diff --git a/library/std/src/sys/common/mod.rs b/library/std/src/sys/common/mod.rs
index ff64d2aa82515..29fc0835d7666 100644
--- a/library/std/src/sys/common/mod.rs
+++ b/library/std/src/sys/common/mod.rs
@@ -11,3 +11,7 @@
#![allow(dead_code)]
pub mod alloc;
+pub mod small_c_string;
+
+#[cfg(test)]
+mod tests;
diff --git a/library/std/src/sys/common/small_c_string.rs b/library/std/src/sys/common/small_c_string.rs
new file mode 100644
index 0000000000000..01acd5191351c
--- /dev/null
+++ b/library/std/src/sys/common/small_c_string.rs
@@ -0,0 +1,58 @@
+use crate::ffi::{CStr, CString};
+use crate::mem::MaybeUninit;
+use crate::path::Path;
+use crate::slice;
+use crate::{io, ptr};
+
+// Make sure to stay under 4096 so the compiler doesn't insert a probe frame:
+// https://docs.rs/compiler_builtins/latest/compiler_builtins/probestack/index.html
+#[cfg(not(target_os = "espidf"))]
+const MAX_STACK_ALLOCATION: usize = 384;
+#[cfg(target_os = "espidf")]
+const MAX_STACK_ALLOCATION: usize = 32;
+
+const NUL_ERR: io::Error =
+ io::const_io_error!(io::ErrorKind::InvalidInput, "file name contained an unexpected NUL byte");
+
+#[inline]
+pub fn run_path_with_cstr<T, F>(path: &Path, f: F) -> io::Result<T>
+where
+ F: FnOnce(&CStr) -> io::Result<T>,
+{
+ run_with_cstr(path.as_os_str().bytes(), f)
+}
+
+#[inline]
+pub fn run_with_cstr<T, F>(bytes: &[u8], f: F) -> io::Result<T>
+where
+ F: FnOnce(&CStr) -> io::Result<T>,
+{
+ if bytes.len() >= MAX_STACK_ALLOCATION {
+ return run_with_cstr_allocating(bytes, f);
+ }
+
+ let mut buf = MaybeUninit::<[u8; MAX_STACK_ALLOCATION]>::uninit();
+ let buf_ptr = buf.as_mut_ptr() as *mut u8;
+
+ unsafe {
+ ptr::copy_nonoverlapping(bytes.as_ptr(), buf_ptr, bytes.len());
+ buf_ptr.add(bytes.len()).write(0);
+ }
+
+ match CStr::from_bytes_with_nul(unsafe { slice::from_raw_parts(buf_ptr, bytes.len() + 1) }) {
+ Ok(s) => f(s),
+ Err(_) => Err(NUL_ERR),
+ }
+}
+
+#[cold]
+#[inline(never)]
+fn run_with_cstr_allocating<T, F>(bytes: &[u8], f: F) -> io::Result<T>
+where
+ F: FnOnce(&CStr) -> io::Result<T>,
+{
+ match CString::new(bytes) {
+ Ok(s) => f(&s),
+ Err(_) => Err(NUL_ERR),
+ }
+}
diff --git a/library/std/src/sys/common/tests.rs b/library/std/src/sys/common/tests.rs
new file mode 100644
index 0000000000000..fb6f5d6af8371
--- /dev/null
+++ b/library/std/src/sys/common/tests.rs
@@ -0,0 +1,66 @@
+use crate::ffi::CString;
+use crate::hint::black_box;
+use crate::path::Path;
+use crate::sys::common::small_c_string::run_path_with_cstr;
+use core::iter::repeat;
+
+#[test]
+fn stack_allocation_works() {
+ let path = Path::new("abc");
+ let result = run_path_with_cstr(path, |p| {
+ assert_eq!(p, &*CString::new(path.as_os_str().bytes()).unwrap());
+ Ok(42)
+ });
+ assert_eq!(result.unwrap(), 42);
+}
+
+#[test]
+fn stack_allocation_fails() {
+ let path = Path::new("ab\0");
+ assert!(run_path_with_cstr::<(), _>(path, |_| unreachable!()).is_err());
+}
+
+#[test]
+fn heap_allocation_works() {
+ let path = repeat("a").take(384).collect::<String>();
+ let path = Path::new(&path);
+ let result = run_path_with_cstr(path, |p| {
+ assert_eq!(p, &*CString::new(path.as_os_str().bytes()).unwrap());
+ Ok(42)
+ });
+ assert_eq!(result.unwrap(), 42);
+}
+
+#[test]
+fn heap_allocation_fails() {
+ let mut path = repeat("a").take(384).collect::<String>();
+ path.push('\0');
+ let path = Path::new(&path);
+ assert!(run_path_with_cstr::<(), _>(path, |_| unreachable!()).is_err());
+}
+
+#[bench]
+fn bench_stack_path_alloc(b: &mut test::Bencher) {
+ let path = repeat("a").take(383).collect::<String>();
+ let p = Path::new(&path);
+ b.iter(|| {
+ run_path_with_cstr(p, |cstr| {
+ black_box(cstr);
+ Ok(())
+ })
+ .unwrap();
+ });
+}
+
+#[bench]
+fn bench_heap_path_alloc(b: &mut test::Bencher) {
+ let path = repeat("a").take(384).collect::<String>();
+ let p = Path::new(&path);
+ b.iter(|| {
+ run_path_with_cstr(p, |cstr| {
+ black_box(cstr);
+ Ok(())
+ })
+ .unwrap();
+ });
+}
diff --git a/library/std/src/sys/hermit/fs.rs b/library/std/src/sys/hermit/fs.rs
index f921839cf529f..af297ff1ec75b 100644
--- a/library/std/src/sys/hermit/fs.rs
+++ b/library/std/src/sys/hermit/fs.rs
@@ -1,3 +1,4 @@
+use crate::convert::TryFrom;
use crate::ffi::{CStr, CString, OsString};
use crate::fmt;
use crate::hash::{Hash, Hasher};
@@ -5,6 +6,7 @@ use crate::io::{self, Error, ErrorKind};
use crate::io::{BorrowedCursor, IoSlice, IoSliceMut, SeekFrom};
use crate::os::unix::ffi::OsStrExt;
use crate::path::{Path, PathBuf};
+use crate::sys::common::small_c_string::run_path_with_cstr;
use crate::sys::cvt;
use crate::sys::hermit::abi;
use crate::sys::hermit::abi::{O_APPEND, O_CREAT, O_EXCL, O_RDONLY, O_RDWR, O_TRUNC, O_WRONLY};
@@ -15,10 +17,6 @@ use crate::sys::unsupported;
pub use crate::sys_common::fs::{copy, try_exists};
//pub use crate::sys_common::fs::remove_dir_all;
-fn cstr(path: &Path) -> io::Result<CString> {
- Ok(CString::new(path.as_os_str().as_bytes())?)
-}
-
#[derive(Debug)]
pub struct File(FileDesc);
@@ -272,8 +270,7 @@ impl OpenOptions {
impl File {
pub fn open(path: &Path, opts: &OpenOptions) -> io::Result<File> {
- let path = cstr(path)?;
- File::open_c(&path, opts)
+ run_path_with_cstr(path, |path| File::open_c(&path, opts))
}
pub fn open_c(path: &CStr, opts: &OpenOptions) -> io::Result<File> {
@@ -373,9 +370,7 @@ pub fn readdir(_p: &Path) -> io::Result<ReadDir> {
}
pub fn unlink(path: &Path) -> io::Result<()> {
- let name = cstr(path)?;
- let _ = unsafe { cvt(abi::unlink(name.as_ptr()))? };
- Ok(())
+ run_path_with_cstr(path, |path| cvt(unsafe { abi::unlink(path.as_ptr()) }).map(|_| ()))
}
pub fn rename(_old: &Path, _new: &Path) -> io::Result<()> {
diff --git a/library/std/src/sys/mod.rs b/library/std/src/sys/mod.rs
index 167c918c94cf9..c080c176a2ace 100644
--- a/library/std/src/sys/mod.rs
+++ b/library/std/src/sys/mod.rs
@@ -22,7 +22,7 @@
#![allow(missing_debug_implementations)]
-mod common;
+pub mod common;
cfg_if::cfg_if! {
if #[cfg(unix)] {
diff --git a/library/std/src/sys/solid/os.rs b/library/std/src/sys/solid/os.rs
index eecb347e599ef..4906c62689d4c 100644
--- a/library/std/src/sys/solid/os.rs
+++ b/library/std/src/sys/solid/os.rs
@@ -1,4 +1,5 @@
use super::unsupported;
+use crate::convert::TryFrom;
use crate::error::Error as StdError;
use crate::ffi::{CStr, CString, OsStr, OsString};
use crate::fmt;
@@ -9,6 +10,7 @@ use crate::os::{
};
use crate::path::{self, PathBuf};
use crate::sync::RwLock;
+use crate::sys::common::small_c_string::run_with_cstr;
use crate::vec;
use super::{error, itron, memchr};
@@ -139,35 +141,33 @@ pub fn env() -> Env {
pub fn getenv(k: &OsStr) -> Option<OsString> {
// environment variables with a nul byte can't be set, so their value is
// always None as well
- let k = CString::new(k.as_bytes()).ok()?;
- unsafe {
+ let s = run_with_cstr(k.as_bytes(), |k| {
let _guard = ENV_LOCK.read();
- let s = libc::getenv(k.as_ptr()) as *const libc::c_char;
- if s.is_null() {
- None
- } else {
- Some(OsStringExt::from_vec(CStr::from_ptr(s).to_bytes().to_vec()))
- }
+ Ok(unsafe { libc::getenv(k.as_ptr()) } as *const libc::c_char)
+ })
+ .ok()?;
+
+ if s.is_null() {
+ None
+ } else {
+ Some(OsStringExt::from_vec(unsafe { CStr::from_ptr(s) }.to_bytes().to_vec()))
}
}
pub fn setenv(k: &OsStr, v: &OsStr) -> io::Result<()> {
- let k = CString::new(k.as_bytes())?;
- let v = CString::new(v.as_bytes())?;
-
- unsafe {
- let _guard = ENV_LOCK.write();
- cvt_env(libc::setenv(k.as_ptr(), v.as_ptr(), 1)).map(drop)
- }
+ run_with_cstr(k.as_bytes(), |k| {
+ run_with_cstr(v.as_bytes(), |v| {
+ let _guard = ENV_LOCK.write();
+ cvt_env(unsafe { libc::setenv(k.as_ptr(), v.as_ptr(), 1) }).map(drop)
+ })
+ })
}
pub fn unsetenv(n: &OsStr) -> io::Result<()> {
- let nbuf = CString::new(n.as_bytes())?;
-
- unsafe {
+ run_with_cstr(n.as_bytes(), |nbuf| {
let _guard = ENV_LOCK.write();
- cvt_env(libc::unsetenv(nbuf.as_ptr())).map(drop)
- }
+ cvt_env(unsafe { libc::unsetenv(nbuf.as_ptr()) }).map(drop)
+ })
}
/// In kmclib, `setenv` and `unsetenv` don't always set `errno`, so this
diff --git a/library/std/src/sys/unix/fs.rs b/library/std/src/sys/unix/fs.rs
index 57c7bf6a28b90..fa03233c86ba8 100644
--- a/library/std/src/sys/unix/fs.rs
+++ b/library/std/src/sys/unix/fs.rs
@@ -1,6 +1,6 @@
use crate::os::unix::prelude::*;
-use crate::ffi::{CStr, CString, OsStr, OsString};
+use crate::ffi::{CStr, OsStr, OsString};
use crate::fmt;
use crate::io::{self, BorrowedCursor, Error, IoSlice, IoSliceMut, SeekFrom};
use crate::mem;
@@ -8,6 +8,7 @@ use crate::os::unix::io::{AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd};
use crate::path::{Path, PathBuf};
use crate::ptr;
use crate::sync::Arc;
+use crate::sys::common::small_c_string::run_path_with_cstr;
use crate::sys::fd::FileDesc;
use crate::sys::time::SystemTime;
use crate::sys::{cvt, cvt_r};
@@ -260,7 +261,7 @@ pub struct DirEntry {
// We need to store an owned copy of the entry name on platforms that use
// readdir() (not readdir_r()), because a) struct dirent may use a flexible
// array to store the name, b) it lives only until the next readdir() call.
- name: CString,
+ name: crate::ffi::CString,
}
// Define a minimal subset of fields we need from `dirent64`, especially since
@@ -900,8 +901,7 @@ impl OpenOptions {
impl File {
pub fn open(path: &Path, opts: &OpenOptions) -> io::Result<File> {
- let path = cstr(path)?;
- File::open_c(&path, opts)
+ run_path_with_cstr(path, |path| File::open_c(path, opts))
}
pub fn open_c(path: &CStr, opts: &OpenOptions) -> io::Result<File> {
@@ -1114,9 +1114,7 @@ impl DirBuilder {
}
pub fn mkdir(&self, p: &Path) -> io::Result<()> {
- let p = cstr(p)?;
- cvt(unsafe { libc::mkdir(p.as_ptr(), self.mode) })?;
- Ok(())
+ run_path_with_cstr(p, |p| cvt(unsafe { libc::mkdir(p.as_ptr(), self.mode) }).map(|_| ()))
}
pub fn set_mode(&mut self, mode: u32) {
@@ -1124,10 +1122,6 @@ impl DirBuilder {
}
}
-fn cstr(path: &Path) -> io::Result<CString> {
- Ok(CString::new(path.as_os_str().as_bytes())?)
-}
-
impl AsInner<FileDesc> for File {
fn as_inner(&self) -> &FileDesc {
&self.0
@@ -1273,173 +1267,170 @@ impl fmt::Debug for File {
}
}
-pub fn readdir(p: &Path) -> io::Result<ReadDir> {
- let root = p.to_path_buf();
- let p = cstr(p)?;
- unsafe {
- let ptr = libc::opendir(p.as_ptr());
- if ptr.is_null() {
- Err(Error::last_os_error())
- } else {
- let inner = InnerReadDir { dirp: Dir(ptr), root };
- Ok(ReadDir {
- inner: Arc::new(inner),
- #[cfg(not(any(
- target_os = "android",
- target_os = "linux",
- target_os = "solaris",
- target_os = "illumos",
- target_os = "fuchsia",
- target_os = "redox",
- )))]
- end_of_stream: false,
- })
- }
+pub fn readdir(path: &Path) -> io::Result<ReadDir> {
+ let ptr = run_path_with_cstr(path, |p| unsafe { Ok(libc::opendir(p.as_ptr())) })?;
+ if ptr.is_null() {
+ Err(Error::last_os_error())
+ } else {
+ let root = path.to_path_buf();
+ let inner = InnerReadDir { dirp: Dir(ptr), root };
+ Ok(ReadDir {
+ inner: Arc::new(inner),
+ #[cfg(not(any(
+ target_os = "android",
+ target_os = "linux",
+ target_os = "solaris",
+ target_os = "illumos",
+ target_os = "fuchsia",
+ target_os = "redox",
+ )))]
+ end_of_stream: false,
+ })
}
}
pub fn unlink(p: &Path) -> io::Result<()> {
- let p = cstr(p)?;
- cvt(unsafe { libc::unlink(p.as_ptr()) })?;
- Ok(())
+ run_path_with_cstr(p, |p| cvt(unsafe { libc::unlink(p.as_ptr()) }).map(|_| ()))
}
pub fn rename(old: &Path, new: &Path) -> io::Result<()> {
- let old = cstr(old)?;
- let new = cstr(new)?;
- cvt(unsafe { libc::rename(old.as_ptr(), new.as_ptr()) })?;
- Ok(())
+ run_path_with_cstr(old, |old| {
+ run_path_with_cstr(new, |new| {
+ cvt(unsafe { libc::rename(old.as_ptr(), new.as_ptr()) }).map(|_| ())
+ })
+ })
}
pub fn set_perm(p: &Path, perm: FilePermissions) -> io::Result<()> {
- let p = cstr(p)?;
- cvt_r(|| unsafe { libc::chmod(p.as_ptr(), perm.mode) })?;
- Ok(())
+ run_path_with_cstr(p, |p| cvt_r(|| unsafe { libc::chmod(p.as_ptr(), perm.mode) }).map(|_| ()))
}
pub fn rmdir(p: &Path) -> io::Result<()> {
- let p = cstr(p)?;
- cvt(unsafe { libc::rmdir(p.as_ptr()) })?;
- Ok(())
+ run_path_with_cstr(p, |p| cvt(unsafe { libc::rmdir(p.as_ptr()) }).map(|_| ()))
}
pub fn readlink(p: &Path) -> io::Result<PathBuf> {
- let c_path = cstr(p)?;
- let p = c_path.as_ptr();
+ run_path_with_cstr(p, |c_path| {
+ let p = c_path.as_ptr();
- let mut buf = Vec::with_capacity(256);
+ let mut buf = Vec::with_capacity(256);
- loop {
- let buf_read =
- cvt(unsafe { libc::readlink(p, buf.as_mut_ptr() as *mut _, buf.capacity()) })? as usize;
+ loop {
+ let buf_read =
+ cvt(unsafe { libc::readlink(p, buf.as_mut_ptr() as *mut _, buf.capacity()) })?
+ as usize;
- unsafe {
- buf.set_len(buf_read);
- }
+ unsafe {
+ buf.set_len(buf_read);
+ }
- if buf_read != buf.capacity() {
- buf.shrink_to_fit();
+ if buf_read != buf.capacity() {
+ buf.shrink_to_fit();
- return Ok(PathBuf::from(OsString::from_vec(buf)));
- }
+ return Ok(PathBuf::from(OsString::from_vec(buf)));
+ }
- // Trigger the internal buffer resizing logic of `Vec` by requiring
- // more space than the current capacity. The length is guaranteed to be
- // the same as the capacity due to the if statement above.
- buf.reserve(1);
- }
+ // Trigger the internal buffer resizing logic of `Vec` by requiring
+ // more space than the current capacity. The length is guaranteed to be
+ // the same as the capacity due to the if statement above.
+ buf.reserve(1);
+ }
+ })
}
pub fn symlink(original: &Path, link: &Path) -> io::Result<()> {
- let original = cstr(original)?;
- let link = cstr(link)?;
- cvt(unsafe { libc::symlink(original.as_ptr(), link.as_ptr()) })?;
- Ok(())
+ run_path_with_cstr(original, |original| {
+ run_path_with_cstr(link, |link| {
+ cvt(unsafe { libc::symlink(original.as_ptr(), link.as_ptr()) }).map(|_| ())
+ })
+ })
}
pub fn link(original: &Path, link: &Path) -> io::Result<()> {
- let original = cstr(original)?;
- let link = cstr(link)?;
- cfg_if::cfg_if! {
- if #[cfg(any(target_os = "vxworks", target_os = "redox", target_os = "android", target_os = "espidf", target_os = "horizon"))] {
- // VxWorks, Redox and ESP-IDF lack `linkat`, so use `link` instead. POSIX leaves
- // it implementation-defined whether `link` follows symlinks, so rely on the
- // `symlink_hard_link` test in library/std/src/fs/tests.rs to check the behavior.
- // Android has `linkat` on newer versions, but we happen to know `link`
- // always has the correct behavior, so it's here as well.
- cvt(unsafe { libc::link(original.as_ptr(), link.as_ptr()) })?;
- } else if #[cfg(target_os = "macos")] {
- // On MacOS, older versions (<=10.9) lack support for linkat while newer
- // versions have it. We want to use linkat if it is available, so we use weak!
- // to check. `linkat` is preferable to `link` because it gives us a flag to
- // specify how symlinks should be handled. We pass 0 as the flags argument,
- // meaning it shouldn't follow symlinks.
- weak!(fn linkat(c_int, *const c_char, c_int, *const c_char, c_int) -> c_int);
-
- if let Some(f) = linkat.get() {
- cvt(unsafe { f(libc::AT_FDCWD, original.as_ptr(), libc::AT_FDCWD, link.as_ptr(), 0) })?;
- } else {
- cvt(unsafe { libc::link(original.as_ptr(), link.as_ptr()) })?;
- };
- } else {
- // Where we can, use `linkat` instead of `link`; see the comment above
- // this one for details on why.
- cvt(unsafe { libc::linkat(libc::AT_FDCWD, original.as_ptr(), libc::AT_FDCWD, link.as_ptr(), 0) })?;
- }
- }
- Ok(())
+ run_path_with_cstr(original, |original| {
+ run_path_with_cstr(link, |link| {
+ cfg_if::cfg_if! {
+ if #[cfg(any(target_os = "vxworks", target_os = "redox", target_os = "android", target_os = "espidf", target_os = "horizon"))] {
+ // VxWorks, Redox and ESP-IDF lack `linkat`, so use `link` instead. POSIX leaves
+ // it implementation-defined whether `link` follows symlinks, so rely on the
+ // `symlink_hard_link` test in library/std/src/fs/tests.rs to check the behavior.
+ // Android has `linkat` on newer versions, but we happen to know `link`
+ // always has the correct behavior, so it's here as well.
+ cvt(unsafe { libc::link(original.as_ptr(), link.as_ptr()) })?;
+ } else if #[cfg(target_os = "macos")] {
+ // On MacOS, older versions (<=10.9) lack support for linkat while newer
+ // versions have it. We want to use linkat if it is available, so we use weak!
+ // to check. `linkat` is preferable to `link` because it gives us a flag to
+ // specify how symlinks should be handled. We pass 0 as the flags argument,
+ // meaning it shouldn't follow symlinks.
+ weak!(fn linkat(c_int, *const c_char, c_int, *const c_char, c_int) -> c_int);
+
+ if let Some(f) = linkat.get() {
+ cvt(unsafe { f(libc::AT_FDCWD, original.as_ptr(), libc::AT_FDCWD, link.as_ptr(), 0) })?;
+ } else {
+ cvt(unsafe { libc::link(original.as_ptr(), link.as_ptr()) })?;
+ };
+ } else {
+ // Where we can, use `linkat` instead of `link`; see the comment above
+ // this one for details on why.
+ cvt(unsafe { libc::linkat(libc::AT_FDCWD, original.as_ptr(), libc::AT_FDCWD, link.as_ptr(), 0) })?;
+ }
+ }
+ Ok(())
+ })
+ })
}
pub fn stat(p: &Path) -> io::Result<FileAttr> {
- let p = cstr(p)?;
-
- cfg_has_statx! {
- if let Some(ret) = unsafe { try_statx(
- libc::AT_FDCWD,
- p.as_ptr(),
- libc::AT_STATX_SYNC_AS_STAT,
- libc::STATX_ALL,
- ) } {
- return ret;
+ run_path_with_cstr(p, |p| {
+ cfg_has_statx! {
+ if let Some(ret) = unsafe { try_statx(
+ libc::AT_FDCWD,
+ p.as_ptr(),
+ libc::AT_STATX_SYNC_AS_STAT,
+ libc::STATX_ALL,
+ ) } {
+ return ret;
+ }
}
- }
- let mut stat: stat64 = unsafe { mem::zeroed() };
- cvt(unsafe { stat64(p.as_ptr(), &mut stat) })?;
- Ok(FileAttr::from_stat64(stat))
+ let mut stat: stat64 = unsafe { mem::zeroed() };
+ cvt(unsafe { stat64(p.as_ptr(), &mut stat) })?;
+ Ok(FileAttr::from_stat64(stat))
+ })
}
pub fn lstat(p: &Path) -> io::Result<FileAttr> {
- let p = cstr(p)?;
-
- cfg_has_statx! {
- if let Some(ret) = unsafe { try_statx(
- libc::AT_FDCWD,
- p.as_ptr(),
- libc::AT_SYMLINK_NOFOLLOW | libc::AT_STATX_SYNC_AS_STAT,
- libc::STATX_ALL,
- ) } {
- return ret;
+ run_path_with_cstr(p, |p| {
+ cfg_has_statx! {
+ if let Some(ret) = unsafe { try_statx(
+ libc::AT_FDCWD,
+ p.as_ptr(),
+ libc::AT_SYMLINK_NOFOLLOW | libc::AT_STATX_SYNC_AS_STAT,
+ libc::STATX_ALL,
+ ) } {
+ return ret;
+ }
}
- }
- let mut stat: stat64 = unsafe { mem::zeroed() };
- cvt(unsafe { lstat64(p.as_ptr(), &mut stat) })?;
- Ok(FileAttr::from_stat64(stat))
+ let mut stat: stat64 = unsafe { mem::zeroed() };
+ cvt(unsafe { lstat64(p.as_ptr(), &mut stat) })?;
+ Ok(FileAttr::from_stat64(stat))
+ })
}
pub fn canonicalize(p: &Path) -> io::Result<PathBuf> {
- let path = CString::new(p.as_os_str().as_bytes())?;
- let buf;
- unsafe {
- let r = libc::realpath(path.as_ptr(), ptr::null_mut());
- if r.is_null() {
- return Err(io::Error::last_os_error());
- }
- buf = CStr::from_ptr(r).to_bytes().to_vec();
- libc::free(r as *mut _);
+ let r = run_path_with_cstr(p, |path| unsafe {
+ Ok(libc::realpath(path.as_ptr(), ptr::null_mut()))
+ })?;
+ if r.is_null() {
+ return Err(io::Error::last_os_error());
}
- Ok(PathBuf::from(OsString::from_vec(buf)))
+ Ok(PathBuf::from(OsString::from_vec(unsafe {
+ let buf = CStr::from_ptr(r).to_bytes().to_vec();
+ libc::free(r as *mut _);
+ buf
+ })))
}
fn open_from(from: &Path) -> io::Result<(crate::fs::File, crate::fs::Metadata)> {
@@ -1589,9 +1580,9 @@ pub fn copy(from: &Path, to: &Path) -> io::Result<u64> {
// Opportunistically attempt to create a copy-on-write clone of `from`
// using `fclonefileat`.
if HAS_FCLONEFILEAT.load(Ordering::Relaxed) {
- let to = cstr(to)?;
- let clonefile_result =
- cvt(unsafe { fclonefileat(reader.as_raw_fd(), libc::AT_FDCWD, to.as_ptr(), 0) });
+ let clonefile_result = run_path_with_cstr(to, |to| {
+ cvt(unsafe { fclonefileat(reader.as_raw_fd(), libc::AT_FDCWD, to.as_ptr(), 0) })
+ });
match clonefile_result {
Ok(_) => return Ok(reader_metadata.len()),
Err(err) => match err.raw_os_error() {
@@ -1635,9 +1626,10 @@ pub fn copy(from: &Path, to: &Path) -> io::Result<u64> {
}
pub fn chown(path: &Path, uid: u32, gid: u32) -> io::Result<()> {
- let path = cstr(path)?;
- cvt(unsafe { libc::chown(path.as_ptr(), uid as libc::uid_t, gid as libc::gid_t) })?;
- Ok(())
+ run_path_with_cstr(path, |path| {
+ cvt(unsafe { libc::chown(path.as_ptr(), uid as libc::uid_t, gid as libc::gid_t) })
+ .map(|_| ())
+ })
}
pub fn fchown(fd: c_int, uid: u32, gid: u32) -> io::Result<()> {
@@ -1646,16 +1638,15 @@ pub fn fchown(fd: c_int, uid: u32, gid: u32) -> io::Result<()> {
}
pub fn lchown(path: &Path, uid: u32, gid: u32) -> io::Result<()> {
- let path = cstr(path)?;
- cvt(unsafe { libc::lchown(path.as_ptr(), uid as libc::uid_t, gid as libc::gid_t) })?;
- Ok(())
+ run_path_with_cstr(path, |path| {
+ cvt(unsafe { libc::lchown(path.as_ptr(), uid as libc::uid_t, gid as libc::gid_t) })
+ .map(|_| ())
+ })
}
#[cfg(not(any(target_os = "fuchsia", target_os = "vxworks")))]
pub fn chroot(dir: &Path) -> io::Result<()> {
- let dir = cstr(dir)?;
- cvt(unsafe { libc::chroot(dir.as_ptr()) })?;
- Ok(())
+ run_path_with_cstr(dir, |dir| cvt(unsafe { libc::chroot(dir.as_ptr()) }).map(|_| ()))
}
pub use remove_dir_impl::remove_dir_all;
@@ -1669,13 +1660,14 @@ mod remove_dir_impl {
// Modern implementation using openat(), unlinkat() and fdopendir()
#[cfg(not(any(target_os = "redox", target_os = "espidf", target_os = "horizon", miri)))]
mod remove_dir_impl {
- use super::{cstr, lstat, Dir, DirEntry, InnerReadDir, ReadDir};
+ use super::{lstat, Dir, DirEntry, InnerReadDir, ReadDir};
use crate::ffi::CStr;
use crate::io;
use crate::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd};
use crate::os::unix::prelude::{OwnedFd, RawFd};
use crate::path::{Path, PathBuf};
use crate::sync::Arc;
+ use crate::sys::common::small_c_string::run_path_with_cstr;
use crate::sys::{cvt, cvt_r};
#[cfg(not(all(target_os = "macos", not(target_arch = "aarch64")),))]
@@ -1842,7 +1834,7 @@ mod remove_dir_impl {
if attr.file_type().is_symlink() {
crate::fs::remove_file(p)
} else {
- remove_dir_all_recursive(None, &cstr(p)?)
+ run_path_with_cstr(p, |p| remove_dir_all_recursive(None, &p))
}
}
diff --git a/library/std/src/sys/unix/os.rs b/library/std/src/sys/unix/os.rs
index 7c70ddbd9b98b..2f2663db60769 100644
--- a/library/std/src/sys/unix/os.rs
+++ b/library/std/src/sys/unix/os.rs
@@ -7,6 +7,7 @@ mod tests;
use crate::os::unix::prelude::*;
+use crate::convert::TryFrom;
use crate::error::Error as StdError;
use crate::ffi::{CStr, CString, OsStr, OsString};
use crate::fmt;
@@ -18,6 +19,7 @@ use crate::ptr;
use crate::slice;
use crate::str;
use crate::sync::{PoisonError, RwLock};
+use crate::sys::common::small_c_string::{run_path_with_cstr, run_with_cstr};
use crate::sys::cvt;
use crate::sys::fd;
use crate::sys::memchr;
@@ -170,12 +172,8 @@ pub fn chdir(p: &path::Path) -> io::Result<()> {
#[cfg(not(target_os = "espidf"))]
pub fn chdir(p: &path::Path) -> io::Result<()> {
- let p: &OsStr = p.as_ref();
- let p = CString::new(p.as_bytes())?;
- if unsafe { libc::chdir(p.as_ptr()) } != 0 {
- return Err(io::Error::last_os_error());
- }
- Ok(())
+ let result = run_path_with_cstr(p, |p| unsafe { Ok(libc::chdir(p.as_ptr())) })?;
+ if result == 0 { Ok(()) } else { Err(io::Error::last_os_error()) }
}
pub struct SplitPaths<'a> {
@@ -548,35 +546,32 @@ pub fn env() -> Env {
pub fn getenv(k: &OsStr) -> Option<OsString> {
// environment variables with a nul byte can't be set, so their value is
// always None as well
- let k = CString::new(k.as_bytes()).ok()?;
- unsafe {
+ let s = run_with_cstr(k.as_bytes(), |k| {
let _guard = env_read_lock();
- let s = libc::getenv(k.as_ptr()) as *const libc::c_char;
- if s.is_null() {
- None
- } else {
- Some(OsStringExt::from_vec(CStr::from_ptr(s).to_bytes().to_vec()))
- }
+ Ok(unsafe { libc::getenv(k.as_ptr()) } as *const libc::c_char)
+ })
+ .ok()?;
+ if s.is_null() {
+ None
+ } else {
+ Some(OsStringExt::from_vec(unsafe { CStr::from_ptr(s) }.to_bytes().to_vec()))
}
}
pub fn setenv(k: &OsStr, v: &OsStr) -> io::Result<()> {
- let k = CString::new(k.as_bytes())?;
- let v = CString::new(v.as_bytes())?;
-
- unsafe {
- let _guard = ENV_LOCK.write();
- cvt(libc::setenv(k.as_ptr(), v.as_ptr(), 1)).map(drop)
- }
+ run_with_cstr(k.as_bytes(), |k| {
+ run_with_cstr(v.as_bytes(), |v| {
+ let _guard = ENV_LOCK.write();
+ cvt(unsafe { libc::setenv(k.as_ptr(), v.as_ptr(), 1) }).map(drop)
+ })
+ })
}
pub fn unsetenv(n: &OsStr) -> io::Result<()> {
- let nbuf = CString::new(n.as_bytes())?;
-
- unsafe {
+ run_with_cstr(n.as_bytes(), |nbuf| {
let _guard = ENV_LOCK.write();
- cvt(libc::unsetenv(nbuf.as_ptr())).map(drop)
- }
+ cvt(unsafe { libc::unsetenv(nbuf.as_ptr()) }).map(drop)
+ })
}
#[cfg(not(target_os = "espidf"))]
diff --git a/library/std/src/sys/unix/thread.rs b/library/std/src/sys/unix/thread.rs
index 56bb71b5dcbde..7df4add8ce112 100644
--- a/library/std/src/sys/unix/thread.rs
+++ b/library/std/src/sys/unix/thread.rs
@@ -154,9 +154,8 @@ impl Thread {
#[cfg(target_os = "netbsd")]
pub fn set_name(name: &CStr) {
- use crate::ffi::CString;
- let cname = CString::new(&b"%s"[..]).unwrap();
unsafe {
+ let cname = CStr::from_bytes_with_nul_unchecked(b"%s\0".as_slice());
libc::pthread_setname_np(
libc::pthread_self(),
cname.as_ptr(),
diff --git a/library/std/src/sys/wasi/fs.rs b/library/std/src/sys/wasi/fs.rs
index 953fbeb8395ef..d4866bbc32bad 100644
--- a/library/std/src/sys/wasi/fs.rs
+++ b/library/std/src/sys/wasi/fs.rs
@@ -1,7 +1,7 @@
#![deny(unsafe_op_in_unsafe_fn)]
use super::fd::WasiFd;
-use crate::ffi::{CStr, CString, OsStr, OsString};
+use crate::ffi::{CStr, OsStr, OsString};
use crate::fmt;
use crate::io::{self, BorrowedCursor, IoSlice, IoSliceMut, SeekFrom};
use crate::iter;
@@ -12,6 +12,7 @@ use crate::os::wasi::io::{AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, RawFd
use crate::path::{Path, PathBuf};
use crate::ptr;
use crate::sync::Arc;
+use crate::sys::common::small_c_string::run_path_with_cstr;
use crate::sys::time::SystemTime;
use crate::sys::unsupported;
use crate::sys_common::{AsInner, FromInner, IntoInner};
@@ -694,51 +695,52 @@ fn open_at(fd: &WasiFd, path: &Path, opts: &OpenOptions) -> io::Result<File> {
/// Note that this can fail if `p` doesn't look like it can be opened relative
/// to any pre-opened file descriptor.
fn open_parent(p: &Path) -> io::Result<(ManuallyDrop<WasiFd>, PathBuf)> {
- let p = CString::new(p.as_os_str().as_bytes())?;
- let mut buf = Vec::<u8>::with_capacity(512);
- loop {
- unsafe {
- let mut relative_path = buf.as_ptr().cast();
- let mut abs_prefix = ptr::null();
- let fd = __wasilibc_find_relpath(
- p.as_ptr(),
- &mut abs_prefix,
- &mut relative_path,
- buf.capacity(),
- );
- if fd == -1 {
- if io::Error::last_os_error().raw_os_error() == Some(libc::ENOMEM) {
- // Trigger the internal buffer resizing logic of `Vec` by requiring
- // more space than the current capacity.
- let cap = buf.capacity();
- buf.set_len(cap);
- buf.reserve(1);
- continue;
- }
- let msg = format!(
- "failed to find a pre-opened file descriptor \
- through which {:?} could be opened",
- p
+ run_path_with_cstr(p, |p| {
+ let mut buf = Vec::<u8>::with_capacity(512);
+ loop {
+ unsafe {
+ let mut relative_path = buf.as_ptr().cast();
+ let mut abs_prefix = ptr::null();
+ let fd = __wasilibc_find_relpath(
+ p.as_ptr(),
+ &mut abs_prefix,
+ &mut relative_path,
+ buf.capacity(),
);
- return Err(io::Error::new(io::ErrorKind::Uncategorized, msg));
- }
- let relative = CStr::from_ptr(relative_path).to_bytes().to_vec();
+ if fd == -1 {
+ if io::Error::last_os_error().raw_os_error() == Some(libc::ENOMEM) {
+ // Trigger the internal buffer resizing logic of `Vec` by requiring
+ // more space than the current capacity.
+ let cap = buf.capacity();
+ buf.set_len(cap);
+ buf.reserve(1);
+ continue;
+ }
+ let msg = format!(
+ "failed to find a pre-opened file descriptor \
+ through which {:?} could be opened",
+ p
+ );
+ return Err(io::Error::new(io::ErrorKind::Uncategorized, msg));
+ }
+ let relative = CStr::from_ptr(relative_path).to_bytes().to_vec();
- return Ok((
- ManuallyDrop::new(WasiFd::from_raw_fd(fd as c_int)),
- PathBuf::from(OsString::from_vec(relative)),
- ));
+ return Ok((
+ ManuallyDrop::new(WasiFd::from_raw_fd(fd as c_int)),
+ PathBuf::from(OsString::from_vec(relative)),
+ ));
+ }
}
- }
- extern "C" {
- pub fn __wasilibc_find_relpath(
- path: *const libc::c_char,
- abs_prefix: *mut *const libc::c_char,
- relative_path: *mut *const libc::c_char,
- relative_path_len: libc::size_t,
- ) -> libc::c_int;
- }
+ extern "C" {
+ pub fn __wasilibc_find_relpath(
+ path: *const libc::c_char,
+ abs_prefix: *mut *const libc::c_char,
+ relative_path: *mut *const libc::c_char,
+ relative_path_len: libc::size_t,
+ ) -> libc::c_int;
+ }
+ })
}
pub fn osstr2str(f: &OsStr) -> io::Result<&str> {
diff --git a/library/std/src/sys/wasi/os.rs b/library/std/src/sys/wasi/os.rs
index c5229a188342a..cab2887dfcf14 100644
--- a/library/std/src/sys/wasi/os.rs
+++ b/library/std/src/sys/wasi/os.rs
@@ -2,13 +2,14 @@
use crate::any::Any;
use crate::error::Error as StdError;
-use crate::ffi::{CStr, CString, OsStr, OsString};
+use crate::ffi::{CStr, OsStr, OsString};
use crate::fmt;
use crate::io;
use crate::marker::PhantomData;
use crate::os::wasi::prelude::*;
use crate::path::{self, PathBuf};
use crate::str;
+use crate::sys::common::small_c_string::{run_path_with_cstr, run_with_cstr};
use crate::sys::memchr;
use crate::sys::unsupported;
use crate::vec;
@@ -77,13 +78,10 @@ pub fn getcwd() -> io::Result<PathBuf> {
}
pub fn chdir(p: &path::Path) -> io::Result<()> {
- let p: &OsStr = p.as_ref();
- let p = CString::new(p.as_bytes())?;
- unsafe {
- match libc::chdir(p.as_ptr()) == (0 as libc::c_int) {
- true => Ok(()),
- false => Err(io::Error::last_os_error()),
- }
+ let result = run_path_with_cstr(p, |p| unsafe { Ok(libc::chdir(p.as_ptr())) })?;
+ match result == (0 as libc::c_int) {
+ true => Ok(()),
+ false => Err(io::Error::last_os_error()),
}
}
@@ -176,35 +174,32 @@ pub fn env() -> Env {
}
pub fn getenv(k: &OsStr) -> Option<OsString> {
- let k = CString::new(k.as_bytes()).ok()?;
- unsafe {
+ let s = run_with_cstr(k.as_bytes(), |k| unsafe {
let _guard = env_lock();
- let s = libc::getenv(k.as_ptr()) as *const libc::c_char;
- if s.is_null() {
- None
- } else {
- Some(OsStringExt::from_vec(CStr::from_ptr(s).to_bytes().to_vec()))
- }
+ Ok(libc::getenv(k.as_ptr()) as *const libc::c_char)
+ })
+ .ok()?;
+ if s.is_null() {
+ None
+ } else {
+ Some(OsStringExt::from_vec(unsafe { CStr::from_ptr(s) }.to_bytes().to_vec()))
}
}
pub fn setenv(k: &OsStr, v: &OsStr) -> io::Result<()> {
- let k = CString::new(k.as_bytes())?;
- let v = CString::new(v.as_bytes())?;
-
- unsafe {
- let _guard = env_lock();
- cvt(libc::setenv(k.as_ptr(), v.as_ptr(), 1)).map(drop)
- }
+ run_with_cstr(k.as_bytes(), |k| {
+ run_with_cstr(v.as_bytes(), |v| unsafe {
+ let _guard = env_lock();
+ cvt(libc::setenv(k.as_ptr(), v.as_ptr(), 1)).map(drop)
+ })
+ })
}
pub fn unsetenv(n: &OsStr) -> io::Result<()> {
- let nbuf = CString::new(n.as_bytes())?;
-
- unsafe {
+ run_with_cstr(n.as_bytes(), |nbuf| unsafe {
let _guard = env_lock();
cvt(libc::unsetenv(nbuf.as_ptr())).map(drop)
- }
+ })
}
pub fn temp_dir() -> PathBuf {
diff --git a/library/std/src/sys_common/net.rs b/library/std/src/sys_common/net.rs
index 3ad802afa8f7a..fad4a63331b59 100644
--- a/library/std/src/sys_common/net.rs
+++ b/library/std/src/sys_common/net.rs
@@ -2,12 +2,13 @@
mod tests;
use crate::cmp;
-use crate::ffi::CString;
+use crate::convert::{TryFrom, TryInto};
use crate::fmt;
use crate::io::{self, ErrorKind, IoSlice, IoSliceMut};
use crate::mem;
use crate::net::{Ipv4Addr, Ipv6Addr, Shutdown, SocketAddr};
use crate::ptr;
+use crate::sys::common::small_c_string::run_with_cstr;
use crate::sys::net::netc as c;
use crate::sys::net::{cvt, cvt_gai, cvt_r, init, wrlen_t, Socket};
use crate::sys_common::{AsInner, FromInner, IntoInner};
@@ -197,14 +198,15 @@ impl<'a> TryFrom<(&'a str, u16)> for LookupHost {
fn try_from((host, port): (&'a str, u16)) -> io::Result<LookupHost> {
init();
- let c_host = CString::new(host)?;
- let mut hints: c::addrinfo = unsafe { mem::zeroed() };
- hints.ai_socktype = c::SOCK_STREAM;
- let mut res = ptr::null_mut();
- unsafe {
- cvt_gai(c::getaddrinfo(c_host.as_ptr(), ptr::null(), &hints, &mut res))
- .map(|_| LookupHost { original: res, cur: res, port })
- }
+ run_with_cstr(host.as_bytes(), |c_host| {
+ let mut hints: c::addrinfo = unsafe { mem::zeroed() };
+ hints.ai_socktype = c::SOCK_STREAM;
+ let mut res = ptr::null_mut();
+ unsafe {
+ cvt_gai(c::getaddrinfo(c_host.as_ptr(), ptr::null(), &hints, &mut res))
+ .map(|_| LookupHost { original: res, cur: res, port })
+ }
+ })
}
}
diff --git a/src/tools/miri/tests/fail/shims/fs/isolated_file.stderr b/src/tools/miri/tests/fail/shims/fs/isolated_file.stderr
index 4e3fdc7a45801..269b1383aad68 100644
--- a/src/tools/miri/tests/fail/shims/fs/isolated_file.stderr
+++ b/src/tools/miri/tests/fail/shims/fs/isolated_file.stderr
@@ -10,6 +10,9 @@ LL | let fd = cvt_r(|| unsafe { open64(path.as_ptr(), flags, opts.mode a
= note: inside closure at RUSTLIB/std/src/sys/PLATFORM/fs.rs:LL:CC
= note: inside `std::sys::PLATFORM::cvt_r::<i32, [closure@std::sys::PLATFORM::fs::File::open_c::{closure#0}]>` at RUSTLIB/std/src/sys/PLATFORM/mod.rs:LL:CC
= note: inside `std::sys::PLATFORM::fs::File::open_c` at RUSTLIB/std/src/sys/PLATFORM/fs.rs:LL:CC
+ = note: inside closure at RUSTLIB/std/src/sys/PLATFORM/fs.rs:LL:CC
+ = note: inside `std::sys::PLATFORM::small_c_string::run_with_cstr::<std::sys::PLATFORM::fs::File, [closure@std::sys::PLATFORM::fs::File::open::{closure#0}]>` at RUSTLIB/std/src/sys/PLATFORM/small_c_string.rs:LL:CC
+ = note: inside `std::sys::PLATFORM::small_c_string::run_path_with_cstr::<std::sys::PLATFORM::fs::File, [closure@std::sys::PLATFORM::fs::File::open::{closure#0}]>` at RUSTLIB/std/src/sys/PLATFORM/small_c_string.rs:LL:CC
= note: inside `std::sys::PLATFORM::fs::File::open` at RUSTLIB/std/src/sys/PLATFORM/fs.rs:LL:CC
= note: inside `std::fs::OpenOptions::_open` at RUSTLIB/std/src/fs.rs:LL:CC
= note: inside `std::fs::OpenOptions::open::<&std::path::Path>` at RUSTLIB/std/src/fs.rs:LL:CC