chore: Use geteuid() instead of getuid() to check privilege

src/libostree/ostree-bootloader-zipl.c

@@ -432,7 +432,7 @@ _ostree_bootloader_zipl_post_bls_sync (OstreeBootloader *bootloader, int bootver
   // This can happen in a unit testing environment; at some point what we want to do here
   // is move all of the zipl logic to a systemd unit instead that's keyed of
   // ostree-finalize-staged.service.
-  if (getuid () != 0)
+  if (!ot_util_process_privileged ())
     return TRUE;
 
   // If we're in a booted deployment, we don't need to spawn a container.

src/libostree/ostree-repo-commit.c

@@ -1658,7 +1658,7 @@ ostree_repo_prepare_transaction (OstreeRepo *self, gboolean *out_transaction_res
   self->reserved_blocks = reserved_bytes / self->txn.blocksize;
 
   /* Use the appropriate free block count if we're unprivileged */
-  guint64 bfree = (getuid () != 0 ? stvfsbuf.f_bavail : stvfsbuf.f_bfree);
+  guint64 bfree = (ot_util_process_privileged () ? stvfsbuf.f_bfree : stvfsbuf.f_bavail);
   if (bfree > self->reserved_blocks)
     self->txn.max_blocks = bfree - self->reserved_blocks;
   else

src/libostree/ostree-sysroot.c

@@ -263,7 +263,7 @@ _ostree_sysroot_enter_mount_namespace (OstreeSysroot *self, GCancellable *cancel
     return TRUE;
 
   /* Do nothing if we're not privileged */
-  if (getuid () != 0)
+  if (!ot_util_process_privileged ())
     return TRUE;
 
   /* We also assume operating on non-booted roots won't have a readonly sysroot */

src/libotutil/ot-unix-utils.c

@@ -102,3 +102,10 @@ ot_util_path_split_validate (const char *path, GPtrArray **out_components, GErro
   ot_transfer_out_value (out_components, &ret_components);
   return TRUE;
 }
+
+/* Check if current process is privileged */
+gboolean
+ot_util_process_privileged (void)
+{
+  return geteuid() == 0;
+}

src/libotutil/ot-unix-utils.h

@@ -39,4 +39,6 @@ gboolean ot_util_filename_validate (const char *name, GError **error);
 
 gboolean ot_util_path_split_validate (const char *path, GPtrArray **out_components, GError **error);
 
+gboolean ot_util_process_privileged (void);
+
 G_END_DECLS

src/ostree/ot-main.c

@@ -116,7 +116,7 @@ maybe_setup_mount_namespace (gboolean *out_ns, GError **error)
   *out_ns = FALSE;
 
   /* If we're not root, then we almost certainly can't be remounting anything */
-  if (getuid () != 0)
+  if (!ot_util_process_privileged ())
     return TRUE;
 
   /* If the system isn't booted via libostree, also nothing to do */
@@ -580,7 +580,7 @@ ostree_admin_sysroot_load (OstreeSysroot *sysroot, OstreeAdminBuiltinFlags flags
       /* Only require root if we're manipulating a booted sysroot. (Mostly
        * useful for the test suite)
        */
-      if (booted && getuid () != 0)
+      if (booted && !ot_util_process_privileged ())
         {
           g_set_error (error, G_IO_ERROR, G_IO_ERROR_PERMISSION_DENIED,
                        "You must be root to perform this command");