Re: [PATCH 2/2] nbd: disable signals and forking on Windows builds
On Mon, Aug 24, 2020 at 12:12:53PM -0500, Eric Blake wrote:
> On 8/24/20 12:02 PM, Daniel P. Berrangé wrote:
> > Disabling these parts are sufficient to get the qemu-nbd program
> > compiling in a Windows build.
> >
> > Signed-off-by: Daniel P. Berrangé
> > ---
> > meson.build | 7 ++-
> > qemu-nbd.c | 10 +-
> > 2 files changed, 11 insertions(+), 6 deletions(-)
>
> Feels a bit hacky at what it supports, but certainly better than nothing ;)
>
> >
> > diff --git a/meson.build b/meson.build
> > index df5bf728b5..1071871605 100644
> > --- a/meson.build
> > +++ b/meson.build
> > @@ -1074,12 +1074,9 @@ if have_tools
> >dependencies: [authz, block, crypto, io, qom, qemuutil],
> > install: true)
> > qemu_io = executable('qemu-io', files('qemu-io.c'),
> >dependencies: [block, qemuutil], install: true)
> > - qemu_block_tools += [qemu_img, qemu_io]
> > - if targetos == 'linux' or targetos == 'sunos' or targetos.endswith('bsd')
> > -qemu_nbd = executable('qemu-nbd', files('qemu-nbd.c'),
> > + qemu_nbd = executable('qemu-nbd', files('qemu-nbd.c'),
> > dependencies: [block, qemuutil], install: true)
>
> Conflicts with this patch:
> https://lists.gnu.org/archive/html/qemu-devel/2020-08/msg05546.html
>
> but this one gets rid of the need for that one.
>
> > -qemu_block_tools += [qemu_nbd]
> > - endif
> > + qemu_block_tools += [qemu_img, qemu_io, qemu_nbd]
> > subdir('storage-daemon')
> > subdir('contrib/rdmacm-mux')
> > diff --git a/qemu-nbd.c b/qemu-nbd.c
> > index b102874f0f..c6fd6524d3 100644
> > --- a/qemu-nbd.c
> > +++ b/qemu-nbd.c
> > @@ -155,12 +155,13 @@ QEMU_COPYRIGHT "\n"
> > , name);
> > }
> > +#ifndef WIN32
> > static void termsig_handler(int signum)
> > {
> > atomic_cmpxchg(, RUNNING, TERMINATE);
> > qemu_notify_event();
> > }
> > -
> > +#endif
>
> How does one terminate a long-running server on Windows if there is no
> SIGTERM handler? I guess Ctrl-C does something, but without the state
> notification from a signal handler, you are getting less-clean shutdowns,
> which may explain the hangs you were seeing in testing? But incremental
> progress is fine, and I see no reason to not take this patch as-is.
The hangs occurred even with windows client/ native server, just less
frequently so don't think it is related.
Re-reading the code I notice this SIGTERM handler is only there for
the NBD device client thread, so we should skip it if that is not
installed.
Ctrl-C does SIGINT, so that's unrelated to the SIGTERM handler.
>
> Reviewed-by: Eric Blake
>
> I'm happy to queue this series through my NBD tree.
I'll post a v2
Regards,
Daniel
--
|: https://berrange.com -o-https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o-https://fstop138.berrange.com :|
|: https://entangle-photo.org-o-https://www.instagram.com/dberrange :|
Re: [PATCH 2/2] nbd: disable signals and forking on Windows builds
On 24/08/2020 19.02, Daniel P. Berrangé wrote:
Disabling these parts are sufficient to get the qemu-nbd program
compiling in a Windows build.
Maybe add:
"This also enables compilation of qemu-nbd on macOS again (which got
disabled by accident during the conversion to the meson build system)"
Signed-off-by: Daniel P. Berrangé
---
meson.build | 7 ++-
qemu-nbd.c | 10 +-
2 files changed, 11 insertions(+), 6 deletions(-)
diff --git a/meson.build b/meson.build
index df5bf728b5..1071871605 100644
--- a/meson.build
+++ b/meson.build
@@ -1074,12 +1074,9 @@ if have_tools
dependencies: [authz, block, crypto, io, qom, qemuutil],
install: true)
qemu_io = executable('qemu-io', files('qemu-io.c'),
dependencies: [block, qemuutil], install: true)
- qemu_block_tools += [qemu_img, qemu_io]
- if targetos == 'linux' or targetos == 'sunos' or targetos.endswith('bsd')
-qemu_nbd = executable('qemu-nbd', files('qemu-nbd.c'),
+ qemu_nbd = executable('qemu-nbd', files('qemu-nbd.c'),
dependencies: [block, qemuutil], install: true)
-qemu_block_tools += [qemu_nbd]
- endif
+ qemu_block_tools += [qemu_img, qemu_io, qemu_nbd]
subdir('storage-daemon')
subdir('contrib/rdmacm-mux')
diff --git a/qemu-nbd.c b/qemu-nbd.c
index b102874f0f..c6fd6524d3 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -155,12 +155,13 @@ QEMU_COPYRIGHT "\n"
, name);
}
+#ifndef WIN32
static void termsig_handler(int signum)
{
atomic_cmpxchg(, RUNNING, TERMINATE);
qemu_notify_event();
}
-
+#endif
static int qemu_nbd_client_list(SocketAddress *saddr, QCryptoTLSCreds *tls,
const char *hostname)
@@ -587,6 +588,7 @@ int main(int argc, char **argv)
unsigned socket_activation;
const char *pid_file_name = NULL;
+#ifndef WIN32
/* The client thread uses SIGTERM to interrupt the server. A signal
* handler ensures that "qemu-nbd -v -c" exits with a nice status code.
*/
@@ -594,6 +596,7 @@ int main(int argc, char **argv)
memset(_sigterm, 0, sizeof(sa_sigterm));
sa_sigterm.sa_handler = termsig_handler;
sigaction(SIGTERM, _sigterm, NULL);
+#endif
#ifdef CONFIG_POSIX
I wonder why the CONFIG_POSIX does not simply start earlier here ... I
think you could replace your #ifndef WIN32 with #ifdef CONFIG_POSIX that
way?
signal(SIGPIPE, SIG_IGN);
@@ -896,6 +899,7 @@ int main(int argc, char **argv)
#endif
if ((device && !verbose) || fork_process) {
+#ifndef WIN32
int stderr_fd[2];
pid_t pid;
int ret;
@@ -959,6 +963,10 @@ int main(int argc, char **argv)
*/
exit(errors);
}
+#else /* WIN32 */
+error_report("Unable to fork into background on Windows hosts");
+exit(EXIT_FAILURE);
+#endif /* WIN32 */
}
if (device != NULL && sockpath == NULL) {
Thomas
Re: [PATCH 2/2] nbd: disable signals and forking on Windows builds
On 8/24/20 12:02 PM, Daniel P. Berrangé wrote:
Disabling these parts are sufficient to get the qemu-nbd program
compiling in a Windows build.
Signed-off-by: Daniel P. Berrangé
---
meson.build | 7 ++-
qemu-nbd.c | 10 +-
2 files changed, 11 insertions(+), 6 deletions(-)
Feels a bit hacky at what it supports, but certainly better than nothing ;)
diff --git a/meson.build b/meson.build
index df5bf728b5..1071871605 100644
--- a/meson.build
+++ b/meson.build
@@ -1074,12 +1074,9 @@ if have_tools
dependencies: [authz, block, crypto, io, qom, qemuutil],
install: true)
qemu_io = executable('qemu-io', files('qemu-io.c'),
dependencies: [block, qemuutil], install: true)
- qemu_block_tools += [qemu_img, qemu_io]
- if targetos == 'linux' or targetos == 'sunos' or targetos.endswith('bsd')
-qemu_nbd = executable('qemu-nbd', files('qemu-nbd.c'),
+ qemu_nbd = executable('qemu-nbd', files('qemu-nbd.c'),
dependencies: [block, qemuutil], install: true)
Conflicts with this patch:
https://lists.gnu.org/archive/html/qemu-devel/2020-08/msg05546.html
but this one gets rid of the need for that one.
-qemu_block_tools += [qemu_nbd]
- endif
+ qemu_block_tools += [qemu_img, qemu_io, qemu_nbd]
subdir('storage-daemon')
subdir('contrib/rdmacm-mux')
diff --git a/qemu-nbd.c b/qemu-nbd.c
index b102874f0f..c6fd6524d3 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -155,12 +155,13 @@ QEMU_COPYRIGHT "\n"
, name);
}
+#ifndef WIN32
static void termsig_handler(int signum)
{
atomic_cmpxchg(, RUNNING, TERMINATE);
qemu_notify_event();
}
-
+#endif
How does one terminate a long-running server on Windows if there is no
SIGTERM handler? I guess Ctrl-C does something, but without the state
notification from a signal handler, you are getting less-clean
shutdowns, which may explain the hangs you were seeing in testing? But
incremental progress is fine, and I see no reason to not take this patch
as-is.
Reviewed-by: Eric Blake
I'm happy to queue this series through my NBD tree.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org
[PATCH 2/2] nbd: disable signals and forking on Windows builds
Disabling these parts are sufficient to get the qemu-nbd program
compiling in a Windows build.
Signed-off-by: Daniel P. Berrangé
---
meson.build | 7 ++-
qemu-nbd.c | 10 +-
2 files changed, 11 insertions(+), 6 deletions(-)
diff --git a/meson.build b/meson.build
index df5bf728b5..1071871605 100644
--- a/meson.build
+++ b/meson.build
@@ -1074,12 +1074,9 @@ if have_tools
dependencies: [authz, block, crypto, io, qom, qemuutil], install:
true)
qemu_io = executable('qemu-io', files('qemu-io.c'),
dependencies: [block, qemuutil], install: true)
- qemu_block_tools += [qemu_img, qemu_io]
- if targetos == 'linux' or targetos == 'sunos' or targetos.endswith('bsd')
-qemu_nbd = executable('qemu-nbd', files('qemu-nbd.c'),
+ qemu_nbd = executable('qemu-nbd', files('qemu-nbd.c'),
dependencies: [block, qemuutil], install: true)
-qemu_block_tools += [qemu_nbd]
- endif
+ qemu_block_tools += [qemu_img, qemu_io, qemu_nbd]
subdir('storage-daemon')
subdir('contrib/rdmacm-mux')
diff --git a/qemu-nbd.c b/qemu-nbd.c
index b102874f0f..c6fd6524d3 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -155,12 +155,13 @@ QEMU_COPYRIGHT "\n"
, name);
}
+#ifndef WIN32
static void termsig_handler(int signum)
{
atomic_cmpxchg(, RUNNING, TERMINATE);
qemu_notify_event();
}
-
+#endif
static int qemu_nbd_client_list(SocketAddress *saddr, QCryptoTLSCreds *tls,
const char *hostname)
@@ -587,6 +588,7 @@ int main(int argc, char **argv)
unsigned socket_activation;
const char *pid_file_name = NULL;
+#ifndef WIN32
/* The client thread uses SIGTERM to interrupt the server. A signal
* handler ensures that "qemu-nbd -v -c" exits with a nice status code.
*/
@@ -594,6 +596,7 @@ int main(int argc, char **argv)
memset(_sigterm, 0, sizeof(sa_sigterm));
sa_sigterm.sa_handler = termsig_handler;
sigaction(SIGTERM, _sigterm, NULL);
+#endif
#ifdef CONFIG_POSIX
signal(SIGPIPE, SIG_IGN);
@@ -896,6 +899,7 @@ int main(int argc, char **argv)
#endif
if ((device && !verbose) || fork_process) {
+#ifndef WIN32
int stderr_fd[2];
pid_t pid;
int ret;
@@ -959,6 +963,10 @@ int main(int argc, char **argv)
*/
exit(errors);
}
+#else /* WIN32 */
+error_report("Unable to fork into background on Windows hosts");
+exit(EXIT_FAILURE);
+#endif /* WIN32 */
}
if (device != NULL && sockpath == NULL) {
--
2.26.2
