getpt.c 3.0 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 <unistd.h>
  20. #include <paths.h>
  21. libc_hidden_proto(open)
  22. libc_hidden_proto(close)
  23. #if !defined __ASSUME_DEVPTS__
  24. # include <sys/statfs.h>
  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__
  35. /* Prototype for function that opens BSD-style master pseudo-terminals. */
  36. extern int __bsd_getpt (void) attribute_hidden;
  37. #endif
  38. /* Open a master pseudo terminal and return its file descriptor. */
  39. int
  40. getpt (void)
  41. {
  42. #if !defined __UNIX98PTY_ONLY__
  43. static smallint have_no_dev_ptmx;
  44. #endif
  45. int fd;
  46. #if !defined __UNIX98PTY_ONLY__
  47. if (!have_no_dev_ptmx)
  48. #endif
  49. {
  50. fd = open (_PATH_DEVPTMX, O_RDWR);
  51. if (fd != -1)
  52. {
  53. #if defined __ASSUME_DEVPTS__
  54. return fd;
  55. #else
  56. struct statfs fsbuf;
  57. static smallint devpts_mounted;
  58. /* Check that the /dev/pts filesystem is mounted
  59. or if /dev is a devfs filesystem (this implies /dev/pts). */
  60. if (devpts_mounted
  61. || (statfs (_PATH_DEVPTS, &fsbuf) == 0
  62. && fsbuf.f_type == DEVPTS_SUPER_MAGIC)
  63. || (statfs (_PATH_DEV, &fsbuf) == 0
  64. && fsbuf.f_type == DEVFS_SUPER_MAGIC))
  65. {
  66. /* Everything is ok. */
  67. devpts_mounted = 1;
  68. return fd;
  69. }
  70. /* If /dev/pts is not mounted then the UNIX98 pseudo terminals
  71. are not usable. */
  72. close (fd);
  73. #if !defined __UNIX98PTY_ONLY__
  74. have_no_dev_ptmx = 1;
  75. #endif
  76. #endif
  77. }
  78. else
  79. {
  80. #if !defined __UNIX98PTY_ONLY__
  81. if (errno == ENOENT || errno == ENODEV)
  82. have_no_dev_ptmx = 1;
  83. else
  84. #endif
  85. return -1;
  86. }
  87. }
  88. #if !defined __UNIX98PTY_ONLY__
  89. return __bsd_getpt ();
  90. #endif
  91. }
  92. #if !defined __UNIX98PTY_ONLY__
  93. # define PTYNAME1 "pqrstuvwxyzabcde";
  94. # define PTYNAME2 "0123456789abcdef";
  95. # define __getpt __bsd_getpt
  96. # include "bsd_getpt.c"
  97. #endif