Correct resolution of non-virtual directory names on Android

* src/androidvfs.c (android_vfs_canonicalize_name): Correct
return value in cases of underflowing the directory stack.
(android_unix_name): Reset vnode operations vector of copied
vnodes to their standard value, and exclude virtual directories
from subdirectories of the root directory's parent directory.
(android_root_name): Adjust to match.

(cherry picked from commit 6a162be6a8f4681d3465fac7573b9f42cfbeaefb)

diff --git a/src/androidvfs.c b/src/androidvfs.c
index d28a74918f6fb68ddb84b22b19c147f9abf2f6a0..28a239205331684df72922d55278cf68492097d1 100644 (file)
--- a/src/androidvfs.c
+++ b/src/androidvfs.c
@@ -458,7 +458,7 @@ static char *
 android_vfs_canonicalize_name (char *name, size_t *length)
 {
   size_t nellipsis, i;
-  char *last_component, *prev_component, *fill, *orig_name;
+  char *last_component, *prec_component, *fill, *orig_name;
   size_t size;
 
   /* Special case described in the last paragraph of the comment
@@ -474,8 +474,8 @@ android_vfs_canonicalize_name (char *name, size_t *length)
 
   nellipsis = 0; /* Number of ellipsis encountered within the current
                    file name component, or -1.  */
-  prev_component = NULL; /* Pointer to the separator character of
-                           the component immediately before the
+  prec_component = NULL; /* Pointer to the separator character of the
+                           component immediately preceding the
                            component currently being written.  */
   last_component = name; /* Pointer to the separator character of
                            the component currently being read.  */
@@ -502,31 +502,36 @@ android_vfs_canonicalize_name (char *name, size_t *length)
            {
              /* .. */
 
-             if (!prev_component)
-               goto parent_vnode;
+             if (!prec_component)
+               {
+                 /* Return the content of the component, i.e. the text
+                    _after_ this separator.  */
+                 i++;
+                 goto parent_vnode;
+               }
 
              /* Return to the last component.  */
-             fill = prev_component;
+             fill = prec_component;
 
-             /* Restore last_component to prev_component, and
-                prev_component back to the component before that.  */
-             last_component = prev_component;
+             /* Restore last_component to prec_component, and
+                prec_component back to the component before that.  */
+             last_component = prec_component;
 
-             if (last_component != name)
-               prev_component = memrchr (name, '/',
-                                         last_component - name - 1);
+             if (last_component != orig_name)
+               prec_component = memrchr (orig_name, '/',
+                                         last_component - orig_name - 1);
              else
-               prev_component = NULL;
+               prec_component = NULL;
 
-             /* prev_component may now be NULL.  If last_component is
-                the same as NAME, then fill has really been returned
-                to the beginning of the string, so leave it be.  But
-                if it's something else, then it must be the first
-                separator character in the string, so set
-                prev_component to NAME itself.  */
+             /* prec_component may now be NULL.  If last_component is
+                identical to the initial value of NAME, then fill has
+                really been returned to the beginning of the string, so
+                leave it be.  But if it's something else, then it must
+                be the first separator character in the string, so set
+                prec_component to this initial value itself.  */
 
-             if (!prev_component && last_component != name)
-               prev_component = name;
+             if (!prec_component && last_component != orig_name)
+               prec_component = orig_name;
            }
          else if (nellipsis == 1)
            /* If it's ., return to this component.  */
@@ -536,7 +541,7 @@ android_vfs_canonicalize_name (char *name, size_t *length)
              /* Record the position of the last directory separator,
                 so NAME can be overwritten from there onwards if `..'
                 or `.' are encountered.  */
-             prev_component = last_component;
+             prec_component = last_component;
              last_component = fill;
            }
 
@@ -568,12 +573,12 @@ android_vfs_canonicalize_name (char *name, size_t *length)
     {
       /* .. */
 
-      if (!prev_component)
+      if (!prec_component)
        /* Look up the rest of the vnode in its parent.  */
        goto parent_vnode;
 
       /* Return to the last component.  */
-      fill = prev_component;
+      fill = prec_component;
       nellipsis = -2;
     }
   else if (nellipsis == 1)
@@ -684,19 +689,20 @@ android_unix_name (struct android_vnode *vnode, char *name,
   input = (struct android_unix_vnode *) vnode;
   remainder = android_vfs_canonicalize_name (name, &length);
 
-  /* If remainder is set, it's a name relative to the parent
-     vnode.  */
+  /* If remainder is set, it's a name relative to the parent vnode.  */
   if (remainder)
     goto parent_vnode;
 
   /* Create a new unix vnode.  */
   vp = xmalloc (sizeof *vp);
 
-  /* If name is empty, duplicate the current vnode.  */
+  /* If name is empty, duplicate the current vnode, but reset its file
+     operation vector to that for Unix vnodes.  */
 
   if (length < 1)
     {
       memcpy (vp, vnode, sizeof *vp);
+      vp->vnode.ops = &unix_vfs_ops;
       vp->name = xstrdup (vp->name);
       return &vp->vnode;
     }
@@ -748,7 +754,7 @@ android_unix_name (struct android_vnode *vnode, char *name,
     vnode = &root_vnode.vnode;
   else
     {
-      /* Create a temporary asset vnode within the parent and use it
+      /* Create a temporary unix vnode within the parent and use it
          instead.  First, establish the length of vp->name before its
          last component.  */
 
@@ -783,7 +789,9 @@ android_unix_name (struct android_vnode *vnode, char *name,
       return vnode;
     }
 
-  return (*vnode->ops->name) (vnode, remainder, strlen (remainder));
+  /* Virtual directories must be ignored in accessing the root directory
+     through a Unix subdirectory of the root, as, `/../' */
+  return android_unix_name (vnode, remainder, strlen (remainder));
 }
 
 /* Create a Unix vnode representing the given file NAME.  Use this
@@ -6624,6 +6632,7 @@ android_root_name (struct android_vnode *vnode, char *name,
   size_t i;
   Lisp_Object file_name;
   struct android_vnode *vp;
+  struct android_unix_vnode *unix_vp;
 
   /* Skip any leading separator in NAME.  */
 
@@ -6706,7 +6715,18 @@ android_root_name (struct android_vnode *vnode, char *name,
        }
     }
 
-  /* Otherwise, continue searching for a vnode normally.  */
+  /* Otherwise, continue searching for a vnode normally, but duplicate
+     the vnode manually if length is 0, as `android_unix_name' resets
+     the vnode operation vector in copies.  */
+
+  if (!length)
+    {
+      unix_vp = xmalloc (sizeof *unix_vp);
+      memcpy (unix_vp, vnode, sizeof *unix_vp);
+      unix_vp->name = xstrdup (unix_vp->name);
+      return &unix_vp->vnode;
+    }
+
   return android_unix_name (vnode, name, length);
 }