ksh crashed if you pressed Ctrl+C or Ctrl+D on a PS2 prompt while
you haven't finished entering a $(command substitution). It
corrupts subsequent command substitutions. Sometimes the situation
recovers, sometimes the shell crashes.
Simple crash reproducer:
$ PS1="\$(echo foo) \$(echo bar) \$(echo baz) > "
foo bar baz > echo $( <-- now press Ctrl+D
> ksh: syntax error: `(' unmatched
Memory fault
The same happens with Ctrl+C, minus the syntax error message.
The problem is that the lexer state becomes inconsistent when the
lexer is interrupted in the middle of reading a command
substitution of the form $( ... ). This is tracked in the
'lexd.dolparen' variable in the lexer state struct.
Resetting that variable is sufficient to fix this issue. However,
in this commit I prefer to just reinitialise the lexer state
completely to pre-empt any other possible issues. Whether there was
a syntax error or the user pressed Ctrl+C, we just interrupted all
lexing and parsing, so the lexer *should* restart from scratch.
src/cmd/ksh93/sh/fault.c: sh_fault():
- If the shell is in an interactive state (e.g. not a subshell) and
SIGINT was received, reinitialise the lexer state. This fixes the
crash with Ctrl+C.
src/cmd/ksh93/sh/lex.c: sh_syntax():
- When handling a syntax error, reset the lexer state. This fixes
the crash with Ctrl+D.
NEWS:
- Also add the forgotten item for the previous fix (re: 2322f939).
feedc05037