Reset the child signal mask before exec - #50
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When spawning a process via Runtime.exec() or ProcessBuilder, the executed process inherits the signal mask of the JVM thread that spawned it. The JVM's signal mask is an implementation detail of the runtime, and not part of the execution environment a child program expects. The mask must therefore be cleared when spawning child processes: otherwise, they may exhibit unexpected behaviour depending on which signals are blocked (e.g. cannot be interrupted with SIGINT, will not receive SIGPIPE when writing to a closed pipe, etc.). Fix by installing an empty signal mask in the child immediately before executing the target program. Fixes #49 (BZ#126539) Signed-off-by: Guillermo Rodríguez <grodriguez@ingelabs.com>
phvega
approved these changes
Jul 31, 2026
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CI is failing on macOS. It seems to be the "exec should not leak fds" Malva test, so unrelated to this PR. But we should fix that first. Will have a look. |
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Fixed Malva test, CI is green now. |
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When spawning a process via Runtime.exec() or ProcessBuilder, the executed process inherits the signal mask of the JVM thread that spawned it.
The JVM's signal mask is an implementation detail of the runtime, and not part of the execution environment a child program expects. The mask must therefore be cleared when spawning child processes: otherwise, they may exhibit unexpected behaviour depending on which signals are blocked (e.g. cannot be interrupted with SIGINT, will not receive SIGPIPE when writing to a closed pipe, etc.).
Fix by installing an empty signal mask in the child immediately before executing the target program.
Fixes #49 (BZ#126539)