Re: [Libguestfs] [PATCH v3 libguestfs] launch: Implement a safer getumask.

On 04/14/2016 07:57 AM, Richard W.M. Jones wrote: > On Thu, Apr 14, 2016 at 07:38:23AM -0600, Eric Blake wrote: >>> + /* Read the umask. */ >>> + if (read (fd[0], &mask, sizeof mask) != sizeof mask) { >>> + perrorf (g, "read"); >>> + close (fd[0]); >>> + return -1; >> >> Oops - this strands a child process. You have to reap the child, even >> if the read() failed. > > Bleah that was stupid. Try attached version - the only difference is > I added a waitpid call to the error path above. But without looping on EINTR...

+ + /* Read the umask. */ + if (read (fd[0], &mask, sizeof mask) != sizeof mask) { + perrorf (g, "read"); + close (fd[0]); + waitpid (pid, NULL, 0); I think it's enough to make this line: while (waitpid (pid, &status, 0) == -1 && errno == EINTR); + return -1; as you've already reported the initial error, and are merely focused on cleanup of the child. + } + close (fd[0]); + + again: + if (waitpid (pid, &status, 0) == -1) { + if (errno == EINTR) goto again; + perrorf (g, "waitpid"); + return -1; Anything else, like trying to reuse the again: loop, seems like it be more complicated control flow. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org