[Libguestfs] [PATCH] fish: edit: write to the real file name

[Richard W.M. Jones]

On Mon, Sep 01, 2014 at 11:54:08AM +0200, Pino Toscano wrote:
> When saving, resolve the path of the file being edited and use that as
> real target to write to. Otherwise, if the file name is a symlink then
> it will be replaced by a regular file with the new content, leaving the
> old file untouched.
> 
> Extend test-edit.sh to check for this situation.
> ---
>  fish/file-edit.c  | 15 ++++++++++++++-
>  fish/test-edit.sh | 12 +++++++++++-
>  2 files changed, 25 insertions(+), 2 deletions(-)
> 
> diff --git a/fish/file-edit.c b/fish/file-edit.c
> index e6d25f5..dd2272b 100644
> --- a/fish/file-edit.c
> +++ b/fish/file-edit.c
> @@ -216,11 +216,24 @@ do_download (guestfs_h *g, const char *filename, char **tempfile)
>  }
>  
>  static int
> -do_upload (guestfs_h *g, const char *filename, const char *tempfile,
> +do_upload (guestfs_h *g, const char *fn, const char *tempfile,
>             const char *backup_extension)
>  {
> +  CLEANUP_FREE char *filename = NULL;
>    CLEANUP_FREE char *newname = NULL;
>  
> +  /* Resolve the file name and write to the actual target, since
> +   * that is the file it was opened earlier; otherwise, if it is
> +   * a symlink it will be overwritten by a regular file with the
> +   * new content.
> +   *
> +   * Theoretically realpath should work, but just check again
> +   * to be safe.
> +   */
> +  filename = guestfs_realpath (g, fn);
> +  if (filename == NULL)
> +    return -1;
> +
>    /* Upload to a new file in the same directory, so if it fails we
>     * don't end up with a partially written file.  Give the new file
>     * a completely random name so we have only a tiny chance of
> diff --git a/fish/test-edit.sh b/fish/test-edit.sh
> index 34bfc9d..9d7ab9d 100755
> --- a/fish/test-edit.sh
> +++ b/fish/test-edit.sh
> @@ -43,6 +43,12 @@ cat /file.txt
>  stat /file.txt | grep mode:
>  stat /file.txt | grep uid:
>  stat /file.txt | grep gid:
> +echo ==========
> +write /file-2.txt "symlink test\n"
> +ln-s /file-2.txt /symlink-2.txt
> +edit /symlink-2.txt
> +is-symlink /symlink-2.txt
> +cat /symlink-2.txt
>  EOF
>  )
>  
> @@ -51,7 +57,11 @@ second line of text
>  
>  mode: 33152
>  uid: 10
> -gid: 11" ]; then
> +gid: 11
> +==========
> +true
> +symlink test
> +second line of text" ]; then
>      echo "$0: error: output of guestfish after edit command did not match expected output"
>      echo "$output"
>      exit 1
> -- 
> 1.9.3

ACK.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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