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process: EnvGetter to use libuv #14641

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process: EnvGetter to use libuv #14641

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2968191
process: EnvGetter to use libuv
refack Aug 4, 2017
a3464e6
[sqwsh] correct usage of uv_os_getenv & implement in EnvQuery
refack Nov 21, 2017
ead9c39
[sqwsh] typos & syntax errors
refack Nov 21, 2017
a23bdb5
[sqwsh] on boy
refack Nov 21, 2017
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45 changes: 15 additions & 30 deletions src/node.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -2752,28 +2752,15 @@ static void EnvGetter(Local<Name> property,
if (property->IsSymbol()) {
return info.GetReturnValue().SetUndefined();
}
#ifdef __POSIX__
node::Utf8Value key(isolate, property);
const char* val = getenv(*key);
if (val) {
return info.GetReturnValue().Set(String::NewFromUtf8(isolate, val));
}
#else // _WIN32
node::TwoByteValue key(isolate, property);
WCHAR buffer[32767]; // The maximum size allowed for environment variables.
DWORD result = GetEnvironmentVariableW(reinterpret_cast<WCHAR*>(*key),
buffer,
arraysize(buffer));
// If result >= sizeof buffer the buffer was too small. That should never
// happen. If result == 0 and result != ERROR_SUCCESS the variable was not
// not found.
if ((result > 0 || GetLastError() == ERROR_SUCCESS) &&
result < arraysize(buffer)) {
const uint16_t* two_byte_buffer = reinterpret_cast<const uint16_t*>(buffer);
Local<String> rc = String::NewFromTwoByte(isolate, two_byte_buffer);
return info.GetReturnValue().Set(rc);
// On POSIX there is not explicitly defined size limit, but on Windows
// environment variables have a maximum size limit of 2**15 - 1.
char buffer[32768];
size_t buf_size = sizeof(buffer);
int ret = uv_os_getenv(*key, buffer, &buf_size);

@bnoordhuis bnoordhuis Nov 24, 2017

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You should retry with a bigger buffer when ret == UV_ENOBUFS, otherwise you introduce an arbitrary size restriction on Unices that wasn't there before.

(And also, can you rename it to err for consistency?)

if (!ret) {
return info.GetReturnValue().Set(String::NewFromUtf8(isolate, buffer));
}
#endif
}


Expand Down Expand Up @@ -2802,24 +2789,22 @@ static void EnvQuery(Local<Name> property,
const PropertyCallbackInfo<Integer>& info) {
int32_t rc = -1; // Not found unless proven otherwise.
if (property->IsString()) {
#ifdef __POSIX__
node::Utf8Value key(info.GetIsolate(), property);
if (getenv(*key))
rc = 0;
#else // _WIN32
node::TwoByteValue key(info.GetIsolate(), property);
WCHAR* key_ptr = reinterpret_cast<WCHAR*>(*key);
if (GetEnvironmentVariableW(key_ptr, nullptr, 0) > 0 ||
GetLastError() == ERROR_SUCCESS) {
// We are only interested in existence, so we can keep the buffer small.
char buffer[256];

@cjihrig cjihrig Nov 22, 2017

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If you're only interested in existence, couldn't you go much smaller than 256?

size_t buf_size = sizeof(buffer);
int ret = uv_os_getenv(*key, buffer, &buf_size);
if (ret != UV_ENOENT) {

@bnoordhuis bnoordhuis Nov 24, 2017

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Reads uninitialized memory when ret == UV_ENOBUFS (i.e., buffer too small.)

rc = 0;
if (key_ptr[0] == L'=') {
#ifdef _WIN32
if (key[0] == L'=') {

@bnoordhuis bnoordhuis Nov 24, 2017

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Just '=', not L'='.

// Environment variables that start with '=' are hidden and read-only.
rc = static_cast<int32_t>(v8::ReadOnly) |
static_cast<int32_t>(v8::DontDelete) |
static_cast<int32_t>(v8::DontEnum);
}
}
#endif
}
}
if (rc != -1)
info.GetReturnValue().Set(rc);
Expand Down