From 6d999151548fd9ae0de19f4f7d2767cca2e00448 Mon Sep 17 00:00:00 2001
From: jD91mZM2 <me@krake.one>
Date: Sun, 23 Sep 2018 20:38:55 +0200
Subject: [PATCH] Use RAII for file locking in stdio
---
src/header/stdio/mod.rs | 106 +++++++++++++++++-----------------------
1 file changed, 44 insertions(+), 62 deletions(-)
diff --git a/src/header/stdio/mod.rs b/src/header/stdio/mod.rs
index 39d097fe..399a4445 100644
--- a/src/header/stdio/mod.rs
+++ b/src/header/stdio/mod.rs
@@ -3,7 +3,8 @@
use alloc::vec::Vec;
use core::fmt::Write as WriteFmt;
use core::fmt::{self, Error};
-use core::sync::atomic::{AtomicBool, Ordering};
+use core::ops::{Deref, DerefMut};
+use core::sync::atomic::{self, AtomicBool, Ordering};
use core::{ptr, str};
use va_list::VaList as va_list;
@@ -187,6 +188,18 @@ impl FILE {
}
pub struct LockGuard<'a>(&'a mut FILE);
+impl<'a> Deref for LockGuard<'a> {
+ type Target = &'a mut FILE;
+
+ fn deref(&self) -> &Self::Target {
+ &self.0
+ }
+}
+impl<'a> DerefMut for LockGuard<'a> {
+ fn deref_mut(&mut self) -> &mut Self::Target {
+ &mut self.0
+ }
+}
impl<'a> Drop for LockGuard<'a> {
fn drop(&mut self) {
funlockfile(self.0);
@@ -286,19 +299,15 @@ pub extern "C" fn fdopen(fildes: c_int, mode: *const c_char) -> *mut FILE {
/// Check for EOF
#[no_mangle]
pub extern "C" fn feof(stream: &mut FILE) -> c_int {
- flockfile(stream);
- let ret = stream.flags & F_EOF;
- funlockfile(stream);
- ret
+ let stream = stream.lock();
+ stream.flags & F_EOF
}
/// Check for ERR
#[no_mangle]
pub extern "C" fn ferror(stream: &mut FILE) -> c_int {
- flockfile(stream);
- let ret = stream.flags & F_ERR;
- funlockfile(stream);
- ret
+ let stream = stream.lock();
+ stream.flags & F_ERR
}
/// Flush output to stream, or sync read position
@@ -306,19 +315,15 @@ pub extern "C" fn ferror(stream: &mut FILE) -> c_int {
/// itself.
#[no_mangle]
pub unsafe extern "C" fn fflush(stream: &mut FILE) -> c_int {
- flockfile(stream);
- let ret = helpers::fflush_unlocked(stream);
- funlockfile(stream);
- ret
+ let mut stream = stream.lock();
+ helpers::fflush_unlocked(&mut stream)
}
/// Get a single char from a stream
#[no_mangle]
pub extern "C" fn fgetc(stream: &mut FILE) -> c_int {
- flockfile(stream);
- let c = getc_unlocked(stream);
- funlockfile(stream);
- c
+ let mut stream = stream.lock();
+ getc_unlocked(&mut stream)
}
/// Get the position of the stream and store it in pos
@@ -340,14 +345,13 @@ pub extern "C" fn fgetpos(stream: &mut FILE, pos: Option<&mut fpos_t>) -> c_int
#[no_mangle]
pub extern "C" fn fgets(s: *mut c_char, n: c_int, stream: &mut FILE) -> *mut c_char {
use core::slice;
- flockfile(stream);
+ let mut stream = stream.lock();
let st = unsafe { slice::from_raw_parts_mut(s as *mut u8, n as usize) };
let mut len = n;
// We can only fit one or less chars in
if n <= 1 {
- funlockfile(stream);
if n <= 0 {
return ptr::null_mut();
}
@@ -360,7 +364,6 @@ pub extern "C" fn fgets(s: *mut c_char, n: c_int, stream: &mut FILE) -> *mut c_c
{
// We can't read from this stream
if !stream.can_read() {
- funlockfile(stream);
return ptr::null_mut();
}
}
@@ -399,17 +402,14 @@ pub extern "C" fn fgets(s: *mut c_char, n: c_int, stream: &mut FILE) -> *mut c_c
}
st[(n - len) as usize] = 0;
- funlockfile(stream);
s
}
/// Get the underlying file descriptor
#[no_mangle]
pub extern "C" fn fileno(stream: &mut FILE) -> c_int {
- flockfile(stream);
- let fd = stream.fd;
- funlockfile(stream);
- fd
+ let stream = stream.lock();
+ stream.fd
}
/// Lock the file
@@ -417,7 +417,9 @@ pub extern "C" fn fileno(stream: &mut FILE) -> c_int {
/// locked
#[no_mangle]
pub extern "C" fn flockfile(file: &mut FILE) {
- while ftrylockfile(file) != 0 {}
+ while ftrylockfile(file) != 0 {
+ atomic::spin_loop_hint();
+ }
}
/// Open the file in mode `mode`
@@ -458,10 +460,8 @@ pub extern "C" fn fopen(filename: *const c_char, mode: *const c_char) -> *mut FI
/// Insert a character into the stream
#[no_mangle]
pub extern "C" fn fputc(c: c_int, stream: &mut FILE) -> c_int {
- flockfile(stream);
- let c = putc_unlocked(c, stream);
- funlockfile(stream);
- c
+ let mut stream = stream.lock();
+ putc_unlocked(c, &mut stream)
}
/// Insert a string into a stream
@@ -480,10 +480,9 @@ pub extern "C" fn fread(ptr: *mut c_void, size: usize, nitems: usize, stream: &m
let len = size * nitems;
let mut l = len as isize;
- flockfile(stream);
+ let mut stream = stream.lock();
if !stream.can_read() {
- funlockfile(stream);
return 0;
}
@@ -510,7 +509,6 @@ pub extern "C" fn fread(ptr: *mut c_void, size: usize, nitems: usize, stream: &m
};
if k == 0 {
- funlockfile(stream);
return (len - l as usize) / 2;
}
@@ -521,7 +519,6 @@ pub extern "C" fn fread(ptr: *mut c_void, size: usize, nitems: usize, stream: &m
}
}
- funlockfile(stream);
nitems
} else {
unreachable!()
@@ -545,14 +542,12 @@ pub extern "C" fn freopen(
}
flags &= !(fcntl::O_CREAT | fcntl::O_EXCL | fcntl::O_CLOEXEC);
if fcntl::sys_fcntl(stream.fd, fcntl::F_SETFL, flags) < 0 {
- funlockfile(stream);
fclose(stream);
return ptr::null_mut();
}
} else {
let new = fopen(filename, mode);
if new.is_null() {
- funlockfile(stream);
fclose(stream);
return ptr::null_mut();
}
@@ -563,14 +558,12 @@ pub extern "C" fn freopen(
|| fcntl::sys_fcntl(stream.fd, fcntl::F_SETFL, flags & fcntl::O_CLOEXEC) < 0
{
fclose(new);
- funlockfile(stream);
fclose(stream);
return ptr::null_mut();
}
stream.flags = (stream.flags & constants::F_PERM) | new.flags;
fclose(new);
}
- funlockfile(stream);
stream
}
@@ -587,7 +580,8 @@ pub extern "C" fn fseek(stream: &mut FILE, offset: c_long, whence: c_int) -> c_i
#[no_mangle]
pub extern "C" fn fseeko(stream: &mut FILE, offset: off_t, whence: c_int) -> c_int {
let mut off = offset;
- flockfile(stream);
+ let mut stream = stream.lock();
+
// Adjust for what is currently in the buffer
let rdiff = if let Some((rpos, rend)) = stream.read {
rend - rpos
@@ -602,12 +596,10 @@ pub extern "C" fn fseeko(stream: &mut FILE, offset: off_t, whence: c_int) -> c_i
}
stream.write = None;
if stream.seek(off, whence) < 0 {
- funlockfile(stream);
return -1;
}
stream.read = None;
stream.flags &= !F_EOF;
- funlockfile(stream);
0
}
@@ -630,10 +622,8 @@ pub extern "C" fn ftell(stream: &mut FILE) -> c_long {
/// Get the current position of the cursor in the file
#[no_mangle]
pub extern "C" fn ftello(stream: &mut FILE) -> off_t {
- flockfile(stream);
- let pos = internal::ftello(stream);
- funlockfile(stream);
- pos
+ let mut stream = stream.lock();
+ internal::ftello(&mut stream)
}
/// Try to lock the file. Returns 0 for success, 1 for failure
@@ -658,9 +648,8 @@ pub extern "C" fn fwrite(
) -> usize {
let l = size * nitems;
let nitems = if size == 0 { 0 } else { nitems };
- flockfile(stream);
- let k = helpers::fwritex(ptr as *const u8, l, stream);
- funlockfile(stream);
+ let mut stream = stream.lock();
+ let k = helpers::fwritex(ptr as *const u8, l, &mut stream);
if k == l {
nitems
} else {
@@ -671,10 +660,8 @@ pub extern "C" fn fwrite(
/// Get a single char from a stream
#[no_mangle]
pub extern "C" fn getc(stream: &mut FILE) -> c_int {
- flockfile(stream);
- let c = getc_unlocked(stream);
- funlockfile(stream);
- c
+ let mut stream = stream.lock();
+ getc_unlocked(&mut stream)
}
/// Get a single char from `stdin`
@@ -768,10 +755,8 @@ pub extern "C" fn popen(_command: *const c_char, _mode: *const c_char) -> *mut F
/// Put a character `c` into `stream`
#[no_mangle]
pub extern "C" fn putc(c: c_int, stream: &mut FILE) -> c_int {
- flockfile(stream);
- let ret = putc_unlocked(c, stream);
- funlockfile(stream);
- ret
+ let mut stream = stream.lock();
+ putc_unlocked(c, &mut stream)
}
/// Put a character `c` into `stdout`
@@ -849,9 +834,8 @@ pub extern "C" fn rename(oldpath: *const c_char, newpath: *const c_char) -> c_in
#[no_mangle]
pub extern "C" fn rewind(stream: &mut FILE) {
fseeko(stream, 0, SEEK_SET);
- flockfile(stream);
+ let mut stream = stream.lock();
stream.flags &= !F_ERR;
- funlockfile(stream);
}
/// Reset `stream` to use buffer `buf`. Buffer must be `BUFSIZ` in length
@@ -935,22 +919,20 @@ pub extern "C" fn ungetc(c: c_int, stream: &mut FILE) -> c_int {
if c < 0 {
c
} else {
- flockfile(stream);
+ let mut stream = stream.lock();
+
if stream.read.is_none() {
stream.can_read();
}
if let Some((rpos, rend)) = stream.read {
if rpos == 0 {
- funlockfile(stream);
return -1;
}
stream.read = Some((rpos - 1, rend));
stream.buf[rpos - 1] = c as u8;
stream.flags &= !F_EOF;
- funlockfile(stream);
c
} else {
- funlockfile(stream);
-1
}
}
--
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