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 #include "mozilla/StaticMutex.h"
  16
  17 using namespace mozilla;
  18
  19 NS_IMPL_ISUPPORTS(nsEnvironment, nsIEnvironment)
  20
  21 nsresult nsEnvironment::Create(REFNSIID aIID, void** aResult) {
  22   nsresult rv;
  23   *aResult = nullptr;
  24
  25   nsEnvironment* obj = new nsEnvironment();
  26
  27   rv = obj->QueryInterface(aIID, aResult);
  28   if (NS_FAILED(rv)) {
  29     delete obj;
  30   }
  31   return rv;
  32 }
  33
  34 NS_IMETHODIMP
  35 nsEnvironment::Exists(const nsAString& aName, bool* aOutValue) {
  36   nsAutoCString nativeName;
  37   nsresult rv = NS_CopyUnicodeToNative(aName, nativeName);
  38   if (NS_WARN_IF(NS_FAILED(rv))) {
  39     return rv;
  40   }
  41
  42   nsAutoCString nativeVal;
  43 #if defined(XP_UNIX)
  44   /* For Unix/Linux platforms we follow the Unix definition:
  45    * An environment variable exists when |getenv()| returns a non-nullptr
  46    * value. An environment variable does not exist when |getenv()| returns
  47    * nullptr.
  48    */
  49   const char* value = PR_GetEnv(nativeName.get());
  50   *aOutValue = value && *value;
  51 #else
  52   /* For non-Unix/Linux platforms we have to fall back to a
  53    * "portable" definition (which is incorrect for Unix/Linux!!!!)
  54    * which simply checks whether the string returned by |Get()| is empty
  55    * or not.
  56    */
  57   nsAutoString value;
  58   Get(aName, value);
  59   *aOutValue = !value.IsEmpty();
  60 #endif /* XP_UNIX */
  61
  62   return NS_OK;
  63 }
  64
  65 NS_IMETHODIMP
  66 nsEnvironment::Get(const nsAString& aName, nsAString& aOutValue) {
  67   nsAutoCString nativeName;
  68   nsresult rv = NS_CopyUnicodeToNative(aName, nativeName);
  69   if (NS_WARN_IF(NS_FAILED(rv))) {
  70     return rv;
  71   }
  72
  73   nsAutoCString nativeVal;
  74   const char* value = PR_GetEnv(nativeName.get());
  75   if (value && *value) {
  76     rv = NS_CopyNativeToUnicode(nsDependentCString(value), aOutValue);
  77   } else {
  78     aOutValue.Truncate();
  79     rv = NS_OK;
  80   }
  81
  82   return rv;
  83 }
  84
  85 /* Environment strings must have static duration; We're gonna leak all of this
  86  * at shutdown: this is by design, caused how Unix/Linux implement environment
  87  * vars.
  88  */
  89
  90 typedef nsBaseHashtableET<nsCharPtrHashKey, char*> EnvEntryType;
  91 typedef nsTHashtable<EnvEntryType> EnvHashType;
  92
  93 static StaticMutex gEnvHashMutex;
  94 static EnvHashType* gEnvHash MOZ_GUARDED_BY(gEnvHashMutex) = nullptr;
  95
  96 static EnvHashType* EnsureEnvHash() MOZ_REQUIRES(gEnvHashMutex) {
  97   if (!gEnvHash) {
  98     gEnvHash = new EnvHashType;
  99   }
 100   return gEnvHash;
 101 }
 102
 103 NS_IMETHODIMP
 104 nsEnvironment::Set(const nsAString& aName, const nsAString& aValue) {
 105   nsAutoCString nativeName;
 106   nsAutoCString nativeVal;
 107
 108   nsresult rv = NS_CopyUnicodeToNative(aName, nativeName);
 109   if (NS_WARN_IF(NS_FAILED(rv))) {
 110     return rv;
 111   }
 112
 113   rv = NS_CopyUnicodeToNative(aValue, nativeVal);
 114   if (NS_WARN_IF(NS_FAILED(rv))) {
 115     return rv;
 116   }
 117
 118   StaticMutexAutoLock lock(gEnvHashMutex);
 119   EnvEntryType* entry = EnsureEnvHash()->PutEntry(nativeName.get());
 120   if (!entry) {
 121     return NS_ERROR_OUT_OF_MEMORY;
 122   }
 123
 124   SmprintfPointer newData =
 125       mozilla::Smprintf("%s=%s", nativeName.get(), nativeVal.get());
 126   if (!newData) {
 127     return NS_ERROR_OUT_OF_MEMORY;
 128   }
 129
 130   PR_SetEnv(newData.get());
 131   if (entry->GetData()) {
 132     free(entry->GetData());
 133   }
 134   entry->SetData(newData.release());
 135   return NS_OK;
 136 }