1// Copyright 2010 Google Inc. 2// All rights reserved. 3// 4// Redistribution and use in source and binary forms, with or without 5// modification, are permitted provided that the following conditions are 6// met: 7// 8// * Redistributions of source code must retain the above copyright 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 12// documentation and/or other materials provided with the distribution. 13// * Neither the name of Google Inc. nor the names of its contributors 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 19// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 20// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 21// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 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 25// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 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 44using utils::none; 45using utils::optional; 46 47 48extern "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. 57std::map< std::string, std::string > 58utils::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. 80optional< std::string > 81utils::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. 100std::string 101utils::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. 123void 124utils::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. 153void 154utils::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