From 0038ff7254a27b55a9d42588719833d15d1cf0d2 Mon Sep 17 00:00:00 2001 From: Dominic Grimm Date: Tue, 11 Feb 2025 17:53:20 +0100 Subject: [PATCH] Add zig build system --- .gitignore | 22 +++++++++ build.zig | 98 ++++++++++++++++++++++++++++++++++++++++ build.zig.zon | 72 +++++++++++++++++++++++++++++ getauxval.c | 51 --------------------- src/getauxval_backport.c | 67 +++++++++++++++++++++++++++ 5 files changed, 259 insertions(+), 51 deletions(-) create mode 100644 .gitignore create mode 100644 build.zig create mode 100644 build.zig.zon delete mode 100644 getauxval.c create mode 100644 src/getauxval_backport.c diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..7e9e158 --- /dev/null +++ b/.gitignore @@ -0,0 +1,22 @@ +# This file is for zig-specific build artifacts. +# If you have OS-specific or editor-specific files to ignore, +# such as *.swp or .DS_Store, put those in your global +# ~/.gitignore and put this in your ~/.gitconfig: +# +# [core] +# excludesfile = ~/.gitignore +# +# Cheers! +# -andrewrk + +.zig-cache/ +zig-out/ +/release/ +/debug/ +/build/ +/build-*/ +/docgen_tmp/ + +# Although this was renamed to .zig-cache, let's leave it here for a few +# releases to make it less annoying to work with multiple branches. +zig-cache/ diff --git a/build.zig b/build.zig new file mode 100644 index 0000000..fe5780f --- /dev/null +++ b/build.zig @@ -0,0 +1,98 @@ +const std = @import("std"); + +// Although this function looks imperative, note that its job is to +// declaratively construct a build graph that will be executed by an external +// runner. +pub fn build(b: *std.Build) void { + // Standard target options allows the person running `zig build` to choose + // what target to build for. Here we do not override the defaults, which + // means any target is allowed, and the default is native. Other options + // for restricting supported target set are available. + const target = b.standardTargetOptions(.{}); + + // Standard optimization options allow the person running `zig build` to select + // between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall. Here we do not + // set a preferred release mode, allowing the user to decide how to optimize. + const optimize = b.standardOptimizeOption(.{}); + + const opt_elf64 = b.option(bool, "elf64", "ELF 64 bit").?; + const opt_file = b.option(bool, "file", "Get auxiliary vectors from /proc/self/auxv") orelse false; + + const lib = b.addStaticLibrary(.{ + .name = "getauxval-backport", + .target = target, + .optimize = optimize, + }); + + lib.linkLibC(); + + lib.addCSourceFile(.{ + .file = b.path("src/getauxval_backport.c"), + .flags = &.{ + if (!opt_elf64) "-DGETAUXVAL_BACKPORT_ELF32" else "", + if (opt_file) "-DGETAUXVAL_BACKPORT_FILE" else "", + }, + }); + + b.installArtifact(lib); + + // const exe = b.addExecutable(.{ + // .name = "getauxval-backport", + // .root_source_file = b.path("src/main.zig"), + // .target = target, + // .optimize = optimize, + // }); + + // // This declares intent for the executable to be installed into the + // // standard location when the user invokes the "install" step (the default + // // step when running `zig build`). + // b.installArtifact(exe); + + // // This *creates* a Run step in the build graph, to be executed when another + // // step is evaluated that depends on it. The next line below will establish + // // such a dependency. + // const run_cmd = b.addRunArtifact(exe); + + // // By making the run step depend on the install step, it will be run from the + // // installation directory rather than directly from within the cache directory. + // // This is not necessary, however, if the application depends on other installed + // // files, this ensures they will be present and in the expected location. + // run_cmd.step.dependOn(b.getInstallStep()); + + // // This allows the user to pass arguments to the application in the build + // // command itself, like this: `zig build run -- arg1 arg2 etc` + // if (b.args) |args| { + // run_cmd.addArgs(args); + // } + + // // This creates a build step. It will be visible in the `zig build --help` menu, + // // and can be selected like this: `zig build run` + // // This will evaluate the `run` step rather than the default, which is "install". + // const run_step = b.step("run", "Run the app"); + // run_step.dependOn(&run_cmd.step); + + // // Creates a step for unit testing. This only builds the test executable + // // but does not run it. + // const lib_unit_tests = b.addTest(.{ + // .root_source_file = b.path("src/root.zig"), + // .target = target, + // .optimize = optimize, + // }); + + // const run_lib_unit_tests = b.addRunArtifact(lib_unit_tests); + + // const exe_unit_tests = b.addTest(.{ + // .root_source_file = b.path("src/main.zig"), + // .target = target, + // .optimize = optimize, + // }); + + // const run_exe_unit_tests = b.addRunArtifact(exe_unit_tests); + + // // Similar to creating the run step earlier, this exposes a `test` step to + // // the `zig build --help` menu, providing a way for the user to request + // // running the unit tests. + // const test_step = b.step("test", "Run unit tests"); + // test_step.dependOn(&run_lib_unit_tests.step); + // test_step.dependOn(&run_exe_unit_tests.step); +} diff --git a/build.zig.zon b/build.zig.zon new file mode 100644 index 0000000..c3efca7 --- /dev/null +++ b/build.zig.zon @@ -0,0 +1,72 @@ +.{ + // This is the default name used by packages depending on this one. For + // example, when a user runs `zig fetch --save `, this field is used + // as the key in the `dependencies` table. Although the user can choose a + // different name, most users will stick with this provided value. + // + // It is redundant to include "zig" in this name because it is already + // within the Zig package namespace. + .name = "getauxval-backport", + + // This is a [Semantic Version](https://semver.org/). + // In a future version of Zig it will be used for package deduplication. + .version = "0.0.0", + + // This field is optional. + // This is currently advisory only; Zig does not yet do anything + // with this value. + //.minimum_zig_version = "0.11.0", + + // This field is optional. + // Each dependency must either provide a `url` and `hash`, or a `path`. + // `zig build --fetch` can be used to fetch all dependencies of a package, recursively. + // Once all dependencies are fetched, `zig build` no longer requires + // internet connectivity. + .dependencies = .{ + // See `zig fetch --save ` for a command-line interface for adding dependencies. + //.example = .{ + // // When updating this field to a new URL, be sure to delete the corresponding + // // `hash`, otherwise you are communicating that you expect to find the old hash at + // // the new URL. + // .url = "https://example.com/foo.tar.gz", + // + // // This is computed from the file contents of the directory of files that is + // // obtained after fetching `url` and applying the inclusion rules given by + // // `paths`. + // // + // // This field is the source of truth; packages do not come from a `url`; they + // // come from a `hash`. `url` is just one of many possible mirrors for how to + // // obtain a package matching this `hash`. + // // + // // Uses the [multihash](https://multiformats.io/multihash/) format. + // .hash = "...", + // + // // When this is provided, the package is found in a directory relative to the + // // build root. In this case the package's hash is irrelevant and therefore not + // // computed. This field and `url` are mutually exclusive. + // .path = "foo", + + // // When this is set to `true`, a package is declared to be lazily + // // fetched. This makes the dependency only get fetched if it is + // // actually used. + // .lazy = false, + //}, + }, + + // Specifies the set of files and directories that are included in this package. + // Only files and directories listed here are included in the `hash` that + // is computed for this package. Only files listed here will remain on disk + // when using the zig package manager. As a rule of thumb, one should list + // files required for compilation plus any license(s). + // Paths are relative to the build root. Use the empty string (`""`) to refer to + // the build root itself. + // A directory listed here means that all files within, recursively, are included. + .paths = .{ + "build.zig", + "build.zig.zon", + "src", + // For example... + //"LICENSE", + //"README.md", + }, +} diff --git a/getauxval.c b/getauxval.c deleted file mode 100644 index 28acb0f..0000000 --- a/getauxval.c +++ /dev/null @@ -1,51 +0,0 @@ -#include -#include - -#ifdef GETAUXVAL_BACKPORT_ELF64 -typedef Elf64_auxv_t __auxv_t; -#else -typedef Elf32_auxv_t __auxv_t; -#endif - -#define AUXV_FILE "/proc/self/auxv" - -unsigned long getauxval(unsigned long type) { -#ifdef GETAUXVAL_BACKPORT_DEBUG - printf("getauxval: search started for type: %lu\n", type); -#endif - - FILE *f = fopen(AUXV_FILE, "rb"); - if (f == NULL) - return 1; - - unsigned long val = AT_NULL; - __auxv_t aux; - -#ifdef GETAUXVAL_BACKPORT_DEBUG - unsigned int i = 0; -#endif - - while (fread(&aux, sizeof(aux), 1, f) == 1 && aux.a_type != AT_NULL) { -#ifdef GETAUXVAL_BACKPORT_DEBUG - printf("getauxval: current type: %u [%u]\n", aux.a_type, i); -#endif - - if (aux.a_type == type) { -#ifdef GETAUXVAL_BACKPORT_DEBUG - printf("getauxval: found %u with value: 0x%x\n", aux.a_type, - aux.a_un.a_val); -#endif - - val = aux.a_un.a_val; - break; - } - -#ifdef GETAUXVAL_BACKPORT_DEBUG - i++; -#endif - } - - fclose(f); - - return val; -} diff --git a/src/getauxval_backport.c b/src/getauxval_backport.c new file mode 100644 index 0000000..85c49fd --- /dev/null +++ b/src/getauxval_backport.c @@ -0,0 +1,67 @@ +#include +#include +#include + +#ifdef GETAUXVAL_BACKPORT_ELF64 +typedef Elf64_auxv_t __auxv_t; +#else +typedef Elf32_auxv_t __auxv_t; +#endif + +#define AUXV_FILE "/proc/self/auxv" + +#ifdef GETAUXVAL_BACKPORT_FILE + +unsigned long __getauxval_file(unsigned long type) { + FILE *f = fopen(AUXV_FILE, "rb"); + if (f == NULL) + return 1; + + unsigned long val = 0; + __auxv_t aux; + + while (fread(&aux, sizeof(aux), 1, f) == 1 && aux.a_type != AT_NULL) { + if (aux.a_type == type) { + val = aux.a_un.a_val; + break; + } + } + + fclose(f); + + return val; +} + +#else + +extern char **environ; + +char **envp_auxv = NULL; + +unsigned long __getauxval_envp(unsigned long type) { + if (envp_auxv == NULL) { + envp_auxv = environ; + while (*envp_auxv++ != NULL) + ; + } + + __auxv_t *auxv; + + for (auxv = (__auxv_t *)envp_auxv; auxv->a_type != AT_NULL; auxv++) { + if (auxv->a_type == type) { + return auxv->a_un.a_val; + } + } + + return 0; +} + +#endif + +unsigned long getauxval(unsigned long type) { +#ifdef GETAUXVAL_BACKPORT_FILE + return __getauxval_file(type); +#else + return __getauxval_envp(type); +#endif +}