GETPASS(3)                                          Linux Programmer's Manual                                         GETPASS(3)



NAME
       getpass - get a password

SYNOPSIS
       #include <unistd.h>

       char *getpass( const char *prompt);

DESCRIPTION
       This function is obsolete.  Do not use it.

       The  getpass()  function  opens  /dev/tty (the controlling terminal of the process), outputs the string prompt, turns off
       echoing, reads one line (the "password"), restores the terminal state and closes /dev/tty again.

RETURN VALUE
       The function getpass() returns a pointer to a static buffer containing (the first PASS_MAX bytes of) the password without
       the  trailing  newline, terminated by a null byte ('\0').  This buffer may be overwritten by a following call.  On error,
       the terminal state is restored, errno is set appropriately, and NULL is returned.

ERRORS
       The function may fail if

       ENXIO  The process does not have a controlling terminal.

FILES
       /dev/tty

CONFORMING TO
       Present in SUSv2, but marked LEGACY.  Removed in POSIX.1-2001.

NOTES
       For libc4 and libc5, the prompt is not written to /dev/tty but to stderr.  Moreover, if /dev/tty cannot  be  opened,  the
       password  is  read  from  stdin.   The  static buffer has length 128 so that only the first 127 bytes of the password are
       returned.  While reading the password, signal generation (SIGINT, SIGQUIT, SIGSTOP, SIGTSTP) is disabled and  the  corre-
       sponding  characters  (usually  control-C,  control-\,  control-Z and control-Y) are transmitted as part of the password.
       Since libc 5.4.19 also line editing is disabled, so that also backspace and the like will be seen as part  of  the  pass-
       word.

       For  glibc2, if /dev/tty cannot be opened, the prompt is written to stderr and the password is read from stdin.  There is
       no limit on the length of the password.  Line editing is not disabled.

       According to the SUSv2, the value of PASS_MAX must be defined in <limits.h> in case it is smaller than 8, and can in  any
       case  be  obtained  using sysconf(_SC_PASS_MAX).  However, POSIX.2 withdraws the constants PASS_MAX and _SC_PASS_MAX, and
       the function getpass().  Libc4 and libc5 have never supported PASS_MAX or _SC_PASS_MAX.  Glibc2 accepts _SC_PASS_MAX  and
       returns BUFSIZ (e.g., 8192).

BUGS
       The  calling  process should zero the password as soon as possible to avoid leaving the cleartext password visible in the
       process's address space.

SEE ALSO
       crypt(3)

COLOPHON
       This page is part of release 3.25 of the Linux man-pages project.  A description of the project,  and  information  about
       reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.



Linux                                                      2000-12-05                                                 GETPASS(3)