Crate libc_abi_tools 

Release-specific libc ABI metadata. Currently supports x86_64 Linux glibc.

Adapted from Zig’s libc ABI tools; see NOTICE.md and LICENSES/Zig-MIT.txt. Collects metadata and emits experimental link-only assembly sources. It supplies no libc runtime implementation; see the qualified example scope.

What it does

• ABI metadata (glibc, matrix): every versioned symbol that each glibc release from 2.17 through 2.44 exports from its eight public libraries (libc, libm, ld, …), read from glibc’s own ABI lists. A Matrix answers whether a link against a release can use name@GLIBC_x.y.
• Link-only stubs (stub, elf, libgcc): assembly and version scripts for shared libraries that define exactly a release’s symbols and versions, with no code. Linking against them fails on anything newer than the release.
• Providers (provider): everything a linker needs to build for one release (headers, startup objects, nonshared archives, stubs), prepared and cached locally in source or container mode, and described by a descriptor that cargo-libc reads.

The libc-abi binary exposes these as commands (libc-abi glibc ..., libc-abi libgcc stub, libc-abi provider ...); run libc-abi --help.

Features

Both are on by default.

• bundled-glibc-data compiles in the GNU C Library’s ABI lists from the glibc-abilists crate (LGPL-2.1-or-later), taken from glibc’s signed release tags. Without it, the data is read from a directory instead (glibc::Snapshot::load, --data DIR).
• provider-sources compiles in the recorded glibc sources of the glibc-provider-sources crate (LGPL-2.1-or-later, and the Linux UAPI headers’ licenses), which source-mode providers compile with the host’s GCC. Without it, only container mode prepares providers.

This crate’s own code is MIT licensed.

Example

Whether a program linked for glibc 2.17 or 2.28 may import memfd_create, which glibc added in 2.27:

use libc_abi_tools::glibc::{Kind, Snapshot};
use libc_abi_tools::matrix::{Expectation, Matrix};
use libc_abi_tools::version::Version;

let v = |text: &str| text.parse::<Version>();
let matrix = Matrix::from_snapshots([
    Snapshot::bundled(v("2.17")?)?,
    Snapshot::bundled(v("2.28")?)?,
])?;
let memfd = |release| matrix.expect(release, "c", "memfd_create", "2.27".parse().unwrap());
assert_eq!(memfd(v("2.17")?), Expectation::Reject);
assert_eq!(memfd(v("2.28")?), Expectation::Accept(Kind::Function));
// A release outside the matrix is unknown, not rejected.
assert_eq!(memfd(v("2.22")?), Expectation::Unknown);

Modules

elf

Bounded ELF64 x86_64 dynamic-symbol evidence. No alias semantics are inferred.

glibc

glibc abilist parsing and collection, derived from Zig’s glibc tools. Copyright (c) Zig contributors; Copyright (c) 2026 rustcommons contributors. SPDX-License-Identifier: MIT

libgcc

The compiler runtime libgcc_s.so.1 as a link-only stub.

matrix

Cross-release public ABI evidence. Snapshot absence is not historical absence.

provider

glibc link providers: everything needed to link x86_64 Linux programs for one glibc release, prepared on the build machine.

stub

Experimental evidence-driven x86_64 link-only assembly, separate from collection. No code, initialized data, IFUNC implementations, or TLS initialization is copied.

version

Numeric versions, used for glibc releases (2.17) and symbol versions (GLIBC_2.2.5 without its prefix).