Re: [PATCH 2/2] nbd: disable signals and forking on Windows builds

2020-08-25 Thread Daniel P . Berrangé
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
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Re: [PATCH 2/2] nbd: disable signals and forking on Windows builds

2020-08-24 Thread Thomas Huth

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

2020-08-24 Thread Eric Blake

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

2020-08-24 Thread Daniel P . Berrangé
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