Allow default options in /etc/exports

  Implement default options in /etc/exports, to fix a long-standing wishlist
  bug in Debian. (The user claims the syntax matches that of OpenBSD.) This
  makes it possible to write "/srv/www -sync,no_subtree_check host1 host2 host3"
  instead of having to write (sync,no_subtree_check) over and over and over
  again, driving the administrator slowly mad. Such option lines can be
  placed anywhere on the line, and affects anything after them (I do not
  know if OpenBSD allows this). The patch is slightly convoluted in order to
  avoid triggering spurious warnings; for instance, we want
  "/srv/www -sync host1" to trigger a warning, but not "/srv/www
  -sync,no_subtree_check host1" or "/srv/www -sync host1(no_subtree_check)".

  There was also a suggestion for a truly global (ie. per-file) option list,
  but this seemed like the safest bet, given that it matches that of other
  implementations.

  Also, the man page is updated with information on the new possibilities,
  and an example.

Signed-off-by: Steinar H. Gunderson <sesse@debian.org>
Signed-off-by: Neil Brown <neilb@suse.de>

1 files changed, 54 insertions, 28 deletions

diff --git a/support/nfs/exports.c b/support/nfs/exports.c
index 2d31781..9b010dc 100644
--- a/support/nfs/exports.c
+++ b/support/nfs/exports.c
@@ -39,12 +39,13 @@ int export_errno;
 static char	*efname = NULL;
 static XFILE	*efp = NULL;
 static int	first;
+static int	has_default_opts, has_default_subtree_opts;
 static int	*squids = NULL, nsquids = 0,
 		*sqgids = NULL, nsqgids = 0;
 
 static int	getexport(char *exp, int len);
 static int	getpath(char *path, int len);
-static int	parseopts(char *cp, struct exportent *ep, int warn);
+static int	parseopts(char *cp, struct exportent *ep, int warn, int *had_subtree_opt_ptr);
 static int	parsesquash(char *list, int **idp, int *lenp, char **ep);
 static int	parsenum(char **cpp);
 static int	parsemaptype(char *type);
@@ -68,7 +69,7 @@ setexportent(char *fname, char *type)
 struct exportent *
 getexportent(int fromkernel, int fromexports)
 {
-	static struct exportent	ee;
+	static struct exportent	ee, def_ee;
 	char		exp[512], *hostname;
 	char		rpath[MAXPATHLEN+1];
 	char		*opt, *sp;
@@ -78,31 +79,36 @@ getexportent(int fromkernel, int fromexports)
 		return NULL;
 
 	freesquash();
-	ee.e_flags = EXPORT_DEFAULT_FLAGS;
-	/* some kernels assume the default is sync rather than
-	 * async.  More recent kernels always report one or other,
-	 * but this test makes sure we assume same as kernel
-	 * Ditto for wgather
-	 */
-	if (fromkernel) {
-		ee.e_flags &= ~NFSEXP_ASYNC;
-		ee.e_flags &= ~NFSEXP_GATHERED_WRITES;
-	}
-	ee.e_maptype = CLE_MAP_IDENT;
-	ee.e_anonuid = 65534;
-	ee.e_anongid = 65534;
-	ee.e_squids = NULL;
-	ee.e_sqgids = NULL;
-	ee.e_mountpoint = NULL;
-	ee.e_nsquids = 0;
-	ee.e_nsqgids = 0;
 
 	if (first || (ok = getexport(exp, sizeof(exp))) == 0) {
-		ok = getpath(ee.e_path, sizeof(ee.e_path));
+		has_default_opts = 0;
+		has_default_subtree_opts = 0;
+	
+		def_ee.e_flags = EXPORT_DEFAULT_FLAGS;
+		/* some kernels assume the default is sync rather than
+		 * async.  More recent kernels always report one or other,
+		 * but this test makes sure we assume same as kernel
+		 * Ditto for wgather
+		 */
+		if (fromkernel) {
+			def_ee.e_flags &= ~NFSEXP_ASYNC;
+			def_ee.e_flags &= ~NFSEXP_GATHERED_WRITES;
+		}
+		def_ee.e_maptype = CLE_MAP_IDENT;
+		def_ee.e_anonuid = 65534;
+		def_ee.e_anongid = 65534;
+		def_ee.e_squids = NULL;
+		def_ee.e_sqgids = NULL;
+		def_ee.e_mountpoint = NULL;
+		def_ee.e_nsquids = 0;
+		def_ee.e_nsqgids = 0;
+
+		ok = getpath(def_ee.e_path, sizeof(def_ee.e_path));
 		if (ok <= 0)
 			return NULL;
-		strncpy (ee.m_path, ee.e_path, sizeof (ee.m_path) - 1);
-		ee.m_path [sizeof (ee.m_path) - 1] = '\0';
+
+		strncpy (def_ee.m_path, def_ee.e_path, sizeof (def_ee.m_path) - 1);
+		def_ee.m_path [sizeof (def_ee.m_path) - 1] = '\0';
 		ok = getexport(exp, sizeof(exp));
 	}
 	if (ok < 0) {
@@ -111,6 +117,23 @@ getexportent(int fromkernel, int fromexports)
 		return NULL;
 	}
 	first = 0;
+		
+	/* Check for default options */
+	if (exp[0] == '-') {
+		if (parseopts(exp + 1, &def_ee, 0, &has_default_subtree_opts) < 0)
+			return NULL;
+		
+		has_default_opts = 1;
+
+		ok = getexport(exp, sizeof(exp));
+		if (ok < 0) {
+			xlog(L_ERROR, "expected client(options...)");
+			export_errno = EINVAL;
+			return NULL;
+		}
+	}
+
+	ee = def_ee;
 
 	/* Check for default client */
 	if (ok == 0)
@@ -130,7 +153,8 @@ getexportent(int fromkernel, int fromexports)
 		}
 		*sp = '\0';
 	} else {
-	    xlog(L_WARNING, "No options for %s %s: suggest %s(sync) to avoid warning", ee.e_path, exp, exp);
+		if (!has_default_opts)
+			xlog(L_WARNING, "No options for %s %s: suggest %s(sync) to avoid warning", ee.e_path, exp, exp);
 	}
 	if (strlen(hostname) >= sizeof(ee.e_hostname)) {
 		syntaxerr("client name too long");
@@ -140,7 +164,7 @@ getexportent(int fromkernel, int fromexports)
 	strncpy(ee.e_hostname, hostname, sizeof (ee.e_hostname) - 1);
 	ee.e_hostname[sizeof (ee.e_hostname) - 1] = '\0';
 
-	if (parseopts(opt, &ee, fromexports) < 0)
+	if (parseopts(opt, &ee, fromexports && !has_default_subtree_opts, NULL) < 0)
 		return NULL;
 
 	/* resolve symlinks */
@@ -293,7 +317,7 @@ mkexportent(char *hname, char *path, char *options)
 	ee.e_path[sizeof (ee.e_path) - 1] = '\0';
 	strncpy (ee.m_path, ee.e_path, sizeof (ee.m_path) - 1);
 	ee.m_path [sizeof (ee.m_path) - 1] = '\0';
-	if (parseopts(options, &ee, 0) < 0)
+	if (parseopts(options, &ee, 0, NULL) < 0)
 		return NULL;
 	return &ee;
 }
@@ -301,7 +325,7 @@ mkexportent(char *hname, char *path, char *options)
 int
 updateexportent(struct exportent *eep, char *options)
 {
-	if (parseopts(options, eep, 0) < 0)
+	if (parseopts(options, eep, 0, NULL) < 0)
 		return 0;
 	return 1;
 }
@@ -310,7 +334,7 @@ updateexportent(struct exportent *eep, char *options)
  * Parse option string pointed to by cp and set mount options accordingly.
  */
 static int
-parseopts(char *cp, struct exportent *ep, int warn)
+parseopts(char *cp, struct exportent *ep, int warn, int *had_subtree_opt_ptr)
 {
 	int	had_subtree_opt = 0;
 	char 	*flname = efname?efname:"command line";
@@ -461,6 +485,8 @@ out:
 
 				flname, flline,
 				ep->e_hostname, ep->e_path);
+	if (had_subtree_opt_ptr)
+		*had_subtree_opt_ptr = had_subtree_opt;
 
 	return 1;
 }