Licensing
Component licenses, redistribution obligations, recommended attribution, and name and logo use.
On this page
Component licenses
The repository uses multiple licenses. The root LICENSE is Apache License 2.0. LICENSE-NOTICE lists XTOS user-space material and separately identifies the kernel, patches, and BusyBox. Read each file SPDX notice too.
| Path | License | Basis |
|---|---|---|
| sdk/libxtos-rt, libxtos-signal, libxtos-bci | Apache-2.0 | Source and headers are listed in section 1 of LICENSE-NOTICE. |
| tools/, examples/, system/, scripts/ | Apache-2.0 | XTOS user-space tools, examples, rootfs, and automation. |
| kernel/xtos_defconfig | Apache-2.0 | The configuration fragment separately listed by LICENSE-NOTICE. |
| kernel/linux/ | GPL-2.0 WITH Linux-syscall-note | kernel/linux/COPYING; individual files may have other SPDX licenses. |
| kernel/patches/ | GPL-2.0 | PREEMPT_RT and XTOS kernel-side integration patches. |
| userspace/busybox/ | GPL-2.0, version 2 only | The separate LICENSE for BusyBox 1.37.0. |
Apache-2.0 user space
Apache-2.0 permits copying, modifying, sublicensing, and distributing source or object forms within its terms, and provides the stated contributor patent license. Distributions of XTOS SDKs and tools retain licenses, attribution, NOTICE, and modification notices.
- Provide the Apache License 2.0 text with the copy.
- State modifications prominently in changed files.
- Retain applicable copyright, patent, trademark, and attribution notices.
- Retain a readable NOTICE copy when the distribution includes NOTICE material.
- Apache-2.0 grants no general trademark rights; patent-litigation termination follows section 3 of LICENSE.
/* SPDX-License-Identifier: Apache-2.0 */
/* Describe modifications in the changed file. */GPL-2.0 kernel and BusyBox
kernel/linux/COPYING uses GPL-2.0 WITH Linux-syscall-note. Kernel patches use GPL-2.0. BusyBox LICENSE states that this version may be distributed under GPL version 2 only, not version 2 or later.
| Distribution | Materials |
|---|---|
| Source | Retain copyright, license, warranty, modification notices, and the applicable GPL text. |
| Kernel, module, or BusyBox binary | Provide corresponding source under GPL-2.0 section 3; bundling complete corresponding source is the direct option. |
| Corresponding source | Include modified source, interface definitions, build/install scripts, configuration, and kernel patches. |
| Written offer | Under GPL-2.0 section 3(b), the written offer lasts at least three years and must meet its third-party source-provision conditions. |
Putting BusyBox, the Apache SDK, and the kernel in one initramfs does not merge their licenses. A system-image distribution must provide the required materials for the kernel, BusyBox, SDK, and tools; the root LICENSE alone is insufficient.
UAPI boundary
LICENSE-NOTICE describes the Apache-2.0 user-space SDK using GPL kernel services through ioctl and syscall ABI without linking XTOS kernel implementation. Linux-syscall-note covers ordinary syscall use; it does not relicense copied kernel drivers in user space.
| Interface or implementation | License and boundary |
|---|---|
| kernel/linux/include/uapi/linux/xtos_bci.h | GPL-2.0 WITH Linux-syscall-note; defines the integer ioctl ABI. |
| sdk/libxtos-bci/include/xtos/bci_uapi.h | LICENSE-NOTICE lists the SDK header as Apache-2.0; it must match the kernel ABI. |
| User-space session.c | open/read/ioctl/mmap use kernel services; this does not link kernel driver code. |
| XTOS kernel scheduler and BCI | Kernel-side GPL-2.0; retain the original file licenses. |
Distribution materials
Inventory components for the exact commit and artifacts. Retain license texts, component boundaries, and modification records. Images, modules, BusyBox, SDK archives, and tools may share a package, but licenses and corresponding source must match each component.
git rev-parse HEAD
git show HEAD:LICENSE-NOTICE
git show HEAD:LICENSE
git show HEAD:kernel/linux/COPYING
git show HEAD:kernel/linux/LICENSES/preferred/GPL-2.0
git show HEAD:kernel/linux/LICENSES/exceptions/Linux-syscall-note
git show HEAD:userspace/busybox/LICENSE
git show HEAD:kernel/linux/include/uapi/linux/xtos_bci.h- Retain root LICENSE, LICENSE-NOTICE, kernel COPYING, GPL, and syscall-note texts.
- For BusyBox distributions, retain its separate LICENSE and source and changes matching the binary.
- Check SPDX, upstream attribution, and modification notices; do not relabel third-party files as Apache-2.0.
- Match the source commit, configuration, kernel patches, and build scripts to the artifacts.
Source: LICENSE-NOTICE, LICENSE, kernel/linux/COPYING, kernel/linux/LICENSES/preferred/GPL-2.0, kernel/linux/LICENSES/exceptions/Linux-syscall-note, userspace/busybox/LICENSE, and kernel/linux/include/uapi/linux/xtos_bci.h.
Attribution
Commercial use, product integration, and modification follow the licenses of the adopted components. Commercial use alone does not create an additional fee, approval, or mandatory logo-display requirement. This guide does not add software-license conditions to GPL-2.0 or Apache-2.0.
Redistribution must meet the applicable copyright, license, attribution, modification-notice, and corresponding-source obligations. Apache-2.0 section 4(d) permits applicable NOTICE attribution in accompanying files, documentation, or a display where third-party notices normally appear; it does not impose universal prominent UI logo placement.
- Project name: OpenXTOS / XTOS; identify the system or components actually integrated.
- The actual upstream version and known source commit, displayed separately from the downstream product version.
- Project website: https://xtos.cn.
- Modification status, a change summary, and the actual product vendor; a modified version should not masquerade as an official release.
For SDK-only use such as libxtos-rt, state that the product includes the component, not that it adopts the complete XTOS system. Headless devices may provide the recommended information through a management interface, version command, manual, or accompanying open-source notices.
Names and logos
The XTOS/OpenXTOS names and official logos identify the project. Software licenses do not automatically grant rights to use them as a downstream product name, primary brand, certification mark, or co-brand. Descriptive attribution and brand permission are separate.
Accurate, proportionate textual descriptions such as “based on OpenXTOS” or “includes libxtos-rt” do not require an additional approval imposed by this guide. Descriptive use permitted by applicable law is not restricted. Apache-2.0 section 6 preserves reasonable and customary use of names or marks in describing the origin of the Work and reproducing the content of NOTICE where applicable. Do not imply project provision, certification, sponsorship, or endorsement.
Except for uses permitted by Apache-2.0 section 6 or other applicable law, or already authorized, obtain written permission for official logo use as a primary product brand, certification mark, co-brand, or other use beyond reasonable source identification. Specify scope, placement, asset, size, version attribution, term, and withdrawal conditions. Logo permission must not restrict GPL-2.0 or Apache-2.0 code rights.
- After authorization, use the supplied official logo without distortion, removal of identifying features, or unapproved color changes.
- Identify the downstream vendor and modifications; do not substitute the downstream product version for the upstream XTOS version.
- Attribution or logo permission does not imply official certification, support, or warranty.
Attribution examples
These are recommended templates, not additional licenses. They do not require logo approval when used only as reasonable source attribution. Replace placeholders with the actual version, components, modifications, and vendor. Attribution should be accessible and readable in normal use, not rendered with illegible text or colors.
本产品基于 OpenXTOS [上游版本] 开发。
整合范围：[完整系统及组件清单]。
修改情况：[修改摘要或未修改]。
项目官网：https://xtos.cn
产品提供方：[厂商名称]。
本产品不代表 XTOS 官方发行、认证或背书。
This product is based on OpenXTOS [upstream version].
Integration: [system and component list].
Modifications: [summary or none].
Project website: https://xtos.cn
Product vendor: [vendor name].
This is not an official XTOS release, certification, or endorsement.本产品包含 OpenXTOS 的 libxtos-rt [库版本]。
上游版本/提交：[实际采用的信息]。
项目官网：https://xtos.cn
修改情况：[修改摘要或未修改]。
This product includes OpenXTOS libxtos-rt [library version].
Upstream version/commit: [actual adopted source].
Project website: https://xtos.cn
Modifications: [summary or none].Files and contact
Provide LICENSE, LICENSE-NOTICE, applicable NOTICE material, and third-party licenses/notices as required in source and artifact distributions. Record VERSION, source commit, components, and changes. Including TRADEMARKS.md is recommended; it is not an additional license restricting GPL/Apache rights.
Project maintainer: Jiaxing ITADD Group Co., Ltd. Website: https://xtos.cn. Project contact: org@dcom.si.
Project contact is for routing enquiries, not a logo authorization. Any specific permission must be confirmed in writing by the party with the relevant authority.