[RFC PATCH 5/5] Add support for chroot in exportfs

[Trond Myklebust <trondmy@xxxxxxxxx>]

Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
---
 utils/exportfs/Makefile.am |  2 +-
 utils/exportfs/exportfs.c  | 31 ++++++++++++++++++++++++++++++-
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/utils/exportfs/Makefile.am b/utils/exportfs/Makefile.am
index 4b291610d19b..96524c729359 100644
--- a/utils/exportfs/Makefile.am
+++ b/utils/exportfs/Makefile.am
@@ -10,6 +10,6 @@ exportfs_SOURCES = exportfs.c
 exportfs_LDADD = ../../support/export/libexport.a \
 	       	 ../../support/nfs/libnfs.la \
 		 ../../support/misc/libmisc.a \
-		 $(LIBWRAP) $(LIBNSL)
+		 $(LIBWRAP) $(LIBNSL) $(LIBPTHREAD)
 
 MAINTAINERCLEANFILES = Makefile.in
diff --git a/utils/exportfs/exportfs.c b/utils/exportfs/exportfs.c
index 333eadcd0228..bc87d7fe4ee1 100644
--- a/utils/exportfs/exportfs.c
+++ b/utils/exportfs/exportfs.c
@@ -52,6 +52,33 @@ static const char *lockfile = EXP_LOCKFILE;
 static int _lockfd = -1;
 
 struct state_paths etab;
+static struct xthread_workqueue *exportfs_wq;
+
+static ssize_t exportfs_write(int fd, const char *buf, size_t len)
+{
+	if (exportfs_wq)
+		return xthread_write(exportfs_wq, fd, buf, len);
+	return write(fd, buf, len);
+}
+
+static void
+exportfs_setup_workqueue(void)
+{
+	const char *chroot;
+
+	chroot = conf_get_str("nfsd", "chroot");
+	if (!chroot || *chroot == '\0')
+		return;
+	/* Strip leading '/' */
+	while (chroot[0] == '/' && chroot[1] == '/')
+		chroot++;
+	if (chroot[0] == '/' && chroot[1] == '\0')
+		return;
+	exportfs_wq = xthread_workqueue_alloc();
+	if (!exportfs_wq)
+		return;
+	xthread_workqueue_chroot(exportfs_wq, chroot);
+}
 
 /*
  * If we aren't careful, changes made by exportfs can be lost
@@ -181,6 +208,8 @@ main(int argc, char **argv)
 		}
 	}
 
+	exportfs_setup_workqueue();
+
 	/*
 	 * Serialize things as best we can
 	 */
@@ -505,7 +534,7 @@ static int test_export(nfs_export *exp, int with_fsid)
 	fd = open("/proc/net/rpc/nfsd.export/channel", O_WRONLY);
 	if (fd < 0)
 		return 0;
-	n = write(fd, buf, strlen(buf));
+	n = exportfs_write(fd, buf, strlen(buf));
 	close(fd);
 	if (n < 0)
 		return 0;
-- 
2.21.0