gen/FreeBSD/getpass.3

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  28 .\"     @(#)getpass.3   8.1 (Berkeley) 6/4/93
  29 .\" $FreeBSD: src/lib/libc/gen/getpass.3,v 1.12 2007/01/09 00:27:54 imp Exp $
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  31 .Dd June 4, 1993
  32 .Dt GETPASS 3
  33 .Os
  34 .Sh NAME
  35 .Nm getpass
  36 .Nd get a password
  37 .Sh LIBRARY
  38 .Lb libc
  39 .Sh SYNOPSIS
  40 .In pwd.h
  41 .In unistd.h
  42 .Ft char *
  43 .Fn getpass "const char *prompt"
  44 .Sh DESCRIPTION
  45 The
  46 .Fn getpass
  47 function displays a prompt to, and reads in a password from,
  48 .Pa /dev/tty .
  49 If this file is not accessible,
  50 .Fn getpass
  51 displays the prompt on the standard error output and reads from the standard
  52 input.
  53 .Pp
  54 The password may be up to _PASSWORD_LEN (currently 128)
  55 characters in length.
  56 Any additional
  57 characters and the terminating newline character are discarded.
  58 .Pp
  59 The
  60 .Fn getpass
  61 function turns off character echoing while reading the password.
  62 .Sh RETURN VALUES
  63 The
  64 .Fn getpass
  65 function returns a pointer to the null terminated password.
  66 .Sh FILES
  67 .Bl -tag -width /dev/tty -compact
  68 .It Pa /dev/tty
  69 .El
  70 .Sh SEE ALSO
  71 .Xr crypt 3 ,
  72 .Xr readpassphrase 3
  73 .Sh HISTORY
  74 A
  75 .Fn getpass
  76 function appeared in
  77 .At v7 .
  78 .Sh BUGS
  79 The
  80 .Fn getpass
  81 function leaves its result in an internal static object and returns
  82 a pointer to that object.
  83 Subsequent calls to
  84 .Fn getpass
  85 will modify the same object.
  86 .Pp
  87 The calling process should zero the password as soon as possible to
  88 avoid leaving the cleartext password visible in the process's address
  89 space.
  90 .Pp
  91 Upon receipt of a SIGTSTP, the input buffer will be flushed, so any
  92 partially typed password must be retyped when the process
  93 continues.