[pacman-dev] How does pacman interact with a package's INSTALL script

[Andrew Fyfe]

lordbad wrote:
> In the documentation I have read the following:
> 
>     There are also install files. This PKGBUILD specifies 'foo.install' as the
> package's install file. Here is an example install file:
> 
>     post_install() {
>     /bin/true
>     }
> 
>     post_upgrade() {
>     /bin/true
>     }
> 
>     pre_remove() {
>     /bin/true
>     }
> 
>     op=$1
>     shift
> 
>     $op "$@"
> 
>     Here are the function explainations :
> 
>         * post_install : this script is run right after files are installed, it
> takes one argument :
>               o the package version
>         * post_upgrade : this script is run after all files have been upgraded,
> it takes two arguments :
>               o the new package version
>               o the old package version
>         * pre_remove : this script is run right before files are removed (stop a
> daemon for example) and takes one argument :
>               o the package version
> 
>     The three lines at the bottom are needed in every install file so that they
> run properly.
> 
> But I do not understand how does pacman handle these scripts. Does it source the
> scripts first and then call the shell functions defined in them with some C
> function like "system" for example? But if it does so why are the last 3 lines
> needed - I see little if any need for them. So if anyone can give me some hints
> on the subject and maybe even mention which of pacman's source files implements
> this functionality I'd be very grateful. Thanks in advance for your help.
> 
> Best Regards,
> Bozhidar
> 
> 
> _____________________
> http://www.e-card.bg/
> 
> 
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The function your looking for is _alpm_runscriptlet() 
(lib/libalpm/trans.c:567)

http://projects.archlinux.org/git/?p=pacman.git;a=blob;f=lib/libalpm/trans.c;hb=HEAD#l567

Pacman runs 'source <path to file>/.INSTALL <function name> <old ver> 
<new ver>', the last 3 lines of .INSTALL are needed to get the function 
name and call it.

Andrew