// https://syzkaller.appspot.com/bug?id=3c9363c29856ca346f6ca0e9efc6745f12687d18
// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <dirent.h>
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <sched.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/ioctl.h>
#include <sys/mount.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>

#ifndef __NR_pidfd_open
#define __NR_pidfd_open 434
#endif

static __thread int clone_ongoing;
static __thread int skip_segv;
static __thread jmp_buf segv_env;

static void segv_handler(int sig, siginfo_t* info, void* ctx)
{
  if (__atomic_load_n(&clone_ongoing, __ATOMIC_RELAXED) != 0) {
    exit(sig);
  }
  uintptr_t addr = (uintptr_t)info->si_addr;
  const uintptr_t prog_start = 1 << 20;
  const uintptr_t prog_end = 100 << 20;
  int skip = __atomic_load_n(&skip_segv, __ATOMIC_RELAXED) != 0;
  int valid = addr < prog_start || addr > prog_end;
  if (skip && valid) {
    _longjmp(segv_env, 1);
  }
  exit(sig);
}

static void install_segv_handler(void)
{
  struct sigaction sa;
  memset(&sa, 0, sizeof(sa));
  sa.sa_handler = SIG_IGN;
  syscall(SYS_rt_sigaction, 0x20, &sa, NULL, 8);
  syscall(SYS_rt_sigaction, 0x21, &sa, NULL, 8);
  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(...)                                                        \
  ({                                                                           \
    int ok = 1;                                                                \
    __atomic_fetch_add(&skip_segv, 1, __ATOMIC_SEQ_CST);                       \
    if (_setjmp(segv_env) == 0) {                                              \
      __VA_ARGS__;                                                             \
    } else                                                                     \
      ok = 0;                                                                  \
    __atomic_fetch_sub(&skip_segv, 1, __ATOMIC_SEQ_CST);                       \
    ok;                                                                        \
  })

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 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;
}

#define FS_IOC_SETFLAGS _IOW('f', 2, long)
static void remove_dir(const char* dir)
{
  int iter = 0;
  DIR* dp = 0;
  const int umount_flags = MNT_FORCE | UMOUNT_NOFOLLOW;

retry:
  while (umount2(dir, umount_flags) == 0) {
  }
  dp = opendir(dir);
  if (dp == NULL) {
    if (errno == EMFILE) {
      exit(1);
    }
    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);
    while (umount2(filename, umount_flags) == 0) {
    }
    struct stat st;
    if (lstat(filename, &st))
      exit(1);
    if (S_ISDIR(st.st_mode)) {
      remove_dir(filename);
      continue;
    }
    int i;
    for (i = 0;; i++) {
      if (unlink(filename) == 0)
        break;
      if (errno == EPERM) {
        int fd = open(filename, O_RDONLY);
        if (fd != -1) {
          long flags = 0;
          if (ioctl(fd, FS_IOC_SETFLAGS, &flags) == 0) {
          }
          close(fd);
          continue;
        }
      }
      if (errno == EROFS) {
        break;
      }
      if (errno != EBUSY || i > 100)
        exit(1);
      if (umount2(filename, umount_flags))
        exit(1);
    }
  }
  closedir(dp);
  for (int i = 0;; i++) {
    if (rmdir(dir) == 0)
      break;
    if (i < 100) {
      if (errno == EPERM) {
        int fd = open(dir, O_RDONLY);
        if (fd != -1) {
          long flags = 0;
          if (ioctl(fd, FS_IOC_SETFLAGS, &flags) == 0) {
          }
          close(fd);
          continue;
        }
      }
      if (errno == EROFS) {
        break;
      }
      if (errno == EBUSY) {
        if (umount2(dir, umount_flags))
          exit(1);
        continue;
      }
      if (errno == ENOTEMPTY) {
        if (iter < 100) {
          iter++;
          goto retry;
        }
      }
    }
    exit(1);
  }
}

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");
  if (symlink("/dev/binderfs", "./binderfs")) {
  }
}

#define USLEEP_FORKED_CHILD (3 * 50 * 1000)

static long handle_clone_ret(long ret)
{
  if (ret != 0) {
    __atomic_store_n(&clone_ongoing, 0, __ATOMIC_RELAXED);
    return ret;
  }
  usleep(USLEEP_FORKED_CHILD);
  syscall(__NR_exit, 0);
  while (1) {
  }
}

static long syz_clone(volatile long flags, volatile long stack,
                      volatile long stack_len, volatile long ptid,
                      volatile long ctid, volatile long tls)
{
  long sp = (stack + stack_len) & ~15;
  __atomic_store_n(&clone_ongoing, 1, __ATOMIC_RELAXED);
  long ret = (long)syscall(__NR_clone, flags & ~CLONE_VM, sp, ptid, ctid, tls);
  return handle_clone_ret(ret);
}

static long syz_pidfd_open(volatile long pid, volatile long flags)
{
  if (pid == 1) {
    pid = 0;
  }
  return syscall(__NR_pidfd_open, pid, flags);
}

static void execute_one(void);

#define WAIT_FLAGS __WALL

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);
      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;
    }
    remove_dir(cwdbuf);
  }
}

uint64_t r[2] = {0x0, 0xffffffffffffffff};

void execute_one(void)
{
  intptr_t res = 0;
  if (write(1, "executing program\n", sizeof("executing program\n") - 1)) {
  }
  //  mkdir arguments: [
  //    path: ptr[in, buffer] {
  //      buffer: {2e 2f 66 69 6c 65 30 00} (length 0x8)
  //    }
  //    mode: open_mode = 0x0 (8 bytes)
  //  ]
  NONFAILING(memcpy((void*)0x200000000140, "./file0\000", 8));
  syscall(__NR_mkdir, /*path=*/0x200000000140ul, /*mode=*/0ul);
  //  mount arguments: [
  //    src: nil
  //    dst: ptr[in, buffer] {
  //      buffer: {2e 2f 66 69 6c 65 30 00} (length 0x8)
  //    }
  //    type: ptr[in, buffer] {
  //      buffer: {72 61 6d 66 73 00} (length 0x6)
  //    }
  //    flags: mount_flags = 0x2800000 (8 bytes)
  //    data: nil
  //  ]
  NONFAILING(memcpy((void*)0x200000000100, "./file0\000", 8));
  NONFAILING(memcpy((void*)0x200000000400, "ramfs\000", 6));
  syscall(__NR_mount, /*src=*/0ul, /*dst=*/0x200000000100ul,
          /*type=*/0x200000000400ul,
          /*flags=MS_LAZYTIME|MS_I_VERSION*/ 0x2800000ul, /*data=*/0ul);
  //  mount$incfs arguments: [
  //    src: ptr[in, buffer] {
  //      buffer: {2e 2f 66 69 6c 65 30 00} (length 0x8)
  //    }
  //    dst: ptr[in, buffer] {
  //      buffer: {2e 2f 66 69 6c 65 30 00} (length 0x8)
  //    }
  //    type: ptr[in, buffer] {
  //      buffer: {69 6e 63 72 65 6d 65 6e 74 61 6c 2d 66 73 00} (length 0xf)
  //    }
  //    flags: mount_flags = 0x2010800 (8 bytes)
  //    opts: nil
  //  ]
  NONFAILING(memcpy((void*)0x200000000080, "./file0\000", 8));
  NONFAILING(memcpy((void*)0x200000000140, "./file0\000", 8));
  NONFAILING(memcpy((void*)0x200000000680, "incremental-fs\000", 15));
  syscall(__NR_mount, /*src=*/0x200000000080ul, /*dst=*/0x200000000140ul,
          /*type=*/0x200000000680ul,
          /*flags=MS_LAZYTIME|MS_POSIXACL|MS_NODIRATIME*/ 0x2010800ul,
          /*opts=*/0ul);
  //  getpid arguments: [
  //  ]
  //  returns pid
  res = syscall(__NR_getpid);
  if (res != -1)
    r[0] = res;
  //  syz_pidfd_open arguments: [
  //    pid: pid (resource)
  //    flags: const = 0x0 (8 bytes)
  //  ]
  //  returns fd_pidfd
  res = -1;
  NONFAILING(res = syz_pidfd_open(/*pid=*/r[0], /*flags=*/0));
  if (res != -1)
    r[1] = res;
  //  setns arguments: [
  //    fd: fd_namespace (resource)
  //    type: ns_type = 0x24020000 (8 bytes)
  //  ]
  syscall(__NR_setns, /*fd=*/r[1],
          /*type=CLONE_NEWPID|CLONE_NEWNS|CLONE_NEWUTS*/ 0x24020000ul);
  //  syz_clone arguments: [
  //    flags: clone_flags = 0xb21e0000 (8 bytes)
  //    stack: nil
  //    stack_len: bytesize = 0x0 (8 bytes)
  //    parentid: nil
  //    childtid: nil
  //    tls: nil
  //  ]
  //  returns pid
  NONFAILING(syz_clone(
      /*flags=CLONE_IO|CLONE_NEWPID|CLONE_NEWUSER|CLONE_NEWCGROUP|CLONE_PARENT_SETTID|0xe0000*/
      0xb21e0000, /*stack=*/0, /*stack_len=*/0, /*parentid=*/0, /*childtid=*/0,
      /*tls=*/0));
}
int main(void)
{
  syscall(__NR_mmap, /*addr=*/0x1ffffffff000ul, /*len=*/0x1000ul, /*prot=*/0ul,
          /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul,
          /*fd=*/(intptr_t)-1, /*offset=*/0ul);
  syscall(__NR_mmap, /*addr=*/0x200000000000ul, /*len=*/0x1000000ul,
          /*prot=PROT_WRITE|PROT_READ|PROT_EXEC*/ 7ul,
          /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul,
          /*fd=*/(intptr_t)-1, /*offset=*/0ul);
  syscall(__NR_mmap, /*addr=*/0x200001000000ul, /*len=*/0x1000ul, /*prot=*/0ul,
          /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul,
          /*fd=*/(intptr_t)-1, /*offset=*/0ul);
  const char* reason;
  (void)reason;
  install_segv_handler();
  use_temporary_dir();
  loop();
  return 0;
}