wiki:jazz/09-01-14

Version 10 (modified by jazz, 16 years ago) (diff)

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2009-01-14

  • Trac Wiki 改名的終極方法: 到 db/trac.db 去改內容
    # sqlite3 db/trac.db
    sqlite> update wiki set name='BOINC/Server' where name='BOINC_Server';
    
  • 如果有附件(Attachment)的話,比較麻煩 (1) 改 wiki (2) 改 attachment (3) 必須到 attachments/wiki/ 目錄去搬檔案
    # sqlite3 db/trac.db
    sqlite> update wiki set name='FlyCircuit/2008-03-26' where name='FlyCircit/2008-03-26';
    sqlite> update attachment set id='FlyCircuit/2008-03-26' where id='FlyCircit/2008-03-26';
    sqlite> update wiki set name='FlyCircuit/2008-06-24' where name='FlyCircit/2008-06-24';
    sqlite> update attachment set id='FlyCircuit/2008-06-24' where id='FlyCircit/2008-06-24';
    

BUGFIX: jfbterm (4)

  • 在看 fbcommon.c 時,發現在這組出現錯誤的 mmap 前曾跑過另一組 mmap, 因此把參數印出來對照看看。
  • gdb debug 程序
    file jfbterm
    set args -e ls
    show args
    break fbcommon.c:500
    break fbcommon.c:557
    break fbcommon.c:566
    run
    p fb_fix
    c
    p fb_fix
    c
    p fb_fix.smem_len
    p p->soff
    p p->slen
    p fb_fix.mmio_len
    p p->moff
    p p->mlen
    
    root@intrepid:~/jfbterm-0.4.7-dev# gdb
    GNU gdb 6.8-debian
    Copyright (C) 2008 Free Software Foundation, Inc.
    License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
    This is free software: you are free to change and redistribute it.
    There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
    and "show warranty" for details.
    This GDB was configured as "x86_64-linux-gnu".
    (gdb) file jfbterm
    Reading symbols from /root/jfbterm-0.4.7-dev/jfbterm...done.
    (gdb) set args -e ls
    (gdb) show args
    Argument list to give program being debugged when it is started is "-e ls".
    (gdb) break fbcommon.c:500
    Breakpoint 1 at 0x40303d: file fbcommon.c, line 500.
    (gdb) break fbcommon.c:557
    Breakpoint 2 at 0x40327e: file fbcommon.c, line 557.
    (gdb) break fbcommon.c:566
    Breakpoint 3 at 0x403301: file fbcommon.c, line 566.
    (gdb) run
    Starting program: /root/jfbterm-0.4.7-dev/jfbterm -e ls
    ...略...
    Breakpoint 1, tfbm_open (p=0x6146e0) at fbcommon.c:501
    501             if (fb_var.yres_virtual != fb_var.yres) {
    (gdb) p fb_fix
    $1 = {id = "▒\204▒▒Q\177\000\000\006\000\000\000\000\000\000", smem_start = 21037808, 
      smem_len = 4269392626, type = 32593, type_aux = 0, visual = 0,
      xpanstep = 65535, ypanstep = 65535, ywrapstep = 65535, line_length = 1, mmio_start = 15, 
      mmio_len = 21076240, accel = 0, reserved = {53071, 64, 0}}
    (gdb) c
    Continuing.
    ...略...
    Breakpoint 2, tfbm_open (p=0x6146e0) at fbcommon.c:557
    557             p->smem = (u_char*)mmap(NULL, p->slen, PROT_READ|PROT_WRITE,
    (gdb) p fb_fix
    $2 = {id = "VESA VGA\000\000\000\000\000\000\000", smem_start = 4026531840, 
      smem_len = 1572864, type = 0, type_aux = 0, visual = 3, xpanstep = 0,
      ypanstep = 0, ywrapstep = 0, line_length = 1024, mmio_start = 0, 
      mmio_len = 0, accel = 0, reserved = {0, 0, 0}}
    (gdb) c
    Continuing.
    
    Breakpoint 3, tfbm_open (p=0x6146e0) at fbcommon.c:566
    566             if(p->mlen == 0)
    (gdb) p fb_fix.smem_len
    $3 = 1572864
    (gdb) p p->soff
    $4 = 0
    (gdb) p p->slen
    $5 = 1572864
    (gdb) p fb_fix.mmio_len
    $6 = 0
    (gdb) p p->moff
    $7 = 0
    (gdb) p p->mlen
    $8 = 0
    
fb_fix.smem_len = 1572864 p->soff = 0 p->slen = 1572864 mmap 成功
fb_fix.mmio_len = 0 p->moff = 0 p->mlen = 0 mmap 失敗 (因為 length = 0)
  • 從數據看起來,無論是從 SSH 登入,或在本機 tty 使用,所得到的 fb_fix.mmio_len = 0 是主要原因。只是 mmio 所代表的意涵,fbcommon.h 程式碼並無註解。
    <fbcommon.c>
    
    509         tfbm_get_fix_screen_info(p->fh, &fb_fix);
    
    244 static void tfbm_get_fix_screen_info(int fh, struct fb_fix_screeninfo *fix)
    245 {
    246         if (ioctl(fh, FBIOGET_FSCREENINFO, fix)) {
    247                 print_strerror_and_exit("ioctl FBIOGET_FSCREENINFO");
    248         }
    249 }