On 2014-12-05 at 10:52, Markus Armbruster wrote:
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.
Thus, -c abort is not always useful to simulate a qemu-io crash;
therefore, this patch adds a new sigraise command which allows to raise
any Unix signal.
Nitpick: signals are ISO C, not just UNIX.
Yes, but "Unix signal" is what the Wikipedia article is named, so... ;-)
Signed-off-by: Max Reitz <mre...@redhat.com>
---
qemu-io-cmds.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 46 insertions(+)
diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
index d94fb1e..942b694 100644
--- a/qemu-io-cmds.c
+++ b/qemu-io-cmds.c
@@ -2048,6 +2048,51 @@ static const cmdinfo_t abort_cmd = {
.oneline = "simulate a program crash using abort(3)",
};
+static void sigraise_help(void)
+{
+ printf(
+"\n"
+" raises the given Unix signal\n"
+"\n"
+" Example:\n"
+" 'sigraise 9' - raises SIGKILL\n"
Assumes SIGKILL is encoded as 9, which is traditionally the case, but
not actually mandated by POSIX.
Yes, I know. The best would be to parse the signal like kill(1) does,
but that would have been extra difficult and probably not worth the effort.
Furthermore, I know there is a song called "kill dash nine", so I
guessed it would be enough (at least it'll have to be enough for test
039, thanks to "_supported_os Linux").
You could avoid hardcoding 9 with
" 'sigraise %d' - raises SIGKILL\n"
with a SIGKILL as argument for %d.
Clever. Will do.
But then you'd have to face the fact that SIGKILL is POSIX, not ISO C.
The ISO C signals are SIGABRT, SIGFPE, SIGILL, SIGINT, SIGSEGV, SIGTERM.
Of these, SIGINT and SIGTERM don't dump core, in case you care.
Good to know. I guess I'll just go with SIGKILL anyway, it's ubiquitous
enough.
+"\n"
+" Invokes raise(signal), where \"signal\" is the mandatory integer argument\n"
+" given to sigraise.\n"
+"\n");
+}
+
+static int sigraise_f(BlockDriverState *bs, int argc, char **argv);
+
+static const cmdinfo_t sigraise_cmd = {
+ .name = "sigraise",
+ .cfunc = sigraise_f,
+ .argmin = 1,
+ .argmax = 1,
+ .flags = CMD_NOFILE_OK,
+ .args = "signal",
+ .oneline = "raises a Unix signal",
+ .help = sigraise_help,
+};
+
+static int sigraise_f(BlockDriverState *bs, int argc, char **argv)
+{
+ int sig = cvtnum(argv[1]);
+ if (sig < 0) {
+ printf("non-numeric signal number argument -- %s\n", argv[1]);
+ return 0;
+ }
+
+ /* Using raise() to kill this process does not necessarily flush all open
+ * streams. At least stdout and stderr (although the latter should be
+ * non-buffered anyway) should be flushed, though. */
+ fflush(stdout);
+ fflush(stderr);
+
+ raise(sig);
+ return 0;
+}
+
static void sleep_cb(void *opaque)
{
bool *expired = opaque;
@@ -2202,4 +2247,5 @@ static void __attribute((constructor))
init_qemuio_commands(void)
qemuio_add_command(&wait_break_cmd);
qemuio_add_command(&abort_cmd);
qemuio_add_command(&sleep_cmd);
+ qemuio_add_command(&sigraise_cmd);
}
Looks good otherwise.
Thanks :-)
Max
