Permission denied when trying to install gcc, even if logged as root - gcc

Question

I'm trying to install gcc 4.7.0 on ubuntu 10.04 following that tutorial http://www.tellurian.com.au/whitepapers/multiplegcc.php. After some time to install the dependencies, I've been able to run make without errors, but the final step, make install doesn't want to succeed, it end up with permission denied.
Here's what I did :
../gcc-4.7.0/configure --prefix=/usr/local/gcc/4.7.7 --enable-languages=c,c++
make
su -l
cd /groups/gobj
make install
the result for the last command :
make[1]: Entering directory `/groups/gobj'
/bin/bash ../gcc-4.7.0/mkinstalldirs /usr/local/gcc/4.7.7 /usr/local/gcc/4.7.7
make[2]: Entering directory `/groups/gobj/fixincludes'
rm -rf /usr/local/gcc/4.7.7/libexec/gcc/x86_64-unknown-linux-gnu/4.7.0/install-tools
/bin/bash ../../gcc-4.7.0/fixincludes/../mkinstalldirs /usr/local/gcc/4.7.7/libexec
...
rm -f /usr/local/gcc/4.7.7/share/info/gccinstall.info
if [ -f doc/gccinstall.info ]; then \
for f in doc/gccinstall.info*; do \
realfile=`echo $f | sed -e 's|.*/\([^/]*\)$|\1|'`; \
/usr/bin/install -c -m 644 $f /usr/local/gcc/4.7.7/share/info/$realfile; \
chmod a-x /usr/local/gcc/4.7.7/share/info/$realfile; \
done; \
else true; fi
if /bin/bash -c 'install-info --version' >/dev/null 2>&1; then \
if [ -f /usr/local/gcc/4.7.7/share/info/gccinstall.info ]; then \
install-info --dir-file=/usr/local/gcc/4.7.7/share/info/dir /usr/local/gcc/4.7.7/share/info/gccinstall.info; \
else true; fi; \
else true; fi;
build/genhooks -d \
../../gcc-4.7.0/gcc/doc/tm.texi.in > tmp-tm.texi
/bin/bash: tmp-tm.texi: Permission denied
make[2]: *** [s-tm-texi] Error 1
make[2]: Leaving directory `/groups/gobj/gcc'
make[1]: *** [install-gcc] Error 2
make[1]: Leaving directory `/groups/gobj'
make: *** [install] Error 2
I've already tried su root, su -, su without succes. Some files are effectively copied to /usr/local/gcc/4.7.0 but the process stopped and I don't understand why as I'm logged as root. I've checked, the file /groups/gcc-4.7.0/gcc/doc/tm.texi.in exists. Any help ?

Answer 1

As puzzling as it sounds that the superuser "root" cannot create files while a normal user can, a likely scenario is that your build directory (that is, the directory in which you ran "make install") is being served from an NFS server, and it is probably mounted such that the server doesn't trust your build machine's request to write files as root.
As a simple test see if you can write an empty file to the build directory by running touch test as root. If that fails then you've found the source of the problem. Another way to confirm it is to check the output of "mount" at at least confirm that your build directory is being served via NFS.
server:/groups 20G 948M 19G 5% /groups
If you see a line like this in the mount output then you know for certain that your build directory is being NFS mounted. To tell whether or not root is being trusted, however, you'll ultimately have to check the settings on the NFS server.
Fixing the problem
The fastest way to fix this issue is to find a local filesystem on your build machine and move the contents of your build directory there, then re-run "make install".

Answer 2

Did you tried sudo?
sudo make install
Edit:
As root, you can add yourself to sudoers.
If you can't get root via sudo, try either
su - root
or
ssh root#...