内核FAQ(2001.05.06～2001.05.16)

内核FAQ(2001.05.06～2001.05.16)

http://LinuxAid.com.cn axing

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1、 请问linux的启动过程

2、 未改版本重编译内核后要安装吗？

3、 编译8390.c的一个问题

4、 LKM内核编程问题

5、 sk_buff

6、 在蓝点Linux 2.2.13 上编译可加载内核模块出错

1、请问linux的启动过程

bios读入bootsect.s，bootsect.s读入setup.s和kernel，然后将控制权交给setup.s，然后呢？kernel在引导过程中起什么作用？我知道Loading...是表示bootsect在读入内核，那么其他的信息是进行什么操作的时候出现的呢？还有，rc.sysinit和rc.local在启动中起什么作用？我对linux引导过程还是很糊涂，请那个大哥给我指点迷津，多谢多谢。

setup.S是为启动保护模式前做准备的，目的是建立内核的运行环境，当控制转到head.S中后，工作主要是建立一个4M的页表以及一个什么也干不了的IDT表，并且建立init的堆栈。最后跳转到start_kernel这个c函数中执行。在这里面工作就在前面已经建立的4M内存映射的基础上继续进行更高等的初始化了。

基本流程是：bios->bootsect.S->setup.S->head.S->start_kernel->init-> do_basic_setup->创建init进程。

其他信息大部分在do_basic_setup中打印出来的，主要是各种设备的信息。rc.sysinit和rc.local是在init进程里面被解释执行。主要是创建一些精灵进程和初始化一些网络服务进程。具体的看看相关的脚本文件吧。

2、未改版本重编译内核后要安装吗？

我要在RH6.2装Oracle8i，按照说明需要修改系统内核中的共享内存和段的数值后重新编译，未升级内核。

具体修改shmparam.h中的SHMMAX、SHMMNI、SHMSEG的数值及sem.h中的SEMMSL、SEGMNS、SEMOPM的数值。

重编译过程中用make mrproper正常；运行make config出现许多提示，统统按回车键使用默认值；make dep、make clean、make bzImage都较正常。然后将bzImage复制到/boot目录下，修改/etc/lilo.conf文件内的内容，使image=/boot/bzImage-2.2.14，然后运行lilo，再重新启动。

启动后提示两个错误，其中一个是以太网错，进入linux后网络不能用。

请各位内核高手问：1.以上步骤哪些有错？2.我未升级内核，仅修改部分参数，是否可以不做上述的全过程？3.如何知道系统已经确实按新的SHMMAX等值运行了。

编译内核前，配置时干吗用make config哪，可以用make menuconfig或者make xconfig,要选择网卡驱动。

3、编译8390.c的一个问题

请问如何用gcc编译8390.c 和ne.c 的LINUX内核驱动程序。

试试gcc -O3 -Wall -DMODULE -D__KERNEL__ -DLINUX -c 8309.c(ne.c)

redhat7.O市场反映很不好，存在很多问题，不适合作编程开发，建议用6.2版，或7.1版。

4、LKM内核编程问题

编译的LKM程序在红旗linux下可以编译通过,但在Turbo linux 编译时提示头文件出错. 不知道是何原因,如何处理.

你用的是哪个版本的内核，2。2后的内核应该用copy_from_user代替memcpy_fromfs

5、sk_buff

哪位大侠知道udp包的校验和是在哪个函授里计算并写到sk_buff中的，请指点小弟不胜感激，谢谢。

/usr/src/linux/net/ipv4/udp.c中：

udp_check(....)调用csum_tcpudp_magic计算校验和，你可查看/usr/src/linux/include/asm-i386/checksum.h查看具体的算法 csum是check sum 的一四。

写入sk_buff是在udp_rcv(....)完成的。

6、在蓝点Linux 2.2.13 上编译可加载内核模块出错

原程序如下：

/*hello.c*/

#define MODULE

#define __KERNEL__

#include <linux/module.h>

#include <linux/kernel.h>

#include <asm/unistd.h>

#include <sys/syscall.h>

#include <sys/types.h>

#include <asm/fcntl.h>

#include <asm/errno.h>

#include <linux/types.h>

#include <linux/dirent.h>

#include <sys/mman.h>

#include <linux/string.h>

#include <linux/fs.h>

#include <linux/malloc.h>

extern void* sys_call_table[];

int (*orig_open)(const char *pathname, int flag, mode_t mode);

int my_open(const char *pathname, int flag, mode_t mode)

{

char *kernel_pathname;

char hide[]="ourtool";

/*转换到内核空间*/

kernel_pathname = (char*) kmalloc(256, GFP_KERNEL);

memcpy_fromfs(kernel_pathname, pathname, 255);

if(strstr(kernel_pathname, (char*)&hide ) != NULL)

{

kfree(kernel_pathname);

/*返回错误代码,'file dos not exist'*/

return -ENOENT;

}

else

{

kfree(kernel_pathname);

/*一切OK,这不是我们的工具*/

return orig_open(pathname, flag, mode);

}

}

int init_module(void) /*初始化模块*/

{

orig_open=sys_call_table[SYS_open];

sys_call_table[SYS_open]=my_open;

return 0;

}

void cleanup_module(void) /*卸载模块*/

{

sys_call_table[SYS_open]=orig_open;

}

/*end of hello.c*/

我以超级用户以如下命令进行编译：

gcc -c -O3 hello.c

编译不成功，提示如下信息：

In file included from /usr/include/linux/affs_fs_i.h:5,

from /usr/include/linux/fs.h:270,

from hello.c:14:

/usr/include/linux/time.h:69: warning: `FD_SET' redefined

/usr/include/sys/select.h:63: warning: this is the location of the previous definition

/usr/include/linux/time.h:70: warning: `FD_CLR' redefined

/usr/include/sys/select.h:64: warning: this is the location of the previous definition

/usr/include/linux/time.h:71: warning: `FD_ISSET' redefined

/usr/include/sys/select.h:65: warning: this is the location of the previous definition

/usr/include/linux/time.h:72: warning: `FD_ZERO' redefined

/usr/include/sys/select.h:66: warning: this is the location of the previous definition

In file included from /usr/include/linux/affs_fs_i.h:5,

from /usr/include/linux/fs.h:270,

from hello.c:14:

/usr/include/linux/time.h:9: redefinition of `struct timespec'

/usr/include/linux/time.h:51: parse error before `suseconds_t'

/usr/include/linux/time.h:51: warning: no semicolon at end of struct or union

/usr/include/linux/time.h:88: field `it_interval' has incomplete type

/usr/include/linux/time.h:89: field `it_value' has incomplete type

In file included from /usr/include/linux/fs.h:270,

from hello.c:14:

/usr/include/linux/affs_fs_i.h:11: field `kc_lru_time' has incomplete type

In file included from /usr/include/linux/fs.h:272,

from hello.c:14:

/usr/include/linux/efs_fs_i.h:13: parse error before `efs_ino_t'

/usr/include/linux/efs_fs_i.h:13: warning: data definition has no type or storage class

/usr/include/linux/efs_fs_i.h:49: parse error before `uint32_t'

/usr/include/linux/efs_fs_i.h:49: warning: no semicolon at end of struct or union

/usr/include/linux/efs_fs_i.h:57: parse error before `}'

In file included from /usr/include/linux/coda_fs_i.h:14,

from /usr/include/linux/fs.h:273,

from hello.c:14:

/usr/include/linux/coda.h:109: warning: redefinition of `u_quad_t'

/usr/include/sys/types.h:38: warning: `u_quad_t' previously declared here

In file included from /usr/include/linux/sched.h:13,

from /usr/include/linux/mm.h:4,

from /usr/include/linux/slab.h:14,

from /usr/include/linux/malloc.h:4,

from hello.c:15:

/usr/include/linux/times.h:5: parse error before `clock_t'

/usr/include/linux/times.h:5: warning: no semicolon at end of struct or union

/usr/include/linux/times.h:6: warning: data definition has no type or storage class

/usr/include/linux/times.h:7: parse error before `tms_cutime'

/usr/include/linux/times.h:7: warning: data definition has no type or storage class

/usr/include/linux/times.h:8: parse error before `tms_cstime'

/usr/include/linux/times.h:8: warning: data definition has no type or storage class

In file included from /usr/include/linux/sched.h:14,

from /usr/include/linux/mm.h:4,

from /usr/include/linux/slab.h:14,

from /usr/include/linux/malloc.h:4,

from hello.c:15:

/usr/include/linux/timex.h:159: field `time' has incomplete type

In file included from /usr/include/linux/signal.h:5,

from /usr/include/linux/sched.h:23,

from /usr/include/linux/mm.h:4,

from /usr/include/linux/slab.h:14,

from /usr/include/linux/malloc.h:4,

from hello.c:15:

/usr/include/asm/siginfo.h:48: parse error before `clock_t'

/usr/include/asm/siginfo.h:48: warning: no semicolon at end of struct or union

/usr/include/asm/siginfo.h:48: warning: no semicolon at end of struct or union

/usr/include/asm/siginfo.h:49: warning: no semicolon at end of struct or union

/usr/include/asm/siginfo.h:50: warning: data definition has no type or storage class

/usr/include/asm/siginfo.h:62: parse error before `}'

/usr/include/asm/siginfo.h:62: warning: data definition has no type or storage class

/usr/include/asm/siginfo.h:63: parse error before `}'

/usr/include/asm/siginfo.h:63: warning: data definition has no type or storage class

In file included from /usr/include/linux/sched.h:23,

from /usr/include/linux/mm.h:4,

from /usr/include/linux/slab.h:14,

from /usr/include/linux/malloc.h:4,

from hello.c:15:

/usr/include/linux/signal.h:15: parse error before `siginfo_t'

/usr/include/linux/signal.h:15: warning: no semicolon at end of struct or union

In file included from /usr/include/linux/sched.h:71,

from /usr/include/linux/mm.h:4,

from /usr/include/linux/slab.h:14,

from /usr/include/linux/malloc.h:4,

from hello.c:15:

/usr/include/linux/resource.h:22: field `ru_utime' has incomplete type

/usr/include/linux/resource.h:23: field `ru_stime' has incomplete type

In file included from /usr/include/linux/mm.h:4,

from /usr/include/linux/slab.h:14,

from /usr/include/linux/malloc.h:4,

from hello.c:15:

/usr/include/linux/sched.h:288: field `times' has incomplete type

In file included from /usr/include/linux/mm.h:4,

from /usr/include/linux/slab.h:14,

from /usr/include/linux/malloc.h:4,

from hello.c:15:

/usr/include/linux/sched.h:506: parse error before `siginfo_t'

hello.c:44: parse error before character 0241

hello.c:47: conflicting types for `sys_call_table'

hello.c:16: previous declaration of `sys_call_table'

hello.c:47: invalid initializer

hello.c:47: warning: data definition has no type or storage class

hello.c:48: parse error before `return'

hello.c:51: parse error before character 0241

不知究竟错在何处，希望各位师兄多多指教。'

/*hello.c*/

#define MODULE

#define __KERNEL__

#include <linux/module.h>

#include <linux/kernel.h>

#include <asm/unistd.h>

#include <sys/syscall.h>

//#include <sys/types.h>

//#include <asm/fcntl.h>

#include <asm/errno.h>

//#include <linux/types.h>

//#include <linux/dirent.h>

//#include <sys/mman.h>

#include <linux/string.h>

//#include <linux/fs.h>

#include <linux/malloc.h>

extern void* sys_call_table[];

int (*orig_open)(const char *pathname, int flag,..

.....

试一试

您在编译时再加上 -V2.7.2.3 选项试试，我多次遇问题，这样做好象百试百中

责任编辑：axing(2001-06-06 17:48)