Re: [Libguestfs] [PATCH v3 8/8] lib/canonical-name.c: Hide EINVAL error from underlying API call.

On Thu, Sep 17, 2020 at 01:40:04PM +0100, Richard W.M. Jones wrote: >When guestfs_lvm_canonical_lv_name was called with a /dev/dm* or >/dev/mapper* name which was not an LV then a noisy error would be >printed. This would typically have happened with encrypted disks, and >now happens very noticably when inspecting Windows BitLocker- >encrypted guests. > >Using the modified error behaviour of this API from the previous >commit we can now hide that error in that specific case. (Even in >this case the underlying error message still gets logged in debug >output). >--- >lib/canonical-name.c | 9 +++++++-- >1 file changed, 7 insertions(+), 2 deletions(-) > >diff --git a/lib/canonical-name.c b/lib/canonical-name.c >index 052bbf12c..e0c7918b4 100644 >--- a/lib/canonical-name.c >+++ b/lib/canonical-name.c >@@ -46,9 +46,14 @@ guestfs_impl_canonical_device_name (guestfs_h *g, const char *device) > } > else if (STRPREFIX (device, "/dev/mapper/") || > STRPREFIX (device, "/dev/dm-")) { >- /* XXX hide errors */ >+ guestfs_push_error_handler (g, NULL, NULL); Doesn't this hide the other error which might be important as well? The only one I can find it the file not existing, but it means this function might fail without an error message if I understand it correctly.

> ret = guestfs_lvm_canonical_lv_name (g, device); >- if (ret == NULL) >+ guestfs_pop_error_handler (g); >+ /* EINVAL is expected if the device is somelike a LUKS- or >+ * BitLocker-encrypted volume, so simply return the original >+ * name in that case. >+ */ >+ if (ret == NULL && guestfs_last_errno (g) == EINVAL) > ret = safe_strdup (g, device);