1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990
//! Various utilities for working with files and paths.
use anyhow::{Context, Result};
use filetime::FileTime;
use std::env;
use std::ffi::{OsStr, OsString};
use std::fs::{self, File, Metadata, OpenOptions};
use std::io;
use std::io::prelude::*;
use std::iter;
use std::path::{Component, Path, PathBuf};
use tempfile::Builder as TempFileBuilder;
/// Joins paths into a string suitable for the `PATH` environment variable.
///
/// This is equivalent to [`std::env::join_paths`], but includes a more
/// detailed error message. The given `env` argument is the name of the
/// environment variable this is will be used for, which is included in the
/// error message.
pub fn join_paths<T: AsRef<OsStr>>(paths: &[T], env: &str) -> Result<OsString> {
env::join_paths(paths.iter()).with_context(|| {
let mut message = format!(
"failed to join paths from `${env}` together\n\n\
Check if any of path segments listed below contain an \
unterminated quote character or path separator:"
);
for path in paths {
use std::fmt::Write;
write!(&mut message, "\n {:?}", Path::new(path)).unwrap();
}
message
})
}
/// Returns the name of the environment variable used for searching for
/// dynamic libraries.
pub fn dylib_path_envvar() -> &'static str {
if cfg!(windows) {
"PATH"
} else if cfg!(target_os = "macos") {
// When loading and linking a dynamic library or bundle, dlopen
// searches in LD_LIBRARY_PATH, DYLD_LIBRARY_PATH, PWD, and
// DYLD_FALLBACK_LIBRARY_PATH.
// In the Mach-O format, a dynamic library has an "install path."
// Clients linking against the library record this path, and the
// dynamic linker, dyld, uses it to locate the library.
// dyld searches DYLD_LIBRARY_PATH *before* the install path.
// dyld searches DYLD_FALLBACK_LIBRARY_PATH only if it cannot
// find the library in the install path.
// Setting DYLD_LIBRARY_PATH can easily have unintended
// consequences.
//
// Also, DYLD_LIBRARY_PATH appears to have significant performance
// penalty starting in 10.13. Cargo's testsuite ran more than twice as
// slow with it on CI.
"DYLD_FALLBACK_LIBRARY_PATH"
} else if cfg!(target_os = "aix") {
"LIBPATH"
} else {
"LD_LIBRARY_PATH"
}
}
/// Returns a list of directories that are searched for dynamic libraries.
///
/// Note that some operating systems will have defaults if this is empty that
/// will need to be dealt with.
pub fn dylib_path() -> Vec<PathBuf> {
match env::var_os(dylib_path_envvar()) {
Some(var) => env::split_paths(&var).collect(),
None => Vec::new(),
}
}
/// Normalize a path, removing things like `.` and `..`.
///
/// CAUTION: This does not resolve symlinks (unlike
/// [`std::fs::canonicalize`]). This may cause incorrect or surprising
/// behavior at times. This should be used carefully. Unfortunately,
/// [`std::fs::canonicalize`] can be hard to use correctly, since it can often
/// fail, or on Windows returns annoying device paths. This is a problem Cargo
/// needs to improve on.
pub fn normalize_path(path: &Path) -> PathBuf {
let mut components = path.components().peekable();
let mut ret = if let Some(c @ Component::Prefix(..)) = components.peek().cloned() {
components.next();
PathBuf::from(c.as_os_str())
} else {
PathBuf::new()
};
for component in components {
match component {
Component::Prefix(..) => unreachable!(),
Component::RootDir => {
ret.push(component.as_os_str());
}
Component::CurDir => {}
Component::ParentDir => {
ret.pop();
}
Component::Normal(c) => {
ret.push(c);
}
}
}
ret
}
/// Returns the absolute path of where the given executable is located based
/// on searching the `PATH` environment variable.
///
/// Returns an error if it cannot be found.
pub fn resolve_executable(exec: &Path) -> Result<PathBuf> {
if exec.components().count() == 1 {
let paths = env::var_os("PATH").ok_or_else(|| anyhow::format_err!("no PATH"))?;
let candidates = env::split_paths(&paths).flat_map(|path| {
let candidate = path.join(&exec);
let with_exe = if env::consts::EXE_EXTENSION.is_empty() {
None
} else {
Some(candidate.with_extension(env::consts::EXE_EXTENSION))
};
iter::once(candidate).chain(with_exe)
});
for candidate in candidates {
if candidate.is_file() {
return Ok(candidate);
}
}
anyhow::bail!("no executable for `{}` found in PATH", exec.display())
} else {
Ok(exec.into())
}
}
/// Returns metadata for a file (follows symlinks).
///
/// Equivalent to [`std::fs::metadata`] with better error messages.
pub fn metadata<P: AsRef<Path>>(path: P) -> Result<Metadata> {
let path = path.as_ref();
std::fs::metadata(path)
.with_context(|| format!("failed to load metadata for path `{}`", path.display()))
}
/// Returns metadata for a file without following symlinks.
///
/// Equivalent to [`std::fs::metadata`] with better error messages.
pub fn symlink_metadata<P: AsRef<Path>>(path: P) -> Result<Metadata> {
let path = path.as_ref();
std::fs::symlink_metadata(path)
.with_context(|| format!("failed to load metadata for path `{}`", path.display()))
}
/// Reads a file to a string.
///
/// Equivalent to [`std::fs::read_to_string`] with better error messages.
pub fn read(path: &Path) -> Result<String> {
match String::from_utf8(read_bytes(path)?) {
Ok(s) => Ok(s),
Err(_) => anyhow::bail!("path at `{}` was not valid utf-8", path.display()),
}
}
/// Reads a file into a bytes vector.
///
/// Equivalent to [`std::fs::read`] with better error messages.
pub fn read_bytes(path: &Path) -> Result<Vec<u8>> {
fs::read(path).with_context(|| format!("failed to read `{}`", path.display()))
}
/// Writes a file to disk.
///
/// Equivalent to [`std::fs::write`] with better error messages.
pub fn write<P: AsRef<Path>, C: AsRef<[u8]>>(path: P, contents: C) -> Result<()> {
let path = path.as_ref();
fs::write(path, contents.as_ref())
.with_context(|| format!("failed to write `{}`", path.display()))
}
/// Writes a file to disk atomically.
///
/// write_atomic uses tempfile::persist to accomplish atomic writes.
pub fn write_atomic<P: AsRef<Path>, C: AsRef<[u8]>>(path: P, contents: C) -> Result<()> {
let path = path.as_ref();
// On unix platforms, get the permissions of the original file. Copy only the user/group/other
// read/write/execute permission bits. The tempfile lib defaults to an initial mode of 0o600,
// and we'll set the proper permissions after creating the file.
#[cfg(unix)]
let perms = path.metadata().ok().map(|meta| {
use std::os::unix::fs::PermissionsExt;
// these constants are u16 on macOS
let mask = u32::from(libc::S_IRWXU | libc::S_IRWXG | libc::S_IRWXO);
let mode = meta.permissions().mode() & mask;
std::fs::Permissions::from_mode(mode)
});
let mut tmp = TempFileBuilder::new()
.prefix(path.file_name().unwrap())
.tempfile_in(path.parent().unwrap())?;
tmp.write_all(contents.as_ref())?;
// On unix platforms, set the permissions on the newly created file. We can use fchmod (called
// by the std lib; subject to change) which ignores the umask so that the new file has the same
// permissions as the old file.
#[cfg(unix)]
if let Some(perms) = perms {
tmp.as_file().set_permissions(perms)?;
}
tmp.persist(path)?;
Ok(())
}
/// Equivalent to [`write()`], but does not write anything if the file contents
/// are identical to the given contents.
pub fn write_if_changed<P: AsRef<Path>, C: AsRef<[u8]>>(path: P, contents: C) -> Result<()> {
(|| -> Result<()> {
let contents = contents.as_ref();
let mut f = OpenOptions::new()
.read(true)
.write(true)
.create(true)
.open(&path)?;
let mut orig = Vec::new();
f.read_to_end(&mut orig)?;
if orig != contents {
f.set_len(0)?;
f.seek(io::SeekFrom::Start(0))?;
f.write_all(contents)?;
}
Ok(())
})()
.with_context(|| format!("failed to write `{}`", path.as_ref().display()))?;
Ok(())
}
/// Equivalent to [`write()`], but appends to the end instead of replacing the
/// contents.
pub fn append(path: &Path, contents: &[u8]) -> Result<()> {
(|| -> Result<()> {
let mut f = OpenOptions::new()
.write(true)
.append(true)
.create(true)
.open(path)?;
f.write_all(contents)?;
Ok(())
})()
.with_context(|| format!("failed to write `{}`", path.display()))?;
Ok(())
}
/// Creates a new file.
pub fn create<P: AsRef<Path>>(path: P) -> Result<File> {
let path = path.as_ref();
File::create(path).with_context(|| format!("failed to create file `{}`", path.display()))
}
/// Opens an existing file.
pub fn open<P: AsRef<Path>>(path: P) -> Result<File> {
let path = path.as_ref();
File::open(path).with_context(|| format!("failed to open file `{}`", path.display()))
}
/// Returns the last modification time of a file.
pub fn mtime(path: &Path) -> Result<FileTime> {
let meta = metadata(path)?;
Ok(FileTime::from_last_modification_time(&meta))
}
/// Returns the maximum mtime of the given path, recursing into
/// subdirectories, and following symlinks.
pub fn mtime_recursive(path: &Path) -> Result<FileTime> {
let meta = metadata(path)?;
if !meta.is_dir() {
return Ok(FileTime::from_last_modification_time(&meta));
}
let max_meta = walkdir::WalkDir::new(path)
.follow_links(true)
.into_iter()
.filter_map(|e| match e {
Ok(e) => Some(e),
Err(e) => {
// Ignore errors while walking. If Cargo can't access it, the
// build script probably can't access it, either.
tracing::debug!("failed to determine mtime while walking directory: {}", e);
None
}
})
.filter_map(|e| {
if e.path_is_symlink() {
// Use the mtime of both the symlink and its target, to
// handle the case where the symlink is modified to a
// different target.
let sym_meta = match std::fs::symlink_metadata(e.path()) {
Ok(m) => m,
Err(err) => {
// I'm not sure when this is really possible (maybe a
// race with unlinking?). Regardless, if Cargo can't
// read it, the build script probably can't either.
tracing::debug!(
"failed to determine mtime while fetching symlink metadata of {}: {}",
e.path().display(),
err
);
return None;
}
};
let sym_mtime = FileTime::from_last_modification_time(&sym_meta);
// Walkdir follows symlinks.
match e.metadata() {
Ok(target_meta) => {
let target_mtime = FileTime::from_last_modification_time(&target_meta);
Some(sym_mtime.max(target_mtime))
}
Err(err) => {
// Can't access the symlink target. If Cargo can't
// access it, the build script probably can't access
// it either.
tracing::debug!(
"failed to determine mtime of symlink target for {}: {}",
e.path().display(),
err
);
Some(sym_mtime)
}
}
} else {
let meta = match e.metadata() {
Ok(m) => m,
Err(err) => {
// I'm not sure when this is really possible (maybe a
// race with unlinking?). Regardless, if Cargo can't
// read it, the build script probably can't either.
tracing::debug!(
"failed to determine mtime while fetching metadata of {}: {}",
e.path().display(),
err
);
return None;
}
};
Some(FileTime::from_last_modification_time(&meta))
}
})
.max()
// or_else handles the case where there are no files in the directory.
.unwrap_or_else(|| FileTime::from_last_modification_time(&meta));
Ok(max_meta)
}
/// Record the current time on the filesystem (using the filesystem's clock)
/// using a file at the given directory. Returns the current time.
pub fn set_invocation_time(path: &Path) -> Result<FileTime> {
// note that if `FileTime::from_system_time(SystemTime::now());` is determined to be sufficient,
// then this can be removed.
let timestamp = path.join("invoked.timestamp");
write(
×tamp,
"This file has an mtime of when this was started.",
)?;
let ft = mtime(×tamp)?;
tracing::debug!("invocation time for {:?} is {}", path, ft);
Ok(ft)
}
/// Converts a path to UTF-8 bytes.
pub fn path2bytes(path: &Path) -> Result<&[u8]> {
#[cfg(unix)]
{
use std::os::unix::prelude::*;
Ok(path.as_os_str().as_bytes())
}
#[cfg(windows)]
{
match path.as_os_str().to_str() {
Some(s) => Ok(s.as_bytes()),
None => Err(anyhow::format_err!(
"invalid non-unicode path: {}",
path.display()
)),
}
}
}
/// Converts UTF-8 bytes to a path.
pub fn bytes2path(bytes: &[u8]) -> Result<PathBuf> {
#[cfg(unix)]
{
use std::os::unix::prelude::*;
Ok(PathBuf::from(OsStr::from_bytes(bytes)))
}
#[cfg(windows)]
{
use std::str;
match str::from_utf8(bytes) {
Ok(s) => Ok(PathBuf::from(s)),
Err(..) => Err(anyhow::format_err!("invalid non-unicode path")),
}
}
}
/// Returns an iterator that walks up the directory hierarchy towards the root.
///
/// Each item is a [`Path`]. It will start with the given path, finishing at
/// the root. If the `stop_root_at` parameter is given, it will stop at the
/// given path (which will be the last item).
pub fn ancestors<'a>(path: &'a Path, stop_root_at: Option<&Path>) -> PathAncestors<'a> {
PathAncestors::new(path, stop_root_at)
}
pub struct PathAncestors<'a> {
current: Option<&'a Path>,
stop_at: Option<PathBuf>,
}
impl<'a> PathAncestors<'a> {
fn new(path: &'a Path, stop_root_at: Option<&Path>) -> PathAncestors<'a> {
let stop_at = env::var("__CARGO_TEST_ROOT")
.ok()
.map(PathBuf::from)
.or_else(|| stop_root_at.map(|p| p.to_path_buf()));
PathAncestors {
current: Some(path),
//HACK: avoid reading `~/.cargo/config` when testing Cargo itself.
stop_at,
}
}
}
impl<'a> Iterator for PathAncestors<'a> {
type Item = &'a Path;
fn next(&mut self) -> Option<&'a Path> {
if let Some(path) = self.current {
self.current = path.parent();
if let Some(ref stop_at) = self.stop_at {
if path == stop_at {
self.current = None;
}
}
Some(path)
} else {
None
}
}
}
/// Equivalent to [`std::fs::create_dir_all`] with better error messages.
pub fn create_dir_all(p: impl AsRef<Path>) -> Result<()> {
_create_dir_all(p.as_ref())
}
fn _create_dir_all(p: &Path) -> Result<()> {
fs::create_dir_all(p)
.with_context(|| format!("failed to create directory `{}`", p.display()))?;
Ok(())
}
/// Equivalent to [`std::fs::remove_dir_all`] with better error messages.
///
/// This does *not* follow symlinks.
pub fn remove_dir_all<P: AsRef<Path>>(p: P) -> Result<()> {
_remove_dir_all(p.as_ref()).or_else(|prev_err| {
// `std::fs::remove_dir_all` is highly specialized for different platforms
// and may be more reliable than a simple walk. We try the walk first in
// order to report more detailed errors.
fs::remove_dir_all(p.as_ref()).with_context(|| {
format!(
"{:?}\n\nError: failed to remove directory `{}`",
prev_err,
p.as_ref().display(),
)
})
})
}
fn _remove_dir_all(p: &Path) -> Result<()> {
if symlink_metadata(p)?.is_symlink() {
return remove_file(p);
}
let entries = p
.read_dir()
.with_context(|| format!("failed to read directory `{}`", p.display()))?;
for entry in entries {
let entry = entry?;
let path = entry.path();
if entry.file_type()?.is_dir() {
remove_dir_all(&path)?;
} else {
remove_file(&path)?;
}
}
remove_dir(&p)
}
/// Equivalent to [`std::fs::remove_dir`] with better error messages.
pub fn remove_dir<P: AsRef<Path>>(p: P) -> Result<()> {
_remove_dir(p.as_ref())
}
fn _remove_dir(p: &Path) -> Result<()> {
fs::remove_dir(p).with_context(|| format!("failed to remove directory `{}`", p.display()))?;
Ok(())
}
/// Equivalent to [`std::fs::remove_file`] with better error messages.
///
/// If the file is readonly, this will attempt to change the permissions to
/// force the file to be deleted.
/// On Windows, if the file is a symlink to a directory, this will attempt to remove
/// the symlink itself.
pub fn remove_file<P: AsRef<Path>>(p: P) -> Result<()> {
_remove_file(p.as_ref())
}
fn _remove_file(p: &Path) -> Result<()> {
// For Windows, we need to check if the file is a symlink to a directory
// and remove the symlink itself by calling `remove_dir` instead of
// `remove_file`.
#[cfg(target_os = "windows")]
{
use std::os::windows::fs::FileTypeExt;
let metadata = symlink_metadata(p)?;
let file_type = metadata.file_type();
if file_type.is_symlink_dir() {
return remove_symlink_dir_with_permission_check(p);
}
}
remove_file_with_permission_check(p)
}
#[cfg(target_os = "windows")]
fn remove_symlink_dir_with_permission_check(p: &Path) -> Result<()> {
remove_with_permission_check(fs::remove_dir, p)
.with_context(|| format!("failed to remove symlink dir `{}`", p.display()))
}
fn remove_file_with_permission_check(p: &Path) -> Result<()> {
remove_with_permission_check(fs::remove_file, p)
.with_context(|| format!("failed to remove file `{}`", p.display()))
}
fn remove_with_permission_check<F, P>(remove_func: F, p: P) -> io::Result<()>
where
F: Fn(P) -> io::Result<()>,
P: AsRef<Path> + Clone,
{
match remove_func(p.clone()) {
Ok(()) => Ok(()),
Err(e) => {
if e.kind() == io::ErrorKind::PermissionDenied
&& set_not_readonly(p.as_ref()).unwrap_or(false)
{
remove_func(p)
} else {
Err(e)
}
}
}
}
fn set_not_readonly(p: &Path) -> io::Result<bool> {
let mut perms = p.metadata()?.permissions();
if !perms.readonly() {
return Ok(false);
}
perms.set_readonly(false);
fs::set_permissions(p, perms)?;
Ok(true)
}
/// Hardlink (file) or symlink (dir) src to dst if possible, otherwise copy it.
///
/// If the destination already exists, it is removed before linking.
pub fn link_or_copy(src: impl AsRef<Path>, dst: impl AsRef<Path>) -> Result<()> {
let src = src.as_ref();
let dst = dst.as_ref();
_link_or_copy(src, dst)
}
fn _link_or_copy(src: &Path, dst: &Path) -> Result<()> {
tracing::debug!("linking {} to {}", src.display(), dst.display());
if same_file::is_same_file(src, dst).unwrap_or(false) {
return Ok(());
}
// NB: we can't use dst.exists(), as if dst is a broken symlink,
// dst.exists() will return false. This is problematic, as we still need to
// unlink dst in this case. symlink_metadata(dst).is_ok() will tell us
// whether dst exists *without* following symlinks, which is what we want.
if fs::symlink_metadata(dst).is_ok() {
remove_file(&dst)?;
}
let link_result = if src.is_dir() {
#[cfg(target_os = "redox")]
use std::os::redox::fs::symlink;
#[cfg(unix)]
use std::os::unix::fs::symlink;
#[cfg(windows)]
// FIXME: This should probably panic or have a copy fallback. Symlinks
// are not supported in all windows environments. Currently symlinking
// is only used for .dSYM directories on macos, but this shouldn't be
// accidentally relied upon.
use std::os::windows::fs::symlink_dir as symlink;
let dst_dir = dst.parent().unwrap();
let src = if src.starts_with(dst_dir) {
src.strip_prefix(dst_dir).unwrap()
} else {
src
};
symlink(src, dst)
} else {
if cfg!(target_os = "macos") {
// There seems to be a race condition with APFS when hard-linking
// binaries. Gatekeeper does not have signing or hash information
// stored in kernel when running the process. Therefore killing it.
// This problem does not appear when copying files as kernel has
// time to process it. Note that: fs::copy on macos is using
// CopyOnWrite (syscall fclonefileat) which should be as fast as
// hardlinking. See these issues for the details:
//
// * https://github.com/rust-lang/cargo/issues/7821
// * https://github.com/rust-lang/cargo/issues/10060
fs::copy(src, dst).map_or_else(
|e| {
if e.raw_os_error()
.map_or(false, |os_err| os_err == 35 /* libc::EAGAIN */)
{
tracing::info!("copy failed {e:?}. falling back to fs::hard_link");
// Working around an issue copying too fast with zfs (probably related to
// https://github.com/openzfsonosx/zfs/issues/809)
// See https://github.com/rust-lang/cargo/issues/13838
fs::hard_link(src, dst)
} else {
Err(e)
}
},
|_| Ok(()),
)
} else {
fs::hard_link(src, dst)
}
};
link_result
.or_else(|err| {
tracing::debug!("link failed {}. falling back to fs::copy", err);
fs::copy(src, dst).map(|_| ())
})
.with_context(|| {
format!(
"failed to link or copy `{}` to `{}`",
src.display(),
dst.display()
)
})?;
Ok(())
}
/// Copies a file from one location to another.
///
/// Equivalent to [`std::fs::copy`] with better error messages.
pub fn copy<P: AsRef<Path>, Q: AsRef<Path>>(from: P, to: Q) -> Result<u64> {
let from = from.as_ref();
let to = to.as_ref();
fs::copy(from, to)
.with_context(|| format!("failed to copy `{}` to `{}`", from.display(), to.display()))
}
/// Changes the filesystem mtime (and atime if possible) for the given file.
///
/// This intentionally does not return an error, as this is sometimes not
/// supported on network filesystems. For the current uses in Cargo, this is a
/// "best effort" approach, and errors shouldn't be propagated.
pub fn set_file_time_no_err<P: AsRef<Path>>(path: P, time: FileTime) {
let path = path.as_ref();
match filetime::set_file_times(path, time, time) {
Ok(()) => tracing::debug!("set file mtime {} to {}", path.display(), time),
Err(e) => tracing::warn!(
"could not set mtime of {} to {}: {:?}",
path.display(),
time,
e
),
}
}
/// Strips `base` from `path`.
///
/// This canonicalizes both paths before stripping. This is useful if the
/// paths are obtained in different ways, and one or the other may or may not
/// have been normalized in some way.
pub fn strip_prefix_canonical<P: AsRef<Path>>(
path: P,
base: P,
) -> Result<PathBuf, std::path::StripPrefixError> {
// Not all filesystems support canonicalize. Just ignore if it doesn't work.
let safe_canonicalize = |path: &Path| match path.canonicalize() {
Ok(p) => p,
Err(e) => {
tracing::warn!("cannot canonicalize {:?}: {:?}", path, e);
path.to_path_buf()
}
};
let canon_path = safe_canonicalize(path.as_ref());
let canon_base = safe_canonicalize(base.as_ref());
canon_path.strip_prefix(canon_base).map(|p| p.to_path_buf())
}
/// Creates an excluded from cache directory atomically with its parents as needed.
///
/// The atomicity only covers creating the leaf directory and exclusion from cache. Any missing
/// parent directories will not be created in an atomic manner.
///
/// This function is idempotent and in addition to that it won't exclude ``p`` from cache if it
/// already exists.
pub fn create_dir_all_excluded_from_backups_atomic(p: impl AsRef<Path>) -> Result<()> {
let path = p.as_ref();
if path.is_dir() {
return Ok(());
}
let parent = path.parent().unwrap();
let base = path.file_name().unwrap();
create_dir_all(parent)?;
// We do this in two steps (first create a temporary directory and exclude
// it from backups, then rename it to the desired name. If we created the
// directory directly where it should be and then excluded it from backups
// we would risk a situation where cargo is interrupted right after the directory
// creation but before the exclusion the directory would remain non-excluded from
// backups because we only perform exclusion right after we created the directory
// ourselves.
//
// We need the tempdir created in parent instead of $TMP, because only then we can be
// easily sure that rename() will succeed (the new name needs to be on the same mount
// point as the old one).
let tempdir = TempFileBuilder::new().prefix(base).tempdir_in(parent)?;
exclude_from_backups(tempdir.path());
exclude_from_content_indexing(tempdir.path());
// Previously std::fs::create_dir_all() (through paths::create_dir_all()) was used
// here to create the directory directly and fs::create_dir_all() explicitly treats
// the directory being created concurrently by another thread or process as success,
// hence the check below to follow the existing behavior. If we get an error at
// rename() and suddenly the directory (which didn't exist a moment earlier) exists
// we can infer from it's another cargo process doing work.
if let Err(e) = fs::rename(tempdir.path(), path) {
if !path.exists() {
return Err(anyhow::Error::from(e))
.with_context(|| format!("failed to create directory `{}`", path.display()));
}
}
Ok(())
}
/// Mark an existing directory as excluded from backups and indexing.
///
/// Errors in marking it are ignored.
pub fn exclude_from_backups_and_indexing(p: impl AsRef<Path>) {
let path = p.as_ref();
exclude_from_backups(path);
exclude_from_content_indexing(path);
}
/// Marks the directory as excluded from archives/backups.
///
/// This is recommended to prevent derived/temporary files from bloating backups. There are two
/// mechanisms used to achieve this right now:
///
/// * A dedicated resource property excluding from Time Machine backups on macOS
/// * CACHEDIR.TAG files supported by various tools in a platform-independent way
fn exclude_from_backups(path: &Path) {
exclude_from_time_machine(path);
let file = path.join("CACHEDIR.TAG");
if !file.exists() {
let _ = std::fs::write(
file,
"Signature: 8a477f597d28d172789f06886806bc55
# This file is a cache directory tag created by cargo.
# For information about cache directory tags see https://bford.info/cachedir/
",
);
// Similarly to exclude_from_time_machine() we ignore errors here as it's an optional feature.
}
}
/// Marks the directory as excluded from content indexing.
///
/// This is recommended to prevent the content of derived/temporary files from being indexed.
/// This is very important for Windows users, as the live content indexing significantly slows
/// cargo's I/O operations.
///
/// This is currently a no-op on non-Windows platforms.
fn exclude_from_content_indexing(path: &Path) {
#[cfg(windows)]
{
use std::iter::once;
use std::os::windows::prelude::OsStrExt;
use windows_sys::Win32::Storage::FileSystem::{
GetFileAttributesW, SetFileAttributesW, FILE_ATTRIBUTE_NOT_CONTENT_INDEXED,
};
let path: Vec<u16> = path.as_os_str().encode_wide().chain(once(0)).collect();
unsafe {
SetFileAttributesW(
path.as_ptr(),
GetFileAttributesW(path.as_ptr()) | FILE_ATTRIBUTE_NOT_CONTENT_INDEXED,
);
}
}
#[cfg(not(windows))]
{
let _ = path;
}
}
#[cfg(not(target_os = "macos"))]
fn exclude_from_time_machine(_: &Path) {}
#[cfg(target_os = "macos")]
/// Marks files or directories as excluded from Time Machine on macOS
fn exclude_from_time_machine(path: &Path) {
use core_foundation::base::TCFType;
use core_foundation::{number, string, url};
use std::ptr;
// For compatibility with 10.7 a string is used instead of global kCFURLIsExcludedFromBackupKey
let is_excluded_key: Result<string::CFString, _> = "NSURLIsExcludedFromBackupKey".parse();
let path = url::CFURL::from_path(path, false);
if let (Some(path), Ok(is_excluded_key)) = (path, is_excluded_key) {
unsafe {
url::CFURLSetResourcePropertyForKey(
path.as_concrete_TypeRef(),
is_excluded_key.as_concrete_TypeRef(),
number::kCFBooleanTrue as *const _,
ptr::null_mut(),
);
}
}
// Errors are ignored, since it's an optional feature and failure
// doesn't prevent Cargo from working
}
#[cfg(test)]
mod tests {
use super::join_paths;
use super::write;
use super::write_atomic;
#[test]
fn write_works() {
let original_contents = "[dependencies]\nfoo = 0.1.0";
let tmpdir = tempfile::tempdir().unwrap();
let path = tmpdir.path().join("Cargo.toml");
write(&path, original_contents).unwrap();
let contents = std::fs::read_to_string(&path).unwrap();
assert_eq!(contents, original_contents);
}
#[test]
fn write_atomic_works() {
let original_contents = "[dependencies]\nfoo = 0.1.0";
let tmpdir = tempfile::tempdir().unwrap();
let path = tmpdir.path().join("Cargo.toml");
write_atomic(&path, original_contents).unwrap();
let contents = std::fs::read_to_string(&path).unwrap();
assert_eq!(contents, original_contents);
}
#[test]
#[cfg(unix)]
fn write_atomic_permissions() {
use std::os::unix::fs::PermissionsExt;
let original_perms = std::fs::Permissions::from_mode(u32::from(
libc::S_IRWXU | libc::S_IRGRP | libc::S_IWGRP | libc::S_IROTH,
));
let tmp = tempfile::Builder::new().tempfile().unwrap();
// need to set the permissions after creating the file to avoid umask
tmp.as_file()
.set_permissions(original_perms.clone())
.unwrap();
// after this call, the file at `tmp.path()` will not be the same as the file held by `tmp`
write_atomic(tmp.path(), "new").unwrap();
assert_eq!(std::fs::read_to_string(tmp.path()).unwrap(), "new");
let new_perms = std::fs::metadata(tmp.path()).unwrap().permissions();
let mask = u32::from(libc::S_IRWXU | libc::S_IRWXG | libc::S_IRWXO);
assert_eq!(original_perms.mode(), new_perms.mode() & mask);
}
#[test]
fn join_paths_lists_paths_on_error() {
let valid_paths = vec!["/testing/one", "/testing/two"];
// does not fail on valid input
let _joined = join_paths(&valid_paths, "TESTING1").unwrap();
#[cfg(unix)]
{
let invalid_paths = vec!["/testing/one", "/testing/t:wo/three"];
let err = join_paths(&invalid_paths, "TESTING2").unwrap_err();
assert_eq!(
err.to_string(),
"failed to join paths from `$TESTING2` together\n\n\
Check if any of path segments listed below contain an \
unterminated quote character or path separator:\
\n \"/testing/one\"\
\n \"/testing/t:wo/three\"\
"
);
}
#[cfg(windows)]
{
let invalid_paths = vec!["/testing/one", "/testing/t\"wo/three"];
let err = join_paths(&invalid_paths, "TESTING2").unwrap_err();
assert_eq!(
err.to_string(),
"failed to join paths from `$TESTING2` together\n\n\
Check if any of path segments listed below contain an \
unterminated quote character or path separator:\
\n \"/testing/one\"\
\n \"/testing/t\\\"wo/three\"\
"
);
}
}
#[test]
#[cfg(windows)]
fn test_remove_symlink_dir() {
use super::*;
use std::fs;
use std::os::windows::fs::symlink_dir;
let tmpdir = tempfile::tempdir().unwrap();
let dir_path = tmpdir.path().join("testdir");
let symlink_path = tmpdir.path().join("symlink");
fs::create_dir(&dir_path).unwrap();
symlink_dir(&dir_path, &symlink_path).expect("failed to create symlink");
assert!(symlink_path.exists());
assert!(remove_file(symlink_path.clone()).is_ok());
assert!(!symlink_path.exists());
assert!(dir_path.exists());
}
#[test]
#[cfg(windows)]
fn test_remove_symlink_file() {
use super::*;
use std::fs;
use std::os::windows::fs::symlink_file;
let tmpdir = tempfile::tempdir().unwrap();
let file_path = tmpdir.path().join("testfile");
let symlink_path = tmpdir.path().join("symlink");
fs::write(&file_path, b"test").unwrap();
symlink_file(&file_path, &symlink_path).expect("failed to create symlink");
assert!(symlink_path.exists());
assert!(remove_file(symlink_path.clone()).is_ok());
assert!(!symlink_path.exists());
assert!(file_path.exists());
}
}