truncate64.c 1.5 KB

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  1. /*
  2. * truncate64 syscall. Copes with 64 bit and 32 bit machines
  3. * and on 32 bit machines this sends things into the kernel as
  4. * two 32-bit arguments (high and low 32 bits of length) that
  5. * are ordered based on endianess. It turns out endian.h has
  6. * just the macro we need to order things, __LONG_LONG_PAIR.
  7. *
  8. * Copyright (C) 2002 Erik Andersen <andersen@codepoet.org>
  9. *
  10. * This file is subject to the terms and conditions of the GNU
  11. * Lesser General Public License. See the file COPYING.LIB in
  12. * the main directory of this archive for more details.
  13. */
  14. #include <features.h>
  15. #include <unistd.h>
  16. #include <errno.h>
  17. #include <endian.h>
  18. #include <stdint.h>
  19. #include <sys/syscall.h>
  20. #if defined __UCLIBC_HAS_LFS__ && defined __NR_truncate64
  21. #ifndef INLINE_SYSCALL
  22. #define INLINE_SYSCALL(name, nr, args...) __syscall_truncate64 (args)
  23. #define __NR___syscall_truncate64 __NR_truncate64
  24. static inline _syscall3(int, __syscall_truncate64, const char *, path, int, high_length, int, low_length);
  25. #endif
  26. #if __WORDSIZE == 64
  27. /* For a 64 bit machine, life is simple... */
  28. _syscall2(int, truncate64, const char *, path, __off64_t, length);
  29. #elif __WORDSIZE == 32
  30. /* The exported truncate64 function. */
  31. int truncate64 (const char * path, __off64_t length)
  32. {
  33. uint32_t low = length & 0xffffffff;
  34. uint32_t high = length >> 32;
  35. return INLINE_SYSCALL(truncate64, 3, path, __LONG_LONG_PAIR (high, low));
  36. }
  37. #else
  38. #error Your machine is not 64 bit or 32 bit, I am dazed and confused.
  39. #endif
  40. #endif /* __UCLIBC_HAS_LFS__ */