Date: Wed, 10 Aug 2016 09:44:21 +0900 From: =?UTF-8?B?5bKh6YOoIOWLneW5uA==?= <HGC02147@nifty.com> To: freebsd-users-jp@freebsd.org Subject: [FreeBSD-users-jp 95919] Re: =?utf-8?b?TERfUFJFTE9BRCDjgYzjgYbjgb7jgY/jgYTjgYvjgarjgYQ=?= Message-ID: <d5013ed9-cdaf-c8a2-2fca-8ade8d334207@nifty.com> In-Reply-To: <20160807030939.GA24330@ns.ribbon.or.jp> References: <20160807030939.GA24330@ns.ribbon.or.jp>
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$B2,It$G$9!#(B
9.3-RELEASE$B$G$O$J$/(B10.3-STABLE$B$G$9$,!"(BLD_PRELOAD$B$N@_DjH?1G$5$l$^$9$h!#(B
$B%=!<%9$NJ}$KDV$j4V0c$(Ey$"$j$^$;$s$+!)(B
$B0J2<!";n$7$?FbMF$G$9!#(B
> % cat random_num.c
> #include <stdio.h>
> #include <stdlib.h>
> #include <time.h>
>
> int
> main(int argc, char **argv)
> {
> srand(time(NULL));
> int i = 10;
> while (i--)
> printf("%d\n", rand());
> return 0;
> }
>
> % cc -o random_num random_num.c
> % ./random_num
> 2016130939
> 2115726213
> 976251671
> 1086788223
> 1301263032
> 354334582
> 329183349
> 666688777
> 1616105446
> 511080472
> % cat unrandom.c
> #include <stdlib.h>
>
> int
> rand(void)
> {
> return 42;
> }
>
> % cc -shared -fPIC -o unrandom.so unrandom.c
> % LD_PRELOAD=./unrandom.so ./random_num
> 42
> 42
> 42
> 42
> 42
> 42
> 42
> 42
> 42
> 42
> % LD_PRELOAD=./unrandom.so ldd ./random_num
> ./random_num:
> libc.so.7 => /lib/libc.so.7 (0x800a21000)
> %
----
$B2,It(B $B>!9,(B
On 2016/08/07 12:09, User Ribbon wrote:
> $B<B9T;~$KF0E*%i%$%V%i%j$r:9$7BX$($k<jCJ$H$7$F!"(BLD_PRELOAD $B4D6-JQ?t(B
> $B$,$"$j$^$9!#;HMQNc$H$7$F$O!"(B
>
> https://siguniang.wordpress.com/2015/05/15/override-functions-with-ld_preload/
>
> $B$J$I$,$"$j$^$9!#(B
> FreeBSD$B$G$bF0$/$H;W$C$F$F%9%H$7$F$_$?$N$G$9$,F0$-$^$;$s$G$7$?!#(B
>
> $B>e5-(BURL$B$K$"$k%5%s%W%k%W%m%0%i%`$r;H$$!"(B
>
> setenv LD_PRELOAD ./unrandom.so
>
> $B$r$7$?$"$H!"(B
> %ldd random_num
> $B$H$7$F$b!"(B
> random_num:
> libc.so.7 => /lib/libc.so.7 (0x800a1b000)
>
> $B$H$J$j!"(BLD_PRELOAD $B$7$?7k2L$,H?1G$5$l$^$;$s!#(B
> $BF0:n4D6-$O(B
> FreeBSD bsd09-64 9.3-RELEASE-p43 FreeBSD 9.3-RELEASE-p43 #0: Sat May 28 00:19:32 UTC 2016
> $B$G$9!#(B
>
> $B2?$+$[$+$K@_Dj$7$J$$$HF0$+$J$$$N$G$7$g$&$+!#(B
>
> ribbon
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