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libdwarfs wrapper

This is libdwarfs-wr - a wrapper for https://github.com/mhx/dwarfs core library that provides the following features:

• C interface (as opposed to dwarfs C++ API)
• fd (file descriptor) addressing above dwarfs inode implementation

CMake Project Options

• WITH_TESTS, default: ON -- If this option is ON, the build script looks for Google Test, installs INCBIN, and builds Google tests and a static test application.
• WITH_ASAN, default: ON -- If this option is ON, address and memory sanitizer tests are performed.
• WITH_COVERAGE, default: ON -- If this option is ON, test coverage analysis is performed using Codecov.
• RB_W32, default: OFF -- If this option is ON, the version integrated with the Ruby library is built.
• WITH_LINK_TEST, default: ON -- If this option is ON, symbolic/hard link tests are enabled.

jemalloc Library Build on macOS

The libdwarfs build script creates an additional jemalloc installation on macOS. This is done to satisfy the magic applied by folly during linking but uses a static library. If the library is created in an emulated environment (QEMU, Rosetta, etc.), there are known issues (jemalloc issue #1997) where jemalloc incorrectly defines the number of significant virtual address bits (lg-vaddr parameter).

These issues can be fixed by explicitly setting the --with-lg-vaddr parameter for the jemalloc build. We decided not to automate this since we do not feel that we can provide reasonable test coverage. Instead, our build script accepts the LG_VADDR environment variable and passes it to the jemalloc build as --with-lg-vaddr=${LG_VADDR}.

Simple script to set LG_VADDR. Please note that it is provided for illustration only.

#!/bin/bash

# Check the CPU architecture
ARCH=$(uname -m)

# Check if running under Rosetta 2 emulation
if [[ "$ARCH" == "x86_64" && $(sysctl -n sysctl.proc_translated) == "1" ]]; then
  echo "Running on Apple Silicon under Rosetta 2 emulation"
  export LG_VADDR=39
elif [[ "$ARCH" == "arm64" ]]; then
  echo "Running on Apple Silicon"
  export LG_VADDR=39
else
  echo "Running on Intel Silicon"
  export LG_VADDR=48
fi

echo "Setting lg-vaddr to $LG_VADDR"