Implement lxc.rootfs.options

This introduces a new lxc.rootfs.options which lets you pass new
mountflags/mountdata when mounting the root filesystem.

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

diff --git a/doc/lxc.container.conf.sgml.in b/doc/lxc.container.conf.sgml.in
index aee5451e832a5f07c1f3eb25379b3eee27f6b08b..5313b972a2aafa9505ed53849345ed73babd9c35 100644 (file)
--- a/doc/lxc.container.conf.sgml.in
+++ b/doc/lxc.container.conf.sgml.in
@@ -862,6 +862,17 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
          </listitem>
        </varlistentry>
 
+       <varlistentry>
+         <term>
+           <option>lxc.rootfs.options</option>
+         </term>
+         <listitem>
+           <para>
+             extra mount options to use when mounting the rootfs.
+           </para>
+         </listitem>
+       </varlistentry>
+
        <varlistentry>
          <term>
            <option>lxc.pivotdir</option>

diff --git a/src/lxc/bdev.c b/src/lxc/bdev.c
index c4e51214ca2c3815aadb6b1eb7cc248e4da9c928..39e677fa8039bedd23c7866dc38716d262be61aa 100644 (file)
--- a/src/lxc/bdev.c
+++ b/src/lxc/bdev.c
@@ -121,9 +121,11 @@ static int find_fstype_cb(char* buffer, void *data)
        struct cbarg {
                const char *rootfs;
                const char *target;
-               int mntopt;
+               const char *options;
        } *cbarg = data;
 
+       unsigned long mntflags;
+       char *mntdata;
        char *fstype;
 
        /* we don't try 'nodev' entries */
@@ -137,29 +139,38 @@ static int find_fstype_cb(char* buffer, void *data)
        DEBUG("trying to mount '%s'->'%s' with fstype '%s'",
              cbarg->rootfs, cbarg->target, fstype);
 
-       if (mount(cbarg->rootfs, cbarg->target, fstype, cbarg->mntopt, NULL)) {
+       if (parse_mntopts(cbarg->options, &mntflags, &mntdata) < 0) {
+               free(mntdata);
+               return 0;
+       }
+
+       if (mount(cbarg->rootfs, cbarg->target, fstype, mntflags, mntdata)) {
                DEBUG("mount failed with error: %s", strerror(errno));
+               free(mntdata);
                return 0;
        }
 
+       free(mntdata);
+
        INFO("mounted '%s' on '%s', with fstype '%s'",
             cbarg->rootfs, cbarg->target, fstype);
 
        return 1;
 }
 
-static int mount_unknown_fs(const char *rootfs, const char *target, int mntopt)
+static int mount_unknown_fs(const char *rootfs, const char *target,
+                                       const char *options)
 {
        int i;
 
        struct cbarg {
                const char *rootfs;
                const char *target;
-               int mntopt;
+               const char *options;
        } cbarg = {
                .rootfs = rootfs,
                .target = target,
-               .mntopt = mntopt,
+               .options = options,
        };
 
        /*
@@ -291,7 +302,7 @@ static int detect_fs(struct bdev *bdev, char *type, int len)
        if (unshare(CLONE_NEWNS) < 0)
                exit(1);
 
-       ret = mount_unknown_fs(srcdev, bdev->dest, 0);
+       ret = mount_unknown_fs(srcdev, bdev->dest, bdev->mntopts);
        if (ret < 0) {
                ERROR("failed mounting %s onto %s to detect fstype", srcdev, bdev->dest);
                exit(1);
@@ -355,11 +366,23 @@ static int dir_detect(const char *path)
 //
 static int dir_mount(struct bdev *bdev)
 {
+       unsigned long mntflags;
+       char *mntdata;
+       int ret;
+
        if (strcmp(bdev->type, "dir"))
                return -22;
        if (!bdev->src || !bdev->dest)
                return -22;
-       return mount(bdev->src, bdev->dest, "bind", MS_BIND | MS_REC, NULL);
+
+       if (parse_mntopts(bdev->mntopts, &mntflags, &mntdata) < 0) {
+               free(mntdata);
+               return -22;
+       }
+
+       ret = mount(bdev->src, bdev->dest, "bind", MS_BIND | MS_REC | mntflags, mntdata);
+       free(mntdata);
+       return ret;
 }
 
 static int dir_umount(struct bdev *bdev)
@@ -532,11 +555,23 @@ static int zfs_detect(const char *path)
 
 static int zfs_mount(struct bdev *bdev)
 {
+       unsigned long mntflags;
+       char *mntdata;
+       int ret;
+
        if (strcmp(bdev->type, "zfs"))
                return -22;
        if (!bdev->src || !bdev->dest)
                return -22;
-       return mount(bdev->src, bdev->dest, "bind", MS_BIND | MS_REC, NULL);
+
+       if (parse_mntopts(bdev->mntopts, &mntflags, &mntdata) < 0) {
+               free(mntdata);
+               return -22;
+       }
+
+       ret = mount(bdev->src, bdev->dest, "bind", MS_BIND | MS_REC | mntflags, mntdata);
+       free(mntdata);
+       return ret;
 }
 
 static int zfs_umount(struct bdev *bdev)
@@ -783,7 +818,7 @@ static int lvm_mount(struct bdev *bdev)
                return -22;
        /* if we might pass in data sometime, then we'll have to enrich
         * mount_unknown_fs */
-       return mount_unknown_fs(bdev->src, bdev->dest, 0);
+       return mount_unknown_fs(bdev->src, bdev->dest, bdev->mntopts);
 }
 
 static int lvm_umount(struct bdev *bdev)
@@ -996,9 +1031,9 @@ static int lvm_clonepaths(struct bdev *orig, struct bdev *new, const char *oldna
                        return -1;
        }
 
-       if (orig->data) {
-               new->data = strdup(orig->data);
-               if (!new->data)
+       if (orig->mntopts) {
+               new->mntopts = strdup(orig->mntopts);
+               if (!new->mntopts)
                        return -1;
        }
 
@@ -1191,11 +1226,23 @@ static int btrfs_detect(const char *path)
 
 static int btrfs_mount(struct bdev *bdev)
 {
+       unsigned long mntflags;
+       char *mntdata;
+       int ret;
+
        if (strcmp(bdev->type, "btrfs"))
                return -22;
        if (!bdev->src || !bdev->dest)
                return -22;
-       return mount(bdev->src, bdev->dest, "bind", MS_BIND | MS_REC, NULL);
+
+       if (parse_mntopts(bdev->mntopts, &mntflags, &mntdata) < 0) {
+               free(mntdata);
+               return -22;
+       }
+
+       ret = mount(bdev->src, bdev->dest, "bind", MS_BIND | MS_REC | mntflags, mntdata);
+       free(mntdata);
+       return ret;
 }
 
 static int btrfs_umount(struct bdev *bdev)
@@ -1356,7 +1403,7 @@ static int btrfs_clonepaths(struct bdev *orig, struct bdev *new, const char *old
        if ((new->dest = strdup(new->src)) == NULL)
                return -1;
 
-       if (orig->data && (new->data = strdup(orig->data)) == NULL)
+       if (orig->mntopts && (new->mntopts = strdup(orig->mntopts)) == NULL)
                return -1;
 
        if (snap)
@@ -1508,7 +1555,7 @@ static int loop_mount(struct bdev *bdev)
                goto out;
        }
 
-       ret = mount_unknown_fs(loname, bdev->dest, 0);
+       ret = mount_unknown_fs(loname, bdev->dest, bdev->mntopts);
        if (ret < 0)
                ERROR("Error mounting %s\n", bdev->src);
        else
@@ -1717,6 +1764,8 @@ static int overlayfs_mount(struct bdev *bdev)
 {
        char *options, *dup, *lower, *upper;
        int len;
+       unsigned long mntflags;
+       char *mntdata;
        int ret;
 
        if (strcmp(bdev->type, "overlayfs"))
@@ -1735,15 +1784,30 @@ static int overlayfs_mount(struct bdev *bdev)
        *upper = '\0';
        upper++;
 
+       if (parse_mntopts(bdev->mntopts, &mntflags, &mntdata) < 0) {
+               free(mntdata);
+               return -22;
+       }
+
        // TODO We should check whether bdev->src is a blockdev, and if so
        // but for now, only support overlays of a basic directory
 
-       len = strlen(lower) + strlen(upper) + strlen("upperdir=,lowerdir=") + 1;
-       options = alloca(len);
-       ret = snprintf(options, len, "upperdir=%s,lowerdir=%s", upper, lower);
-       if (ret < 0 || ret >= len)
+       if (mntdata) {
+               len = strlen(lower) + strlen(upper) + strlen("upperdir=,lowerdir=,") + strlen(mntdata) + 1;
+               options = alloca(len);
+               ret = snprintf(options, len, "upperdir=%s,lowerdir=%s,%s", upper, lower, mntdata);
+       }
+       else {
+               len = strlen(lower) + strlen(upper) + strlen("upperdir=,lowerdir=") + 1;
+               options = alloca(len);
+               ret = snprintf(options, len, "upperdir=%s,lowerdir=%s", upper, lower);
+       }
+       if (ret < 0 || ret >= len) {
+               free(mntdata);
                return -1;
-       ret = mount(lower, bdev->dest, "overlayfs", MS_MGC_VAL, options);
+       }
+
+       ret = mount(lower, bdev->dest, "overlayfs", MS_MGC_VAL | mntflags, options);
        if (ret < 0)
                SYSERROR("overlayfs: error mounting %s onto %s options %s",
                        lower, bdev->dest, options);
@@ -1946,8 +2010,8 @@ static const size_t numbdevs = sizeof(bdevs) / sizeof(struct bdev_type);
 
 void bdev_put(struct bdev *bdev)
 {
-       if (bdev->data)
-               free(bdev->data);
+       if (bdev->mntopts)
+               free(bdev->mntopts);
        if (bdev->src)
                free(bdev->src);
        if (bdev->dest)
@@ -1975,7 +2039,7 @@ struct bdev *bdev_get(const char *type)
        return bdev;
 }
 
-struct bdev *bdev_init(const char *src, const char *dst, const char *data)
+struct bdev *bdev_init(const char *src, const char *dst, const char *mntopts)
 {
        int i;
        struct bdev *bdev;
@@ -1995,8 +2059,8 @@ struct bdev *bdev_init(const char *src, const char *dst, const char *data)
        memset(bdev, 0, sizeof(struct bdev));
        bdev->ops = bdevs[i].ops;
        bdev->type = bdevs[i].name;
-       if (data)
-               bdev->data = strdup(data);
+       if (mntopts)
+               bdev->mntopts = strdup(mntopts);
        if (src)
                bdev->src = strdup(src);
        if (dst)

diff --git a/src/lxc/bdev.h b/src/lxc/bdev.h
index cc7b59e847ba1b91ebbd1f37bea2eb5b16f63a51..f2d6dc08d16cc61333cd6d3122842ad124f26b4d 100644 (file)
--- a/src/lxc/bdev.h
+++ b/src/lxc/bdev.h
@@ -78,7 +78,7 @@ struct bdev {
        const char *type;
        char *src;
        char *dest;
-       char *data;
+       char *mntopts;
        // turn the following into a union if need be
        // lofd is the open fd for the mounted loopback file
        int lofd;

diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index 8b790a2fcfe4ce78831cc99a0034d5619f1c0007..d4578f349e4a49dd71f30010457bdf2eb5ae077a 100644 (file)
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -424,9 +424,11 @@ static int find_fstype_cb(char* buffer, void *data)
        struct cbarg {
                const char *rootfs;
                const char *target;
-               int mntopt;
+               const char *options;
        } *cbarg = data;
 
+       unsigned long mntflags;
+       char *mntdata;
        char *fstype;
 
        /* we don't try 'nodev' entries */
@@ -440,10 +442,17 @@ static int find_fstype_cb(char* buffer, void *data)
        DEBUG("trying to mount '%s'->'%s' with fstype '%s'",
              cbarg->rootfs, cbarg->target, fstype);
 
-       if (mount(cbarg->rootfs, cbarg->target, fstype, cbarg->mntopt, NULL)) {
+       if (parse_mntopts(cbarg->options, &mntflags, &mntdata) < 0) {
+               free(mntdata);
+               return -1;
+       }
+
+       if (mount(cbarg->rootfs, cbarg->target, fstype, mntflags, mntdata)) {
                DEBUG("mount failed with error: %s", strerror(errno));
+               free(mntdata);
                return 0;
        }
+       free(mntdata);
 
        INFO("mounted '%s' on '%s', with fstype '%s'",
             cbarg->rootfs, cbarg->target, fstype);
@@ -451,18 +460,19 @@ static int find_fstype_cb(char* buffer, void *data)
        return 1;
 }
 
-static int mount_unknown_fs(const char *rootfs, const char *target, int mntopt)
+static int mount_unknown_fs(const char *rootfs, const char *target,
+                                       const char *options)
 {
        int i;
 
        struct cbarg {
                const char *rootfs;
                const char *target;
-               int mntopt;
+               const char *options;
        } cbarg = {
                .rootfs = rootfs,
                .target = target,
-               .mntopt = mntopt,
+               .options = options,
        };
 
        /*
@@ -496,9 +506,22 @@ static int mount_unknown_fs(const char *rootfs, const char *target, int mntopt)
        return -1;
 }
 
-static int mount_rootfs_dir(const char *rootfs, const char *target)
+static int mount_rootfs_dir(const char *rootfs, const char *target,
+                                       const char *options)
 {
-       return mount(rootfs, target, "none", MS_BIND | MS_REC, NULL);
+       unsigned long mntflags;
+       char *mntdata;
+       int ret;
+
+       if (parse_mntopts(options, &mntflags, &mntdata) < 0) {
+               free(mntdata);
+               return -1;
+       }
+
+       ret = mount(rootfs, target, "none", MS_BIND | MS_REC | mntflags, mntdata);
+       free(mntdata);
+
+       return ret;
 }
 
 static int setup_lodev(const char *rootfs, int fd, struct loop_info64 *loinfo)
@@ -533,7 +556,8 @@ out:
        return ret;
 }
 
-static int mount_rootfs_file(const char *rootfs, const char *target)
+static int mount_rootfs_file(const char *rootfs, const char *target,
+                                            const char *options)
 {
        struct dirent dirent, *direntp;
        struct loop_info64 loinfo;
@@ -585,7 +609,7 @@ static int mount_rootfs_file(const char *rootfs, const char *target)
 
                ret = setup_lodev(rootfs, fd, &loinfo);
                if (!ret)
-                       ret = mount_unknown_fs(path, target, 0);
+                       ret = mount_unknown_fs(path, target, options);
                close(fd);
 
                break;
@@ -597,9 +621,10 @@ static int mount_rootfs_file(const char *rootfs, const char *target)
        return ret;
 }
 
-static int mount_rootfs_block(const char *rootfs, const char *target)
+static int mount_rootfs_block(const char *rootfs, const char *target,
+                                         const char *options)
 {
-       return mount_unknown_fs(rootfs, target, 0);
+       return mount_unknown_fs(rootfs, target, options);
 }
 
 /*
@@ -729,13 +754,13 @@ static int lxc_mount_auto_mounts(struct lxc_conf *conf, int flags, struct lxc_cg
        return 0;
 }
 
-static int mount_rootfs(const char *rootfs, const char *target)
+static int mount_rootfs(const char *rootfs, const char *target, const char *options)
 {
        char absrootfs[MAXPATHLEN];
        struct stat s;
        int i;
 
-       typedef int (*rootfs_cb)(const char *, const char *);
+       typedef int (*rootfs_cb)(const char *, const char *, const char *);
 
        struct rootfs_type {
                int type;
@@ -766,7 +791,7 @@ static int mount_rootfs(const char *rootfs, const char *target)
                if (!__S_ISTYPE(s.st_mode, rtfs_type[i].type))
                        continue;
 
-               return rtfs_type[i].cb(absrootfs, target);
+               return rtfs_type[i].cb(absrootfs, target, options);
        }
 
        ERROR("unsupported rootfs type for '%s'", absrootfs);
@@ -1530,7 +1555,7 @@ static int setup_rootfs(struct lxc_conf *conf)
        }
 
        // First try mounting rootfs using a bdev
-       struct bdev *bdev = bdev_init(rootfs->path, rootfs->mount, NULL);
+       struct bdev *bdev = bdev_init(rootfs->path, rootfs->mount, rootfs->options);
        if (bdev && bdev->ops->mount(bdev) == 0) {
                bdev_put(bdev);
                DEBUG("mounted '%s' on '%s'", rootfs->path, rootfs->mount);
@@ -1538,7 +1563,7 @@ static int setup_rootfs(struct lxc_conf *conf)
        }
        if (bdev)
                bdev_put(bdev);
-       if (mount_rootfs(rootfs->path, rootfs->mount)) {
+       if (mount_rootfs(rootfs->path, rootfs->mount, rootfs->options)) {
                ERROR("failed to mount rootfs");
                return -1;
        }
@@ -1791,7 +1816,7 @@ static void parse_mntopt(char *opt, unsigned long *flags, char **data)
        strcat(*data, opt);
 }
 
-static int parse_mntopts(const char *mntopts, unsigned long *mntflags,
+int parse_mntopts(const char *mntopts, unsigned long *mntflags,
                         char **mntdata)
 {
        char *s, *data;
@@ -1865,11 +1890,6 @@ static inline int mount_entry_on_systemfs(const struct mntent *mntent)
        FILE *pathfile = NULL;
        char* pathdirname = NULL;
 
-       if (parse_mntopts(mntent->mnt_opts, &mntflags, &mntdata) < 0) {
-               ERROR("failed to parse mount option '%s'", mntent->mnt_opts);
-               return -1;
-       }
-
        if (hasmntopt(mntent, "create=dir")) {
                if (!mkdir_p(mntent->mnt_dir, 0755)) {
                        WARN("Failed to create mount target '%s'", mntent->mnt_dir);
@@ -1890,6 +1910,11 @@ static inline int mount_entry_on_systemfs(const struct mntent *mntent)
                        fclose(pathfile);
        }
 
+       if (parse_mntopts(mntent->mnt_opts, &mntflags, &mntdata) < 0) {
+               free(mntdata);
+               return -1;
+       }
+
        ret = mount_entry(mntent->mnt_fsname, mntent->mnt_dir,
                          mntent->mnt_type, mntflags, mntdata);
 
@@ -1915,11 +1940,6 @@ static int mount_entry_on_absolute_rootfs(const struct mntent *mntent,
        FILE *pathfile = NULL;
        char *pathdirname = NULL;
 
-       if (parse_mntopts(mntent->mnt_opts, &mntflags, &mntdata) < 0) {
-               ERROR("failed to parse mount option '%s'", mntent->mnt_opts);
-               return -1;
-       }
-
        lxcpath = lxc_global_config_value("lxc.lxcpath");
        if (!lxcpath) {
                ERROR("Out of memory");
@@ -1976,15 +1996,21 @@ skipabs:
                        fclose(pathfile);
        }
 
+       if (parse_mntopts(mntent->mnt_opts, &mntflags, &mntdata) < 0) {
+               free(mntdata);
+               return -1;
+       }
+
        ret = mount_entry(mntent->mnt_fsname, path, mntent->mnt_type,
                          mntflags, mntdata);
 
+       free(mntdata);
+
        if (hasmntopt(mntent, "optional") != NULL)
                ret = 0;
 
 out:
        free(pathdirname);
-       free(mntdata);
        return ret;
 }
 
@@ -1998,11 +2024,6 @@ static int mount_entry_on_relative_rootfs(const struct mntent *mntent,
        FILE *pathfile = NULL;
        char *pathdirname = NULL;
 
-       if (parse_mntopts(mntent->mnt_opts, &mntflags, &mntdata) < 0) {
-               ERROR("failed to parse mount option '%s'", mntent->mnt_opts);
-               return -1;
-       }
-
        /* relative to root mount point */
        ret = snprintf(path, sizeof(path), "%s/%s", rootfs, mntent->mnt_dir);
        if (ret >= sizeof(path)) {
@@ -2030,6 +2051,11 @@ static int mount_entry_on_relative_rootfs(const struct mntent *mntent,
                        fclose(pathfile);
        }
 
+       if (parse_mntopts(mntent->mnt_opts, &mntflags, &mntdata) < 0) {
+               free(mntdata);
+               return -1;
+       }
+
        ret = mount_entry(mntent->mnt_fsname, path, mntent->mnt_type,
                          mntflags, mntdata);
 
@@ -3906,6 +3932,8 @@ void lxc_conf_free(struct lxc_conf *conf)
                free(conf->console.path);
        if (conf->rootfs.mount)
                free(conf->rootfs.mount);
+       if (conf->rootfs.options)
+               free(conf->rootfs.options);
        if (conf->rootfs.path)
                free(conf->rootfs.path);
        if (conf->rootfs.pivot)

diff --git a/src/lxc/conf.h b/src/lxc/conf.h
index cd4b115bd1bffb42c5a7c71380c71a5efeb113d4..e5a23ec44d3d23b7267fde5df824b7562363f814 100644 (file)
--- a/src/lxc/conf.h
+++ b/src/lxc/conf.h
@@ -219,6 +219,7 @@ struct lxc_rootfs {
        char *path;
        char *mount;
        char *pivot;
+       char *options;
 };
 
 /*
@@ -375,4 +376,6 @@ extern int mapped_hostid(int id, struct lxc_conf *conf);
 extern int chown_mapped_root(char *path, struct lxc_conf *conf);
 extern int ttys_shift_ids(struct lxc_conf *c);
 extern int userns_exec_1(struct lxc_conf *conf, int (*fn)(void *), void *data);
+extern int parse_mntopts(const char *mntopts, unsigned long *mntflags,
+                        char **mntdata);
 #endif

diff --git a/src/lxc/confile.c b/src/lxc/confile.c
index 8a027cc30307418372ea74f847e8bc4e9d8b1ed5..03a42c5b37215ff927a7491c19ba992c51c0ab4a 100644 (file)
--- a/src/lxc/confile.c
+++ b/src/lxc/confile.c
@@ -65,6 +65,7 @@ static int config_logfile(const char *, const char *, struct lxc_conf *);
 static int config_mount(const char *, const char *, struct lxc_conf *);
 static int config_rootfs(const char *, const char *, struct lxc_conf *);
 static int config_rootfs_mount(const char *, const char *, struct lxc_conf *);
+static int config_rootfs_options(const char *, const char *, struct lxc_conf *);
 static int config_pivotdir(const char *, const char *, struct lxc_conf *);
 static int config_utsname(const char *, const char *, struct lxc_conf *);
 static int config_hook(const char *, const char *, struct lxc_conf *lxc_conf);
@@ -110,6 +111,7 @@ static struct lxc_config_t config[] = {
        { "lxc.logfile",              config_logfile              },
        { "lxc.mount",                config_mount                },
        { "lxc.rootfs.mount",         config_rootfs_mount         },
+       { "lxc.rootfs.options",       config_rootfs_options       },
        { "lxc.rootfs",               config_rootfs               },
        { "lxc.pivotdir",             config_pivotdir             },
        { "lxc.utsname",              config_utsname              },
@@ -1566,6 +1568,12 @@ static int config_rootfs_mount(const char *key, const char *value,
        return config_path_item(&lxc_conf->rootfs.mount, value);
 }
 
+static int config_rootfs_options(const char *key, const char *value,
+                              struct lxc_conf *lxc_conf)
+{
+       return config_string_item(&lxc_conf->rootfs.options, value);
+}
+
 static int config_pivotdir(const char *key, const char *value,
                           struct lxc_conf *lxc_conf)
 {
@@ -2096,6 +2104,8 @@ int lxc_get_config_item(struct lxc_conf *c, const char *key, char *retv,
                v = c->console.path;
        else if (strcmp(key, "lxc.rootfs.mount") == 0)
                v = c->rootfs.mount;
+       else if (strcmp(key, "lxc.rootfs.options") == 0)
+               v = c->rootfs.options;
        else if (strcmp(key, "lxc.rootfs") == 0)
                v = c->rootfs.path;
        else if (strcmp(key, "lxc.pivotdir") == 0)
@@ -2313,6 +2323,8 @@ void write_config(FILE *fout, struct lxc_conf *c)
                fprintf(fout, "lxc.rootfs = %s\n", c->rootfs.path);
        if (c->rootfs.mount && strcmp(c->rootfs.mount, LXCROOTFSMOUNT) != 0)
                fprintf(fout, "lxc.rootfs.mount = %s\n", c->rootfs.mount);
+       if (c->rootfs.options)
+               fprintf(fout, "lxc.rootfs.options = %s\n", c->rootfs.options);
        if (c->rootfs.pivot)
                fprintf(fout, "lxc.pivotdir = %s\n", c->rootfs.pivot);
        if (c->start_auto)