Re: [libvirt] [PATCHv2] build: use gnulib passfd for simpler SCM_RIGHTS code

25 Apr 2011


      On 04/25/2011 01:17 AM, Laine Stump wrote:
...
...
@@ -1529,26 +1513,20 @@ virFileOpenAs(const char *path, int openflags,
mode_t mode,
          VIR_FORCE_CLOSE(pair[1]);
do {
-            ret = recvmsg(pair[0],&msg, 0);
+            ret = recvfd(pair[0], 0);
          } while (ret<  0&&  errno == EINTR);
ret == -1 and errno == EACCES on failure to transfer fd...
...
...
-        if (ret<  0) {
+        if (ret<  0&&  errno != EACCES) {
              ret = -errno;
              VIR_FORCE_CLOSE(pair[0]);
              while ((waitret = waitpid(pid, NULL, 0) == -1)
                     &&  (errno == EINTR));
              goto parenterror;
+        } else {
+            fd = ret;
          }
so now fd == -1...
...
if (!WIFEXITED(status) || (ret = -WEXITSTATUS(status)) == -EACCES ||
            fd == -1) {
            /* fall back to the simpler method, which works better in
             * some cases */
            return virFileOpenAsNoFork(path, openflags, mode, uid, gid, flags);
        }
so this uses the fallback code, regardless of child exit status, and we
also ensured that the child got reaped.
...
What if errno == EACCES? Will we be getting all the error recovery we
need in the caller?
Yes.

-- 
Eric Blake   eblake@redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org

    