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#include <libssh/callbacks.h>
#include <libssh/server.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/wait.h>
#include "../config.h"
#include "session.h"
/* 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;
static ssh_session session;
__attribute__((noreturn)) void sigint_handler(int signo)
{
(void) signo;
ssh_free(session);
ssh_bind_free(sshbind);
ssh_finalize();
exit(0);
}
int main()
{
// Set up SIGCHLD handler
struct sigaction sa;
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 1;
}
// 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;
}
// Initializing ssh context
ssh_init();
// Initializing ssh_bind
sshbind = ssh_bind_new();
if (sshbind == NULL) {
fprintf(stderr, "Error initializing ssh_bind\n");
exit(-1);
}
int port = 2222;
ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_BINDPORT, &port);
ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_DSAKEY, DSAKEY_PATH);
ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_RSAKEY, RSAKEY_PATH);
ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_ECDSAKEY, ECDSAKEY_PATH);
if (ssh_bind_listen(sshbind) < 0) {
printf("Error listening to socket: %s\n", ssh_get_error(sshbind));
ssh_bind_free(sshbind);
ssh_finalize();
return 1;
}
while (1) {
session = ssh_new();
if (session == NULL) {
fprintf(stderr, "Error initializing ssh_session\n");
break;
}
int verbosity = SSH_LOG_PROTOCOL;
ssh_options_set(session, SSH_OPTIONS_LOG_VERBOSITY, &verbosity);
// Blocks until there is a new incoming connection
if (ssh_bind_accept(sshbind,session) == SSH_OK){
switch(fork()) {
case 0:
/* 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);
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);
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);
ssh_finalize();
return 1;
}
/* 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);
ssh_finalize();
return 0;
}
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