X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=blobdiff_plain;f=windows%2Fwinhandl.c;h=cfd6298747e6f1805b087509ff8e56d50931a274;hb=24c9cfc800c5e81819d80fd3eda953f950e263d6;hp=fc641812a1b024a943f3d9318bb17aa4c3912add;hpb=17bc6545327276030423ada8a95dc45f365bf2ad;p=PuTTY.git diff --git a/windows/winhandl.c b/windows/winhandl.c index fc641812..cfd62987 100644 --- a/windows/winhandl.c +++ b/windows/winhandl.c @@ -16,6 +16,17 @@ * 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 @@ -54,6 +65,8 @@ struct handle_generic { void *privdata; /* for client to remember who they are */ }; +typedef enum { HT_INPUT, HT_OUTPUT, HT_FOREIGN } HandleType; + /* ---------------------------------------------------------------------- * Input threads. */ @@ -85,7 +98,7 @@ struct handle_input { */ char buffer[4096]; /* the data read from the handle */ DWORD len; /* how much data that was */ - int readret; /* lets us know about read errors */ + int readerr; /* lets us know about read errors */ /* * Callback function called by this module when data arrives on @@ -101,37 +114,88 @@ static DWORD WINAPI handle_input_threadfunc(void *param) { struct handle_input *ctx = (struct handle_input *) param; OVERLAPPED ovl, *povl; + HANDLE oev; + int readret, readlen, finished; - if (ctx->flags & HANDLE_FLAG_OVERLAPPED) + if (ctx->flags & HANDLE_FLAG_OVERLAPPED) { povl = &ovl; - else + 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) + if (povl) { memset(povl, 0, sizeof(OVERLAPPED)); - ctx->readret = ReadFile(ctx->h, ctx->buffer, sizeof(ctx->buffer), - &ctx->len, povl); - if (povl && !ctx->readret && GetLastError() == ERROR_IO_PENDING) - ctx->readret = GetOverlappedResult(ctx->h, povl, &ctx->len, TRUE); + 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 (!ctx->readret) + 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 (ctx->readret && ctx->len == 0 && + if (readret && ctx->len == 0 && (ctx->flags & HANDLE_FLAG_IGNOREEOF)) continue; + /* + * If we just set ctx->len to 0, that means the read operation + * has returned end-of-file. Telling that to the main thread + * will cause it to set its 'defunct' flag and dispose of the + * handle structure at the next opportunity, in which case we + * mustn't touch ctx at all after the SetEvent. (Hence we do + * even _this_ check before the SetEvent.) + */ + finished = (ctx->len == 0); + SetEvent(ctx->ev_to_main); - if (!ctx->len) + if (finished) break; WaitForSingleObject(ctx->ev_from_main, INFINITE); - if (ctx->done) - break; /* main thread told us to shut down */ + if (ctx->done) { + /* + * The main thread has asked us to shut down. Send back an + * event indicating that we've done so. Hereafter we must + * not touch ctx at all, because the main thread might + * have freed it. + */ + SetEvent(ctx->ev_to_main); + break; + } } + if (povl) + CloseHandle(oev); + return 0; } @@ -200,12 +264,13 @@ struct handle_output { * and read by the main thread after receiving that signal. */ DWORD lenwritten; /* how much data we actually wrote */ - int writeret; /* return value from WriteFile */ + 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 @@ -218,31 +283,64 @@ 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) + if (ctx->flags & HANDLE_FLAG_OVERLAPPED) { povl = &ovl; - else + oev = CreateEvent(NULL, TRUE, FALSE, NULL); + } else { povl = NULL; + } while (1) { WaitForSingleObject(ctx->ev_from_main, INFINITE); if (ctx->done) { + /* + * The main thread has asked us to shut down. Send back an + * event indicating that we've done so. Hereafter we must + * not touch ctx at all, because the main thread might + * have freed it. + */ SetEvent(ctx->ev_to_main); break; } - if (povl) + if (povl) { memset(povl, 0, sizeof(OVERLAPPED)); - ctx->writeret = WriteFile(ctx->h, ctx->buffer, ctx->len, - &ctx->lenwritten, povl); - if (povl && !ctx->writeret && GetLastError() == ERROR_IO_PENDING) - ctx->writeret = GetOverlappedResult(ctx->h, povl, - &ctx->lenwritten, TRUE); + 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 (!ctx->writeret) + if (!writeret) { + /* + * The write operation has suffered an error. Telling that + * to the main thread will cause it to set its 'defunct' + * flag and dispose of the handle structure at the next + * opportunity, so we must not touch ctx at all after + * this. + */ break; + } } + if (povl) + CloseHandle(oev); + return 0; } @@ -257,19 +355,52 @@ static void handle_try_output(struct handle_output *ctx) 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 { - int output; + HandleType type; union { struct handle_generic g; struct handle_input i; struct handle_output o; + struct handle_foreign f; } u; }; @@ -280,9 +411,9 @@ 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) + if ((uintptr_t)a->u.g.ev_to_main < (uintptr_t)b->u.g.ev_to_main) return -1; - else if ((unsigned)a->u.g.ev_to_main > (unsigned)b->u.g.ev_to_main) + else if ((uintptr_t)a->u.g.ev_to_main > (uintptr_t)b->u.g.ev_to_main) return +1; else return 0; @@ -293,9 +424,9 @@ 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) + if ((uintptr_t)*a < (uintptr_t)b->u.g.ev_to_main) return -1; - else if ((unsigned)*a > (unsigned)b->u.g.ev_to_main) + else if ((uintptr_t)*a > (uintptr_t)b->u.g.ev_to_main) return +1; else return 0; @@ -305,8 +436,9 @@ 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->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); @@ -322,7 +454,7 @@ struct handle *handle_input_new(HANDLE handle, handle_inputfn_t gotdata, add234(handles_by_evtomain, h); CreateThread(NULL, 0, handle_input_threadfunc, - &h->u.i, 0, NULL); + &h->u.i, 0, &in_threadid); h->u.i.busy = TRUE; return h; @@ -332,8 +464,9 @@ 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->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); @@ -343,6 +476,7 @@ struct handle *handle_output_new(HANDLE handle, handle_outputfn_t sentdata, 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; @@ -351,19 +485,60 @@ struct handle *handle_output_new(HANDLE handle, handle_outputfn_t sentdata, add234(handles_by_evtomain, h); CreateThread(NULL, 0, handle_output_threadfunc, - &h->u.i, 0, NULL); + &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->output); + 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; @@ -394,7 +569,7 @@ HANDLE *handle_get_events(int *nevents) static void handle_destroy(struct handle *h) { - if (h->output) + 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); @@ -404,17 +579,18 @@ static void handle_destroy(struct handle *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. + if (h->u.g.busy && h->type != HT_FOREIGN) { + /* + * If the handle is currently busy, we cannot immediately free + * it, because its subthread is in the middle of something. + * (Exception: foreign handles don't have a subthread.) + * + * 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. So + * we set the moribund flag, which will be noticed next time + * an operation completes. */ h->u.g.moribund = TRUE; } else if (h->u.g.defunct) { @@ -456,10 +632,12 @@ void handle_got_event(HANDLE event) 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. + * A moribund handle is one which we have either already + * signalled to die, or are waiting until its current I/O op + * completes to do so. Either way, it's treated as already + * dead from the external user's point of view, so we ignore + * the actual I/O result. We just signal the thread to die if + * we haven't yet done so, or destroy the handle if not. */ if (h->u.g.done) { handle_destroy(h); @@ -471,9 +649,10 @@ void handle_got_event(HANDLE event) return; } - if (!h->output) { + switch (h->type) { int backlog; + case HT_INPUT: h->u.i.busy = FALSE; /* @@ -483,13 +662,15 @@ void handle_got_event(HANDLE event) /* * EOF, or (nearly equivalently) read error. */ - h->u.i.gotdata(h, NULL, (h->u.i.readret ? 0 : -1)); h->u.i.defunct = TRUE; + h->u.i.gotdata(h, NULL, -h->u.i.readerr); } else { backlog = h->u.i.gotdata(h, h->u.i.buffer, h->u.i.len); handle_throttle(&h->u.i, backlog); } - } else { + break; + + case HT_OUTPUT: h->u.o.busy = FALSE; /* @@ -497,31 +678,37 @@ void handle_got_event(HANDLE event) * write. Call the callback to indicate that the output * buffer size has decreased, or to indicate an error. */ - if (!h->u.o.writeret) { + 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, -1); h->u.o.defunct = TRUE; + h->u.o.sentdata(h, -h->u.o.writeerr); } 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->output); + assert(h->type == HT_INPUT); handle_throttle(&h->u.i, backlog); } int handle_backlog(struct handle *h) { - assert(h->output); + assert(h->type == HT_OUTPUT); return bufchain_size(&h->u.o.queued_data); }