Hi On Tue, Jun 16, 2020 at 12:35 PM Michal Privoznik <mpriv...@redhat.com> wrote:
> Problem with g_get_host_name() is that on the first call it saves > the hostname into a global variable and from then on, every > subsequent call returns the saved hostname. Even if the hostname > changes. This doesn't play nicely with guest agent, because if > the hostname is acquired before the guest is set up (e.g. on the > first boot, or before DHCP) we will report old, invalid hostname. > > Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1845127 lgtm, Reviewed-by: Marc-André Lureau <marcandre.lur...@redhat.com> (fwiw, I opened a glib issue: https://gitlab.gnome.org/GNOME/glib/-/issues/2130) > > Signed-off-by: Michal Privoznik <mpriv...@redhat.com> > --- > qga/commands.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++---- > 1 file changed, 52 insertions(+), 4 deletions(-) > > diff --git a/qga/commands.c b/qga/commands.c > index efc8b90281..ce3c2041a6 100644 > --- a/qga/commands.c > +++ b/qga/commands.c > @@ -512,14 +512,62 @@ int ga_parse_whence(GuestFileWhence *whence, Error > **errp) > return -1; > } > > +#ifndef HOST_NAME_MAX > +# ifdef _POSIX_HOST_NAME_MAX > +# define HOST_NAME_MAX _POSIX_HOST_NAME_MAX > +# else > +# define HOST_NAME_MAX 255 > +# endif > +#endif > + > GuestHostName *qmp_guest_get_host_name(Error **errp) > { > GuestHostName *result = NULL; > - gchar const *hostname = g_get_host_name(); > - if (hostname != NULL) { > - result = g_new0(GuestHostName, 1); > - result->host_name = g_strdup(hostname); > + g_autofree char *hostname = NULL; > + > + /* > + * We want to avoid using g_get_host_name() because that > + * caches the result and we wouldn't reflect changes in the > + * host name. > + */ > + > +#ifndef G_OS_WIN32 > + long len = -1; > + > +#ifdef _SC_HOST_NAME_MAX > + len = sysconf(_SC_HOST_NAME_MAX); > +#endif /* _SC_HOST_NAME_MAX */ > + > + if (len < 0) { > + len = HOST_NAME_MAX; > } > + > + hostname = g_malloc0(len + 1); > + > + if (gethostname(hostname, len) < 0) { > + return NULL; > + } > + > +#else /* G_OS_WIN32 */ > + > + wchar_t tmp[MAX_COMPUTERNAME_LENGTH + 1]; > + DWORD size = G_N_ELEMENTS(tmp); > + > + if (GetComputerNameW(tmp, &size) != 0) { > + /* > + * Indeed, on Windows retval of zero means failure > + * and nonzero means success. > + */ > + hostname = g_utf16_to_utf8(tmp, size, NULL, NULL, NULL); > + } > +#endif /* G_OS_WIN32 */ > + > + if (!hostname) { > + hostname = g_strdup("localhost"); > + } > + > + result = g_new0(GuestHostName, 1); > + result->host_name = g_steal_pointer(&hostname); > return result; > } > > -- > 2.26.2 > > > -- Marc-André Lureau
