Raul Miller: "Bug#1744: dpkg: cannot scan updates directory
`/var/lib/dpkg/updates/': No such file or directory" (Oct 26, 18:24):
> There's a problem with the umsdos file system that prevents scandir(3)
> from working right -- it gives ENOENT instead of EOF upon successful
> termination. This occurs because readdir returns ENOENT upon reaching
> the end of the directory. The msdos file system has the same
> problem. Here's a patch:
>
> --- linux-1.3.29/fs/msdos/dir.c.dist Thu Oct 26 18:11:01 1995
> +++ linux-1.3.29/fs/msdos/dir.c Thu Oct 26 18:12:34 1995
> @@ -86,7 +86,7 @@
> filp->f_pos = 0;
> }
> if (filp->f_pos & (sizeof(struct msdos_dir_entry)-1))
> - return -ENOENT;
> + return NULL;
> bh = NULL;
> while ((ino = msdos_get_entry(inode,&filp->f_pos,&bh,&de)) > -1) {
> if (!IS_FREE(de->name)
The above doesn't look like the right fix: -ENOENT may not be the right
value to return, but the above return value is meant to catch a bogus
file position pointer rather than catch the end of the file. A better
error might be -EINVAL for that case (it means that somebody did a seek
with a bad value at some point).
> --- linux-1.3.29/fs/umsdos/dir.c.dist Thu Oct 26 18:11:02 1995
> +++ linux-1.3.29/fs/umsdos/dir.c Thu Oct 26 18:13:51 1995
> @@ -259,7 +259,7 @@
> }
> /*
> Read count directory entries from directory filp
> - Return a negative value from linux/errno.h.
> + Return a NULL to indicate end of file
> Return > 0 if success (the amount of byte written to dirent)
> */
> static int UMSDOS_readdir(
> @@ -284,7 +284,7 @@
> }
> PRINTK (("UMSDOS_readdir out %d count %d pos %Ld\n",ret,count
> ,filp->f_pos));
> - return count == 0 ? -ENOENT : ret;
> + return count == 0 ? NULL : ret;
> }
> /*
> Complete the inode content with info from the EMD file
How about
return count ? : ret;
instead? At the very least a NULL is definitely wrong, as we're
returning an integer, not a pointer.
Linus
