int printf(char *fmt , ...){
char str[50];
int index_f = 0; //跟随fmt赋值入str
int index_s = 0; //跟随着str的位置标示
int insert = 0; //当有参数比如整数出现时转化为字符串，并记录插入的字符个数
int start = 0;
int *p = &fmt;
p += 1;
while(1){
if(*(fmt + index_f) == 0x00){
str[index_s] = 0x00;
sprintk(str + start);
break;
}
if(*(fmt + index_f) == '%'){
index_f++;
switch(*(fmt + index_f)){
case 'd':
insert = itoa(*p , str + index_s); //将参数(整形)转化为字符串，并放入以str+index_s开头的串中
index_s += insert; //index_s需要加上插入的字符串个数insert
p += 1; //p指向下一个参数地址
index_f++; //index_f指向fmt的下一个字符
break;
case 'c':
str[index_s] = (char)*p;
p +=1;
index_f++;
index_s++;
break;
case 's':
insert = strncpy(str + index_s , (char *)*p , 0); //*p为参数字符串的首地址
index_s += insert;
p += 1;
index_f++;
break;
default:
break;
}
continue;
}
if(*(fmt + index_f) == '/'){
index_f++;
switch(*(fmt + index_f)){
case 'n':
str[index_s] = 0x00; //出现转义字符时，输出之前的部分
sprintk(str + start);
index_s++; //重新设置index_s为输出后的部分
start = index_s; //start也要做相应设定
print_ctrl(); //输出回车
index_f++;
break;
case 't':
break;
default:
break;
}
continue;
}
str[index_s] = *(fmt + index_f);
index_f++;
index_s++;
}
return index_s;
}
static int print_ctrl2(const struct sockaddr_nl *who,
struct nlmsghdr *n, void *arg)
{
return print_ctrl(who, NULL, n, arg);
}
static int ctrl_list(int cmd, int argc, char **argv)
{
struct rtnl_handle rth;
struct nlmsghdr *nlh;
struct genlmsghdr *ghdr;
int ret = -1;
char d[GENL_NAMSIZ];
struct {
struct nlmsghdr n;
char buf[4096];
} req;
memset(&req, 0, sizeof(req));
nlh = &req.n;
nlh->nlmsg_len = NLMSG_LENGTH(GENL_HDRLEN);
nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
nlh->nlmsg_type = GENL_ID_CTRL;
ghdr = NLMSG_DATA(&req.n);
ghdr->cmd = CTRL_CMD_GETFAMILY;
if (rtnl_open_byproto(&rth, 0, NETLINK_GENERIC) < 0) {
fprintf(stderr, "Cannot open generic netlink socket\n");
exit(1);
}
if (cmd == CTRL_CMD_GETFAMILY) {
if (argc != 2) {
fprintf(stderr, "Wrong number of params\n");
return -1;
}
if (matches(*argv, "name") == 0) {
NEXT_ARG();
strncpy(d, *argv, sizeof (d) - 1);
addattr_l(nlh, 128, CTRL_ATTR_FAMILY_NAME,
d, strlen(d) + 1);
} else if (matches(*argv, "id") == 0) {
__u16 id;
NEXT_ARG();
if (get_u16(&id, *argv, 0)) {
fprintf(stderr, "Illegal \"id\"\n");
goto ctrl_done;
}
addattr_l(nlh, 128, CTRL_ATTR_FAMILY_ID, &id, 2);
} else {
fprintf(stderr, "Wrong params\n");
goto ctrl_done;
}
if (rtnl_talk(&rth, nlh, 0, 0, nlh) < 0) {
fprintf(stderr, "Error talking to the kernel\n");
goto ctrl_done;
}
if (print_ctrl(NULL, nlh, (void *) stdout) < 0) {
fprintf(stderr, "Dump terminated\n");
goto ctrl_done;
}
}
if (cmd == CTRL_CMD_UNSPEC) {
nlh->nlmsg_flags = NLM_F_ROOT|NLM_F_MATCH|NLM_F_REQUEST;
nlh->nlmsg_seq = rth.dump = ++rth.seq;
if (rtnl_send(&rth, nlh, nlh->nlmsg_len) < 0) {
perror("Failed to send dump request\n");
goto ctrl_done;
}
rtnl_dump_filter(&rth, print_ctrl, stdout);
}
ret = 0;
ctrl_done:
rtnl_close(&rth);
return ret;
}
