From 917a9affc114b68ef4985511bdee106429bbf2ac Mon Sep 17 00:00:00 2001 From: Alex Crichton Date: Sun, 25 Dec 2016 21:57:32 -0800 Subject: std: Clamp max read/write sizes on Unix Turns out that even though all these functions take a `size_t` they don't actually work that well with anything larger than the maximum value of `ssize_t`, the return value. Furthermore it looks like OSX rejects any read/write requests larger than `INT_MAX - 1`. Handle all these cases by just clamping the maximum size of a read/write on Unix to a platform-specific value. Closes #38590 --- src/libstd/sys/windows/handle.rs | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) (limited to 'src/libstd/sys/windows') diff --git a/src/libstd/sys/windows/handle.rs b/src/libstd/sys/windows/handle.rs index 10b86ba44bc..fdb9483fe1c 100644 --- a/src/libstd/sys/windows/handle.rs +++ b/src/libstd/sys/windows/handle.rs @@ -19,7 +19,6 @@ use ptr; use sys::c; use sys::cvt; use sys_common::io::read_to_end_uninitialized; -use u32; /// An owned container for `HANDLE` object, closing them on Drop. /// @@ -83,9 +82,7 @@ impl RawHandle { pub fn read(&self, buf: &mut [u8]) -> io::Result { let mut read = 0; - // ReadFile takes a DWORD (u32) for the length so it only supports - // reading u32::MAX bytes at a time. - let len = cmp::min(buf.len(), u32::MAX as usize) as c::DWORD; + let len = cmp::min(buf.len(), ::max_value() as usize) as c::DWORD; let res = cvt(unsafe { c::ReadFile(self.0, buf.as_mut_ptr() as c::LPVOID, len, &mut read, ptr::null_mut()) @@ -181,9 +178,7 @@ impl RawHandle { pub fn write(&self, buf: &[u8]) -> io::Result { let mut amt = 0; - // WriteFile takes a DWORD (u32) for the length so it only supports - // writing u32::MAX bytes at a time. - let len = cmp::min(buf.len(), u32::MAX as usize) as c::DWORD; + let len = cmp::min(buf.len(), ::max_value() as usize) as c::DWORD; cvt(unsafe { c::WriteFile(self.0, buf.as_ptr() as c::LPVOID, len, &mut amt, ptr::null_mut()) -- cgit 1.4.1-3-g733a5