Re: BUG

[Aharon Robbins]

Greetings. Re: this:

> Date: Mon, 29 Mar 2004 15:51:39 +0300 (EEST)
> From: Vladimir Yackusha <address@hidden>
> To: address@hidden
> Subject: BUG
>
> Hi.
> I use Linux Slackware 9.1 with glibc-2.3.2, bash-2.05b, gawk-3.1.3.
>
> While compiling kernel I'm receiving next error:
> address@hidden:/usr/src/linux# make menuconfig
> rm -f include/asm
> ( cd include ; ln -sf asm-i386 asm)
> make -C scripts/lxdialog all
> make[1]: Entering directory `/usr/src/linux-2.4.25/scripts/lxdialog'
> make[1]: Leaving directory `/usr/src/linux-2.4.25/scripts/lxdialog'
> /bin/sh scripts/Menuconfig arch/i386/config.in
> Using defaults found in arch/i386/defconfig
> Preparing scripts: functions, parsingscripts/Menuconfig: line 1433: 18073
> Segmentation fault      awk "$1"
> Awk died with error code 139. Giving up.
>
> I made very simple script, which repeats the error.
> This is the script:
> address@hidden:~/crush# cat Menuconfig
> #!/bin/sh
> function callawk () {
> awk "$1" || { echo "Awk died with error code $?. Giving up."; exit 1; }
> }
> function parser2()
> {
> callawk '
> BEGIN {
>         parser("'config.in'","MCmenu0","1")
> }
> function parser(ifile,menu,num) {
>         if (num > 0) {
>                 system("sleep 10")
>         }
>         while (getline < ifile) {
>                 if ($1 == "source") {
>                         parser($2,menu,"0")
>                 }
>         }
> }'
> }
> parser2
> ---
> In result of running gawk with this script I received the same error:
>
> address@hidden:~/crush# sh Menuconfig
> Menuconfig: line 26: 18103 Segmentation fault      awk "$1"
> Awk died with error code 139. Giving up.
> ---------
> File config.in contains:
> address@hidden:~/crush# cat config.in
>
> asdasdasdasdasdasdasdd
> source test/1.txt
>
>
> address@hidden:~/crush#
> ---------
> This is the test file(config.in) for repeating the error.
>
> File 1.txt in directory "test" does not exist.
>
> If file 1.txt is present in directory "test" this error does not appear.
> File 1.txt may be either empty or not.

This is an old, old, Old, OLD, O L D, *O*L*D* bug in the Menuconfig
script.  I have tried to report it before, but apparently without
success.

If you change the while loop in parser to be:

        while ((getline < ifile) > 0) {

it will work OK. What happens is that getline fails to open the
non-existant file.  This returns -1, which is "true" for the
while loop.  Thus gawk makes another recursive call to parser.
Gawk eventually dies due to infinite recursion.

So, it's not a gawk bug, but rather a logic error in the awk script.

Arnold