The fstype argument to the mount system call can be null. To see an
example run "strace -e trace=mount unshare -m":
```
mount("none", "/", NULL, MS_REC|MS_PRIVATE, NULL) = 0
...
```
The previous definition depends on a non-lang-spec-compliant memory
layout for packed structs, which happens to trigger #11989 in stage2.
This commit changes the struct to be an extern struct with an
align(4) field. However, stage1 cannot handle this, so conditional
compilation logic is used to select different struct definitions
depending on stage1 vs stage2.
This works around #11989 but does not solve the underlying problem -
putting an extern union inside a packed struct will still trigger the
assert.
After this, both stage1 and stage2 std lib tests run assertion-clean
with a debug LLVM 13.
This is a prelude to a more elaborate work which will implement
`-dead_strip` flag - garbage collection of unreachable atoms. Here,
when sorting sections, we also check that the section is actually
populated with some atoms, and if not, we exclude it from the final
linked image. This can happen when we do not import any symbols
from dynamic libraries in which case we will not be populating
the stubs sections or the GOT table, implying we can skip allocating
those sections. Furthermore, we also make a check that a segment
is actually occupied too, with the exception of `__TEXT` segment
which is non-optional given that it wraps the header and load commands
and thus is required by the `dyld` to perform dynamic linking, and
`__PAGEZERO` which is generally non-optional when the linked image
is an executable. For any other segment, if its section count is
zero, we mark it as dead and skip allocating it and generating
a load command for it.
This commit also includes some minor improvements to the linker such
as refactoring of the segment allocating codepaths, skipping
`__PAGEZERO` generation for dylibs, and skipping generation of zero-sized
atoms for special symbols such as `__mh_execute_header` and `___dso_handle`.
These special symbols are only allocated local and global symbol pair
and their VM addresses is set to the start of the `__TEXT` segment,
but no `Atom` is created, as it's not necessary given that they never
carry any machine code.
Finally, we now always force-link against `libSystem` which turns out
to be required for `dyld` to properly handle `LC_MAIN` load command
on older macOS versions such as 10.15.7.
Gimli was a game changer. A permutation that is large enough to be
used in sponge-like constructions, yet small enough to be compact
to implement and fast on a wide range of platforms.
And Gimli being part of the Zig standard library was awesome.
But since then, Gimli entered the NIST Lightweight Cryptography
Competition, competing againt other candidates sharing a similar set
of properties.
Unfortunately, Gimli didn't pass the 3rd round.
There are no practical attacks against Gimli when used correctly, but
NIST's decision means that Gimli is unlikely to ever get any traction.
So, maybe the time has come to move Gimli from the standard library
to another repository.
We shouldn't do it without providing an alternative, though.
And the best candidate for this is probably Xoodoo.
Xoodoo is the core function of Xoodyak, one of the finalists of the
NIST LWC competition, and the most direct competitor to Gimli. It is
also a 384-bit permutation, so it can easily be used everywhere Gimli
was used with no parameter changes.
It is the building block of Xoodyak (for actual encryption and hashing)
as well as Charm, that some Zig applications are already using.
Like Gimli that it was heavily inspired from, it is compact and
suitable for constrained environments.
This change adds the Xoodoo permutation to std.crypto.core.
The set of public functions includes everything required to later
implement existing Xoodoo-based constructions.
In order to prepare for the Gimli deprecation, the default
CSPRNG was changed to a Xoodoo-based that works exactly the same way.
A hash function cascade was a common way to avoid length-extension
attacks with traditional hash functions such as the SHA-2 family.
Add `std.crypto.hash.composition` to do exactly that using arbitrary
hash functions, and pre-define the common SHA2-based ones.
With this, we can now sign and verify Bitcoin signatures in pure Zig.
Rather than lowering float negation as `0.0 - x`.
* Add AIR instruction for float negation.
* Add compiler-rt functions for f128, f80 negation
closes#11853
The LLVM backend was calculating the amount of padding solely based
on the payload size. However, in the case where there is no union
tag, this fails to take into account alignment.
Closes#11857
Many of the Managed methods accepted by-val parameters which could
reference Limb slices that became invalid memory after any
ensureCapacity calls. Now, Managed methods accept `*const Managed`
parameters so that if the function allows aliasing and the
ensure-capacity call resizes the Limb slice, it also affects the
aliased parameters, avoiding use-after-free bugs.
This is a breaking change that reduces the requirement for callsites to
manually make the ensure-capacity changes prior to calling many of the
Managed methods.
Closes#11897
std.crypto.ecc: add support for the secp256k1 curve
Usage of the secp256k1 elliptic curve recently grew exponentially,
since this is the curve used by Bitcoin and other popular blockchains
such as Ethereum.
With this, Zig has support for all the widely deployed elliptic curves
today.
* mem: refactor tests of split()
- add a few cases for .rest()
- use expectEqualSlices()
* mem: add splitBackwards
Over the last couple of weeks weeks I needed to iterate over a
collection backwards at least twice. Do we want to have this in stdlib?
If yes, click "Merge" and start using today! Free shipping and returns
(before 1.0).
Why is this useful?
-------------------
I need this for building an error wrapper: errors are added in the
wrapper from "lowest" level to "highest" level, and then printed in
reverse order. Imagine `UpdateUsers` call, which needs to return
`error.InvalidInput` and a wrappable error context. In Go we would add a
context to the error when returning it:
// if update_user fails, add context on which user we are operating
if err := update_user(user); err != nil {
return fmt.Errorf("user id=%d: %w", user.id, err)
}
Since Zig cannot pass anything else than u16 with an error (#2647), I
will pass a `err_ctx: *Err`, to the callers, where they can, besides
returning an error, augment it with auxiliary data. `Err` is a
preallocated array that can add zero-byte-separated strings. For a
concrete example, imagine such a call graph:
update_user(User, *Err) error{InvalidInput}!<...>
validate_user([]const u8, *Err) error{InvalidInput}!<...>
Where `validate_user` would like, besides only the error, signal the
invalid field. And `update_user`, besides the error, would signal the
offending user id.
We also don't want the low-level functions to know in which context they
are operating to construct a meaningful error message: if validation
fails, they append their "context" to the buffer. To translate/augment
the Go example above:
pub fn validate_user(err_ctx: *Err, user: User) error{InvalidInput}!void {
const name = user.name;
if (!ascii.isAlpha(name)) {
err_ctx.print("name '{s}' must be ascii-letters only", .{name});
return error.InvalidInput;
}
<...>
}
// update_user validates each user and does something with it.
pub fn update_user(err_ctx: *Err, user: User) error{InvalidInput}!void {
// validate the user before updating it
validate_user(user) catch {
err_ctx.print("user id={d}", .{user.id});
return error.InvalidInput;
};
<...>
}
Then the top-level function (in my case, CLI) will read the buffer
backwards (splitting on `"\x00"`) and print:
user id=123: name 'Žvangalas' must be ascii-letters only
To read that buffer backwards, dear readers of this commit message, I
need `mem.splitBackwards`.
For 25519, it's very likely that applications would ever need the
serialized representation. Expose the value as an integer as in
other curves. Rename the internal representation from `field_size`
to `field_order` for consistency.
Also fix a common typo in `scalar.sub()`.
This reverts commit 8bf3e1f8d0, which
introduced miscompilations for peer expressions any time they needed
coercions to runtime types.
I opened #11957 as a proposal to accomplish the goal of the reverted
commit.
Closes#11898
Improve testing MachO binaries by verbose printing of the symtab
which includes segment,section names for defined symbols, and
import (dylib) name for imports.
This valid zig code produces reasonable LLVM IR, however, on the
wasm32-wasi target, when using the wasmtime runtime, the number of
locals of the `isSquare` function exceeds 50000, causing wasmtime
to refuse to execute the binary.
The `inline` keyword in Zig is intended to be used only where it is
semantically necessary; not as an optimization hint. Otherwise, this may
produce unwanted binary bloat for the -OReleaseSmall use case.
In the future, it is possible that we may end up with both `inline`
keyword, which operates as it does in status quo, and additionally
`callconv(.inline_hint)` which has no semantic impact, but may be
observed by optimization passes.
In this commit, I also cleaned up `isSquare` by eliminating an
unnecessary mutable variable, replacing it with several local constants.
Closes#11947.
MachO linker now handles `-needed-l<name>`, `-needed_library=<name>`
and `-needed_framework=<name>`. While on macOS `-l` is equivalent
to `-needed-l`, and `-framework` to `-needed_framework`, it can be
used to the same effect as on Linux if combined with `-dead_strip_dylibs`.
This commit also adds handling for `-needed_library` which is macOS
specific flag only (in addition to `-needed-l`).
Finally, in order to leverage new linker testing harness, this commit
added ability to specify lowering to those flags via `build.zig`:
`linkSystemLibraryNeeded` (and related), and `linkFrameworkNeeded`.
Before this commit, the passed in length would always be given to the RtlCaptureStackBackTrace call. Now we always give the length of the actual buffer we're using (the addr_buf_stack size of 32 or the passed in length if it's larger than 32; this matches what the doc comment says the function was meant to be doing as well).
This was causing empty stack traces for things like the GeneralPurposeAllocator leak checking.
Fixes#6687
Includes both traditiona and incremental codepaths with one caveat that
in incremental case, the requested size cannot be smaller than the
default padding size due to prealloc required due to incremental nature
of linking.
Also parse `-headerpad_max_install_names`, however, not actionable just yet -
missing implementation.
Inducing failure but not getting OutOfMemory back is not as much of a problem as never inducing failure when it was expected to be induced, so treating them differently and allowing them to be handled differently by the caller is useful.
For example, the current implementation of `std.HashMapUnmanaged.getOrPutContextAdapted` always tries to grow and then recovers from OutOfMemory by attempting a lookup of an existing key. If this function is used (i.e. from `std.BufMap.putMove`) with `checkAllAllocationFailures`, then we'd have previously triggered `error.NondeterministicMemoryUsage`, but the real cause is that `OutOfMemory` is being recovered from and so the error is being swallowed. The new error allows us to both understand what's happening easier and to catch it and ignore it if we're okay with the code we're testing handling `error.OutOfMemory` without always bubbling it up.
