gen/getpass.3

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  32 .\"     @(#)getpass.3   8.1 (Berkeley) 6/4/93
  33 .\" $FreeBSD: src/lib/libc/gen/getpass.3,v 1.9 2001/10/01 16:08:51 ru Exp $
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  35 .Dd June 4, 1993
  36 .Dt GETPASS 3
  37 .Os
  38 .Sh NAME
  39 .Nm getpass
  40 .Nd get a password
  41 .Sh LIBRARY
  42 .Lb libc
  43 .Sh SYNOPSIS
  44 .In pwd.h
  45 .In unistd.h
  46 .Ft char *
  47 .Fn getpass "const char *prompt"
  48 .Sh DESCRIPTION
  49 The
  50 .Fn getpass
  51 function displays a prompt to, and reads in a password from,
  52 .Pa /dev/tty .
  53 If this file is not accessible,
  54 .Fn getpass
  55 displays the prompt on the standard error output and reads from the standard
  56 input.
  57 .Pp
  58 The password may be up to _PASSWORD_LEN (currently 128)
  59 characters in length.
  60 Any additional
  61 characters and the terminating newline character are discarded.
  62 .Pp
  63 The
  64 .Fn getpass
  65 function turns off character echoing while reading the password.
  66 .Sh RETURN VALUES
  67 The
  68 .Fn getpass
  69 function returns a pointer to the null terminated password.
  70 .Sh FILES
  71 .Bl -tag -width /dev/tty -compact
  72 .It Pa /dev/tty
  73 .El
  74 .Sh SEE ALSO
  75 .Xr crypt 3
  76 .Sh HISTORY
  77 A
  78 .Fn getpass
  79 function appeared in
  80 .At v7 .
  81 .Sh BUGS
  82 The
  83 .Fn getpass
  84 function leaves its result in an internal static object and returns
  85 a pointer to that object.
  86 Subsequent calls to
  87 .Fn getpass
  88 will modify the same object.
  89 .Pp
  90 The calling process should zero the password as soon as possible to
  91 avoid leaving the cleartext password visible in the process's address
  92 space.
  93 .Pp
  94 Upon receipt of a SIGTSTP, the input buffer will be flushed, so any
  95 partially typed password must be retyped when the process
  96 continues.