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Jon Ross-Perkins
3070e5cfc6
When finding an executable, this validates that the returned binary is a symlink back to the same thing as /proc/self/exe, also using that as a fallback for different things. Looking back at #3912, we started using `findProgramByName` in order to avoid path canonicalization done by `GetMainExecutable`. That created issues as in #5096, wherein an `argv[0]` that's not explicit enough (`llvm-symbolizer` instead of the full path, done in [LLVM's Signals.cpp](https://github.com/llvm/llvm-project/blob/4f60f45130c6bd96c79e468fe9927a29af760f56/llvm/lib/Support/Signals.cpp#L198)) leads to incorrect results (finding an `llvm-symbolizer` in `$PATH`). One option to fix this would be to patch LLVM to provide an absolute path for `llvm-symbolizer`. However, I'll suggest that passing a filename in `argv[0]` is not terribly uncommon, and could be a migration limitation if we force it. The failure mode is also opaque; for example: ``` $ /bin/sh -c "exec -a llvm-symbolizer ./bazel-bin/toolchain/carbon" error: expected carbon-busybox symlink at `/usr/lib/llvm-19/bin/llvm-symbolizer` ``` Combined with the `setenv` of `LLVM_SYMBOLIZER_PATH` in `busybox_main.cpp`, this is intended to fix #5096.
41 lines
1.3 KiB
C++
41 lines
1.3 KiB
C++
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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#ifndef CARBON_TOOLCHAIN_INSTALL_BUSYBOX_INFO_H_
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#define CARBON_TOOLCHAIN_INSTALL_BUSYBOX_INFO_H_
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#include <filesystem>
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#include <optional>
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#include <string>
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#include "common/error.h"
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namespace Carbon {
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// An optional override of argv0, particularly used by `//toolchain/carbon` to
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// get desired behavior without further special-casing.
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inline constexpr const char* Argv0OverrideEnv = "CARBON_ARGV0_OVERRIDE";
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struct BusyboxInfo {
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// The path to `carbon-busybox`.
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std::filesystem::path bin_path;
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// The mode, such as `carbon` or `clang`.
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std::optional<std::string> mode;
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};
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// Returns the busybox information, given argv[0].
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//
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// Extracts the desired mode for the busybox from the initial command name.
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//
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// Checks if the path in argv0 is an executable in a valid Carbon install, or a
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// symlink to such an executable, and sets `bin_path` to the path of
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// `lib/carbon/carbon-busybox` within that install.
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//
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// If unable to locate a plausible busybox binary, returns an error instead.
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auto GetBusyboxInfo(const char* argv0) -> ErrorOr<BusyboxInfo>;
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} // namespace Carbon
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#endif // CARBON_TOOLCHAIN_INSTALL_BUSYBOX_INFO_H_
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