嵌入式

#嵌入式Linux最小系统移植# busybox分析和移植记录

2019-07-12 20:48发布

站内文章 / 嵌入式Linux
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//busybox/init.c 1.init_main过程分析 init_main parse_inittab(); file = fopen(INITTAB, "r"); //#define INITTAB "/etc/inittab" /* inittab file location */ new_init_action(a->action, command, id); //1.创建一个init-action结构，填充 //2.加入init_action_list链表 run_actions(SYSINIT); waitfor(a, 0); run(a); waitpid(runpid, &status, 0); delete_init_action(a); run_actions(WAIT); waitfor(a, 0); run(a); waitpid(runpid, &status, 0); delete_init_action(a); run_actions(ONCE); run(a); delete_init_action(a); while (1) { run_actions(RESPAWN); if (a->pid == 0) { a->pid = run(a);/ run_actions(ASKFIRST); if (a->pid == 0) { a->pid = run(a); " Please press Enter to activate this console. "; wpid = wait(NULL); while (wpid > 0) { a->pid = 0; } } } 2.new_init_action举例分析 new_init_action(ASKFIRST, bb_default_login_shell, VC_2); new_init_action(ASKFIRST, "-/bin/sh", "/dev/tty2"); //查找init_action_list中是否已经存在要添加的init_action结构 //存在，则覆盖 for (a = last = init_action_list; a; a = a->next) { /* don't enter action if it's already in the list, * but do overwrite existing actions */ if ((strcmp(a->command, command) == 0) && (strcmp(a->terminal, cons) == 0) ) { a->action = action; return; } last = a; } //不存在，则创建 new_action = xzalloc(sizeof(struct init_action)); if (last) { last->next = new_action; } else { init_action_list = new_action; } #define LIBBB_DEFAULT_LOGIN_SHELL "-/bin/sh" const char bb_default_login_shell[] ALIGN1 = LIBBB_DEFAULT_LOGIN_SHELL; # define VC_2 "/dev/tty2" #define ASKFIRST 0x004 3.inittab格式 # Format for each entry: ::: # :The contents of this field are appended to "/dev/" and used as-is. # : Valid actions include: sysinit, respawn, askfirst, wait, once, # restart, ctrlaltdel, and shutdown. # : Specifies the process to be executed and its command line. 4.编译、安装busybox #make menuconfig 出错：提示Makefile:1449: *** mixed implicit and normal rules. Stop. 解决：/*翻译为中文：混合的和隐含普通规则 是由于我的系统的make工具太新（系统：fedora15），make的旧版规则已经无法兼容新版。 按照以下方式，问题得到解决： 修改前：416行 config %config: scripts_basic outputmakefile FORCE 修改后：416 行 %config: scripts_basic outputmakefile FORCE 修改前：1449 行 / %/: prepare scripts FORCE 修改后：1449 行 %/: prepare scripts FORCE*/ 出错：error: field 'in' has incomplete type 解决：arm-linux 交叉编译工具链 在 usr/local/arm/4.3.2/arm-none-linux-gnueabi/libc/usr/include/linux/netfilter.h 头文件的开头 添加缺少的头文件： #include 出错：undefined reference to `__cpu_to_be16 解决：修改 networking/libiproute/iptunnel.c文件 在#include 后面加上 #include #make CONFIG_PREFIX=/home/invoker/busybox/myfilesystem/ install #cd /home/invoker/busybox/myfilesystem/ #ls bin linuxrc sbin usr # mkdir dev # cd dev/ # ls /dev/console /dev/null -l crw-------. 1 root root 5, 1 12月 4 11:51 /dev/console crw-rw-rw-. 1 root root 1, 3 12月 4 11:50 /dev/null # mknod console c 5 1 # mknod null c 1 3 [root@localhost dev]# ls // dev/console /dev/null console null //安装gibc库 [root@localhost myfilesystem]# mkdir lib [root@localhost myfilesystem]# ls bin dev etc lib linuxrc sbin usr [root@localhost myfilesystem]# cd /home/invoker/tools/opt/FriendlyARM/toolschain/4.4.3/arm-none-linux-gnueabi/lib [root@localhost lib]# cp *.so* /home/invoker/busybox/myfilesystem/lib -d //到此可以生成最小文件系统 //制作yaffs2文件系统 出错：starting pid 755, tty '': '/etc/init.d/rcS' 一直卡在/etc/init.d/rcS 解决：使用Busybox默认配置，Open(etc/inittab) = NULL

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