source: trunk/debathena/debathena/libnss-nonlocal/walk_nss.h @ 26035

/*
 * walk_nss.h
 * NSS walking template for nss_nonlocal proxy
 *
 * Copyright © 2011 Anders Kaseorg <andersk@mit.edu> and Tim Abbott
 * <tabbott@mit.edu>
 *
 * This file is part of nss_nonlocal.
 *
 * nss_nonlocal is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * nss_nonlocal is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with nss_nonlocal; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301  USA
 */

{
    static bool initialized = false;
    static service_user *startp;
    static void *fct_start;

    service_user *nip;
    union {
        __typeof__(self) l;
        void *ptr;
    } fct;
    int old_errno = errno;

    if (!initialized) {
        if (w.lookup(&startp, w.fct_name, &fct_start) != 0) {
            *w.status = NSS_STATUS_UNAVAIL;
            goto walk_nss_out;
        }
        __sync_synchronize();
        initialized = true;
    }

    nip = startp;
    fct.ptr = fct_start;

    if (w.buf != NULL) {
        *w.buf = malloc(*w.buflen);
        errno = old_errno;
        if (*w.buf == NULL) {
            *w.status = NSS_STATUS_TRYAGAIN;
            *w.errnop = ENOMEM;
            goto walk_nss_out;
        }
    }

    do {
    walk_nss_morebuf:
        if (fct.ptr == NULL)
            *w.status = NSS_STATUS_UNAVAIL;
        else if (self != NULL && fct.l == self)
            *w.status = NSS_STATUS_NOTFOUND;
        else
            *w.status = DL_CALL_FCT(fct.l, args);
        if (*w.status == NSS_STATUS_TRYAGAIN &&
            w.errnop != NULL && *w.errnop == ERANGE) {
            if (w.buf == NULL)
                break;
            free(*w.buf);
            *w.buflen *= 2;
            *w.buf = malloc(*w.buflen);
            errno = old_errno;
            if (*w.buf == NULL) {
                *w.errnop = ENOMEM;
                goto walk_nss_out;
            }
            goto walk_nss_morebuf;
        }
    } while (__nss_next(&nip, w.fct_name, &fct.ptr, *w.status, w.all_values) ==
             0);

    if (w.buf != NULL && *w.status != NSS_STATUS_SUCCESS) {
        free(*w.buf);
        *w.buf = NULL;
    }

 walk_nss_out:
    ;
}