system/nxinit: skip empty lines in init.rc parser

[Zepp-Hanzj]

Description

Empty lines in init.rc caused parsing to fail with -EINVAL because init_parse_arguments() returns 0 for empty strings, triggering the argc < 1 error path in init_action_parse() and accessing uninitialized argv[0] in init_service_parse().

Fix by skipping empty lines and lines containing only whitespace before attempting to match section keywords or calling parser callbacks.

Fixes #3513

Changes

• system/nxinit/parser.c: Add empty/whitespace-only line skip logic in init_parse_config_file()

Testing

Verified on sim:nsh with NXINIT enabled and an init.rc containing empty lines:

on boot
    start console
    sleep 1
                    ← empty line (previously caused -EINVAL)
service console sh
    class core
    restart_period 1000

Before fix:

Error Parse /etc/init.d/init.rc -22

After fix:

nsh> ps
  TID   PID  PPID PRI POLICY   TYPE    NPX STATE    EVENT     SIGMASK            STACK COMMAND
    4     4     0 100 FIFO     Task      - Waiting  Signal    0000000000000000 0067496 init_main
    5     5     4 100 FIFO     Task      - Running            0000000000000000 0067504 sh
    6     6     4 100 FIFO     Task      - Ready              0000000000000000 0067464 system -c sleep 1

NXInit successfully parsed the init.rc with empty lines and started the console service.

[acassis]

@jerpelea I think this fix also is important