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How to set coredump file path

January 21, 2023 · One min read

Get coredump file path

$ sysctl kernel.core_pattern

Set coredump file path

$ sysctl -w kernel.core_pattern=/var/crash/core.%u.%p.%t

How to associate assembly code to exact line in C program?

January 15, 2023 · One min read

gcc arguments

gcc -fverbose-asm

objdump arguments

objdump -lSd

Useful Macro that can be a template

January 14, 2023 · One min read

#define SYSCALL_DEFINE(name) static inline long SYSC_##name
#define SYSCALL_DEFINE0(name)	   asmlinkage long sys_##name(void)
#define SYSCALL_DEFINE1(name, ...) SYSCALL_DEFINEx(1, _##name, __VA_ARGS__)
#define SYSCALL_DEFINE2(name, ...) SYSCALL_DEFINEx(2, _##name, __VA_ARGS__)
#define SYSCALL_DEFINE3(name, ...) SYSCALL_DEFINEx(3, _##name, __VA_ARGS__)
#define SYSCALL_DEFINE4(name, ...) SYSCALL_DEFINEx(4, _##name, __VA_ARGS__)
#define SYSCALL_DEFINE5(name, ...) SYSCALL_DEFINEx(5, _##name, __VA_ARGS__)
#define SYSCALL_DEFINE6(name, ...) SYSCALL_DEFINEx(6, _##name, __VA_ARGS__)


/*
 * Example
 */

/**
 * sys_sched_setparam - set/change the RT priority of a thread
 * @pid: the pid in question.
 * @param: structure containing the new RT priority.
 */
SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
{
	return do_sched_setscheduler(pid, -1, param);
}

#define SYSCALL_DEFINE(name) static inline long SYSC_##name
#define SYSCALL_DEFINE0(name)	   asmlinkage long sys_##name(void)
#define SYSCALL_DEFINE1(name, ...) SYSCALL_DEFINEx(1, _##name, __VA_ARGS__)
#define SYSCALL_DEFINE2(name, ...) SYSCALL_DEFINEx(2, _##name, __VA_ARGS__)
#define SYSCALL_DEFINE3(name, ...) SYSCALL_DEFINEx(3, _##name, __VA_ARGS__)
#define SYSCALL_DEFINE4(name, ...) SYSCALL_DEFINEx(4, _##name, __VA_ARGS__)
#define SYSCALL_DEFINE5(name, ...) SYSCALL_DEFINEx(5, _##name, __VA_ARGS__)
#define SYSCALL_DEFINE6(name, ...) SYSCALL_DEFINEx(6, _##name, __VA_ARGS__)


/*
 * Example
 */

/**
 * sys_sched_setparam - set/change the RT priority of a thread
 * @pid: the pid in question.
 * @param: structure containing the new RT priority.
 */
SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
{
	return do_sched_setscheduler(pid, -1, param);
}

How to copy to clipboard in Vim?

January 11, 2023 · One min read

Requirements

$ vim --version | grep clipboard

+clipboard         +keymap            +printer           +vertsplit
+eval              -mouse_jsbterm     -sun_workshop      +xterm_clipboard

if clipboard is -, then we need install vim-gtk.

for example, on ubuntu:

$ sudo apt install -y vim-gtk

Settings

vim ~/.vimrc

On macOS and Windows set:

$ set clipboard=unnamed

On Linux set (vim 7.3.74+):

$ set clipboard=unnamedplus

Configure Local NTP Server

January 9, 2023 · One min read

install NTP package

# CentOS
$ sudo yum install -y ntp

# Ubuntu
$ sudo apt install -y ntp

Edit ntp.conf

$ vim /etc/ntp.conf

# Add local server
server 192.168.5.104

# Set access restrict
restrict 192.168.5.0 mask 255.255.254.0 notrap

# Set logfile
logfile /var/log/ntpservice.log

Start NTP server

$ ntpd

Verify NTP Server

$ ntpq -p

Connection ‘ens33‘ is not available on device ens33 because device is strictly unmanaged

December 20, 2022 · 2 min read

虚拟机开启 ifconfig 没有ens33网卡，无法上网，同时图形化模式没有有线连接选项，重启NetworkManager没有用

connection ‘ens33‘ is not available on device ens33 because device is strictly unmanaged

查看托管状态

$ nmcli
docker0: disconnected
        "docker0"
        bridge, 02:42:74:81:0C:62, sw, mtu 1500

ens33: unmanaged
        "Intel 82545EM"
        ethernet (e1000), 00:0C:29:C7:13:F3, hw, mtu 1500

lo: unmanaged
        "lo"
        loopback (unknown), 00:00:00:00:00:00, sw, mtu 65536

Use "nmcli device show" to get complete information about known devices and
"nmcli connection show" to get an overview on active connection profiles.

Consult nmcli(1) and nmcli-examples(7) manual pages for complete usage details.

开启托管

$ nmcli n on

$  nmcli
docker0: disconnected
        "docker0"
        bridge, 02:42:74:81:0C:62, sw, mtu 1500

ens33: unmanaged
        "Intel 82545EM"
        ethernet (e1000), 00:0C:29:C7:13:F3, hw, mtu 1500

lo: unmanaged
        "lo"
        loopback (unknown), 00:00:00:00:00:00, sw, mtu 65536

Use "nmcli device show" to get complete information about known devices and
"nmcli connection show" to get an overview on active connection profiles.

Consult nmcli(1) and nmcli-examples(7) manual pages for complete usage details.

reference

Connection ‘ens33‘ is not available on device ens33 because device is strictly unmanaged_victoruu的博客-CSDN博客_device is strictly

docker modify config for running container

December 16, 2022 · One min read

here is mounted directory

stop docker

$ systemctl stop docker

modify container's config

$ cd /var/lib/docker/container/$containerID/

$ vim config.v2.json

# modify MountPoints

$ vim hsotconfig.json

# modify Binds

start docker

$ systemctl start docker

start container

$ docker start $containerID

Set up Meld as Difftool and Mergetool for Git

November 22, 2022 · One min read

Configure Meld as Default Git Tools

Edit Config File

.gitconfig

[merge]
    tool = meld
[mergetool "meld"]
    # Choose one of these 2 lines
    cmd = meld "$LOCAL" "$MERGED" "$REMOTE" --output "$MERGED"
    cmd = meld "$LOCAL" "$BASE" "$REMOTE" --output "$MERGED"

Commands for Windows and Linux

for Windows

$ git config --global diff.tool meld
$ git config --global difftool.meld.path "C:\Program Files (x86)\Meld\Meld.exe"
$ git config --global difftool.prompt false

$ git config --global merge.tool meld
$ git config --global mergetool.meld.path "C:\Program Files (x86)\Meld\Meld.exe"
$ git config --global mergetool.prompt false

For Linux

$ git config --global diff.tool meld
$ git config --global difftool.meld.path "C:\Program Files (x86)\Meld\Meld.exe"
$ git config --global difftool.prompt false

$ git config --global merge.tool meld
$ git config --global mergetool.meld.path "C:\Program Files (x86)\Meld\Meld.exe"
$ git config --global mergetool.prompt false

gdb show list

November 8, 2022 · One min read

print list in GDB

define phead
    set $ptr = $arg1
    plistdata $arg0
end

document phead
Print the first element of a list. E.g., given the declaration
    Glist *datalist;
    g_list_add(datalist, "Hello");
view the list with something like
gdb> phead char datalist
gdb> pnext char
gdb> pnext char

This macro defines $ptr as the current pointed-to list struct,
and $pdata as the data in that list element.
end

define pnext
    set $ptr = $ptr->next
    plistdata $arg0
end

document pnext
You need to call phead first; that will set $ptr.
This macro will step forward in the list, then show the value at
that next element. Give the type of the list data as the only argument.

This macro defines $ptr as the current pointed-to list struct, and
$pdata as the data in that list element.
end

insecurity proof failed resolving '$DOMAIN/A/IN'

October 28, 2022 · One min read

dns forward failed

Error message:

28-Oct-2022 09:49:09.251 managed-keys-zone: Key 20326 for zone . is now trusted (acceptance timer complete)
28-Oct-2022 09:49:09.490 resolver priming query complete: success
28-Oct-2022 09:49:14.088 chase DS servers resolving 'bdc500.com/DS/IN': 192.168.5.104#53
28-Oct-2022 09:49:15.003 insecurity proof failed resolving 'bdc500.com/A/IN': 192.168.5.104#53
28-Oct-2022 09:50:46.782 connection refused resolving 'bdc500.com/A/IN': 192.168.5.104#53
28-Oct-2022 09:50:51.070 validating bdc500.com/A: got insecure response; parent indicates it should be secure
28-Oct-2022 09:50:51.070 insecurity proof failed resolving 'bdc500.com/A/IN': 192.168.5.104#53

Solution

it is because dnssec without key, the simpliest way is :

dnssec-validation no;

reference
- Trust Anchors

Get coredump file path​

Set coredump file path​

Requirements​

Settings​

here is mounted directory​

Configure Meld as Default Git Tools​

Edit Config File​

Commands for Windows and Linux​

print list in GDB​

dns forward failed​