init commit of talk and talk serverHEADmaster

1 files changed, 177 insertions, 0 deletions

diff --git a/talkserver.c b/talkserver.c
new file mode 100644
index 0000000..f96a8b7
--- /dev/null
+++ b/talkserver.c
@@ -0,0 +1,177 @@
+#include <unistd.h>
+#include <stdio.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <openssl/sha.h>
+
+#include "talk.h"
+#include "util.h"
+
+#define PORT 231
+
+#define USERSDIR "./users/"
+#define PASSWORDFILE "./passwd"
+
+static int initsocket(struct sockaddr_in address, socklen_t len){
+	int s;
+	if ((s = socket(AF_INET, SOCK_STREAM, 0)) == -1){
+		perror("socket");
+		return -1;
+	}
+	if ((bind(s, (struct sockaddr *)&address, len)) != 0) {
+		perror("bind");
+		return -1;	
+	}
+
+	listen(s, 10);
+	return s;
+}
+
+static bool checkpasswd(char *username, char *password) {
+	char *passwdline, *tok;
+	unsigned char hash[SHA_DIGEST_LENGTH];
+	FILE *f = fopen(PASSWORDFILE, "r");
+
+	while ((passwdline = readupto(f, ':')) != NULL){
+		tok = readnchars(f, 20);
+		if (strcmp(passwdline, username) == 0){
+			SHA1((unsigned char *)password, 30, hash);
+			if (memcmp((char *)hash, tok, 20) == 0){
+				free(tok);
+				free(passwdline);
+				return true;
+			} else {
+				free(tok);
+				free(passwdline);
+				return false;
+			}
+		}
+		free(tok);
+		free(passwdline);
+	}
+	return false;
+}
+
+int main(){
+	struct sockaddr_in address;
+	address.sin_family = AF_INET;
+	address.sin_addr.s_addr = INADDR_ANY;
+	address.sin_port = htons(PORT);
+	socklen_t len = sizeof(address);
+
+	int s;
+	if ((s = initsocket(address, len)) < 0) return s;
+
+	int client;
+	for (;;) {
+		if ((client = accept(s, (struct sockaddr *)&address, &len)) == -1){
+			perror("accept");
+			return 1;
+		}
+
+		int size = sizeof(packet);
+		packet *buf = malloc(size);
+		recv(client, buf, size, 0);
+
+		char *userdir, *tok, *passwdline, *msg;
+		unsigned char hash1[SHA_DIGEST_LENGTH], hash2[SHA_DIGEST_LENGTH];
+		FILE *f, *fmsg;
+		int len;
+
+		switch (buf->type){
+			case MSG:
+				buf->msg = calloc(1, buf->msglen);
+				recv(client, buf->msg, buf->msglen, 0);
+				
+				if (checkpasswd(buf->username, buf->password) == true){
+					if (buf->msg == NULL || strlen(buf->msg) == 0) {
+						buf->msg = "(null)";
+						goto end;
+					}
+					userdir = malloc(80);
+					snprintf(userdir, 80, "%s%s/%s", USERSDIR, buf->recipient, buf->username);
+					fmsg = fopen(userdir, "a+");
+					if (fmsg == NULL) goto nosuchuser;
+					fprintf(fmsg, "%s\n", buf->msg);
+					fclose(fmsg);
+					free(userdir);
+					goto end;
+				} else {
+					buf->type = PASSAUTHFAIL;
+					goto end;	
+				}
+
+nosuchuser:
+				buf->type = NOSUCHUSER;
+end:
+				send(client, buf, size, 0);
+				break;
+			case GET:
+				if (checkpasswd(buf->username, buf->password) == true){
+					len = 128;
+					userdir = calloc(1, len);
+					snprintf(userdir, len, "%s%s/%s", USERSDIR, buf->username, buf->recipient);
+
+					f = fopen(userdir, "r");
+					if (f == NULL) {
+						buf->type = NEVERMSGED;
+						send(client, buf, size, 0);
+						break;
+					}
+
+					msg = readupto(f, EOF);
+					buf->msg = msg;
+					buf->msglen = strlen(msg);
+					send(client, buf, size, 0);
+					send(client, buf->msg, buf->msglen, 0);
+
+					remove(userdir);	
+
+					free(userdir);
+					userdir = NULL;
+				} else {
+					buf->type = PASSAUTHFAIL;
+				}
+				send(client, buf, size, 0);
+				
+				break;
+			case NEWUSER:
+				userdir = calloc(1, strlen(USERSDIR) + strlen(buf->username));
+				strcat(userdir, USERSDIR);
+				strcat(userdir, buf->username);
+
+				if (mkdir(userdir, 0777) == -1) {
+					buf->type = USERMAKEERROR;
+				} else {
+					buf->type = NEWUSER;
+					SHA1((unsigned char *)buf->password, 30, hash1);
+					f = fopen(PASSWORDFILE, "a+");
+					if (f == NULL) exit(1);
+					fprintf(f, "%s:%s\n", buf->username, hash1);
+					fclose(f);
+					free(userdir);
+					userdir = NULL;
+				}
+				send(client, buf, size, 0);
+				break;
+			default:
+				buf->type = UNKNOWNCMD;
+				send(client, buf, size, 0);
+				break;
+		}
+
+		free(buf->msg);
+		free(buf);
+
+		close(client);
+	}
+
+
+	close(s);
+
+	return 0;
+}