Max Reitz <mre...@redhat.com> writes:
> abort() has the sometimes undesirable side-effect of generating a core
> dump. If that is not needed, SIGKILL has the same effect of abruptly
> crash qemu; without a core dump.
>
> Therefore, this patch allows to use the qemu-io abort command to raise
> any signal.
>
> Signed-off-by: Max Reitz <mre...@redhat.com>
> ---
> qemu-io-cmds.c | 59
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++---
> 1 file changed, 56 insertions(+), 3 deletions(-)
>
> diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
> index d94fb1e..5d39cf4 100644
> --- a/qemu-io-cmds.c
> +++ b/qemu-io-cmds.c
> @@ -2036,18 +2036,71 @@ static const cmdinfo_t wait_break_cmd = {
> .oneline = "waits for the suspension of a request",
> };
>
> -static int abort_f(BlockDriverState *bs, int argc, char **argv)
> +
> +static void abort_help(void)
> {
> - abort();
> + printf(
> +"\n"
> +" simulates a program crash\n"
> +"\n"
> +" Invokes abort(), or raise(signal) if a signal number is specified.\n"
> +" -S, -- number of the signal to raise()\n"
> +"\n");
> }
>
> +static int abort_f(BlockDriverState *bs, int argc, char **argv);
> +
> static const cmdinfo_t abort_cmd = {
> .name = "abort",
> .cfunc = abort_f,
> + .argmin = 0,
> + .argmax = 2,
> .flags = CMD_NOFILE_OK,
> - .oneline = "simulate a program crash using abort(3)",
> + .args = "[-S signal]",
> + .oneline = "simulate a program crash",
> + .help = abort_help,
> };
This overloads the abort command with a kill command.
Do we really need a way to send arbitrary signals? If yes, shouldn't we
call it "kill" rather than "abort"?
I suspect fooling around with signals isn't necessary, and a simple
exit(1) would do.
>
> +static int abort_f(BlockDriverState *bs, int argc, char **argv)
> +{
> + int c;
> + int sig = -1;
> +
> + while ((c = getopt(argc, argv, "S:")) != EOF) {
> + switch (c) {
> + case 'S':
> + sig = cvtnum(optarg);
> + if (sig < 0) {
> + printf("non-numeric signal number argument -- %s\n",
> optarg);
> + return 0;
> + }
> + break;
> +
> + default:
> + return qemuio_command_usage(&abort_cmd);
> + }
> + }
> +
> + if (optind != argc) {
> + return qemuio_command_usage(&abort_cmd);
> + }
> +
> + if (sig < 0) {
> + abort();
> + } else {
> + /* While abort() does flush all open streams, using raise() to kill
> this
> + * process does not necessarily. At least stdout and stderr (although
> + * the latter should be non-buffered anyway) should be flushed,
> though.
> + */
> + fflush(stdout);
> + fflush(stderr);
Without -S, we flush all streams. With -S, we flush only stdout and
stderr. The inconsistency is ugly. Could be avoided with fcloseall(),
except it's a GNU extension. Or drop the non-signal path entirely, and
raise(SIGABRT) instead of abort().
> +
> + raise(sig);
> + /* raise() may return */
> + return 0;
> + }
> +}
> +
> static void sleep_cb(void *opaque)
> {
> bool *expired = opaque;
