낭만 상민이의 不老區

안철수,박경철의 대화(다소 볼만함)

(낭만상민) — Thu, 29 Apr 2010 11:29:48 +0900

멍때리고 있을때 한번쯤 봐주세요.
http://blogsabo.ahnlab.com/300

Fedora 11 x-window 가 root 로그인이 안되는 문제 해결.

(낭만상민) — Tue, 13 Oct 2009 09:32:36 +0900

문제라기 보다는 보안상 고의로 막아놓은 설정을 고치는 것이다.
아래의 문서를 읽어 보면 해답을 찾을수 있다.
/etc/pam.d/gdm ,과 /etc/pam.d/gdm-password 두스크립트에서
해당 설정 부분을 지우면 된다.

http://www.labtestproject.com/using_linux/step_by_step_enable_root_login_on_fedora_11_gui_desktop.html

시간 날때 gdm 에 관한 심도있는 이야기를 해볼까 한다.

어느나라 ip인지 알아내는 방법.

(낭만상민) — Tue, 25 Nov 2008 13:28:08 +0900

ip address <-> ip number 전환코드를 찾다가 찾아낸 조금 재미있는 것. ip대역 CSV 파일(GeoIp Country CSV)을 구해야함.
심심하면 함 만들어 보심.

GeoIP Country CSV Text Files

MaxMind GeoIP databases are available in a Comma Separated Value (CSV) format, in addition to the binary format. These CSV files generally contain IP Address range and geographical data for all publicly assigned IPv4 addresses.

Due to the large size of geolocation databases, we generally recommend using our binary format with one of our APIs, since they are highly optimized for speed and disk space. On the other hand, if you have a requirement to import the data into a SQL database, the CSV format is recommended. We have listed some guidelines for importing and querying the data with a SQL database.

CSV Format

The CSV File contains four fields:

* Beginning IP Number*
* Ending IP Number*
* ISO 3166 Country Code
* Country Name

This is an sample of how the CSV file is structured:

"begin_num","end_num","country","name"
"1029177344","1029439487","AU","Australia"
"1029439488","1029570559","HK","Hong Kong"
"1029570560","1029572607","ID","Indonesia"

* Beginning IP Number and Ending IP Number are calculated as follows:

ipnum = 16777216*w + 65536*x + 256*y + z (1)

where

IP Address = w.x.y.z

The reverse of this formula is

w = int ( ipnum / 16777216 ) % 256;
x = int ( ipnum / 65536 ) % 256;
y = int ( ipnum / 256 ) % 256;
z = int ( ipnum ) % 256;

Where % is the mod operator.

Here is sample Perl code to convert the IP number to
a IP address:

sub numToStr {
my ($ipnum) = @_;
my $z = $ipnum % 256;
$ipnum >>= 8;
my $y = $ipnum % 256;
$ipnum >>= 8;
my $x = $ipnum % 256;
$ipnum >>= 8;
my $w = $ipnum % 256;
return "$w.$x.$y.$z";
}

It is useful to have the IP Number if you are performing IP Address lookups using a database. For example the following queries will find the country based on IP Address 24.24.24.24:

SQL Query

SELECT ip_country FROM geoip WHERE 404232216 BETWEEN begin_ip_num AND end_ip_num

MySQL Query

SELECT ip_country FROM geoip WHERE 404232216 >= begin_ip_num AND
　　　404232216 <= end_ip_num

Here we used the formula (1) to compute the IP Number based on 24.24.24.24

404232216 = 16777216*24 + 65536*24 + 256*24 + 24

For more information on importing GeoIP CSV files into MySQL, see HOW-TO Import the MaxMind GeoIP Free Country CSV file into MySQL and save diskspace.

http://www.delau.net/php/geoip.html

Enable Or Disable Extension Loading(SQLITE)

(낭만상민) — Tue, 14 Oct 2008 13:31:16 +0900

Interrupt A Long-Running Query
- 장시간 구동 쿼리 중지
void sqlite3_interrupt(sqlite3*);

This function causes any pending database operation to abort and return at its earliest opportunity.
- 이 함수는 길어지는 database 작업을 중단시켜서 빠른시간안에 다른 작업을 수행할 준비를 할수 있게 해준다.

This routine is typically called in response to a user action such as pressing "Cancel" or Ctrl-C where the user wants a long query operation to halt immediately.
- 이 함수의 역할은 긴 시간이 걸리는 작업에 대해서 "Cancel" 하거나 Ctrl-C 를 통하여 작업 중지 하는 것과 같은 역할을 한다.

It is safe to call this routine from a thread different from the thread that is currently running the database operation.
- 이 함수의 사용은 현재 실행중인 다중 쓰레드의 동시 작업 들에 대해서 안전하다.
But it is not safe to call this routine with a database connection that is closed or might close before sqlite3_interrupt() returns.
- 하지만 sqlite3_interrupt() 가 끝나기 전에 중지된 혹은 중지될 database connection 에 대해서는 안전 하지 않다.

If an SQL operation is very nearly finished at the time when sqlite3_interrupt() is called, then it might not have an opportunity to be interrupted and might continue to completion.
- 만일 sqlite3_interrupt() 가 호출되는 순간 바로 끝나버릴 SQL 작업이있다면 작업의 온전한 중지를 하지 못한다.

An SQL operation that is interrupted will return SQLITE_INTERRUPT.
- 중지된 SQL operation 에 대해서는 SQLITE_INTERRUPT 를 반환한다.

If the interrupted SQL operation is an INSERT, UPDATE, or DELETE that is inside an explicit transaction, then the entire transaction will be rolled back automatically.
- 만일 INSERT,UPDATE,DELETE 명령어 수행중 중지 되었다면 전체 transaction이 자동적으로 Roll back 된다.

A call to sqlite3_interrupt() has no effect on SQL statements that are started after sqlite3_interrupt() returns.
- 시작된후 sqlite3_interrupt() returns 을 받은 SQL 문에 대해서는 sqlite3_interrupt() 함수를 (다시) 호출해도 아무런 영향이 없다.

Invariants:
H12271 The sqlite3_interrupt() interface will force all running SQL statements associated with the same database connection to halt after processing at most one additional row of data.
H12272 Any SQL statement that is interrupted by sqlite3_interrupt() will return SQLITE_INTERRUPT.

Assumptions:
A12279 If the database connection closes while sqlite3_interrupt() is running then bad things will likely happen.

See also lists of Objects, Constants, and Functions.

The hamsterdb Tutorial (http://hamsterdb.com) 번역문서

(낭만상민) — Thu, 4 Sep 2008 21:42:15 +0900

Page 1

The hamsterdb Tutorial
:hamsterdb 강좌

A Tutorial Book for hamsterdb.
:hamsterdb 강좌 자료.

This tutorial is a WORK IN PROGRESS. Do not consider it as a finished document.
:이 강좌 자료는 제작중 입니다. 아직 완료 되지 않은 문서임을 고려해 주세요.

Feedback and comments are always welcome. Please send them to contact@hamsterdb.com.
:의견이나 조언은 contact@hamsterdb.com 로 보내주시고 늘 환영합니다.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU
Free Documentation License, Version 1.1 or any later version published by the Free Software
Foundation; with Invariant Sections being „The GNU Free Documentation License“, with no Front-
Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled
„GNU Free Documentation License“.
:복제 나 배포 혹은 문서 수정은 GNU Free Documentation License (Version 1.1) 혹은 자유소프트웨어재단 에 의해
이후 버전의 License 에 의거하여 허용한다. GNU Free Documentation License 의 Invariant 섹션에 의거하여
앞/뒤 표지의 Text 는 유지 해야 한다. 사본의 모든 권리(권한)는 전적으로 'GNU Free Doumentaion License' 에 의거한다.

-------------------------------------------------
Page 2

Table of Contents
Introduction.........................................................................................................................................3
What is hamsterdb?.........................................................................................................................3
Material Covered............................................................................................................................3
Conventions Used in this Tutorial...................................................................................................3
More Documentation on hamsterdb................................................................................................3
Obtaining the Most Recent Versions...............................................................................................3
hamsterdb Licensing.......................................................................................................................4
Getting Started.....................................................................................................................................4
Building for UNIX/POSIX systems................................................................................................4
Building for Microsoft Windows.....................................................................................................4
Porting hamsterdb to Other Platforms.............................................................................................4
Creating a Database.............................................................................................................................5
Creating an In-Memory Database....................................................................................................6
Creating a Record Number Database...............................................................................................6
Opening a Database.............................................................................................................................7
Changing the Default Key Sorting.......................................................................................................7
Inserting Database Items......................................................................................................................8
Deleting Database Items.......................................................................................................................9
Looking up Database Items..................................................................................................................9
Working with Database Cursors.........................................................................................................10
Creating a Database Cursor...........................................................................................................10
Moving Database Cursors..............................................................................................................11
Inserting Database Items with Cursors..........................................................................................12
Looking up Database Items with Cursors......................................................................................12
Overwriting Database Items with Cursors.....................................................................................13
Deleting Database Items with Cursors...........................................................................................13
Cloning a Database Cursor............................................................................................................13
Closing a Database Cursor.............................................................................................................13
Closing a Database............................................................................................................................13
Working with Database Environments...............................................................................................14
Creating a new Environment.........................................................................................................14
Creating In-Memory Environments..........................................................................................15
Opening an Environment...............................................................................................................15
Creating a Database in an Environment........................................................................................16
Opening a Database in an Environment........................................................................................16
Renaming a Database in an Environment......................................................................................16
Removing a Database from an Environment.................................................................................17
Closing an Environment................................................................................................................17
Working with Duplicate Keys............................................................................................................17
Enabling Duplicate Keys...............................................................................................................17
Inserting Duplicate Keys...............................................................................................................17
Traversing Duplicate Keys............................................................................................................18
Replacing Duplicate Keys.............................................................................................................18
Get the Number of Duplicate Keys................................................................................................18
Deleting Duplicate Keys................................................................................................................19
The C++ API.....................................................................................................................................19
Appendix I: The GNU General Public License 2.0............................................................................20
Appendix II: The GNU General Public License 3.0..........................................................................24
Appendix III: The GNU Free Documentation License......................................................................35