// https://syzkaller.appspot.com/bug?id=feee6b911a79139455754b0be0495adb996a07fa
// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE

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

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 bool write_file(const char* file, const char* what, ...)
{
  char buf[1024];
  va_list args;
  va_start(args, what);
  vsnprintf(buf, sizeof(buf), what, args);
  va_end(args);
  buf[sizeof(buf) - 1] = 0;
  int len = strlen(buf);
  int fd = open(file, O_WRONLY | O_CLOEXEC);
  if (fd == -1)
    return false;
  if (write(fd, buf, len) != len) {
    int err = errno;
    close(fd);
    errno = err;
    return false;
  }
  close(fd);
  return true;
}

static int inject_fault(int nth)
{
  int fd;
  fd = open("/proc/thread-self/fail-nth", O_RDWR);
  if (fd == -1)
    exit(1);
  char buf[16];
  sprintf(buf, "%d", nth);
  if (write(fd, buf, strlen(buf)) != (ssize_t)strlen(buf))
    exit(1);
  return fd;
}

static void kill_and_wait(int pid, int* status)
{
  kill(-pid, SIGKILL);
  kill(pid, SIGKILL);
  for (int i = 0; i < 100; i++) {
    if (waitpid(-1, status, WNOHANG | __WALL) == pid)
      return;
    usleep(1000);
  }
  DIR* dir = opendir("/sys/fs/fuse/connections");
  if (dir) {
    for (;;) {
      struct dirent* ent = readdir(dir);
      if (!ent)
        break;
      if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0)
        continue;
      char abort[300];
      snprintf(abort, sizeof(abort), "/sys/fs/fuse/connections/%s/abort",
               ent->d_name);
      int fd = open(abort, O_WRONLY);
      if (fd == -1) {
        continue;
      }
      if (write(fd, abort, 1) < 0) {
      }
      close(fd);
    }
    closedir(dir);
  } else {
  }
  while (waitpid(-1, status, __WALL) != pid) {
  }
}

static void setup_test()
{
  prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
  setpgrp();
  write_file("/proc/self/oom_score_adj", "1000");
}

static const char* setup_fault()
{
  int fd = open("/proc/self/make-it-fail", O_WRONLY);
  if (fd == -1)
    return "CONFIG_FAULT_INJECTION is not enabled";
  close(fd);
  fd = open("/proc/thread-self/fail-nth", O_WRONLY);
  if (fd == -1)
    return "kernel does not have systematic fault injection support";
  close(fd);
  static struct {
    const char* file;
    const char* val;
    bool fatal;
  } files[] = {
      {"/sys/kernel/debug/failslab/ignore-gfp-wait", "N", true},
      {"/sys/kernel/debug/fail_futex/ignore-private", "N", false},
      {"/sys/kernel/debug/fail_page_alloc/ignore-gfp-highmem", "N", false},
      {"/sys/kernel/debug/fail_page_alloc/ignore-gfp-wait", "N", false},
      {"/sys/kernel/debug/fail_page_alloc/min-order", "0", false},
  };
  unsigned i;
  for (i = 0; i < sizeof(files) / sizeof(files[0]); i++) {
    if (!write_file(files[i].file, files[i].val)) {
      if (files[i].fatal)
        return "failed to write fault injection file";
    }
  }
  return NULL;
}

static void execute_one(void);

#define WAIT_FLAGS __WALL

static void loop(void)
{
  int iter = 0;
  for (;; iter++) {
    int pid = fork();
    if (pid < 0)
      exit(1);
    if (pid == 0) {
      setup_test();
      execute_one();
      exit(0);
    }
    int status = 0;
    uint64_t start = current_time_ms();
    for (;;) {
      sleep_ms(10);
      if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid)
        break;
      if (current_time_ms() - start < 5000)
        continue;
      kill_and_wait(pid, &status);
      break;
    }
  }
}

uint64_t r[2] = {0xffffffffffffffff, 0xffffffffffffffff};

void execute_one(void)
{
  intptr_t res = 0;
  if (write(1, "executing program\n", sizeof("executing program\n") - 1)) {
  }
  memcpy((void*)0x20002040, "./file0\000", 8);
  syscall(__NR_mkdirat, /*fd=*/0xffffff9c, /*path=*/0x20002040ul, /*mode=*/0ul);
  memcpy((void*)0x20000340, "./file1\000", 8);
  syscall(__NR_mkdirat, /*fd=*/0xffffff9c, /*path=*/0x20000340ul, /*mode=*/0ul);
  memcpy((void*)0x20000300, "./bus\000", 6);
  syscall(__NR_mkdir, /*path=*/0x20000300ul, /*mode=*/0ul);
  memcpy((void*)0x200000c0, "./bus\000", 6);
  memcpy((void*)0x20000080, "overlay\000", 8);
  memcpy((void*)0x20000900, "upperdir", 8);
  *(uint8_t*)0x20000908 = 0x3d;
  memcpy((void*)0x20000909, "./file1", 7);
  *(uint8_t*)0x20000910 = 0x2c;
  memcpy((void*)0x20000911, "lowerdir", 8);
  *(uint8_t*)0x20000919 = 0x3d;
  memcpy((void*)0x2000091a, "./file0", 7);
  *(uint8_t*)0x20000921 = 0x2c;
  memcpy((void*)0x20000922, "workdir", 7);
  *(uint8_t*)0x20000929 = 0x3d;
  memcpy((void*)0x2000092a, "./bus", 5);
  *(uint8_t*)0x2000092f = 0x2c;
  *(uint8_t*)0x20000930 = 0;
  syscall(__NR_mount, /*src=*/0ul, /*dst=*/0x200000c0ul, /*type=*/0x20000080ul,
          /*flags=MS_STRICTATIME*/ 0x1000000ul, /*opts=*/0x20000900ul);
  memcpy((void*)0x20000140, "./file0\000", 8);
  res = syscall(__NR_open, /*file=*/0x20000140ul, /*flags=*/0ul, /*mode=*/0ul);
  if (res != -1)
    r[0] = res;
  memcpy((void*)0x20001600, "./file1\000", 8);
  syscall(__NR_mknodat, /*dirfd=*/r[0], /*file=*/0x20001600ul, /*mode=*/0ul,
          /*dev=*/0x700);
  memcpy((void*)0x200003c0, "./bus\000", 6);
  syscall(__NR_chdir, /*dir=*/0x200003c0ul);
  memcpy((void*)0x20000100, "./file1\000", 8);
  res = syscall(__NR_openat, /*fd=*/0xffffff9c, /*file=*/0x20000100ul,
                /*flags=*/0, /*mode=S_IROTH|S_IRGRP|S_IXUSR*/ 0x64);
  if (res != -1)
    r[1] = res;
  memcpy((void*)0x20000100, "./file1\000", 8);
  memcpy((void*)0x20000240, "./file0\000", 8);
  syscall(__NR_linkat, /*oldfd=*/r[0], /*old=*/0x20000100ul, /*newfd=*/r[0],
          /*new=*/0x20000240ul, /*flags=*/0ul);
  memcpy((void*)0x20000280, "./file1\000", 8);
  syscall(__NR_unlink, /*path=*/0x20000280ul);
  inject_fault(6);
  syscall(__NR_lseek, /*fd=*/r[1], /*offset=*/0x10000ul, /*whence=*/0ul);
}
int main(void)
{
  syscall(__NR_mmap, /*addr=*/0x1ffff000ul, /*len=*/0x1000ul, /*prot=*/0ul,
          /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/-1,
          /*offset=*/0ul);
  syscall(__NR_mmap, /*addr=*/0x20000000ul, /*len=*/0x1000000ul,
          /*prot=PROT_WRITE|PROT_READ|PROT_EXEC*/ 7ul,
          /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/-1,
          /*offset=*/0ul);
  syscall(__NR_mmap, /*addr=*/0x21000000ul, /*len=*/0x1000ul, /*prot=*/0ul,
          /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/-1,
          /*offset=*/0ul);
  const char* reason;
  (void)reason;
  if ((reason = setup_fault()))
    printf("the reproducer may not work as expected: fault injection setup "
           "failed: %s\n",
           reason);
  loop();
  return 0;
}