arch/um/kernel/skas/clone.c

   1 /*
   2  * Copyright (C) 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <signal.h>
   7 #include <sched.h>
   8 #include <asm/unistd.h>
   9 #include <sys/time.h>
  10 #include <as-layout.h>
  11 #include <ptrace_user.h>
  12 #include <stub-data.h>
  13 #include <sysdep/stub.h>
  14
  15 /*
  16  * This is in a separate file because it needs to be compiled with any
  17  * extraneous gcc flags (-pg, -fprofile-arcs, -ftest-coverage) disabled
  18  *
  19  * Use UM_KERN_PAGE_SIZE instead of PAGE_SIZE because that calls getpagesize
  20  * on some systems.
  21  */
  22
  23 void __attribute__ ((__section__ (".__syscall_stub")))
  24 stub_clone_handler(void)
  25 {
  26         struct stub_data *data = (struct stub_data *) STUB_DATA;
  27         long err;
  28
  29         err = stub_syscall2(__NR_clone, CLONE_PARENT | CLONE_FILES | SIGCHLD,
  30                             STUB_DATA + UM_KERN_PAGE_SIZE / 2 - sizeof(void *));
  31         if (err != 0)
  32                 goto out;
  33
  34         err = stub_syscall4(__NR_ptrace, PTRACE_TRACEME, 0, 0, 0);
  35         if (err)
  36                 goto out;
  37
  38         err = stub_syscall3(__NR_setitimer, ITIMER_VIRTUAL,
  39                             (long) &data->timer, 0);
  40         if (err)
  41                 goto out;
  42
  43         remap_stack(data->fd, data->offset);
  44         goto done;
  45
  46  out:
  47         /*
  48          * save current result.
  49          * Parent: pid;
  50          * child: retcode of mmap already saved and it jumps around this
  51          * assignment
  52          */
  53         data->err = err;
  54  done:
  55         trap_myself();
  56 }