Move the repetitive NSS walking logic into an include file

[nss_nonlocal.git] / walk_nss.h

diff --git a/walk_nss.h b/walk_nss.h
new file mode 100644 (file)
index 0000000..93af177
--- /dev/null
+++ b/walk_nss.h
@@ -0,0 +1,87 @@
+/*
+ * 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 service_user *startp = NULL;
+    static void *fct_start = NULL;
+
+    service_user *nip;
+    union {
+       __typeof__(self) l;
+       void *ptr;
+    } fct;
+    int old_errno = errno;
+
+    if (fct_start == NULL &&
+       w.lookup(&startp, w.fct_name, &fct_start) != 0) {
+       *w.status = NSS_STATUS_UNAVAIL;
+       goto walk_nss_out;
+    }
+
+    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, 0) == 0);
+
+    if (w.buf != NULL && *w.status != NSS_STATUS_SUCCESS) {
+       free(*w.buf);
+       *w.buf = NULL;
+    }
+
+ walk_nss_out:
+    ;
+}