mbuffer Codebase Assistant

Provides expert guidance when working with the mbuffer measuring buffer tool codebase.

What This Skill Does

This skill gives you deep understanding of the mbuffer project architecture, build system, testing infrastructure, and threading model. Use it when modifying, debugging, or extending the mbuffer measuring buffer tool.

Project Context

mbuffer is a high-performance data buffering tool written in C with:

Build Instructions

Primary Build System (Autoconf/Make)

1. **Standard build:**

```bash

./configure

make

```

2. **Build with specific flags:**

```bash

env CFLAGS="-O -g -m64" ./configure

make

```

3. **Run test suite:**

```bash

make check

```

4. **Install:**

```bash

make install

```

5. **Clean build artifacts:**

```bash

make clean # Remove build artifacts

make distclean # Remove all generated files

```

Alternative Build System (CMake)

```bash

cmake .

cmake --build .

ctest # If ENABLE_TESTING is enabled

```

Code Architecture Guide

Core Files and Responsibilities

**Main Program:**

**I/O Components:**

**Supporting Infrastructure:**

Threading Architecture

**Producer-Consumer Pattern:**

**Synchronization Primitives:**

Buffer Management System

Testing Infrastructure

**Test Location:** `tests/` directory (test0.sh through test7.sh)

**Test Coverage:**

**Test Dependencies:**

Tests validate functionality using tar archives and MD5 checksums.

Configuration Management

**Config File Load Order:**

1. `/etc/mbuffer.rc`

2. `${SYSCONFDIR}/mbuffer.rc`

3. `~/.mbuffer.rc`

4. File in `$MBUFFERRC` environment variable

**Version Generation:**

Platform Support

| Platform | Status | Notes |

|----------|--------|-------|

| Linux | Fully supported | Primary development platform |

| Solaris | Fully supported | Full feature parity |

| FreeBSD | Supported | Some caveats apply |

| macOS | **Not supported** | Missing `sem_getvalue()` - see README |

**Requirements:**

Important Constraints

1. **macOS limitation:** The project explicitly does not support macOS due to missing POSIX semaphore functionality

2. **Thread safety:** All buffer access must respect semaphore/mutex protocol

3. **Multi-volume operations:** Require careful state management across volume boundaries

4. **Network mode:** IPv4/IPv6 support depends on system capabilities

When Modifying Code

1. **Threading changes:** Ensure proper synchronization with existing semaphores/mutexes

2. **Buffer operations:** Respect circular buffer boundaries and watermark thresholds

3. **I/O changes:** Test with both file and device backends

4. **Network code:** Verify both IPv4 and IPv6 paths

5. **Build changes:** Update both Autoconf and CMake files if modifying build logic

6. **Testing:** Add appropriate tests to `tests/` directory and update `make check` target