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
  13 /* This is in a separate file because it needs to be compiled with any
  14  * extraneous gcc flags (-pg, -fprofile-arcs, -ftest-coverage) disabled
  15  */
  16 void __attribute__ ((__section__ (".__syscall_stub")))
  17 stub_clone_handler(void)
  18 {
  19         long err;
  20         struct stub_data *from = (struct stub_data *) UML_CONFIG_STUB_DATA;
  21
  22         err = stub_syscall2(__NR_clone, CLONE_PARENT | CLONE_FILES | SIGCHLD,
  23                             UML_CONFIG_STUB_DATA + PAGE_SIZE / 2 -
  24                             sizeof(void *));
  25         if(err != 0)
  26                 goto out;
  27
  28         err = stub_syscall4(__NR_ptrace, PTRACE_TRACEME, 0, 0, 0);
  29         if(err)
  30                 goto out;
  31
  32         err = stub_syscall3(__NR_setitimer, ITIMER_VIRTUAL,
  33                             (long) &from->timer, 0);
  34         if(err)
  35                 goto out;
  36
  37         err = stub_syscall6(STUB_MMAP_NR, UML_CONFIG_STUB_DATA, PAGE_SIZE,
  38                             PROT_READ | PROT_WRITE, MAP_FIXED | MAP_SHARED,
  39                             from->fd, from->offset);
  40  out:
  41         /* save current result. Parent: pid; child: retcode of mmap */
  42         from->err = err;
  43         trap_myself();
  44 }