186 throw std::runtime_error(F("Failed to unset environment variable "
187 "'%s'") %
188 name % std::strerror(original_errno));
189 }
190 #elif defined(HAVE_PUTENV)
191 if (::putenv((F("%s=") % name).c_str()) == -1) {
192 const int original_errno = errno;
193 throw std::runtime_error(F("Failed to unset environment variable "
194 "'%s'") %
195 name % std::strerror(original_errno));
196 }
197 #else
198 # error "Don't know how to unset an environment variable."
199 #endif
200 }
201