'cannot open shared object file' with OpenOnload - linux

Question

I have built and installed https://github.com/Xilinx-CNS/onload shared lib.
Then I am trying:
onload ping 8.8.8.8
Got this error:
ERROR: ld.so: object 'libonload.so' from LD_PRELOAD cannot be preloaded (cannot open shared object file): ignored.
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data. 64 bytes from 8.8.8.8: icmp_seq=1 ttl=110 time=29.2 ms
But it works with sudo onload ping 8.8.8.8:
oo:ping[724989]: netif_tcp_helper_alloc_u: ENODEV. This error can occur if:
- no Solarflare network interfaces are active/UP, or they are running packed stream firmware or are disabled, and
- there are no AF_XDP interfaces registered with sfc_resource Please check your configuration.
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data. 64 bytes from 8.8.8.8: icmp_seq=1 ttl=110 time=50.4 ms
Can someone help me, how I can achieve this command working without sudo? For example, onload nc -l $PORT works without sudo, but ping do not.
Some debug information:
sudo find / -name libonload.so:
/usr/lib/x86_64-linux-gnu/libonload.so
cat /etc/ld.so.conf
include /etc/ld.so.conf.d/*.conf
cat /etc/ld.so.conf.d/*.conf
/usr/lib/x86_64-linux-gnu/libfakeroot
/usr/local/lib
/usr/local/lib/x86_64-linux-gnu
/lib/x86_64-linux-gnu
/usr/lib/x86_64-linux-gnu
/lib32
/usr/lib32
sudo ldconfig -v:
...
/usr/lib/x86_64-linux-gnu/libfakeroot:
libfakeroot-0.so -> libfakeroot-tcp.so
/usr/local/lib:
/lib/x86_64-linux-gnu:
...
libonload_ext.so.2 -> libonload_ext.so.2.0.0
libonload.so -> libonload.so
...
...
ls -l /usr/lib/x86_64-linux-gnu | grep onload
-rwxr-xr-x 1 root root 9528312 Mar 3 01:17 libonload.so
-rw-r--r-- 1 root root 106222 Mar 3 01:17 libonload_ext.a
lrwxrwxrwx 1 root root 18 Mar 3 01:17 libonload_ext.so -> libonload_ext.so.2
lrwxrwxrwx 1 root root 22 Mar 3 01:17 libonload_ext.so.2 -> libonload_ext.so.2.0.0
-rwxr-xr-x 1 root root 31344 Mar 3 01:17 libonload_ext.so.2.0.0
ls -l /lib/x86_64-linux-gnu | grep onload
-rwxr-xr-x 1 root root 9528312 Mar 3 01:17 libonload.so
-rw-r--r-- 1 root root 106222 Mar 3 01:17 libonload_ext.a
lrwxrwxrwx 1 root root 18 Mar 3 01:17 libonload_ext.so -> libonload_ext.so.2
lrwxrwxrwx 1 root root 22 Mar 3 01:17 libonload_ext.so.2 -> libonload_ext.so.2.0.0
-rwxr-xr-x 1 root root 31344 Mar 3 01:17 libonload_ext.so.2.0.0
/lib$ ls -l | grep x86_64-linux-gnu
drwxr-xr-x 35 root root 36864 Mar 3 01:17 x86_64-linux-gnu
/usr/lib$ ls -l | grep x86_64-linux-gnu
drwxr-xr-x 35 root root 36864 Mar 3 01:17 x86_64-linux-gnu

Answer 1

The most likely reason is the ping application uses setuid but the Onload library isn't installed with that. Running ping will effectively promote the application to root user to allow the creation of a raw socket but the library will be loaded as the regular user and so it can't be used. Running as the root user avoids this since the library is loaded as the root user to start with.
I don't think GitHub version of Onload supports loading with setuid for the Onload library but you can set this yourself using chmod +s <libpath>. It's worth pointing out that ping isn't accelerated by Onload since the library will only accelerate UDP and TCP socket and pipes so you wouldn't see any benefit from this.