ghostscope-runtime-analysis

name

ghostscope-runtime-analysis

description

Explain GhostScope and turn the project docs into concrete tracing commands, trace scripts, privilege setup, and issue-report workflows for source-aware runtime analysis. Use when the user asks how to install GhostScope, provide source tree and DWARF inputs, handle eBPF privileges, attach to a PID or binary, choose between `-p` and `-t`, inspect variables or source-aware call stacks, write GhostScope trace scripts, use Input Mode commands, work through container or PID-namespace CLI scenarios, or triage GhostScope failures, crashes, and GitHub issue reports.

GhostScope Runtime Analysis

Overview

Translate GhostScope documentation into runnable commands and minimal trace scripts. Prefer live GhostScope output and repository docs as the source of truth. Treat this skill and its references as routing and workflow guidance, not as a frozen copy of GhostScope behavior. When the user is writing in Chinese, prefer the docs/zh/ counterparts first.

Workflow

1. Classify the request before answering.

• For any answer involving CLI flags, debug-info loading, logging behavior, startup reports, or script syntax, derive the current behavior dynamically: run ghostscope --help or the relevant subcommand help for flags, run ghostscope --script-help for DSL syntax, and read the current docs under docs/ or docs/zh/ for configuration semantics. Use references/cli-cookbook.md only as a command-template fallback.
• If live CLI output, docs, and source comments disagree, do not silently choose one. Say what disagrees, inspect the implementation when available, and base the answer on the implementation plus current docs.
• Capabilities, positioning, tool comparisons, or "should I use GhostScope here?": read references/doc-map.md, then use README.md, docs/comparison.md, and docs/faq.md or README-zh.md, docs/zh/comparison.md, and docs/zh/faq.md.
• Installation, permissions, or debug symbols: read references/cli-cookbook.md, then docs/install.md or docs/zh/install.md.
• Exact CLI flags or launch syntax: run ghostscope --help first, and use subcommand help such as ghostscope bpffs prune --help when relevant. If ghostscope is unavailable but the shared workspace is the GhostScope repo, fall back to references/cli-cookbook.md, then docs/configuration.md or docs/zh/configuration.md.
• TUI commands such as trace, info, source, save traces, or srcpath: read references/cli-cookbook.md, then docs/input-commands.md or docs/zh/input-commands.md.
• Trace script authoring: run ghostscope --script-help first and treat its output as the source of truth for the current installed DSL. If ghostscope is unavailable but the shared workspace is the GhostScope repo, fall back to docs/scripting.md or docs/zh/scripting.md.
• Container or PID confusion: read docs/container.md or docs/zh/container.md.
• Limits or caveats: read docs/limitations.md or docs/zh/limitations.md.
• Crash, cannot-capture, or bug-report preparation: read references/issue-reporting.md, then docs/install.md, docs/container.md, and docs/limitations.md or their docs/zh/ counterparts.

2. Check prerequisites before giving commands.

• If ghostscope is not installed or not found, recommend installing it first with curl -fsSL https://raw.githubusercontent.com/swananan/ghostscope/main/scripts/install.sh | bash.
• GhostScope currently targets Linux on x86_64.
• eBPF tracing usually needs sudo or equivalent capabilities.
• If the current privilege model is unclear, tell the user explicitly. Recommend either granting GhostScope eBPF-related capabilities with setcap or running a prepared wrapper script with sudo.
• If the source tree location is not already known, first try to discover it from the shared workspace, local filesystem, build paths, or command context before asking the user. GhostScope is most effective when it can be used together with the relevant source tree.
• DWARF debug information is required in the target binary or a separate debug file.
• When separate debug information is involved, check the current install and configuration docs before naming supported sources, validation rules, or search paths.
• If the relevant module's DWARF debug info or debug-file status is unknown, first inspect the target locally when possible. If it is still missing or unclear, tell the user and ask them to provide it. At minimum, the modules they care about must have debug info.
• For ghostscope -p <PID>, use the PID visible in the same environment where GhostScope runs.
• Do not suggest running GhostScope and GDB against the same target at the same time.

3. Choose the operating mode that matches the task.

• Use -p <PID> for one already-running process.
• Use -t <PATH> when the user wants startup coverage, wants to trace all processes using a binary or library, or is targeting a shared library explicitly.
• Use --script-file for repeatable command-line workflows.
• Use TUI trace and info commands for interactive exploration.

4. Answer with executable guidance.

• Start with a short capability or constraint summary only when it affects the recommendation.
• If prerequisites are missing, say exactly what is missing first: installation, source path, debug info, or privileges.
• Then give exact shell commands.
• If the user needs TUI interaction, include the minimum command-panel sequence.
• If the user needs a reusable trace file, emit a valid trace <pattern> { ... } block.
• If the user needs an inline script body after trace <target>, emit only the statements inside the block, not another top-level trace.
• When the user asks how execution reached a point, or asks for call context, include bt full; in the trace block. Pair it with a print line when a request, ID, argument, or state value helps identify the event. Add --backtrace-depth <N> only when the user asks to bound stack depth or a compact demo output is explicitly needed.
• When generating a GhostScope trace script and the relevant source path is known, also include the source-backed rationale:
  • quote or summarize the specific function signature, source lines, struct fields, branches, or variables the script depends on
  • explain why each probe target, printed variable, condition, or field access matches that source context
  • make it easy for the user to verify the script against their code instead of only pasting DSL
• If the source path is unknown or the relevant source cannot be inspected after local discovery attempts, say that explicitly before giving the script and ask the user for the checkout path.
• If DWARF or debug info is missing, say that source-backed variable tracing and explanation will be partial or unreliable.
• If the command needs privileges and the user is likely to rerun it, prefer offering either a setcap command or a ready-to-run sudo wrapper script.
• When asking the user for logs, check the current logging docs/help first and include the flags or config required to actually enable log output.

5. Avoid common mistakes.

• Do not invent GhostScope DSL syntax. Validate it against ghostscope --script-help, or fall back to docs/scripting.md or docs/zh/scripting.md only when GhostScope is unavailable.
• Do not guess PID conversions across containers. Follow the current-namespace PID rule from docs/container.md.
• Do not overpromise unsupported behavior. Check docs/limitations.md for caveats first.
• Do not pretend source-line workflows are fully ready when the source tree path cannot be discovered. Ask the user for the source checkout path instead.
• Do not pretend DWARF-backed variable tracing is ready when the relevant module lacks debug info. Ask the user for the debug-enabled binary or debug file instead.
• Do not suggest --debug-file, debug search paths, debuginfod, or logging flags from memory. Re-check current CLI help and docs, then explain the target binding and enabled output path in the command you provide.
• For -t shared-library targets where new processes must expose globals, mention --enable-sysmon-shared-lib.
• When source paths do not resolve, prefer srcpath map over telling the user to move files manually.
• When docs and generated examples seem inconsistent, prefer the installed CLI help output from ghostscope --help and relevant subcommand help.

6. Prepare issue reports when the problem still looks like a GhostScope bug.

• First rule out missing privileges, missing debug symbols, wrong -p PID semantics, and known -t shared-library caveats.
• If the user still has an unexplained failure, crash, or incorrect capture result, gather the exact command, trace script, config, source-tree path, debug-file path or debug-symbol status, logs, expected behavior, actual behavior, and environment notes.
• Write the issue draft to /tmp/ghostscope-issue-*.md with scripts/prepare_issue_report.py.
• Recommend filing it at https://github.com/swananan/ghostscope/issues.
• Prefer preparing as much of the issue as possible for the user instead of only telling them to "open an issue".

References

• Use doc-map.md to choose the right docs quickly.
• Use cli-cookbook.md for concrete command patterns and common workflows.
• Use issue-reporting.md for escalation and GitHub issue preparation.