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From: | Max Reitz |
Subject: | Re: [Qemu-devel] [PATCH v2 1/3] qemu-io: Add sigraise command |
Date: | Fri, 05 Dec 2014 11:07:18 +0100 |
User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 |
On 2014-12-05 at 10:52, Markus Armbruster wrote:
Max Reitz <address@hidden> 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 <address@hidden> --- 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
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