nsenter: use USE_NAMESPACE_ID_SUPPORT macro for nsid feature

Replace direct HAVE_STRUCT_NSFS_FILE_HANDLE ifdefs with a
feature-specific USE_NAMESPACE_ID_SUPPORT macro that also
requires HAVE_PIDFD_OPEN, since the namespace ID support
depends on pidfd_open().

Addresses: https://github.com/util-linux/util-linux/pull/4044
Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/sys-utils/nsenter.c b/sys-utils/nsenter.c
index d6d9a58cd905d4b27d10ea362f451e539b46ac17..f93e75af278466748f05b818c54ba0d5f9efbe67 100644 (file)
--- a/sys-utils/nsenter.c
+++ b/sys-utils/nsenter.c
@@ -54,6 +54,10 @@
 #include "linux_version.h"
 #include "pidutils.h"
 
+#if defined(HAVE_STRUCT_NSFS_FILE_HANDLE) && defined(HAVE_PIDFD_OPEN)
+# define USE_NAMESPACE_ID_SUPPORT
+#endif
+
 static struct namespace_file {
        int nstype;
        const char *name;
@@ -177,7 +181,7 @@ static void open_target_fd(int *fd, const char *type, const char *path)
                err(EXIT_FAILURE, _("cannot open %s"), path);
 }
 
-#ifdef HAVE_STRUCT_NSFS_FILE_HANDLE
+#ifdef USE_NAMESPACE_ID_SUPPORT
 
 static struct file_handle nsfs_fh_tmpl = { 0 };
 static int nsfs_fd = -1;
@@ -248,12 +252,12 @@ static void open_target_fd_by_nsid(int *fd, const char *idstr)
                err(EXIT_FAILURE, _("cannot open namespace of id %"PRIu64),
                    ns_id);
 }
-#endif /* HAVE_STRUCT_NSFS_FILE_HANDLE */
+#endif /* USE_NAMESPACE_ID_SUPPORT */
 
 static void enable_nsfile(struct namespace_file *n, const char *path)
 {
        if (path) {
-#ifdef HAVE_STRUCT_NSFS_FILE_HANDLE
+#ifdef USE_NAMESPACE_ID_SUPPORT
                if (*path == ':')
                        open_target_fd_by_nsid(&n->fd, path + 1);
                else
@@ -855,7 +859,7 @@ int main(int argc, char *argv[])
        if (pid_fd >= 0)
                close(pid_fd);
 
-#ifdef HAVE_STRUCT_NSFS_FILE_HANDLE
+#ifdef USE_NAMESPACE_ID_SUPPORT
        if (nsfs_fd >= 0)
                close(nsfs_fd);
 #endif