[LCP]Small question about a program...

[Stratis Aftousmis]

#define _XOPEN_SOURCE
#include <unistd.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include "/Source/str.h"

int set_term()
{
	if (system("stty -echo") == -1) 
		return -1;
	else
		return 0;
}

int reset_term()
{
	if (system("stty echo") == -1)  
		return -1;
	else
		return 0;
}
	
int main()
{
	char buff[1024], pass[100], string[100], salt[100], user[100], temp[100];
	FILE *file;
	if ((file = fopen("/etc/shadow", "r")) == NULL) {
		fprintf(stderr, "fopen: Failed.\n");
		exit(1);
	}
	if (fread(buff, 1 , sizeof(buff), file) == 0) {
		fprintf(stderr, "fread: Failed.\n");
		exit(1);
	}
	if (substr(buff, getlogin(), "\n", temp) == NULL) {
		fprintf(stderr, "substr: Failed.\n");
		exit(1);
	}
	if (substr(temp, "$", ":", pass) == NULL) {
		fprintf(stderr, "substr: Failed.\n");
		exit(1);
	}
	if (!strncpy(salt, pass, sizeof(salt))) {
		fprintf(stderr, "strncpy: Failed.\n");
		exit(1);
	}
	fprintf(stdout, "Please enter your password.\n");
	fprintf(stdout, "Password:");
	if (set_term() == -1) {
		fprintf(stderr, "set_term: Failed.\n");
		exit(1);
	}
	if (nlnuke(user, sizeof(user)) == -1) {
		reset_term();
		fprintf(stderr, "nlnuke: Failed.\n");
		exit(1);	
	}
	if (reset_term() == -1) {
		fprintf(stderr, "reset_term: Failed.\n");
		exit(1);
	}
	if (!strncpy(string, crypt(user, salt), sizeof(string))) {
		fprintf(stderr, "strncpy: Failed.\n");
		exit(1);
	}
	if (strcmp(pass, string) != 0) {
		fprintf(stderr, "\nlogin: Failed.\n");
		exit(1);
	}
	if (fclose(file) == EOF) {
		fprintf(stderr, "fclose: Failed.\n");
		exit(1);
	}
	fprintf(stdout, "\n%s logged in.\n", getlogin());
	return 0;
}

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Used with an include of my own making, 'str.h'.

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

/*C string manipulation functions:
Copyright (C) 2004-2010 stratis aftousmis E-mail: karen4253 at sbcglobal.net

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.*/

#include <strings.h>
#include <stdio.h>

char *substr(char *buf, const char *start, const char *end, char *result)
{	
	char *buff;
	if ((buff = strstr(buf, start)) == NULL) 
		return NULL;
	while (*buff != *end && *buff != '\0')
		*result++ = *buff++;
	*result = '\0';
	return result;
}

int nlnuke(char st[], size_t in)
{
        int i = 0;
        char s[in];
        if (fgets(s, sizeof(s), stdin) == NULL) 
                return -1;
        while (s[i] != '\n' && s[i] != '\0') {
		st[i] = s[i];
                i++;
	}
        st[i] = '\0';
        return 0;
}

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

First post, Hello! ;)

I just wanted to show off one of my programs, get any kind of input available. :)

Thank you. 

Stratis