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