[PATCH 2/4] terminal: don't assume stdin is /dev/tty
- From
- Phillip Wood <phillip.wood123@gmail.com>
- Date
- Mar 4, 2022, 13:11 UTC
- Message-ID
- <20220304131126.8293-3-phillip.wood123@gmail.com>
- In-Reply-To
- <20220304131126.8293-1-phillip.wood123@gmail.com>
From: Phillip Wood <phillip.wood@dunelm.org.uk>
read_key_without_echo() reads from stdin but uses /dev/tty when it disables echo. This is unfortunate as there no guarantee that stdin is the same device as /dev/tty. The perl version of "add -p" uses stdin when it sets the terminal mode, this commit does the same for the builtin version. There is still a difference between the perl and builtin versions though - the perl version will ignore any errors when setting the terminal mode[1] and will still read single bytes when stdin is not a terminal. The builtin version displays a warning if setting the terminal mode fails and switches to reading a line at a time.
[1] https://github.com/jonathanstowe/TermReadKey/blob/b061c913bbf7ff9bad9b4eea6caae189eacd6063/ReadKey.xs#L1090
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk> --- compat/terminal.c | 5 +++-- compat/terminal.h | 3 ++- 2 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/compat/terminal.c b/compat/terminal.c index bad8e04cd8..249836e78f 100644 --- a/compat/terminal.c +++ b/compat/terminal.c @@ -37,7 +37,8 @@ void restore_term(void) int save_term(unsigned flags) { if (term_fd < 0) - term_fd = open("/dev/tty", O_RDWR); + term_fd = (flags & SAVE_TERM_STDIN) ? 0 + : open("/dev/tty", O_RDWR); if (term_fd < 0) return -1; if (tcgetattr(term_fd, &old_term) < 0) @@ -362,7 +363,7 @@ int read_key_without_echo(struct strbuf *buf) static int warning_displayed; int ch; - if (warning_displayed || enable_non_canonical(0) < 0) { + if (warning_displayed || enable_non_canonical(SAVE_TERM_STDIN) < 0) { if (!warning_displayed) { warning("reading single keystrokes not supported on " "this platform; reading line instead"); diff --git a/compat/terminal.h b/compat/terminal.h index f24b91390d..f5655d0d0b 100644 --- a/compat/terminal.h +++ b/compat/terminal.h @@ -3,7 +3,8 @@ /* Save input and output settings */ #define SAVE_TERM_DUPLEX (1u << 0) - +/* Save stdin rather than /dev/tty (fails is stdin is not a terminal) */ +#define SAVE_TERM_STDIN (1u << 1) /* * Save the terminal attributes so they can be restored later by a * call to restore_term(). Note that every successful call to
-- 2.35.1