/*
* Copyright (C) 1997-2000 Matt Newman <[email protected]>
* Copyright (C) 2000 Ajuba Solutions
*
* TLS (aka SSL) Channel - can be layered on any bi-directional
* Tcl_Channel (Note: Requires Trf Core Patch)
*
* This was built from scratch based upon observation of OpenSSL 0.9.2B
*
* Addition credit is due for Andreas Kupries ([email protected]), for
* providing the Tcl_ReplaceChannel mechanism and working closely with me
* to enhance it to support full fileevent semantics.
*
* Also work done by the follow people provided the impetus to do this "right":
* tclSSL (Colin McCormack, Shared Technology)
* SSLtcl (Peter Antman)
*
*/
#include "tlsInt.h"
/*
* Forward declarations
*/
static void TlsChannelHandlerTimer(void *clientData);
/*
*-------------------------------------------------------------------
*
* TlsBlockModeProc --
*
* This procedure is invoked by the generic IO level
* to set blocking and nonblocking modes
*
* Results:
* 0 if successful or POSIX error code if failed.
*
* Side effects:
* Sets the device into blocking or nonblocking mode.
*
*-------------------------------------------------------------------
*/
static int TlsBlockModeProc(void *instanceData, int mode) {
State *statePtr = (State *) instanceData;
if (mode == TCL_MODE_NONBLOCKING) {
statePtr->flags |= TLS_TCL_ASYNC;
} else {
statePtr->flags &= ~(TLS_TCL_ASYNC);
}
return(0);
}
/*
*-------------------------------------------------------------------
*
* TlsClose2Proc --
*
* This procedure is invoked by the generic IO level to perform
* channel-type-specific cleanup when a SSL socket based channel
* is closed.
*
* Note: we leave the underlying socket alone, is this right?
*
* Results:
* 0 if successful or POSIX error code if failed.
*
* Side effects:
* Closes the socket of the channel.
*
*-------------------------------------------------------------------
*/
#if TCL_MAJOR_VERSION > 8
# define TlsCloseProc NULL /* No longer neccessary in Tcl 9 */
#else
static int TlsCloseProc(
void *instanceData,
TCL_UNUSED(Tcl_Interp *))
{
State *statePtr = (State *)instanceData;
dprintf("TlsCloseProc(%p)", statePtr);
Tls_Clean(statePtr);
Tcl_EventuallyFree(statePtr, Tls_Free);
return TCL_OK;
}
#endif
static int TlsClose2Proc(
void *instanceData, /* The socket state. */
Tcl_Interp *interp, /* For errors - can be NULL. */
int flags) /* Flags to close read and/or write side of channel */
{
State *statePtr = (State *)instanceData;
dprintf("TlsClose2Proc(%p)", statePtr);
if ((flags&(TCL_CLOSE_READ|TCL_CLOSE_WRITE))) {
return EINVAL;
}
Tls_Clean(statePtr);
Tcl_EventuallyFree(statePtr, Tls_Free);
return TCL_OK;
}
/*
*------------------------------------------------------*
*
* Tls_WaitForConnect --
*
* Result:
* 0 if successful, -1 if failed.
*
* Side effects:
* Issues SSL_accept or SSL_connect
*
*------------------------------------------------------*
*/
int Tls_WaitForConnect(State *statePtr, int *errorCodePtr, int handshakeFailureIsPermanent) {
unsigned long backingError;
int err, rc;
int bioShouldRetry;
dprintf("WaitForConnect(%p)", statePtr);
dprintFlags(statePtr);
if (!(statePtr->flags & TLS_TCL_INIT)) {
dprintf("Tls_WaitForConnect called on already initialized channel -- returning with immediate success");
*errorCodePtr = 0;
return(0);
}
if (statePtr->flags & TLS_TCL_HANDSHAKE_FAILED) {
/*
* Different types of operations have different requirements
* SSL being established
*/
if (handshakeFailureIsPermanent) {
dprintf("Asked to wait for a TLS handshake that has already failed. Returning fatal error");
*errorCodePtr = ECONNABORTED;
} else {
dprintf("Asked to wait for a TLS handshake that has already failed. Returning soft error");
*errorCodePtr = ECONNRESET;
}
return(-1);
}
for (;;) {
/* Not initialized yet! */
if (statePtr->flags & TLS_TCL_SERVER) {
dprintf("Calling SSL_accept()");
err = SSL_accept(statePtr->ssl);
} else {
dprintf("Calling SSL_connect()");
err = SSL_connect(statePtr->ssl);
}
if (err > 0) {
dprintf("That seems to have gone okay");
err = BIO_flush(statePtr->bio);
if (err <= 0) {
dprintf("Flushing the lower layers failed, this will probably terminate this session");
}
}
rc = SSL_get_error(statePtr->ssl, err);
dprintf("Got error: %i (rc = %i)", err, rc);
bioShouldRetry = 0;
if (err <= 0) {
if (rc == SSL_ERROR_WANT_CONNECT || rc == SSL_ERROR_WANT_ACCEPT || rc == SSL_ERROR_WANT_READ || rc == SSL_ERROR_WANT_WRITE) {
bioShouldRetry = 1;
} else if (BIO_should_retry(statePtr->bio)) {
bioShouldRetry = 1;
} else if (rc == SSL_ERROR_SYSCALL && Tcl_GetErrno() == EAGAIN) {
bioShouldRetry = 1;
}
} else {
if (!SSL_is_init_finished(statePtr->ssl)) {
bioShouldRetry = 1;
}
}
if (bioShouldRetry) {
dprintf("The I/O did not complete -- but we should try it again");
if (statePtr->flags & TLS_TCL_ASYNC) {
dprintf("Returning EAGAIN so that it can be retried later");
*errorCodePtr = EAGAIN;
return(-1);
} else {
dprintf("Doing so now");
continue;
}
}
dprintf("We have either completely established the session or completely failed it -- there is no more need to ever retry it though");
break;
}
*errorCodePtr = EINVAL;
switch (rc) {
case SSL_ERROR_NONE:
/* The connection is up, we are done here */
dprintf("The connection is up");
break;
case SSL_ERROR_ZERO_RETURN:
dprintf("SSL_ERROR_ZERO_RETURN: Connect returned an invalid value...")
return(-1);
case SSL_ERROR_SYSCALL:
backingError = ERR_get_error();
if (backingError == 0 && err == 0) {
dprintf("EOF reached")
*errorCodePtr = ECONNRESET;
} else if (backingError == 0 && err == -1) {
dprintf("I/O error occurred (errno = %lu)", (unsigned long) Tcl_GetErrno());
*errorCodePtr = Tcl_GetErrno();
if (*errorCodePtr == ECONNRESET) {
*errorCodePtr = ECONNABORTED;
}
} else {
dprintf("I/O error occurred (backingError = %lu)", backingError);
*errorCodePtr = backingError;
if (*errorCodePtr == ECONNRESET) {
*errorCodePtr = ECONNABORTED;
}
}
statePtr->flags |= TLS_TCL_HANDSHAKE_FAILED;
return -1;
case SSL_ERROR_SSL:
dprintf("Got permanent fatal SSL error, aborting immediately");
Tls_Error(statePtr, (char *)ERR_reason_error_string(ERR_get_error()));
statePtr->flags |= TLS_TCL_HANDSHAKE_FAILED;
*errorCodePtr = ECONNABORTED;
return(-1);
case SSL_ERROR_WANT_CONNECT:
case SSL_ERROR_WANT_ACCEPT:
case SSL_ERROR_WANT_X509_LOOKUP:
default:
dprintf("We got a confusing reply: %i", rc);
*errorCodePtr = Tcl_GetErrno();
dprintf("ERR(%d, %d) ", rc, *errorCodePtr);
return(-1);
}
#if 0
if (statePtr->flags & TLS_TCL_SERVER) {
dprintf("This is an TLS server, checking the certificate for the peer");
err = SSL_get_verify_result(statePtr->ssl);
if (err != X509_V_OK) {
dprintf("Invalid certificate, returning in failure");
Tls_Error(statePtr, (char *)X509_verify_cert_error_string(err));
statePtr->flags |= TLS_TCL_HANDSHAKE_FAILED;
*errorCodePtr = ECONNABORTED;
return(-1);
}
}
#endif
dprintf("Removing the \"TLS_TCL_INIT\" flag since we have completed the handshake");
statePtr->flags &= ~TLS_TCL_INIT;
dprintf("Returning in success");
*errorCodePtr = 0;
return 0;
}
/*
*-------------------------------------------------------------------
*
* TlsInputProc --
*
* This procedure is invoked by the generic IO level
* to read input from a SSL socket based channel.
*
* Results:
* Returns the number of bytes read or -1 on error. Sets errorCodePtr
* to a POSIX error code if an error occurred, or 0 if none.
*
* Side effects:
* Reads input from the input device of the channel.
*
*-------------------------------------------------------------------
*/
static int TlsInputProc(
void *instanceData,
char *buf,
int bufSize,
int *errorCodePtr)
{
unsigned long backingError;
State *statePtr = (State *) instanceData;
int bytesRead;
int tlsConnect;
int err;
*errorCodePtr = 0;
dprintf("BIO_read(%d)", bufSize);
if (statePtr->flags & TLS_TCL_CALLBACK) {
/* don't process any bytes while verify callback is running */
dprintf("Callback is running, reading 0 bytes");
return(0);
}
dprintf("Calling Tls_WaitForConnect");
tlsConnect = Tls_WaitForConnect(statePtr, errorCodePtr, 0);
if (tlsConnect < 0) {
dprintf("Got an error waiting to connect (tlsConnect = %i, *errorCodePtr = %i)", tlsConnect, *errorCodePtr);
bytesRead = -1;
if (*errorCodePtr == ECONNRESET) {
dprintf("Got connection reset");
/* Soft EOF */
*errorCodePtr = 0;
bytesRead = 0;
}
return(bytesRead);
}
/*
* We need to clear the SSL error stack now because we sometimes reach
* this function with leftover errors in the stack. If BIO_read
* returns -1 and intends EAGAIN, there is a leftover error, it will be
* misconstrued as an error, not EAGAIN.
*
* Alternatively, we may want to handle the <0 return codes from
* BIO_read specially (as advised in the RSA docs). TLS's lower level BIO
* functions play with the retry flags though, and this seems to work
* correctly. Similar fix in TlsOutputProc. - hobbs
*/
ERR_clear_error();
bytesRead = BIO_read(statePtr->bio, buf, bufSize);
dprintf("BIO_read -> %d", bytesRead);
err = SSL_get_error(statePtr->ssl, bytesRead);
#if 0
if (bytesRead <= 0) {
if (BIO_should_retry(statePtr->bio)) {
dprintf("I/O failed, will retry based on EAGAIN");
*errorCodePtr = EAGAIN;
}
}
#endif
switch (err) {
case SSL_ERROR_NONE:
dprintBuffer(buf, bytesRead);
break;
case SSL_ERROR_SSL:
dprintf("SSL negotiation error, indicating that the connection has been aborted");
Tls_Error(statePtr, TCLTLS_SSL_ERROR(statePtr->ssl, bytesRead));
*errorCodePtr = ECONNABORTED;
bytesRead = -1;
break;
case SSL_ERROR_SYSCALL:
backingError = ERR_get_error();
if (backingError == 0 && bytesRead == 0) {
dprintf("EOF reached")
*errorCodePtr = 0;
bytesRead = 0;
} else if (backingError == 0 && bytesRead == -1) {
dprintf("I/O error occurred (errno = %lu)", (unsigned long) Tcl_GetErrno());
*errorCodePtr = Tcl_GetErrno();
bytesRead = -1;
} else {
dprintf("I/O error occurred (backingError = %lu)", backingError);
*errorCodePtr = backingError;
bytesRead = -1;
}
break;
case SSL_ERROR_ZERO_RETURN:
dprintf("Got SSL_ERROR_ZERO_RETURN, this means an EOF has been reached");
bytesRead = 0;
*errorCodePtr = 0;
break;
case SSL_ERROR_WANT_READ:
dprintf("Got SSL_ERROR_WANT_READ, mapping this to EAGAIN");
bytesRead = -1;
*errorCodePtr = EAGAIN;
break;
default:
dprintf("Unknown error (err = %i), mapping to EOF", err);
*errorCodePtr = 0;
bytesRead = 0;
break;
}
dprintf("Input(%d) -> %d [%d]", bufSize, bytesRead, *errorCodePtr);
return bytesRead;
}
/*
*-------------------------------------------------------------------
*
* TlsOutputProc --
*
* This procedure is invoked by the generic IO level
* to write output to a SSL socket based channel.
*
* Results:
* Returns the number of bytes written or -1 on error. Sets errorCodePtr
* to a POSIX error code if an error occurred, or 0 if none.
*
* Side effects:
* Writes output on the output device of the channel.
*
*-------------------------------------------------------------------
*/
static int TlsOutputProc(
void *instanceData,
const char *buf,
int toWrite,
int *errorCodePtr)
{
unsigned long backingError;
State *statePtr = (State *) instanceData;
int written, err;
int tlsConnect;
*errorCodePtr = 0;
dprintf("BIO_write(%p, %d)", (void *) statePtr, toWrite);
dprintBuffer(buf, toWrite);
if (statePtr->flags & TLS_TCL_CALLBACK) {
dprintf("Don't process output while callbacks are running");
written = -1;
*errorCodePtr = EAGAIN;
return(-1);
}
dprintf("Calling Tls_WaitForConnect");
tlsConnect = Tls_WaitForConnect(statePtr, errorCodePtr, 1);
if (tlsConnect < 0) {
dprintf("Got an error waiting to connect (tlsConnect = %i, *errorCodePtr = %i)", tlsConnect, *errorCodePtr);
written = -1;
if (*errorCodePtr == ECONNRESET) {
dprintf("Got connection reset");
/* Soft EOF */
*errorCodePtr = 0;
written = 0;
}
return(written);
}
if (toWrite == 0) {
dprintf("zero-write");
err = BIO_flush(statePtr->bio);
if (err <= 0) {
dprintf("Flushing failed");
*errorCodePtr = EIO;
written = 0;
return(-1);
}
written = 0;
*errorCodePtr = 0;
return(0);
}
/*
* We need to clear the SSL error stack now because we sometimes reach
* this function with leftover errors in the stack. If BIO_write
* returns -1 and intends EAGAIN, there is a leftover error, it will be
* misconstrued as an error, not EAGAIN.
*
* Alternatively, we may want to handle the <0 return codes from
* BIO_write specially (as advised in the RSA docs). TLS's lower level
* BIO functions play with the retry flags though, and this seems to
* work correctly. Similar fix in TlsInputProc. - hobbs
*/
ERR_clear_error();
written = BIO_write(statePtr->bio, buf, toWrite);
dprintf("BIO_write(%p, %d) -> [%d]", (void *) statePtr, toWrite, written);
err = SSL_get_error(statePtr->ssl, written);
switch (err) {
case SSL_ERROR_NONE:
if (written < 0) {
written = 0;
}
break;
case SSL_ERROR_WANT_WRITE:
dprintf("Got SSL_ERROR_WANT_WRITE, mapping it to EAGAIN");
*errorCodePtr = EAGAIN;
written = -1;
break;
case SSL_ERROR_WANT_READ:
dprintf(" write R BLOCK");
break;
case SSL_ERROR_WANT_X509_LOOKUP:
dprintf(" write X BLOCK");
break;
case SSL_ERROR_ZERO_RETURN:
dprintf(" closed");
written = 0;
*errorCodePtr = 0;
break;
case SSL_ERROR_SYSCALL:
backingError = ERR_get_error();
if (backingError == 0 && written == 0) {
dprintf("EOF reached")
*errorCodePtr = 0;
written = 0;
} else if (backingError == 0 && written == -1) {
dprintf("I/O error occurred (errno = %lu)", (unsigned long) Tcl_GetErrno());
*errorCodePtr = Tcl_GetErrno();
written = -1;
} else {
dprintf("I/O error occurred (backingError = %lu)", backingError);
*errorCodePtr = backingError;
written = -1;
}
break;
case SSL_ERROR_SSL:
Tls_Error(statePtr, TCLTLS_SSL_ERROR(statePtr->ssl, written));
*errorCodePtr = ECONNABORTED;
written = -1;
break;
default:
dprintf("unknown error: %d", err);
break;
}
dprintf("Output(%d) -> %d", toWrite, written);
return(written);
}
/*
*-------------------------------------------------------------------
*
* TlsGetOptionProc --
*
* Gets an option value for a SSL socket based channel, or a
* list of all options and their values.
*
* Results:
* A standard Tcl result. The value of the specified option or a
* list of all options and their values is returned in the
* supplied DString.
*
* Side effects:
* None.
*
*-------------------------------------------------------------------
*/
static int
TlsGetOptionProc(
void *instanceData, /* Socket state. */
Tcl_Interp *interp, /* For errors - can be NULL. */
const char *optionName, /* Name of the option to retrieve the value for, or
* NULL to get all options and their values. */
Tcl_DString *optionValue) /* Where to store the computed value initialized by caller. */
{
State *statePtr = (State *) instanceData;
Tcl_Channel downChan = Tls_GetParent(statePtr, TLS_TCL_FASTPATH);
Tcl_DriverGetOptionProc *getOptionProc;
getOptionProc = Tcl_ChannelGetOptionProc(Tcl_GetChannelType(downChan));
if (getOptionProc != NULL) {
return (*getOptionProc)(Tcl_GetChannelInstanceData(downChan), interp, optionName, optionValue);
} else if (optionName == (char*) NULL) {
/*
* Request is query for all options, this is ok.
*/
return TCL_OK;
}
/*
* Request for a specific option has to fail, we don't have any.
*/
return TCL_ERROR;
}
/*
*-------------------------------------------------------------------
*
* TlsWatchProc --
*
* Initialize the notifier to watch Tcl_Files from this channel.
*
* Results:
* None.
*
* Side effects:
* Sets up the notifier so that a future event on the channel
* will be seen by Tcl.
*
*-------------------------------------------------------------------
*/
static void
TlsWatchProc(
void *instanceData, /* The socket state. */
int mask) /* Events of interest; an OR-ed combination of
* TCL_READABLE, TCL_WRITABLE and TCL_EXCEPTION. */
{
Tcl_Channel downChan;
State *statePtr = (State *) instanceData;
dprintf("TlsWatchProc(0x%x)", mask);
/* Pretend to be dead as long as the verify callback is running.
* Otherwise that callback could be invoked recursively. */
if (statePtr->flags & TLS_TCL_CALLBACK) {
dprintf("Callback is on-going, doing nothing");
return;
}
dprintFlags(statePtr);
downChan = Tls_GetParent(statePtr, TLS_TCL_FASTPATH);
if (statePtr->flags & TLS_TCL_HANDSHAKE_FAILED) {
dprintf("Asked to watch a socket with a failed handshake -- nothing can happen here");
dprintf("Unregistering interest in the lower channel");
(Tcl_GetChannelType(downChan))->watchProc(Tcl_GetChannelInstanceData(downChan), 0);
statePtr->watchMask = 0;
return;
}
statePtr->watchMask = mask;
/* No channel handlers any more. We will be notified automatically
* about events on the channel below via a call to our
* 'TransformNotifyProc'. But we have to pass the interest down now.
* We are allowed to add additional 'interest' to the mask if we want
* to. But this transformation has no such interest. It just passes
* the request down, unchanged.
*/
dprintf("Registering our interest in the lower channel (chan=%p)", (void *) downChan);
(Tcl_GetChannelType(downChan))
->watchProc(Tcl_GetChannelInstanceData(downChan), mask);
/*
* Management of the internal timer.
*/
if (statePtr->timer != (Tcl_TimerToken) NULL) {
dprintf("A timer was found, deleting it");
Tcl_DeleteTimerHandler(statePtr->timer);
statePtr->timer = (Tcl_TimerToken) NULL;
}
if ((mask & TCL_READABLE) &&
((Tcl_InputBuffered(statePtr->self) > 0) || (BIO_ctrl_pending(statePtr->bio) > 0))) {
/*
* There is interest in readable events and we actually have
* data waiting, so generate a timer to flush that.
*/
dprintf("Creating a new timer since data appears to be waiting");
statePtr->timer = Tcl_CreateTimerHandler(TLS_TCL_DELAY, TlsChannelHandlerTimer, statePtr);
}
}
/*
*-------------------------------------------------------------------
*
* TlsGetHandleProc --
*
* Called from Tcl_GetChannelFile to retrieve o/s file handler
* from the SSL socket based channel.
*
* Results:
* The appropriate Tcl_File handle or NULL if none.
*
* Side effects:
* None.
*
*-------------------------------------------------------------------
*/
static int TlsGetHandleProc(
void *instanceData, /* Socket state. */
int direction, /* TCL_READABLE or TCL_WRITABLE */
void **handlePtr) /* Handle associated with the channel */
{
State *statePtr = (State *)instanceData;
return(Tcl_GetChannelHandle(Tls_GetParent(statePtr, TLS_TCL_FASTPATH), direction, handlePtr));
}
/*
*-------------------------------------------------------------------
*
* TlsNotifyProc --
*
* Handler called by Tcl to inform us of activity
* on the underlying channel.
*
* Results:
* Type of event or 0 if failed
*
* Side effects:
* May process the incoming event by itself.
*
*-------------------------------------------------------------------
*/
static int TlsNotifyProc(
void *instanceData, /* Socket state. */
int mask) /* type of event that occurred:
* OR-ed combination of TCL_READABLE or TCL_WRITABLE */
{
State *statePtr = (State *)instanceData;
int errorCode;
/*
* An event occurred in the underlying channel. This
* transformation doesn't process such events thus returns the
* incoming mask unchanged.
*/
if (statePtr->timer != (Tcl_TimerToken) NULL) {
/*
* Delete an existing timer. It was not fired, yet we are
* here, so the channel below generated such an event and we
* don't have to. The renewal of the interest after the
* execution of channel handlers will eventually cause us to
* recreate the timer (in WatchProc).
*/
Tcl_DeleteTimerHandler(statePtr->timer);
statePtr->timer = (Tcl_TimerToken) NULL;
}
if (statePtr->flags & TLS_TCL_CALLBACK) {
dprintf("Returning 0 due to callback");
return 0;
}
dprintf("Calling Tls_WaitForConnect");
errorCode = 0;
if (Tls_WaitForConnect(statePtr, &errorCode, 1) < 0) {
if (errorCode == EAGAIN) {
dprintf("Async flag could be set (didn't check) and errorCode == EAGAIN: Returning 0");
return 0;
}
dprintf("Tls_WaitForConnect returned an error");
}
dprintf("Returning %i", mask);
return(mask);
}
/*
*------------------------------------------------------*
*
* TlsChannelHandlerTimer --
*
* ------------------------------------------------*
* Called by the notifier (-> timer) to flush out
* information waiting in channel buffers.
* ------------------------------------------------*
*
* Side effects:
* As of 'TlsChannelHandler'.
*
* Result:
* None.
*
*------------------------------------------------------*
*/
static void TlsChannelHandlerTimer(void *clientData) {
State *statePtr = (State *)clientData;
int mask = 0;
dprintf("Called");
statePtr->timer = (Tcl_TimerToken) NULL;
if (BIO_wpending(statePtr->bio)) {
dprintf("[chan=%p] BIO writable", statePtr->self);
mask |= TCL_WRITABLE;
}
if (BIO_pending(statePtr->bio)) {
dprintf("[chan=%p] BIO readable", statePtr->self);
mask |= TCL_READABLE;
}
dprintf("Notifying ourselves");
Tcl_NotifyChannel(statePtr->self, mask);
dprintf("Returning");
return;
}
Tcl_Channel Tls_GetParent(State *statePtr, int maskFlags) {
dprintf("Requested to get parent of channel %p", statePtr->self);
if ((statePtr->flags & ~maskFlags) & TLS_TCL_FASTPATH) {
dprintf("Asked to get the parent channel while we are using FastPath -- returning NULL");
return(NULL);
}
return Tcl_GetStackedChannel(statePtr->self);
}
/*
*-------------------------------------------------------------------
*
* Tls_ChannelType --
*
* Return the correct TLS channel driver info
*
* Results:
* The correct channel driver for the current version of Tcl.
*
* Side effects:
* None.
*
*-------------------------------------------------------------------
*/
static const Tcl_ChannelType tlsChannelType = {
"tls", /* Type name */
TCL_CHANNEL_VERSION_5, /* v5 channel */
TlsCloseProc, /* Close proc */
TlsInputProc, /* Input proc */
TlsOutputProc, /* Output proc */
0, /* Seek proc */
0, /* Set option proc */
TlsGetOptionProc, /* Get option proc */
TlsWatchProc, /* Initialize notifier */
TlsGetHandleProc, /* Get OS handles out of channel */
TlsClose2Proc, /* close2proc */
TlsBlockModeProc, /* Set blocking/nonblocking mode*/
0, /* Flush proc */
TlsNotifyProc, /* Handling of events bubbling up */
0, /* Wide seek proc */
NULL, /* Thread action */
NULL /* Truncate */
};
const Tcl_ChannelType *Tls_ChannelType(void) {
return &tlsChannelType;
}