From 36775eeb1bc916f490c76e1f7cfbbbb3b3adb097 Mon Sep 17 00:00:00 2001
From: 4lDO2 <4lDO2@protonmail.com>
Date: Fri, 12 Aug 2022 13:00:12 +0200
Subject: [PATCH] Implement EXDEV symlink resolution.
---
src/platform/redox/mod.rs | 21 ++++++++++++++-------
src/platform/redox/path.rs | 35 ++++++++++++++++++++++++++++++++---
2 files changed, 46 insertions(+), 10 deletions(-)
diff --git a/src/platform/redox/mod.rs b/src/platform/redox/mod.rs
index 8f528a280..8b7484946 100644
--- a/src/platform/redox/mod.rs
+++ b/src/platform/redox/mod.rs
@@ -1,10 +1,11 @@
use core::{mem, ptr, result::Result as CoreResult, slice, str};
+use core::convert::TryFrom;
use core::arch::asm;
use syscall::{
self,
data::{Map, Stat as redox_stat, StatVfs as redox_statvfs, TimeSpec as redox_timespec},
- PtraceEvent, Result,
+ PtraceEvent, Result, Error, EMFILE,
};
use crate::{
@@ -705,12 +706,18 @@ impl Pal for Sys {
fn open(path: &CStr, oflag: c_int, mode: mode_t) -> c_int {
let path = path_from_c_str!(path);
- e(canonicalize(path).and_then(|canon| {
- syscall::open(
- &canon,
- ((oflag as usize) & 0xFFFF_0000) | ((mode as usize) & 0xFFFF),
- )
- })) as c_int
+ match path::open(path, ((oflag as usize) & 0xFFFF_0000) | ((mode as usize) & 0xFFFF)) {
+ Ok(fd) => {
+ match c_int::try_from(fd) {
+ Ok(c_fd) => c_fd,
+ Err(_) => {
+ let _ = syscall::close(fd);
+ e(Err(Error::new(EMFILE))) as c_int
+ }
+ }
+ }
+ Err(error) => e(Err(error)) as c_int,
+ }
}
fn pipe2(fds: &mut [c_int], flags: c_int) -> c_int {
diff --git a/src/platform/redox/path.rs b/src/platform/redox/path.rs
index 75e3f8c94..45e3e7bba 100644
--- a/src/platform/redox/path.rs
+++ b/src/platform/redox/path.rs
@@ -1,11 +1,12 @@
use syscall::error::*;
use syscall::flag::*;
-use alloc::borrow::ToOwned;
+use alloc::borrow::{Cow, ToOwned};
use alloc::boxed::Box;
use alloc::string::String;
use alloc::vec::Vec;
+use super::FdGuard;
use crate::sync::Mutex;
// TODO: Define in syscall
@@ -16,7 +17,7 @@ const PATH_MAX: usize = 4096;
/// Given a cwd of "scheme:/path", this his function will turn "foo" into "scheme:/path/foo".
/// "/foo" will turn into "scheme:/foo". "bar:/foo" will be used directly, as it is already
/// absolute
-pub fn canonicalize_using_cwd(cwd_opt: Option<&str>, path: &str) -> Option<String> {
+pub fn canonicalize_using_cwd<'a>(cwd_opt: Option<&str>, path: &'a str) -> Option<String> {
let mut canon = if path.find(':').is_none() {
let cwd = cwd_opt?;
let path_start = cwd.find(':')? + 1;
@@ -99,7 +100,6 @@ pub fn chdir(path: &str) -> Result<()> {
// TODO: Check that the dir exists and is a directory.
Ok(())
-
}
pub fn clone_cwd() -> Option<Box<str>> {
@@ -154,3 +154,32 @@ impl Drop for SignalMask {
let _ = syscall::sigprocmask(syscall::SIG_SETMASK, Some(&self.oldset), None);
}
}
+
+pub fn open(path: &str, flags: usize) -> Result<usize> {
+ // TODO: SYMLOOP_MAX
+ const MAX_LEVEL: usize = 64;
+
+ let mut resolve_buf = [0_u8; 4096];
+ let mut path = path;
+
+ for _ in 0..MAX_LEVEL {
+ let canon = canonicalize(path)?;
+ match syscall::open(&*canon, flags) {
+ Ok(fd) => return Ok(fd),
+ Err(error) if error == Error::new(EXDEV) => {
+ let resolve_flags = O_CLOEXEC | O_SYMLINK | O_RDONLY;
+ let resolve_fd = FdGuard::new(syscall::open(&*canon, resolve_flags)?);
+
+ let bytes_read = syscall::read(*resolve_fd, &mut resolve_buf)?;
+ // TODO: make resolve_buf PATH_MAX + 1 bytes?
+ if bytes_read == resolve_buf.len() { return Err(Error::new(ENAMETOOLONG)); }
+
+ // If the symbolic link path is non-UTF8, it cannot be opened, and is thus
+ // considered a "dangling symbolic link".
+ path = core::str::from_utf8(&resolve_buf[..bytes_read]).map_err(|_| Error::new(ENOENT))?;
+ }
+ Err(other_error) => return Err(other_error),
+ }
+ }
+ Err(Error::new(ELOOP))
+}
--
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