sysdeps/unix/sysdep.h

   1 /* Copyright (C) 1991-2015 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <sysdeps/generic/sysdep.h>
  19
  20 #include <sys/syscall.h>
  21 #define HAVE_SYSCALLS
  22
  23 /* Note that using a `PASTE' macro loses.  */
  24 #define SYSCALL__(name, args)   PSEUDO (__##name, name, args)
  25 #define SYSCALL(name, args)     PSEUDO (name, name, args)
  26
  27 /* Cancellation macros.  */
  28 #define __SYSCALL_NARGS_X(a,b,c,d,e,f,g,n,...) n
  29 #define __SYSCALL_NARGS(...) \
  30   __SYSCALL_NARGS_X (__VA_ARGS__, 7, 6, 5, 4, 3, 2, 1, 0,)
  31
  32 #define SYSCALL_CANCEL(name, ...) \
  33   ({                                                                         \
  34     long int sc_ret;                                                         \
  35     if (SINGLE_THREAD_P)                                                     \
  36       sc_ret = INLINE_SYSCALL (name, __SYSCALL_NARGS(__VA_ARGS__),           \
  37                                __VA_ARGS__);                                 \
  38     else                                                                     \
  39       {                                                                      \
  40         int sc_cancel_oldtype = LIBC_CANCEL_ASYNC ();                        \
  41         sc_ret = INLINE_SYSCALL (name, __SYSCALL_NARGS (__VA_ARGS__),        \
  42                                  __VA_ARGS__);                               \
  43         LIBC_CANCEL_RESET (sc_cancel_oldtype);                               \
  44       }                                                                      \
  45     sc_ret;                                                                  \
  46   })
  47
  48 /* Machine-dependent sysdep.h files are expected to define the macro
  49    PSEUDO (function_name, syscall_name) to emit assembly code to define the
  50    C-callable function FUNCTION_NAME to do system call SYSCALL_NAME.
  51    r0 and r1 are the system call outputs.  MOVE(x, y) should be defined as
  52    an instruction such that "MOVE(r1, r0)" works.  ret should be defined
  53    as the return instruction.  */
  54
  55 #ifndef SYS_ify
  56 #define SYS_ify(syscall_name) SYS_##syscall_name
  57 #endif
  58
  59 /* Terminate a system call named SYM.  This is used on some platforms
  60    to generate correct debugging information.  */
  61 #ifndef PSEUDO_END
  62 #define PSEUDO_END(sym)
  63 #endif
  64 #ifndef PSEUDO_END_NOERRNO
  65 #define PSEUDO_END_NOERRNO(sym) PSEUDO_END(sym)
  66 #endif
  67 #ifndef PSEUDO_END_ERRVAL
  68 #define PSEUDO_END_ERRVAL(sym)  PSEUDO_END(sym)
  69 #endif
  70
  71 /* Wrappers around system calls should normally inline the system call code.
  72    But sometimes it is not possible or implemented and we use this code.  */
  73 #ifndef INLINE_SYSCALL
  74 #define INLINE_SYSCALL(name, nr, args...) __syscall_##name (args)
  75 #endif