[gentoo-user] OT? How to capture error messages from glibc

[gentoo-user] OT? How to capture error messages from glibc

[Kevin O'Gorman]

[-- Attachment #1: Type: text/plain, Size: 1114 bytes --]

This may be OT, inasmuch as it's not gentoo-specific.  It's here because my
system runs Gentoo and I don't know where else to ask.  If it annoys, just
point me in the right direction to where it will not be OT, please.

I'm trying to write scripts to help me grade student submissions in a
systems programming course.  Students are just learning about malloc/free
and some are floundering.  I'm seeing lots of errors that are caught by
glibc (with some help from compiling with -D_FORTIFY_SOURCE=2), but I would
like instead to capture those messages in a file.  It appears that glibc
does not use stdin or stderr for these messages, since I cannot redirect
them.  I suspect they are being sent to /dev/tty.

Is there any wizardry that would allow capture of these messages?  I know
that somehow the script(1) command captures such stuff, but it's not useable
since I want all of this scripted and ironically script(1) does not seem to
play nice with scripts.  I also know that this is about to tip me into the
abyss of session leaders and controlling terminals, but I'll try to be
brave.

-- 
Kevin O'Gorman, PhD

[-- Attachment #2: Type: text/html, Size: 1194 bytes --]

Re: [gentoo-user] OT? How to capture error messages from glibc

[Alan McKinnon]

On Sunday 18 October 2009 16:06:38 Kevin O'Gorman wrote:
> This may be OT, inasmuch as it's not gentoo-specific.  It's here because my
> system runs Gentoo and I don't know where else to ask.  If it annoys, just
> point me in the right direction to where it will not be OT, please.
> 
> I'm trying to write scripts to help me grade student submissions in a
> systems programming course.  Students are just learning about malloc/free
> and some are floundering.  I'm seeing lots of errors that are caught by
> glibc (with some help from compiling with -D_FORTIFY_SOURCE=2), but I would
> like instead to capture those messages in a file.  It appears that glibc
> does not use stdin or stderr for these messages, since I cannot redirect
> them.  I suspect they are being sent to /dev/tty.
> 
> Is there any wizardry that would allow capture of these messages?  I know
> that somehow the script(1) command captures such stuff, but it's not
>  useable since I want all of this scripted and ironically script(1) does
>  not seem to play nice with scripts.  I also know that this is about to tip
>  me into the abyss of session leaders and controlling terminals, but I'll
>  try to be brave.


My first thought was way out on left field:

could you use syslog-ng to read /dev/tty?

-- 
alan dot mckinnon at gmail dot com