NSS: Add option to expand homedir template format

LDAP server can contain template for home directory instead of plain string.
This patch adds new expand option "%H", which will be replaced with value
from configuration option homedir_substring (from sssd.conf)

Resolves:
https://fedorahosted.org/sssd/ticket/1853

3 files changed, 16 insertions, 2 deletions

diff --git a/src/responder/nss/nsssrv.c b/src/responder/nss/nsssrv.c
index e4896a79d..1f762cca8 100644
--- a/src/responder/nss/nsssrv.c
+++ b/src/responder/nss/nsssrv.c
@@ -291,6 +291,12 @@ static int nss_get_config(struct nss_ctx *nctx,
                             &nctx->default_shell);
     if (ret != EOK) goto done;
 
+    ret = confdb_get_string(cdb, nctx, CONFDB_NSS_CONF_ENTRY,
+                            CONFDB_NSS_HOMEDIR_SUBSTRING,
+                            CONFDB_DEFAULT_HOMEDIR_SUBSTRING,
+                            &nctx->homedir_substr);
+    if (ret != EOK) goto done;
+
     ret = 0;
 done:
     return ret;
diff --git a/src/responder/nss/nsssrv.h b/src/responder/nss/nsssrv.h
index a36589837..a5b946b7e 100644
--- a/src/responder/nss/nsssrv.h
+++ b/src/responder/nss/nsssrv.h
@@ -62,6 +62,7 @@ struct nss_ctx {
 
     char *override_homedir;
     char *fallback_homedir;
+    char *homedir_substr;
     char **allowed_shells;
     char *override_shell;
     char **vetoed_shells;
diff --git a/src/responder/nss/nsssrv_cmd.c b/src/responder/nss/nsssrv_cmd.c
index b47a1ded5..a168a3e5d 100644
--- a/src/responder/nss/nsssrv_cmd.c
+++ b/src/responder/nss/nsssrv_cmd.c
@@ -190,6 +190,13 @@ static const char *get_homedir_override(TALLOC_CTX *mem_ctx,
         return NULL;
     }
 
+    /* Check to see which homedir_prefix to use. */
+    if (dom->homedir_substr != NULL) {
+        homedir_ctx->config_homedir_substr = dom->homedir_substr;
+    } else if (nctx->homedir_substr != NULL) {
+        homedir_ctx->config_homedir_substr = nctx->homedir_substr;
+    }
+
     /* Check whether we are unconditionally overriding the server
      * for home directory locations.
      */
@@ -214,8 +221,8 @@ static const char *get_homedir_override(TALLOC_CTX *mem_ctx,
         }
     }
 
-    /* Return the value we got from the provider */
-    return talloc_strdup(mem_ctx, homedir);
+    /* Provider can also return template, try to expand it.*/
+    return expand_homedir_template(mem_ctx, homedir, homedir_ctx);
 }
 
 static const char *get_shell_override(TALLOC_CTX *mem_ctx,