Description

Adds DOTNET_DbgCreateDumpToolPath environment variable to allow specifying a directory path where the createdump tool is located. In scenarios where createdump is not shipped with the NativeAOT runtime, users can now provide their own dump generation tool.

Note: This environment variable is only supported in NativeAOT applications and is ignored otherwise (not in other runtime configurations).

Implementation

• Modified PalCreateDumpInitialize() to check DOTNET_DbgCreateDumpToolPath for a directory path
• The runtime concatenates the directory path with "createdump" following the same pattern as the default behavior
• No file validation during initialization (aligned with commit c507305 which removed stat checks)
• Follows existing environment variable pattern using RhConfig::Environment::TryGetStringValue()
• Uses safe string handling with proper null-termination and buffer management
• Maintains backward compatibility: falls back to default behavior when not set

Usage

export DOTNET_DbgEnableMiniDump=1
export DOTNET_DbgCreateDumpToolPath=/path/to/directory
./myapp

The runtime will look for /path/to/directory/createdump

Customer Impact

Customers deploying NativeAOT in environments without createdump (custom distributions, minimal containers, embedded systems) currently cannot generate crash dumps. This prevents critical debugging in production scenarios.

Regression

No. This is a new opt-in feature with no impact on existing behavior. Only affects NativeAOT applications.

Testing

• NativeAOT runtime build verification (clr.nativeaotruntime)
• Code follows existing patterns for environment variable handling and memory management
• Documentation updated with usage examples and NativeAOT-only clarification using "ignored otherwise" wording to avoid ambiguity since NativeAOT uses a stripped-down version of CoreCLR
• Safe string handling verified

Risk

Low. New environment variable only used when explicitly set. Code path follows existing directory concatenation pattern used for default createdump lookup. No changes to existing dump generation logic. NativeAOT only, so no impact on other runtime configurations.

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