报错信息如下：

2021/07/23 13:33:43 ...s/graceful/server.go:88:ListenAndServe() [E] Unable to GetListener: listen tcp 0.0.0.0:80: bind: permission denied
2021/07/23 13:33:43 cmd/web.go:235:listen() [C] Failed to start server: listen tcp 0.0.0.0:80: bind: permission denied

解决办法：

setcap cap_net_bind_service=+eip /home/git/gitea/gitea

systemd配置文件：

[root@localhost ~]# cat /etc/systemd/system/gitea.service 
[Unit]
Description=Gitea (Git with a cup of tea)
After=syslog.target
After=network.target

[Service]
# Modify these two values and uncomment them if you have
# repos with lots of files and get an HTTP error 500 because
# of that
#LimitMEMLOCK=infinity
#LimitNOFILE=65535
RestartSec=2s
Type=simple
User=root
Group=root
WorkingDirectory=/home/gitea
# If using Unix socket: tells systemd to create the /run/gitea folder, which will contain the gitea.sock file
# (manually creating /run/gitea doesn't work, because it would not persist across reboots)
#RuntimeDirectory=gitea
ExecStart=/home/gitea/gitea web --port 80
Restart=always
Environment=USER=root HOME=/home/gitea
# GITEA_WORK_DIR=/var/lib/gitea
# If you install Git to directory prefix other than default PATH (which happens
# for example if you install other versions of Git side-to-side with
# distribution version), uncomment below line and add that prefix to PATH
# Don't forget to place git-lfs binary on the PATH below if you want to enable
# Git LFS support
#Environment=PATH=/path/to/git/bin:/bin:/sbin:/usr/bin:/usr/sbin
# If you want to bind Gitea to a port below 1024, uncomment
# the two values below, or use socket activation to pass Gitea its ports as above
###
#CapabilityBoundingSet=CAP_NET_BIND_SERVICE
#AmbientCapabilities=CAP_NET_BIND_SERVICE
###

[Install]
WantedBy=multi-user.target