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#include <cstddef>
#include <pthread.h>
#include <signal.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <cstdlib>
#include <ctime>
#include <climits>
#include <vector>
#include <cstring>
#include "logging_test.h"
Faulty_Logger faulty_logger;
NXLog good_logger;
void print_sigmask () {
sigset_t orig_mask;
sigemptyset (&orig_mask);
pthread_sigmask (SIG_SETMASK, NULL, &orig_mask);
bool empty = true;
for (std::size_t i = 0; i < NSIG; ++i) {
if (sigismember (&orig_mask, i)) {
nxdbg_good << "Signal i (" << i << ") in signal mask." << std::endl;
empty = false;
}
}
if (empty) {
nxdbg_good << "Signal mask empty.";
}
}
void* log_task (void* /* unused */) {
/* print_sigmask (); */
for (std::size_t i = 0; i < 10; ++i) {
nxinfo << "Log message " << i << std::endl;
}
}
void sig_handler (int signo) {
nxinfo << "Received signal " << signo << std::endl;
}
void setup_faulty_logger () {
faulty_logger.log_level (true);
faulty_logger.log_unix_time (false);
faulty_logger.log_time (true);
faulty_logger.log_location (true);
faulty_logger.log_thread_id (true);
faulty_logger.level (NXDEBUG);
}
void setup_good_logger () {
good_logger.log_level (true);
good_logger.log_unix_time (false);
good_logger.log_time (true);
good_logger.log_location (true);
good_logger.log_thread_id (true);
good_logger.level (NXDEBUG);
}
pthread_t spawn_thread () {
pthread_t thread_id;
int pthread_ret;
sigset_t block_mask, orig_mask;
sigemptyset (&orig_mask);
sigfillset (&block_mask);
pthread_sigmask (SIG_BLOCK, &block_mask, &orig_mask);
pthread_ret = pthread_create (&thread_id, NULL, log_task, NULL);
pthread_sigmask (SIG_SETMASK, &orig_mask, NULL);
return (thread_id);
}
void install_signal_handler () {
struct sigaction sa;
sa.sa_handler = sig_handler;
sigemptyset (&sa.sa_mask);
sa.sa_flags = SA_RESTART;
if (-1 == sigaction (SIGUSR1, &sa, NULL)) {
nxerr_good << "Unable to install signal handler!" << std::endl;
}
else {
nxdbg_good << "Signal handler registered successfully for SIGUSR1." << std::endl;
}
}
void killing_process_work (pid_t parent_pid) {
/* Seed PRNG. */
std::srand (std::time (0));
for (std::size_t i = 0; i < 25; ++i) {
/* Sleep for 4 seconds + some random number up to a second. */
std::size_t rand_add = (std::rand () % 1000000);
usleep (4000000 + rand_add);
/* Send SIGUSR1 to parent process. */
nxdbg_good << "Sending SIGUSR1 (" << SIGUSR1 << ") to parent_pid (" << parent_pid << ")" << std::endl;
if (kill (parent_pid, SIGUSR1)) {
int saved_errno = errno;
nxerr_good << "Failed to deliver signal to parent, aborting." << std::endl;
nxerr_good << "Error " << saved_errno << ": " << strerror (saved_errno) << std::endl;
exit (EXIT_FAILURE);
}
}
exit (EXIT_SUCCESS);
}
void killing_process_init (int argc, char **argv) {
/* We're in the "killing process". */
pid_t parent_pid = getppid ();
setup_good_logger ();
for (std::size_t i = 0; i < argc; ++i) {
nxdbg_good << "argv[" << i << "]: " << argv[i] << std::endl;
}
char *end = NULL;
errno = 0;
long parent_pid_check = std::strtol (argv[1], &end, 0);
if ((errno == ERANGE) && (parent_pid_check == LONG_MAX)) {
/* Overflow, handle gracefully. */
parent_pid_check = 1;
}
if ((errno == ERANGE) && (parent_pid_check == LONG_MIN)) {
/* Underflow, handle gracefully. */
parent_pid_check = 1;
}
if (*end) {
/* Conversion error (for inputs like "<number>X", end will point to X.) */
parent_pid_check = 1;
}
if (parent_pid != parent_pid_check) {
nxinfo_good << "Parent PID verification via first argument failed, trusting getppid ()." << std::endl;
}
killing_process_work (parent_pid);
}
int main (int argc, char **argv) {
if (argc > 1) {
killing_process_init (argc, argv);
}
else {
/* That's the main process. */
/* First, fork and create the "killing process". */
pid_t pid = fork ();
if (0 == pid) {
/* Child process. */
pid_t parent_pid = getppid ();
/* Prepare to pass-through parent PID. */
std::stringstream ss;
ss << parent_pid;
std::vector<std::string> new_argv;
new_argv.push_back (std::string (argv[0]));
new_argv.push_back (ss.str ());
std::vector<char *> new_argv_c_str;
for (std::vector<std::string>::iterator it = new_argv.begin (); it != new_argv.end (); ++it) {
const char *elem = (*it).c_str ();
new_argv_c_str.push_back (strndup (elem, std::strlen (elem)));
}
/* Add null pointer as last element. */
new_argv_c_str.push_back (0);
/* Relaunch, with argv[1] containing the ppid. */
if (0 != execvp (new_argv_c_str.front (), &(new_argv_c_str.front ()))) {
const int saved_errno = errno;
std::cerr << "Failed to start \"killing process\"! Panic!" << std::endl;
std::cerr << "System error: " << std::strerror (saved_errno) << std::endl;
exit (EXIT_FAILURE);
}
}
else if (0 > pid) {
const int saved_errno = errno;
std::cerr << "Error while forking main process! Panic!" << std::endl;
std::cerr << "System error: " << std::strerror (saved_errno) << std::endl;
exit (EXIT_FAILURE);
}
else {
/* Main process. */
/* Falls through to general code below. */
}
}
setup_faulty_logger ();
pthread_t thread_id = spawn_thread ();
setup_good_logger ();
install_signal_handler ();
/* print_sigmask (); */
log_task (NULL);
pthread_join (thread_id, NULL);
exit (EXIT_SUCCESS);
}
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