Merge pull request #2149 from stb-tester/boot-self-symlink

sysroot: Support /boot on root or as seperate filesystem for syslinux and u-boot

src/libostree/ostree-sysroot-deploy.c

@@ -1994,6 +1994,12 @@ prepare_new_bootloader_link (OstreeSysroot  *sysroot,
   g_assert ((current_bootversion == 0 && new_bootversion == 1) ||
             (current_bootversion == 1 && new_bootversion == 0));
 
+  /* This allows us to support both /boot on a seperate filesystem to / as well
+   * as on the same filesystem. */
+  if (TEMP_FAILURE_RETRY (symlinkat (".", sysroot->sysroot_fd, "boot/boot")) < 0)
+    if (errno != EEXIST)
+      return glnx_throw_errno_prefix (error, "symlinkat");
+
   g_autofree char *new_target = g_strdup_printf ("loader.%d", new_bootversion);
 
   /* We shouldn't actually need to replace but it's easier to reuse