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add statx shim for linux

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Christian Poveda 2019-11-30 15:09:52 -05:00 • committed by Christian Poveda
parent 878bb4d78f
commit b0c7625dd1
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GPG key ID: 27525EF5E7420A50
6 changed files with 303 additions and 37 deletions
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42
src/helpers.rs
View file

@ -509,3 +509,45 @@ fn bytes_to_os_str<'tcx, 'a>(bytes: &'a [u8]) -> InterpResult<'tcx, &'a OsStr> {
.map_err(|_| err_unsup_format!("{:?} is not a valid utf-8 string", bytes))?;
Ok(&OsStr::new(s))
}
// FIXME: change `ImmTy::from_int` so it returns an `InterpResult` instead and remove this
// function.
pub fn immty_from_int_checked<'tcx>(
int: impl Into<i128>,
layout: TyLayout<'tcx>,
) -> InterpResult<'tcx, ImmTy<'tcx, Tag>> {
let int = int.into();
// If `int` does not fit in `size` bits, we error instead of letting
// `ImmTy::from_int` panic.
let size = layout.size;
let truncated = truncate(int as u128, size);
if sign_extend(truncated, size) as i128 != int {
throw_unsup_format!(
"Signed value {:#x} does not fit in {} bits",
int,
size.bits()
)
}
Ok(ImmTy::from_int(int, layout))
}
// FIXME: change `ImmTy::from_uint` so it returns an `InterpResult` instead and remove this
// function.
pub fn immty_from_uint_checked<'tcx>(
int: impl Into<u128>,
layout: TyLayout<'tcx>,
) -> InterpResult<'tcx, ImmTy<'tcx, Tag>> {
let int = int.into();
// If `int` does not fit in `size` bits, we error instead of letting
// `ImmTy::from_int` panic.
let size = layout.size;
if truncate(int, size) != int {
throw_unsup_format!(
"Unsigned value {:#x} does not fit in {} bits",
int,
size.bits()
)
}
Ok(ImmTy::from_uint(int, layout))
}

8
src/shims/env.rs
View file

@ -20,8 +20,12 @@ impl EnvVars {
ecx: &mut InterpCx<'mir, 'tcx, Evaluator<'tcx>>,
mut excluded_env_vars: Vec<String>,
) {
// Exclude `TERM` var to avoid terminfo trying to open the termcap file.
excluded_env_vars.push("TERM".to_owned());
// FIXME: this can be removed when we have the `stat64` shim for macos.
if ecx.tcx.sess.target.target.target_os.to_lowercase() != "linux" {
// Exclude `TERM` var to avoid terminfo trying to open the termcap file.
excluded_env_vars.push("TERM".to_owned());
}
if ecx.machine.communicate {
for (name, value) in env::vars() {

15
src/shims/foreign_items.rs
View file

@ -303,14 +303,25 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
.expect("Failed to get libc::SYS_getrandom")
.to_machine_usize(this)?;
// `libc::syscall(NR_GETRANDOM, buf.as_mut_ptr(), buf.len(), GRND_NONBLOCK)`
// is called if a `HashMap` is created the regular way (e.g. HashMap<K, V>).
let sys_statx = this
.eval_path_scalar(&["libc", "SYS_statx"])?
.expect("Failed to get libc::SYS_statx")
.to_machine_usize(this)?;
match this.read_scalar(args[0])?.to_machine_usize(this)? {
// `libc::syscall(NR_GETRANDOM, buf.as_mut_ptr(), buf.len(), GRND_NONBLOCK)`
// is called if a `HashMap` is created the regular way (e.g. HashMap<K, V>).
id if id == sys_getrandom => {
// The first argument is the syscall id,
// so skip over it.
linux_getrandom(this, &args[1..], dest)?;
}
id if id == sys_statx => {
// The first argument is the syscall id,
// so skip over it.
let result = this.statx(args[1], args[2], args[3], args[4], args[5])?;
this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
}
id => throw_unsup_format!("miri does not support syscall ID {}", id),
}
}

198
src/shims/fs.rs
View file

@ -1,12 +1,16 @@
use std::collections::HashMap;
use std::convert::TryFrom;
use std::convert::{TryInto, TryFrom};
use std::fs::{remove_file, File, OpenOptions};
use std::io::{Read, Write};
use std::path::PathBuf;
use std::time::SystemTime;
use rustc::ty::layout::{Size, Align};
use rustc::ty::layout::{Size, Align, LayoutOf};
use crate::stacked_borrows::Tag;
use crate::*;
use helpers::immty_from_uint_checked;
use shims::time::system_time_to_duration;
#[derive(Debug)]
pub struct FileHandle {
@ -98,7 +102,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
let path = this.read_os_str_from_c_str(this.read_scalar(path_op)?.not_undef()?)?;
let fd = options.open(path).map(|file| {
let fd = options.open(&path).map(|file| {
let mut fh = &mut this.machine.file_handler;
fh.low += 1;
fh.handles.insert(fh.low, FileHandle { file }).unwrap_none();
@ -257,6 +261,181 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
this.try_unwrap_io_result(result)
}
fn statx(
&mut self,
dirfd_op: OpTy<'tcx, Tag>, // Should be an `int`
pathname_op: OpTy<'tcx, Tag>, // Should be a `const char *`
flags_op: OpTy<'tcx, Tag>, // Should be an `int`
_mask_op: OpTy<'tcx, Tag>, // Should be an `unsigned int`
statxbuf_op: OpTy<'tcx, Tag> // Should be a `struct statx *`
) -> InterpResult<'tcx, i32> {
let this = self.eval_context_mut();
this.check_no_isolation("statx")?;
let statxbuf_scalar = this.read_scalar(statxbuf_op)?.not_undef()?;
let pathname_scalar = this.read_scalar(pathname_op)?.not_undef()?;
// If the statxbuf or pathname pointers are null, the function fails with `EFAULT`.
if this.is_null(statxbuf_scalar)? || this.is_null(pathname_scalar)? {
let efault = this.eval_libc("EFAULT")?;
this.set_last_error(efault)?;
return Ok(-1);
}
// Under normal circumstances, we would use `deref_operand(statxbuf_op)` to produce a
// proper `MemPlace` and then write the results of this function to it. However, the
// `syscall` function is untyped. This means that all the `statx` parameters are provided
// as `isize`s instead of having the proper types. Thus, we have to recover the layout of
// `statxbuf_op` by using the `libc::statx` struct type.
let statxbuf_place = {
// FIXME: This long path is required because `libc::statx` is an struct and also a
// function and `resolve_path` is returning the latter.
let statx_ty = this
.resolve_path(&["libc", "unix", "linux_like", "linux", "gnu", "statx"])?
.ty(*this.tcx);
let statxbuf_ty = this.tcx.mk_mut_ptr(statx_ty);
let statxbuf_layout = this.layout_of(statxbuf_ty)?;
let statxbuf_imm = ImmTy::from_scalar(statxbuf_scalar, statxbuf_layout);
this.ref_to_mplace(statxbuf_imm)?
};
let path: PathBuf = this.read_os_str_from_c_str(pathname_scalar)?.into();
// `flags` should be a `c_int` but the `syscall` function provides an `isize`.
let flags: i32 = this
.read_scalar(flags_op)?
.to_machine_isize(&*this.tcx)?
.try_into()
.map_err(|e| err_unsup_format!(
"Failed to convert pointer sized operand to integer: {}",
e
))?;
// `dirfd` should be a `c_int` but the `syscall` function provides an `isize`.
let dirfd: i32 = this
.read_scalar(dirfd_op)?
.to_machine_isize(&*this.tcx)?
.try_into()
.map_err(|e| err_unsup_format!(
"Failed to convert pointer sized operand to integer: {}",
e
))?;
// we only support interpreting `path` as an absolute directory or as a directory relative
// to `dirfd` when the latter is `AT_FDCWD`. The behavior of `statx` with a relative path
// and a directory file descriptor other than `AT_FDCWD` is specified but it cannot be
// tested from `libstd`. If you found this error, please open an issue reporting it.
if !(path.is_absolute() || dirfd == this.eval_libc_i32("AT_FDCWD")?)
{
throw_unsup_format!(
"Using statx with a relative path and a file descriptor different from `AT_FDCWD` is not supported"
)
}
// the `_mask_op` paramter specifies the file information that the caller requested.
// However `statx` is allowed to return information that was not requested or to not
// return information that was requested. This `mask` represents the information we can
// actually provide in any host platform.
let mut mask =
this.eval_libc("STATX_TYPE")?.to_u32()? | this.eval_libc("STATX_SIZE")?.to_u32()?;
// If the `AT_SYMLINK_NOFOLLOW` flag is set, we query the file's metadata without following
// symbolic links.
let metadata = if flags & this.eval_libc("AT_SYMLINK_NOFOLLOW")?.to_i32()? != 0 {
// FIXME: metadata for symlinks need testing.
std::fs::symlink_metadata(path)
} else {
std::fs::metadata(path)
};
let metadata = match metadata {
Ok(metadata) => metadata,
Err(e) => {
this.set_last_error_from_io_error(e)?;
return Ok(-1);
}
};
let file_type = metadata.file_type();
let mode_name = if file_type.is_file() {
"S_IFREG"
} else if file_type.is_dir() {
"S_IFDIR"
} else {
"S_IFLNK"
};
// The `mode` field specifies the type of the file and the permissions over the file for
// the owner, its group and other users. Given that we can only provide the file type
// without using platform specific methods, we only set the bits corresponding to the file
// type. This should be an `__u16` but `libc` provides its values as `u32`.
let mode: u16 = this.eval_libc(mode_name)?
.to_u32()?
.try_into()
.unwrap_or_else(|_| bug!("libc contains bad value for `{}` constant", mode_name));
let size = metadata.len();
let (access_sec, access_nsec) = extract_sec_and_nsec(
metadata.accessed(),
&mut mask,
this.eval_libc("STATX_ATIME")?.to_u32()?
)?;
let (created_sec, created_nsec) = extract_sec_and_nsec(
metadata.created(),
&mut mask,
this.eval_libc("STATX_BTIME")?.to_u32()?
)?;
let (modified_sec, modified_nsec) = extract_sec_and_nsec(
metadata.modified(),
&mut mask,
this.eval_libc("STATX_MTIME")?.to_u32()?
)?;
let __u32_layout = this.libc_ty_layout("__u32")?;
let __u64_layout = this.libc_ty_layout("__u64")?;
let __u16_layout = this.libc_ty_layout("__u16")?;
// Now we transform all this fields into `ImmTy`s and write them to `statxbuf`. We write a
// zero for the unavailable fields.
// FIXME: Provide more fields using platform specific methods.
let imms = [
immty_from_uint_checked(mask, __u32_layout)?, // stx_mask
immty_from_uint_checked(0u128, __u32_layout)?, // stx_blksize
immty_from_uint_checked(0u128, __u64_layout)?, // stx_attributes
immty_from_uint_checked(0u128, __u32_layout)?, // stx_nlink
immty_from_uint_checked(0u128, __u32_layout)?, // stx_uid
immty_from_uint_checked(0u128, __u32_layout)?, // stx_gid
immty_from_uint_checked(mode, __u16_layout)?, // stx_mode
immty_from_uint_checked(0u128, __u16_layout)?, // statx padding
immty_from_uint_checked(0u128, __u64_layout)?, // stx_ino
immty_from_uint_checked(size, __u64_layout)?, // stx_size
immty_from_uint_checked(0u128, __u64_layout)?, // stx_blocks
immty_from_uint_checked(0u128, __u64_layout)?, // stx_attributes
immty_from_uint_checked(access_sec, __u64_layout)?, // stx_atime.tv_sec
immty_from_uint_checked(access_nsec, __u32_layout)?, // stx_atime.tv_nsec
immty_from_uint_checked(0u128, __u32_layout)?, // statx_timestamp padding
immty_from_uint_checked(created_sec, __u64_layout)?, // stx_btime.tv_sec
immty_from_uint_checked(created_nsec, __u32_layout)?, // stx_btime.tv_nsec
immty_from_uint_checked(0u128, __u32_layout)?, // statx_timestamp padding
immty_from_uint_checked(0u128, __u64_layout)?, // stx_ctime.tv_sec
immty_from_uint_checked(0u128, __u32_layout)?, // stx_ctime.tv_nsec
immty_from_uint_checked(0u128, __u32_layout)?, // statx_timestamp padding
immty_from_uint_checked(modified_sec, __u64_layout)?, // stx_mtime.tv_sec
immty_from_uint_checked(modified_nsec, __u32_layout)?, // stx_mtime.tv_nsec
immty_from_uint_checked(0u128, __u32_layout)?, // statx_timestamp padding
immty_from_uint_checked(0u128, __u64_layout)?, // stx_rdev_major
immty_from_uint_checked(0u128, __u64_layout)?, // stx_rdev_minor
immty_from_uint_checked(0u128, __u64_layout)?, // stx_dev_major
immty_from_uint_checked(0u128, __u64_layout)?, // stx_dev_minor
];
this.write_packed_immediates(&statxbuf_place, &imms)?;
Ok(0)
}
/// Function used when a handle is not found inside `FileHandler`. It returns `Ok(-1)`and sets
/// the last OS error to `libc::EBADF` (invalid file descriptor). This function uses
/// `T: From<i32>` instead of `i32` directly because some fs functions return different integer
@ -268,3 +447,16 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
Ok((-1).into())
}
}
// Extracts the number of seconds and nanoseconds elapsed between `time` and the unix epoch, and
// then sets the `mask` bits determined by `flag` when `time` is Ok. If `time` is an error, it
// returns `(0, 0)` without setting any bits.
fn extract_sec_and_nsec<'tcx>(time: std::io::Result<SystemTime>, mask: &mut u32, flag: u32) -> InterpResult<'tcx, (u64, u32)> {
if let Ok(time) = time {
let duration = system_time_to_duration(&time)?;
*mask |= flag;
Ok((duration.as_secs(), duration.subsec_nanos()))
} else {
Ok((0, 0))
}
}

39
src/shims/time.rs
View file

@ -1,34 +1,19 @@
use std::time::{Duration, SystemTime};
use rustc::ty::layout::TyLayout;
use crate::stacked_borrows::Tag;
use crate::*;
use helpers::immty_from_int_checked;
// Returns the time elapsed between now and the unix epoch as a `Duration` and the sign of the time
// interval
// Returns the time elapsed between now and the unix epoch as a `Duration`.
fn get_time<'tcx>() -> InterpResult<'tcx, Duration> {
SystemTime::now()
.duration_since(SystemTime::UNIX_EPOCH)
.map_err(|_| err_unsup_format!("Times before the Unix epoch are not supported").into())
system_time_to_duration(&SystemTime::now())
}
fn int_to_immty_checked<'tcx>(
int: i128,
layout: TyLayout<'tcx>,
) -> InterpResult<'tcx, ImmTy<'tcx, Tag>> {
// If `int` does not fit in `size` bits, we error instead of letting
// `ImmTy::from_int` panic.
let size = layout.size;
let truncated = truncate(int as u128, size);
if sign_extend(truncated, size) as i128 != int {
throw_unsup_format!(
"Signed value {:#x} does not fit in {} bits",
int,
size.bits()
)
}
Ok(ImmTy::from_int(int, layout))
// Returns the time elapsed between the provided time and the unix epoch as a `Duration`.
pub fn system_time_to_duration<'tcx>(time: &SystemTime) -> InterpResult<'tcx, Duration> {
time
.duration_since(SystemTime::UNIX_EPOCH)
.map_err(|_| err_unsup_format!("Times before the Unix epoch are not supported").into())
}
impl<'mir, 'tcx> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
@ -57,8 +42,8 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
let tv_nsec = duration.subsec_nanos() as i128;
let imms = [
int_to_immty_checked(tv_sec, this.libc_ty_layout("time_t")?)?,
int_to_immty_checked(tv_nsec, this.libc_ty_layout("c_long")?)?,
immty_from_int_checked(tv_sec, this.libc_ty_layout("time_t")?)?,
immty_from_int_checked(tv_nsec, this.libc_ty_layout("c_long")?)?,
];
this.write_packed_immediates(&tp, &imms)?;
@ -89,8 +74,8 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
let tv_usec = duration.subsec_micros() as i128;
let imms = [
int_to_immty_checked(tv_sec, this.libc_ty_layout("time_t")?)?,
int_to_immty_checked(tv_usec, this.libc_ty_layout("suseconds_t")?)?,
immty_from_int_checked(tv_sec, this.libc_ty_layout("time_t")?)?,
immty_from_int_checked(tv_usec, this.libc_ty_layout("suseconds_t")?)?,
];
this.write_packed_immediates(&tv, &imms)?;

38
tests/run-pass/fs.rs
View file

@ -2,11 +2,32 @@
// compile-flags: -Zmiri-disable-isolation
use std::fs::{File, remove_file};
use std::io::{Read, Write, ErrorKind};
use std::io::{Read, Write, ErrorKind, Result};
use std::path::{PathBuf, Path};
#[cfg(target_os = "linux")]
fn test_metadata(bytes: &[u8], path: &Path) -> Result<()> {
// Test that the file metadata is correct.
let metadata = path.metadata()?;
// `path` should point to a file.
assert!(metadata.is_file());
// The size of the file must be equal to the number of written bytes.
assert_eq!(bytes.len() as u64, metadata.len());
Ok(())
}
// FIXME: Implement stat64 for macos.
#[cfg(not(target_os = "linux"))]
fn test_metadata(_bytes: &[u8], _path: &Path) -> Result<()> {
Ok(())
}
fn main() {
let path = std::env::temp_dir().join("miri_test_fs.txt");
let tmp = std::env::temp_dir();
let filename = PathBuf::from("miri_test_fs.txt");
let path = tmp.join(&filename);
let bytes = b"Hello, World!\n";
// Test creating, writing and closing a file (closing is tested when `file` is dropped).
let mut file = File::create(&path).unwrap();
// Writing 0 bytes should not change the file contents.
@ -21,7 +42,14 @@ fn main() {
// Reading until EOF should get the whole text.
file.read_to_end(&mut contents).unwrap();
assert_eq!(bytes, contents.as_slice());
// Removing file should succeed
// Test that metadata of an absolute path is correct.
test_metadata(bytes, &path).unwrap();
// Test that metadata of a relative path is correct.
std::env::set_current_dir(tmp).unwrap();
test_metadata(bytes, &filename).unwrap();
// Removing file should succeed.
remove_file(&path).unwrap();
// The two following tests also check that the `__errno_location()` shim is working properly.
@ -29,4 +57,8 @@ fn main() {
assert_eq!(ErrorKind::NotFound, File::open(&path).unwrap_err().kind());
// Removing a non-existing file should fail with a "not found" error.
assert_eq!(ErrorKind::NotFound, remove_file(&path).unwrap_err().kind());
// Reading the metadata of a non-existing file should fail with a "not found" error.
if cfg!(target_os = "linux") { // FIXME: Implement stat64 for macos.
assert_eq!(ErrorKind::NotFound, test_metadata(bytes, &path).unwrap_err().kind());
}
}