libmount: improve fstab/mtab options usage

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

diff --git a/shlibs/mount/src/context.c b/shlibs/mount/src/context.c
index 82a47a0eb80e7399e23b772e8fb7268feca0d612..13c5596f8e0d0ee954c1ff1036d0e7122735e273 100644 (file)
--- a/shlibs/mount/src/context.c
+++ b/shlibs/mount/src/context.c
@@ -189,21 +189,9 @@ int mnt_context_is_restricted(mnt_context *cxt)
 /**
  * mnt_context_set_optsmode
  * @cxt: mount context
- * @mode: MNT_OPTSMODE_{AUTO,FORCE,IGNORE,MTABFORCE}
+ * @mode: mask, see MNT_OMASK_* flags in libmount mount.h
  *
- * Defines a mode how libmount uses fstab mount options:
- *
- *  auto       - use options from fstab if source or target are not
- *               defined (this is mount(8) default).
- *
- *             - For remount operation it reads options from mtab if
- *               the target is not found in fstab.
- *
- *  ignore     - never use mount options from fstab
- *
- *  force      - always use mount options from fstab
- *
- *  mtab-force - for remount operation always use options from mtab (mountinfo)
+ * Controls how to use mount options from fstab/mtab.
  *
  * Returns: 0 on success, negative number in case of error.
  */
@@ -1189,17 +1177,6 @@ int mnt_context_update_tabs(mnt_context *cxt)
        return mnt_update_tab(cxt->update, mnt_context_get_lock(cxt));
 }
 
-static int is_remount(mnt_context *cxt)
-{
-       unsigned long fl = 0;
-
-       if (cxt->mountflags & MS_REMOUNT)
-               return 1;
-       if (!mnt_context_get_mountflags(cxt, &fl) && (fl & MS_REMOUNT))
-               return 1;
-       return 0;
-}
-
 static int apply_tab(mnt_context *cxt, mnt_tab *tb, int direction)
 {
        mnt_fs *fs = NULL;
@@ -1216,7 +1193,7 @@ static int apply_tab(mnt_context *cxt, mnt_tab *tb, int direction)
        tgt = mnt_fs_get_target(cxt->fs);
 
        if (tgt && src)
-               ;       /* TODO: search pair for MNT_OPTSMODE_FORCE */
+               fs = mnt_tab_find_pair(tb, src, tgt, direction);
        else {
                if (src)
                        fs = mnt_tab_find_source(tb, src, direction);
@@ -1245,7 +1222,7 @@ static int apply_tab(mnt_context *cxt, mnt_tab *tb, int direction)
        DBG(CXT, mnt_debug_h(cxt, "apply entry:"));
        DBG(CXT, mnt_fs_print_debug(fs, stderr));
 
-       /* copy from fstab to our FS description
+       /* copy from tab to our FS description
         */
        rc = mnt_fs_set_source(cxt->fs, mnt_fs_get_source(fs));
        if (!rc)
@@ -1254,7 +1231,32 @@ static int apply_tab(mnt_context *cxt, mnt_tab *tb, int direction)
        if (!rc && !mnt_fs_get_fstype(cxt->fs))
                rc = mnt_fs_set_fstype(cxt->fs, mnt_fs_get_fstype(fs));
 
-       if (!rc && cxt->optsmode != MNT_OPTSMODE_IGNORE) {
+       if (rc)
+               return rc;
+
+       if (cxt->optsmode & MNT_OMODE_IGNORE)
+               ;
+       else if (cxt->optsmode & MNT_OMODE_REPLACE) {
+               rc = mnt_fs_set_vfs_options(cxt->fs,
+                                       mnt_fs_get_vfs_options(fs));
+               if (!rc)
+                       rc = mnt_fs_set_fs_options(cxt->fs,
+                                       mnt_fs_get_fs_options(fs));
+               if (!rc)
+                       rc = mnt_fs_set_userspace_options(cxt->fs,
+                                       mnt_fs_get_userspace_options(fs));
+
+       } else if (cxt->optsmode & MNT_OMODE_APPEND) {
+               rc = mnt_fs_append_vfs_options(cxt->fs,
+                                       mnt_fs_get_vfs_options(fs));
+               if (!rc)
+                       rc = mnt_fs_append_fs_options(cxt->fs,
+                                       mnt_fs_get_fs_options(fs));
+               if (!rc)
+                       rc = mnt_fs_append_userspace_options(cxt->fs,
+                                       mnt_fs_get_userspace_options(fs));
+
+       } else if (cxt->optsmode & MNT_OMODE_PREPEND) {
                rc = mnt_fs_prepend_vfs_options(cxt->fs,
                                        mnt_fs_get_vfs_options(fs));
                if (!rc)
@@ -1264,9 +1266,9 @@ static int apply_tab(mnt_context *cxt, mnt_tab *tb, int direction)
                        rc = mnt_fs_prepend_userspace_options(cxt->fs,
                                        mnt_fs_get_userspace_options(fs));
        }
+
        if (!rc)
                cxt->flags |= MNT_FL_TAB_APPLIED;
-
        return rc;
 }
 
@@ -1281,20 +1283,25 @@ static int apply_tab(mnt_context *cxt, mnt_tab *tb, int direction)
  */
 int mnt_context_apply_fstab(mnt_context *cxt)
 {
-       int rc;
-       mnt_tab *fstab, *mtab;
+       int rc = -1;
+       mnt_tab *tab = NULL;
        const char *src = NULL, *tgt = NULL;
 
        assert(cxt);
        assert(cxt->fs);
 
-       if (!cxt || !cxt->fs)
+       if (!cxt)
                return -EINVAL;
 
        if (cxt->flags & MNT_FL_TAB_APPLIED)
                return 0;
 
-       DBG(CXT, mnt_debug_h(cxt, "appling fstab"));
+       if (mnt_context_is_restricted(cxt)) {
+               DBG(CXT, mnt_debug_h(cxt, "force fstab usage for non-root users"));
+               cxt->optsmode = MNT_OMODE_USER;
+
+       } else if (cxt->optsmode == 0)
+               cxt->optsmode = MNT_OMODE_AUTO;
 
        if (cxt->fs) {
                src = mnt_fs_get_source(cxt->fs);
@@ -1302,35 +1309,30 @@ int mnt_context_apply_fstab(mnt_context *cxt)
        }
 
        /* fstab is not required if source and target are specified */
-       if (src && tgt && !(cxt->optsmode == MNT_OPTSMODE_FORCE ||
-                           cxt->optsmode == MNT_OPTSMODE_MTABFORCE))
+       if (src && tgt && !(cxt->optsmode == MNT_OMODE_FORCE))
                return 0;
 
        DBG(CXT, mnt_debug_h(cxt,
                "trying to apply fstab (src=%s, target=%s)", src, tgt));
 
-       rc = mnt_context_get_fstab(cxt, &fstab);
-       if (rc)
-               goto err;
-
        /* let's initialize cxt->fs */
        mnt_context_get_fs(cxt);
 
        /* try fstab */
-       rc = apply_tab(cxt, fstab, MNT_ITER_FORWARD);
+       if (cxt->optsmode & MNT_OMODE_FSTAB) {
+               rc = mnt_context_get_fstab(cxt, &tab);
+               if (!rc)
+                       rc = apply_tab(cxt, tab, MNT_ITER_FORWARD);
+       }
 
        /* try mtab */
-       if (rc || (cxt->optsmode == MNT_OPTSMODE_MTABFORCE && is_remount(cxt))) {
-
-               rc = mnt_context_get_mtab(cxt, &mtab);
+       if (rc == -1 && (cxt->optsmode & MNT_OMODE_MTAB)) {
+               rc = mnt_context_get_mtab(cxt, &tab);
                if (!rc)
-                       rc = apply_tab(cxt, mtab, MNT_ITER_BACKWARD);
-               if (rc)
-                       goto err;
+                       rc = apply_tab(cxt, tab, MNT_ITER_BACKWARD);
        }
-       return 0;
-err:
-       DBG(CXT, mnt_debug_h(cxt, "failed to found entry in fstab/mtab"));
+       if (rc)
+               DBG(CXT, mnt_debug_h(cxt, "failed to found entry in fstab/mtab"));
        return rc;
 }
 

diff --git a/shlibs/mount/src/context_mount.c b/shlibs/mount/src/context_mount.c
index caad3e32feee131a2b018ac70df056914b45bcca..1180d8eb0b8da66f613ac6b066a3aeb89e14be8a 100644 (file)
--- a/shlibs/mount/src/context_mount.c
+++ b/shlibs/mount/src/context_mount.c
@@ -175,6 +175,12 @@ static int evaluate_permissions(mnt_context *cxt)
                /*
                 * user mount
                 */
+               if (!(cxt->flags & MNT_FL_TAB_APPLIED))
+               {
+                       DBG(CXT, mnt_debug_h(cxt, "fstab not applied, ignore user mount"));
+                       return -EPERM;
+               }
+
                if (u_flags & (MNT_MS_OWNER | MNT_MS_GROUP))
                        cxt->mountflags |= MS_OWNERSECURE;
 

diff --git a/shlibs/mount/src/mount.h.in b/shlibs/mount/src/mount.h.in
index 7710192a078d2d53c600dfbc1262efa9a6085e39..199549eb3550de8e7881ffa0e1b88851f0cc9690 100644 (file)
--- a/shlibs/mount/src/mount.h.in
+++ b/shlibs/mount/src/mount.h.in
@@ -312,10 +312,20 @@ extern mnt_fs *mnt_update_get_fs(mnt_update *upd);
 
 /* mode for mount options from fstab */
 enum {
-       MNT_OPTSMODE_AUTO = 0,          /* use options if source or target are not defined */
-       MNT_OPTSMODE_IGNORE,            /* never use mount options from fstab */
-       MNT_OPTSMODE_FORCE,             /* always use mount options from fstab */
-       MNT_OPTSMODE_MTABFORCE,         /* for MS_REMOUNT use always options from mountinfo/mtab */
+       MNT_OMODE_IGNORE  = (1 << 1),   /* ignore mtab/fstab options */
+       MNT_OMODE_APPEND  = (1 << 2),   /* append mtab/fstab options to existing options */
+       MNT_OMODE_PREPEND = (1 << 3),   /* prepend mtab/fstab options to existing options */
+       MNT_OMODE_REPLACE = (1 << 4),   /* replace existing options with options from mtab/fstab */
+
+       MNT_OMODE_FORCE   = (1 << 5),   /* always read mtab/fstab options */
+
+       MNT_OMODE_FSTAB   = (1 << 10),  /* read from fstab */
+       MNT_OMODE_MTAB    = (1 << 11),  /* read from mtab if fstab not enabled or failed */
+
+       /* default */
+       MNT_OMODE_AUTO   = (MNT_OMODE_PREPEND | MNT_OMODE_FSTAB | MNT_OMODE_MTAB),
+       /* non-root users */
+       MNT_OMODE_USER   = (MNT_OMODE_REPLACE | MNT_OMODE_FORCE | MNT_OMODE_FSTAB)
 };
 
 extern mnt_context *mnt_new_context(void);