Reintegrate tools from trunk

1 files changed, 596 insertions, 0 deletions

diff --git a/tools/plink/winhandl.c b/tools/plink/winhandl.c
new file mode 100644
index 000000000..dbcab2b2a
--- /dev/null
+++ b/tools/plink/winhandl.c
@@ -0,0 +1,596 @@
+/*

+ * winhandl.c: Module to give Windows front ends the general

+ * ability to deal with consoles, pipes, serial ports, or any other

+ * type of data stream accessed through a Windows API HANDLE rather

+ * than a WinSock SOCKET.

+ *

+ * We do this by spawning a subthread to continuously try to read

+ * from the handle. Every time a read successfully returns some

+ * data, the subthread sets an event object which is picked up by

+ * the main thread, and the main thread then sets an event in

+ * return to instruct the subthread to resume reading.

+ * 

+ * Output works precisely the other way round, in a second

+ * subthread. The output subthread should not be attempting to

+ * write all the time, because it hasn't always got data _to_

+ * write; so the output thread waits for an event object notifying

+ * it to _attempt_ a write, and then it sets an event in return

+ * when one completes.

+ * 

+ * (It's terribly annoying having to spawn a subthread for each

+ * direction of each handle. Technically it isn't necessary for

+ * serial ports, since we could use overlapped I/O within the main

+ * thread and wait directly on the event objects in the OVERLAPPED

+ * structures. However, we can't use this trick for some types of

+ * file handle at all - for some reason Windows restricts use of

+ * OVERLAPPED to files which were opened with the overlapped flag -

+ * and so we must use threads for those. This being the case, it's

+ * simplest just to use threads for everything rather than trying

+ * to keep track of multiple completely separate mechanisms.)

+ */

+

+#include <assert.h>

+

+#include "putty.h"

+

+/* ----------------------------------------------------------------------

+ * Generic definitions.

+ */

+

+/*

+ * Maximum amount of backlog we will allow to build up on an input

+ * handle before we stop reading from it.

+ */

+#define MAX_BACKLOG 32768

+

+struct handle_generic {

+    /*

+     * Initial fields common to both handle_input and handle_output

+     * structures.

+     * 

+     * The three HANDLEs are set up at initialisation time and are

+     * thereafter read-only to both main thread and subthread.

+     * `moribund' is only used by the main thread; `done' is

+     * written by the main thread before signalling to the

+     * subthread. `defunct' and `busy' are used only by the main

+     * thread.

+     */

+    HANDLE h;			       /* the handle itself */

+    HANDLE ev_to_main;		       /* event used to signal main thread */

+    HANDLE ev_from_main;	       /* event used to signal back to us */

+    int moribund;		       /* are we going to kill this soon? */

+    int done;			       /* request subthread to terminate */

+    int defunct;		       /* has the subthread already gone? */

+    int busy;			       /* operation currently in progress? */

+    void *privdata;		       /* for client to remember who they are */

+};

+

+/* ----------------------------------------------------------------------

+ * Input threads.

+ */

+

+/*

+ * Data required by an input thread.

+ */

+struct handle_input {

+    /*

+     * Copy of the handle_generic structure.

+     */

+    HANDLE h;			       /* the handle itself */

+    HANDLE ev_to_main;		       /* event used to signal main thread */

+    HANDLE ev_from_main;	       /* event used to signal back to us */

+    int moribund;		       /* are we going to kill this soon? */

+    int done;			       /* request subthread to terminate */

+    int defunct;		       /* has the subthread already gone? */

+    int busy;			       /* operation currently in progress? */

+    void *privdata;		       /* for client to remember who they are */

+

+    /*

+     * Data set at initialisation and then read-only.

+     */

+    int flags;

+

+    /*

+     * Data set by the input thread before signalling ev_to_main,

+     * and read by the main thread after receiving that signal.

+     */

+    char buffer[4096];		       /* the data read from the handle */

+    DWORD len;			       /* how much data that was */

+    int readerr;		       /* lets us know about read errors */

+

+    /*

+     * Callback function called by this module when data arrives on

+     * an input handle.

+     */

+    handle_inputfn_t gotdata;

+};

+

+/*

+ * The actual thread procedure for an input thread.

+ */

+static DWORD WINAPI handle_input_threadfunc(void *param)

+{

+    struct handle_input *ctx = (struct handle_input *) param;

+    OVERLAPPED ovl, *povl;

+    HANDLE oev;

+    int readret, readlen;

+

+    if (ctx->flags & HANDLE_FLAG_OVERLAPPED) {

+	povl = &ovl;

+	oev = CreateEvent(NULL, TRUE, FALSE, NULL);

+    } else {

+	povl = NULL;

+    }

+

+    if (ctx->flags & HANDLE_FLAG_UNITBUFFER)

+	readlen = 1;

+    else

+	readlen = sizeof(ctx->buffer);

+

+    while (1) {

+	if (povl) {

+	    memset(povl, 0, sizeof(OVERLAPPED));

+	    povl->hEvent = oev;

+	}

+	readret = ReadFile(ctx->h, ctx->buffer,readlen, &ctx->len, povl);

+	if (!readret)

+	    ctx->readerr = GetLastError();

+	else

+	    ctx->readerr = 0;

+	if (povl && !readret && ctx->readerr == ERROR_IO_PENDING) {

+	    WaitForSingleObject(povl->hEvent, INFINITE);

+	    readret = GetOverlappedResult(ctx->h, povl, &ctx->len, FALSE);

+	    if (!readret)

+		ctx->readerr = GetLastError();

+	    else

+		ctx->readerr = 0;

+	}

+

+	if (!readret) {

+	    /*

+	     * Windows apparently sends ERROR_BROKEN_PIPE when a

+	     * pipe we're reading from is closed normally from the

+	     * writing end. This is ludicrous; if that situation

+	     * isn't a natural EOF, _nothing_ is. So if we get that

+	     * particular error, we pretend it's EOF.

+	     */

+	    if (ctx->readerr == ERROR_BROKEN_PIPE)

+		ctx->readerr = 0;

+	    ctx->len = 0;

+	}

+

+	if (readret && ctx->len == 0 &&

+	    (ctx->flags & HANDLE_FLAG_IGNOREEOF))

+	    continue;

+

+	SetEvent(ctx->ev_to_main);

+

+	if (!ctx->len)

+	    break;

+

+	WaitForSingleObject(ctx->ev_from_main, INFINITE);

+	if (ctx->done)

+	    break;		       /* main thread told us to shut down */

+    }

+

+    if (povl)

+	CloseHandle(oev);

+

+    return 0;

+}

+

+/*

+ * This is called after a succcessful read, or from the

+ * `unthrottle' function. It decides whether or not to begin a new

+ * read operation.

+ */

+static void handle_throttle(struct handle_input *ctx, int backlog)

+{

+    if (ctx->defunct)

+	return;

+

+    /*

+     * If there's a read operation already in progress, do nothing:

+     * when that completes, we'll come back here and be in a

+     * position to make a better decision.

+     */

+    if (ctx->busy)

+	return;

+

+    /*

+     * Otherwise, we must decide whether to start a new read based

+     * on the size of the backlog.

+     */

+    if (backlog < MAX_BACKLOG) {

+	SetEvent(ctx->ev_from_main);

+	ctx->busy = TRUE;

+    }

+}

+

+/* ----------------------------------------------------------------------

+ * Output threads.

+ */

+

+/*

+ * Data required by an output thread.

+ */

+struct handle_output {

+    /*

+     * Copy of the handle_generic structure.

+     */

+    HANDLE h;			       /* the handle itself */

+    HANDLE ev_to_main;		       /* event used to signal main thread */

+    HANDLE ev_from_main;	       /* event used to signal back to us */

+    int moribund;		       /* are we going to kill this soon? */

+    int done;			       /* request subthread to terminate */

+    int defunct;		       /* has the subthread already gone? */

+    int busy;			       /* operation currently in progress? */

+    void *privdata;		       /* for client to remember who they are */

+

+    /*

+     * Data set at initialisation and then read-only.

+     */

+    int flags;

+

+    /*

+     * Data set by the main thread before signalling ev_from_main,

+     * and read by the input thread after receiving that signal.

+     */

+    char *buffer;		       /* the data to write */

+    DWORD len;			       /* how much data there is */

+

+    /*

+     * Data set by the input thread before signalling ev_to_main,

+     * and read by the main thread after receiving that signal.

+     */

+    DWORD lenwritten;		       /* how much data we actually wrote */

+    int writeerr;		       /* return value from WriteFile */

+

+    /*

+     * Data only ever read or written by the main thread.

+     */

+    bufchain queued_data;	       /* data still waiting to be written */

+

+    /*

+     * Callback function called when the backlog in the bufchain

+     * drops.

+     */

+    handle_outputfn_t sentdata;

+};

+

+static DWORD WINAPI handle_output_threadfunc(void *param)

+{

+    struct handle_output *ctx = (struct handle_output *) param;

+    OVERLAPPED ovl, *povl;

+    HANDLE oev;

+    int writeret;

+

+    if (ctx->flags & HANDLE_FLAG_OVERLAPPED) {

+	povl = &ovl;

+	oev = CreateEvent(NULL, TRUE, FALSE, NULL);

+    } else {

+	povl = NULL;

+    }

+

+    while (1) {

+	WaitForSingleObject(ctx->ev_from_main, INFINITE);

+	if (ctx->done) {

+	    SetEvent(ctx->ev_to_main);

+	    break;

+	}

+	if (povl) {

+	    memset(povl, 0, sizeof(OVERLAPPED));

+	    povl->hEvent = oev;

+	}

+

+	writeret = WriteFile(ctx->h, ctx->buffer, ctx->len,

+			     &ctx->lenwritten, povl);

+	if (!writeret)

+	    ctx->writeerr = GetLastError();

+	else

+	    ctx->writeerr = 0;

+	if (povl && !writeret && GetLastError() == ERROR_IO_PENDING) {

+	    writeret = GetOverlappedResult(ctx->h, povl,

+					   &ctx->lenwritten, TRUE);

+	    if (!writeret)

+		ctx->writeerr = GetLastError();

+	    else

+		ctx->writeerr = 0;

+	}

+

+	SetEvent(ctx->ev_to_main);

+	if (!writeret)

+	    break;

+    }

+

+    if (povl)

+	CloseHandle(oev);

+

+    return 0;

+}

+

+static void handle_try_output(struct handle_output *ctx)

+{

+    void *senddata;

+    int sendlen;

+

+    if (!ctx->busy && bufchain_size(&ctx->queued_data)) {

+	bufchain_prefix(&ctx->queued_data, &senddata, &sendlen);

+	ctx->buffer = senddata;

+	ctx->len = sendlen;

+	SetEvent(ctx->ev_from_main);

+	ctx->busy = TRUE;

+    }

+}

+

+/* ----------------------------------------------------------------------

+ * Unified code handling both input and output threads.

+ */

+

+struct handle {

+    int output;

+    union {

+	struct handle_generic g;

+	struct handle_input i;

+	struct handle_output o;

+    } u;

+};

+

+static tree234 *handles_by_evtomain;

+

+static int handle_cmp_evtomain(void *av, void *bv)

+{

+    struct handle *a = (struct handle *)av;

+    struct handle *b = (struct handle *)bv;

+

+    if ((unsigned)a->u.g.ev_to_main < (unsigned)b->u.g.ev_to_main)

+	return -1;

+    else if ((unsigned)a->u.g.ev_to_main > (unsigned)b->u.g.ev_to_main)

+	return +1;

+    else

+	return 0;

+}

+

+static int handle_find_evtomain(void *av, void *bv)

+{

+    HANDLE *a = (HANDLE *)av;

+    struct handle *b = (struct handle *)bv;

+

+    if ((unsigned)*a < (unsigned)b->u.g.ev_to_main)

+	return -1;

+    else if ((unsigned)*a > (unsigned)b->u.g.ev_to_main)

+	return +1;

+    else

+	return 0;

+}

+

+struct handle *handle_input_new(HANDLE handle, handle_inputfn_t gotdata,

+				void *privdata, int flags)

+{

+    struct handle *h = snew(struct handle);

+    DWORD in_threadid; /* required for Win9x */

+

+    h->output = FALSE;

+    h->u.i.h = handle;

+    h->u.i.ev_to_main = CreateEvent(NULL, FALSE, FALSE, NULL);

+    h->u.i.ev_from_main = CreateEvent(NULL, FALSE, FALSE, NULL);

+    h->u.i.gotdata = gotdata;

+    h->u.i.defunct = FALSE;

+    h->u.i.moribund = FALSE;

+    h->u.i.done = FALSE;

+    h->u.i.privdata = privdata;

+    h->u.i.flags = flags;

+

+    if (!handles_by_evtomain)

+	handles_by_evtomain = newtree234(handle_cmp_evtomain);

+    add234(handles_by_evtomain, h);

+

+    CreateThread(NULL, 0, handle_input_threadfunc,

+		 &h->u.i, 0, &in_threadid);

+    h->u.i.busy = TRUE;

+

+    return h;

+}

+

+struct handle *handle_output_new(HANDLE handle, handle_outputfn_t sentdata,

+				 void *privdata, int flags)

+{

+    struct handle *h = snew(struct handle);

+    DWORD out_threadid; /* required for Win9x */

+

+    h->output = TRUE;

+    h->u.o.h = handle;

+    h->u.o.ev_to_main = CreateEvent(NULL, FALSE, FALSE, NULL);

+    h->u.o.ev_from_main = CreateEvent(NULL, FALSE, FALSE, NULL);

+    h->u.o.busy = FALSE;

+    h->u.o.defunct = FALSE;

+    h->u.o.moribund = FALSE;

+    h->u.o.done = FALSE;

+    h->u.o.privdata = privdata;

+    bufchain_init(&h->u.o.queued_data);

+    h->u.o.sentdata = sentdata;

+    h->u.o.flags = flags;

+

+    if (!handles_by_evtomain)

+	handles_by_evtomain = newtree234(handle_cmp_evtomain);

+    add234(handles_by_evtomain, h);

+

+    CreateThread(NULL, 0, handle_output_threadfunc,

+		 &h->u.o, 0, &out_threadid);

+

+    return h;

+}

+

+int handle_write(struct handle *h, const void *data, int len)

+{

+    assert(h->output);

+    bufchain_add(&h->u.o.queued_data, data, len);

+    handle_try_output(&h->u.o);

+    return bufchain_size(&h->u.o.queued_data);

+}

+

+HANDLE *handle_get_events(int *nevents)

+{

+    HANDLE *ret;

+    struct handle *h;

+    int i, n, size;

+

+    /*

+     * Go through our tree counting the handle objects currently

+     * engaged in useful activity.

+     */

+    ret = NULL;

+    n = size = 0;

+    if (handles_by_evtomain) {

+	for (i = 0; (h = index234(handles_by_evtomain, i)) != NULL; i++) {

+	    if (h->u.g.busy) {

+		if (n >= size) {

+		    size += 32;

+		    ret = sresize(ret, size, HANDLE);

+		}

+		ret[n++] = h->u.g.ev_to_main;

+	    }

+	}

+    }

+

+    *nevents = n;

+    return ret;

+}

+

+static void handle_destroy(struct handle *h)

+{

+    if (h->output)

+	bufchain_clear(&h->u.o.queued_data);

+    CloseHandle(h->u.g.ev_from_main);

+    CloseHandle(h->u.g.ev_to_main);

+    del234(handles_by_evtomain, h);

+    sfree(h);

+}

+

+void handle_free(struct handle *h)

+{

+    /*

+     * If the handle is currently busy, we cannot immediately free

+     * it. Instead we must wait until it's finished its current

+     * operation, because otherwise the subthread will write to

+     * invalid memory after we free its context from under it.

+     */

+    assert(h && !h->u.g.moribund);

+    if (h->u.g.busy) {

+	/*

+	 * Just set the moribund flag, which will be noticed next

+	 * time an operation completes.

+	 */

+	h->u.g.moribund = TRUE;

+    } else if (h->u.g.defunct) {

+	/*

+	 * There isn't even a subthread; we can go straight to

+	 * handle_destroy.

+	 */

+	handle_destroy(h);

+    } else {

+	/*

+	 * The subthread is alive but not busy, so we now signal it

+	 * to die. Set the moribund flag to indicate that it will

+	 * want destroying after that.

+	 */

+	h->u.g.moribund = TRUE;

+	h->u.g.done = TRUE;

+	h->u.g.busy = TRUE;

+	SetEvent(h->u.g.ev_from_main);

+    }

+}

+

+void handle_got_event(HANDLE event)

+{

+    struct handle *h;

+

+    assert(handles_by_evtomain);

+    h = find234(handles_by_evtomain, &event, handle_find_evtomain);

+    if (!h) {

+	/*

+	 * This isn't an error condition. If two or more event

+	 * objects were signalled during the same select operation,

+	 * and processing of the first caused the second handle to

+	 * be closed, then it will sometimes happen that we receive

+	 * an event notification here for a handle which is already

+	 * deceased. In that situation we simply do nothing.

+	 */

+	return;

+    }

+

+    if (h->u.g.moribund) {

+	/*

+	 * A moribund handle is already treated as dead from the

+	 * external user's point of view, so do nothing with the

+	 * actual event. Just signal the thread to die if

+	 * necessary, or destroy the handle if not.

+	 */

+	if (h->u.g.done) {

+	    handle_destroy(h);

+	} else {

+	    h->u.g.done = TRUE;

+	    h->u.g.busy = TRUE;

+	    SetEvent(h->u.g.ev_from_main);

+	}

+	return;

+    }

+

+    if (!h->output) {

+	int backlog;

+

+	h->u.i.busy = FALSE;

+

+	/*

+	 * A signal on an input handle means data has arrived.

+	 */

+	if (h->u.i.len == 0) {

+	    /*

+	     * EOF, or (nearly equivalently) read error.

+	     */

+	    h->u.i.gotdata(h, NULL, -h->u.i.readerr);

+	    h->u.i.defunct = TRUE;

+	} else {

+	    backlog = h->u.i.gotdata(h, h->u.i.buffer, h->u.i.len);

+	    handle_throttle(&h->u.i, backlog);

+	}

+    } else {

+	h->u.o.busy = FALSE;

+

+	/*

+	 * A signal on an output handle means we have completed a

+	 * write. Call the callback to indicate that the output

+	 * buffer size has decreased, or to indicate an error.

+	 */

+	if (h->u.o.writeerr) {

+	    /*

+	     * Write error. Send a negative value to the callback,

+	     * and mark the thread as defunct (because the output

+	     * thread is terminating by now).

+	     */

+	    h->u.o.sentdata(h, -h->u.o.writeerr);

+	    h->u.o.defunct = TRUE;

+	} else {

+	    bufchain_consume(&h->u.o.queued_data, h->u.o.lenwritten);

+	    h->u.o.sentdata(h, bufchain_size(&h->u.o.queued_data));

+	    handle_try_output(&h->u.o);

+	}

+    }

+}

+

+void handle_unthrottle(struct handle *h, int backlog)

+{

+    assert(!h->output);

+    handle_throttle(&h->u.i, backlog);

+}

+

+int handle_backlog(struct handle *h)

+{

+    assert(h->output);

+    return bufchain_size(&h->u.o.queued_data);

+}

+

+void *handle_get_privdata(struct handle *h)

+{

+    return h->u.g.privdata;

+}