[libvirt] [PATCH 9/9] fdstream: don't raise error on SIGPIPE if abort requested

[Cole Robinson]

The iohelper dies on SIGPIPE if the stream is closed before all data
is processed. IMO this should be an error condition for virStreamFinish
according to docs like:

  * This method is a synchronization point for all asynchronous
  * errors, so if this returns a success code the application can
  * be sure that all data has been successfully processed.

However for virStreamAbort, not so much:

  * Request that the in progress data transfer be cancelled
  * abnormally before the end of the stream has been reached.
  * For output streams this can be used to inform the driver
  * that the stream is being terminated early. For input
  * streams this can be used to inform the driver that it
  * should stop sending data.

Without this, virStreamAbort will realistically always error for
active streams like domain console. So, treat the SIGPIPE case
as non-fatal if abort is requested.

Note, this will only affect an explicit user requested abort. An
abnormal abort, like from a server error, always raises an error
in the daemon.
---
 src/fdstream.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/fdstream.c b/src/fdstream.c
index 155311a..f22107c 100644
--- a/src/fdstream.c
+++ b/src/fdstream.c
@@ -242,7 +242,7 @@ virFDStreamAddCallback(virStreamPtr st,
 }
 
 static int
-virFDStreamCloseCommand(struct virFDStreamData *fdst)
+virFDStreamCloseCommand(struct virFDStreamData *fdst, bool streamAbort)
 {
     char buf[1024];
     ssize_t len;
@@ -265,6 +265,12 @@ virFDStreamCloseCommand(struct virFDStreamData *fdst)
         if (buf[0] != '\0') {
             virReportError(VIR_ERR_INTERNAL_ERROR, "%s", buf);
         } else if (WIFSIGNALED(status) && WTERMSIG(status) == SIGPIPE) {
+            if (streamAbort) {
+                /* Explicit abort request means the caller doesn't care
+                   if there's data left over, so skip the error */
+                goto out;
+            }
+
             virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                            _("I/O helper exited "
                              "before all data was processed"));
@@ -278,6 +284,7 @@ virFDStreamCloseCommand(struct virFDStreamData *fdst)
         goto error;
     }
 
+ out:
     ret = 0;
  error:
     virCommandFree(fdst->cmd);
@@ -329,7 +336,7 @@ virFDStreamCloseInt(virStreamPtr st, bool streamAbort)
 
     /* mutex locked */
     ret = VIR_CLOSE(fdst->fd);
-    if (virFDStreamCloseCommand(fdst) < 0)
+    if (virFDStreamCloseCommand(fdst, streamAbort) < 0)
         ret = -1;
 
     if (VIR_CLOSE(fdst->errfd) < 0)
-- 
2.7.3