Section (3) pam_start
creates the PAM context and initiates the PAM transaction. It
is the first of the PAM functions that needs to be called by
an application. The transaction state is contained entirely
within the structure identified by this handle, so it is
possible to have multiple transactions in parallel. But it is
not possible to use the same handle for different
transactions, a new one is needed for every new context.
argument specifies the name of the service to apply and will
be stored as PAM_SERVICE item in the new context. The policy
for the service will be read from the file
/etc/pam.d/service_name or, if that file
does not exist, from
The user argument can specify the name of the target user and will be stored as PAM_USER item. If the argument is NULL, the module has to ask for this item if necessary.
The pam_conversation argument points to a struct pam_conv describing the conversation function to use. An application must provide this for direct communication between a loaded module and the application.
Following a successful return (PAM_SUCCESS) the contents of pamh is a handle that contains the PAM context for successive calls to the PAM functions. In an error case is the content of pamh undefined.
The pam_handle_t is
a blind structure and the application should not attempt to
probe it directly for information. Instead the PAM library
provides the functions pam_set_item(3) and
pam_get_item(3). The PAM
handle cannot be used for mulitiple authentications at the
same time as long as
was not called on it before.
Memory buffer error.
Transaction was successful created.
System error, for example a NULL pointer was submitted instead of a pointer to data.