In the wake of r7415, let's have some better error reporting.

Instead of passing -1 to its gotdata and sentdata callbacks on
error, winhandl.c will now pass the negation of the Windows error
number; and the Plink front end will now format that into an error
message and pass it on to the user.

git-svn-id: svn://svn.tartarus.org/sgt/putty@7416 cda61777-01e9-0310-a592-d414129be87e

diff --git a/windows/winhandl.c b/windows/winhandl.c
index 9f120dc..f300962 100644 (file)
--- a/windows/winhandl.c
+++ b/windows/winhandl.c
@@ -96,7 +96,7 @@ 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
@@ -113,7 +113,7 @@ static DWORD WINAPI handle_input_threadfunc(void *param)
     struct handle_input *ctx = (struct handle_input *) param;
     OVERLAPPED ovl, *povl;
     HANDLE oev;
-    int readlen;
+    int readret, readlen;
 
     if (ctx->flags & HANDLE_FLAG_OVERLAPPED) {
        povl = &ovl;
@@ -132,16 +132,21 @@ static DWORD WINAPI handle_input_threadfunc(void *param)
            memset(povl, 0, sizeof(OVERLAPPED));
            povl->hEvent = oev;
        }
-       ctx->readret = ReadFile(ctx->h, ctx->buffer, readlen,
-                               &ctx->len, povl);
-       if (!ctx->readret)
-           error = GetLastError();
-       if (povl && !ctx->readret && error == ERROR_IO_PENDING) {
+       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);
-           ctx->readret = GetOverlappedResult(ctx->h, povl, &ctx->len, FALSE);
+           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
@@ -149,12 +154,12 @@ static DWORD WINAPI handle_input_threadfunc(void *param)
             * isn't a natural EOF, _nothing_ is. So if we get that
             * particular error, we pretend it's EOF.
             */
-           if (error == ERROR_BROKEN_PIPE)
-               ctx->readret = 1;
+           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;
 
@@ -239,7 +244,7 @@ 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.
@@ -257,6 +262,7 @@ static DWORD WINAPI handle_output_threadfunc(void *param)
 {
     struct handle_output *ctx = (struct handle_output *) param;
     OVERLAPPED ovl, *povl;
+    int writeret;
 
     if (ctx->flags & HANDLE_FLAG_OVERLAPPED)
        povl = &ovl;
@@ -271,14 +277,23 @@ static DWORD WINAPI handle_output_threadfunc(void *param)
        }
        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);
+       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)
            break;
     }
 
@@ -524,7 +539,7 @@ 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.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);
@@ -538,13 +553,13 @@ 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.sentdata(h, -h->u.o.writeerr);
            h->u.o.defunct = TRUE;
        } else {
            bufchain_consume(&h->u.o.queued_data, h->u.o.lenwritten);

diff --git a/windows/winplink.c b/windows/winplink.c
index 0819934..4242600 100644 (file)
--- a/windows/winplink.c
+++ b/windows/winplink.c
@@ -228,7 +228,13 @@ int stdin_gotdata(struct handle *h, void *data, int len)
        /*
         * Special case: report read error.
         */
-       fprintf(stderr, "Unable to read from standard input\n");
+       char buf[4096];
+       FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, NULL, -len, 0,
+                     buf, lenof(buf), NULL);
+       buf[lenof(buf)-1] = '\0';
+       if (buf[strlen(buf)-1] == '\n')
+           buf[strlen(buf)-1] = '\0';
+       fprintf(stderr, "Unable to read from standard input: %s\n", buf);
        cleanup_exit(0);
     }
     noise_ultralight(len);
@@ -249,8 +255,14 @@ void stdouterr_sent(struct handle *h, int new_backlog)
        /*
         * Special case: report write error.
         */
-       fprintf(stderr, "Unable to write to standard %s\n",
-               (h == stdout_handle ? "output" : "error"));
+       char buf[4096];
+       FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, NULL, -new_backlog, 0,
+                     buf, lenof(buf), NULL);
+       buf[lenof(buf)-1] = '\0';
+       if (buf[strlen(buf)-1] == '\n')
+           buf[strlen(buf)-1] = '\0';
+       fprintf(stderr, "Unable to write to standard %s: %s\n",
+               (h == stdout_handle ? "output" : "error"), buf);
        cleanup_exit(0);
     }
     if (connopen && back->connected(backhandle)) {