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#include <sys/socket.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <ctype.h>
#include <stdbool.h>
#include "util.h"
/*
* CONNECT MSG: "connect NAME"
* SEND MSG: "msg XXXXX CONTENTS TIME"
* VALID MSG: 0
* INVALID MSG: 1
*/
typedef struct client {
char *name;
int fd;
bool connected;
} client;
typedef struct msg {
client *sender;
char *contents;
time_t time;
} msg;
FILE *fout;
int VALID = 0;
int INVALID = 1;
static int
init_daemon(int port) {
int s = socket(AF_INET, SOCK_STREAM, 0);
struct sockaddr_in addr = {AF_INET, htons(port), INADDR_ANY};
if (bind(s, (struct sockaddr *)&addr, sizeof(addr)))
error("Failed to bind");
int flags = 10;
if (setsockopt(s, SOL_TCP, TCP_KEEPIDLE, (void *)&flags, sizeof(flags)))
error("Couldn't set socket opts");
flags = 5;
if (setsockopt(s, SOL_TCP, TCP_KEEPCNT, (void *)&flags, sizeof(flags)))
error("Couldn't set socket opts");
flags = 5;
if (setsockopt(s, SOL_TCP, TCP_KEEPINTVL, (void *)&flags, sizeof(flags)))
error("Couldn't set socket opts");
listen(s, 10);
return s;
}
static void
stop_daemon(int s) {
close(s);
}
static client *
accept_client(int s) {
client *c = malloc(sizeof(client));
c->fd = accept(s, NULL, NULL);
char buf[256] = {0};
char *Pbuf = buf;
int n = recv(c->fd, buf, 256, 0);
if (n <= 0) {
warn("Client hungup");
close(c->fd);
return NULL;
}
if (n <= 8) {
warn("Malformed connect msg");
close(c->fd);
return NULL;
}
if (memcmp(buf, "connect ", 8) != 0) {
warn("Malformed connect msg");
close(c->fd);
return NULL;
}
Pbuf += 8;
c->name = strdup(Pbuf);
c->connected = true;
return c;
}
static void
close_client(client *c) {
close(c->fd);
free(c->name);
free(c);
}
static msg*
recv_msg(client *c) {
char buf[11] = {0};
char *Pbuf = buf + 4;
int n = recv(c->fd, buf, 10, 0);
if (n <= 0) {
warn("Client hungup");
close(c->fd);
c->connected = false;
return NULL;
}
if (n < 10) {
warn("Malformed msg msg");
send(c->fd, &INVALID, sizeof(int), 0);
return NULL;
}
if (memcmp(buf, "msg ", 4) != 0) {
warn("Malformed msg msg");
send(c->fd, &INVALID, sizeof(int), 0);
return NULL;
}
for (int i = 4; buf[i] != 0 && i < 9; i++) {
if (!isdigit(buf[i])) {
warn("Malformed msg msg");
send(c->fd, &INVALID, sizeof(int), 0);
return NULL;
}
}
int len = atoi(Pbuf);
char *contents = malloc(len);
memset(contents, 0, len);
n = recv(c->fd, contents, len, 0);
if (n <= 0) {
warn("Client hungup");
c->connected = false;
close(c->fd);
return NULL;
}
msg *m = malloc(sizeof(msg));
m->sender = c;
m->contents = contents;
time_t t;
n = recv(c->fd, &t, sizeof(time_t), 0);
if (n <= 0) {
warn("Client hungup");
c->connected = false;
close(c->fd);
return NULL;
}
m->time = t;
send(c->fd, &VALID, sizeof(int), 0);
return m;
}
static void
free_msg(msg *m) {
free(m->contents);
free(m);
}
static void
msg_loop(client *c) {
msg *m;
while (c->connected && (m = recv_msg(c))) {
fprintf(fout, "%lld:%s:%s\n", m->time, m->sender->name, m->contents);
free_msg(m);
}
close_client(c);
exit(0);
}
int
main(int argc, char **argv) {
char *out;
if (argc <= 1)
out = "/dev/stdout";
else
out = argv[1];
if (!(fout = fopen(out, "w")))
error("Couldn't open outfile");
int s = init_daemon(1543);
pid_t pid;
for (;;) {
client *c = accept_client(s);
if ((pid = fork()) == 0)
msg_loop(c);
else
continue;
}
stop_daemon(s);
}
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