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worker.c
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worker.c
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#include "seamless.h"
#include <arpa/inet.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/epoll.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/un.h>
#include <unistd.h>
#define MAX_EVENTS 100
// Externs.
extern int admin_fd;
extern int die_worker;
extern int server_fd;
// Forward decls.
int send_sockets();
void handle_sigusr1(int signum) {
printf("worker: handling sigusr1\n");
}
int run_worker() {
printf("worker: registering sigusr1 signal handler\n");
struct sigaction usr1;
memset(&usr1, 0, sizeof(struct sigaction));
usr1.sa_handler = handle_sigusr1;
int res_sig = sigaction(SIGUSR1, &usr1, NULL);
if (res_sig == -1) {
perror("worker: failed to register sigusr1 handler");
return -1;
}
printf("worker: creating epoll instance\n");
int poll_fd = epoll_create1(0);
if (poll_fd == -1) {
perror("worker: failed to create epoll instance");
return -1;
}
printf("worker: registering admin fd with epoll\n");
struct epoll_event admin_event;
memset(&admin_event, 0, sizeof(admin_event));
admin_event.events = EPOLLIN|EPOLLRDHUP|EPOLLET;
admin_event.data.fd = admin_fd;
int res_ctl = epoll_ctl(poll_fd, EPOLL_CTL_ADD, admin_fd, &admin_event);
if (res_ctl == -1) {
perror("worker: failed to add admin fd to epoll");
return -1;
}
printf("worker: registering server fd with epoll\n");
struct epoll_event server_event;
memset(&server_event, 0, sizeof(server_event));
server_event.events = EPOLLIN|EPOLLRDHUP|EPOLLET;
server_event.data.fd = server_fd;
res_ctl = epoll_ctl(poll_fd, EPOLL_CTL_ADD, server_fd, &server_event);
if (res_ctl == -1) {
perror("worker: failed to add server fd to epoll");
return -1;
}
// Poll for events until worker is told to die.
int conn_fd = 0;
while (!die_worker) {
struct epoll_event events[MAX_EVENTS];
int num_events = epoll_wait(poll_fd, events, MAX_EVENTS, POLL_TIMEOUT_MS);
if (num_events == 0) {
printf("worker: no events during waiting period\n");
continue;
}
while (num_events-- > 0) {
struct epoll_event event = events[num_events];
if (event.data.fd == admin_fd) {
printf("worker: handling admin event\n");
// Accept connection on admin socket.
struct sockaddr_in conn;
memset(&conn, 0, sizeof(conn));
socklen_t conn_len = sizeof(conn);
printf("worker: accepting admin connection\n");
conn_fd = accept(admin_fd, (struct sockaddr *)&conn, &conn_len);
if (conn_fd == -1) {
perror("worker: failed to accept admin connection");
return -1;
}
// Set accepted connection to non-blocking.
int flags = fcntl(conn_fd, F_GETFL, 0);
if (fcntl(conn_fd, F_SETFL, flags | O_NONBLOCK) == -1) {
perror("worker: failed to set non-blocking flag on worker connection");
return -1;
}
// Register connection with epoll instance.
printf("worker: adding connection to epoll\n");
struct epoll_event eadd;
memset(&eadd, 0, sizeof(eadd));
eadd.events = EPOLLIN|EPOLLRDHUP|EPOLLET;
eadd.data.fd = conn_fd;
if (epoll_ctl(poll_fd, EPOLL_CTL_ADD, conn_fd, &eadd) == -1) {
perror("worker: failed to add admin fd to epoll");
return -1;
}
} else if (event.data.fd == server_fd) {
printf("worker: processing server event\n");
// Accept connection and close it immediately. We do no real
// work on the server.
struct sockaddr_in conn;
socklen_t conn_len = sizeof(conn);
printf("worker: accepting server connection\n");
int conn_fd = accept(server_fd, (struct sockaddr *)&conn, &conn_len);
if (conn_fd == -1) {
perror("worker: failed to accept server connection");
return -1;
}
// Close connection.
printf("worker: closing server connection\n");
close(conn_fd);
} else if (event.data.fd == conn_fd) {
for (;;) {
char buf[64];
memset(&buf, 0, sizeof(buf));
int nbytes = read(conn_fd, buf, sizeof(buf));
if (nbytes >= 0) {
if (strcmp(buf, MSG_GET_SOCKS) == 0) {
printf("worker: received get socks msg\n");
if (send_sockets() == -1) {
perror("worker: failed to send sockets");
exit(EXIT_FAILURE);
}
} else {
printf("worker: ignoring unsupported msg\n");
}
// Not a real error: nothing left to read.
} else if (errno == EAGAIN || errno == EWOULDBLOCK) {
printf("worker: read all data from client connection\n");
break;
} else {
perror("worker: failed to read data from client connection");
break;
}
}
// Close client connection.
printf("worker: deleting conn_fd from epoll\n");
if (epoll_ctl(poll_fd, EPOLL_CTL_DEL, conn_fd, NULL) == -1) {
perror("worker: failed to delete conn_fd from epoll");
return -1;
}
printf("worker: closing client connection\n");
if (close(conn_fd) == -1) {
perror("worker: failed to close client connection");
return -1;
}
} else {
printf("worker: processed unknown event\n");
}
}
}
}
int send_sockets() {
struct sockaddr_un addr = {
.sun_family = AF_UNIX,
.sun_path = SOCK_PATH
};
if (connect(admin_fd, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
close(admin_fd);
return -1;
}
printf("connected to admin sock\n");
struct iovec iov = {
.iov_base = ":)", // Must send at least one byte
.iov_len = 2
};
union {
char buf[CMSG_SPACE(sizeof(server_fd))];
struct cmsghdr align;
} u;
struct msghdr msg = {
.msg_iov = &iov,
.msg_iovlen = 1,
.msg_control = u.buf,
.msg_controllen = sizeof(u.buf)
};
struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
*cmsg = (struct cmsghdr){
.cmsg_level = SOL_SOCKET,
.cmsg_type = SCM_RIGHTS,
.cmsg_len = CMSG_LEN(sizeof(server_fd))
};
memcpy(CMSG_DATA(cmsg), &server_fd, sizeof(server_fd));
printf("sending listening socket on admin sock\n");
return sendmsg(admin_fd, &msg, 0);
}