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/*
* Dummy server sending alternating bytes to all clients.
*
* This is used by the face manager to illustrate the creation of interfaces
* using unix domains that sets a face up and down.
*/
#include <arpa/inet.h> // inet_ntop
#include <errno.h> // EINTR,. ..
#include <netinet/in.h> // INET_ADDRSTRLEN, INET6_ADDRSTRLEN
#include <stdio.h>
#include <inttypes.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <sys/timerfd.h>
#include <sys/un.h> // sockaddr_un
#include <unistd.h> // fcntl
#include <fcntl.h> // fcntl
/**
* \brief Default unix socket path (the leading \0 means using the abstract
* namespace instead of the filesystem).
*/
#define UNIX_PATH "\0updownsrv"
/**
* \brief Default interval (in seconds) between timer events */
#define DEFAULT_INTERVAL 100000
/**
* \brief Maximum allowed number of connected clients
*/
#define MAX_CLIENTS 5
/**
* \brief Maximum backlog of listening unix socket
*/
#define LISTEN_BACKLOG MAX_CLIENTS
/**
* \brief Creates a unix server socket
* \param [in] path - string representing the path on which to listen for
* connections
* \return int - fd associated to the socket
*/
int
create_unix_server(char * path)
{
struct sockaddr_un addr;
int fd;
fd = socket(AF_UNIX, SOCK_STREAM, 0);
if (fd == -1) {
perror("socket error");
return -1;
}
if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) {
perror("fcntl");
return -1;
}
memset(&addr, 0, sizeof(addr));
addr.sun_family = AF_UNIX;
if (*path == '\0') {
*addr.sun_path = '\0';
strncpy(addr.sun_path+1, path+1, sizeof(addr.sun_path)-2);
} else {
strncpy(addr.sun_path, path, sizeof(addr.sun_path)-1);
unlink(path);
}
if (bind(fd, (struct sockaddr*)&addr, sizeof(addr)) == -1) {
perror("bind error");
return -1;
}
if (listen(fd, LISTEN_BACKLOG) == -1) {
perror("listen error");
return -1;
}
return fd;
}
/**
* \brief Main function
*/
int main() {
int fd, tfd;
int rc;
/* Alternating state of the server : 0 / 1 */
unsigned state = 0;
/*
* This server has to send a signal to all connected clients at periodic
* intervals. Since we don't expect a large number of connected clients for
* such a simple program, we simply use a statically allocated array.
*/
int clients[MAX_CLIENTS];
size_t num_clients = 0;
fd_set active_fd_set, read_fd_set;
FD_ZERO (&active_fd_set);
/* Create listening unix socket */
fd = create_unix_server(UNIX_PATH);
if (fd < 0)
exit(EXIT_FAILURE);
FD_SET (fd, &active_fd_set);
/* Create timer */
tfd = timerfd_create(CLOCK_MONOTONIC, 0);
if (tfd == -1) {
perror("timer error");
exit(EXIT_FAILURE);
}
if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) {
perror("fcntl");
exit(EXIT_FAILURE);
}
FD_SET (tfd, &active_fd_set);
struct itimerspec ts = {
.it_interval = {
.tv_sec = DEFAULT_INTERVAL,
.tv_nsec = 0,
},
.it_value = {
.tv_sec = DEFAULT_INTERVAL,
.tv_nsec = 0,
}
};
rc = timerfd_settime(tfd, 0, &ts, NULL);
if (rc == -1) {
perror("timerfd_settime");
exit(EXIT_FAILURE);
}
printf("Waiting for clients...\n");
for(;;) {
/* Block until input arrives on one or more active sockets. */
read_fd_set = active_fd_set;
rc = select (FD_SETSIZE, &read_fd_set, NULL, NULL, NULL);
if (rc < 0) {
if (rc == EINTR)
break;
perror("select");
exit (EXIT_FAILURE);
}
/* Service all the sockets with input pending. */
for (int i = 0; i < FD_SETSIZE; ++i) {
if (!FD_ISSET (i, &read_fd_set))
continue;
if (i == fd) {
/* Connection request on original socket. */
int client_fd = accept(fd, NULL, NULL);
if (client_fd < 0) {
perror("accept");
continue;
}
fprintf(stderr, "Server: connect from new client\n");
clients[num_clients++] = client_fd;
FD_SET(client_fd, &active_fd_set);
} else if (i == tfd) {
/* Timer event */
uint64_t res;
read(tfd, &res, sizeof(res));
// while (read(fd, &missed, sizeof(missed)) > 0)
// ;
for (unsigned j = 0; j < num_clients; j++) {
write(clients[j], state ? "\1" : "\0", 1);
}
printf("STATE=%d\n", state);
state = 1 - state;
} else {
char buf[1024];
rc = read(i, buf, sizeof(buf));
/* Client event : we close the connection on any event... */
for (unsigned j = 0; j < num_clients; j++) {
if (i == clients[j]) {
clients[j] = clients[num_clients--];
break;
}
}
close(i);
FD_CLR(i, &active_fd_set);
}
}
}
int ret = EXIT_SUCCESS;
/* Close all active client connections */
for (unsigned i = 0; i < num_clients; i++) {
rc = close(clients[i]);
if (rc == -1) {
perror("close");
ret = EXIT_FAILURE;
}
}
/* Close server */
rc = close(fd);
if (rc == -1) {
perror("close");
ret = EXIT_FAILURE;
}
/* Terminate timer */
ts.it_value.tv_sec = 0;
rc = timerfd_settime(tfd, 0, &ts, NULL);
if (rc == -1) {
perror("timerfd_settime");
exit(EXIT_FAILURE);
}
exit(ret);
}
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