public IChildProcessStateHolder SpawnProcess(
ref ChildProcessStartInfoInternal startInfo,
string resolvedPath,
SafeHandle stdIn,
SafeHandle stdOut,
SafeHandle stdErr)
{
var arguments = startInfo.Arguments;
var environmentVariables = startInfo.EnvironmentVariables;
var workingDirectory = startInfo.WorkingDirectory;
Span <int> fds = stackalloc int[3];
int handleCount = 0;
uint flags = 0;
if (stdIn != null)
{
fds[handleCount++] = stdIn.DangerousGetHandle().ToInt32();
flags |= RequestFlagsRedirectStdin;
}
if (stdOut != null)
{
fds[handleCount++] = stdOut.DangerousGetHandle().ToInt32();
flags |= RequestFlagsRedirectStdout;
}
if (stdErr != null)
{
fds[handleCount++] = stdErr.DangerousGetHandle().ToInt32();
flags |= RequestFlagsRedirectStderr;
}
if (startInfo.CreateNewConsole)
{
flags |= RequestFlagsCreateNewProcessGroup;
}
else
{
Debug.Assert(!startInfo.AllowSignal);
}
// If AttachToCurrentConsole (== !startInfo.AllowSignal), leave the process running after we (the parent) exit.
// After being orphaned (and possibly reparented to the shell), it may continue running or may be terminated by SIGTTIN/SIGTTOU.
if (startInfo.AllowSignal)
{
flags |= RequestFlagsEnableAutoTermination;
}
using var bw = new MyBinaryWriter(InitialBufferCapacity);
var stateHolder = UnixChildProcessState.Create(this, startInfo.AllowSignal);
try
{
bw.Write(stateHolder.State.Token);
bw.Write(flags);
bw.Write(workingDirectory);
bw.Write(resolvedPath);
bw.Write((uint)(arguments.Count + 1));
bw.Write(resolvedPath);
foreach (var x in arguments)
{
bw.Write(x);
}
if (!startInfo.UseCustomEnvironmentVariables)
{
// Send the environment variables of this process to the helper process.
//
// NOTE: We cannot cache or detect updates to the environment block; only the runtime can.
// Concurrently invoking getenv and setenv is a racy operation; therefore the runtime
// employs a process-global lock.
//
// Fortunately, the caller can take a snapshot of environment variables theirselves.
var processEnvVars = Environment.GetEnvironmentVariables();
var envVarCount = processEnvVars.Count;
bw.Write((uint)envVarCount);
var sortedEnvVars = ArrayPool <KeyValuePair <string, string> > .Shared.Rent(envVarCount);
try
{
EnvironmentVariableListUtil.ToSortedKeyValuePairs(processEnvVars, sortedEnvVars);
foreach (var(name, value) in sortedEnvVars.AsSpan <KeyValuePair <string, string> >().Slice(0, envVarCount))
{
bw.WriteEnvironmentVariable(name, value);
}
}
finally
{
ArrayPool <KeyValuePair <string, string> > .Shared.Return(sortedEnvVars);
}
}
else
{
bw.Write((uint)environmentVariables.Length);
foreach (var(name, value) in environmentVariables.Span)
{
bw.WriteEnvironmentVariable(name, value);
}
}
// Work around https://github.com/microsoft/WSL/issues/6490
// On WSL 1, if you call recvmsg multiple times to fully receive data sent with sendmsg,
// the fds will be duplicated for each recvmsg call.
// Send only fixed length of of data with the fds and receive that much data with one recvmsg call.
// That will be safer anyway.
Span <byte> header = stackalloc byte[sizeof(uint) * 2];
if (!BitConverter.TryWriteBytes(header, (uint)UnixHelperProcessCommand.SpawnProcess) ||
!BitConverter.TryWriteBytes(header.Slice(sizeof(uint)), bw.Length))
{
Debug.Fail("Should never fail.");
}
var subchannel = _helperProcess.RentSubchannelAsync(default).AsTask().GetAwaiter().GetResult();
/// <summary>
/// Initializes a new instance of the <see cref="ChildProcessCreationContext"/> class
/// with the environment variables of the current process.
/// </summary>
/// <remarks>
/// (Windows-specific) Duplicates will be removed.
/// This method performs <see cref="StringComparison.Ordinal"/> comparisons and picks the smallest one (uppercase one).
/// Some broken programs (for example, Cygwin) add names that differ only in cases to the environment block.
/// </remarks>
/// <returns>Created instance of the <see cref="ChildProcessCreationContext"/> class.</returns>
public static ChildProcessCreationContext FromProcessEnvironment()
{
var processEnvVars = EnvironmentVariableListUtil.ToSortedDistinctKeyValuePairs(Environment.GetEnvironmentVariables());
return(new ChildProcessCreationContext(processEnvVars.AsMemory()));
}
