reexec_to_match_kernel.3

   1 .Dd Apr 14, 2008
   2 .Dt REEXEC_TO_MATCH_KERNEL 3
   3 .Os "Mac OS X"
   4 .Sh NAME
   5 .Nm reexec_to_match_kernel
   6 .Nd Re-exec the current binary to match the ABI of the running kernel
   7 .Sh LIBRARY
   8 .Lb libutil
   9 .Sh SYNOPSIS
  10 .In libutil.h
  11 .Ft int
  12 .Fo reexec_to_match_kernel
  13 .Fa "void"
  14 .Fc
  15 .Ft int
  16 .Fo reexec_to_match_lp64ness
  17 .Fa "bool isLP64"
  18 .Fc
  19 .Sh DESCRIPTION
  20 The
  21 .Fn reexec_to_match_kernel
  22 function re-executes the current binary to match the ABI of the running kernel.
  23 That is, if the current kernel is a 64-bit Intel kernel, it will attempt to
  24 execute the 64-bit x86_64 userspace slice of the universal binary. The API
  25 intentionally does not take arguments because its use should be transparent
  26 to the program and to the user.
  27 .Pp
  28 The
  29 .Fn reexec_to_match_lp64ness
  30 is coarser-grained, and only attempts to match the word width that is requested.
  31 For example, if the current system defaults to executing the 64-bit x86_64
  32 userspace slice, but the program should instead run in 32-bit i386 mode,
  33 this routine can be used.
  34 .Pp
  35 Both
  36 .Fn reexec_to_match_kernel
  37 and
  38 .Fn reexec_to_match_lp64ness
  39 can each be used exactly once in a program's lifetime. In certain circumstances,
  40 it may even be desirable to use one, and then the other.
  41 .Sh RETURN VALUES
  42 The
  43 .Fn reexec_to_match_kernel
  44 and
  45 .Fn reexec_to_match_lp64ness
  46 functions return 0 if re-execution was not required. It returns -1 and
  47 sets errno if there was an error performing the re-execution, for example
  48 if the binary is not universal, or does not contain a slice to match the running
  49 kernel's ABI. If the function succeeds, control never returns to the caller
  50 and the program starts from main() again.