[lxc-devel] [PATCH 1/1] drop create= from mount options

[Serge Hallyn]

Otherwise mount may return -EINVAL if in-kernel super-block parser
objects (as is the case with ext4).

We may want to specifically look for create=file and create=dir, in case
create=sniggly becomes a real mount option for some fs...

Signed-off-by: Serge Hallyn <serge.hallyn at ubuntu.com>
---
 src/lxc/conf.c | 28 +++++++++++++++++++++++++---
 1 file changed, 25 insertions(+), 3 deletions(-)

diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index d40e3e0..c93403a 100644
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -1881,7 +1881,25 @@ static int mount_entry(const char *fsname, const char *target,
 	return 0;
 }
 
-static inline int mount_entry_on_systemfs(const struct mntent *mntent)
+/*
+ * Remove 'create=dir' or 'create=file' from mntopt
+ */
+static void cull_mntent_opt(struct mntent *mntent)
+{
+	char *p, *p2;
+
+	while ((p = strstr(mntent->mnt_opts, "create="))) {
+		p2 = strchr(p, ',');
+		if (!p2) {
+			/* no more mntopts, so just chop it here */
+			*p = '\0';
+			return;
+		}
+		memmove(p2+1, p, strlen(p2+1)+1);
+	}
+}
+
+static inline int mount_entry_on_systemfs(struct mntent *mntent)
 {
 	unsigned long mntflags;
 	char *mntdata;
@@ -1911,6 +1929,8 @@ static inline int mount_entry_on_systemfs(const struct mntent *mntent)
 			fclose(pathfile);
 	}
 
+	cull_mntent_opt(mntent);
+
 	if (parse_mntopts(mntent->mnt_opts, &mntflags, &mntdata) < 0) {
 		free(mntdata);
 		return -1;
@@ -1928,7 +1948,7 @@ static inline int mount_entry_on_systemfs(const struct mntent *mntent)
 	return ret;
 }
 
-static int mount_entry_on_absolute_rootfs(const struct mntent *mntent,
+static int mount_entry_on_absolute_rootfs(struct mntent *mntent,
 					  const struct lxc_rootfs *rootfs,
 					  const char *lxc_name)
 {
@@ -1998,6 +2018,7 @@ skipabs:
 		else
 			fclose(pathfile);
 	}
+	cull_mntent_opt(mntent);
 
 	if (parse_mntopts(mntent->mnt_opts, &mntflags, &mntdata) < 0) {
 		free(mntdata);
@@ -2017,7 +2038,7 @@ out:
 	return ret;
 }
 
-static int mount_entry_on_relative_rootfs(const struct mntent *mntent,
+static int mount_entry_on_relative_rootfs(struct mntent *mntent,
 					  const char *rootfs)
 {
 	char path[MAXPATHLEN];
@@ -2055,6 +2076,7 @@ static int mount_entry_on_relative_rootfs(const struct mntent *mntent,
 		else
 			fclose(pathfile);
 	}
+	cull_mntent_opt(mntent);
 
 	if (parse_mntopts(mntent->mnt_opts, &mntflags, &mntdata) < 0) {
 		free(mntdata);
-- 
1.9.rc1