Display a prompt and accept the users response without echoing it to the terminal. This is commonly used for passwords.
Display a prompt and accept the users response, echoing it to the terminal. This is commonly used for login names and one-time passphrases.
Display an error message.
Display an informational message.
In each case, the prompt or message to display is pointed to by the msg member of .Vt struct pam_message . It can be up to PAM_MAX_MSG_SIZE characters long, including the terminating NUL.
On success, the conversation function should allocate and fill a contiguous array of .Vt struct pam_response , one for each message that was passed in. A pointer to the users response to each message (or NULL in the case of informational or error messages) should be stored in the resp member of the corresponding .Vt struct pam_response . Each response can be up to PAM_MAX_RESP_SIZE characters long, including the terminating NUL.
The resp_retcode member of .Vt struct pam_response is unused and should be set to zero.
The conversation function should store a pointer to this array in the location pointed to by its third argument. It is the callers responsibility to release both this array and the responses themselves, using free(3). It is the conversation functions responsibility to ensure that it is legal to do so.
The appdata_ptr member of .Vt struct pam_conv is passed unmodified to the conversation function as its fourth and final argument.
On failure, the conversation function should release any resources it has allocated, and return one of the predefined PAM error codes.