From d1d6efba6a3906dfd1d871f0eb57716aa58beff5 Mon Sep 17 00:00:00 2001
From: Aleksa Sarai <cyphar@cyphar.com>
Date: Sat, 7 Sep 2024 03:10:54 +1000
Subject: [PATCH] capi: switch to cargo-c

It seems cargo-c is the "recommended" way of building distro-friendly
.so's for Rust crates and so switch to that.

The lack of fine-grained SONAME control might be an issue in the future
(when we do a 1.0 release, we probably don't want to do a full SONAME
API breakage -- but maybe we can do a 1.0 release when pathrs is ready
for packaging anyway). It also seems that the ability to do Version.map
stuff is limited with cargo-c, but we can cross that bridge when we get
to it (for the most part there aren't many cargo-c-specific changes).

Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
---
 .github/workflows/bindings.yml |  9 +++++++++
 Cargo.toml                     | 18 ++++++++++++++----
 Makefile                       | 10 +++++-----
 build.rs                       | 30 ------------------------------
 4 files changed, 28 insertions(+), 39 deletions(-)
 delete mode 100644 build.rs

diff --git a/.github/workflows/bindings.yml b/.github/workflows/bindings.yml
index 7210f471..5e0fd8ef 100644
--- a/.github/workflows/bindings.yml
+++ b/.github/workflows/bindings.yml
@@ -33,6 +33,9 @@ jobs:
       - uses: actions/checkout@v4
       # Build and install libpathrs.so.
       - uses: dtolnay/rust-toolchain@stable
+      - uses: taiki-e/install-action@v2
+        with:
+          tool: cargo-c
       - name: build libpathrs
         run: make release
       - name: install libpathrs
@@ -50,6 +53,9 @@ jobs:
       - uses: actions/checkout@v4
       # Build and install libpathrs.so.
       - uses: dtolnay/rust-toolchain@stable
+      - uses: taiki-e/install-action@v2
+        with:
+          tool: cargo-c
       - name: build libpathrs
         run: make release
       - name: install libpathrs
@@ -73,6 +79,9 @@ jobs:
       - uses: actions/checkout@v4
       # Build and install libpathrs.so.
       - uses: dtolnay/rust-toolchain@stable
+      - uses: taiki-e/install-action@v2
+        with:
+          tool: cargo-c
       - name: build libpathrs
         run: make release
       - name: install libpathrs
diff --git a/Cargo.toml b/Cargo.toml
index 520935f9..cc94de56 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -33,7 +33,20 @@ rust-version = "1.63"
 maintenance = { status = "experimental" }
 
 [lib]
-crate-type = ["rlib", "cdylib", "staticlib"]
+crate-type = ["rlib"]
+
+[package.metadata.capi.header]
+subdirectory = false
+
+[package.metadata.capi.library]
+name = "pathrs"
+# TODO: In order to avoid breaking dependencies when we do our 1.0 release, we
+#       might need to fake the so version...
+#version = "1.0.0"
+#version_suffix_components = 1
+# Since we are cdylib, panic!s will cause aborts once they hit the FFI barrier
+# anyway. We might as well reduce our code size if we're doing it.
+rustflags = "-Cpanic=abort"
 
 [features]
 capi = ["dep:rand"]
@@ -43,9 +56,6 @@ _test_as_root = []
 [profile.release]
 # Enable link-time optimisations.
 lto = true
-# Since we are cdylib, panic!s will cause aborts once they hit the FFI barrier
-# anyway. We might as well reduce our code size if we're doing it.
-panic = "abort"
 
 [dependencies]
 bitflags = "^2"
diff --git a/Makefile b/Makefile
index 773497c4..e821972b 100644
--- a/Makefile
+++ b/Makefile
@@ -18,19 +18,19 @@ CARGO ?= cargo
 CARGO_NIGHTLY ?= cargo +nightly
 
 SRC_FILES = $(shell find . -name '*.rs')
-CAPI_FEATURES = --features=capi
+DESTDIR ?= /
 
 .PHONY: debug
 debug: target/debug
 
 target/debug: $(SRC_FILES)
-	$(CARGO) build $(CAPI_FEATURES)
+	$(CARGO) cbuild
 
 .PHONY: release
 release: target/release
 
 target/release: $(SRC_FILES)
-	$(CARGO) build $(CAPI_FEATURES) --release
+	$(CARGO) cbuild --release
 
 .PHONY: smoke-test
 smoke-test:
@@ -83,7 +83,7 @@ docs:
 
 .PHONY: install
 install: release
-	@echo "If you want to configure the install paths, use ./install.sh directly."
+	@echo "If you want to configure the install paths, use 'cargo cinstall' directly."
 	@echo "[Sleeping for 3 seconds.]"
 	@sleep 3s
-	./install.sh
+	cargo cinstall --release --destdir=$(DESTDIR) --prefix=/usr
diff --git a/build.rs b/build.rs
deleted file mode 100644
index e3f0fe94..00000000
--- a/build.rs
+++ /dev/null
@@ -1,30 +0,0 @@
-/*
- * libpathrs: safe path resolution on Linux
- * Copyright (C) 2019-2021 Aleksa Sarai <cyphar@cyphar.com>
- * Copyright (C) 2019-2021 SUSE LLC
- *
- * This program is free software: you can redistribute it and/or modify it
- * under the terms of the GNU Lesser General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or (at your
- * option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
- * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
- * for more details.
- *
- * You should have received a copy of the GNU Lesser General Public License
- * along with this program. If not, see <https://www.gnu.org/licenses/>.
- */
-
-use std::env;
-
-fn main() {
-    // Add DT_SONAME to our cdylibs.
-    let name = "pathrs";
-    let major = env::var("CARGO_PKG_VERSION_MAJOR").unwrap();
-    println!(
-        "cargo:rustc-cdylib-link-arg=-Wl,-soname,lib{}.so.{}",
-        name, major
-    );
-}