From a277506a64404e6c4472ff89c944c4f353db1c33 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Sun, 16 Jan 2022 23:54:46 +0100 Subject: shell: add comments about SIGINT-related problems Signed-off-by: Denys Vlasenko --- shell/ash.c | 13 ++++++++----- shell/shell_common.c | 1 + 2 files changed, 9 insertions(+), 5 deletions(-) (limited to 'shell') diff --git a/shell/ash.c b/shell/ash.c index ca5c755b6..086773dd7 100644 --- a/shell/ash.c +++ b/shell/ash.c @@ -664,7 +664,7 @@ raise_exception(int e) /* * Called when a SIGINT is received. (If the user specifies * that SIGINT is to be trapped or ignored using the trap builtin, then - * this routine is not called.) Suppressint is nonzero when interrupts + * this routine is not called.) suppress_int is nonzero when interrupts * are held using the INT_OFF macro. (The test for iflag is just * defensive programming.) */ @@ -695,13 +695,12 @@ raise_interrupt(void) } while (0) #endif -static IF_ASH_OPTIMIZE_FOR_SIZE(inline) void +static IF_NOT_ASH_OPTIMIZE_FOR_SIZE(inline) void int_on(void) { barrier(); - if (--suppress_int == 0 && pending_int) { + if (--suppress_int == 0 && pending_int) raise_interrupt(); - } } #if DEBUG_INTONOFF # define INT_ON do { \ @@ -711,7 +710,7 @@ int_on(void) #else # define INT_ON int_on() #endif -static IF_ASH_OPTIMIZE_FOR_SIZE(inline) void +static IF_NOT_ASH_OPTIMIZE_FOR_SIZE(inline) void force_int_on(void) { barrier(); @@ -10785,6 +10784,10 @@ preadfd(void) # endif reinit_unicode_for_ash(); again: +//BUG: not in INT_OFF/INT_ON section - SIGINT et al would longjmp out of read_line_input()! +//This would cause a memory leak in interactive shell +//(repeated internal allocations in read_line_input): +// (while kill -INT $$; do :; done) & nr = read_line_input(line_input_state, cmdedit_prompt, buf, IBUFSIZ); if (nr == 0) { /* ^C pressed, "convert" to SIGINT */ diff --git a/shell/shell_common.c b/shell/shell_common.c index 2e36d9208..13163acdf 100644 --- a/shell/shell_common.c +++ b/shell/shell_common.c @@ -196,6 +196,7 @@ shell_builtin_read(struct builtin_read_params *params) */ errno = 0; pfd[0].events = POLLIN; +//TODO race with a signal arriving just before the poll! if (poll(pfd, 1, timeout) <= 0) { /* timed out, or EINTR */ err = errno; -- cgit v1.2.1