v5 link failure

[PaulDance]

Hi,

I have tried upgrading our project to using v5, however in doing so, the following weird linker error occurs:

error: linking with `/nix/store/81nnwpxsmjzkwxqzjpbkazlw2gbhgi44-x86_64-unknown-linux-musl-gcc-wrapper-15.2.0/bin/x86_64-unknown-linux-musl-gcc` failed: exit status: 1
  |
  = note:  "/nix/store/81nnwpxsmjzkwxqzjpbkazlw2gbhgi44-x86_64-unknown-linux-musl-gcc-wrapper-15.2.0/bin/x86_64-unknown-linux-musl-gcc" "-m64" "<sysroot>/lib/rustlib/x86_64-unknown-linux-musl/lib/self-contained/rcrt1.o" "<sysroot>/lib/rustlib/x86_64-unknown-linux-musl/lib/self-contained/crti.o" "<sysroot>/lib/rustlib/x86_64-unknown-linux-musl/lib/self-contained/crtbeginS.o" "[...]/target/x86_64-unknown-linux-musl/release/deps/rustc8ziHQe/symbols.o" "<17 object files omitted>" "-Wl,--as-needed" "-Wl,-Bstatic" "[...]/target/x86_64-unknown-linux-musl/release/deps/{libconfig-6c9c61896e37df33,libpathdiff-d296a2564e31c710,libtoml-5499fdf896ea29a6,libtoml_edit-b15c59c496944696,libserde_spanned-e7b8570be1dec9cf,libtoml_datetime-703e075eed47db1c,libwinnow-c3500c1e322eb6c8,libargh-f34ea2d771731614,libargh_shared-55d097bfddb0bafc,libhl_communication-458aebe4d069e162,libhl_constants-be2c10a8e34deddf,libhyper_rustls-9cdc3875776abf58,librustls_native_certs-6a9a2c85cf7c4fa5,libopenssl_probe-664548dfaa217477,libhl_param-bb217314ce1a2038,libhl_agent_structs-6f4aa882f0a196be,libhl_impersonation-9fa394effc78d9f7,libhl_ebpf-7eabcf42c2be7d9e,libhl_system-398b8b84d2ff8722,libtar-0e46d6850391da5f,libxattr-f991ce681e90f1a7,librustix-134aff22a666f5a3,liblinux_raw_sys-8f7bc80368864d49,libfiletime-22f7582ad758230e,librayon-aaf24e31f9e1a000,librayon_core-14e2c83f96c33770,libcrossbeam_deque-370f348e4428a83a,libcrossbeam_epoch-423db33bfd5386b9,libcrossbeam_utils-c0daa9425a54f9df,liblzma_rs-c5a0f382d438820e,libcrc-82660040bb014a69,libcrc_catalog-393aefc015291c52,libhl_ebpf_sys-f5f84879c8c2c7cc,libaya-bf989626c49bbdf6,libassert_matches-cdd6a1e7fa78843d,libaya_obj-c47a5b76182ee3c2,libhl_proc_startid-e44b31922e945a36,libhl_agent_store-2347ca56ea224372,libhl_store-e7b4c258f5146fbc,libtempfile-cbf0d096231ed048,libfastrand-abb5b34f7a140781,librustix-29df0f35a0bc7dc0,liblinux_raw_sys-74a2f6f8f0b9f37b,librusqlite-ebff6efb0ab4b450,libhashlink-eb31138831655315,libhashbrown-4ed33a2817e17769,libfoldhash-ff9fdc7bfa791472,liblibsqlite3_sys-6d9cedd3b8b78732,libfallible_streaming_iterator-7d2f507d46ba79d1,libfallible_iterator-453a9395dd916412,libhyper_proxy2-edc5de49248b943c,libheaders-1ad506e15fc684ae,libsha1-703c2501812f4058,libheaders_core-c7c99d74e6b7de60,libbase64-836ecaa8d9f7986c,libhyper_boring-d3dec3b177bd7c1d,libtower-5475b8a90619448b,libantidote-a0e845d5554f20ab,liblinked_hash_set-83992cd2d1f5eae1,liblinked_hash_map-d978f9d0a552b6d5,libtokio_boring-acf6ef0a4570001f,libhl_directories-612d12322bc5b045,libhl_proto-be8ef51b783a90e3,libhl_tracing-baad3f0a52ab988f,libhl_version-653f382f9e4f6eee,libhl_fs-2ed07b373e3fc962,libthiserror-6537a22496b5a387,libhl_osstr-3c58760fb8f19e10,libunicase-a455074fc8fdfeed,libsentry_contrib_breakpad-bfa9d8dd4e6798f3,libbreakpad_handler-090482ea7073543c,libbreakpad_sys-e0b826481cb2fd04,libsentry-ee6b5c1c727a7207,libsentry_tracing-48418171fdd29337,libtracing_subscriber-df743c24b0ff3bac,libthread_local-91d2f00244ca3b2a,libsharded_slab-970792f208f7d931,liblazy_static-0c19ad66d34022f7,libtracing_log-e9f99676196505b7,libsentry_debug_images-cd9e42e4782a071c,libfindshlibs-9ea7ad68ada7f54b,libsentry_backtrace-16f78ee9d745dcbe,libbacktrace-a23e05be5add35bc,libminiz_oxide-daa3e842617ed774,libsimd_adler32-d798e5046c9d67ed,libobject-eb93b7560cdbe2f5,libcrc32fast-b6f494f7d56ec935,libruzstd-91d24e6b539d931f,libtwox_hash-3ad1c754712c1960,libflate2-35c2202d6acc3518,libzlib_rs-3a6398feb920ce4d,libaddr2line-6a6cf4cb69c67afb,libgimli-7c57377820235d7c,librustc_demangle-5a782d75254542a1,libsentry_core-548c4fc062882209,libsentry_types-dd3372caf3e32241,librand-754b53d5b6a249b4,librand_chacha-5a621ccb8aad8727,libdebugid-5326791d3fcbc0c4,libserde_json-26f12199ca8e1ac9,libzmij-851da6fade3243a7,liburl-7f1d31f69410f71e,libidna-146e14df9a3fabf7,libidna_adapter-c2e55cf5c2ed503d,libicu_normalizer-e784c3bae70228b8,libicu_normalizer_data-51f042f8434c682c,libwrite16-fb8e7b1f0188569e,libutf8_iter-ec948cdfe0b86125,libutf16_iter-0047e84abac9fe00,libicu_properties-e24b7da4ee4fe140,libicu_properties_data-5a0cf05593598062,libicu_locid_transform-0015e05506d6dfe0,libicu_locid_transform_data-12b674b3f61a5b73,libicu_collections-7ef223ff6d8a3ba2,libicu_provider-f36f3b57c1dff0d1,libicu_locid-893135866d54c720,liblitemap-8cfe6d0ceaac5ba0,libtinystr-ed659b0588f43c19,libzerovec-7578cb3b00a4874b,libwriteable-d63639fe5e25a895,libyoke-a59b92a6560bef0e,libzerofrom-5072dfa0f7c8a429,libstable_deref_trait-0e6e3fe0faf2792e,libform_urlencoded-31ef38fd915a6afd,libbrotli-673306de26b3a0ed,libbrotli_decompressor-6dab6870a3f532bc,liballoc_stdlib-fe720fe0ad96ac47,liballoc_no_stdlib-d925fcb40ff72a6a,libstatic_assertions-26b86fa2e40e2092,libhl_proto_types-6aec127cca482069,libhl_time-3aeeccf6f8292790,libpbjson_types-db6e4d9b00c8e65b,libpbjson-b9b767add219b3d6,libtime-dcc3265fd73e61e9,libnum_threads-ab7656e42d309200,libtime_core-eb6fb2d02a5c8296,libnum_conv-a25b7ed5e8e420cc,libderanged-fd78b508b7b433cb,libpowerfmt-829fc4f20df77ce8,libstrum-beea48756fda624a,libregex-b479ff3779759d30,libregex_automata-32547bd3b4328625,libaho_corasick-713f78e913d65363,libregex_syntax-84062a3eb3b6da48,libitertools-039fa175567cccda,libeither-b2ba9cca3b179076,libhex_literal-24c021e28e02f270,libhl_interner-b1f9a134e4d297a1,libscc-59a58e1d59973db9,libsaa-8c322e5b31d57658,libsdd-c562db4af8f79bb6,liblz4_flex-ba37836c4f7f6a85,libtwox_hash-385b2d7a7ff94d63,libchacha20poly1305-157abccca8db253c,libpoly1305-b853f41342e1f9d4,libaes_gcm-c3a8b40183c12f77,libctr-b01555cb50690feb,libghash-cd9f4ff4b26c2a56,libpolyval-23f490e06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"<sysroot>/lib/rustlib/x86_64-unknown-linux-musl/lib/{libstd-*,libpanic_unwind-*,libobject-*,libmemchr-*,libaddr2line-*,libgimli-*,libcfg_if-*,librustc_demangle-*,libstd_detect-*,libhashbrown-*,librustc_std_workspace_alloc-*,libminiz_oxide-*,libadler2-*,libunwind-*}.rlib" "-lunwind" "<sysroot>/lib/rustlib/x86_64-unknown-linux-musl/lib/liblibc-*.rlib" "-lc" "<sysroot>/lib/rustlib/x86_64-unknown-linux-musl/lib/{librustc_std_workspace_core-*,liballoc-*,libcore-*,libcompiler_builtins-*}.rlib" "-Wl,-Bdynamic" "-lstdc++" "-L" "[...]/target/x86_64-unknown-linux-musl/release/deps/rustc8ziHQe/raw-dylibs" "-Wl,--eh-frame-hdr" "-Wl,-z,noexecstack" "-nostartfiles" "-L" "/nix/store/m4jki8j89n6r261n5wm9z18kznw5gmby-x86_64-unknown-linux-musl-gcc-15.2.0/x86_64-unknown-linux-musl/lib" "-L" "/nix/store/rv4c31ryip8azhh98l4gvvxrfznwbssk-musl-x86_64-unknown-linux-musl-1.2.5/lib" "-L" "[...]/target/x86_64-unknown-linux-musl/release/build/boring-sys-5816a72ee9985233/out/build/lib" "-L" "[...]/target/x86_64-unknown-linux-musl/release/build/boring-sys-5816a72ee9985233/out/build/crypto" "-L" "[...]/target/x86_64-unknown-linux-musl/release/build/boring-sys-5816a72ee9985233/out/build/ssl" "-L" "[...]/target/x86_64-unknown-linux-musl/release/build/boring-sys-5816a72ee9985233/out/build/" "-L" "[...]/target/x86_64-unknown-linux-musl/release/build/breakpad-sys-91b882c2d5c344c2/out" "-L" "[...]/target/x86_64-unknown-linux-musl/release/build/ring-2b161cea703e5b44/out" "-L" "[...]/target/x86_64-unknown-linux-musl/release/build/libsqlite3-sys-680082211d0e98ab/out" "-L" "<sysroot>/lib/rustlib/x86_64-unknown-linux-musl/lib/self-contained" "-L" "<sysroot>/lib/rustlib/x86_64-unknown-linux-musl/lib" "-o" "[...]/target/x86_64-unknown-linux-musl/release/deps/back_stress-52f811b27afc7ddb" "-Wl,--gc-sections" "-static-pie" "-Wl,-z,relro,-z,now" "-Wl,-O1" "-nodefaultlibs" "-Wl,--build-id=sha1" "<sysroot>/lib/rustlib/x86_64-unknown-linux-musl/lib/self-contained/crtendS.o" "<sysroot>/lib/rustlib/x86_64-unknown-linux-musl/lib/self-contained/crtn.o"
  = note: some arguments are omitted. use `--verbose` to show all linker arguments
  = note: /nix/store/ghh9ph8sxhxmd908na3njl3sbmpnffn3-x86_64-unknown-linux-musl-binutils-2.44/bin/x86_64-unknown-linux-musl-ld: /nix/store/m4jki8j89n6r261n5wm9z18kznw5gmby-x86_64-unknown-linux-musl-gcc-15.2.0/x86_64-unknown-linux-musl/lib/libstdc++.a(cp-demangle.o): in function `d_append_num':
          (.text+0x9cc): undefined reference to `sprintf'
          /nix/store/ghh9ph8sxhxmd908na3njl3sbmpnffn3-x86_64-unknown-linux-musl-binutils-2.44/bin/x86_64-unknown-linux-musl-ld: /nix/store/m4jki8j89n6r261n5wm9z18kznw5gmby-x86_64-unknown-linux-musl-gcc-15.2.0/x86_64-unknown-linux-musl/lib/libstdc++.a(cp-demangle.o): in function `d_print_lambda_parm_name':
          (.text+0xada): undefined reference to `sprintf'
          /nix/store/ghh9ph8sxhxmd908na3njl3sbmpnffn3-x86_64-unknown-linux-musl-binutils-2.44/bin/x86_64-unknown-linux-musl-ld: /nix/store/m4jki8j89n6r261n5wm9z18kznw5gmby-x86_64-unknown-linux-musl-gcc-15.2.0/x86_64-unknown-linux-musl/lib/libstdc++.a(cp-demangle.o): in function `d_type':
          (.text+0x15e7): undefined reference to `sprintf'
          /nix/store/ghh9ph8sxhxmd908na3njl3sbmpnffn3-x86_64-unknown-linux-musl-binutils-2.44/bin/x86_64-unknown-linux-musl-ld: /nix/store/m4jki8j89n6r261n5wm9z18kznw5gmby-x86_64-unknown-linux-musl-gcc-15.2.0/x86_64-unknown-linux-musl/lib/libstdc++.a(cp-demangle.o): in function `d_print_comp_inner':
          (.text+0x5730): undefined reference to `sprintf'
          /nix/store/ghh9ph8sxhxmd908na3njl3sbmpnffn3-x86_64-unknown-linux-musl-binutils-2.44/bin/x86_64-unknown-linux-musl-ld: (.text+0x7683): undefined reference to `sprintf'
          /nix/store/ghh9ph8sxhxmd908na3njl3sbmpnffn3-x86_64-unknown-linux-musl-binutils-2.44/bin/x86_64-unknown-linux-musl-ld: /nix/store/m4jki8j89n6r261n5wm9z18kznw5gmby-x86_64-unknown-linux-musl-gcc-15.2.0/x86_64-unknown-linux-musl/lib/libstdc++.a(cp-demangle.o):(.text+0x786b): more undefined references to `sprintf' follow
          /nix/store/ghh9ph8sxhxmd908na3njl3sbmpnffn3-x86_64-unknown-linux-musl-binutils-2.44/bin/x86_64-unknown-linux-musl-ld: /nix/store/m4jki8j89n6r261n5wm9z18kznw5gmby-x86_64-unknown-linux-musl-gcc-15.2.0/x86_64-unknown-linux-musl/lib/libstdc++.a(eh_alloc.o): in function `_GLOBAL__sub_I_eh_alloc.cc':
          (.text.startup._GLOBAL__sub_I_eh_alloc.cc+0x4b): undefined reference to `secure_getenv'
          collect2: error: ld returned 1 exit status
          
  = note: some `extern` functions couldn't be found; some native libraries may need to be installed or have their path specified
  = note: use the `-l` flag to specify native libraries to link
  = note: use the `cargo:rustc-link-lib` directive to specify the native libraries to link with Cargo (see https://doc.rust-lang.org/cargo/reference/build-scripts.html#rustc-link-lib)

It occurs specifically for x86_64-unknown-linux-musl and no other target (three Windows ones and two macOS ones). Also, for some odd reason, I can't yet seem to be able to reproduce the error locally, only in CI for now. We use Nix in order to bring much of the build dependencies in. We use MUSL-GCC as both the C/C++ compiler and linker for this target.

I see that the contents of the boring-sys/deps/boringssl/ directory have changed quite a bit between v4 and v5: could there have been some breakage there somehow? Most of the build tooling is up-to-date on our side as far as I can tell.

[kornelski]

Google's Boring is a C++ library, and one of the annoying problems about C++ is fragmentation of standard library implementations.

We're setting GNU C++ on GNU targets, but by Rust's standards MUSL is a non-GNU target. You're mixing it up in a way that breaks it.

If your setup is detectable, you can fix the logic here:

boring/boring-sys/build/main.rs

Lines 578 to 589 in 3921f35

	fn get_cpp_runtime_lib(config: &Config) -> Option<String> {
	if let Some(ref cpp_lib) = config.env.cpp_runtime_lib {
	return cpp_lib.clone().into_string().ok();
	}
	match &*config.target_os {
	"macos" | "ios" | "freebsd" | "openbsd" | "android" => Some("c++".into()),
	_ if config.unix || config.target_env == "gnu" => Some("stdc++".into()),
	// TODO(rmehra): figure out how to do this for windows
	_ => None,
	}
	}

[PaulDance]

Thanks for the details. I have fiddled with this part a bit, and what I don't understand is that stdc++ is gated also by config.unix that is true, so the link instruction should already be correct:

[boring-sys 5.1.0] [/home/pauldance/.cargo/git/checkouts/boring-bc9c8098345c7ec3/6eded74/boring-sys/build/main.rs:598:5] `&config` = Config {
[boring-sys 5.1.0]     manifest_dir: "/home/pauldance/.cargo/git/checkouts/boring-bc9c8098345c7ec3/6eded74/boring-sys",
[boring-sys 5.1.0]     out_dir: "/home/pauldance/git/[...]/target/x86_64-unknown-linux-musl/release/build/boring-sys-3ebe81905640c144/out",
[boring-sys 5.1.0]     is_bazel: false,
[boring-sys 5.1.0]     host: "x86_64-unknown-linux-gnu",
[boring-sys 5.1.0]     target: "x86_64-unknown-linux-musl",
[boring-sys 5.1.0]     target_arch: "x86_64",
[boring-sys 5.1.0]     target_os: "linux",
[boring-sys 5.1.0]     unix: true,
[boring-sys 5.1.0]     target_env: "musl",
[boring-sys 5.1.0]     target_features: [
[boring-sys 5.1.0]         "fxsr",
[boring-sys 5.1.0]         "sse",
[boring-sys 5.1.0]         "sse2",
[boring-sys 5.1.0]         "x87",
[boring-sys 5.1.0]     ],
[boring-sys 5.1.0]     features: Features {
[boring-sys 5.1.0]         fips: false,
[boring-sys 5.1.0]         rpk: false,
[boring-sys 5.1.0]         underscore_wildcards: false,
[boring-sys 5.1.0]     },
[boring-sys 5.1.0]     env: Env {
[boring-sys 5.1.0]         path: None,
[boring-sys 5.1.0]         include_path: None,
[boring-sys 5.1.0]         source_path: None,
[boring-sys 5.1.0]         assume_patched: false,
[boring-sys 5.1.0]         sysroot: None,
[boring-sys 5.1.0]         compiler_external_toolchain: None,
[boring-sys 5.1.0]         debug: Some(
[boring-sys 5.1.0]             "false",
[boring-sys 5.1.0]         ),
[boring-sys 5.1.0]         opt_level: Some(
[boring-sys 5.1.0]             "3",
[boring-sys 5.1.0]         ),
[boring-sys 5.1.0]         android_ndk_home: None,
[boring-sys 5.1.0]         cmake_toolchain_file: Some(
[boring-sys 5.1.0]             "/nix/store/r2xnrkhv56qy638j0qc9i2izlrsihbf5-musl.x64.cmake",
[boring-sys 5.1.0]         ),
[boring-sys 5.1.0]         cpp_runtime_lib: None,
[boring-sys 5.1.0]         cc: Some(
[boring-sys 5.1.0]             "/nix/store/s65clklw6q6kjhkgcpgva0r8big3z7rh-sccache-0.14.0/bin/sccache /nix/store/81nnwpxsmjzkwxqzjpbkazlw2gbhgi44-x86_64-unknown-linux-musl-gcc-wrapper-15.2.0/bin/x86_64-unknown-linux-musl-gcc",
[boring-sys 5.1.0]         ),
[boring-sys 5.1.0]         cxx: Some(
[boring-sys 5.1.0]             "/nix/store/s65clklw6q6kjhkgcpgva0r8big3z7rh-sccache-0.14.0/bin/sccache /nix/store/81nnwpxsmjzkwxqzjpbkazlw2gbhgi44-x86_64-unknown-linux-musl-gcc-wrapper-15.2.0/bin/x86_64-unknown-linux-musl-g++",
[boring-sys 5.1.0]         ),
[boring-sys 5.1.0]         docs_rs: false,
[boring-sys 5.1.0]         export_to_install_dir: None,
[boring-sys 5.1.0]     },
[boring-sys 5.1.0] }
[boring-sys 5.1.0] [/home/pauldance/.cargo/git/checkouts/boring-bc9c8098345c7ec3/6eded74/boring-sys/build/main.rs:698:28] `get_cpp_runtime_lib(config)` = Some(
[boring-sys 5.1.0]     "stdc++",
[boring-sys 5.1.0] )
[boring-sys 5.1.0] cargo:rustc-link-lib=stdc++
[boring-sys 5.1.0] cargo:rustc-link-lib=static=crypto
[boring-sys 5.1.0] cargo:rustc-link-lib=static=ssl

can already be observed in the build output if I add some debug logging in it, and without having to modify the logic you point to. Also, from what I can see, this logic hasn't changed much recently with regards to UNIX target environments, and v4 has no such issue under the same build environment that already sets various library search paths and such, so why does v5 break in this aspect?

Also note the link arguments in the original error: -L "/nix/store/m4jki8j89n6r261n5wm9z18kznw5gmby-x86_64-unknown-linux-musl-gcc-15.2.0/x86_64-unknown-linux-musl/lib" that indeed contains a libstdc++.a.

[kornelski]

It looks like you're on a GNU host and you're cross-compiling to a MUSL target.

I have no idea how MUSL-GCC is going to play with that.

This is not an issue of having the other C++ library available, but a much harder problem of ensuring that absolutely nothing contaminates the build with a second conflicting C++ runtime.

Does Rust even work with that given that it assumes MUSL is an LLVM target? Are you configuring the linker for Rust to stop it from using built-in lld? Have you ensured that CMake doesn't auto detect MUSL toolchain and use LLVM tooling for it?

Have you got a dedicated sysroot and redirected pkg-config for the MUSL-GCC target OS? or are you relying on the build never touching anything from either the host (which is GNU, but dynamically linked) nor anything assuming the real MUSL-LLVM?

I'm usually compiling for MUSL from a macOS host where it's more immediately apparent when builds try to naively use something from /usr or pkg-config, but even that is easier because I don't have to avoid LLVM's tooling.