Move to c/darwin.zig as they really are libSystem/libc imports/wrappers.
As an added bonus, get rid of the nasty `usingnamespace`s which are now
unneeded.
Finally, add `os.ptrace` but currently only implemented on darwin.
The OS layer expects pointer addresses to be inside the application's
address space even if the length is zero. Meanwhile, in Zig, slices may
have undefined pointer addresses when the length is zero. So this
function now modifies the iov_base fields when the length is zero.
This is a companion commit to b4893eb05565b2cb033c6ed88617d73faf878455.
The OS layer expects pointer addresses to be inside the application's
address space even if the length is zero. Meanwhile, in Zig, slices may
have undefined pointer addresses when the length is zero. So this
function now modifies the iov_base fields when the length is zero.
Today I found out that posix_spawn is trash. It's actually implemented
on top of fork/exec inside of libc (or libSystem in the case of macOS).
So, anything posix_spawn can do, we can do better. In particular, what
we can do better is handle spawning of child processes that are
potentially foreign binaries. If you try to spawn a wasm binary, for
example, posix spawn does the following:
* Goes ahead and creates a child process.
* The child process writes "foo.wasm: foo.wasm: cannot execute binary file"
to stderr (yes, it prints the filename twice).
* The child process then exits with code 126.
This behavior is indistinguishable from the binary being successfully
spawned, and then printing to stderr, and exiting with a failure -
something that is an extremely common occurrence.
Meanwhile, using the lower level fork/exec will simply return ENOEXEC
code from the execve syscall (which is mapped to zig error.InvalidExe).
The posix_spawn behavior means the zig build runner can't tell the
difference between a failure to run a foreign binary, and a binary that
did run, but failed in some other fashion. This is unacceptable, because
attempting to excecve is the proper way to support things like Rosetta.
Man page for posix lists EMFILE, man page for linux ENFILE.
Also posix says "The mmap() function adds an extra reference to the file
associated with the file descriptor fildes which is not removed by a
subsequent close() on that file descriptor. This reference is removed
when there are no more mappings to the file."
It sounds counter-intuitive, that a process limit but no system limit can
be exceeeded.
As far as I understand, fildes is only used for file descriptor backed mmaps.
- Fixes the first few code units of the name being omitted (it was using `@sizeOf(FILE_NAME_INFO)` as the start of the name bytes, but that includes the length of the dummy [1]u16 field and padding; instead the start should be the offset of the dummy [1]u16 field)
- Replaces kernel32.GetFileInformationByHandleEx call with ntdll.NtQueryInformationFile
+ Contributes towards #1840
- Checks that the handle is a named pipe first before querying and checking the name, which is a much faster call than NtQueryInformationFile (this was about a 10x speedup in my probably-not-so-good/take-it-with-a-grain-of-salt benchmarking)
In Linux when interacting with the virtual file system when writing
in invalid value to a file the OS will return errno 22 (INVAL).
Instead of triggering an unreachable, this change now returns a
newly introduced error.InvalidArgument.
In Linux when writing to various files in the virtual file system,
for example /sys/fs/cgroup, if you write an invalid value to a file
you'll get errno 16.
This change allows for these specific cases to be caught instead of
being lumped together in UnexpectedError.
Also add `std.fs.has_executable_bit` for doing conditional compilation.
This adds the linux syscalls for chmod and fchmodat, as well as the
extern libc function declarations.
Only `fchmodat` is added to `std.os`, and it is not yet added to std.fs.
This fixes a bug in std.net caused during the introduction of
meta.assumeSentinel due to the unfortunate semantics of mem.span()
This leaves only 3 remaining uses of meta.assumeSentinel() in the
standard library, each of which could be a simple @ptrCast([*:0]T, foo)
instead. I think this function should likely be removed.
- per darwin-xnu source, fcntl F_GETPATH will return ENOSPC when path
exceeds either user-supplied buffer or system MAXPATHLEN
- macOS does not document this (and other) possible errno values
This helps prevent errors related to undefined pointers being passed
through to some OS apis when slices have 0 length.
Tests have also been added to catch these cases.
There are still a few occurrences of "stage1" in the standard library
and self-hosted compiler source, however, these instances need a bit
more careful inspection to ensure no breakage.
This branch largely reverts 58f961f4cb. I
would like to revisit the proposal to modify the standard library in
this way and think more carefully about it before adding isAbsolute()
checks everywhere.
Instead of checking for absolute paths and current working directories
in various file system operations, there is one simple solution: allow
overriding `std.fs.cwd` on WASI.
os.realpath is back to causing a compile error when used on WASI. This
caused a compile error in the Sema handling of `@src()`. The compiler
should never call realpath, so the commit that made this change is
reverted (95ab942184). If this breaks
debug info, a different strategy is needed to solve it other than using
realpath.
I also removed the preopens code and replaced it with something much
simpler. There is no longer any global state in the standard library.
Additionally-
* os.openat no longer does an unnecessary fstat on WASI when O.WRONLY
is not provided.
* os.chdir is back to causing a compile error on WASI.
