我不小心格式化了EFI分区，导致无法启动 Grub。

1. 使用Ubuntu镜像引导到安装界面，选择试用Ubuntu。
2. 打开终端，输入以下命令。
```bash
sudo mount /dev/sdb1 /mnt
sudo mount /dev/sdb2 /mnt/boot/efi

sudo mount --bind /dev /mnt/dev
sudo mount --bind /dev/pts /mnt/dev/pts
sudo mount --bind /proc /mnt/proc
sudo mount --bind /sys /mnt/sys

sudo chroot /mnt
grub-install --target=x86_64-efi /dev/sdb
grub-install --recheck /dev/sdb
exit

sudo umount /mnt/sys
sudo umount /mnt/proc
sudo umount /mnt/dev/pts
sudo umount /mnt/dev
sudo umount /mnt
```

3. 重启系统


> 还有另外一种不需要 chroot 的方法（未尝试）
```bash
# sudo apt install grub-efi

sudo mount /dev/sdb1 /mnt
sudo mount /dev/sdb2 /mnt/boot/efi

sudo grub-install --target=x86_64-efi /dev/sdb --efi-directory=/mnt/boot/efi --boot-directory=/mnt/boot
```





Ubuntu 重新安装 GRUP

检查步骤：
1. 检查 BIOS/UEFI 启动项（进入 BIOS/UEFI 中排查）
2. 检查硬盘引导区（EFI）（使用 Ventoy + GParted Live CD 排查）
3. 检查 GRUB （使用 Ventoy + PVE 安装镜像， 进入 PVE  下边 Rescue 模式排查）`proxmox-boot-tool status`

判断为 GRUB 文件损坏，修复步骤：
1. `lsblk` 列出所有可用块设备的信息
```
NAME                         MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
sda                            8:0    0 465.8G  0 disk
├─sda1                         8:1    0  1007K  0 part
├─sda2                         8:2    0     1G  0 part /boot/efi
└─sda3                         8:3    0 464.8G  0 part
  ├─pve-swap                 252:0    0     8G  0 lvm  [SWAP]
  ├─pve-root                 252:1    0    96G  0 lvm  /
  ├─pve-data_tmeta           252:2    0   3.4G  0 lvm 
  ..........
```
2. `umount /boot/efi`
3. `proxmox-boot-tool init /dev/<p2>  #replace <p2> with whatever you have eg: /dev/sda2 or maybe /dev/nvme0n1p2 etc` 或 `proxmox-boot-tool refresh`
4. 重启

参考：
- https://forum.proxmox.com/threads/stuck-on-welcome-to-grub-after-update.164133/post-758485
- https://pve.proxmox.com/pve-docs/chapter-sysadmin.html#sysboot_proxmox_boot_tool

PVE 启动时，卡在 “Welcome to GRUB!” 界面

### CMake Build
```bash
mkdir build
cd build

cmake .. -DCMAKE_INSTALL_PREFIX=./install/ -G "Visual Studio 17 2022" -A x64

PATH=$PATH:/c/dev/Qt/Tools/mingw810_64/bin/
cmake .. -G "MinGW Makefiles" -DCMAKE_MAKE_PROGRAM=mingw32-make -DCMAKE_INSTALL_PREFIX=./install/

PATH=$PATH:/c/dev/Qt/Tools/mingw810_64/bin/
cmake .. -G "Ninja" -DCMAKE_INSTALL_PREFIX=./install/

cmake --build .
cmake --install .
```

### 判断操作系统
```cmake
IF (CMAKE_SYSTEM_NAME MATCHES "Linux")

ELSEIF (CMAKE_SYSTEM_NAME MATCHES "Windows")

ELSEIF (CMAKE_SYSTEM_NAME MATCHES "FreeBSD")

ELSE ()
MESSAGE(STATUS "other platform: ${CMAKE_SYSTEM_NAME}")
ENDIF (CMAKE_SYSTEM_NAME MATCHES "Linux")
```

```cmake
if(WIN32)
    # todo: windows action
elseif(APPLE)
    # todo: mac action
elseif(UNIX)
    # todo: linux action
endif()
```

### 判断编译器
```cmake
if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
# using Clang
elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
# using GCC
elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Intel")
# using Intel C++
elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
# using Visual Studio C++
endif()
```


CMake 笔记

## 安装 Elastic Stack

> CenOS 7

```shell
rpm --import https://artifacts.elastic.co/GPG-KEY-elasticsearch

# ES 7
cat << EOF > /etc/yum.repos.d/elasticsearch.repo
[elasticsearch]
name=Elasticsearch repository for 7.x packages
baseurl=https://mirrors.tuna.tsinghua.edu.cn/elasticstack/7.x/yum
gpgcheck=1
gpgkey=https://artifacts.elastic.co/GPG-KEY-elasticsearch
enabled=1
autorefresh=1
type=rpm-md
EOF

# ES 8
cat << EOF > /etc/yum.repos.d/elasticsearch.repo
[elasticsearch]
name=Elasticsearch repository for 8.x packages
baseurl=https://mirrors.tuna.tsinghua.edu.cn/elasticstack/8.x/yum
gpgcheck=1
gpgkey=https://artifacts.elastic.co/GPG-KEY-elasticsearch
enabled=1
autorefresh=1
type=rpm-md
EOF

yum install -y elasticsearch kibana logstash

systemctl daemon-reload
systemctl enable elasticsearch.service
systemctl enable kibana.service
systemctl enable logstash.service
```

> Ubuntu

```shell
sudo apt install apt-transport-https
wget -qO - https://artifacts.elastic.co/GPG-KEY-elasticsearch | sudo apt-key add -
# ES 7
echo "deb https://mirrors.tuna.tsinghua.edu.cn/elasticstack/7.x/apt stable main" | sudo tee /etc/apt/sources.list.d/elastic-7.x.list
# ES 8
echo "deb https://mirrors.tuna.tsinghua.edu.cn/elasticstack/8.x/apt stable main" | sudo tee /etc/apt/sources.list.d/elastic-8.x.list
sudo apt update && sudo apt install -y elasticsearch kibana logstash

systemctl daemon-reload
systemctl enable elasticsearch.service
systemctl enable kibana.service
systemctl enable logstash.service
```

## 建立中文索引

> IK Analysis for Elasticsearch

```shell
ES_VERSION=7.6.1 JAVA_HOME=/usr/share/elasticsearch/jdk/ \
/usr/share/elasticsearch/bin/elasticsearch-plugin install \
https://get.infini.cloud/elasticsearch/analysis-ik/$ES_VERSION
```

* 建立 mapping 的时候， 增加 analyzer 属性 IK分词器（ik_max_word / ik_smart）
    * ik_max_word ：会将文本做最细粒度的拆分
    * ik_smart ：会将文本做最粗粒度的拆分

> Pinyin Analysis for Elasticsearch

```shell
ES_VERSION=7.6.1 JAVA_HOME=/usr/share/elasticsearch/jdk/ \
/usr/share/elasticsearch/bin/elasticsearch-plugin install \
https://get.infini.cloud/elasticsearch/analysis-pinyin/$ES_VERSION
```

## 开放外网访问

```shell
cat << EOF >>  /etc/elasticsearch/elasticsearch.yml
network.host: 0.0.0.0
http.port: 9200
discovery.type: single-node
EOF

systemctl restart elasticsearch.service
```

## 遇到的问题

> "Validation Failed: 1: this action would add [2] shards, but this cluster currently has [1903]/[1000] maximum normal shards open;"

```shell
cat << EOF >>  /etc/elasticsearch/elasticsearch.yml
cluster.max_shards_per_node: 10000
EOF

systemctl restart elasticsearch.service
```

> Error enabling rule: could not create API key - feature_not_enabled_exception: [feature_not_enabled_exception] Reason: api keys are not enabled

```bash
cat << EOF >>  /etc/elasticsearch/elasticsearch.yml
xpack.security.authc.api_key.enabled: true
EOF

systemctl restart elasticsearch.service
```


```bash
/usr/share/kibana/bin/kibana-encryption-keys generate

cat << EOF >>  /etc/kibana/kibana.yml
xpack.encryptedSavedObjects.encryptionKey: b9d7e558c8e03ca80e698384189d4751
xpack.reporting.encryptionKey: ca8c1a3551bfba02cf0ffd3dbb0df52b
xpack.security.encryptionKey: d0b8fe87528c2da203ac402bf7d6308c
EOF

systemctl restart kibana.service
```

ElasticStack 笔记

## Java 在加载和卸载动态库

> 当动态库被加载时这个函数被系统调用
```c
JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM *jvm, void *reserved) {
	JNIEnv *env = NULL;
	if ((*jvm)->GetEnv(jvm, (void **) &env, JNI_VERSION_1_4) != JNI_OK)
		return JNI_ERR;
	
	// my code...
	
	return JNI_VERSION_1_4;
}
```

> 当动态库被卸载时这个函数被系统调用
```c
JNIEXPORT void JNI_OnUnload(JavaVM* vm, void* reserved) {
	// my code ...
}
```

## JNI 注册本地函数

1. 通过 FindClass() 查找 Java 中的 class 引用。
```c
jclass clazz = (*env)->FindClass(env, "")
```
2. 通过 RegisterNatives() 注册本地函数。
```c
JNINativeMethod methods[] = {
        {"getText", "()Ljava/lang/String;", getText}
};
(*env)->RegisterNatives(env, clazz, &methods, sizeof(methods)/sizeof((methods)[0]));
```
3. 关于 RegisterNatives() 中的 JNINativeMethod 结构体。
```c
typedef struct {
    const char* name;
    const char* signature;
    void*       fnPtr;
} JNINativeMethod;

// name: 需要注册的 Java 函数名
// signature: 函数参数和返回值类型
// fnPtr: 需要注册的 C 函数指针
```