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login.c
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login.c
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#include "types.h"
#include "stat.h"
#include "user.h"
#define passwdFile "/passwd.txt"
#define maxLength 100
int contains(char *str, char *pattern){
int i=0,j=0;
int sizeStr = strlen(str) - 1;
int sizePattern = strlen(pattern) - 1;
while(i<sizePattern && j < sizeStr && pattern[i] != str[j]){
j++;
}
if(j == sizeStr){
return 0;
}
while(i<sizePattern && j < sizeStr && pattern[i] == str[j]){
i++;
j++;
}
if(i == sizePattern){
return 1;
} else{
return 0;
}
}
int readLine(int fd, char *buf, int size){
int i = 0, n = 0;
char c;
while(read(fd, &c, 1) > 0)
{
n++;
if(c != '\n')
{
buf[i] = c;
i++;
if(i == size -1)
{
break;
}
} else
{
break;
}
}
buf[i] = '\0';
return n;
}
int main(int argc, char *argv[])
{
int fd;
char record[maxLength];
char userName[maxLength];
char userPassword[maxLength];
int n, pid, wpid;
char *shArgv[] = { "sh", 0 };
//printf(1, "userName = %s, userPassword = %s, userName, userPassword");
while(1)
{
printf(1, "login: ");
memset(userName, 0, sizeof(userName));
read(0, userName, sizeof(userName));
userName[strlen(userName)-1] = ':';
printf(1, "password: ");
memset(userPassword, 0, sizeof(userPassword));
read(0, userPassword, sizeof(userPassword));
userPassword[strlen(userPassword)-1] = ':';
userPassword[strlen(userPassword)] = '\0';
fd = open(passwdFile, 0);
while((n=readLine(fd, record, sizeof(record)))>0)
{
if(contains(record, userPassword) && contains(record, userName))
{
pid = fork();
if(pid < 0)
{
printf(1, "login: fork failed\n");
exit();
}
if(pid == 0)
{
exec("sh", shArgv);
printf(1, "login: exec sh failed\n");
exit();
}
while((wpid=wait()) >= 0 && wpid != pid)
printf(1, "zombie!\n");
break;
}
}
}
close(fd);
exit();
}