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main_loop.c
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main_loop.c
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#include <event2/event.h>
#include <event2/dns.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <getopt.h>
#include <memory.h>
#include <limits.h>
#include <assert.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <signal.h>
#include "transfer.h"
#include "handle_client.h"
#include "common.h"
#include "stack.h"
void printf_and_exit(const char *format, ...) {
va_list arglist;
va_start(arglist, format);
vfprintf(stderr, format, arglist);
va_end(arglist);
fprintf(stderr, "\n");
exit(EXIT_FAILURE);
}
void perror_and_exit(const char *s) {
perror(s);
exit(EXIT_FAILURE);
}
void everror_and_exit(const char *s) {
perror_and_exit(s);
}
typedef struct {
struct sockaddr_storage addr;
socklen_t addr_len;
} server_bind_addr_struct;
typedef struct {
server_bind_addr_struct server_bind_addr;
size_t transfer_buffer_size;
} global_config_struct;
typedef struct {
int server_sockfd;
client_handler_common_struct bases;
struct event *int_signal_event;
struct event *server_event;
} global_resources_struct;
#define INTERRUPT_SIGNAL SIGINT
void signal_cb(evutil_socket_t signum, short ev_flag, void *arg) {
struct event_base *base = (struct event_base *)arg;
assert(ev_flag == EV_SIGNAL);
(void)ev_flag;
switch(signum) {
case INTERRUPT_SIGNAL: {
if (event_base_loopbreak(base)) {everror("event_base_loopbreak"); return;}
break;
}
default:
assert(0);
}
}
void server_accept_cb(evutil_socket_t server_sockfd, short ev_flag, void *arg) {
client_handler_common_struct *bases = (client_handler_common_struct *)arg;
assert(ev_flag == EV_READ);
(void)ev_flag;
int client_sockfd = accept(server_sockfd, NULL, NULL);
if (client_sockfd < 0) {perror("accept"); return;}
if (make_socket_nonblocking(client_sockfd)) {
perror("fcntl");
if (close(client_sockfd)) perror("close");
return;
}
client_handler_construct_and_run(bases, client_sockfd);
}
void setup_server_socket(global_config_struct *global_config, global_resources_struct *global_resources) {
server_bind_addr_struct *server_bind_addr = &global_config->server_bind_addr;
struct sockaddr_storage *addr = &server_bind_addr->addr;
socklen_t addr_len = server_bind_addr->addr_len;
int server_sockfd = socket(addr->ss_family, SOCK_STREAM, 0);
if (server_sockfd < 0) perror_and_exit("socket");
int yes = 1;
if (setsockopt(server_sockfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes))) perror_and_exit("setsockopt");
if (bind(server_sockfd, (struct sockaddr *)addr, addr_len)) perror_and_exit("bind");
global_resources->server_sockfd = server_sockfd;
}
#define MAXPENDING 5
void listen_server_socket(global_resources_struct *global_resources) {
if (listen(global_resources->server_sockfd, MAXPENDING)) perror_and_exit("listen");
}
void setup_events(global_resources_struct *global_resources) {
struct event_base *base = event_base_new();
if (base == NULL) everror_and_exit("event_base_new");
global_resources->bases.base = base;
struct evdns_base *dns_base = evdns_base_new(base, EVDNS_BASE_INITIALIZE_NAMESERVERS);
if (dns_base == NULL) everror_and_exit("evdns_base_new");
if (evdns_base_set_option(dns_base, "randomize-case", "0")) everror_and_exit("evdns_base_set_option");
global_resources->bases.dns_base = dns_base;
struct event *int_signal_event = evsignal_new(base, INTERRUPT_SIGNAL, signal_cb, global_resources->bases.base);
if (int_signal_event == NULL) everror_and_exit("evsignal_new");
global_resources->int_signal_event = int_signal_event;
if (event_add(int_signal_event, NULL)) everror_and_exit("event_add");
struct event *server_event = event_new(base, global_resources->server_sockfd, EV_READ|EV_PERSIST,
server_accept_cb, &global_resources->bases);
if (server_event == NULL) everror_and_exit("event_new");
global_resources->server_event = server_event;
if (event_add(server_event, NULL)) everror_and_exit("event_add");
}
void dispatch(global_resources_struct *global_resources) {
if (event_base_dispatch(global_resources->bases.base)) everror_and_exit("event_base_dispatch");
}
typedef bool (*events_filter_type)(const struct event *event);
typedef void (*event_cb_arg_destruct_type)(struct event *event);
typedef struct {
stack_struct events_stack;
events_filter_type events_filter;
} enum_clients_events_cb_arg_struct;
int enum_clients_events_cb(const struct event_base *base, const struct event *event, void *arg) {
(void)base;
enum_clients_events_cb_arg_struct *cb_arg = (enum_clients_events_cb_arg_struct *)arg;
if (cb_arg->events_filter(event)) stack_push(&cb_arg->events_stack, event);
return 0;
}
void free_all_clients_events(struct event_base *base, events_filter_type filter, event_cb_arg_destruct_type destruct) {
enum_clients_events_cb_arg_struct arg;
stack_new(&arg.events_stack);
arg.events_filter = filter;
while (event_base_foreach_event(base, enum_clients_events_cb, &arg) > 0);
while (!stack_is_empty(&arg.events_stack)) {
struct event *event = stack_pop(&arg.events_stack);
assert(event != NULL);
if (event_del(event)) everror("event_del");
destruct(event);
event_free(event);
}
}
void close_all(global_resources_struct *global_resources) {
if (event_del(global_resources->int_signal_event)) everror("event_del");
event_free(global_resources->int_signal_event);
if (event_del(global_resources->server_event)) everror("event_del");
event_free(global_resources->server_event);
free_all_clients_events(global_resources->bases.base, client_handler_events_filter, client_handler_destruct);
free_all_clients_events(global_resources->bases.base, transfer_events_filter, transfer_destruct);
evdns_base_free(global_resources->bases.dns_base, 0);
event_base_free(global_resources->bases.base);
if (close(global_resources->server_sockfd)) perror("close");
}
void run(global_config_struct *global_config) {
global_resources_struct global_resources;
setup_server_socket(global_config, &global_resources);
global_resources.bases.transfer_buffer_size = global_config->transfer_buffer_size;
setup_events(&global_resources);
listen_server_socket(&global_resources);
dispatch(&global_resources);
close_all(&global_resources);
}
#define default_transfer_buffer_size (64*1024)
#define default_bind_port 1080
#define default_bind_addr INADDR_LOOPBACK
#if default_transfer_buffer_size > SSIZE_MAX
# error
#endif
#define LARGE_PORT_NUMBER 65536
#if default_bind_port <=0 || default_bind_port >= LARGE_PORT_NUMBER
# error
#endif
void print_help(const char *prog_name) {
printf(
"Usage: %s [-hps] [--bind-ip <ip>|-bind-ipv6 <ipv6>]\n"
" -h, --help display this help and exit\n"
" --bind-ip <ip> bind to IP address <ip> (default: 127.0.0.1)\n"
" --bind-ipv6 <ipv6> bind to IPv6 address <ipv6>\n"
" -p, --port <port> bind to <port> (default: %u)\n"
" -s, --size <size> assing two transfer buffers of <size> bytes\n"
" for every client (default: 64K)\n",
#if default_transfer_buffer_size != 64*1024
# warning
#endif
prog_name, default_bind_port
);
}
typedef struct {
char *bind_ipv4;
char *bind_ipv6;
char *bind_port;
char *transfer_buffer_size;
} cmdline_args_struct;
void parse_args(int argc, char* argv[], cmdline_args_struct *args) {
args->bind_ipv4 = NULL;
args->bind_ipv6 = NULL;
args->bind_port = NULL;
args->transfer_buffer_size = NULL;
static const char optstring[] = "hp:s:";
static const struct option longopts[] = {
{"help", no_argument, 0, 'h'},
{"bind-ip", required_argument, 0, '4'},
{"bind-ipv6", required_argument, 0, '6'},
{"port", required_argument, 0, 'p'},
{"size", required_argument, 0, 's'},
{0, 0, 0, 0}
};
int longindex = 0;
int c;
while (1) {
c = getopt_long (argc, argv, optstring, longopts, &longindex);
if (c == -1) break;
switch (c) {
case 'h':
print_help(argv[0]);
exit(EXIT_SUCCESS);
break;
case '4':
args->bind_ipv4 = optarg;
break;
case '6':
args->bind_ipv6 = optarg;
break;
case 'p':
args->bind_port = optarg;
break;
case 's':
args->transfer_buffer_size = optarg;
break;
default:
goto print_help_and_exit_err;
}
}
if (optind < argc) goto print_help_and_exit_err;
if (args->bind_ipv4 != NULL && args->bind_ipv6 != NULL) goto print_help_and_exit_err;
return;
print_help_and_exit_err:
print_help(argv[0]);
exit(EXIT_FAILURE);
}
void process_args(int argc, char* argv[], global_config_struct *global_config) {
cmdline_args_struct args_;
cmdline_args_struct *args = &args_;
parse_args(argc, argv, args);
in_port_t port;
{
if (args->bind_port != NULL) {
int p = atoi(args->bind_port);
if (p <= 0 || p >= LARGE_PORT_NUMBER)
printf_and_exit("invalid port");
else
port = (in_port_t)p;
} else {
port = default_bind_port;
}
}
{
server_bind_addr_struct *server_bind_addr = &global_config->server_bind_addr;
assert(args->bind_ipv4 == NULL || args->bind_ipv6 == NULL);
if (args->bind_ipv6 != NULL) {
assert(sizeof(server_bind_addr->addr) >= sizeof(struct sockaddr_in6));
struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&server_bind_addr->addr;
memset(sin6, 0, sizeof(struct sockaddr_in6));
sin6->sin6_family = AF_INET6;
sin6->sin6_port = htons(port);
int ret = inet_pton(AF_INET6, args->bind_ipv6, &sin6->sin6_addr);
if (ret < 0) perror_and_exit("inet_pton");
else if (ret != 1) printf_and_exit("invalid ipv6 address");
server_bind_addr->addr_len = sizeof(struct sockaddr_in6);
} else {
assert(sizeof(server_bind_addr->addr) >= sizeof(struct sockaddr_in));
struct sockaddr_in *sin = (struct sockaddr_in *)&server_bind_addr->addr;
sin->sin_family = AF_INET;
sin->sin_port = htons(port);
if (args->bind_ipv4 == NULL) {
sin->sin_addr.s_addr = htonl(default_bind_addr);
} else {
if (!inet_aton(args->bind_ipv4, &sin->sin_addr)) printf_and_exit("invalid ip address");
}
server_bind_addr->addr_len = sizeof(struct sockaddr_in);
}
}
size_t transfer_buffer_size;
{
if (args->transfer_buffer_size != NULL) {
long long int size = atoll(args->transfer_buffer_size);
if (size <= 0)
printf_and_exit("invalid transfer buffer size");
else if (size == LONG_MAX || size > SSIZE_MAX)
printf_and_exit("too large transfer buffer size");
else
transfer_buffer_size = (size_t)size;
} else {
transfer_buffer_size = default_transfer_buffer_size;
}
}
global_config->transfer_buffer_size = transfer_buffer_size;
}
int main(int argc, char* argv[]) {
global_config_struct global_config;
process_args(argc, argv, &global_config);
run(&global_config);
#ifndef NDEBUG
printf_err("DONE");
#endif
return 0;
}