int libxl__datacopier_start(libxl__datacopier_state *dc)
{
int rc;
STATE_AO_GC(dc->ao);
libxl__datacopier_init(dc);
assert(dc->readfd >= 0 || dc->writefd >= 0);
assert(!(dc->readbuf && dc->bytes_to_read == -1));
dc->abrt.ao = ao;
dc->abrt.callback = datacopier_abort;
rc = libxl__ao_abortable_register(&dc->abrt);
if (rc) goto out;
if (dc->readfd >= 0) {
rc = libxl__ev_fd_register(gc, &dc->toread, datacopier_readable,
dc->readfd, POLLIN);
if (rc) goto out;
}
if (dc->writefd >= 0) {
rc = libxl__ev_fd_register(gc, &dc->towrite, datacopier_writable,
dc->writefd, POLLOUT);
if (rc) goto out;
}
return 0;
out:
libxl__datacopier_kill(dc);
return rc;
}
static void datacopier_check_state(libxl__egc *egc, libxl__datacopier_state *dc)
{
STATE_AO_GC(dc->ao);
int rc;
if (dc->used && !dc->readbuf) {
if (!libxl__ev_fd_isregistered(&dc->towrite)) {
rc = libxl__ev_fd_register(gc, &dc->towrite, datacopier_writable,
dc->writefd, POLLOUT);
if (rc) {
LOG(ERROR, "unable to establish write event on %s"
" during copy of %s", dc->writewhat, dc->copywhat);
datacopier_callback(egc, dc, ERROR_FAIL, -1, EIO);
return;
}
}
} else if (!libxl__ev_fd_isregistered(&dc->toread) ||
dc->bytes_to_read == 0) {
/* we have had eof */
datacopier_callback(egc, dc, 0, 0, 0);
return;
} else {
/* nothing buffered, but still reading */
libxl__ev_fd_deregister(gc, &dc->towrite);
}
}
int libxl__datacopier_start(libxl__datacopier_state *dc)
{
int rc;
STATE_AO_GC(dc->ao);
libxl__datacopier_init(dc);
rc = libxl__ev_fd_register(gc, &dc->toread, datacopier_readable,
dc->readfd, POLLIN);
if (rc) goto out;
rc = libxl__ev_fd_register(gc, &dc->towrite, datacopier_writable,
dc->writefd, POLLOUT);
if (rc) goto out;
return 0;
out:
libxl__datacopier_kill(dc);
return rc;
}
static void run_helper(libxl__egc *egc, libxl__save_helper_state *shs,
const char *mode_arg, int stream_fd,
const int *preserve_fds, int num_preserve_fds,
const unsigned long *argnums, int num_argnums)
{
STATE_AO_GC(shs->ao);
const char *args[4 + num_argnums];
const char **arg = args;
int i, rc;
/* Resources we must free */
libxl__carefd *childs_pipes[2] = { 0,0 };
/* Convenience aliases */
const uint32_t domid = shs->domid;
shs->rc = 0;
shs->completed = 0;
shs->pipes[0] = shs->pipes[1] = 0;
libxl__ev_fd_init(&shs->readable);
libxl__ev_child_init(&shs->child);
shs->stdin_what = GCSPRINTF("domain %"PRIu32" save/restore helper"
" stdin pipe", domid);
shs->stdout_what = GCSPRINTF("domain %"PRIu32" save/restore helper"
" stdout pipe", domid);
*arg++ = getenv("LIBXL_SAVE_HELPER") ?: PRIVATE_BINDIR "/" "libxl-save-helper";
*arg++ = mode_arg;
const char **stream_fd_arg = arg++;
for (i=0; i<num_argnums; i++)
*arg++ = GCSPRINTF("%lu", argnums[i]);
*arg++ = 0;
assert(arg == args + ARRAY_SIZE(args));
libxl__carefd_begin();
int childfd;
for (childfd=0; childfd<2; childfd++) {
/* Setting up the pipe for the child's fd childfd */
int fds[2];
if (libxl_pipe(CTX,fds)) {
rc = ERROR_FAIL;
libxl__carefd_unlock();
goto out;
}
int childs_end = childfd==0 ? 0 /*read*/ : 1 /*write*/;
int our_end = childfd==0 ? 1 /*write*/ : 0 /*read*/;
childs_pipes[childfd] = libxl__carefd_record(CTX, fds[childs_end]);
shs->pipes[childfd] = libxl__carefd_record(CTX, fds[our_end]);
}
libxl__carefd_unlock();
pid_t pid = libxl__ev_child_fork(gc, &shs->child, helper_exited);
if (!pid) {
if (stream_fd <= 2) {
stream_fd = dup(stream_fd);
if (stream_fd < 0) {
LOGE(ERROR,"dup migration stream fd");
exit(-1);
}
}
libxl_fd_set_cloexec(CTX, stream_fd, 0);
*stream_fd_arg = GCSPRINTF("%d", stream_fd);
for (i=0; i<num_preserve_fds; i++)
if (preserve_fds[i] >= 0) {
assert(preserve_fds[i] > 2);
libxl_fd_set_cloexec(CTX, preserve_fds[i], 0);
}
libxl__exec(gc,
libxl__carefd_fd(childs_pipes[0]),
libxl__carefd_fd(childs_pipes[1]),
-1,
args[0], (char**)args, 0);
}
libxl__carefd_close(childs_pipes[0]);
libxl__carefd_close(childs_pipes[1]);
rc = libxl__ev_fd_register(gc, &shs->readable, helper_stdout_readable,
libxl__carefd_fd(shs->pipes[1]), POLLIN|POLLPRI);
if (rc) goto out;
return;
out:
libxl__carefd_close(childs_pipes[0]);
libxl__carefd_close(childs_pipes[1]);
helper_failed(egc, shs, rc);;
}