grantpt.c 2.4 KB

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  1. /* Copyright (C) 1998, 1999 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 <limits.h>
  16. #include <stdlib.h>
  17. /* If ASSUME_DEVPTS is defined, grantpt() reduces to a stub since we
  18. assume that the devfs/devpts filesystem automatically manages the
  19. permissions. */
  20. #if !defined ASSUME_DEVPTS
  21. #include <sys/statfs.h>
  22. /* Constant that identifies the `devpts' filesystem. */
  23. #define DEVPTS_SUPER_MAGIC 0x1cd1
  24. /* Constant that identifies the `devfs' filesystem. */
  25. #define DEVFS_SUPER_MAGIC 0x1373
  26. /* Prototype for function that changes ownership and access permission
  27. for slave pseudo terminals that do not live on a `devpts'
  28. filesystem. */
  29. int __unix_grantpt (int fd);
  30. /* Prototype for private function that gets the name of the slave
  31. pseudo terminal in a safe way. */
  32. static int pts_name (int fd, char **pts, size_t buf_len);
  33. #endif
  34. /* Change the ownership and access permission of the slave pseudo
  35. terminal associated with the master pseudo terminal specified
  36. by FD. */
  37. int
  38. grantpt (int fd)
  39. {
  40. #if !defined ASSUME_DEVPTS
  41. struct statfs fsbuf;
  42. # ifdef PATH_MAX
  43. char _buf[PATH_MAX];
  44. # else
  45. char _buf[512];
  46. # endif
  47. char *buf = _buf;
  48. if (pts_name (fd, &buf, sizeof (_buf)))
  49. return -1;
  50. if (statfs (buf, &fsbuf) < 0)
  51. return -1;
  52. /* If the slave pseudo terminal lives on a `devpts' filesystem, the
  53. ownership and access permission are already set. */
  54. if (fsbuf.f_type != DEVPTS_SUPER_MAGIC && fsbuf.f_type != DEVFS_SUPER_MAGIC)
  55. return __unix_grantpt (fd);
  56. #endif
  57. return 0;
  58. }
  59. #if !defined ASSUME_DEVPTS
  60. # define grantpt __unix_grantpt
  61. # include "unix_grantpt.c"
  62. #endif