On Thu, Oct 30, 2008 at 02:06:20PM -0400, Cole Robinson wrote: > The attached patch logs the the argv's passed to > the virExec and virRun functions. There's a bit of > trickery here: since virRun is just a wrapper for > virExec, we don't want the argv string to be logged > twice. > > I addressed this by renaming virExec to __virExec, > and keeping the original function name to simply > debug the argv and then hand off control. This > means anytime virExec is explictly called, the > argv will be logged, but if functions wish to by > pass that they can just call __virExec (which is > what virRun does.) > I'm a little confused about why we can't just put the logging calling directly in the existing virExec() function. Since the first thing virRun() does is to call virExec() this would seem to be sufficient without need of a wrapper. Daniel

The attached patch is my second cut at reading stdout and stderr of the command virRun kicks off. There is no hard limit to the amount of data we read now, and we use a poll loop to avoid any possible full buffer issues. If stdout or stderr had any content, we DEBUG it, and if the command appears to fail we return stderr in the error message. So now, trying to stop a logical pool with active volumes will return: $ sudo virsh pool-destroy vgdata libvir: error : internal error '/sbin/vgchange -an vgdata' exited with non-zero status 5 and signal 0: Can't deactivate volume group "vgdata" with 2 open logical volume(s) error: Failed to destroy pool vgdata

+ fds[0].fd = outfd; + fds[0].events = POLLIN; + finished[0] = 0; + fds[1].fd = errfd; + fds[1].events = POLLIN; + finished[1] = 0; + + while(!(finished[0] && finished[1])) { + + if (poll(fds, ARRAY_CARDINALITY(fds), -1) < 0) { + if (errno == EAGAIN) + continue; + goto pollerr; + } + + for (i = 0; i < ARRAY_CARDINALITY(fds); ++i) { + char data[1024], **buf; + int got, size; + + if (!(fds[i].revents)) + continue; + else if (fds[i].revents & POLLHUP) + finished[i] = 1; + + if (!(fds[i].revents & POLLIN)) { + if (fds[i].revents & POLLHUP) + continue; + + ReportError(conn, VIR_ERR_INTERNAL_ERROR, + "%s", _("Unknown poll response.")); + goto error; + } + + got = read(fds[i].fd, data, sizeof(data)); + + if (got == 0) { + finished[i] = 1; + continue; + } + if (got < 0) { + if (errno == EINTR) + continue; + if (errno == EAGAIN) + break; + goto pollerr; + } - while ((ret = waitpid(childpid, &exitstatus, 0) == -1) && errno == EINTR); - if (ret == -1) { + buf = ((fds[i].fd == outfd) ? &outbuf : &errbuf); + size = (*buf ? strlen(*buf) : 0); + if (VIR_REALLOC_N(*buf, size+got+1) < 0) { + ReportError(conn, VIR_ERR_NO_MEMORY, "%s", "realloc buf"); + goto error; + } + memmove(*buf+size, data, got); + (*buf)[size+got] = '\0'; + } + continue; + + pollerr: + ReportError(conn, VIR_ERR_INTERNAL_ERROR, + _("poll error: %s"), strerror(errno)); + goto error; + }

Daniel P. Berrange wrote: > On Thu, Oct 30, 2008 at 02:06:35PM -0400, Cole Robinson wrote: > >> The attached patch is my second cut at reading >> stdout and stderr of the command virRun kicks >> off. There is no hard limit to the amount of >> data we read now, and we use a poll loop to >> avoid any possible full buffer issues. >> >> If stdout or stderr had any content, we DEBUG >> it, and if the command appears to fail we >> return stderr in the error message. So now, >> trying to stop a logical pool with active >> volumes will return: >> >> $ sudo virsh pool-destroy vgdata >> libvir: error : internal error '/sbin/vgchange -an vgdata' exited with non-zero status 5 and signal 0: Can't deactivate volume group "vgdata" with 2 open logical volume(s) >> error: Failed to destroy pool vgdata >> <snip> > I think it'd be nice to move the I/O processing loop out of the > virRun() function and into a separate helper functiion along the > lines of > > virPipeReadUntilEOF(int outfd, int errfd, char **outbuf, char **errbuf) > > Daniel > Okay, updated patch attached. Also addresses the point Jim raised about poll.h