lockf64.c 2.6 KB

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  1. /* Copyright (C) 1994, 1996, 1997, 1998, 2000 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. The GNU C Library is free software; you can redistribute it and/or
  4. modify it under the terms of the GNU Library General Public License as
  5. published by the Free Software Foundation; either version 2 of the
  6. License, or (at your option) any later version.
  7. The GNU C Library is distributed in the hope that it will be useful,
  8. but WITHOUT ANY WARRANTY; without even the implied warranty of
  9. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  10. Library General Public License for more details.
  11. You should have received a copy of the GNU Library General Public
  12. License along with the GNU C Library; see the file COPYING.LIB. If not,
  13. write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  14. Boston, MA 02111-1307, USA. */
  15. #include <features.h>
  16. #ifdef __UCLIBC_HAS_LFS__
  17. #if defined _FILE_OFFSET_BITS && _FILE_OFFSET_BITS != 64
  18. #undef _FILE_OFFSET_BITS
  19. #define _FILE_OFFSET_BITS 64
  20. #endif
  21. #ifndef __USE_FILE_OFFSET64
  22. # define __USE_FILE_OFFSET64 1
  23. #endif
  24. #ifndef __USE_LARGEFILE64
  25. # define __USE_LARGEFILE64 1
  26. #endif
  27. #endif
  28. #define __USE_GNU
  29. #include <sys/types.h>
  30. #include <unistd.h>
  31. #include <fcntl.h>
  32. #include <errno.h>
  33. #include <string.h>
  34. #include <sys/syscall.h>
  35. #ifdef __NR_fcntl64
  36. extern int fcntl64 (int fd, int cmd, ...);
  37. #define flock flock64
  38. #define fcntl fcntl64
  39. #define F_GETLK F_GETLK64
  40. #define F_SETLK F_SETLK64
  41. #endif
  42. /* lockf is a simplified interface to fcntl's locking facilities. */
  43. int lockf64 (int fd, int cmd, off64_t len64)
  44. {
  45. struct flock fl;
  46. off_t len = (off_t) len64;
  47. if (len64 != (off64_t) len)
  48. {
  49. /* We can't represent the length. */
  50. __set_errno(EOVERFLOW);
  51. return -1;
  52. }
  53. __memset((char *) &fl, '\0', sizeof (fl));
  54. /* lockf is always relative to the current file position. */
  55. fl.l_whence = SEEK_CUR;
  56. fl.l_start = 0;
  57. fl.l_len = len;
  58. switch (cmd)
  59. {
  60. case F_TEST:
  61. /* Test the lock: return 0 if FD is unlocked or locked by this process;
  62. return -1, set errno to EACCES, if another process holds the lock. */
  63. fl.l_type = F_RDLCK;
  64. if (fcntl (fd, F_GETLK, &fl) < 0)
  65. return -1;
  66. if (fl.l_type == F_UNLCK || fl.l_pid == __getpid ())
  67. return 0;
  68. __set_errno(EACCES);
  69. return -1;
  70. case F_ULOCK:
  71. fl.l_type = F_UNLCK;
  72. cmd = F_SETLK;
  73. break;
  74. case F_LOCK:
  75. fl.l_type = F_WRLCK;
  76. cmd = F_SETLKW;
  77. break;
  78. case F_TLOCK:
  79. fl.l_type = F_WRLCK;
  80. cmd = F_SETLK;
  81. break;
  82. default:
  83. __set_errno(EINVAL);
  84. return -1;
  85. }
  86. return fcntl(fd, cmd, &fl);
  87. }