libmount: fix new API code when use external helper

We don't want to call fsopen() or so if external /sbin/mount.<type>
helper is expected.

This patch also add fallback to propagation hook to open mount tree
if necessary.

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/libmount/src/hook_mount.c b/libmount/src/hook_mount.c
index 6f7020fe2ad209a6196517c4de3befd0622c8bbb..fced20b41df7bf00338d6f6f66adb4fbefadfb1f 100644 (file)
--- a/libmount/src/hook_mount.c
+++ b/libmount/src/hook_mount.c
@@ -178,6 +178,38 @@ static int open_fs_configuration_context(struct libmnt_context *cxt, const char
        return fd;
 }
 
+static int open_mount_tree(struct libmnt_context *cxt, const char *path, unsigned long mflg)
+{
+       unsigned long oflg = OPEN_TREE_CLOEXEC;
+       int rc = 0, fd = -1;
+
+       if (mflg == (unsigned long) -1) {
+               rc = mnt_optlist_get_flags(cxt->optlist, &mflg, cxt->map_linux, 0);
+               if (rc)
+                       return rc;
+       }
+       if (!path) {
+               path = mnt_fs_get_target(cxt->fs);
+               if (!path)
+                       return -EINVAL;
+       }
+
+       /* Classic -oremount,bind,ro is not bind operation, it's just
+        * VFS flags update only */
+       if ((mflg & MS_BIND) && !(mflg & MS_REMOUNT)) {
+               oflg |= OPEN_TREE_CLONE;
+
+               if (mnt_optlist_is_rbind(cxt->optlist))
+                       oflg |= AT_RECURSIVE;
+       }
+
+       DBG(HOOK, ul_debug("open_tree(path=%s, flgs=0x%08lx)", path, oflg));
+       fd = open_tree(AT_FDCWD, path, oflg);
+       set_syscall_status(cxt, "open_tree", fd >= 0);
+
+       return fd;
+}
+
 static int hook_create_mount(struct libmnt_context *cxt,
                        const struct libmnt_hookset *hs,
                        void *data __attribute__((__unused__)))
@@ -284,13 +316,21 @@ static int hook_set_vfsflags(struct libmnt_context *cxt,
        struct mount_attr attr = { .attr_clr = 0 };
        unsigned int callflags = AT_EMPTY_PATH;
        uint64_t set = 0, clr = 0;
-       int rc;
+       int rc = 0;
 
        DBG(HOOK, ul_debugobj(hs, "setting VFS flags"));
 
        api = get_sysapi(cxt, hs);
        assert(api);
-       assert(api->fd_tree >= 0);
+
+       /* fallback only; necessary when init_sysapi() during preparation
+        * cannot open the tree -- for example when we call /sbin/mount.<type> */
+       if (api->fd_tree < 0 && mnt_fs_get_target(cxt->fs)) {
+               rc = api->fd_tree = open_mount_tree(cxt, NULL, (unsigned long) -1);
+               if (rc < 0)
+                       goto done;
+               rc = 0;
+       }
 
        ol = mnt_context_get_optlist(cxt);
        if (!ol)
@@ -313,7 +353,7 @@ static int hook_set_vfsflags(struct libmnt_context *cxt,
 
        rc = mount_setattr(api->fd_tree, "", callflags, &attr, sizeof(attr));
        set_syscall_status(cxt, "move_setattr", rc == 0);
-
+done:
        return rc == 0 ? 0 : -errno;
 }
 
@@ -335,7 +375,15 @@ static int hook_set_propagation(struct libmnt_context *cxt,
 
        api = get_sysapi(cxt, hs);
        assert(api);
-       assert(api->fd_tree >= 0);
+
+       /* fallback only; necessary when init_sysapi() during preparation
+        * cannot open the tree -- for example when we call /sbin/mount.<type> */
+       if (api->fd_tree < 0 && mnt_fs_get_target(cxt->fs)) {
+               rc = api->fd_tree = open_mount_tree(cxt, NULL, (unsigned long) -1);
+               if (rc < 0)
+                       goto done;
+               rc = 0;
+       }
 
        mnt_reset_iter(&itr, MNT_ITER_FORWARD);
 
@@ -363,10 +411,10 @@ static int hook_set_propagation(struct libmnt_context *cxt,
                rc = mount_setattr(api->fd_tree, "", flgs, &attr, sizeof(attr));
                set_syscall_status(cxt, "move_setattr", rc == 0);
                if (rc != 0)
-                       return rc;
+                       break;
        }
-
-       return 0;
+done:
+       return rc == 0 ? 0 : -errno;
 }
 
 static int hook_attach_target(struct libmnt_context *cxt,
@@ -375,7 +423,7 @@ static int hook_attach_target(struct libmnt_context *cxt,
 {
        struct libmnt_sysapi *api;
        const char *target;
-       int rc;
+       int rc = 0;
 
        target = mnt_fs_get_target(cxt->fs);
        if (!target)
@@ -385,11 +433,12 @@ static int hook_attach_target(struct libmnt_context *cxt,
        assert(api);
        assert(api->fd_tree >= 0);
 
-       DBG(HOOK, ul_debugobj(hs, "move_mount(to=%s)", target));
-
-       rc = move_mount(api->fd_tree, "", AT_FDCWD, target, MOVE_MOUNT_F_EMPTY_PATH);
-       set_syscall_status(cxt, "move_mount", rc == 0);
+       if (!rc) {
+               DBG(HOOK, ul_debugobj(hs, "move_mount(to=%s)", target));
 
+               rc = move_mount(api->fd_tree, "", AT_FDCWD, target, MOVE_MOUNT_F_EMPTY_PATH);
+               set_syscall_status(cxt, "move_mount", rc == 0);
+       }
        return rc == 0 ? 0 : -errno;
 }
 
@@ -429,25 +478,12 @@ static int init_sysapi(struct libmnt_context *cxt,
        if (!api)
                return -ENOMEM;
 
-       if (path) {
-               unsigned long oflg = OPEN_TREE_CLOEXEC;
-
-               /* Classic -oremount,bind,ro is not bind operation, it's just
-                * VFS flags update only */
-               if ((flags & MS_BIND) && !(flags & MS_REMOUNT)) {
-                       oflg |= OPEN_TREE_CLONE;
-
-                       if (mnt_optlist_is_rbind(cxt->optlist))
-                               oflg |= AT_RECURSIVE;
-               }
-
-               DBG(HOOK, ul_debugobj(hs, "open_tree(path=%s, flgs=0x%08lx)", path, oflg));
-               if (mnt_context_is_fake(cxt))
-                       goto fake;
+       if (mnt_context_is_fake(cxt))
+               goto fake;
 
-               api->fd_tree = open_tree(AT_FDCWD, path, oflg);
-               set_syscall_status(cxt, "open_tree", api->fd_tree >= 0);
-               if (api->fd_tree <= 0)
+       if (path) {
+               api->fd_tree = open_mount_tree(cxt, path, flags);
+               if (api->fd_tree < 0)
                        goto fail;
 
        /* C) FS based operation
@@ -460,7 +496,7 @@ static int init_sysapi(struct libmnt_context *cxt,
 
                if (mnt_context_is_fake(cxt))
                        goto fake;
-               if (type && !strchr(type, ',')) {
+               if (cxt->helper == NULL && type && !strchr(type, ',')) {
                        api->fd_fs = open_fs_configuration_context(cxt, type);
                        if (api->fd_fs < 0)
                                goto fail;
@@ -519,12 +555,16 @@ static int hook_prepare(struct libmnt_context *cxt,
                return -EINVAL;
 
        /* classic remount (note -oremount,bind,ro is not superblock reconfiguration) */
-       if (!rc && (flags & MS_REMOUNT) && !(flags & MS_BIND))
+       if (!rc
+           && cxt->helper == NULL
+           && (flags & MS_REMOUNT)
+           && !(flags & MS_BIND))
                rc = mnt_context_append_hook(cxt, hs, MNT_STAGE_MOUNT, NULL,
                                        hook_reconfigure_mount);
 
        /* create a new FS instance */
        else if (!rc
+           && cxt->helper == NULL
            && !(flags & MS_BIND)
            && !(flags & MS_MOVE)
            && !(flags & MS_REMOUNT)
@@ -533,12 +573,15 @@ static int hook_prepare(struct libmnt_context *cxt,
                                        hook_create_mount);
 
        /* call mount_setattr() */
-       if (!rc && (set != 0 || clr != 0))
+       if (!rc
+           && cxt->helper == NULL
+           && (set != 0 || clr != 0))
                rc = mnt_context_append_hook(cxt, hs, MNT_STAGE_MOUNT, NULL,
                                        hook_set_vfsflags);
 
        /* call move_mount() to attach target */
        if (!rc
+           && cxt->helper == NULL
            && !(flags & MS_REMOUNT)
            && !mnt_context_propagation_only(cxt))
                rc = mnt_context_append_hook(cxt, hs, MNT_STAGE_MOUNT_POST, NULL,

diff --git a/libmount/src/hook_mount_legacy.c b/libmount/src/hook_mount_legacy.c
index 67ee68679891d9dd011c8069376b23542d9a3043..86069dd909c6fc5f8a1e2bfde7846af75721099a 100644 (file)
--- a/libmount/src/hook_mount_legacy.c
+++ b/libmount/src/hook_mount_legacy.c
@@ -287,8 +287,8 @@ static int hook_prepare(struct libmnt_context *cxt,
        if (mnt_context_has_hook(cxt, &hookset_mount, 0, NULL))
                return 0;
 #endif
-       /* append regual FS mount(2) */
-       if (!mnt_context_propagation_only(cxt))
+       /* append regular FS mount(2) */
+       if (!mnt_context_propagation_only(cxt) && !cxt->helper)
                rc = mnt_context_append_hook(cxt, hs,
                                MNT_STAGE_MOUNT, NULL, hook_mount);
 

diff --git a/tests/ts/mount/special b/tests/ts/mount/special
index ea2172564f2fbf45176a978c6045e39be8ce9060..088a1ac78400d57f047e7636fa81112fe4f36072 100755 (executable)
--- a/tests/ts/mount/special
+++ b/tests/ts/mount/special
@@ -36,7 +36,6 @@ EOF
 chmod +x $MOUNTER
 
 $TS_CMD_MOUNT -t mytest /foo /bar &> $TS_OUTPUT
-
 rm -f $MOUNTER
 
 ts_finalize