Change Details

When `closefrom` is not available, it uses `get_max_fds`. `get_max_fds` implementation has following issues: - TRACE may calls non-async-signal-safe function, may result hang (in multithread application) - sysconf is not async-signal-safe function, may result hang (in multithread application) - `syscall` return type is `long`. For 64-bit arch, it has unseen type conversion from `long` to `int`, which is difficult to read. Use of `long` for `r` and `pos` is good. - On a machine which doesn't allow unaligned access, `dir_buf` should be aligned properly (`__attribute__ ((aligned (8))`). `getdents64` itself would be OK for the kernel (glibc documentation seems to say so) with unaligned buf, but `dir_entry->d_reclen` is not.

When `closefrom` is not available, it uses `get_max_fds`. `get_max_fds` implementation has following issues: - return type mismatch: `int` is good - TRACE may calls non-async-signal-safe function, may result hang (in multithread application) - sysconf is not async-signal-safe function, may result hang (in multithread application) - `syscall` return type is `long`. For 64-bit arch, it has unseen type conversion from `long` to `int`, which is difficult to read. Use of `long` for `r` and `pos` is good. - On a machine which doesn't allow unaligned access, `dir_buf` should be aligned properly (`__attribute__ ((aligned (8))`). `getdents64` itself would be OK for the kernel (glibc documentation seems to say so) with unaligned buf, but `dir_entry->d_reclen` is not.

When `closefrom` is not available, it uses `get_max_fds`. `get_max_fds` implementation has following issues: - return type mismatch: `int` is good - TRACE may calls non-async-signal-safe function, may result hang (in multithread application) - sysconf is not async-signal-safe function, may result hang (in multithread application) - `syscall` return type is `long`. For 64-bit arch, it has unseen type conversion from `long` to `int`, which is difficult to read. Use of `long` for `r` and `pos` is good. - On a machine which doesn't allow unaligned access, `dir_buf` should be aligned properly (`__attribute__ ((aligned (8))`). `getdents64` itself would be OK for the kernel (glibc documentation seems to say so) with unaligned buf, but `dir_entry->d_reclen` is not.