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-rw-r--r--tools/plink/winhandl.c1303
1 files changed, 683 insertions, 620 deletions
diff --git a/tools/plink/winhandl.c b/tools/plink/winhandl.c
index 06c2a6a07..b15d1f262 100644
--- a/tools/plink/winhandl.c
+++ b/tools/plink/winhandl.c
@@ -1,620 +1,683 @@
-/*
- * 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 */
- enum { EOF_NO, EOF_PENDING, EOF_SENT } outgoingeof;
-
- /*
- * 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;
- } else if (!ctx->busy && bufchain_size(&ctx->queued_data) == 0 &&
- ctx->outgoingeof == EOF_PENDING) {
- CloseHandle(ctx->h);
- ctx->h = INVALID_HANDLE_VALUE;
- ctx->outgoingeof = EOF_SENT;
- }
-}
-
-/* ----------------------------------------------------------------------
- * 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.outgoingeof = EOF_NO;
- 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);
- assert(h->u.o.outgoingeof == EOF_NO);
- bufchain_add(&h->u.o.queued_data, data, len);
- handle_try_output(&h->u.o);
- return bufchain_size(&h->u.o.queued_data);
-}
-
-void handle_write_eof(struct handle *h)
-{
- /*
- * This function is called when we want to proactively send an
- * end-of-file notification on the handle. We can only do this by
- * actually closing the handle - so never call this on a
- * bidirectional handle if we're still interested in its incoming
- * direction!
- */
- assert(h->output);
- if (!h->u.o.outgoingeof == EOF_NO) {
- h->u.o.outgoingeof = EOF_PENDING;
- handle_try_output(&h->u.o);
- }
-}
-
-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;
-}
+/*
+ * 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 */
+};
+
+typedef enum { HT_INPUT, HT_OUTPUT, HT_FOREIGN } HandleType;
+
+/* ----------------------------------------------------------------------
+ * 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 */
+ enum { EOF_NO, EOF_PENDING, EOF_SENT } outgoingeof;
+
+ /*
+ * 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;
+ } else if (!ctx->busy && bufchain_size(&ctx->queued_data) == 0 &&
+ ctx->outgoingeof == EOF_PENDING) {
+ CloseHandle(ctx->h);
+ ctx->h = INVALID_HANDLE_VALUE;
+ ctx->outgoingeof = EOF_SENT;
+ }
+}
+
+/* ----------------------------------------------------------------------
+ * 'Foreign events'. These are handle structures which just contain a
+ * single event object passed to us by another module such as
+ * winnps.c, so that they can make use of our handle_get_events /
+ * handle_got_event mechanism for communicating with application main
+ * loops.
+ */
+struct handle_foreign {
+ /*
+ * 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 */
+
+ /*
+ * Our own data, just consisting of knowledge of who to call back.
+ */
+ void (*callback)(void *);
+ void *ctx;
+};
+
+/* ----------------------------------------------------------------------
+ * Unified code handling both input and output threads.
+ */
+
+struct handle {
+ HandleType type;
+ union {
+ struct handle_generic g;
+ struct handle_input i;
+ struct handle_output o;
+ struct handle_foreign f;
+ } 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->type = HT_INPUT;
+ 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->type = HT_OUTPUT;
+ 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.outgoingeof = EOF_NO;
+ 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;
+}
+
+struct handle *handle_add_foreign_event(HANDLE event,
+ void (*callback)(void *), void *ctx)
+{
+ struct handle *h = snew(struct handle);
+
+ h->type = HT_FOREIGN;
+ h->u.f.h = INVALID_HANDLE_VALUE;
+ h->u.f.ev_to_main = event;
+ h->u.f.ev_from_main = INVALID_HANDLE_VALUE;
+ h->u.f.defunct = TRUE; /* we have no thread in the first place */
+ h->u.f.moribund = FALSE;
+ h->u.f.done = FALSE;
+ h->u.f.privdata = NULL;
+ h->u.f.callback = callback;
+ h->u.f.ctx = ctx;
+ h->u.f.busy = TRUE;
+
+ if (!handles_by_evtomain)
+ handles_by_evtomain = newtree234(handle_cmp_evtomain);
+ add234(handles_by_evtomain, h);
+
+ return h;
+}
+
+int handle_write(struct handle *h, const void *data, int len)
+{
+ assert(h->type == HT_OUTPUT);
+ assert(h->u.o.outgoingeof == EOF_NO);
+ bufchain_add(&h->u.o.queued_data, data, len);
+ handle_try_output(&h->u.o);
+ return bufchain_size(&h->u.o.queued_data);
+}
+
+void handle_write_eof(struct handle *h)
+{
+ /*
+ * This function is called when we want to proactively send an
+ * end-of-file notification on the handle. We can only do this by
+ * actually closing the handle - so never call this on a
+ * bidirectional handle if we're still interested in its incoming
+ * direction!
+ */
+ assert(h->type == HT_OUTPUT);
+ if (!h->u.o.outgoingeof == EOF_NO) {
+ h->u.o.outgoingeof = EOF_PENDING;
+ handle_try_output(&h->u.o);
+ }
+}
+
+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->type == HT_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;
+ }
+
+ switch (h->type) {
+ int backlog;
+
+ case HT_INPUT:
+ 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);
+ }
+ break;
+
+ case HT_OUTPUT:
+ 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);
+ }
+ break;
+
+ case HT_FOREIGN:
+ /* Just call the callback. */
+ h->u.f.callback(h->u.f.ctx);
+ break;
+ }
+}
+
+void handle_unthrottle(struct handle *h, int backlog)
+{
+ assert(h->type == HT_INPUT);
+ handle_throttle(&h->u.i, backlog);
+}
+
+int handle_backlog(struct handle *h)
+{
+ assert(h->type == HT_OUTPUT);
+ return bufchain_size(&h->u.o.queued_data);
+}
+
+void *handle_get_privdata(struct handle *h)
+{
+ return h->u.g.privdata;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-07 21:38:11 +0000