# How to Contribute
-------
- [How to Contribute](#How to Contribute)
 \- [Sign the CLA](#Sign the CLA)
 \- [Steps of submitting patches](#Steps of submitting patches)
 \- [Use the unified patch format](#Use the unified patch format)
 \- [Define the patch format](#Define the patch format)
 \- [Examples](#Examples)
 \- [Email client - Thunderbird settings](#Email client - Thunderbird settings)
- [Linux kernel](#Linux kernel)
### Sign the CLA
-------
Before making any contributions to openEuler, sign the CLA first.
Address: [https://openeuler.org/en/cla.html](https://openeuler.org/en/cla.html)
### Steps of submitting patches
-------
**Step 1** Compile and test your patches.
**Step 2** Generate patches.
Your patches should be generated based on the latest openEuler branch using git-format-patch. If your patches are in a patchset, it is better to use the **--cover-letter** option to describe what the patchset does.
Use **scripts/checkpatch.pl** to ensure that no coding style issue exists.
In addition, ensure that your patches comply with the unified openEuler patch format described below.
**Step 3** Send your patches to the openEuler mailing list.
To do so, run the following command:
 `git send-email *.patch -to="kernel@openeuler.org" --suppress-cc=all`
*NOTE*: Add **--suppress-cc=all** if you use git-send-email; otherwise, the email will be copied to all people in the upstream community and mailing lists.
For details about how to send patches using git-send-email, see [https://git-scm.com/docs/git-send-email](https://git-scm.com/docs/git-send-email).
**Step 4** Mark "v1, v2, v3 ..." in your patch subject if you have multiple versions to send out.
Use the **--subject-prefix="PATCH v2"** option to add the v2 tag to the patchset.
 `git format-patch --subject-prefix="PATCH v2" -1`
Subject examples:
 Subject: [PATCH v2 01/27] fork: fix some -Wmissing-prototypes warnings
 Subject: [PATCH v3] ext2: improve scalability of bitmap searching
**Step 5** Upstream your kernel patches to the kernel community (recommended). openEuler will synchronize with the kernel master in a timely manner.
**Step 6** Sign your work - the Developer’s Certificate of Origin.
 Similar to the upstream kernel community, you also need to sign your patch.
 For details, see [https://www.kernel.org/doc/html/latest/process/submitting-patches.html](https://www.kernel.org/doc/html/latest/process/submitting-patches.html).
 The sign-off is a simple line at the end of the explanation of the patch, which certifies that you wrote it or otherwise have the right to pass it on as an open source patch. The rules are pretty simple. You can certify as below:
 Developer’s Certificate of Origin 1.1
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 By making a contribution to this project, I certify that:
 (a) The contribution was created in whole or in part by me and I have the right to submit it under the open source license indicated in the file;
 (b) The contribution is based upon previous work that, to the best of my knowledge, is covered under an appropriate open source license and I have the right under that license to submit that work with modifications, whether created in whole or in part by me, under the same open source license (unless I am permitted to submit under a different license), as indicated in the file;
 (c) The contribution was provided directly to me by some other person who certified (a), (b) or (c) and I have not modified it.
 (d) I understand and agree that this project and the contribution are public and that a record of the contribution (including all personal information I submit with it, including my sign-off) is maintained indefinitely and may be redistributed consistent with this project or the open source license(s) involved.
Then you add a line saying:
Signed-off-by: Random J Developer <random@developer.example.org>
Use your real name (sorry, no pseudonyms or anonymous contributions).
### Use the unified patch format
-------
Reasons:
1. Long term maintainability
 openEuler will merge massive patches. If all patches are merged by casual
 changelog formats without a unified format, the git logs will be messy, and
 then it is hard to figure out the original patches.
2. Kernel upgrade
 We definitely will upgrade our openEuler kernel in someday, so strict patch management
 will alleviate the pain to migrate patches during big upgrades.
3. Easy for script parsing
 Keyword highlighting is necessary for script parsing.
### Define the patch format
-------
[M] stands for "mandatory".
[O] stands for "option".
$category can be: bug preparation, bugfix, perf, feature, doc, other...
If category is feature, we need to add a feature name as below:
```cpp
category: feature
feature: YYY (the feature name)
```
If the patch is related to CVE or bugzilla, we need to add the corresponding tag as below (In general, it should include at least one of the following):
```cpp
CVE: $cve-id
bugzilla: $bug-id
```
Additional changelog should include at least one of the following:
1. Why we should apply this patch
2. What real problems in the product does this patch resolved
3. How could we reproduce this bug or how to test
4. Other useful information for help to understand this patch or problem
The detailed information is very useful for migrating a patch to another kernel branch.
Example for mainline patch:
```cpp
mainline inclusion [M]
from $mainline-version [M]
commit $id [M]
category: $category [M]
bugzilla: $bug-id [O]
CVE: $cve-id [O]
additional changelog [O]
--------------------------------
original changelog
Signed-off-by: $yourname <$yourname@huawei.com> [M]
($mainline-version could be mainline-3.5, mainline-3.6, etc...)
```
### Examples
-------
```cpp
mainline inclusion
from mainline-4.10
commit 0becc0ae5b42828785b589f686725ff5bc3b9b25
category: bugfix
bugzilla: 3004
CVE: N/A
The patch fixes a BUG_ON in the product: Injecting a single bit ECC error to the memory before system boot using hardware inject tools will cause a large amount of CMCI during system booting .
[ 1.146580] mce: [Hardware Error]: Machine check events logged
[ 1.152908] ------------[ cut here ]------------
[ 1.157751] kernel BUG at kernel/timer.c:951!
[ 1.162321] invalid opcode: 0000 [#1] SMP
-------------------------------------------------
original changelog
<original S-O-B>
Signed-off-by: Zhang San <zhangsan@huawei.com>
Tested-by: Li Si <lisi@huawei.com>
```
### Email client - Thunderbird settings
-------
If you are a new developer in the kernel community, it is highly recommended that you use the Thunderbird mail client.
1. Thunderbird Installation
 Obtain the English version of Thunderbird from [http://www.mozilla.org/]( http://www.mozilla.org/) and install it on your system.
 Download URL: https://www.thunderbird.net/en-US/thunderbird/all/
2. Settings
 2.1 Use the plain text format instead of the HTML format.
 Choose **Options > Account Settings > Composition & Addressing**, and do **NOT** select Compose message in HTML format.
 2.2 Editor settings
 **Tools > Options> Advanced > Config editor**
 \- To bring up the Thunderbird's registry editor, set **mailnews.send_plaintext_flowed** to **false**.
 \- Disable HTML Format: Set **mail.identity.id1.compose_html** to **false**.
 \- Enable UTF-8: Set **prefs.converted-to-utf8** to **true**.
 \- View messages in UTF-8: Set **mailnews.view_default_charset** to **UTF-8**.
 \- Set **mailnews.wraplength** to **9999** to avoid auto-wrap.
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
 https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.