在内核中读写配置文件

在内核中读写配置文件，读文件我测试过，写文件还没。这段代码摘自网络，源出处已无可考。

#define FILE_MAX_SIZE	2048			/*maximum size of configure file*/
char filebuff[FILE_MAX_SIZE];
int filesize= 0;
struct file *filcp = NULL;
#define LEFT_BRACE '['
#define RIGHT_BRACE ']'
#define FILEC ("./sys.conf")
	

int newline(char c)
{
	return ('\n' == c ||  '\r' == c )? 1 : 0;
}

int end_of_string(char c)
{
	return '\0'==c? 1 : 0;
}

int left_barce(char c)
{
	return LEFT_BRACE == c? 1 : 0;
}

int isspace(char c)
{
	return ' ' == c ?1:0;
}

int isright_brace(char c )
{
	return RIGHT_BRACE == c ? 1 : 0;
}


int load_ini_file(void)
{
	int i=0;
	ssize_t ret;
	mm_segment_t old_fs;

	ipline = 0;
	filesize= 0;

	memset(filebuff,0,sizeof(filebuff));
	
	/*open readonly configure file */
	filcp = filp_open(FILEC, O_RDONLY , 0644);
	if(IS_ERR(filcp))
		printk(KERN_EMERG"open error...\n");

	/*store user data space */
	old_fs = get_fs();

	/*set kernel space in order to operate file in kernel*/
	set_fs(get_ds());

	filcp->f_op->llseek(filcp,0,0);

	do
	{
		ret = filcp->f_op->read(filcp, &filebuff[i], 1, &filcp->f_pos);
		if(ret > 0)
		{
			//printk(KERN_EMERG"%c",buff[i]);
		}
		else if(ret == 0)
		{
			//printk(KERN_EMERG"read nothing.............\n");
		}
		else 
		{
			printk(KERN_EMERG"read error\n");
			set_fs(old_fs);
			filp_close(filcp,NULL);
	
			return -1;
		}

		if(i >= FILE_MAX_SIZE -1)
		{
			printk(KERN_EMERG"read overcoving FILE_MAX_SIZE error\n");
			set_fs(old_fs);
			filp_close(filcp,NULL);
			return -1;
		}
	}while(filebuff[i++] > 0);

	set_fs(old_fs);

	filebuff[i]='\0';
	filesize = i;

	filp_close(filcp,NULL);
	return 1;
}
//

int parse_file(const char *section, const char *key, const char *buf,int *sec_s,int *sec_e,
					  int *key_s,int *key_e, int *value_s, int *value_e)
{
	const char *p = buf;
	int i=0;

	if(buf == NULL || section == NULL || key == NULL)
		return -1;

	*sec_e = *sec_s = *key_e = *key_s = *value_s = *value_e = -1;

	while( !end_of_string(p[i]) ) {
		/*find the section*/
		if( ( 0==i ||  newline(p[i-1]) ) && left_barce(p[i]) )
		{
			int section_start=i+1;

			/*find the ']'*/
			do {
				i++;
			} while( !isright_brace(p[i]) && !end_of_string(p[i]));

			if( 0 == strncmp(p+section_start,section, i-section_start)) {
				int newline_start=0;

				i++;

				/*Skip over space char after ']'*/
				while(isspace(p[i])) {
					i++;
				}

				/*find the section*/
				*sec_s = section_start;
				*sec_e = i;

				while( ! (newline(p[i-1]) && left_barce(p[i])) 
				&& !end_of_string(p[i]) ) {
					int j=0;
					/*get a new line*/
					newline_start = i;

					while( !newline(p[i]) &&  !end_of_string(p[i]) ) {
						i++;
					}
					
					/*now i  is equal to end of the line*/
					j = newline_start;

					if(';' != p[j]) /*skip over comment*/
					{
						while(j < i && p[j]!='=') {
							j++;
							if('=' == p[j]) {
								if(strncmp(key,p+newline_start,j-newline_start)==0)
								{
									/*find the key ok*/
									*key_s = newline_start;
									*key_e = j-1;

									*value_s = j+1;
									*value_e = i;

									return 0;
								}
							}
						}
					}

					i++;
				}
			}
		}
		else
		{
			i++;
		}
	}
	return -1;
}

/**
*@brief read string in initialization file\n
* retrieves a string from the specified section in an initialization file
*@param section [in] name of the section containing the key name
*@param key [in] name of the key pairs to value 
*@param value [in] pointer to the buffer that receives the retrieved string
*@param size [in] size of result's buffer 
*@return0 : read success; \n -1 : read fail
*/
int read_profile_string( const char *section, const char *key,char *value,int size) 
{
	int sec_s,sec_e,key_s,key_e, value_s, value_e;

	/*check parameters*/
	if(section == NULL || key == NULL || value == NULL || size < 0 )
	{
		return -1;
	}

	if(parse_file(section,key,filebuff,&sec_s,&sec_e,&key_s,&key_e,&value_s,&value_e)==-1)
	{
		printk("parse_file func error\n");
		return -1; /*not find the key*/
	}
	else
	{
		int cpcount = value_e -value_s;

		if( size-1 < cpcount)
		{
			cpcount =  size-1;
		}
	
		memset(value, 0, size);
		memcpy(value,filebuff+value_s, cpcount );
		value[cpcount] = '\0';

		return 0;
	}

	return 0;
}

以下是测试用的代码

int MTU;
int ETH1;
char mac[6]
char tmp[50];
	
if(load_ini_file()!=1)
	return -1;

memset(tmp,0,sizeof(tmp));
if(read_profile_string("GLOBA", "MTU", tmp, sizeof(tmp)) == -1)
{
	printk( KERN_EMERG "Read MTU error.\n");
	return -1;
}
MTU=atoi(name);

memset(tmp,0,sizeof(tmp));
if(read_profile_string("GLOBA", "Eth1", tmp, sizeof(tmp)) == -1)
{
	printk( KERN_EMERG "Read Eth1 error.\n");
	return -1;
}
ETH1=iptoint(tmp);

memset(tmp,0,sizeof(tmp));
if(read_profile_string(section, "mac", tmp, sizeof(tmp)) == -1)
{
	printk( KERN_EMERG "Read mac error.\n");
	break;
}
str2hex(tmp,mac,12);

调用这些测试代码需要以下几个转换方法

int atoi(const char *s)
{
    int i, n;
    
    n = 0;
    for(i = 0; s[i] >= '0' && s[i] <= '9'; ++i)
       n = 10*n + s[i] - '0';

    return (n);
}

char* strrev(char* szT)
{
	int i,j,k,t;
	char ch;
	if ( !szT )                 // 处理传入的空串.
		return "";
	i = strlen(szT);
	t = !(i%2)? 1 : 0;      // 检查串长度.
	for(j = i-1 , k = 0 ; j > (i/2 -t) ; j-- )
	{
		ch  = szT[j];
		szT[j]   = szT[k];
		szT[k++] = ch;
	}
	return szT;
}

char* itoa(int value, char*  str, int radix)
{
	int  rem = 0;
	int  pos = 0;
	char ch  = '!' ;
	do
	{
		rem    = value % radix ;
		value /= radix;
		if ( 16 == radix )
		{
			if( rem >= 10 && rem <= 15 )
			{
				switch( rem )
				{
					case 10:
					ch = 'a' ;
					break;
					case 11:
					ch ='b' ;
					break;
					case 12:
					ch = 'c' ;
					break;
					case 13:
					ch ='d' ;
					break;
					case 14:
					ch = 'e' ;
					break;
					case 15:
					ch ='f' ;
					break;
				}
			}
		}
		if( '!' == ch )
		{
			str[pos++] = (char) ( rem + 0x30 );
		}
		else
		{
			str[pos++] = ch ;
		}
	}while( value != 0 );
	str[pos] = '\0' ;
	return strrev(str);
}

// 将16进制的字符串转换成数组
int str2hex(const char* pstrin,unsigned char* pstrout,int len)
{
	int i = 0;
	if(len & 1)
		return -1;

	for(; i < len; i++)
	{
		if(pstrin[i] >= '0' && pstrin[i] <= '9')
		{
			if(i & 1)
				pstrout[i>>1] |= ((pstrin[i] - '0') & 0x0f);
			else
				pstrout[i>>1] = (pstrin[i] - '0') << 4;			
		}
		else if(pstrin[i] >= 'A' && pstrin[i] <= 'F')
		{
			if(i & 1)
				pstrout[i>>1] |= ((pstrin[i] - 0x37) & 0x0f); 
			else
				pstrout[i>>1] = (pstrin[i] - 0x37) << 4;
		}
		else if(pstrin[i] >= 'a' && pstrin[i] <= 'f')
		{
			if(i & 1)
				pstrout[i>>1] |= ((pstrin[i] - 0x57) & 0x0f);
			else
				pstrout[i>>1] = (pstrin[i] - 0x57) << 4;
		}
		else
			return -1;		
		
	}
	return 0;
}

// 将字符串格式类似于“192.168.0.1”的ip地址转换成整形数
int iptoint(const char *ip)
{
	const char *ptmp1 = ip;
	unsigned char actmp[4] ={0};
	int iVal = 0,j=0,iIP =0,c = 0;
	int m= 0,k =0;

	memset(actmp,0,sizeof(actmp));
	while( *ptmp1 != '\0')
	{
		if(j >= 4)
			return -1;

		if((*ptmp1 < '0' || *ptmp1 > '9') && (*ptmp1!=0x2e))
			return -1;

		actmp[j++] = *ptmp1-0x30;		

		if(*ptmp1++ == '.' || (*ptmp1 == '\0' && c == 3))
		{
			if(*ptmp1 != '\0')
			{
				 for( m= 1;m < j ; m++)
				 {
					iVal = iVal*10 + actmp[m-1];
				 }
			}
			else
			{
				 for( k = 0;k <j ; k++)
				 {
					iVal = iVal*10 + actmp[k];
				 }
			}
			
			if(iVal > 255)
				return -1;

			((unsigned char*)&iIP)[c] = iVal;

			 memset(actmp,0,sizeof(actmp));
			 j = 0;
			 iVal =0;
			 c++;
		}

	}

	if(c== 4 && j == 0 && (actmp[0] ^ 0x80))
		return iIP;
	else
		return -1;
}