Send EOF to debugged inferior when its input stream is closed

[anydoby]

Problem

When debugging a C/C++ program with GDB on Linux, the program can never receive EOF on stdin:

• With standard input redirected from a file (Common tab → Input File), a program that reads until EOF (e.g. while (scanf("%d %d %d", &a, &b, &c) == 3)) hangs on the last read.
• The console's manual EOF action (Ctrl+D) has no effect either.

The same launch works in run mode, and the program works in a terminal with ./prog < file.

Cause

For debug sessions, StartOrRestartProcessSequence_7_0 attaches the inferior to a PersistentPTY. Its output stream deliberately ignores close() so the PTY can be reused when the inferior is restarted from the GDB console. As a result, MIInferiorProcess.getOutputStream().close(), which is what the platform calls for the console EOF action and, with eclipse-platform/eclipse.platform#2969, at the end of a stdin input file, never writes the EOT that a regular PTYOutputStream (used in run mode) sends on close.

Fix

MIInferiorProcess.getOutputStream() now returns, for a PersistentPTY on non-Windows platforms, a thin wrapper whose close() writes EOT to the PTY while the inferior is running and keeps the PTY open.

closeIO(), which CDT calls itself on termination and dispose, still closes the underlying PTY stream directly. That's a no-op for a PersistentPTY, as before, so no stray EOT is left in the PTY for a restarted inferior. Windows and the no-PTY (GDB MI stream) mode are unchanged.

Testing

Verified manually on Linux (GDB 15.1) against CDT 12.6 with a C program reading stdin until EOF:

• Debug with Input File set: the program reads the file, gets EOF and exits normally (previously hung).
• Debug without an input file, typing into the console, then Ctrl+D: the program gets EOF (previously nothing happened).
• Restarting the debug session afterwards: the restarted program reads input normally.

I didn't add an automated test, because reproducing this needs a real GDB and PTY. Happy to add one to dsf.gdb.tests if there's a preferred pattern, and to bump the bundle version if the API baseline check requires it.

Related platform fix: eclipse-platform/eclipse.platform#2969 (Bug 513713).

🤖 Generated with Claude Code