getpt.c 3.6 KB

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  1. /* Copyright (C) 1998, 1999, 2001 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. Contributed by Zack Weinberg <zack@rabi.phys.columbia.edu>, 1998.
  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. The GNU C Library is distributed in the hope that it will be useful,
  9. but WITHOUT ANY WARRANTY; without even the implied warranty of
  10. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11. Lesser General Public License for more details.
  12. You should have received a copy of the GNU Lesser General Public
  13. License along with the GNU C Library; if not, write to the Free
  14. Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  15. 02111-1307 USA. */
  16. #include <errno.h>
  17. #include <fcntl.h>
  18. #include <stdlib.h>
  19. #include <stdbool.h>
  20. #include <unistd.h>
  21. #include <paths.h>
  22. #include <sys/statfs.h>
  23. extern __typeof(statfs) __libc_statfs;
  24. #if !defined __ASSUME_DEVPTS__
  25. /* Constant that identifies the `devpts' filesystem. */
  26. # define DEVPTS_SUPER_MAGIC 0x1cd1
  27. /* Constant that identifies the `devfs' filesystem. */
  28. # define DEVFS_SUPER_MAGIC 0x1373
  29. #endif
  30. /* Path to the master pseudo terminal cloning device. */
  31. #define _PATH_DEVPTMX _PATH_DEV "ptmx"
  32. /* Directory containing the UNIX98 pseudo terminals. */
  33. #define _PATH_DEVPTS _PATH_DEV "pts"
  34. #if !defined __UNIX98PTY_ONLY__ && defined __UCLIBC_HAS_GETPT__
  35. /* Prototype for function that opens BSD-style master pseudo-terminals. */
  36. static __inline__ int __bsd_getpt (void);
  37. #endif
  38. /* Open a master pseudo terminal and return its file descriptor. */
  39. static int
  40. __posix_openpt (int flags)
  41. {
  42. #define have_no_dev_ptmx (1<<0)
  43. #define devpts_mounted (1<<1)
  44. #if !defined __UNIX98PTY_ONLY__
  45. static smallint _state;
  46. #endif
  47. int fd;
  48. #if !defined __UNIX98PTY_ONLY__
  49. if (!(_state & have_no_dev_ptmx))
  50. #endif
  51. {
  52. fd = open (_PATH_DEVPTMX, flags);
  53. if (fd != -1)
  54. {
  55. #if defined __ASSUME_DEVPTS__
  56. return fd;
  57. #else
  58. struct statfs fsbuf;
  59. /* Check that the /dev/pts filesystem is mounted
  60. or if /dev is a devfs filesystem (this implies /dev/pts). */
  61. if (
  62. #if !defined __UNIX98PTY_ONLY__
  63. (_state & devpts_mounted) ||
  64. #endif
  65. (__libc_statfs (_PATH_DEVPTS, &fsbuf) == 0
  66. && fsbuf.f_type == DEVPTS_SUPER_MAGIC)
  67. || (__libc_statfs (_PATH_DEV, &fsbuf) == 0
  68. && fsbuf.f_type == DEVFS_SUPER_MAGIC))
  69. {
  70. /* Everything is ok. */
  71. #if !defined __UNIX98PTY_ONLY__
  72. _state |= devpts_mounted;
  73. #endif
  74. return fd;
  75. }
  76. /* If /dev/pts is not mounted then the UNIX98 pseudo terminals
  77. are not usable. */
  78. close (fd);
  79. #if !defined __UNIX98PTY_ONLY__
  80. _state |= have_no_dev_ptmx;
  81. #endif
  82. #endif
  83. }
  84. else
  85. {
  86. #if !defined __UNIX98PTY_ONLY__
  87. if (errno == ENOENT || errno == ENODEV)
  88. _state |= have_no_dev_ptmx;
  89. else
  90. #endif
  91. return -1;
  92. }
  93. }
  94. #if !defined __UNIX98PTY_ONLY__ && defined __UCLIBC_HAS_GETPT__
  95. /* If we have no ptmx then ignore flags and use the fallback. */
  96. if (_state & have_no_dev_ptmx)
  97. return __bsd_getpt();
  98. #endif
  99. return -1;
  100. }
  101. strong_alias(__posix_openpt,posix_openpt)
  102. #undef have_no_dev_ptmx
  103. #undef devpts_mounted
  104. #if defined __USE_GNU && defined __UCLIBC_HAS_GETPT__
  105. int getpt (void)
  106. {
  107. return __posix_openpt(O_RDWR);
  108. }
  109. #if !defined __UNIX98PTY_ONLY__ && defined __UCLIBC_HAS_GETPT__
  110. # define PTYNAME1 "pqrstuvwxyzabcde";
  111. # define PTYNAME2 "0123456789abcdef";
  112. # define __getpt __bsd_getpt
  113. # include "bsd_getpt.c"
  114. #endif
  115. #endif /* GNU && __UCLIBC_HAS_GETPT__ */