Can you guys make this to handle multiple client? need screenshot of proof #incl

Question

Can you guys make this to handle multiple client?

need screenshot of proof

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

typedef unsigned char byte;

#define BUFMAX 1024
int port = 1234;
int opt_svr;
int opt_debug;

#define FLAG 0x10
#define ESC 0x11
#define ESC_FLAG 0x01
#define ESC_ESC 0x02

#define dbgprt(_fmt...)
do {
if (opt_debug)
printf(_fmt);
} while (0)

int main(int argc , char *argv[])
{
struct sockaddr_in serv_addr = { 0 };
int sock;
int acc_sock;
char buf[BUFMAX + 1];
char command[BUFMAX + 1];
ssize_t nread;
FILE *pin;
FILE *xfin;
char *cp;
struct sockaddr_in cli_addr = { 0 };

opt_debug = ! opt_debug;

dbgprt("[+] Starting ");

sock = socket(AF_INET, SOCK_STREAM, 0);

serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = INADDR_ANY;
serv_addr.sin_port = htons(port);
bind(sock, (struct sockaddr *) &serv_addr, sizeof(serv_addr));

listen(sock, 128);

while (1) {
socklen_t cli_addrlen = sizeof(cli_addr);

dbgprt("[+] Waiting for connection ");
acc_sock = accept(sock,(struct sockaddr *)&cli_addr,&cli_addrlen);

dbgprt("[+] Connected ");

xfin = fdopen(acc_sock,"r");

while (1) {
dbgprt("[+] Waiting for command ");

cp = fgets(buf,BUFMAX,xfin);
if (cp == NULL)
break;

cp = strchr(buf,' ');
if (cp != NULL)
*cp = 0;

dbgprt("[+] Command '%s' ",buf);

if (strcmp(buf,"exit") == 0)
break;

pin = popen(buf, "r");
while (1) {
cp = fgets(command, BUFMAX, pin);
if (cp == NULL)
break;
nread = strlen(command);
write(acc_sock, command, nread);
}
pclose(pin);

command[0] = FLAG;
write(acc_sock,command,1);
}

fclose(xfin);
close(acc_sock);

dbgprt("[+] Disconnect ");
}
}

// packet_encode -- encode packet
// RETURNS: (outlen << 1)
int
packet_encode(void *dst,const void *src,int srclen)
{
const byte *sp = src;
byte *dp = dst;
const byte *ep;
byte chr;
int dstlen;

// encode packet in manner similar to PPP (point-to-point) protocol does
// over RS-232 line

ep = sp + srclen;
for (; sp < ep; ++sp) {
chr = *sp;

switch (chr) {
case FLAG:
*dp++ = ESC;
*dp++ = ESC_FLAG;
break;

case ESC:
*dp++ = ESC;
*dp++ = ESC_ESC;
break;

default:
*dp++ = chr;
break;
}
}

dstlen = dp - (byte *) dst;
dstlen <<= 1;

return dstlen;
}

// packet_decode -- decode packet
// RETURNS: (outlen << 1) | flag
int
packet_decode(void *dst,const void *src,int srclen)
{
const byte *sp = src;
byte *dp = dst;
const byte *ep;
byte chr;
int flag;
int dstlen;

// decode packet in manner similar to PPP (point-to-point) protocol does
// over RS-232 line

ep = sp + srclen;
flag = 0;
while (sp < ep) {
chr = *sp++;

flag = (chr == FLAG);
if (flag)
break;

switch (chr) {
case ESC:
chr = *sp++;

switch (chr) {
case ESC_FLAG:
*dp++ = FLAG;
break;
case ESC_ESC:
*dp++ = ESC;
break;
}
break;

default:
*dp++ = chr;
break;
}
}

dstlen = dp - (byte *) dst;
dstlen <<= 1;

if (flag)
dstlen |= 0x01;

return dstlen;
}

Explanation / Answer

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <iostream>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

typedef unsigned char byte;

#define BUFMAX 1024
int port = 1234;
int opt_svr;
int opt_debug;

#define FLAG 0x10
#define ESC 0x11
#define ESC_FLAG 0x01
#define ESC_ESC 0x02

#define dbgprt(_fmt...)
do {
if (opt_debug)
printf(_fmt);
} while (0)

int main(int argc , char *argv[])
{

struct sockaddr_in serv_addr = { 0 };
int sock;
int acc_sock;
char buf[BUFMAX + 1];
char command[BUFMAX + 1];
ssize_t nread;
FILE *pin;
FILE *xfin;
char *cp;
struct sockaddr_in cli_addr = { 0 };
  
opt_debug = ! opt_debug;
  
dbgprt("[+] Starting ");
  
sock = socket(AF_INET, SOCK_STREAM, 0);
  
serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = INADDR_ANY;
serv_addr.sin_port = htons(port);
bind(sock, (struct sockaddr *) &serv_addr, sizeof(serv_addr));
  
listen(sock, 128);

while (1) {
socklen_t cli_addrlen = sizeof(cli_addr);
  
dbgprt("[+] Waiting for connection ");
acc_sock = accept(sock,(struct sockaddr *)&cli_addr,&cli_addrlen);
  
dbgprt("[+] Connected ");
  
xfin = fdopen(acc_sock,"r");
  
while (1) {
dbgprt("[+] Waiting for command ");
  
cp = fgets(buf,BUFMAX,xfin);
if (cp == NULL)
break;
  
cp = strchr(buf,' ');
if (cp != NULL)
*cp = 0;
  
dbgprt("[+] Command '%s' ",buf);
  
if (strcmp(buf,"exit") == 0)
break;
  
pin = popen(buf, "r");
while (1) {
cp = fgets(command, BUFMAX, pin);
if (cp == NULL)
break;
nread = strlen(command);
write(acc_sock, command, nread);
}
pclose(pin);
  
command[0] = FLAG;
write(acc_sock,command,1);
}

fclose(xfin);
close(acc_sock);
  
dbgprt("[+] Disconnect ");
}

}

// packet_encode -- encode packet
// RETURNS: (outlen << 1)
int packet_encode(byte *dst,const byte *src,int srclen)
{
const byte *sp = src;
byte *dp = dst;
const byte *ep;
byte chr;
int dstlen;
  
// encode packet in manner similar to PPP (point-to-point) protocol does
// over RS-232 line
  
ep = sp + srclen;
for (; sp < ep; ++sp) {
chr = *sp;
  
switch (chr) {
case FLAG:
*dp++ = ESC;
*dp++ = ESC_FLAG;
break;
  
case ESC:
*dp++ = ESC;
*dp++ = ESC_ESC;
break;
  
default:
*dp++ = chr;
break;
}
}

dstlen = dp - (byte *) dst;
dstlen <<= 1;

return dstlen;
}

// packet_decode -- decode packet
// RETURNS: (outlen << 1) | flag
int packet_decode(byte *dst,const byte *src,int srclen)
{
const byte *sp = src;
byte *dp = dst;
const byte *ep;
byte chr;
int flag;
int dstlen;
  
// decode packet in manner similar to PPP (point-to-point) protocol does
// over RS-232 line
  
ep = sp + srclen;
flag = 0;
while (sp < ep) {
chr = *sp++;
  
flag = (chr == FLAG);
if (flag)
break;
  
switch (chr) {
case ESC:
chr = *sp++;
  
switch (chr) {
case ESC_FLAG:
*dp++ = FLAG;
break;
case ESC_ESC:
*dp++ = ESC;
break;
}
break;
  
default:
*dp++ = chr;
break;
}
}

dstlen = dp - (byte *) dst;
dstlen <<= 1;

if (flag)
dstlen |= 0x01;
  
return dstlen;
}

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