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#include <libssh/callbacks.h>
#include <libssh/server.h>
#include <parg.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/wait.h>
#include "common/config.h"
#include "session.h"
#include "state.h"
static void usage(char **argv)
{
printf("Usage: %s [-h] [-v] [-t] [-f] [-c STRING]\n", argv[0]);
printf(" -h : show this help message and exit\n");
printf(" -v : show version and exit\n");
printf(" -t : test configuration file and exit\n");
printf(" -f : stay in foreground (don't fork)\n");
printf(" -c : specify a path to a configuration file to use instead of the default %s\n", CONFIG_PATH);
}
/* SIGCHLD handler for cleaning up dead children. */
static void sigchld_handler(int signo) {
(void) signo;
while (waitpid(-1, NULL, WNOHANG) > 0);
}
/* SIGINT handler for cleaning up on forced exit. */
static ssh_bind sshbind = NULL;
static ssh_session session = NULL;
__attribute__((noreturn)) static void sigint_handler(int signo)
{
(void) signo;
ssh_disconnect(session);
ssh_free(session);
ssh_bind_free(sshbind);
state_clean();
config_clean();
ssh_finalize();
exit(0);
}
int main(int argc, char **argv)
{
// Set up SIGINT handler
struct sigaction sa2;
sa2.sa_handler = sigint_handler;
sigemptyset(&sa2.sa_mask);
sa2.sa_flags = 0;
if (sigaction(SIGINT, &sa2, NULL) != 0) {
fprintf(stderr, "Failed to register SIGINT handler\n");
return 1;
}
// Argument parsing
struct parg_state ps;
int c;
char test_only = 0, dont_fork = 0;
const char *config_file = CONFIG_PATH;
parg_init(&ps);
//while ((int c = parg_getopt(&ps, argc, argv, "hs:v")) != -1) {
while ((c = parg_getopt(&ps, argc, argv, "hvtfc:")) != -1) {
switch (c) {
case 1:
printf("invalid non option '%s'\n", ps.optarg);
return 2;
case 'h':
usage(argv);
return 0;
case 'v':
printf("%s %s - %s\n", argv[0], VERSION, GIT_HASH);
return 0;
case 't':
test_only = 1;
break;
case 'f':
dont_fork = 1;
break;
case 'c':
config_file = ps.optarg;
break;
case '?':
if (ps.optopt == 'c') {
printf("option -c requires the path to a configuration in argument.\n");
}
else {
printf("unknown option -%c\n", ps.optopt);
}
usage(argv);
return 3;
default:
printf("error: unhandled option -%c\n", c);
return 4;
break;
}
}
if (test_only) {
if (config_load(config_file) != 0) {
fprintf(stderr, "Failed to load configuration file %s.\n", CONFIG_PATH);
config_clean();
return 5;
}
config_clean();
return 0;
}
struct sigaction sa;
if (!dont_fork) {
// Set up SIGCHLD handler
sa.sa_handler = sigchld_handler;
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART | SA_NOCLDSTOP;
if (sigaction(SIGCHLD, &sa, NULL) != 0) {
fprintf(stderr, "Failed to register SIGCHLD handler\n");
return 6;
}
}
// Initializing ssh context
if (ssh_init() != 0) {
fprintf(stderr, "Failed to initialize libssh global cryptographic data structures.\n");
return 7;
};
// Initializing configuration context
if (config_load(config_file) != 0) {
fprintf(stderr, "Failed to load configuration file %s.\n", CONFIG_PATH);
config_clean();
ssh_finalize();
return 8;
}
// Initializing ssh_bind
sshbind = ssh_bind_new();
if (sshbind == NULL) {
fprintf(stderr, "Error initializing ssh_bind\n");
config_clean();
ssh_finalize();
return 9;
}
int listen_port = config_get_port();
ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_BINDPORT, &listen_port);
ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_DSAKEY, config_get_key_dsa());
ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_RSAKEY, config_get_key_rsa());
ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_ECDSAKEY, config_get_key_ecdsa());
if (ssh_bind_listen(sshbind) < 0) {
printf("Error listening to socket: %s\n", ssh_get_error(sshbind));
ssh_bind_free(sshbind);
config_clean();
ssh_finalize();
return 10;
}
while (1) {
session = ssh_new();
if (session == NULL) {
fprintf(stderr, "Error initializing ssh_session\n");
break;
}
#ifdef LIBSSH_VERBOSE_OUTPUT
int verbosity = SSH_LOG_PROTOCOL;
ssh_options_set(session, SSH_OPTIONS_LOG_VERBOSITY, &verbosity);
#endif
// Blocks until there is a new incoming connection
if (ssh_bind_accept(sshbind,session) == SSH_OK){
int res = 0;
if (!dont_fork) {
res = fork();
}
switch(res) {
case 0:
if (!dont_fork) {
/* Remove the SIGCHLD handler inherited from parent. */
sa.sa_handler = SIG_DFL;
sigaction(SIGCHLD, &sa, NULL);
}
/* Remove socket binding, which allows us to restart the parent process, without terminating existing sessions. */
ssh_bind_free(sshbind);
sshbind = NULL;
ssh_event event = ssh_event_new();
if (event != NULL) {
/* Blocks until the SSH session ends */
handle_session(event, session);
ssh_event_free(event);
} else {
fprintf(stderr, "Could not create polling context\n");
}
ssh_disconnect(session);
ssh_free(session);
config_clean();
ssh_finalize();
return 0;
case -1:
fprintf(stderr, "Failed to fork\n");
}
} else {
fprintf(stderr, "Error accepting a connection : %s\n", ssh_get_error(sshbind));
ssh_disconnect(session);
ssh_free(session);
ssh_bind_free(sshbind);
config_clean();
ssh_finalize();
return 10;
}
/* Since the session has been passed to a child fork, do some cleaning up at the parent process. */
ssh_disconnect(session);
ssh_free(session);
}
ssh_bind_free(sshbind);
config_clean();
ssh_finalize();
return 0;
}
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