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sgrif / pq-sys

Auto-generated rust bindings for libpq
Apache License 2.0
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Static linking needs to include `openssl` somehow. #25

Closed emk closed 4 years ago

emk commented 5 years ago

Hello! Thank you for maintaining pq-sys. I've used it in a lot of projects, and it works very nicely.

I'm the maintainer of rust-musl-builder, which makes it possible to statically link Rust applications using the postgres, diesel and openssl crates. (It's apparently pretty popular, with over 450 thousand downloads on Docker Hub.)

Recently, some users of rust-musl-builder have been encountering a linking problem with pq-sys. This also seems to affect users of muslrust, the other cross-building library:

  = note: "cc" "-Wl,--as-needed" "-Wl,-z,noexecstack" "-Wl,--eh-frame-hdr" "-m64" "-nostdlib" "/home/rust/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-musl/lib/crt1.o" "/home/rust/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-musl/lib/crti.o" "-L" "/home/rust/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-musl/lib" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/using_diesel-94aa5cadffcea30e.using_diesel.dqcexic7-cgu.0.rcgu.o" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/using_diesel-94aa5cadffcea30e.using_diesel.dqcexic7-cgu.1.rcgu.o" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/using_diesel-94aa5cadffcea30e.using_diesel.dqcexic7-cgu.10.rcgu.o" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/using_diesel-94aa5cadffcea30e.using_diesel.dqcexic7-cgu.11.rcgu.o" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/using_diesel-94aa5cadffcea30e.using_diesel.dqcexic7-cgu.12.rcgu.o" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/using_diesel-94aa5cadffcea30e.using_diesel.dqcexic7-cgu.13.rcgu.o" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/using_diesel-94aa5cadffcea30e.using_diesel.dqcexic7-cgu.14.rcgu.o" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/using_diesel-94aa5cadffcea30e.using_diesel.dqcexic7-cgu.15.rcgu.o" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/using_diesel-94aa5cadffcea30e.using_diesel.dqcexic7-cgu.2.rcgu.o" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/using_diesel-94aa5cadffcea30e.using_diesel.dqcexic7-cgu.3.rcgu.o" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/using_diesel-94aa5cadffcea30e.using_diesel.dqcexic7-cgu.4.rcgu.o" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/using_diesel-94aa5cadffcea30e.using_diesel.dqcexic7-cgu.5.rcgu.o" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/using_diesel-94aa5cadffcea30e.using_diesel.dqcexic7-cgu.6.rcgu.o" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/using_diesel-94aa5cadffcea30e.using_diesel.dqcexic7-cgu.7.rcgu.o" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/using_diesel-94aa5cadffcea30e.using_diesel.dqcexic7-cgu.8.rcgu.o" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/using_diesel-94aa5cadffcea30e.using_diesel.dqcexic7-cgu.9.rcgu.o" "-o" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/using_diesel-94aa5cadffcea30e" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/using_diesel-94aa5cadffcea30e.3n7t9phqceru8m8i.rcgu.o" "-Wl,--gc-sections" "-no-pie" "-Wl,-zrelro" "-Wl,-znow" "-Wl,-O1" "-nodefaultlibs" "-L" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps" "-L" "/home/rust/src/target/release/deps" "-L" "/home/rust/src/target/x86_64-unknown-linux-musl/release/build/libsqlite3-sys-ac3cf7454f406832/out" "-L" "/usr/local/musl/lib" "-L" "/usr/local/musl/lib/" "-L" "/home/rust/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-musl/lib" "-Wl,-Bstatic" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/libopenssl-0de50740ee181784.rlib" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/libopenssl_sys-89c6410693b927d6.rlib" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/liblibc-6265db6daf6f0d94.rlib" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/liblazy_static-5cac84b776fcd98b.rlib" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/libforeign_types-23f459ebafab2c61.rlib" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/libforeign_types_shared-1eba4aeaa81c6d19.rlib" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/libdiesel-c89a5a6bebad19a9.rlib" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/liblibsqlite3_sys-818909750b3afa36.rlib" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/libpq_sys-dc85b10baeb00fc3.rlib" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/libbyteorder-9272cb6794a9382c.rlib" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/libbitflags-b8224b03590c6c21.rlib" "/home/rust/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-musl/lib/libstd-af9362ed5d81a840.rlib" "/home/rust/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-musl/lib/libpanic_unwind-4d55a38564aae54a.rlib" "/home/rust/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-musl/lib/libbacktrace_sys-f8521075e248b627.rlib" "/home/rust/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-musl/lib/libunwind-7c91ffdc8da860d3.rlib" "/home/rust/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-musl/lib/librustc_demangle-0ad27b9879d551d3.rlib" "/home/rust/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-musl/lib/liblibc-588f18eae3ea58be.rlib" "/home/rust/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-musl/lib/liballoc-4ebf5caee903d98f.rlib" "/home/rust/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-musl/lib/librustc_std_workspace_core-8895b32baedb08c6.rlib" "/home/rust/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-musl/lib/libcore-6a9d233d01acc350.rlib" "/home/rust/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-musl/lib/libcompiler_builtins-851bb3b5f6c4db49.rlib" "-Wl,-Bdynamic" "-lpq" "-static" "/home/rust/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-musl/lib/crtn.o"
  = note: /usr/local/musl/lib/libpq.a(fe-connect.o): In function `connectFailureMessage':
          fe-connect.c:(.text+0xa12): undefined reference to `strlcpy'
...

Investigation suggests that the problem is that these libraries:

"/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/libopenssl-0de50740ee181784.rlib" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/libopenssl_sys-89c6410693b927d6.rlib" "/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/liblibc-6265db6daf6f0d94.rlib"

...appear before:

"/home/rust/src/target/x86_64-unknown-linux-musl/release/deps/libpq_sys-dc85b10baeb00fc3.rlib"

Manually reordering these will cause the linker to succeed.

The underlying problem sees to be that a statically-linked libpq doesn't actually pull in a statically linked libopenssl or the relevant portions of musl-libc's libc.

The easiest fix seems to be including the following in main.rs:

// The order of these two matters!
//
// If you reverse them, the build will fail.
extern crate openssl;
#[macro_use]
extern crate diesel;

But this is fragile, and the exact details seem to change from one release of rustc to the next. You can find a working example here, and it should break if you reorder the extern crate declarations.

Probably the easiest fix (kludge?) for this would be to include extern crate openssl_sys; somewhere in pq-sys, at least when PQ_LIB_STATIC_X86_64_UNKNOWN_LINUX_MUSL=1 is set. That feels slightly hackish, but it would delegate responsibility for correctly finding and linking libopenssl to the openssl_sys crate, which has a fairly fancy cross-platform build system.

Once again, thank you so much for your crate, and for maintaining it over all these years! If there's anything I can do to help sort this out, please let me know! I'd be happy to prepare a PR for you to review, or whatever else is needed.

sgrif commented 5 years ago

PR sounds great

golddranks commented 4 years ago

Hi, I'm the maintainer of https://gitlab.com/rust_musl_docker/image and I recently ran into this problem also. Is there any movement fixing this?

golddranks commented 4 years ago

@emk Apparently there hasn't been a PR fixing this. Could you elaborate why the order of the linker flags matter? Is the problem that libpq pulls in a dependency to OpenSSL? ( https://github.com/postgres/postgres/blame/master/src/interfaces/libpq/fe-secure-openssl.c#L702-L715 )

golddranks commented 4 years ago

From https://github.com/clux/muslrust/issues/49 , I got the impression libpq can be built with support for SSL or not, and depending on that the linking might fail, if it doesn't find the object. I wonder what's the correct way for this crate to detect that – is there a way to detect that and insert a dependence, or should the build just be configurable via an env var (hoping that the users will find out about that and set it if they need to.)

emk commented 4 years ago

I'm still getting reports of similar errors occasionally, and we have several long bug reports over at https://github.com/emk/rust-musl-builder/issues/69 and https://github.com/emk/rust-musl-builder/issues/64. Unfortunately, I've been busy lately, and I've forgotten the details. But if anybody wants to take a look, please feel welcome.

golddranks commented 4 years ago

I managed to consistently reproduce this. Here's a Dockerized repro: https://github.com/golddranks/pq_link_test