randloc.c

#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <unistd.h>
#include <string.h>
#include <stdio.h>
#include <fcntl.h>
#include <time.h>
#include <stdlib.h>
#include <pthread.h>

#define PORT 8000
#define OKMSG "HTTP/1.0 302 Found\r\nContent-length: 0\r\nLocation: https://avatar.spacefox.fr/Renard-%d.png\r\n\r\n"
#define MAXAVATARNR 21
#define MAXAVATARLEN 2
#define OUTLEN strlen(OKMSG)-2+MAXAVATARLEN

typedef struct {
	int sock;
	int rand;
} args_t;

void cleanup(void *a) {
	close(((args_t*)a)->sock);
	free(a);
}

void* handle_req(void *a) {
	args_t *b=(args_t*)a;
	pthread_cleanup_push(cleanup,b);
	char out[OUTLEN];
	int len=sprintf(out, OKMSG, b->rand);
	write(b->sock, out, len);
	pthread_cleanup_pop(1);
	return(NULL);
}

args_t *a;

int  main(int argc, char **argv) {
	struct sockaddr_in addr;
	int s=socket(AF_INET,SOCK_STREAM|SOCK_CLOEXEC,0);
	int s2;
	srand48(time(NULL));
	if(s<0) { perror("socket"); exit(1); }
	setsockopt(s,SOL_SOCKET,SO_REUSEADDR,&(int){1},sizeof(int));
	addr.sin_family=AF_INET;
	addr.sin_port=htons(PORT);
	addr.sin_addr.s_addr=htonl(INADDR_LOOPBACK);
	bind(s,(struct sockaddr*)&addr,sizeof(struct sockaddr_in));
	if(listen(s,512)<0) { perror("listen"); exit(1); }
	while((s2=accept(s,NULL,0))) {
		a=malloc(sizeof(args_t));
		a->sock=s2;
		a->rand=1+drand48()*MAXAVATARNR;
		pthread_t x;
		pthread_create(&x,NULL,handle_req,a);
		pthread_detach(x);
	}
	return(0);
}