Problems with syscalls

[Stefano Avola]

Dear Gramine Team,
I'm a PhD student of the University of Genoa (Italy) and I'm working on
projects involving Gramine. Currently, I'm trying to graminize (via also
GSC) an open-source system developed in GoLang and I have encountered in
some problems as reported below:

1) when I call `os.Rename()` what I receive is `Error: filesystem error:
cannot rename: Function not implemented`, but I found that both `rename`
and `renameat` syscalls are implemented in the source code of Gramine
(https://github.com/gramineproject/gramine/blob/master/libos/src/sys/libos_file.c#L355
and
https://github.com/gramineproject/gramine/blob/master/libos/src/arch/x86_64/libos_table.c#L99
and
https://github.com/gramineproject/gramine/blob/master/libos/src/arch/x86_64/libos_table.c#L281).

2) when I call `syscall.NetlinkRIB()` I get route `netlinkrib: address
family not supported by protocol`.

Thus, in both cases I kindly ask you what you suggest me to do in place
of change the source code of the system.
I'm using Gramine (and GSC) v1.8 and I have an Intel i7-9700 CPU and
using an Ubuntu desktop 22.04 with the following SGX features:
```
SGX supported by CPU: true
SGX1 (ECREATE, EENTER, ...): true
SGX2 (EAUG, EACCEPT, EMODPR, ...): false
Flexible Launch Control (IA32_SGXPUBKEYHASH{0..3} MSRs): true
SGX extensions for virtualizers (EINCVIRTCHILD, EDECVIRTCHILD,
ESETCONTEXT): false
Extensions for concurrent memory management (ETRACKC, ELDBC, ELDUC,
ERDINFO): false
EDECCSSA instruction: true
CET enclave attributes support (See Table 37-5 in the SDM): false
Key separation and sharing (KSS) support (CONFIGID, CONFIGSVN,
ISVEXTPRODID, ISVFAMILYID report fields): false
AEX-Notify: true
Max enclave size (32-bit): 0x80000000
Max enclave size (64-bit): 0x1000000000
EPC size: 0x5d80000
SGX driver loaded: true
AESMD installed: true
SGX PSW/libsgx installed: true
#PF/#GP information in EXINFO in MISC region of SSA supported: false
#CP information in EXINFO in MISC region of SSA supported: false
```
Thank you very much,
Best regards,
Stefano Avola

[Michał Kowalczyk]

Those errors mean that your program/library you use/Go runtime uses some
functionality which is not implemented in Gramine. Please check
https://gramine.readthedocs.io/en/stable/devel/features.html.