getpt.c 3.5 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. libc_hidden_proto(__libc_statfs)
  25. libc_hidden_proto(open)
  26. libc_hidden_proto(close)
  27. #if !defined __ASSUME_DEVPTS__
  28. # include <sys/statfs.h>
  29. /* Constant that identifies the `devpts' filesystem. */
  30. # define DEVPTS_SUPER_MAGIC 0x1cd1
  31. /* Constant that identifies the `devfs' filesystem. */
  32. # define DEVFS_SUPER_MAGIC 0x1373
  33. #endif
  34. /* Path to the master pseudo terminal cloning device. */
  35. #define _PATH_DEVPTMX _PATH_DEV "ptmx"
  36. /* Directory containing the UNIX98 pseudo terminals. */
  37. #define _PATH_DEVPTS _PATH_DEV "pts"
  38. #if !defined __UNIX98PTY_ONLY__ && defined __UCLIBC_HAS_GETPT__
  39. /* Prototype for function that opens BSD-style master pseudo-terminals. */
  40. extern int __bsd_getpt (void) attribute_hidden;
  41. #endif
  42. /* Open a master pseudo terminal and return its file descriptor. */
  43. int
  44. posix_openpt (int flags)
  45. {
  46. #define have_no_dev_ptmx (1<<0)
  47. #define devpts_mounted (1<<1)
  48. #if !defined __UNIX98PTY_ONLY__
  49. static smallint _state;
  50. #endif
  51. int fd;
  52. #if !defined __UNIX98PTY_ONLY__
  53. if (!(_state & have_no_dev_ptmx))
  54. #endif
  55. {
  56. fd = open (_PATH_DEVPTMX, flags);
  57. if (fd != -1)
  58. {
  59. #if defined __ASSUME_DEVPTS__
  60. return fd;
  61. #else
  62. struct statfs fsbuf;
  63. /* Check that the /dev/pts filesystem is mounted
  64. or if /dev is a devfs filesystem (this implies /dev/pts). */
  65. if ((_state & devpts_mounted)
  66. || (__libc_statfs (_PATH_DEVPTS, &fsbuf) == 0
  67. && fsbuf.f_type == DEVPTS_SUPER_MAGIC)
  68. || (__libc_statfs (_PATH_DEV, &fsbuf) == 0
  69. && fsbuf.f_type == DEVFS_SUPER_MAGIC))
  70. {
  71. /* Everything is ok. */
  72. _state |= devpts_mounted;
  73. return fd;
  74. }
  75. /* If /dev/pts is not mounted then the UNIX98 pseudo terminals
  76. are not usable. */
  77. close (fd);
  78. #if !defined __UNIX98PTY_ONLY__
  79. _state |= have_no_dev_ptmx;
  80. #endif
  81. #endif
  82. }
  83. else
  84. {
  85. #if !defined __UNIX98PTY_ONLY__
  86. if (errno == ENOENT || errno == ENODEV)
  87. _state |= have_no_dev_ptmx;
  88. else
  89. #endif
  90. return -1;
  91. }
  92. }
  93. return -1;
  94. }
  95. #undef have_no_dev_ptmx
  96. #undef devpts_mounted
  97. #if defined __USE_GNU && defined __UCLIBC_HAS_GETPT__
  98. int
  99. getpt (void)
  100. {
  101. int fd = posix_openpt(O_RDWR);
  102. #if !defined __UNIX98PTY_ONLY__
  103. if (fd == -1)
  104. fd = __bsd_getpt();
  105. #endif
  106. return fd;
  107. }
  108. #if !defined __UNIX98PTY_ONLY__
  109. # define PTYNAME1 "pqrstuvwxyzabcde";
  110. # define PTYNAME2 "0123456789abcdef";
  111. # define __getpt __bsd_getpt
  112. # include "bsd_getpt.c"
  113. #endif
  114. #endif /* GNU && __UCLIBC_HAS_GETPT__ */