arch/um/kernel/skas/clone.c

   1 #include <sched.h>
   2 #include <signal.h>
   3 #include <sys/mman.h>
   4 #include <sys/time.h>
   5 #include <asm/unistd.h>
   6 #include <asm/page.h>
   7 #include "ptrace_user.h"
   8 #include "skas.h"
   9 #include "stub-data.h"
  10 #include "uml-config.h"
  11 #include "sysdep/stub.h"
  12 #include "kern_constants.h"
  13
  14 #ifndef CLONE_PARENT
  15 # define CLONE_PARENT  0x00008000
  16 #endif
  17
  18 /* This is in a separate file because it needs to be compiled with any
  19  * extraneous gcc flags (-pg, -fprofile-arcs, -ftest-coverage) disabled
  20  *
  21  * Use UM_KERN_PAGE_SIZE instead of PAGE_SIZE because that calls getpagesize
  22  * on some systems.
  23  */
  24
  25 void __attribute__ ((__section__ (".__syscall_stub")))
  26 stub_clone_handler(void)
  27 {
  28         struct stub_data *data = (struct stub_data *) UML_CONFIG_STUB_DATA;
  29         long err;
  30
  31         err = stub_syscall2(__NR_clone, CLONE_PARENT | CLONE_FILES | SIGCHLD,
  32                             UML_CONFIG_STUB_DATA + UM_KERN_PAGE_SIZE / 2 -
  33                             sizeof(void *));
  34         if(err != 0)
  35                 goto out;
  36
  37         err = stub_syscall4(__NR_ptrace, PTRACE_TRACEME, 0, 0, 0);
  38         if(err)
  39                 goto out;
  40
  41         err = stub_syscall3(__NR_setitimer, ITIMER_VIRTUAL,
  42                             (long) &data->timer, 0);
  43         if(err)
  44                 goto out;
  45
  46         remap_stack(data->fd, data->offset);
  47         goto done;
  48
  49  out:
  50         /* save current result.
  51          * Parent: pid;
  52          * child: retcode of mmap already saved and it jumps around this
  53          * assignment
  54          */
  55         data->err = err;
  56  done:
  57         trap_myself();
  58 }