Android中init.rc文件的解析
本文分析Android中如何解析init.rc文件，重点描述了on action内的解析，并从解析的过程中总结出init.rc的语法规范。对init.rc的解析是在parse_config(): [system/core/init/init_parser.c]中进行的。解析发生在init全过程中的哪个阶段，参看《Android init进程启动过程分析》。一、解析过程1. 扫描init.rc中的token找到其中的 文件结束EOF/文本TEXT/新行NEWLINE，其中的空格‘ ’、‘\t’、‘\r’会被忽略，#开头的行也被忽略掉；而对于TEXT，空格‘ ’、‘\t’、‘\r’、‘\n’都是TEXT的结束标志。2. 对每一个TEXT token，都加入到args[]数组中3. 当遇到新一行（‘\n’）的时候，用args[0]通过lookup_keyword()检索匹配关键字；1) 对Section（on和service），调用parse_new_section() 解析：- 对on section，调用parse_action()，并设置解析函数parse_line为parse_line_action()- 对service section，调用parse_service()，并设置解析函数parse_line为parse_line_service()2) 对其他关键字的行（非on或service开头的地方，也就是没有切换section）调用parse_line()也就是，- 对于on section内的命令行，调用parse_line_action()解析；- 对于service section内的命令行，调用parse_line_service()解析。二、关键数据类型原型及关键数据定义2.1 Token的定义[cpp]#defineT_EOF 0#defineT_TEXT 1#defineT_NEWLINE 2#defineT_EOF 0#defineT_TEXT 1#defineT_NEWLINE 22.2 关键字定义[cpp]KEYWORD(capability, OPTION, 0, 0)KEYWORD(chdir, COMMAND, 1, do_chdir)KEYWORD(chroot, COMMAND, 1, do_chroot)KEYWORD(class, OPTION, 0, 0)KEYWORD(class_start, COMMAND, 1,do_class_start)KEYWORD(class_stop, COMMAND, 1, do_class_stop)KEYWORD(console, OPTION, 0, 0)KEYWORD(critical, OPTION, 0, 0)KEYWORD(disabled, OPTION, 0, 0)KEYWORD(domainname, COMMAND, 1, do_domainname)KEYWORD(exec, COMMAND, 1, do_exec)KEYWORD(export, COMMAND, 2, do_export)KEYWORD(group, OPTION, 0, 0)KEYWORD(hostname, COMMAND, 1, do_hostname)KEYWORD(ifup, COMMAND, 1, do_ifup)KEYWORD(insmod, COMMAND, 1, do_insmod)KEYWORD(import, COMMAND, 1, do_import)KEYWORD(keycodes, OPTION, 0, 0)KEYWORD(mkdir, COMMAND, 1, do_mkdir)KEYWORD(mount, COMMAND, 3, do_mount)KEYWORD(on, SECTION, 0, 0)KEYWORD(oneshot, OPTION, 0, 0)KEYWORD(onrestart, OPTION, 0, 0)KEYWORD(restart, COMMAND, 1, do_restart)KEYWORD(service, SECTION, 0, 0)KEYWORD(setenv, OPTION, 2, 0)KEYWORD(setkey, COMMAND, 0, do_setkey)KEYWORD(setprop, COMMAND, 2, do_setprop)KEYWORD(setrlimit, COMMAND, 3, do_setrlimit)KEYWORD(socket, OPTION, 0, 0)KEYWORD(start, COMMAND, 1, do_start)KEYWORD(stop, COMMAND, 1, do_stop)KEYWORD(trigger, COMMAND, 1, do_trigger)KEYWORD(symlink, COMMAND, 1, do_symlink)KEYWORD(sysclktz, COMMAND, 1, do_sysclktz)KEYWORD(user, OPTION, 0, 0)KEYWORD(wait, COMMAND, 1, do_wait)KEYWORD(write, COMMAND, 2, do_write)KEYWORD(copy, COMMAND, 2, do_copy)KEYWORD(chown, COMMAND, 2, do_chown)KEYWORD(chmod, COMMAND, 2, do_chmod)KEYWORD(loglevel, COMMAND, 1, do_loglevel)KEYWORD(ioprio, OPTION, 0, 0)KEYWORD(capability, OPTION, 0, 0)KEYWORD(chdir, COMMAND, 1, do_chdir)KEYWORD(chroot, COMMAND, 1, do_chroot)KEYWORD(class, OPTION, 0, 0)KEYWORD(class_start, COMMAND, 1,do_class_start)KEYWORD(class_stop, COMMAND, 1, do_class_stop)KEYWORD(console, OPTION, 0, 0)KEYWORD(critical, OPTION, 0, 0)KEYWORD(disabled, OPTION, 0, 0)KEYWORD(domainname, COMMAND, 1, do_domainname)KEYWORD(exec, COMMAND, 1, do_exec)KEYWORD(export, COMMAND, 2, do_export)KEYWORD(group, OPTION, 0, 0)KEYWORD(hostname, COMMAND, 1, do_hostname)KEYWORD(ifup, COMMAND, 1, do_ifup)KEYWORD(insmod, COMMAND, 1, do_insmod)KEYWORD(import, COMMAND, 1, do_import)KEYWORD(keycodes, OPTION, 0, 0)KEYWORD(mkdir, COMMAND, 1, do_mkdir)KEYWORD(mount, COMMAND, 3, do_mount)KEYWORD(on, SECTION, 0, 0)KEYWORD(oneshot, OPTION, 0, 0)KEYWORD(onrestart, OPTION, 0, 0)KEYWORD(restart, COMMAND, 1, do_restart)KEYWORD(service, SECTION, 0, 0)KEYWORD(setenv, OPTION, 2, 0)KEYWORD(setkey, COMMAND, 0, do_setkey)KEYWORD(setprop, COMMAND, 2, do_setprop)KEYWORD(setrlimit, COMMAND, 3, do_setrlimit)KEYWORD(socket, OPTION, 0, 0)KEYWORD(start, COMMAND, 1, do_start)KEYWORD(stop,补充：移动开发 , Android ,
