lockf64.c 2.5 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 <_lfs_64.h>
  16. #include <sys/types.h>
  17. #include <unistd.h>
  18. #include <fcntl.h>
  19. #include <errno.h>
  20. #include <string.h>
  21. #include <sys/syscall.h>
  22. #ifdef __NR_fcntl64
  23. #define flock flock64
  24. #define fcntl fcntl64
  25. #undef F_GETLK
  26. #define F_GETLK F_GETLK64
  27. #undef F_SETLK
  28. #define F_SETLK F_SETLK64
  29. /* libc_hidden_proto(fcntl64) */
  30. #else
  31. /* libc_hidden_proto(fcntl) */
  32. #endif
  33. /* Experimentally off - libc_hidden_proto(memset) */
  34. /* libc_hidden_proto(getpid) */
  35. /* lockf is a simplified interface to fcntl's locking facilities. */
  36. /* libc_hidden_proto(lockf64) */
  37. int lockf64 (int fd, int cmd, off64_t len64)
  38. {
  39. struct flock fl;
  40. off_t len = (off_t) len64;
  41. if (len64 != (off64_t) len)
  42. {
  43. /* We can't represent the length. */
  44. __set_errno(EOVERFLOW);
  45. return -1;
  46. }
  47. memset((char *) &fl, '\0', sizeof (fl));
  48. /* lockf is always relative to the current file position. */
  49. fl.l_whence = SEEK_CUR;
  50. fl.l_start = 0;
  51. fl.l_len = len;
  52. switch (cmd)
  53. {
  54. case F_TEST:
  55. /* Test the lock: return 0 if FD is unlocked or locked by this process;
  56. return -1, set errno to EACCES, if another process holds the lock. */
  57. fl.l_type = F_RDLCK;
  58. if (fcntl (fd, F_GETLK, &fl) < 0)
  59. return -1;
  60. if (fl.l_type == F_UNLCK || fl.l_pid == getpid ())
  61. return 0;
  62. __set_errno(EACCES);
  63. return -1;
  64. case F_ULOCK:
  65. fl.l_type = F_UNLCK;
  66. cmd = F_SETLK;
  67. break;
  68. case F_LOCK:
  69. fl.l_type = F_WRLCK;
  70. cmd = F_SETLKW;
  71. break;
  72. case F_TLOCK:
  73. fl.l_type = F_WRLCK;
  74. cmd = F_SETLK;
  75. break;
  76. default:
  77. __set_errno(EINVAL);
  78. return -1;
  79. }
  80. return fcntl(fd, cmd, &fl);
  81. }
  82. libc_hidden_def(lockf64)