ContextOS/usr/wiki/自然/编程/后端技术栈/linux.md

linux

• 官网：https://www.linux.org/

• 文档：https://www.kernel.org/doc/html/latest/

• 源码：https://mirrors.edge.kernel.org/pub/linux/kernel/v3.x/linux-3.7.4.tar.gz

• 开源：https://github.com/torvalds/linux

• 代理：https://mirror.tuna.tsinghua.edu.cn/kernel/v3.x/linux-3.7.4.tar.gz

内核源码

lib arch init kernel include drivers ipc net mm fs

firmware security crypto sound block virt

tools scripts samples Makefile Kconfig Kbuild usr

README COPYING CREDITS Documentation MAINTAINERS REPORTING-BUGS

系统启动

startup_32() // linux-2.6.12/arch/i386/kernel/head.S:57
start_kernel() // linux-2.6.12/init/main.c:424
	sched_init()
    trap_init() // arch/i386/kernel/traps.c
	init_IRQ()
	init_timers()
	softirq_init()
    time_init() // arch/i386/kernel/time.c
        time_init_hook()
            setup_irq(0, timer_interrupt)

进程调度

schedule()

系统中断

interrupt() // arch/i386/kernel/entry.S:397
do_IRQ() // arch/i386/kernel/irq.c:51
    __do_IRQ() // kernel/irq/handle.c:107
        handle_IRQ_event()

do_softirq() // arch/i386/kernel/softirq.c:158
    __do_softirq() // kernel/softirq.c:74

tasklet_schedule() // include/linux/interrupt.h
    __tasklet_schedule() // kernel/softirq.c:223

run_workqueue() // kernel/workqueue.c:145

并发同步

atomic_add() // include/asm-i386/atomic.h
spin_lock_irq() // include/linux/spinlock.h
down_interruptible() // include/asm-i386/semaphore.h
wait_for_completion() // kernel/sched.c

时间管理

timer_interrupt() // arch/i386/kernel/time.c:292
do_timer_interrupt() // arch/i386/kernel/time.c:250
    do_timer_interrupt_hook()
        do_timer() // kernel/timer.c:925

系统调用

system_call() // arch/i386/kernel/entry.S:225
sys_call_table[] // arch/i386/kernel/syscall_table.S
	.long sys_restart_syscall	/* 0 - old "setup()" system call, used for restarting */
	.long sys_exit() // kernel/exit.c:859
        do_exit()
        exit_mm()
        exit_sem()
        __exit_files()
        __exit_fs()
        exit_namespace()
        exit_thread()
        cpuset_exit()
        exit_keys()
        exit_notify()
        schedule()
	.long sys_fork // arch/i386/kernel/process.c:645
        do_fork() // kernel/fork.c:1192
            copy_process()
                dup_task_struct()
                copy_files()
                copy_fs()
                copy_sighand()
                copy_signal()
                copy_mm()
                sched_fork()
            wake_up_new_task()
	.long sys_read
	.long sys_write
	.long sys_open		/* 5 */
        get_unused_fd()
        filp_open()
            open_namei()
                path_lookup()
            dentry_open()
        fd_install()

	.long sys_close
	.long sys_waitpid
	.long sys_creat
	.long sys_link
	.long sys_unlink	/* 10 */
	.long sys_execve
	.long sys_chdir
	.long sys_time
...

进程管理

struct task_struct {
    // 进程状态
    state long / TASK_RUNNING // include/linux/sched.h:108

    // 线程信息
    thread_info *struct thread_info
        task *struct task_struct
        status

    // 进程树
    parent *struct task_struct
    children struct list_head
    sibling struct list_head

    mm *struct mm_struct
    binfmt *struct linux_binfmt
    thread struct thread_struct
        esp0
        eip
        esp
        fs
        gs

    fs *struct fs_struct
    files *struct files_struct
    signal *struct signal_struct

    pid pid_t
    tgit pid_t
}

Compile

linux-3.7.4/Makefile
include $(srctree)/arch/$(SRCARCH)/Makefile # linux-3.7.4/Makefile:495

sudo apt-get install libncurses5-dev make defconfig make menuconfig make make tags

GCC

gcc -E hi.c -o hi.i gcc -S hi.c gcc -c hi.c

ar -r hi.a hi.o he.o gcc -shared -fPIC -o hi.so hi.c he.c gcc -L./ -lhi main.c

nm readelf -S hi.o objdump -d hi.o hexdump -C hi.o

GRUB

• 下载：ftp://ftp.gnu.org/gnu/grub/grub-2.00.tar.gz BIOS MBR GRUB

内核启动

startup_32() // arch/x86/kernel/head_32.S:88
i386_start_kernel() // arch/x86/kernel/head32.c:31
start_kernel() // init/main.c:468
    mm_init()
    sched_init()
    console_init()
    signals_init()
    rest_init()
        kernel_thread(kernel_init)
            do_fork() // kernel/fork.c:1548
                copy_process()
                wake_up_new_task() // kernel/sched/core.c:1622
                    activate_task()
                        enqueue_task(rq, p)

kernel_init() // init/main.c:805
    run_init_process()
        kernel_execve() // fs/exec.c:1710
            do_execve()
                do_execve_common()
                    open_exec()
                    sched_exec() // kernel/sched/core.c:2538
                        select_task_rq()
                    bprm_mm_init()
                    prepare_binprm()
                    search_binary_handler()
                        formats[i]->load_binary()

fair_sched_class() // kernel/sched/fair.c:5308
    select_task_rq_fair()
    pick_next_task_fair()
        pick_next_entity()
            __pick_first_entity()
                rb_entry()

formats[i]->load_binary()
    load_elf_binary() // fs/binfmt_elf.c:561
        current->mm->start_stack
        set_brk(elf_bss, elf_brk)

        start_thread() // arch/x86/kernel/process_32.c:200
formats[i]->load_binary()
    load_script()
        bprm_change_interp()
        open_exec()
        prepare_binprm()
        search_binary_handler()

struct task_struct { // linux-3.7.4/include/linux/sched.h:1190
    mm *struct mm_struct
        start_code
        end_code
        start_data
        end_data
        start_brk
        brk
        mmap_base
        start_stack
        arg_start
        arg_end
        env_start
        env_end

    thread struct thread_struct
        sp0
        sp
        es
        ds
        fsindex
        gsindex
        ip
        fs
        gs

    fs *struct fs_struct
    files *struct files_struct
    pid pid_t
    tgid pit_t
}