Revamp of EOF handling in all network connections, pipes and other

[u/mdw/putty] / unix / uxplink.c

diff --git a/unix/uxplink.c b/unix/uxplink.c
index 4d36e50..aeb37f6 100644 (file)
--- a/unix/uxplink.c
+++ b/unix/uxplink.c
@@ -383,6 +383,7 @@ void cleanup_termios(void)
 }
 
 bufchain stdout_data, stderr_data;
+enum { EOF_NO, EOF_PENDING, EOF_SENT } outgoingeof;
 
 int try_output(int is_stderr)
 {
@@ -391,23 +392,26 @@ int try_output(int is_stderr)
     void *senddata;
     int sendlen, ret, fl;
 
-    if (bufchain_size(chain) == 0)
-        return bufchain_size(&stdout_data) + bufchain_size(&stderr_data);
-
-    fl = fcntl(fd, F_GETFL);
-    if (fl != -1 && !(fl & O_NONBLOCK))
-       fcntl(fd, F_SETFL, fl | O_NONBLOCK);
-    do {
-       bufchain_prefix(chain, &senddata, &sendlen);
-       ret = write(fd, senddata, sendlen);
-       if (ret > 0)
-           bufchain_consume(chain, ret);
-    } while (ret == sendlen && bufchain_size(chain) != 0);
-    if (fl != -1 && !(fl & O_NONBLOCK))
-       fcntl(fd, F_SETFL, fl);
-    if (ret < 0 && errno != EAGAIN) {
-       perror(is_stderr ? "stderr: write" : "stdout: write");
-       exit(1);
+    if (bufchain_size(chain) > 0) {
+        fl = fcntl(fd, F_GETFL);
+        if (fl != -1 && !(fl & O_NONBLOCK))
+            fcntl(fd, F_SETFL, fl | O_NONBLOCK);
+        do {
+            bufchain_prefix(chain, &senddata, &sendlen);
+            ret = write(fd, senddata, sendlen);
+            if (ret > 0)
+                bufchain_consume(chain, ret);
+        } while (ret == sendlen && bufchain_size(chain) != 0);
+        if (fl != -1 && !(fl & O_NONBLOCK))
+            fcntl(fd, F_SETFL, fl);
+        if (ret < 0 && errno != EAGAIN) {
+            perror(is_stderr ? "stderr: write" : "stdout: write");
+            exit(1);
+        }
+    }
+    if (outgoingeof == EOF_PENDING && bufchain_size(&stdout_data) == 0) {
+        close(STDOUT_FILENO);
+        outgoingeof = EOF_SENT;
     }
     return bufchain_size(&stdout_data) + bufchain_size(&stderr_data);
 }
@@ -419,6 +423,7 @@ int from_backend(void *frontend_handle, int is_stderr,
        bufchain_add(&stderr_data, data, len);
        return try_output(TRUE);
     } else {
+        assert(outgoingeof == EOF_NO);
        bufchain_add(&stdout_data, data, len);
        return try_output(FALSE);
     }
@@ -434,6 +439,14 @@ int from_backend_untrusted(void *frontend_handle, const char *data, int len)
     return 0; /* not reached */
 }
 
+int from_backend_eof(void *frontend_handle)
+{
+    assert(outgoingeof == EOF_NO);
+    outgoingeof = EOF_PENDING;
+    try_output(FALSE);
+    return FALSE;   /* do not respond to incoming EOF with outgoing */
+}
+
 int get_userpass_input(prompts_t *p, unsigned char *in, int inlen)
 {
     int ret;
@@ -599,6 +612,10 @@ int main(int argc, char **argv)
     default_protocol = PROT_SSH;
     default_port = 22;
 
+    bufchain_init(&stdout_data);
+    bufchain_init(&stderr_data);
+    outgoingeof = EOF_NO;
+
     flags = FLAG_STDERR | FLAG_STDERR_TTY;
 
     stderr_tty_init();