From 20a8b976130e3b2cfff5c3364169e61ec10291f3 Mon Sep 17 00:00:00 2001 From: marha Date: Fri, 19 Nov 2010 10:30:56 +0000 Subject: Copied tools directory from trunk. Here the original versions will be checked in, so that we can update them and merge the changes back in. --- tools/plink/winhandl.c | 596 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 596 insertions(+) create mode 100644 tools/plink/winhandl.c (limited to 'tools/plink/winhandl.c') 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 + +#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; +} -- cgit v1.2.3