getpass - get a password

Attributes

       For an explanation of the terms used in this section, see attributes(7).
       ┌──────────────────────────────────────────────────────────────────────┬───────────────┬────────────────┐
       │ Interface                                                            │ Attribute     │ Value          │
       ├──────────────────────────────────────────────────────────────────────┼───────────────┼────────────────┤
       │ getpass()                                                            │ Thread safety │ MT-Unsafe term │
       └──────────────────────────────────────────────────────────────────────┴───────────────┴────────────────┘

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.

Description

       This  function  is  obsolete.   Do  not  use  it.  See NOTES.  If you want to read input without terminal
       echoing enabled, see the description of the ECHO flag in termios(3).

       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.

Errors

ENXIO  The process does not have a controlling terminal.

Files

/dev/tty

History

       Version 7 AT&T UNIX.  Present in SUSv2, but marked LEGACY.  Removed in POSIX.1-2001.

Library

       Standard C library (libc, -lc)

Name

       getpass - get a password

Notes

       You should use instead readpassphrase(3bsd), provided by libbsd.

       In  the  GNU  C library implementation, 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 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().   The  glibc  version  accepts  _SC_PASS_MAX  and
       returns BUFSIZ (e.g., 8192).

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 to indicate the  error,  and
       NULL is returned.

Standards

       None.

Synopsis

#include<unistd.h>[[deprecated]]char*getpass(constchar*prompt);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       getpass():
           Since glibc 2.2.2:
               _XOPEN_SOURCE && ! (_POSIX_C_SOURCE >= 200112L)
                   || /* glibc >= 2.19: */ _DEFAULT_SOURCE
                   || /* glibc <= 2.19: */ _BSD_SOURCE
           Before glibc 2.2.2:
               none