// https://syzkaller.appspot.com/bug?id=cfbc74b9eb318d6d36c48419f2b0ebbc3252ef4d
// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <dirent.h>
#include <endian.h>
#include <errno.h>
#include <pthread.h>
#include <pwd.h>
#include <setjmp.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

static unsigned long long procid;

static __thread int skip_segv;
static __thread jmp_buf segv_env;

static void segv_handler(int sig, siginfo_t* info, void* ctx)
{
  uintptr_t addr = (uintptr_t)info->si_addr;
  const uintptr_t prog_start = 1 << 20;
  const uintptr_t prog_end = 100 << 20;
  if (__atomic_load_n(&skip_segv, __ATOMIC_RELAXED) &&
      (addr < prog_start || addr > prog_end)) {
    _longjmp(segv_env, 1);
  }
  exit(sig);
}

static void install_segv_handler(void)
{
  struct sigaction sa;
  memset(&sa, 0, sizeof(sa));
  sa.sa_sigaction = segv_handler;
  sa.sa_flags = SA_NODEFER | SA_SIGINFO;
  sigaction(SIGSEGV, &sa, NULL);
  sigaction(SIGBUS, &sa, NULL);
}

#define NONFAILING(...)                                                        \
  {                                                                            \
    __atomic_fetch_add(&skip_segv, 1, __ATOMIC_SEQ_CST);                       \
    if (_setjmp(segv_env) == 0) {                                              \
      __VA_ARGS__;                                                             \
    }                                                                          \
    __atomic_fetch_sub(&skip_segv, 1, __ATOMIC_SEQ_CST);                       \
  }

static void kill_and_wait(int pid, int* status)
{
  kill(pid, SIGKILL);
  while (waitpid(-1, status, 0) != pid) {
  }
}

static void sleep_ms(uint64_t ms)
{
  usleep(ms * 1000);
}

static uint64_t current_time_ms(void)
{
  struct timespec ts;
  if (clock_gettime(CLOCK_MONOTONIC, &ts))
    exit(1);
  return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000;
}

static void use_temporary_dir(void)
{
  char tmpdir_template[] = "./syzkaller.XXXXXX";
  char* tmpdir = mkdtemp(tmpdir_template);
  if (!tmpdir)
    exit(1);
  if (chmod(tmpdir, 0777))
    exit(1);
  if (chdir(tmpdir))
    exit(1);
}

static void remove_dir(const char* dir)
{
  DIR* dp;
  struct dirent* ep;
  dp = opendir(dir);
  if (dp == NULL)
    exit(1);
  while ((ep = readdir(dp))) {
    if (strcmp(ep->d_name, ".") == 0 || strcmp(ep->d_name, "..") == 0)
      continue;
    char filename[FILENAME_MAX];
    snprintf(filename, sizeof(filename), "%s/%s", dir, ep->d_name);
    struct stat st;
    if (lstat(filename, &st))
      exit(1);
    if (S_ISDIR(st.st_mode)) {
      remove_dir(filename);
      continue;
    }
    if (unlink(filename))
      exit(1);
  }
  closedir(dp);
  if (rmdir(dir))
    exit(1);
}

static void thread_start(void* (*fn)(void*), void* arg)
{
  pthread_t th;
  pthread_attr_t attr;
  pthread_attr_init(&attr);
  pthread_attr_setstacksize(&attr, 128 << 10);
  int i;
  for (i = 0; i < 100; i++) {
    if (pthread_create(&th, &attr, fn, arg) == 0) {
      pthread_attr_destroy(&attr);
      return;
    }
    if (errno == EAGAIN) {
      usleep(50);
      continue;
    }
    break;
  }
  exit(1);
}

typedef struct {
  pthread_mutex_t mu;
  pthread_cond_t cv;
  int state;
} event_t;

static void event_init(event_t* ev)
{
  if (pthread_mutex_init(&ev->mu, 0))
    exit(1);
  if (pthread_cond_init(&ev->cv, 0))
    exit(1);
  ev->state = 0;
}

static void event_reset(event_t* ev)
{
  ev->state = 0;
}

static void event_set(event_t* ev)
{
  pthread_mutex_lock(&ev->mu);
  if (ev->state)
    exit(1);
  ev->state = 1;
  pthread_mutex_unlock(&ev->mu);
  pthread_cond_broadcast(&ev->cv);
}

static void event_wait(event_t* ev)
{
  pthread_mutex_lock(&ev->mu);
  while (!ev->state)
    pthread_cond_wait(&ev->cv, &ev->mu);
  pthread_mutex_unlock(&ev->mu);
}

static int event_isset(event_t* ev)
{
  pthread_mutex_lock(&ev->mu);
  int res = ev->state;
  pthread_mutex_unlock(&ev->mu);
  return res;
}

static int event_timedwait(event_t* ev, uint64_t timeout)
{
  uint64_t start = current_time_ms();
  uint64_t now = start;
  pthread_mutex_lock(&ev->mu);
  for (;;) {
    if (ev->state)
      break;
    uint64_t remain = timeout - (now - start);
    struct timespec ts;
    ts.tv_sec = remain / 1000;
    ts.tv_nsec = (remain % 1000) * 1000 * 1000;
    pthread_cond_timedwait(&ev->cv, &ev->mu, &ts);
    now = current_time_ms();
    if (now - start > timeout)
      break;
  }
  int res = ev->state;
  pthread_mutex_unlock(&ev->mu);
  return res;
}

static void sandbox_common()
{
  if (setsid() == -1)
    exit(1);
  struct rlimit rlim;
  rlim.rlim_cur = rlim.rlim_max = 8 << 20;
  setrlimit(RLIMIT_MEMLOCK, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 1 << 20;
  setrlimit(RLIMIT_FSIZE, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 1 << 20;
  setrlimit(RLIMIT_STACK, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 0;
  setrlimit(RLIMIT_CORE, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 256;
  setrlimit(RLIMIT_NOFILE, &rlim);
}

static void loop();

static int do_sandbox_none(void)
{
  sandbox_common();
  loop();
  return 0;
}

struct thread_t {
  int created, call;
  event_t ready, done;
};

static struct thread_t threads[16];
static void execute_call(int call);
static int running;

static void* thr(void* arg)
{
  struct thread_t* th = (struct thread_t*)arg;
  for (;;) {
    event_wait(&th->ready);
    event_reset(&th->ready);
    execute_call(th->call);
    __atomic_fetch_sub(&running, 1, __ATOMIC_RELAXED);
    event_set(&th->done);
  }
  return 0;
}

static void execute_one(void)
{
  int i, call, thread;
  int collide = 0;
again:
  for (call = 0; call < 11; call++) {
    for (thread = 0; thread < (int)(sizeof(threads) / sizeof(threads[0]));
         thread++) {
      struct thread_t* th = &threads[thread];
      if (!th->created) {
        th->created = 1;
        event_init(&th->ready);
        event_init(&th->done);
        event_set(&th->done);
        thread_start(thr, th);
      }
      if (!event_isset(&th->done))
        continue;
      event_reset(&th->done);
      th->call = call;
      __atomic_fetch_add(&running, 1, __ATOMIC_RELAXED);
      event_set(&th->ready);
      if (collide && (call % 2) == 0)
        break;
      event_timedwait(&th->done, 45);
      break;
    }
  }
  for (i = 0; i < 100 && __atomic_load_n(&running, __ATOMIC_RELAXED); i++)
    sleep_ms(1);
  if (!collide) {
    collide = 1;
    goto again;
  }
}

static void execute_one(void);

#define WAIT_FLAGS 0

static void loop(void)
{
  int iter;
  for (iter = 0;; iter++) {
    char cwdbuf[32];
    sprintf(cwdbuf, "./%d", iter);
    if (mkdir(cwdbuf, 0777))
      exit(1);
    int pid = fork();
    if (pid < 0)
      exit(1);
    if (pid == 0) {
      if (chdir(cwdbuf))
        exit(1);
      execute_one();
      exit(0);
    }
    int status = 0;
    uint64_t start = current_time_ms();
    for (;;) {
      if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid)
        break;
      sleep_ms(1);
      if (current_time_ms() - start < 5 * 1000)
        continue;
      kill_and_wait(pid, &status);
      break;
    }
    remove_dir(cwdbuf);
  }
}

#ifndef SYS_fork
#define SYS_fork 2
#endif
#ifndef SYS_mmap
#define SYS_mmap 197
#endif
#ifndef SYS_setegid
#define SYS_setegid 182
#endif
#ifndef SYS_setpgid
#define SYS_setpgid 82
#endif
#ifndef SYS_stat
#define SYS_stat 439
#endif
#ifndef SYS_utimes
#define SYS_utimes 420
#endif

uint64_t r[3] = {0x0, 0x0, 0x0};

void execute_call(int call)
{
  intptr_t res;
  switch (call) {
  case 0:
    NONFAILING(memcpy((void*)0x20000040, "./file0\000", 8));
    res = syscall(SYS_stat, 0x20000040ul, 0x20000080ul);
    if (res != -1)
      NONFAILING(r[0] = *(uint32_t*)0x200000a0);
    break;
  case 1:
    syscall(SYS_setegid, r[0]);
    break;
  case 2:
    syscall(SYS_setpgid, 0, 0);
    break;
  case 3:
    res = syscall(SYS_fork);
    if (res != -1)
      r[1] = res;
    break;
  case 4:
    syscall(SYS_setpgid, r[1], 0);
    break;
  case 5:
    syscall(SYS_setpgid, 0, r[1]);
    break;
  case 6:
    NONFAILING(*(uint64_t*)0x20000200 = 0x7fff);
    NONFAILING(*(uint64_t*)0x20000208 = 0x6df);
    NONFAILING(*(uint64_t*)0x20000210 = 0xa2e);
    NONFAILING(*(uint64_t*)0x20000218 = 0x80);
    syscall(SYS_utimes, 0ul, 0x20000200ul);
    break;
  case 7:
    syscall(SYS_setpgid, r[1], 0);
    break;
  case 8:
    res = syscall(SYS_fork);
    if (res != -1)
      r[2] = res;
    break;
  case 9:
    syscall(SYS_setpgid, r[2], 0);
    break;
  case 10:
    syscall(SYS_setpgid, 0, 0);
    break;
  }
}
int main(void)
{
  syscall(SYS_mmap, 0x20000000ul, 0x1000000ul, 3ul, 0x1012ul, -1, 0ul, 0ul);
  install_segv_handler();
  for (procid = 0; procid < 6; procid++) {
    if (fork() == 0) {
      use_temporary_dir();
      do_sandbox_none();
    }
  }
  sleep(1000000);
  return 0;
}