Function dmtcp_spawn

src/posix_spawn.cpp:38–158

Spawn a new process executing PATH with the attributes describes in *ATTRP. Before running the process perform the actions described in FILE-ACTIONS. */

/* Spawn a new process executing PATH with the attributes describes in *ATTRP.
   Before running the process perform the actions described in FILE-ACTIONS. */
int
dmtcp_spawn(pid_t *pid,
            const char *file,
            const posix_spawn_file_actions_t *file_actions,
            const posix_spawnattr_t *attrp,
            char *const argv[],
            char *const envp[])
{
  /* Do this once.  */
  short int flags = attrp == NULL ? 0 : attrp->__flags;

  // TODO(kapil): Add support for POSIX_SPAWN_USEVFORK.
  pid_t new_pid = fork();

  // Parent.
  if (new_pid != 0) {
    if (new_pid < 0) {
      return errno;
    }

    /* The call was successful.  Store the PID if necessary.  */
    if (pid != NULL) {
      *pid = new_pid;
    }

    return 0;
  }

  /* Set signal mask.  */
  if ((flags & POSIX_SPAWN_SETSIGMASK) != 0 &&
      sigprocmask(SIG_SETMASK, &attrp->__ss, NULL) != 0) {
    exit(SPAWN_ERROR);
  }

  /* Set signal default action.  */
  if ((flags & POSIX_SPAWN_SETSIGDEF) != 0) {
    struct sigaction sa = {};
    sa.sa_handler = SIG_DFL;

    int ckptSig = dmtcp_get_ckpt_signal();
    for (int sig = 1; sig < _NSIG; ++sig) {
      if (sig != ckptSig && sigismember(&attrp->__sd, sig) != 0 &&
          sigaction(sig, &sa, NULL) != 0) {
        JTRACE("sigaction failed");
        exit(SPAWN_ERROR);
      }
    }
  }

  /* Set the process group ID.  */
  if ((flags & POSIX_SPAWN_SETPGROUP) != 0 && setpgid(0, attrp->__pgrp) != 0) {
    JTRACE("setpgid failed");
    exit(SPAWN_ERROR);
  }

  /* Set the effective user and group IDs.  */
  if ((flags & POSIX_SPAWN_RESETIDS) != 0 &&
      (seteuid(getuid()) != 0 || setegid(getgid()) != 0)) {