From 947eb1fb530f5ceb562c2c2f6dd5a7113704b60f Mon Sep 17 00:00:00 2001
From: Marcin Mielniczuk <marmistrz.dev@zoho.eu>
Date: Fri, 23 Aug 2019 18:34:04 +0200
Subject: [PATCH] Move fd_advise on Linux to nix

---
 src/sys/unix/hostcalls_impl/fs.rs | 59 +++++++++++++++++--------------
 1 file changed, 32 insertions(+), 27 deletions(-)

diff --git a/src/sys/unix/hostcalls_impl/fs.rs b/src/sys/unix/hostcalls_impl/fs.rs
index 90ce9c217f..863d28e5f5 100644
--- a/src/sys/unix/hostcalls_impl/fs.rs
+++ b/src/sys/unix/hostcalls_impl/fs.rs
@@ -4,7 +4,7 @@ use super::fs_helpers::*;
 use crate::helpers::systemtime_to_timestamp;
 use crate::hostcalls_impl::PathGet;
 use crate::sys::errno_from_ioerror;
-use crate::sys::host_impl;
+use crate::sys::host_impl::{self, errno_from_nix};
 use crate::{host, Result};
 use nix::libc::{self, c_long, c_void};
 use std::convert::TryInto;
@@ -42,45 +42,50 @@ pub(crate) fn fd_fdstat_set_flags(fd: &File, fdflags: host::__wasi_fdflags_t) ->
     }
 }
 
+#[cfg(target_os = "linux")]
 pub(crate) fn fd_advise(
     file: &File,
     advice: host::__wasi_advice_t,
     offset: host::__wasi_filesize_t,
     len: host::__wasi_filesize_t,
 ) -> Result<()> {
-    #[cfg(target_os = "linux")]
     {
-        use nix::libc::off_t;
+        use nix::fcntl::{posix_fadvise, PosixFadviseAdvice};
 
+        let offset = offset.try_into().map_err(|_| host::__WASI_EOVERFLOW)?;
+        let len = len.try_into().map_err(|_| host::__WASI_EOVERFLOW)?;
         let host_advice = match advice {
-            host::__WASI_ADVICE_DONTNEED => libc::POSIX_FADV_DONTNEED,
-            host::__WASI_ADVICE_SEQUENTIAL => libc::POSIX_FADV_SEQUENTIAL,
-            host::__WASI_ADVICE_WILLNEED => libc::POSIX_FADV_DONTNEED,
-            host::__WASI_ADVICE_NOREUSE => libc::POSIX_FADV_NOREUSE,
-            host::__WASI_ADVICE_RANDOM => libc::POSIX_FADV_RANDOM,
-            host::__WASI_ADVICE_NORMAL => libc::POSIX_FADV_NORMAL,
+            host::__WASI_ADVICE_DONTNEED => PosixFadviseAdvice::POSIX_FADV_DONTNEED,
+            host::__WASI_ADVICE_SEQUENTIAL => PosixFadviseAdvice::POSIX_FADV_SEQUENTIAL,
+            host::__WASI_ADVICE_WILLNEED => PosixFadviseAdvice::POSIX_FADV_DONTNEED,
+            host::__WASI_ADVICE_NOREUSE => PosixFadviseAdvice::POSIX_FADV_NOREUSE,
+            host::__WASI_ADVICE_RANDOM => PosixFadviseAdvice::POSIX_FADV_RANDOM,
+            host::__WASI_ADVICE_NORMAL => PosixFadviseAdvice::POSIX_FADV_NORMAL,
             _ => return Err(host::__WASI_EINVAL),
         };
-        let res = unsafe {
-            libc::posix_fadvise(file.as_raw_fd(), offset as off_t, len as off_t, host_advice)
-        };
-        if res != 0 {
-            return Err(host_impl::errno_from_nix(nix::errno::Errno::last()));
-        }
+
+        posix_fadvise(file.as_raw_fd(), offset, len, host_advice)
+            .map_err(|err| errno_from_nix(err.as_errno().unwrap()))?;
     }
 
-    #[cfg(not(target_os = "linux"))]
-    {
-        let _ = (file, offset, len);
-        match advice {
-            host::__WASI_ADVICE_DONTNEED
-            | host::__WASI_ADVICE_SEQUENTIAL
-            | host::__WASI_ADVICE_WILLNEED
-            | host::__WASI_ADVICE_NOREUSE
-            | host::__WASI_ADVICE_RANDOM
-            | host::__WASI_ADVICE_NORMAL => {}
-            _ => return Err(host::__WASI_EINVAL),
-        }
+    Ok(())
+}
+
+#[cfg(not(target_os = "linux"))]
+pub(crate) fn fd_advise(
+    _file: &File,
+    advice: host::__wasi_advice_t,
+    _offset: host::__wasi_filesize_t,
+    _len: host::__wasi_filesize_t,
+) -> Result<()> {
+    match advice {
+        host::__WASI_ADVICE_DONTNEED
+        | host::__WASI_ADVICE_SEQUENTIAL
+        | host::__WASI_ADVICE_WILLNEED
+        | host::__WASI_ADVICE_NOREUSE
+        | host::__WASI_ADVICE_RANDOM
+        | host::__WASI_ADVICE_NORMAL => {}
+        _ => return Err(host::__WASI_EINVAL),
     }
 
     Ok(())