1 use std::collections::HashMap;
2 use std::convert::{TryFrom, TryInto};
3 use std::fs::{remove_file, File, OpenOptions};
4 use std::io::{Read, Write};
5 use std::path::PathBuf;
6 use std::time::SystemTime;
8 use rustc::ty::layout::{Align, LayoutOf, Size};
10 use crate::stacked_borrows::Tag;
12 use helpers::immty_from_uint_checked;
13 use shims::time::system_time_to_duration;
16 pub struct FileHandle {
20 pub struct FileHandler {
21 handles: HashMap<i32, FileHandle>,
25 impl Default for FileHandler {
26 fn default() -> Self {
28 handles: Default::default(),
29 // 0, 1 and 2 are reserved for stdin, stdout and stderr.
35 impl<'mir, 'tcx> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
36 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
39 path_op: OpTy<'tcx, Tag>,
40 flag_op: OpTy<'tcx, Tag>,
41 ) -> InterpResult<'tcx, i32> {
42 let this = self.eval_context_mut();
44 this.check_no_isolation("open")?;
46 let flag = this.read_scalar(flag_op)?.to_i32()?;
48 let mut options = OpenOptions::new();
50 let o_rdonly = this.eval_libc_i32("O_RDONLY")?;
51 let o_wronly = this.eval_libc_i32("O_WRONLY")?;
52 let o_rdwr = this.eval_libc_i32("O_RDWR")?;
53 // The first two bits of the flag correspond to the access mode in linux, macOS and
54 // windows. We need to check that in fact the access mode flags for the current platform
55 // only use these two bits, otherwise we are in an unsupported platform and should error.
56 if (o_rdonly | o_wronly | o_rdwr) & !0b11 != 0 {
57 throw_unsup_format!("Access mode flags on this platform are unsupported");
59 // Now we check the access mode
60 let access_mode = flag & 0b11;
62 if access_mode == o_rdonly {
64 } else if access_mode == o_wronly {
66 } else if access_mode == o_rdwr {
67 options.read(true).write(true);
69 throw_unsup_format!("Unsupported access mode {:#x}", access_mode);
71 // We need to check that there aren't unsupported options in `flag`. For this we try to
72 // reproduce the content of `flag` in the `mirror` variable using only the supported
74 let mut mirror = access_mode;
76 let o_append = this.eval_libc_i32("O_APPEND")?;
77 if flag & o_append != 0 {
81 let o_trunc = this.eval_libc_i32("O_TRUNC")?;
82 if flag & o_trunc != 0 {
83 options.truncate(true);
86 let o_creat = this.eval_libc_i32("O_CREAT")?;
87 if flag & o_creat != 0 {
91 let o_cloexec = this.eval_libc_i32("O_CLOEXEC")?;
92 if flag & o_cloexec != 0 {
93 // We do not need to do anything for this flag because `std` already sets it.
94 // (Technically we do not support *not* setting this flag, but we ignore that.)
97 // If `flag` is not equal to `mirror`, there is an unsupported option enabled in `flag`,
98 // then we throw an error.
100 throw_unsup_format!("unsupported flags {:#x}", flag & !mirror);
103 let path = this.read_os_str_from_c_str(this.read_scalar(path_op)?.not_undef()?)?;
105 let fd = options.open(&path).map(|file| {
106 let mut fh = &mut this.machine.file_handler;
108 fh.handles.insert(fh.low, FileHandle { file }).unwrap_none();
112 this.try_unwrap_io_result(fd)
117 fd_op: OpTy<'tcx, Tag>,
118 cmd_op: OpTy<'tcx, Tag>,
119 _arg1_op: Option<OpTy<'tcx, Tag>>,
120 ) -> InterpResult<'tcx, i32> {
121 let this = self.eval_context_mut();
123 this.check_no_isolation("fcntl")?;
125 let fd = this.read_scalar(fd_op)?.to_i32()?;
126 let cmd = this.read_scalar(cmd_op)?.to_i32()?;
127 // We only support getting the flags for a descriptor.
128 if cmd == this.eval_libc_i32("F_GETFD")? {
129 // Currently this is the only flag that `F_GETFD` returns. It is OK to just return the
130 // `FD_CLOEXEC` value without checking if the flag is set for the file because `std`
131 // always sets this flag when opening a file. However we still need to check that the
132 // file itself is open.
133 if this.machine.file_handler.handles.contains_key(&fd) {
134 Ok(this.eval_libc_i32("FD_CLOEXEC")?)
136 this.handle_not_found()
139 throw_unsup_format!("The {:#x} command is not supported for `fcntl`)", cmd);
143 fn close(&mut self, fd_op: OpTy<'tcx, Tag>) -> InterpResult<'tcx, i32> {
144 let this = self.eval_context_mut();
146 this.check_no_isolation("close")?;
148 let fd = this.read_scalar(fd_op)?.to_i32()?;
150 if let Some(handle) = this.machine.file_handler.handles.remove(&fd) {
151 // `File::sync_all` does the checks that are done when closing a file. We do this to
152 // to handle possible errors correctly.
153 let result = this.try_unwrap_io_result(handle.file.sync_all().map(|_| 0i32));
154 // Now we actually close the file.
156 // And return the result.
159 this.handle_not_found()
165 fd_op: OpTy<'tcx, Tag>,
166 buf_op: OpTy<'tcx, Tag>,
167 count_op: OpTy<'tcx, Tag>,
168 ) -> InterpResult<'tcx, i64> {
169 let this = self.eval_context_mut();
171 this.check_no_isolation("read")?;
173 let fd = this.read_scalar(fd_op)?.to_i32()?;
174 let buf = this.read_scalar(buf_op)?.not_undef()?;
175 let count = this.read_scalar(count_op)?.to_machine_usize(&*this.tcx)?;
177 // Check that the *entire* buffer is actually valid memory.
178 this.memory.check_ptr_access(
180 Size::from_bytes(count),
181 Align::from_bytes(1).unwrap(),
184 // We cap the number of read bytes to the largest value that we are able to fit in both the
185 // host's and target's `isize`. This saves us from having to handle overflows later.
186 let count = count.min(this.isize_max() as u64).min(isize::max_value() as u64);
188 if let Some(handle) = this.machine.file_handler.handles.get_mut(&fd) {
189 // This can never fail because `count` was capped to be smaller than
190 // `isize::max_value()`.
191 let count = isize::try_from(count).unwrap();
192 // We want to read at most `count` bytes. We are sure that `count` is not negative
193 // because it was a target's `usize`. Also we are sure that its smaller than
194 // `usize::max_value()` because it is a host's `isize`.
195 let mut bytes = vec![0; count as usize];
199 // `File::read` never returns a value larger than `count`, so this cannot fail.
200 .map(|c| i64::try_from(c).unwrap());
204 // If reading to `bytes` did not fail, we write those bytes to the buffer.
205 this.memory.write_bytes(buf, bytes)?;
209 this.set_last_error_from_io_error(e)?;
214 this.handle_not_found()
220 fd_op: OpTy<'tcx, Tag>,
221 buf_op: OpTy<'tcx, Tag>,
222 count_op: OpTy<'tcx, Tag>,
223 ) -> InterpResult<'tcx, i64> {
224 let this = self.eval_context_mut();
226 this.check_no_isolation("write")?;
228 let fd = this.read_scalar(fd_op)?.to_i32()?;
229 let buf = this.read_scalar(buf_op)?.not_undef()?;
230 let count = this.read_scalar(count_op)?.to_machine_usize(&*this.tcx)?;
232 // Check that the *entire* buffer is actually valid memory.
233 this.memory.check_ptr_access(
235 Size::from_bytes(count),
236 Align::from_bytes(1).unwrap(),
239 // We cap the number of written bytes to the largest value that we are able to fit in both the
240 // host's and target's `isize`. This saves us from having to handle overflows later.
241 let count = count.min(this.isize_max() as u64).min(isize::max_value() as u64);
243 if let Some(handle) = this.machine.file_handler.handles.get_mut(&fd) {
244 let bytes = this.memory.read_bytes(buf, Size::from_bytes(count))?;
245 let result = handle.file.write(&bytes).map(|c| i64::try_from(c).unwrap());
246 this.try_unwrap_io_result(result)
248 this.handle_not_found()
252 fn unlink(&mut self, path_op: OpTy<'tcx, Tag>) -> InterpResult<'tcx, i32> {
253 let this = self.eval_context_mut();
255 this.check_no_isolation("unlink")?;
257 let path = this.read_os_str_from_c_str(this.read_scalar(path_op)?.not_undef()?)?;
259 let result = remove_file(path).map(|_| 0);
261 this.try_unwrap_io_result(result)
266 path_op: OpTy<'tcx, Tag>,
267 buf_op: OpTy<'tcx, Tag>,
268 ) -> InterpResult<'tcx, i32> {
269 let this = self.eval_context_mut();
271 if this.tcx.sess.target.target.target_os.to_lowercase() != "macos" {
272 throw_unsup_format!("The `stat` shim is only available for `macos` targets.")
275 let path_scalar = this.read_scalar(path_op)?.not_undef()?;
276 let path: PathBuf = this.read_os_str_from_c_str(path_scalar)?.into();
278 let buf = this.deref_operand(buf_op)?;
280 // `stat` always follows symlinks. `lstat` is used to get symlink metadata.
281 let metadata = match FileMetadata::new(this, path, true)? {
282 Some(metadata) => metadata,
283 None => return Ok(-1),
286 let mode: u16 = metadata.mode.to_u16()?;
288 let (access_sec, access_nsec) = metadata.accessed.unwrap_or((0, 0));
289 let (created_sec, created_nsec) = metadata.created.unwrap_or((0, 0));
290 let (modified_sec, modified_nsec) = metadata.modified.unwrap_or((0, 0));
292 let dev_t_layout = this.libc_ty_layout("dev_t")?;
293 let mode_t_layout = this.libc_ty_layout("mode_t")?;
294 let nlink_t_layout = this.libc_ty_layout("nlink_t")?;
295 let ino_t_layout = this.libc_ty_layout("ino_t")?;
296 let uid_t_layout = this.libc_ty_layout("uid_t")?;
297 let gid_t_layout = this.libc_ty_layout("gid_t")?;
298 let time_t_layout = this.libc_ty_layout("time_t")?;
299 let long_layout = this.libc_ty_layout("c_long")?;
300 let off_t_layout = this.libc_ty_layout("off_t")?;
301 let blkcnt_t_layout = this.libc_ty_layout("blkcnt_t")?;
302 let blksize_t_layout = this.libc_ty_layout("blksize_t")?;
303 let uint32_t_layout = this.libc_ty_layout("uint32_t")?;
305 // We need to add 32 bits of padding after `st_rdev` if we are on a 64-bit platform.
306 let pad_layout = if this.tcx.sess.target.ptr_width == 64 {
309 this.layout_of(this.tcx.mk_unit())?
313 immty_from_uint_checked(0u128, dev_t_layout)?, // st_dev
314 immty_from_uint_checked(mode, mode_t_layout)?, // st_mode
315 immty_from_uint_checked(0u128, nlink_t_layout)?, // st_nlink
316 immty_from_uint_checked(0u128, ino_t_layout)?, // st_ino
317 immty_from_uint_checked(0u128, uid_t_layout)?, // st_uid
318 immty_from_uint_checked(0u128, gid_t_layout)?, // st_gid
319 immty_from_uint_checked(0u128, dev_t_layout)?, // st_rdev
320 immty_from_uint_checked(0u128, pad_layout)?, // padding for 64-bit targets
321 immty_from_uint_checked(access_sec, time_t_layout)?, // st_atime
322 immty_from_uint_checked(access_nsec, long_layout)?, // st_atime_nsec
323 immty_from_uint_checked(modified_sec, time_t_layout)?, // st_mtime
324 immty_from_uint_checked(modified_nsec, long_layout)?, // st_mtime_nsec
325 immty_from_uint_checked(0u128, time_t_layout)?, // st_ctime
326 immty_from_uint_checked(0u128, long_layout)?, // st_ctime_nsec
327 immty_from_uint_checked(created_sec, time_t_layout)?, // st_birthtime
328 immty_from_uint_checked(created_nsec, long_layout)?, // st_birthtime_nsec
329 immty_from_uint_checked(metadata.size, off_t_layout)?, // st_size
330 immty_from_uint_checked(0u128, blkcnt_t_layout)?, // st_blocks
331 immty_from_uint_checked(0u128, blksize_t_layout)?, // st_blksize
332 immty_from_uint_checked(0u128, uint32_t_layout)?, // st_flags
333 immty_from_uint_checked(0u128, uint32_t_layout)?, // st_gen
336 this.write_packed_immediates(&buf, &imms)?;
343 dirfd_op: OpTy<'tcx, Tag>, // Should be an `int`
344 pathname_op: OpTy<'tcx, Tag>, // Should be a `const char *`
345 flags_op: OpTy<'tcx, Tag>, // Should be an `int`
346 _mask_op: OpTy<'tcx, Tag>, // Should be an `unsigned int`
347 statxbuf_op: OpTy<'tcx, Tag>, // Should be a `struct statx *`
348 ) -> InterpResult<'tcx, i32> {
349 let this = self.eval_context_mut();
351 this.check_no_isolation("statx")?;
353 if this.tcx.sess.target.target.target_os.to_lowercase() != "linux" {
354 throw_unsup_format!("The `statx` shim is only available for `linux` targets.")
357 let statxbuf_scalar = this.read_scalar(statxbuf_op)?.not_undef()?;
358 let pathname_scalar = this.read_scalar(pathname_op)?.not_undef()?;
360 // If the statxbuf or pathname pointers are null, the function fails with `EFAULT`.
361 if this.is_null(statxbuf_scalar)? || this.is_null(pathname_scalar)? {
362 let efault = this.eval_libc("EFAULT")?;
363 this.set_last_error(efault)?;
367 // Under normal circumstances, we would use `deref_operand(statxbuf_op)` to produce a
368 // proper `MemPlace` and then write the results of this function to it. However, the
369 // `syscall` function is untyped. This means that all the `statx` parameters are provided
370 // as `isize`s instead of having the proper types. Thus, we have to recover the layout of
371 // `statxbuf_op` by using the `libc::statx` struct type.
372 let statxbuf_place = {
373 // FIXME: This long path is required because `libc::statx` is an struct and also a
374 // function and `resolve_path` is returning the latter.
376 .resolve_path(&["libc", "unix", "linux_like", "linux", "gnu", "statx"])?
378 let statxbuf_ty = this.tcx.mk_mut_ptr(statx_ty);
379 let statxbuf_layout = this.layout_of(statxbuf_ty)?;
380 let statxbuf_imm = ImmTy::from_scalar(statxbuf_scalar, statxbuf_layout);
381 this.ref_to_mplace(statxbuf_imm)?
384 let path: PathBuf = this.read_os_str_from_c_str(pathname_scalar)?.into();
385 // `flags` should be a `c_int` but the `syscall` function provides an `isize`.
387 this.read_scalar(flags_op)?.to_machine_isize(&*this.tcx)?.try_into().map_err(|e| {
388 err_unsup_format!("Failed to convert pointer sized operand to integer: {}", e)
390 // `dirfd` should be a `c_int` but the `syscall` function provides an `isize`.
392 this.read_scalar(dirfd_op)?.to_machine_isize(&*this.tcx)?.try_into().map_err(|e| {
393 err_unsup_format!("Failed to convert pointer sized operand to integer: {}", e)
395 // we only support interpreting `path` as an absolute directory or as a directory relative
396 // to `dirfd` when the latter is `AT_FDCWD`. The behavior of `statx` with a relative path
397 // and a directory file descriptor other than `AT_FDCWD` is specified but it cannot be
398 // tested from `libstd`. If you found this error, please open an issue reporting it.
399 if !(path.is_absolute() || dirfd == this.eval_libc_i32("AT_FDCWD")?) {
401 "Using statx with a relative path and a file descriptor different from `AT_FDCWD` is not supported"
405 // the `_mask_op` paramter specifies the file information that the caller requested.
406 // However `statx` is allowed to return information that was not requested or to not
407 // return information that was requested. This `mask` represents the information we can
408 // actually provide in any host platform.
410 this.eval_libc("STATX_TYPE")?.to_u32()? | this.eval_libc("STATX_SIZE")?.to_u32()?;
412 // If the `AT_SYMLINK_NOFOLLOW` flag is set, we query the file's metadata without following
414 let follow_symlink = flags & this.eval_libc("AT_SYMLINK_NOFOLLOW")?.to_i32()? == 0;
416 let metadata = match FileMetadata::new(this, path, follow_symlink)? {
417 Some(metadata) => metadata,
418 None => return Ok(-1),
421 // The `mode` field specifies the type of the file and the permissions over the file for
422 // the owner, its group and other users. Given that we can only provide the file type
423 // without using platform specific methods, we only set the bits corresponding to the file
424 // type. This should be an `__u16` but `libc` provides its values as `u32`.
425 let mode: u16 = metadata
429 .unwrap_or_else(|_| bug!("libc contains bad value for constant"));
431 // We need to set the corresponding bits of `mask` if the access, creation and modification
432 // times were available. Otherwise we let them be zero.
433 let (access_sec, access_nsec) = metadata.accessed.map(|tup| {
434 mask |= this.eval_libc("STATX_ATIME")?.to_u32()?;
435 InterpResult::Ok(tup)
436 }).unwrap_or(Ok((0, 0)))?;
438 let (created_sec, created_nsec) = metadata.created.map(|tup| {
439 mask |= this.eval_libc("STATX_BTIME")?.to_u32()?;
440 InterpResult::Ok(tup)
441 }).unwrap_or(Ok((0, 0)))?;
443 let (modified_sec, modified_nsec) = metadata.modified.map(|tup| {
444 mask |= this.eval_libc("STATX_MTIME")?.to_u32()?;
445 InterpResult::Ok(tup)
446 }).unwrap_or(Ok((0, 0)))?;
448 let __u32_layout = this.libc_ty_layout("__u32")?;
449 let __u64_layout = this.libc_ty_layout("__u64")?;
450 let __u16_layout = this.libc_ty_layout("__u16")?;
452 // Now we transform all this fields into `ImmTy`s and write them to `statxbuf`. We write a
453 // zero for the unavailable fields.
455 immty_from_uint_checked(mask, __u32_layout)?, // stx_mask
456 immty_from_uint_checked(0u128, __u32_layout)?, // stx_blksize
457 immty_from_uint_checked(0u128, __u64_layout)?, // stx_attributes
458 immty_from_uint_checked(0u128, __u32_layout)?, // stx_nlink
459 immty_from_uint_checked(0u128, __u32_layout)?, // stx_uid
460 immty_from_uint_checked(0u128, __u32_layout)?, // stx_gid
461 immty_from_uint_checked(mode, __u16_layout)?, // stx_mode
462 immty_from_uint_checked(0u128, __u16_layout)?, // statx padding
463 immty_from_uint_checked(0u128, __u64_layout)?, // stx_ino
464 immty_from_uint_checked(metadata.size, __u64_layout)?, // stx_size
465 immty_from_uint_checked(0u128, __u64_layout)?, // stx_blocks
466 immty_from_uint_checked(0u128, __u64_layout)?, // stx_attributes
467 immty_from_uint_checked(access_sec, __u64_layout)?, // stx_atime.tv_sec
468 immty_from_uint_checked(access_nsec, __u32_layout)?, // stx_atime.tv_nsec
469 immty_from_uint_checked(0u128, __u32_layout)?, // statx_timestamp padding
470 immty_from_uint_checked(created_sec, __u64_layout)?, // stx_btime.tv_sec
471 immty_from_uint_checked(created_nsec, __u32_layout)?, // stx_btime.tv_nsec
472 immty_from_uint_checked(0u128, __u32_layout)?, // statx_timestamp padding
473 immty_from_uint_checked(0u128, __u64_layout)?, // stx_ctime.tv_sec
474 immty_from_uint_checked(0u128, __u32_layout)?, // stx_ctime.tv_nsec
475 immty_from_uint_checked(0u128, __u32_layout)?, // statx_timestamp padding
476 immty_from_uint_checked(modified_sec, __u64_layout)?, // stx_mtime.tv_sec
477 immty_from_uint_checked(modified_nsec, __u32_layout)?, // stx_mtime.tv_nsec
478 immty_from_uint_checked(0u128, __u32_layout)?, // statx_timestamp padding
479 immty_from_uint_checked(0u128, __u64_layout)?, // stx_rdev_major
480 immty_from_uint_checked(0u128, __u64_layout)?, // stx_rdev_minor
481 immty_from_uint_checked(0u128, __u64_layout)?, // stx_dev_major
482 immty_from_uint_checked(0u128, __u64_layout)?, // stx_dev_minor
485 this.write_packed_immediates(&statxbuf_place, &imms)?;
490 /// Function used when a handle is not found inside `FileHandler`. It returns `Ok(-1)`and sets
491 /// the last OS error to `libc::EBADF` (invalid file descriptor). This function uses
492 /// `T: From<i32>` instead of `i32` directly because some fs functions return different integer
493 /// types (like `read`, that returns an `i64`).
494 fn handle_not_found<T: From<i32>>(&mut self) -> InterpResult<'tcx, T> {
495 let this = self.eval_context_mut();
496 let ebadf = this.eval_libc("EBADF")?;
497 this.set_last_error(ebadf)?;
502 /// Extracts the number of seconds and nanoseconds elapsed between `time` and the unix epoch when
503 /// `time` is Ok. Returns `None` if `time` is an error. Fails if `time` happens before the unix
505 fn extract_sec_and_nsec<'tcx>(
506 time: std::io::Result<SystemTime>
507 ) -> InterpResult<'tcx, Option<(u64, u32)>> {
508 time.ok().map(|time| {
509 let duration = system_time_to_duration(&time)?;
510 Ok((duration.as_secs(), duration.subsec_nanos()))
514 /// Stores a file's metadata in order to avoid code duplication in the different metadata related
516 struct FileMetadata {
519 created: Option<(u64, u32)>,
520 accessed: Option<(u64, u32)>,
521 modified: Option<(u64, u32)>,
526 ecx: &mut MiriEvalContext<'mir, 'tcx>,
529 ) -> InterpResult<'tcx, Option<FileMetadata>> {
530 let metadata = if follow_symlink {
531 std::fs::metadata(path)
533 // FIXME: metadata for symlinks need testing.
534 std::fs::symlink_metadata(path)
537 let metadata = match metadata {
538 Ok(metadata) => metadata,
540 ecx.set_last_error_from_io_error(e)?;
545 let file_type = metadata.file_type();
547 let mode_name = if file_type.is_file() {
549 } else if file_type.is_dir() {
555 let mode = ecx.eval_libc(mode_name)?;
557 let size = metadata.len();
559 let created = extract_sec_and_nsec(metadata.created())?;
560 let accessed = extract_sec_and_nsec(metadata.accessed())?;
561 let modified = extract_sec_and_nsec(metadata.modified())?;
563 // FIXME: Provide more fields using platform specific methods.
564 Ok(Some(FileMetadata { mode, size, created, accessed, modified }))