lkl tools: check if host calls are initialized

The host calls may not be initialized from the constructor calls if
another constructor calls one of the hooked functions. Manually check
for that to avoid this issue.

Reported-by: Hajime Tazaki <thehajime@gmail.com>
Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>

tools/lkl/lib/hijack/hijack.c

@@ -68,6 +68,8 @@ static host_call host_calls[__lkl__NR_syscalls];
  { \
  long p[6] = {p1, p2, p3, p4, p5, p6 }; \
  \
+ if (!host_calls[__lkl__NR_##name]) \
+ host_calls[__lkl__NR_##name] = resolve_sym(#name); \
  if (!is_lklfd(p1)) \
  return host_calls[__lkl__NR_##name](p1, p2, p3, \
  p4, p5, p6); \
@@ -96,6 +98,9 @@ static host_call host_calls[__lkl__NR_syscalls];
  asm(".global " #name); \
  asm(".set " #name "," #name "_hook"); \
 
+#define CHECK_HOST_CALL(name) \
+ if (!host_##name) \
+ host_##name = resolve_sym(#name)
 
 static int lkl_call(int nr, int args, ...)
 {
@@ -136,6 +141,7 @@ HOST_CALL(setsockopt);
 int setsockopt(int fd, int level, int optname, const void *optval,
  socklen_t optlen)
 {
+ CHECK_HOST_CALL(setsockopt);
  if (!is_lklfd(fd))
  return host_setsockopt(fd, level, optname, optval, optlen);
  return lkl_call(__lkl__NR_setsockopt, 5, fd, lkl_solevel_xlate(level),
@@ -145,6 +151,7 @@ int setsockopt(int fd, int level, int optname, const void *optval,
 HOST_CALL(getsockopt);
 int getsockopt(int fd, int level, int optname, void *optval, socklen_t *optlen)
 {
+ CHECK_HOST_CALL(getsockopt);
  if (!is_lklfd(fd))
  return host_setsockopt(fd, level, optname, optval, optlen);
  return lkl_call(__lkl__NR_getsockopt, 5, fd, lkl_solevel_xlate(level),
@@ -154,6 +161,7 @@ int getsockopt(int fd, int level, int optname, void *optval, socklen_t *optlen)
 HOST_CALL(socket);
 int socket(int domain, int type, int protocol)
 {
+ CHECK_HOST_CALL(socket);
  if (domain == AF_UNIX)
  return host_socket(domain, type, protocol);
 
@@ -170,6 +178,8 @@ int ioctl(int fd, unsigned long req, ...)
  arg = va_arg(vl, long);
  va_end(vl);
 
+ CHECK_HOST_CALL(ioctl);
+
  if (!is_lklfd(fd))
  return host_ioctl(fd, req, arg);
  return lkl_call(__lkl__NR_fcntl, 3, fd, lkl_ioctl_req_xlate(req), arg);
@@ -186,6 +196,8 @@ int fcntl(int fd, int cmd, ...)
  arg = va_arg(vl, long);
  va_end(vl);
 
+ CHECK_HOST_CALL(fcntl);
+
  if (!is_lklfd(fd))
  return host_fcntl(fd, cmd, arg);
  return lkl_call(__lkl__NR_fcntl, 3, fd, lkl_fcntl_cmd_xlate(cmd), arg);
@@ -196,6 +208,8 @@ int poll(struct pollfd *fds, nfds_t nfds, int timeout)
 {
  unsigned int i, lklfds = 0, hostfds = 0;
 
+ CHECK_HOST_CALL(poll);
+
  for (i = 0; i < nfds; i++) {
  if (is_lklfd(fds[i].fd))
  lklfds = 1;
@@ -221,6 +235,8 @@ int select(int nfds, fd_set *r, fd_set *w, fd_set *e, struct timeval *t)
 {
  int fd, hostfds = 0, lklfds = 0;
 
+ CHECK_HOST_CALL(select);
+
  for (fd = 0; fd < nfds; fd++) {
  if (r != 0 && FD_ISSET(fd, r)) {
  if (is_lklfd(fd))
@@ -257,10 +273,11 @@ HOOK_CALL(epoll_create)
 HOST_CALL(epoll_ctl);
 int epoll_ctl(int epollfd, int op, int fd, struct epoll_event *event)
 {
+ CHECK_HOST_CALL(epoll_ctl);
+
  if (is_lklfd(epollfd) != is_lklfd(fd))
  return lkl_set_errno(LKL_EOPNOTSUPP);
 
-
  if (!is_lklfd(epollfd))
  return host_epoll_ctl(epollfd, op, fd, event);