diff options
Diffstat (limited to 'tools/plink/winhandl.c')
| -rw-r--r-- | tools/plink/winhandl.c | 1303 |
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; +} |