inject_accept.stp

# stap -g inject_accept.stp $pid
%{
#include <net/sock.h>
%}

function set_sock_keepalive:long(fd) %{
  int err = -1;
  int keepalive = 1;
  struct socket *sock = sockfd_lookup(STAP_ARG_fd, &err);
  if (sock != NULL) {
    mm_segment_t oldfs;
    oldfs = get_fs();
    set_fs(KERNEL_DS);
    err = sock_setsockopt(sock, SOL_SOCKET,
            SO_KEEPALIVE, (char __user*)&keepalive, sizeof(keepalive));
    set_fs(oldfs);
    sockfd_put(sock);
  }
  STAP_RETURN(err);
%}

probe begin {
  printf("inject begin... \n")
}

probe syscall.accept.return, syscall.accept4.return {
  # 当进程号为脚本后第一个参数时，注入keepalive
  fd = $return
  if ((pid() == $1) && (fd != -1)) {
    ok = set_sock_keepalive(fd)
    if (ok)
      printf("set_sock_keepalive %d\n", ok)
  }
}

probe end {
  printf("inject end... \n")
}