xpcom/threads/nsEnvironment.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "nsEnvironment.h"
   8 #include "prenv.h"
   9 #include "nsBaseHashtable.h"
  10 #include "nsHashKeys.h"
  11 #include "nsPromiseFlatString.h"
  12 #include "nsDependentString.h"
  13 #include "nsNativeCharsetUtils.h"
  14 #include "mozilla/Printf.h"
  15
  16 using namespace mozilla;
  17
  18 NS_IMPL_ISUPPORTS(nsEnvironment, nsIEnvironment)
  19
  20 nsresult nsEnvironment::Create(nsISupports* aOuter, REFNSIID aIID,
  21                                void** aResult) {
  22   nsresult rv;
  23   *aResult = nullptr;
  24
  25   if (aOuter) {
  26     return NS_ERROR_NO_AGGREGATION;
  27   }
  28
  29   nsEnvironment* obj = new nsEnvironment();
  30
  31   rv = obj->QueryInterface(aIID, aResult);
  32   if (NS_FAILED(rv)) {
  33     delete obj;
  34   }
  35   return rv;
  36 }
  37
  38 nsEnvironment::~nsEnvironment() = default;
  39
  40 NS_IMETHODIMP
  41 nsEnvironment::Exists(const nsAString& aName, bool* aOutValue) {
  42   nsAutoCString nativeName;
  43   nsresult rv = NS_CopyUnicodeToNative(aName, nativeName);
  44   if (NS_WARN_IF(NS_FAILED(rv))) {
  45     return rv;
  46   }
  47
  48   nsAutoCString nativeVal;
  49 #if defined(XP_UNIX)
  50   /* For Unix/Linux platforms we follow the Unix definition:
  51    * An environment variable exists when |getenv()| returns a non-nullptr
  52    * value. An environment variable does not exist when |getenv()| returns
  53    * nullptr.
  54    */
  55   const char* value = PR_GetEnv(nativeName.get());
  56   *aOutValue = value && *value;
  57 #else
  58   /* For non-Unix/Linux platforms we have to fall back to a
  59    * "portable" definition (which is incorrect for Unix/Linux!!!!)
  60    * which simply checks whether the string returned by |Get()| is empty
  61    * or not.
  62    */
  63   nsAutoString value;
  64   Get(aName, value);
  65   *aOutValue = !value.IsEmpty();
  66 #endif /* XP_UNIX */
  67
  68   return NS_OK;
  69 }
  70
  71 NS_IMETHODIMP
  72 nsEnvironment::Get(const nsAString& aName, nsAString& aOutValue) {
  73   nsAutoCString nativeName;
  74   nsresult rv = NS_CopyUnicodeToNative(aName, nativeName);
  75   if (NS_WARN_IF(NS_FAILED(rv))) {
  76     return rv;
  77   }
  78
  79   nsAutoCString nativeVal;
  80   const char* value = PR_GetEnv(nativeName.get());
  81   if (value && *value) {
  82     rv = NS_CopyNativeToUnicode(nsDependentCString(value), aOutValue);
  83   } else {
  84     aOutValue.Truncate();
  85     rv = NS_OK;
  86   }
  87
  88   return rv;
  89 }
  90
  91 /* Environment strings must have static duration; We're gonna leak all of this
  92  * at shutdown: this is by design, caused how Unix/Linux implement environment
  93  * vars.
  94  */
  95
  96 typedef nsBaseHashtableET<nsCharPtrHashKey, char*> EnvEntryType;
  97 typedef nsTHashtable<EnvEntryType> EnvHashType;
  98
  99 static EnvHashType* gEnvHash = nullptr;
 100
 101 static bool EnsureEnvHash() {
 102   if (gEnvHash) {
 103     return true;
 104   }
 105
 106   gEnvHash = new EnvHashType;
 107   if (!gEnvHash) {
 108     return false;
 109   }
 110
 111   return true;
 112 }
 113
 114 NS_IMETHODIMP
 115 nsEnvironment::Set(const nsAString& aName, const nsAString& aValue) {
 116   nsAutoCString nativeName;
 117   nsAutoCString nativeVal;
 118
 119   nsresult rv = NS_CopyUnicodeToNative(aName, nativeName);
 120   if (NS_WARN_IF(NS_FAILED(rv))) {
 121     return rv;
 122   }
 123
 124   rv = NS_CopyUnicodeToNative(aValue, nativeVal);
 125   if (NS_WARN_IF(NS_FAILED(rv))) {
 126     return rv;
 127   }
 128
 129   MutexAutoLock lock(mLock);
 130
 131   if (!EnsureEnvHash()) {
 132     return NS_ERROR_UNEXPECTED;
 133   }
 134
 135   EnvEntryType* entry = gEnvHash->PutEntry(nativeName.get());
 136   if (!entry) {
 137     return NS_ERROR_OUT_OF_MEMORY;
 138   }
 139
 140   SmprintfPointer newData =
 141       mozilla::Smprintf("%s=%s", nativeName.get(), nativeVal.get());
 142   if (!newData) {
 143     return NS_ERROR_OUT_OF_MEMORY;
 144   }
 145
 146   PR_SetEnv(newData.get());
 147   if (entry->GetData()) {
 148     free(entry->GetData());
 149   }
 150   entry->SetData(newData.release());
 151   return NS_OK;
 152 }