LXR linux/arch/um/kernel/skas/clone.c

   1/*
   2 * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
   3 * Copyright (C) 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   4 * Licensed under the GPL
   5 */
   6
   7#include <signal.h>
   8#include <sched.h>
   9#include <asm/unistd.h>
  10#include <sys/time.h>
  11#include <as-layout.h>
  12#include <ptrace_user.h>
  13#include <stub-data.h>
  14#include <sysdep/stub.h>
  15
  16/*
  17 * This is in a separate file because it needs to be compiled with any
  18 * extraneous gcc flags (-pg, -fprofile-arcs, -ftest-coverage) disabled
  19 *
  20 * Use UM_KERN_PAGE_SIZE instead of PAGE_SIZE because that calls getpagesize
  21 * on some systems.
  22 */
  23
  24void __attribute__ ((__section__ (".__syscall_stub")))
  25stub_clone_handler(void)
  26{
  27        struct stub_data *data = (struct stub_data *) STUB_DATA;
  28        long err;
  29
  30        err = stub_syscall2(__NR_clone, CLONE_PARENT | CLONE_FILES | SIGCHLD,
  31                            STUB_DATA + UM_KERN_PAGE_SIZE / 2 - sizeof(void *));
  32        if (err != 0)
  33                goto out;
  34
  35        err = stub_syscall4(__NR_ptrace, PTRACE_TRACEME, 0, 0, 0);
  36        if (err)
  37                goto out;
  38
  39        remap_stack(data->fd, data->offset);
  40        goto done;
  41
  42 out:
  43        /*
  44         * save current result.
  45         * Parent: pid;
  46         * child: retcode of mmap already saved and it jumps around this
  47         * assignment
  48         */
  49        data->err = err;
  50 done:
  51        trap_myself();
  52}
  53