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