The
pam_authenticate function attempts to authenticate the user associated with the pam context specified by the
pamh argument.
The application is free to call
pam_authenticate as many times as it wishes, but some modules may maintain an internal retry counter and return
PAM_MAXTRIES when it exceeds some preset or hardcoded limit.
The
flags argument is the binary or of zero or more of the following values:
PAM_SILENT
Do not emit any messages.
PAM_DISALLOW_NULL_AUTHTOK
Fail if the user's authentication token is null.
If any other bits are set,
pam_authenticate will return
PAM_SYMBOL_ERR.