Re: [Libguestfs] [libguestfs PATCH 2/7] lib/launch-libvirt: support networking with passt

We generate the <interface type="user"> element on libvirt 3.8.0+ already. For selecting passt rather than SLIRP, we only need to insert the child element <backend type='passt'>. Make that child element conditional on libvirt 9.0.0+, plus "passt --help" being executable. For the latter, place the new helper function guestfs_int_passt_runnable() in "lib/launch.c" -- we're going to use the same function for the direct backend as well. This change exposes a number of (perceived) shortcomings in libvirt; I've filed <https://bugzilla.redhat.com/show_bug.cgi?id=2222766> about those. Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2184967 Signed-off-by: Laszlo Ersek <lersek(a)redhat.com&gt; --- lib/guestfs-internal.h | 1 + lib/launch-libvirt.c | 11 ++++++++ lib/launch.c | 28 ++++++++++++++++++++ 3 files changed, 40 insertions(+) diff --git a/lib/guestfs-internal.h b/lib/guestfs-internal.h index 4be351e3d3cc..a6c4266ad3fe 100644 --- a/lib/guestfs-internal.h +++ b/lib/guestfs-internal.h @@ -703,6 +703,7 @@ extern void guestfs_int_unblock_sigterm (void); extern int guestfs_int_create_socketname (guestfs_h *g, const char *filename, char (*sockname)[UNIX_PATH_MAX]); extern void guestfs_int_register_backend (const char *name, const struct backend_ops *); extern int guestfs_int_set_backend (guestfs_h *g, const char *method); +extern bool guestfs_int_passt_runnable (guestfs_h *g); /* Close all file descriptors matching the condition. */ #define close_file_descriptors(cond) do { \ diff --git a/lib/launch-libvirt.c b/lib/launch-libvirt.c index d4bf1a8ff242..994909a35f2d 100644 --- a/lib/launch-libvirt.c +++ b/lib/launch-libvirt.c @@ -1414,6 +1414,17 @@ construct_libvirt_xml_devices (guestfs_h *g, guestfs_int_version_ge (&params->data->libvirt_version, 3, 8, 0)) { start_element ("interface") { attribute ("type", "user"); + /* If libvirt is 9.0.0+ and "passt" is available, ask for passt rather + * than SLIRP (RHBZ#2184967). Note that this causes some + * appliance-visible changes (although network connectivity is certainly + * functional); refer to RHBZ#2222766 about those. + */ + if (guestfs_int_version_ge (&params->data->libvirt_version, 9, 0, 0) && + guestfs_int_passt_runnable (g)) { + start_element ("backend") { + attribute ("type", "passt"); + } end_element (); + } start_element ("model") { attribute ("type", "virtio"); } end_element (); diff --git a/lib/launch.c b/lib/launch.c index 6e08b12006da..94c8f676d8bd 100644 --- a/lib/launch.c +++ b/lib/launch.c @@ -36,6 +36,7 @@ #include <signal.h> #include <sys/stat.h> #include <sys/types.h> +#include <sys/wait.h> #include <errno.h> #include <assert.h> #include <libintl.h> @@ -414,6 +415,33 @@ guestfs_int_set_backend (guestfs_h *g, const char *method) return 0; } +/** + * Return C<true> if we can call S<C<passt --help>>, and it exits with status + * C<0> or C<1>. + * + * (At least C<passt-0^20230222.g4ddbcb9-2.el9_2.x86_64> terminates with status + * C<1> in response to "--help", which is arguably wrong, and potentially + * subject to change, but it doesn't really matter.) + */ +bool +guestfs_int_passt_runnable (guestfs_h *g) +{ + CLEANUP_CMD_CLOSE struct command *cmd = NULL; + int r, ex; + + cmd = guestfs_int_new_command (g); + if (cmd == NULL) + return false; + + guestfs_int_cmd_add_string_unquoted (cmd, "passt --help");

+ r = guestfs_int_cmd_run (cmd); + if (r == -1 || !WIFEXITED (r)) + return false; + + ex = WEXITSTATUS (r); + return ex == 0 || ex == 1; +} + /* This hack is only required to make static linking work. See: * https://stackoverflow.com/questions/1202494/why-doesnt-attribute-construc... */ _______________________________________________ Libguestfs mailing list Libguestfs(a)redhat.com https://listman.redhat.com/mailman/listinfo/libguestfs