// https://syzkaller.appspot.com/bug?id=6f7ce2a0536580a94f65f44e478732ec505e88af
// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <dirent.h>
#include <endian.h>
#include <pwd.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 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 = opendir(dir);
  if (dp == NULL)
    exit(1);
  struct dirent* ep = 0;
  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);
}

#define __syscall syscall

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 wait_for_loop(int pid)
{
  if (pid < 0)
    exit(1);
  int status = 0;
  while (waitpid(-1, &status, WUNTRACED) != pid) {
  }
  return WEXITSTATUS(status);
}

static int do_sandbox_setuid(void)
{
  int pid = fork();
  if (pid != 0)
    return wait_for_loop(pid);
  sandbox_common();
  char pwbuf[1024];
  struct passwd *pw, pwres;
  if (getpwnam_r("nobody", &pwres, pwbuf, sizeof(pwbuf), &pw) != 0 || !pw)
    exit(1);
  if (setgroups(0, NULL))
    exit(1);
  if (setgid(pw->pw_gid))
    exit(1);
  if (setuid(pw->pw_uid))
    exit(1);
  loop();
  exit(1);
}

static void execute_one(void);

#define WAIT_FLAGS 0

static void loop(void)
{
  int iter = 0;
  for (;; 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);
  }
}

void execute_one(void)
{
  memcpy((void*)0x20000340, "./file0\000", 8);
  syscall(SYS_mkdir, 0x20000340ul, 0ul);
  syscall(SYS_sendmsg, -1, 0ul, 0ul);
}
int main(void)
{
  syscall(SYS_mmap, 0x20000000ul, 0x1000000ul, 3ul, 0x1012ul, -1, 0ul, 0ul);
  for (procid = 0; procid < 2; procid++) {
    if (fork() == 0) {
      use_temporary_dir();
      do_sandbox_setuid();
    }
  }
  sleep(1000000);
  return 0;
}