On Wed, Nov 14, 2018 at 11:45 AM, Nikolaus Rath <Nikolaus@xxxxxxxx> wrote: > Hi, > > If I understand Documentation/filesystems/path-lookup.md correctly, then > the "symlinks" in /proc/self/fd/NN are not true symlinks but just > presented as such to userspace. Does this mean that I can access (e.g., > open(), setxattr(), or chmod()) these files without the possibility of > race conditions? I.e., there is no way for someone to rename the target > after the kernel has "looked up" the target but before the operation is > applied? Exactly. The only limitation is that if the target is a symlink (fd opened with O_PATH) then the neither the symlink following, nor the non-following variants will do the right thing (see *xattr ops in passthrough_ll for example). > Secondly, under which conditions can I open the files in /proc? Does > this still work if the destination file has been unlinked? Yes. > Does it > always follow renames? What if I mounted something over the destination? It works in all those cases. Thanks, Miklos
