/*
 * 
 * k5passwd
 * 
 * Changes your password in the Kerberos V5. This should have been
 * part of the kadm stuff but we're forced to build a nicer API on top
 * of the calls they provide.
 * 
 */

#ifdef KRB5

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "krb5.h"
#include "com_err.h"
#include "adm.h"
#include "adm_proto.h"

static const char *kadm_replies[] = {
  "Operation successful",             	/* KRB5_ADM_SUCCESS */
  "Command not recognized",           	/* KRB5_ADM_CMD_UNKNOWN */
  "Password unacceptable to server",  	/* KRB5_ADM_PW_UNACCEPT */
  "Old password incorrect",           	/* KRB5_ADM_BAD_PW */
  "Invalid ticket (TKT_FLAG_INITIAL not set)",/* KRB5_ADM_NOT_IN_TKT */
  "Server refused password change",   	/* KRB5_ADM_CANT_CHANGE */
  "Language not supported",		/* KRB5_ADM_LANG_NOT_SUPPORTED */
};

static const char *kadm_replies_unknown = "UNKNOWN ERROR";
static char errbuf[1024];		/* For response from kadm */

/*
 * get_admin_response
 * 
 * Builds into a static buffer the replies sent back by the admin server.
 */
static char *
get_admin_response(krb5_int32  status,		/* Type of error */
		   krb5_int32  nreplies,	/* Size of reply */
		   krb5_data   *reply)		/* Buffer of messages */
{
  char *ptr;					/* For building the response */
  char *end = errbuf + sizeof (errbuf);		/* So we don't overflow */
  int i;					/* Index */
  int n;					/* Length */

  if (status <= KRB5_ADM_LANG_NOT_SUPPORTED)	/* Is it of a known type??? */
    strcpy (errbuf, kadm_replies[status]);
  else
    strcpy (errbuf, kadm_replies_unknown);	/* Unknown error type */
  ptr = errbuf + strlen (errbuf);		/* Point at the end */

  if (nreplies > 0) {				/* Are there more message? */
    *ptr++ = ':';
    *ptr = '\0';
  }

  for (i = 0; i < nreplies; ++i) {	/* Append additional messages */
    *ptr++ = '\n';

    n = reply[i].length;			/* Easier to work with */
    if (ptr + n + 2 >= errbuf)			/* Check for overflow */
      break;
    memcpy (ptr, reply[i].data, n);		/* Add the message */
    ptr += n;					/* Point to the end */
    *ptr = '\0';
  }

  return errbuf;
}

/*
 * keyadmin_send_recieve
 * 
 * Sends a command to the key admin and reads the reply.
 */
static krb5_error_code
keyadmin_send_receive(krb5_context 		k5context,
		      int 		       *conn_socket,
		      krb5_auth_context 	auth_context,
		      krb5_int32 		nargs,
		      krb5_data 	       *arglist,
		      krb5_int32 	       *cmd_stat,
		      krb5_int32 	       *nreplies,
		      krb5_data 	      **reply)
{
  krb5_error_code	kret;
  char foo[1024];
  int i;

  kret = krb5_send_adm_cmd (k5context, conn_socket, auth_context,
			    nargs, arglist);

  if (! kret)
    kret = krb5_read_adm_reply (k5context, conn_socket, auth_context,
				cmd_stat, nreplies, reply);

  return kret;
}


/*
 * k5_change_password
 * 
 * Bundles all the crud needed to change the password into one file.
 */
krb5_error_code
k5_change_password (krb5_context k5context, char *user, char *realm,
		    char *opasswd, char *npasswd, char **text)
{
  krb5_error_code	kret, kret2;
  krb5_auth_context	auth_context;
  krb5_ccache		ccache;
  int			conn_socket;	/* Socket for talking over */
  krb5_int32		nreplies;
  krb5_data		data[3];
  krb5_data  	       *reply;
  krb5_int32		status;
  char 		       *name;

  *text = NULL;					/* Be safe */
  name = malloc(strlen(user) + strlen(realm) + 2);
  if (name == NULL)
    return ENOMEM;
  sprintf(name, "%s@%s", user, realm);
  ccache = (krb5_ccache)NULL;

  /*
   * Establish the connection.
   */
  kret = krb5_adm_connect(k5context, name, NULL, opasswd, &conn_socket,
			  &auth_context, &ccache, "kadm.tk", 0);
  if (kret)
    goto done;

  /*
   * Check to see if it's an acceptable password
   */
  data[0].data = KRB5_ADM_CHECKPW_CMD;
  data[0].length = strlen (data[0].data);
  data[1].data = npasswd;
  data[1].length = strlen (npasswd);

  kret = keyadmin_send_receive (k5context, &conn_socket, auth_context,
				2, data, &status, &nreplies, &reply);
  if (kret) 					/* Some external error */
    goto cleanup;

  if (status != KRB5_ADM_SUCCESS) {			/* Some problem??? */
    kret = status;
    *text = get_admin_response (status, nreplies, reply);
    krb5_free_adm_data (k5context, nreplies, reply);

    goto quit;
  }
  krb5_free_adm_data (k5context, nreplies, reply);

  /*
   * The new password is ok, so now actually change the password
   */
  data[0].data = KRB5_ADM_CHANGEPW_CMD;
  data[0].length = strlen (data[0].data);
  data[1].data = opasswd;
  data[1].length = strlen (opasswd);
  data[2].data = npasswd;
  data[2].length = strlen (npasswd);

  kret = keyadmin_send_receive (k5context, &conn_socket, auth_context,
				3, data, &status, &nreplies, &reply);
  if (kret)
    goto cleanup;

  if (status != KRB5_ADM_SUCCESS) {
    kret = status;
    *text = get_admin_response (status, nreplies, reply);
    krb5_free_adm_data (k5context, nreplies, reply);

    goto quit;
  }

  krb5_free_adm_data (k5context, nreplies, reply);
  /*
   * Need to send quit command.
   */
quit:
  data[0].data = KRB5_ADM_QUIT_CMD;
  data[0].length = strlen (data[0].data);
  
  kret2 = keyadmin_send_receive (k5context, &conn_socket, auth_context,
				 1, data, &status, &nreplies, &reply);
  if (kret2) {
    if (! kret)
      kret = kret2;
  } else if (status != KRB5_ADM_SUCCESS) {
    if (! kret)
      kret = status;
    if (*text == NULL)
      *text = get_admin_response (status, nreplies, reply);
  }
  krb5_free_adm_data (k5context, nreplies, reply);

cleanup:
  krb5_adm_disconnect (k5context, &conn_socket, auth_context, ccache);

done:
  free (name);

  return kret;
}

#endif /* KRB5 */