crypt_gensalt(3C)

NAME

     crypt_gensalt - generate salt string for string encoding

SYNOPSIS

     #include <crypt.h>

     char *crypt_gensalt(const char *oldsalt, const struct passwd
     *userinfo);

DESCRIPTION

     The  crypt_gensalt()  function  generates  the  salt  string
     required by crypt(3C).

     If oldsalt  is  NULL,  crypt_gensalt()  uses  the  algorithm
     defined  by  CRYPT_DEFAULT in /etc/security/policy.conf. See
     policy.conf(4).

     If oldsalt is non-null, crypt_gensalt()  determines  if  the
     algorithm  specified by oldsalt is allowable by checking the
     CRYPT_ALGORITHMS_ALLOW and CRYPT_ALGORITHMS_DEPRECATE  vari-
     ables  in  /etc/security/policy.conf.  If  the  algorithm is
     allowed,  crypt_gensalt()  loads  the   appropriate   shared
     library  and  calls crypt_gensalt_impl(3C). If the algorithm
     is not allowed or there is no entry for  it  in  crypt.conf,
     crypt_gensalt() uses the default algorithm.

     The mechanism just described provides  a  means  to  migrate
     users  to  new password hashing algorithms when the password
     is changed.

RETURN VALUES

     Upon  successful  completion,  crypt_gensalt()   returns   a
     pointer  to  the  new  salt.  Otherwise  a  null  pointer is
     returned and errno is set to indicate the error.

ERRORS

     The crypt_gensalt() function will fail if:

     EINVAL
           The configuration file crypt.conf contains an  invalid
           entry.

     ELIBACC
           The required shared library was not found.

     ENOMEM
           There is insufficient memory to perform hashing.

USAGE

     The value returned by  crypt_gensalt()  points  to  a  null-
     terminated  string. The caller of crypt_gensalt() is respon-
     sible for calling free(3C).
     Applications dealing with user authentication  and  password
     changing should not call crypt_gensalt() directly but should
     instead call the appropriate pam(3PAM) functions.

ATTRIBUTES

     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Evolving                    |
    |_____________________________|_____________________________|
    | MT-Level                    | MT-Safe                     |
    |_____________________________|_____________________________|

SEE ALSO

     passwd(1),        crypt(3C),         crypt_genhash_impl(3C),
     crypt_gensalt_impl(3C),    getpassphrase(3C),    malloc(3C),
     pam(3PAM), crypt.conf(4), passwd(4), policy.conf(4),  attri-
     butes(5)