[PATCH 4/5] export: Avoid fsid= conflicts

[Richard Weinberger <richard@nod.at>]

As soon reexport= is used, numerical fsids are automatically
assigned, therefore other fsid= options are no longer possible
without the risk of a conflict.

Signed-off-by: Richard Weinberger <richard@nod.at>
---
 support/export/export.c        | 27 +++++++++++++++++++++++++--
 systemd/nfs-server-generator.c | 14 ++++++++++++--
 utils/exportfs/exportfs.c      | 10 ++++++++--
 3 files changed, 45 insertions(+), 6 deletions(-)

diff --git a/support/export/export.c b/support/export/export.c
index 03390dfc..c5e56b1a 100644
--- a/support/export/export.c
+++ b/support/export/export.c
@@ -25,6 +25,7 @@
 #include "exportfs.h"
 #include "nfsd_path.h"
 #include "xlog.h"
+#include "reexport.h"
 
 exp_hash_table exportlist[MCL_MAXTYPES] = {{NULL, {{NULL,NULL}, }}, }; 
 static int export_hash(char *);
@@ -115,6 +116,7 @@ export_read(char *fname, int ignore_hosts)
 	nfs_export		*exp;
 
 	int volumes = 0;
+	int reexport_found = 0;
 
 	setexportent(fname, "r");
 	while ((eep = getexportent(0,1)) != NULL) {
@@ -126,7 +128,25 @@ export_read(char *fname, int ignore_hosts)
 		}
 		else
 			warn_duplicated_exports(exp, eep);
+
+		if (eep->e_reexport)
+			reexport_found = 1;
+	}
+
+	if (reexport_found) {
+		for (int i = 0; i < MCL_MAXTYPES; i++) {
+			for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {
+				if (exp->m_export.e_reexport)
+					continue;
+
+				if (exp->m_export.e_flags & NFSEXP_FSID) {
+					xlog(L_ERROR, "When a reexport= option is present no manully assigned numerical fsid= options are allowed");
+					return -1;
+				}
+			}
+		}
 	}
+
 	endexportent();
 
 	return volumes;
@@ -147,7 +167,7 @@ export_d_read(const char *dname, int ignore_hosts)
 	int n = 0, i;
 	struct dirent **namelist = NULL;
 	int volumes = 0;
-
+	int num_exports;
 
 	n = scandir(dname, &namelist, NULL, versionsort);
 	if (n < 0) {
@@ -186,7 +206,10 @@ export_d_read(const char *dname, int ignore_hosts)
 			continue;
 		}
 
-		volumes += export_read(fname, ignore_hosts);
+		num_exports = export_read(fname, ignore_hosts);
+		if (num_exports < 0)
+			return -1;
+		volumes += num_exports;
 	}
 
 	for (i = 0; i < n; i++)
diff --git a/systemd/nfs-server-generator.c b/systemd/nfs-server-generator.c
index eec98fd2..e4202954 100644
--- a/systemd/nfs-server-generator.c
+++ b/systemd/nfs-server-generator.c
@@ -89,6 +89,8 @@ int main(int argc, char *argv[])
 	struct list	*list = NULL;
 	FILE		*f, *fstab;
 	struct mntent	*mnt;
+	int		num_exports;
+	int		num_exports_d;
 
 	/* Avoid using any external services */
 	xlog_syslog(0);
@@ -102,8 +104,16 @@ int main(int argc, char *argv[])
 	path = alloca(strlen(argv[1]) + sizeof(dirbase) + sizeof(filebase));
 	if (!path)
 		exit(2);
-	if (export_read(_PATH_EXPORTS, 1) +
-	    export_d_read(_PATH_EXPORTS_D, 1) == 0)
+
+	num_exports = export_read(_PATH_EXPORTS, 1);
+	if (num_exports < 0)
+		exit(1);
+
+	num_exports_d = export_d_read(_PATH_EXPORTS_D, 1);
+	if (num_exports_d < 0)
+		exit(1);
+
+	if (num_exports + num_exports_d == 0)
 		/* Nothing is exported, so nothing to do */
 		exit(0);
 
diff --git a/utils/exportfs/exportfs.c b/utils/exportfs/exportfs.c
index 7f21edcf..7a67c4d3 100644
--- a/utils/exportfs/exportfs.c
+++ b/utils/exportfs/exportfs.c
@@ -206,8 +206,14 @@ main(int argc, char **argv)
 	atexit(release_lockfile);
 
 	if (f_export && ! f_ignore) {
-		if (! (export_read(_PATH_EXPORTS, 0) +
-		       export_d_read(_PATH_EXPORTS_D, 0))) {
+		int num_exports, num_exports_d;
+
+		num_exports = export_read(_PATH_EXPORTS, 0);
+		num_exports_d = export_d_read(_PATH_EXPORTS_D, 0);
+		if (num_exports < 0 || num_exports_d < 0)
+			return 1;
+
+		if (!(num_exports + num_exports_d)) {
 			if (f_verbose)
 				xlog(L_WARNING, "No file systems exported!");
 		}
-- 
2.31.1