content: # Tests for recovering from conditions which shouldn't normally
  # happen during normal operation of littlefs
  
  # invalid pointer tests (outside of block_count)
  
  [cases.test_evil_invalid_tail_pointer]
  defines.TAIL_TYPE = ['LFS_TYPE_HARDTAIL', 'LFS_TYPE_SOFTTAIL']
  defines.INVALSET = [0x3, 0x1, 0x2]
  in = "lfs.c"
  code = '''
      // create littlefs
      lfs_t lfs;
      lfs_format(&lfs, cfg) => 0;
  
      // change tail-pointer to invalid pointers
      lfs_init(&lfs, cfg) => 0;
      lfs_mdir_t mdir;
      lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
      lfs_dir_commit(&lfs, &mdir, LFS_MKATTRS(
              {LFS_MKTAG(LFS_TYPE_HARDTAIL, 0x3ff, 8),
                  (lfs_block_t[2]){
                      (INVALSET & 0x1) ? 0xcccccccc : 0,
                      (INVALSET & 0x2) ? 0xcccccccc : 0}})) => 0;
      lfs_deinit(&lfs) => 0;
  
      // test that mount fails gracefully
      lfs_mount(&lfs, cfg) => LFS_ERR_CORRUPT;
  '''
  
  [cases.test_evil_invalid_dir_pointer]
  defines.INVALSET = [0x3, 0x1, 0x2]
  in = "lfs.c"
  code = '''
      // create littlefs
      lfs_t lfs;
      lfs_format(&lfs, cfg) => 0;
      // make a dir
      lfs_mount(&lfs, cfg) => 0;
      lfs_mkdir(&lfs, "dir_here") => 0;
      lfs_unmount(&lfs) => 0;
  
      // change the dir pointer to be invalid
      lfs_init(&lfs, cfg) => 0;
      lfs_mdir_t mdir;
      lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
      // make sure id 1 == our directory
      uint8_t buffer[1024];
      lfs_dir_get(&lfs, &mdir,
              LFS_MKTAG(0x700, 0x3ff, 0),
              LFS_MKTAG(LFS_TYPE_NAME, 1, strlen("dir_here")), buffer)
                  => LFS_MKTAG(LFS_TYPE_DIR, 1, strlen("dir_here"));
      assert(memcmp((char*)buffer, "dir_here", strlen("dir_here")) == 0);
      // change dir pointer
      lfs_dir_commit(&lfs, &mdir, LFS_MKATTRS(
              {LFS_MKTAG(LFS_TYPE_DIRSTRUCT, 1, 8),
                  (lfs_block_t[2]){
                      (INVALSET & 0x1) ? 0xcccccccc : 0,
                      (INVALSET & 0x2) ? 0xcccccccc : 0}})) => 0;
      lfs_deinit(&lfs) => 0;
  
      // test that accessing our bad dir fails, note there's a number
      // of ways to access the dir, some can fail, but some don't
      lfs_mount(&lfs, cfg) => 0;
      struct lfs_info info;
      lfs_stat(&lfs, "dir_here", &info) => 0;
      assert(strcmp(info.name, "dir_here") == 0);
      assert(info.type == LFS_TYPE_DIR);
  
      lfs_dir_t dir;
      lfs_dir_open(&lfs, &dir, "dir_here") => LFS_ERR_CORRUPT;
      lfs_stat(&lfs, "dir_here/file_here", &info) => LFS_ERR_CORRUPT;
      lfs_dir_open(&lfs, &dir, "dir_here/dir_here") => LFS_ERR_CORRUPT;
      lfs_file_t file;
      lfs_file_open(&lfs, &file, "dir_here/file_here",
              LFS_O_RDONLY) => LFS_ERR_CORRUPT;
      lfs_file_open(&lfs, &file, "dir_here/file_here",
              LFS_O_WRONLY | LFS_O_CREAT) => LFS_ERR_CORRUPT;
      lfs_unmount(&lfs) => 0;
  '''
  
  [cases.test_evil_invalid_file_pointer]
  in = "lfs.c"
  defines.SIZE = [10, 1000, 100000] # faked file size
  code = '''
      // create littlefs
      lfs_t lfs;
      lfs_format(&lfs, cfg) => 0;
      // make a file
      lfs_mount(&lfs, cfg) => 0;
      lfs_file_t file;
      lfs_file_open(&lfs, &file, "file_here",
              LFS_O_WRONLY | LFS_O_CREAT) => 0;
      lfs_file_close(&lfs, &file) => 0;
      lfs_unmount(&lfs) => 0;
  
      // change the file pointer to be invalid
      lfs_init(&lfs, cfg) => 0;
      lfs_mdir_t mdir;
      lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
      // make sure id 1 == our file
      uint8_t buffer[1024];
      lfs_dir_get(&lfs, &mdir,
              LFS_MKTAG(0x700, 0x3ff, 0),
              LFS_MKTAG(LFS_TYPE_NAME, 1, strlen("file_here")), buffer)
                  => LFS_MKTAG(LFS_TYPE_REG, 1, strlen("file_here"));
      assert(memcmp((char*)buffer, "file_here", strlen("file_here")) == 0);
      // change file pointer
      lfs_dir_commit(&lfs, &mdir, LFS_MKATTRS(
              {LFS_MKTAG(LFS_TYPE_CTZSTRUCT, 1, sizeof(struct lfs_ctz)),
                  &(struct lfs_ctz){0xcccccccc, lfs_tole32(SIZE)}})) => 0;
      lfs_deinit(&lfs) => 0;
  
      // test that accessing our bad file fails, note there's a number
      // of ways to access the dir, some can fail, but some don't
      lfs_mount(&lfs, cfg) => 0;
      struct lfs_info info;
      lfs_stat(&lfs, "file_here", &info) => 0;
      assert(strcmp(info.name, "file_here") == 0);
      assert(info.type == LFS_TYPE_REG);
      assert(info.size == SIZE);
  
      lfs_file_open(&lfs, &file, "file_here", LFS_O_RDONLY) => 0;
      lfs_file_read(&lfs, &file, buffer, SIZE) => LFS_ERR_CORRUPT;
      lfs_file_close(&lfs, &file) => 0;
  
      // any allocs that traverse CTZ must unfortunately must fail
      if (SIZE > 2*BLOCK_SIZE) {
          lfs_mkdir(&lfs, "dir_here") => LFS_ERR_CORRUPT;
      }
      lfs_unmount(&lfs) => 0;
  '''
  
  [cases.test_evil_invalid_ctz_pointer] # invalid pointer in CTZ skip-list test
  defines.SIZE = ['2*BLOCK_SIZE', '3*BLOCK_SIZE', '4*BLOCK_SIZE']
  in = "lfs.c"
  code = '''
      // create littlefs
      lfs_t lfs;
      lfs_format(&lfs, cfg) => 0;
      // make a file
      lfs_mount(&lfs, cfg) => 0;
      lfs_file_t file;
      lfs_file_open(&lfs, &file, "file_here",
              LFS_O_WRONLY | LFS_O_CREAT) => 0;
      for (int i = 0; i < SIZE; i++) {
          char c = 'c';
          lfs_file_write(&lfs, &file, &c, 1) => 1;
      }
      lfs_file_close(&lfs, &file) => 0;
      lfs_unmount(&lfs) => 0;
      // change pointer in CTZ skip-list to be invalid
      lfs_init(&lfs, cfg) => 0;
      lfs_mdir_t mdir;
      lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
      // make sure id 1 == our file and get our CTZ structure
      uint8_t buffer[4*BLOCK_SIZE];
      lfs_dir_get(&lfs, &mdir,
              LFS_MKTAG(0x700, 0x3ff, 0),
              LFS_MKTAG(LFS_TYPE_NAME, 1, strlen("file_here")), buffer)
                  => LFS_MKTAG(LFS_TYPE_REG, 1, strlen("file_here"));
      assert(memcmp((char*)buffer, "file_here", strlen("file_here")) == 0);
      struct lfs_ctz ctz;
      lfs_dir_get(&lfs, &mdir,
              LFS_MKTAG(0x700, 0x3ff, 0),
              LFS_MKTAG(LFS_TYPE_STRUCT, 1, sizeof(struct lfs_ctz)), &ctz)
                  => LFS_MKTAG(LFS_TYPE_CTZSTRUCT, 1, sizeof(struct lfs_ctz));
      lfs_ctz_fromle32(&ctz);
      // rewrite block to contain bad pointer
      uint8_t bbuffer[BLOCK_SIZE];
      cfg->read(cfg, ctz.head, 0, bbuffer, BLOCK_SIZE) => 0;
      uint32_t bad = lfs_tole32(0xcccccccc);
      memcpy(&bbuffer[0], &bad, sizeof(bad));
      memcpy(&bbuffer[4], &bad, sizeof(bad));
      cfg->erase(cfg, ctz.head) => 0;
      cfg->prog(cfg, ctz.head, 0, bbuffer, BLOCK_SIZE) => 0;
      lfs_deinit(&lfs) => 0;
  
      // test that accessing our bad file fails, note there's a number
      // of ways to access the dir, some can fail, but some don't
      lfs_mount(&lfs, cfg) => 0;
      struct lfs_info info;
      lfs_stat(&lfs, "file_here", &info) => 0;
      assert(strcmp(info.name, "file_here") == 0);
      assert(info.type == LFS_TYPE_REG);
      assert(info.size == SIZE);
  
      lfs_file_open(&lfs, &file, "file_here", LFS_O_RDONLY) => 0;
      lfs_file_read(&lfs, &file, buffer, SIZE) => LFS_ERR_CORRUPT;
      lfs_file_close(&lfs, &file) => 0;
  
      // any allocs that traverse CTZ must unfortunately must fail
      if (SIZE > 2*BLOCK_SIZE) {
          lfs_mkdir(&lfs, "dir_here") => LFS_ERR_CORRUPT;
      }
      lfs_unmount(&lfs) => 0;
  '''
  
  
  [cases.test_evil_invalid_gstate_pointer]
  defines.INVALSET = [0x3, 0x1, 0x2]
  in = "lfs.c"
  code = '''
      // create littlefs
      lfs_t lfs;
      lfs_format(&lfs, cfg) => 0;
  
      // create an invalid gstate
      lfs_init(&lfs, cfg) => 0;
      lfs_mdir_t mdir;
      lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
      lfs_fs_prepmove(&lfs, 1, (lfs_block_t [2]){
              (INVALSET & 0x1) ? 0xcccccccc : 0,
              (INVALSET & 0x2) ? 0xcccccccc : 0});
      lfs_dir_commit(&lfs, &mdir, NULL, 0) => 0;
      lfs_deinit(&lfs) => 0;
  
      // test that mount fails gracefully
      // mount may not fail, but our first alloc should fail when
      // we try to fix the gstate
      lfs_mount(&lfs, cfg) => 0;
      lfs_mkdir(&lfs, "should_fail") => LFS_ERR_CORRUPT;
      lfs_unmount(&lfs) => 0;
  '''
  
  # cycle detection/recovery tests
  
  [cases.test_evil_mdir_loop] # metadata-pair threaded-list loop test
  in = "lfs.c"
  code = '''
      // create littlefs
      lfs_t lfs;
      lfs_format(&lfs, cfg) => 0;
  
      // change tail-pointer to point to ourself
      lfs_init(&lfs, cfg) => 0;
      lfs_mdir_t mdir;
      lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
      lfs_dir_commit(&lfs, &mdir, LFS_MKATTRS(
              {LFS_MKTAG(LFS_TYPE_HARDTAIL, 0x3ff, 8),
                  (lfs_block_t[2]){0, 1}})) => 0;
      lfs_deinit(&lfs) => 0;
  
      // test that mount fails gracefully
      lfs_mount(&lfs, cfg) => LFS_ERR_CORRUPT;
  '''
  
  [cases.test_evil_mdir_loop2] # metadata-pair threaded-list 2-length loop test
  in = "lfs.c"
  code = '''
      // create littlefs with child dir
      lfs_t lfs;
      lfs_format(&lfs, cfg) => 0;
      lfs_mount(&lfs, cfg) => 0;
      lfs_mkdir(&lfs, "child") => 0;
      lfs_unmount(&lfs) => 0;
  
      // find child
      lfs_init(&lfs, cfg) => 0;
      lfs_mdir_t mdir;
      lfs_block_t pair[2];
      lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
      lfs_dir_get(&lfs, &mdir,
              LFS_MKTAG(0x7ff, 0x3ff, 0),
              LFS_MKTAG(LFS_TYPE_DIRSTRUCT, 1, sizeof(pair)), pair)
                  => LFS_MKTAG(LFS_TYPE_DIRSTRUCT, 1, sizeof(pair));
      lfs_pair_fromle32(pair);
      // change tail-pointer to point to root
      lfs_dir_fetch(&lfs, &mdir, pair) => 0;
      lfs_dir_commit(&lfs, &mdir, LFS_MKATTRS(
              {LFS_MKTAG(LFS_TYPE_HARDTAIL, 0x3ff, 8),
                  (lfs_block_t[2]){0, 1}})) => 0;
      lfs_deinit(&lfs) => 0;
  
      // test that mount fails gracefully
      lfs_mount(&lfs, cfg) => LFS_ERR_CORRUPT;
  '''
  
  [cases.test_evil_mdir_loop_child] # metadata-pair threaded-list 1-length child loop test
  in = "lfs.c"
  code = '''
      // create littlefs with child dir
      lfs_t lfs;
      lfs_format(&lfs, cfg) => 0;
      lfs_mount(&lfs, cfg) => 0;
      lfs_mkdir(&lfs, "child") => 0;
      lfs_unmount(&lfs) => 0;
  
      // find child
      lfs_init(&lfs, cfg) => 0;
      lfs_mdir_t mdir;
      lfs_block_t pair[2];
      lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
      lfs_dir_get(&lfs, &mdir,
              LFS_MKTAG(0x7ff, 0x3ff, 0),
              LFS_MKTAG(LFS_TYPE_DIRSTRUCT, 1, sizeof(pair)), pair)
                  => LFS_MKTAG(LFS_TYPE_DIRSTRUCT, 1, sizeof(pair));
      lfs_pair_fromle32(pair);
      // change tail-pointer to point to ourself
      lfs_dir_fetch(&lfs, &mdir, pair) => 0;
      lfs_dir_commit(&lfs, &mdir, LFS_MKATTRS(
              {LFS_MKTAG(LFS_TYPE_HARDTAIL, 0x3ff, 8), pair})) => 0;
      lfs_deinit(&lfs) => 0;
  
      // test that mount fails gracefully
      lfs_mount(&lfs, cfg) => LFS_ERR_CORRUPT;
  '''
  