getpass.c 3.2 KB

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  1. /* Copyright (C) 1992,93,94,95,96,97,98,99 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 <stdio.h>
  16. #include <string.h>
  17. #include <termios.h>
  18. #include <unistd.h>
  19. #include <string.h>
  20. #if defined __USE_BSD || (defined __USE_XOPEN && !defined __USE_XOPEN2K)
  21. libc_hidden_proto(strlen)
  22. libc_hidden_proto(tcsetattr)
  23. libc_hidden_proto(tcgetattr)
  24. libc_hidden_proto(setvbuf)
  25. libc_hidden_proto(fopen)
  26. libc_hidden_proto(fclose)
  27. libc_hidden_proto(fileno)
  28. libc_hidden_proto(fflush)
  29. libc_hidden_proto(fgets)
  30. libc_hidden_proto(fputs)
  31. libc_hidden_proto(fputc)
  32. libc_hidden_proto(putc)
  33. libc_hidden_proto(__fputc_unlocked)
  34. /* It is desirable to use this bit on systems that have it.
  35. The only bit of terminal state we want to twiddle is echoing, which is
  36. done in software; there is no need to change the state of the terminal
  37. hardware. */
  38. #ifndef TCSASOFT
  39. #define TCSASOFT 0
  40. #endif
  41. #define PWD_BUFFER_SIZE 256
  42. char *
  43. getpass (prompt)
  44. const char *prompt;
  45. {
  46. FILE *in, *out;
  47. struct termios s, t;
  48. int tty_changed;
  49. static char buf[PWD_BUFFER_SIZE];
  50. int nread;
  51. /* Try to write to and read from the terminal if we can.
  52. If we can't open the terminal, use stderr and stdin. */
  53. in = fopen ("/dev/tty", "r+");
  54. if (in == NULL)
  55. {
  56. in = stdin;
  57. out = stderr;
  58. }
  59. else
  60. out = in;
  61. /* Turn echoing off if it is on now. */
  62. if (tcgetattr (fileno (in), &t) == 0)
  63. {
  64. /* Save the old one. */
  65. s = t;
  66. /* Tricky, tricky. */
  67. t.c_lflag &= ~(ECHO|ISIG);
  68. tty_changed = (tcsetattr (fileno (in), TCSAFLUSH|TCSASOFT, &t) == 0);
  69. if (in != stdin) {
  70. /* Disable buffering for read/write FILE to prevent problems with
  71. * fseek and buffering for read/write auto-transitioning. */
  72. setvbuf(in, NULL, _IONBF, 0);
  73. }
  74. }
  75. else
  76. tty_changed = 0;
  77. /* Write the prompt. */
  78. fputs(prompt, out);
  79. fflush(out);
  80. /* Read the password. */
  81. fgets (buf, PWD_BUFFER_SIZE-1, in);
  82. if (buf != NULL)
  83. {
  84. nread = strlen(buf);
  85. if (nread < 0)
  86. buf[0] = '\0';
  87. else if (buf[nread - 1] == '\n')
  88. {
  89. /* Remove the newline. */
  90. buf[nread - 1] = '\0';
  91. if (tty_changed)
  92. /* Write the newline that was not echoed. */
  93. putc('\n', out);
  94. }
  95. }
  96. /* Restore the original setting. */
  97. if (tty_changed) {
  98. (void) tcsetattr (fileno (in), TCSAFLUSH|TCSASOFT, &s);
  99. }
  100. if (in != stdin)
  101. /* We opened the terminal; now close it. */
  102. fclose (in);
  103. return buf;
  104. }
  105. #endif