Changes between Version 1 and Version 2 of jazz/09-01-22


Ignore:
Timestamp:
Jan 22, 2009, 2:12:41 AM (15 years ago)
Author:
jazz
Comment:

--

Legend:

Unmodified
Added
Removed
Modified

  • jazz/09-01-22

    v1 v2  
    11= 2009-01-22 =
    22
     3== DRBL Shutdown Agent ==
     4
     5 * [源起] 由於 DRBL Client 在 NFS 斷線後會因為 ROOTFS 消失而找不到關機程序所需的檔案。因此需要有一個背景程序持續等在記憶體中來協助 DRBL Client 關閉電源。
     6 * 準備 sysvinit 套件環境
     7{{{
     8# apt-get install dpkg-dev build-essential
     9# apt-get source sysvinit
     10# apt-get build-dep sysvinit
     11# cd sysvinit-2.86.ds1/src
     12~/sysvinit-2.86.ds1/src# vi Makefile
     13}}}
     14{{{
     15#!diff
     16--- Makefile.org        2009-01-22 10:00:03.000000000 +0800
     17+++ Makefile    2009-01-22 09:15:42.000000000 +0800
     18@@ -9,8 +9,8 @@
     19-CFLAGS = -Wall -O2 -fomit-frame-pointer -D_GNU_SOURCE
     20-LDFLAGS= -s
     21+CFLAGS = -g -Wall -O2 -fomit-frame-pointer -D_GNU_SOURCE # 加入 -g ，讓 gcc 加入 DEBUG Symbol
     22+LDFLAGS=                                                 # 拿掉 -s ，讓 LD 進行 Linking 時不進行 strip
     23}}}
     24{{{
     25#!sh
     26~/sysvinit-2.86.ds1/src# make
     27~/sysvinit-2.86.ds1/src# nm init                          # 用 nm 可以看到是否有保留 Symbol
     28~/sysvinit-2.86.ds1/src# file init                        # 顯示 not stripped 才會保留 Symbol 哦!
     29init: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), for GNU/Linux 2.4.1, dynamically linked (uses shared libs), for GNU/Linux 2.4.1, not stripped
     30}}}
     31 * 先前有追蹤過 shutdown.c 跟 halt.c 的原始碼，發現最後都還是呼叫 init 來執行關機程序。因此這次改追蹤 init.c
     32 * 用 gdb 追蹤 init 0 的程序
     33{{{
     34~/sysvinit-2.86.ds1/src# gdb init
     35(gdb) set args 0
     36(gdb) show args
     37Argument list to give program being debugged when it is started is "0".
     38(gdb) br 2598
     39Breakpoint 1 at 0x804e140: file init.c, line 2598.
     40(gdb) br 2555
     41Breakpoint 2 at 0x8049bfd: file init.c, line 2555.
     42(gdb) run
     43Starting program: /root/sysvinit-2.86.ds1/src/init 0
     44Failed to read a valid object file image from memory.
     45
     46Breakpoint 1, main (argc=1282785413, argv=0x54a165) at init.c:2598
     472598    {
     48(gdb) c
     49Continuing.
     50
     51Breakpoint 2, telinit (progname=0xbfff5c53 "init", argc=2, argv=0xbfff5b34)
     52    at init.c:2555
     532555            SETSIG(sa, SIGALRM, signal_handler, 0);
     54(gdb) handle SIGALRM nopass
     55Signal        Stop      Print   Pass to program Description
     56SIGALRM       No        No      No              Alarm clock
     57(gdb) s
     58}}}
    359 * 用 strace init 0 觀察關機程序
    460{{{
    561root@debian:~/sysvinit-2.86.ds1/src# strace init 0
    662execve("/sbin/init", ["init", "0"], [/* 14 vars */]) = 0
    7 uname({sys="Linux", node="debian", ...}) = 0
    8 brk(0)                                  = 0x8051000
    9 access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
    10 mmap2(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb7f8c000
    11 access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
    12 open("/etc/ld.so.cache", O_RDONLY)      = 3
    13 fstat64(3, {st_mode=S_IFREG|0644, st_size=18455, ...}) = 0
    14 mmap2(NULL, 18455, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb7f87000
    15 close(3)                                = 0
    16 access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
    17 open("/lib/libsepol.so.1", O_RDONLY)    = 3
    18 read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\0200\0"..., 512) = 512
    19 fstat64(3, {st_mode=S_IFREG|0644, st_size=219824, ...}) = 0
    20 mmap2(NULL, 265152, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb7f46000
    21 mmap2(0xb7f7c000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x35) = 0xb7f7c000
    22 mmap2(0xb7f7d000, 39872, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb7f7d000
    23 close(3)                                = 0
    24 access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
    25 open("/lib/libselinux.so.1", O_RDONLY)  = 3
    26 read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0P8\0\000"..., 512) = 512
    27 fstat64(3, {st_mode=S_IFREG|0644, st_size=79368, ...}) = 0
    28 mmap2(NULL, 84884, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb7f31000
    29 mmap2(0xb7f44000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x12) = 0xb7f44000
    30 close(3)                                = 0
    31 access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
    32 open("/lib/tls/i686/cmov/libc.so.6", O_RDONLY) = 3
    33 read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\240O\1"..., 512) = 512
    34 fstat64(3, {st_mode=S_IFREG|0644, st_size=1241392, ...}) = 0
    35 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb7f30000
    36 mmap2(NULL, 1247388, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb7dff000
    37 mmap2(0xb7f26000, 28672, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x127) = 0xb7f26000
    38 mmap2(0xb7f2d000, 10396, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb7f2d000
    39 close(3)                                = 0
    40 access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
    41 open("/lib/tls/i686/cmov/libdl.so.2", O_RDONLY) = 3
    42 read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\20\f\0"..., 512) = 512
    43 fstat64(3, {st_mode=S_IFREG|0644, st_size=9592, ...}) = 0
    44 mmap2(NULL, 12404, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb7dfb000
    45 mmap2(0xb7dfd000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1) = 0xb7dfd000
    46 close(3)                                = 0
    47 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb7dfa000
    48 mprotect(0xb7f26000, 20480, PROT_READ)  = 0
    49 set_thread_area({entry_number:-1 -> 6, base_addr:0xb7dfa6c0, limit:1048575, seg_32bit:1, contents:0, read_exec_only:0, limit_in_pages:1, seg_not_present:0, usea                                                                             ble:1}) = 0
    50 munmap(0xb7f87000, 18455)               = 0
    51 access("/etc/selinux/", F_OK)           = -1 ENOENT (No such file or directory)
    52 brk(0)                                  = 0x8051000
    53 brk(0x8072000)                          = 0x8072000
    54 open("/proc/mounts", O_RDONLY|O_LARGEFILE) = 3
    55 fstat64(3, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0
    56 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb7f8b000
    57 read(3, "rootfs / rootfs rw 0 0\nnone /sys"..., 1024) = 305
    58 read(3, "", 1024)                       = 0
    59 close(3)                                = 0
    60 munmap(0xb7f8b000, 4096)                = 0
    61 umask(022)                              = 022
    62 geteuid32()                             = 0
    63 getpid()                                = 2159
    6463rt_sigaction(SIGALRM, {0x8049ad0, [], 0}, NULL, 8) = 0
    6564alarm(3)                                = 0
    … …  
    6968alarm(0)                                = 3
    7069exit_group(0)                           = ?
    71 Process 2159 detached
    72 root@debian:~/sysvinit-2.86.ds1/src#
    7370}}}