Introduce libgit-sys, a Rust wrapper crate that allows Rust code to call functions in libgit.a. This initial patch defines build rules and an interface that exposes user agent string getter functions as a proof of concept. This library can be tested with `cargo test`. In later commits, a higher-level library containing a more Rust-friendly interface will be added at `contrib/libgit-rs`. Symbols in libgit can collide with symbols from other libraries such as libgit2. We avoid this by first exposing library symbols in public_symbol_export.[ch]. These symbols are prepended with "libgit_" to avoid collisions and set to visible using a visibility pragma. In build.rs, Rust builds contrib/libgit-rs/libgit-sys/libgitpub.a, which also contains libgit.a and other dependent libraries, with -fvisibility=hidden to hide all symbols within those libraries that haven't been exposed with a visibility pragma. Co-authored-by: Kyle Lippincott <spectral@xxxxxxxxxx> Co-authored-by: Calvin Wan <calvinwan@xxxxxxxxxx> Signed-off-by: Calvin Wan <calvinwan@xxxxxxxxxx> Signed-off-by: Kyle Lippincott <spectral@xxxxxxxxxx> Signed-off-by: Josh Steadmon <steadmon@xxxxxxxxxx> --- .gitignore | 1 + Makefile | 48 ++++++++++++++++ contrib/libgit-sys/Cargo.lock | 69 +++++++++++++++++++++++ contrib/libgit-sys/Cargo.toml | 19 +++++++ contrib/libgit-sys/README.md | 4 ++ contrib/libgit-sys/build.rs | 35 ++++++++++++ contrib/libgit-sys/public_symbol_export.c | 23 ++++++++ contrib/libgit-sys/public_symbol_export.h | 8 +++ contrib/libgit-sys/src/lib.rs | 46 +++++++++++++++ t/Makefile | 10 ++++ 10 files changed, 263 insertions(+) create mode 100644 contrib/libgit-sys/Cargo.lock create mode 100644 contrib/libgit-sys/Cargo.toml create mode 100644 contrib/libgit-sys/README.md create mode 100644 contrib/libgit-sys/build.rs create mode 100644 contrib/libgit-sys/public_symbol_export.c create mode 100644 contrib/libgit-sys/public_symbol_export.h create mode 100644 contrib/libgit-sys/src/lib.rs diff --git a/.gitignore b/.gitignore index e82aa19df0..31d7e64287 100644 --- a/.gitignore +++ b/.gitignore @@ -250,3 +250,4 @@ Release/ /git.VC.db *.dSYM /contrib/buildsystems/out +/contrib/libgit-sys/target diff --git a/Makefile b/Makefile index 27e68ac039..a772bff186 100644 --- a/Makefile +++ b/Makefile @@ -416,6 +416,9 @@ include shared.mak # Define LINK_FUZZ_PROGRAMS if you want `make all` to also build the fuzz test # programs in oss-fuzz/. # +# Define INCLUDE_LIBGIT_RS if you want `make all` and `make test` to build and +# test the Rust crate in contrib/libgit-sys. +# # === Optional library: libintl === # # Define NO_GETTEXT if you don't want Git output to be translated. @@ -657,6 +660,8 @@ CURL_CONFIG = curl-config GCOV = gcov STRIP = strip SPATCH = spatch +LD = ld +OBJCOPY = objcopy export TCL_PATH TCLTK_PATH @@ -2236,6 +2241,12 @@ ifdef FSMONITOR_OS_SETTINGS COMPAT_OBJS += compat/fsmonitor/fsm-path-utils-$(FSMONITOR_OS_SETTINGS).o endif +ifdef INCLUDE_LIBGIT_RS + # Enable symbol hiding in contrib/libgit-sys/libgitpub.a without making + # us rebuild the whole tree every time we run a Rust build. + BASIC_CFLAGS += -fvisibility=hidden +endif + ifeq ($(TCLTK_PATH),) NO_TCLTK = NoThanks endif @@ -2732,6 +2743,10 @@ OBJECTS += $(UNIT_TEST_OBJS) OBJECTS += $(CLAR_TEST_OBJS) OBJECTS += $(patsubst %,$(UNIT_TEST_DIR)/%.o,$(UNIT_TEST_PROGRAMS)) +ifdef INCLUDE_LIBGIT_RS + OBJECTS += contrib/libgit-sys/public_symbol_export.o +endif + ifndef NO_CURL OBJECTS += http.o http-walker.o remote-curl.o endif @@ -3726,6 +3741,10 @@ clean: profile-clean coverage-clean cocciclean $(RM) $(htmldocs).tar.gz $(manpages).tar.gz $(MAKE) -C Documentation/ clean $(RM) Documentation/GIT-EXCLUDED-PROGRAMS + $(RM) -r contrib/libgit-sys/target + $(RM) contrib/libgit-sys/partial_symbol_export.o + $(RM) contrib/libgit-sys/hidden_symbol_export.o + $(RM) contrib/libgit-sys/libgitpub.a ifndef NO_PERL $(RM) -r perl/build/ endif @@ -3887,3 +3906,32 @@ $(CLAR_TEST_PROG): $(UNIT_TEST_DIR)/clar.suite $(CLAR_TEST_OBJS) $(GITLIBS) GIT- build-unit-tests: $(UNIT_TEST_PROGS) $(CLAR_TEST_PROG) unit-tests: $(UNIT_TEST_PROGS) $(CLAR_TEST_PROG) t/helper/test-tool$X $(MAKE) -C t/ unit-tests + +.PHONY: libgit-sys +libgit-sys: + $(QUIET)(\ + cd contrib/libgit-sys && \ + cargo build \ + ) +ifdef INCLUDE_LIBGIT_RS +all:: libgit-sys +endif + +LIBGIT_PUB_OBJS = +LIBGIT_PUB_OBJS += contrib/libgit-sys/public_symbol_export.o +LIBGIT_PUB_OBJS += libgit.a +LIBGIT_PUB_OBJS += reftable/libreftable.a +LIBGIT_PUB_OBJS += xdiff/lib.a + +LIBGIT_PARTIAL_EXPORT = contrib/libgit-sys/partial_symbol_export.o + +LIBGIT_HIDDEN_EXPORT = contrib/libgit-sys/hidden_symbol_export.o + +$(LIBGIT_PARTIAL_EXPORT): $(LIBGIT_PUB_OBJS) + $(LD) -r $^ -o $@ + +$(LIBGIT_HIDDEN_EXPORT): $(LIBGIT_PARTIAL_EXPORT) + $(OBJCOPY) --localize-hidden $^ $@ + +contrib/libgit-sys/libgitpub.a: $(LIBGIT_HIDDEN_EXPORT) + $(AR) $(ARFLAGS) $@ $^ diff --git a/contrib/libgit-sys/Cargo.lock b/contrib/libgit-sys/Cargo.lock new file mode 100644 index 0000000000..427a4c66b7 --- /dev/null +++ b/contrib/libgit-sys/Cargo.lock @@ -0,0 +1,69 @@ +# This file is automatically @generated by Cargo. +# It is not intended for manual editing. +version = 3 + +[[package]] +name = "autocfg" +version = "1.4.0" +source = "registry+https://github.com/rust-lang/crates.io-index"; +checksum = "ace50bade8e6234aa140d9a2f552bbee1db4d353f69b8217bc503490fc1a9f26" + +[[package]] +name = "cc" +version = "1.1.15" +source = "registry+https://github.com/rust-lang/crates.io-index"; +checksum = "57b6a275aa2903740dc87da01c62040406b8812552e97129a63ea8850a17c6e6" +dependencies = [ + "shlex", +] + +[[package]] +name = "libc" +version = "0.2.158" +source = "registry+https://github.com/rust-lang/crates.io-index"; +checksum = "d8adc4bb1803a324070e64a98ae98f38934d91957a99cfb3a43dcbc01bc56439" + +[[package]] +name = "libgit-sys" +version = "0.1.0" +dependencies = [ + "autocfg", + "libz-sys", + "make-cmd", +] + +[[package]] +name = "libz-sys" +version = "1.1.20" +source = "registry+https://github.com/rust-lang/crates.io-index"; +checksum = "d2d16453e800a8cf6dd2fc3eb4bc99b786a9b90c663b8559a5b1a041bf89e472" +dependencies = [ + "cc", + "libc", + "pkg-config", + "vcpkg", +] + +[[package]] +name = "make-cmd" +version = "0.1.0" +source = "registry+https://github.com/rust-lang/crates.io-index"; +checksum = "a8ca8afbe8af1785e09636acb5a41e08a765f5f0340568716c18a8700ba3c0d3" + +[[package]] +name = "pkg-config" +version = "0.3.30" +source = "registry+https://github.com/rust-lang/crates.io-index"; +checksum = "d231b230927b5e4ad203db57bbcbee2802f6bce620b1e4a9024a07d94e2907ec" + +[[package]] +name = "shlex" +version = "1.3.0" +source = "registry+https://github.com/rust-lang/crates.io-index"; +checksum = "0fda2ff0d084019ba4d7c6f371c95d8fd75ce3524c3cb8fb653a3023f6323e64" + +[[package]] +name = "vcpkg" +version = "0.2.15" +source = "registry+https://github.com/rust-lang/crates.io-index"; +checksum = "accd4ea62f7bb7a82fe23066fb0957d48ef677f6eeb8215f372f52e48bb32426" diff --git a/contrib/libgit-sys/Cargo.toml b/contrib/libgit-sys/Cargo.toml new file mode 100644 index 0000000000..e0623022c3 --- /dev/null +++ b/contrib/libgit-sys/Cargo.toml @@ -0,0 +1,19 @@ +[package] +name = "libgit-sys" +version = "0.1.0" +edition = "2021" +build = "build.rs" +links = "gitpub" +rust-version = "1.63" # TODO: Once we hit 1.84 or newer, we may want to remove Cargo.lock from + # version control. See https://lore.kernel.org/git/Z47jgK-oMjFRSslr@xxxxxxxxxxxxxxxxxxxxxxxxxxxx/ +description = "Native bindings to a portion of libgit" + +[lib] +path = "src/lib.rs" + +[dependencies] +libz-sys = "1.1.19" + +[build-dependencies] +autocfg = "1.4.0" +make-cmd = "0.1.0" diff --git a/contrib/libgit-sys/README.md b/contrib/libgit-sys/README.md new file mode 100644 index 0000000000..c061cfcaf5 --- /dev/null +++ b/contrib/libgit-sys/README.md @@ -0,0 +1,4 @@ +# libgit-sys + +A small proof-of-concept crate showing how to provide a Rust FFI to Git +internals. diff --git a/contrib/libgit-sys/build.rs b/contrib/libgit-sys/build.rs new file mode 100644 index 0000000000..3ffd80ad91 --- /dev/null +++ b/contrib/libgit-sys/build.rs @@ -0,0 +1,35 @@ +use std::env; +use std::path::PathBuf; + +pub fn main() -> std::io::Result<()> { + let ac = autocfg::new(); + ac.emit_has_path("std::ffi::c_char"); + + let crate_root = PathBuf::from(env::var_os("CARGO_MANIFEST_DIR").unwrap()); + let git_root = crate_root.join("../.."); + let dst = PathBuf::from(env::var_os("OUT_DIR").unwrap()); + + let make_output = make_cmd::gnu_make() + .env("DEVELOPER", "1") + .env_remove("PROFILE") + .current_dir(git_root.clone()) + .args([ + "INCLUDE_LIBGIT_RS=YesPlease", + "contrib/libgit-sys/libgitpub.a", + ]) + .output() + .expect("Make failed to run"); + if !make_output.status.success() { + panic!( + "Make failed:\n stdout = {}\n stderr = {}\n", + String::from_utf8(make_output.stdout).unwrap(), + String::from_utf8(make_output.stderr).unwrap() + ); + } + std::fs::copy(crate_root.join("libgitpub.a"), dst.join("libgitpub.a"))?; + println!("cargo:rustc-link-search=native={}", dst.display()); + println!("cargo:rustc-link-lib=gitpub"); + println!("cargo:rerun-if-changed={}", git_root.display()); + + Ok(()) +} diff --git a/contrib/libgit-sys/public_symbol_export.c b/contrib/libgit-sys/public_symbol_export.c new file mode 100644 index 0000000000..4c153c6f0d --- /dev/null +++ b/contrib/libgit-sys/public_symbol_export.c @@ -0,0 +1,23 @@ +/* + * Shim to publicly export Git symbols. These must be renamed so that the + * original symbols can be hidden. Renaming these with a "libgit_" prefix also + * avoids conflicts with other libraries such as libgit2. + */ + +#include "git-compat-util.h" +#include "contrib/libgit-sys/public_symbol_export.h" +#include "version.h" + +#pragma GCC visibility push(default) + +const char *libgit_user_agent(void) +{ + return git_user_agent(); +} + +const char *libgit_user_agent_sanitized(void) +{ + return git_user_agent_sanitized(); +} + +#pragma GCC visibility pop diff --git a/contrib/libgit-sys/public_symbol_export.h b/contrib/libgit-sys/public_symbol_export.h new file mode 100644 index 0000000000..a3372f93fa --- /dev/null +++ b/contrib/libgit-sys/public_symbol_export.h @@ -0,0 +1,8 @@ +#ifndef PUBLIC_SYMBOL_EXPORT_H +#define PUBLIC_SYMBOL_EXPORT_H + +const char *libgit_user_agent(void); + +const char *libgit_user_agent_sanitized(void); + +#endif /* PUBLIC_SYMBOL_EXPORT_H */ diff --git a/contrib/libgit-sys/src/lib.rs b/contrib/libgit-sys/src/lib.rs new file mode 100644 index 0000000000..d4853f3074 --- /dev/null +++ b/contrib/libgit-sys/src/lib.rs @@ -0,0 +1,46 @@ +#[cfg(has_std__ffi__c_char)] +use std::ffi::c_char; + +#[cfg(not(has_std__ffi__c_char))] +#[allow(non_camel_case_types)] +pub type c_char = i8; + +extern crate libz_sys; + +extern "C" { + pub fn libgit_user_agent() -> *const c_char; + pub fn libgit_user_agent_sanitized() -> *const c_char; +} + +#[cfg(test)] +mod tests { + use std::ffi::CStr; + + use super::*; + + #[test] + fn user_agent_starts_with_git() { + let c_str = unsafe { CStr::from_ptr(libgit_user_agent()) }; + let agent = c_str + .to_str() + .expect("User agent contains invalid UTF-8 data"); + assert!( + agent.starts_with("git/"), + r#"Expected user agent to start with "git/", got: {}"#, + agent + ); + } + + #[test] + fn sanitized_user_agent_starts_with_git() { + let c_str = unsafe { CStr::from_ptr(libgit_user_agent_sanitized()) }; + let agent = c_str + .to_str() + .expect("Sanitized user agent contains invalid UTF-8 data"); + assert!( + agent.starts_with("git/"), + r#"Expected user agent to start with "git/", got: {}"#, + agent + ); + } +} diff --git a/t/Makefile b/t/Makefile index daa5fcae86..53ba01c21b 100644 --- a/t/Makefile +++ b/t/Makefile @@ -177,3 +177,13 @@ perf: .PHONY: pre-clean $(T) aggregate-results clean valgrind perf \ check-chainlint clean-chainlint test-chainlint $(UNIT_TESTS) + +.PHONY: libgit-sys-test +libgit-sys-test: + $(QUIET)(\ + cd ../contrib/libgit-sys && \ + cargo test \ + ) +ifdef INCLUDE_LIBGIT_RS +all:: libgit-sys-test +endif -- 2.48.1.362.g079036d154-goog
