bgpd crash on start if -d flag and frr.conf is missing

[IvayloJ]

Description

If frr.conf is missing and bgpd is started with -d flag (daemon mode) the bgpd process crash.

Version

All versions from 10.1 to master. And all packages from deb.frrouting.org

How to reproduce

bgpd -f /etc/frr/bgpd.conf -F traditional -u frr -g frr -A 127.0.0.1 -d

/home/frr/frr-master/install/lib/frr/bgpd -v
bgpd version 10.4-dev
Copyright 1996-2005 Kunihiro Ishiguro, et al.
configured with:
'--build=x86_64-linux-gnu' '--prefix=/home/frr/frr-master/install' '--localstatedir=/home/frr/frr-master/install/var' '--localstatedir=/home/frr/frr-master/install/frr' '--sbindir=/home/frr/frr-master/install/lib/frr' '--libdir=/home/frr/frr-master/install/lib/x86_64-linux-gnu/frr' '--with-moduledir=/home/frr/frr-master/install/lib/frr/modules' '--sysconfdir=/etc' '--disable-option-checking' '--disable-silent-rules' '--disable-maintainer-mode' '--with-vtysh-pager=/usr/bin/pager' '--disable-dependency-tracking' '--disable-scripting' '--enable-rpki' '--disable-pim6d' '--with-libpam' '--enable-snmp' '--enable-fpm' '--disable-protobuf' '--disable-zeromq' '--enable-ospfapi' '--enable-bgp-vnc' '--enable-multipath=256' '--enable-user=frr' '--enable-group=frr' '--enable-vty-group=frrvty' '--enable-configfile-mask=0640' '--enable-logfile-mask=0640' 'build_alias=x86_64-linux-gnu' 'PYTHON=python3'

Expected behavior

bgpd to not crash

Actual behavior

bgpd crash

Additional context

BGP: Received signal 11 at 1740844575 (si_addr 0x0, PC 0x7f94cb6d807d); aborting
...
BGP: /home/frr/frr-master/install/lib/x86_64-linux-gnu/frr/libfrr.so.0(zlog_back
trace_sigsafe+0x5e) [0x7f94cbbd0a1e]
BGP: /home/frr/frr-master/install/lib/x86_64-linux-gnu/frr/libfrr.so.0(zlog_sign
al+0xe4) [0x7f94cbbd0bf4]
BGP: /home/frr/frr-master/install/lib/x86_64-linux-gnu/frr/libfrr.so.0(+0x107782) [0x7f94cbc0c782]
BGP: /lib/x86_64-linux-gnu/libpthread.so.0(+0x12730) [0x7f94cb808730]
BGP: /lib/x86_64-linux-gnu/libc.so.6(+0xa207d) [0x7f94cb6d807d]
BGP: /lib/x86_64-linux-gnu/libc.so.6(_IO_getline_info+0x124) [0x7f94cb6a70f4]
BGP: /lib/x86_64-linux-gnu/libc.so.6(fgets+0xab) [0x7f94cb6a611b]
BGP: /home/frr/frr-master/install/lib/x86_64-linux-gnu/frr/libfrr.so.0(config_from_file+0x3d) [0x7f94cbba0cbd]
BGP: /home/frr/frr-master/install/lib/x86_64-linux-gnu/frr/libfrr.so.0(vty_read_file+0x59) [0x7f94cbc273e9]
BGP: /home/frr/frr-master/install/lib/x86_64-linux-gnu/frr/libfrr.so.0(vty_read_config+0x2a) [0x7f94cbc2744a]
BGP: /home/frr/frr-master/install/lib/x86_64-linux-gnu/frr/libfrr.so.0(+0xc2b9c) [0x7f94cbbc7b9c]
BGP: /home/frr/frr-master/install/lib/x86_64-linux-gnu/frr/libfrr.so.0(event_call+0xa1) [0x7f94cbc1e271]
BGP: /home/frr/frr-master/install/lib/x86_64-linux-gnu/frr/libfrr.so.0(frr_run+0xb8) [0x7f94cbbc80c8]
BGP: /home/frr/frr-master/install/lib/frr/bgpd(main+0x444) [0x55830508c8f4]
BGP: /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xeb) [0x7f94cb65a09b]
BGP: /home/frr/frr-master/install/lib/frr/bgpd(_start+0x2a) [0x55830508eeba]
BGP: in thread frr_config_read_in scheduled from lib/libfrr.c:1054 frr_config_fork()

Checklist

• I have searched the open issues for this bug.
• I have not included sensitive information in this report.

[ton31337]

# ls -a /etc/frr/frr.conf /etc/frr/bgpd.conf
ls: cannot access '/etc/frr/frr.conf': No such file or directory
ls: cannot access '/etc/frr/bgpd.conf': No such file or directory

# /usr/lib/frr/bgpd -f /etc/frr/bgpd.conf -F traditional -u frr -g frr -A 127.0.0.1 -d
# ps aufx | grep bgpd                                                                      
frr      12935  0.0  0.0 216012 11580 ?        Ssl  23:10   0:00 /usr/lib/frr/bgpd -f /etc/frr/bgpd.conf -F traditional -u frr -g frr -A 127.0.0.1 -d

What am I missing?