Windows: Allow `File::create` to work on hidden files
This makes `OpenOptions::new().write(true).create(true).truncate(true).open(&path)` work if the path exists and is a hidden file. Previously it would fail with access denied.
This makes it consistent with `OpenOptions::new().write(true).truncate(true).open(&path)` (note the lack of `create`) which does not have this restriction. It's also more consistent with other platforms.
Fixes#115745 (see that issue for more details).
Time in UNIX system calls counts from the epoch, 1970-01-01. The timespec
struct used in various system calls represents this as a number of seconds and
a number of nanoseconds. Nanoseconds are required to be between 0 and
999_999_999, because the portion outside that range should be represented in
the seconds field; if nanoseconds were larger than 999_999_999, the seconds
field should go up instead.
Suppose you ask for the time 1969-12-31, what time is that? On UNIX systems
that support times before the epoch, that's seconds=-86400, one day before the
epoch. But now, suppose you ask for the time 1969-12-31 23:59:00.1. In other
words, a tenth of a second after one minute before the epoch. On most UNIX
systems, that's represented as seconds=-60, nanoseconds=100_000_000. The macOS
bug is that it returns seconds=-59, nanoseconds=-900_000_000.
While that's in some sense an accurate description of the time (59.9 seconds
before the epoch), that violates the invariant of the timespec data structure:
nanoseconds must be between 0 and 999999999. This causes this assertion in the
Rust standard library.
So, on macOS, if we get a Timespec value with seconds less than or equal to
zero, and nanoseconds between -999_999_999 and -1 (inclusive), we can add
1_000_000_000 to the nanoseconds and subtract 1 from the seconds, and then
convert. The resulting timespec value is still accepted by macOS, and when fed
back into the OS, produces the same results. (If you set a file's mtime with
that timestamp, then read it back, you get back the one with negative
nanoseconds again.)
Co-authored-by: Josh Triplett <josh@joshtriplett.org>
Previously it failed on Windows if the file had the `FILE_ATTRIBUTE_HIDDEN` attribute set. This was inconsistent with `OpenOptions::new().write(true).truncate(true)` which can truncate an existing hidden file.
Make std tests pass on newer Android
Newer versions of Android forbid the creation of hardlinks as well as Unix domain sockets in the /data filesystem via SELinux rules, which causes several tests depending on this behavior to fail. So let's skip these tests on Android if we see an EACCES from one of these syscalls. To achieve this, introduce a macro with the horrible name of or_panic_or_skip_on_android_eacces (better suggestions welcome) which skips (returns from) the test if an EACCES return value is seen on Android.
This can be done by simply changing the `\??\` prefix to `\\?\` and then attempting to convert to a user path.
Currently it simply strips off the prefix which could lead to the wrong path being returned (e.g. if it's not a drive path or if the path contains trailing spaces, etc).
Implement read_buf for TcpStream, Stdin, StdinLock, ChildStdout,
ChildStderr (and internally for AnonPipe, Handle, Socket), so
that it skips buffer initialization.
The other provided methods like read_to_string and read_to_end are
implemented in terms of read_buf and so benefit from the optimization
as well.
This commit also implements read_vectored and is_read_vectored where
applicable.
Newer versions of Android forbid the creation of hardlinks as well as
Unix domain sockets in the /data filesystem via SELinux rules, which
causes several tests depending on this behavior to fail. So let's
skip these tests on Android with an #[ignore] directive.
Bug #50619 was fixed by adding an end_of_stream flag in #50630.
Unfortunately, that fix only applied to the readdir_r() path. When I
switched Linux to use readdir() in #92778, I inadvertently reintroduced
the bug on that platform. Other platforms that had always used
readdir() were presumably never fixed.
This patch enables end_of_stream for all platforms, and adds a
Linux-specific regression test that should hopefully prevent the bug
from being reintroduced again.
Usually opening a file handle with access set to metadata only will always succeed, even if the file is locked. However some special system files, such as `C:\hiberfil.sys`, are locked by the system in a way that denies even that. So as a fallback we try reading the cached metadata from the directory.
Fix for localized windows editions in testcase fn read_link() Issue#93211
This PR aims to fix the issue with localized windows versions that do not necessarily have the folder "Documents and settings" in English.
The idea was provided by `@the8472.` We check if the "CI" environment variable is set, then we always check for the "Documents and Settings"-folder, otherwise we check if the folder exists on the local machine, and if not we skip this assert.
Resoles #93211.
This updates the standard library's documentation to use the new syntax. The
documentation is worthwhile to update as it should be more idiomatic
(particularly for features like this, which are nice for users to get acquainted
with). The general codebase is likely more hassle than benefit to update: it'll
hurt git blame, and generally updates can be done by folks updating the code if
(and when) that makes things more readable with the new format.
A few places in the compiler and library code are updated (mostly just due to
already having been done when this commit was first authored).
On old macos systems, `fs::hard_link()` will follow symlinks.
This changes the test `symlink_hard_link` to exit early on
these systems, so that tests can pass.
Define `fs::hard_link` to not follow symlinks.
POSIX leaves it [implementation-defined] whether `link` follows symlinks.
In practice, for example, on Linux it does not and on FreeBSD it does.
So, switch to `linkat`, so that we can pick a behavior rather than
depending on OS defaults.
Pick the option to not follow symlinks. This is somewhat arbitrary, but
seems the less surprising choice because hard linking is a very
low-level feature which requires the source and destination to be on
the same mounted filesystem, and following a symbolic link could end
up in a different mounted filesystem.
[implementation-defined]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/link.html
POSIX leaves it implementation-defined whether `link` follows symlinks.
In practice, for example, on Linux it does not and on FreeBSD it does.
So, switch to `linkat`, so that we can pick a behavior rather than
depending on OS defaults.
Pick the option to not follow symlinks. This is somewhat arbitrary, but
seems the less surprising choice because hard linking is a very
low-level feature which requires the source and destination to be on
the same mounted filesystem, and following a symbolic link could end
up in a different mounted filesystem.
Vadim Petrochenkov