复制代码 代码如下:
#include"apue.h"

int userlogin(struct passwd **);

int main()
{
int ret,i=0;
long ret_cwd;
struct passwd *pw;
char buf[128],hostname[16],usercwd[128];
char *ptmp1;

do{
ret = userlogin(&pw);
}while(ret != 1);

getchar();

while(1){
//to gethostname
if(gethostname(buf,128)!=0){
perror("gethostname()");
return 0;
}
//truncate hostname untill '.'
while(buf[i]!='.'){
hostname[i++] = buf[i];
}
i = 0;
//if the user is 'root' the symbol is '#'
//else '$'
//and the current work path is truncated from the last '/' to the end
ret_cwd = (long)getcwd(usercwd,128);
if(strcmp(usercwd,pw->pw_dir)==0){
ret = sprintf(usercwd,"~\0",NULL);
}
else if(strcmp(usercwd,"/")!=0){
ptmp1 = strrchr(usercwd,'/');
sprintf(usercwd,"%s",ptmp1+1);
}
if(strcmp(pw->pw_name,"root")==0){
sprintf(buf,"*[%s@%s %s]# ",
pw->pw_name,hostname,usercwd);
}
else{
sprintf(buf,"*[%s@%s %s]$ ",
pw->pw_name,hostname,usercwd);
}
//command
ssize_t g_ret,len;
char *line = NULL,*s_ret,*ptr=NULL;
int con_cd=0;

fprintf(stderr,"%s",buf);

g_ret = getline(&line,&len,stdin);

line[strlen(line)-1] = '\0';
if(strcmp(line,"exit")==0){
exit(-1);
}
ptr = line;
s_ret = line;

system(line);
while(ptr!=NULL){
s_ret = (char *)strsep(&ptr," ");

if(strcmp(s_ret,"cd") == 0){
con_cd=1;
continue;
}
else if(con_cd == 1){
chdir(s_ret);
}
}
}
return 0;
}

//login function
int userlogin(struct passwd **pw)
{
char name[32],*passwd,*pret;
struct spwd *sp;

printf("login:");
fflush(stdout);
scanf("%s",name);

passwd = getpass("password:");

sp = getspnam(name);
if(sp == NULL){
fprintf(stdout,"no is user![%s]\n",name);
return 0;
}

pret = crypt(passwd,sp->sp_pwdp);

if(pret == NULL){
fprintf(stdout,"crypt(%s)\n",name);
return 0;
}

if(strcmp(pret,sp->sp_pwdp) == 0){
printf("login successful!\n");
}
else{
fprintf(stdout,"passwd is error!\n");
return 0;
}

*pw = getpwnam(name);
if(*pw == NULL){
printf("getpwnam(%s) error\n",name);
return 0;
}

return 1;

}