1// Copyright 2010 The Kyua Authors.
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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
46namespace fs = utils::fs;
47
48using utils::none;
49using utils::optional;
50
51
52extern "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.
61std::map< std::string, std::string >
62utils::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.
84optional< std::string >
85utils::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.
104std::string
105utils::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.
124optional< fs::path >
125utils::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.
149void
150utils::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.
179void
180utils::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