arch/um/kernel/skas/syscall.c

   1 /*
   2  * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/ptrace.h>
   8 #include <kern_util.h>
   9 #include <sysdep/ptrace.h>
  10 #include <sysdep/syscalls.h>
  11
  12 extern int syscall_table_size;
  13 #define NR_SYSCALLS (syscall_table_size / sizeof(void *))
  14
  15 void handle_syscall(struct uml_pt_regs *r)
  16 {
  17         struct pt_regs *regs = container_of(r, struct pt_regs, regs);
  18         long result;
  19         int syscall;
  20
  21         if (syscall_trace_enter(regs)) {
  22                 result = -ENOSYS;
  23                 goto out;
  24         }
  25
  26         /*
  27          * This should go in the declaration of syscall, but when I do that,
  28          * strace -f -c bash -c 'ls ; ls' breaks, sometimes not tracing
  29          * children at all, sometimes hanging when bash doesn't see the first
  30          * ls exit.
  31          * The assembly looks functionally the same to me.  This is
  32          *     gcc version 4.0.1 20050727 (Red Hat 4.0.1-5)
  33          * in case it's a compiler bug.
  34          */
  35         syscall = UPT_SYSCALL_NR(r);
  36         if ((syscall >= NR_SYSCALLS) || (syscall < 0))
  37                 result = -ENOSYS;
  38         else result = EXECUTE_SYSCALL(syscall, regs);
  39
  40 out:
  41         PT_REGS_SET_SYSCALL_RETURN(regs, result);
  42
  43         syscall_trace_leave(regs);
  44 }