diff mbox series

[PULL,12/13] qemu-nbd: Restore "qemu-nbd -v --fork" output

Message ID 20230908013535.990731-27-eblake@redhat.com
State New
Headers show
Series [PULL,01/13] qemu-iotests/197: use more generic commands for formats other than qcow2 | expand

Commit Message

Eric Blake Sept. 8, 2023, 1:35 a.m. UTC 
From: "Denis V. Lunev" <den@openvz.org>

Closing stderr earlier is good for daemonized qemu-nbd under ssh
earlier, but breaks the case where -v is being used to track what is
happening in the server, as in iotest 233.

When we know we are verbose, we should preserve original stderr and
restore it once the setup stage is done. This commit restores the
original behavior with -v option. In this case original output
inside the test is kept intact.

Reported-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Eric Blake <eblake@redhat.com>
CC: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
CC: Hanna Reitz <hreitz@redhat.com>
CC: Mike Maslenkin <mike.maslenkin@gmail.com>
Fixes: 5c56dd27a2 ("qemu-nbd: fix regression with qemu-nbd --fork run over ssh")
Message-ID: <20230906093210.339585-7-den@openvz.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Tested-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 qemu-nbd.c | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

Comments

Stefan Hajnoczi Sept. 8, 2023, 11:03 a.m. UTC | #1 
Please resolve the following CI failure:

https://gitlab.com/qemu-project/qemu/-/jobs/5045998355

ninja: job failed: cc -m64 -mcx16 -Iqemu-nbd.p -I. -I.. -Iqapi -Itrace
-Iui -Iui/shader -I/usr/include/p11-kit-1 -I/usr/include/glib-2.0
-I/usr/lib/glib-2.0/include -fdiagnostics-color=auto -Wall
-Winvalid-pch -Werror -std=gnu11 -O2 -g -fstack-protector-strong
-U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -Wundef -Wwrite-strings
-Wmissing-prototypes -Wstrict-prototypes -Wredundant-decls
-Wold-style-declaration -Wold-style-definition -Wtype-limits
-Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers
-Wempty-body -Wnested-externs -Wendif-labels -Wexpansion-to-defined
-Wimplicit-fallthrough=2 -Wmissing-format-attribute
-Wno-missing-include-dirs -Wno-shift-negative-value -Wno-psabi
-isystem /builds/qemu-project/qemu/linux-headers -isystem
linux-headers -iquote . -iquote /builds/qemu-project/qemu -iquote
/builds/qemu-project/qemu/include -iquote
/builds/qemu-project/qemu/host/include/x86_64 -iquote
/builds/qemu-project/qemu/host/include/generic -iquote
/builds/qemu-project/qemu/tcg/i386 -pthread -D_GNU_SOURCE
-D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -fno-strict-aliasing
-fno-common -fwrapv -fPIE -MD -MQ qemu-nbd.p/qemu-nbd.c.o -MF
qemu-nbd.p/qemu-nbd.c.o.d -o qemu-nbd.p/qemu-nbd.c.o -c ../qemu-nbd.c
In file included from /usr/include/fortify/stdio.h:23,
from ../include/qemu/osdep.h:110,
from ../qemu-nbd.c:19:
../qemu-nbd.c: In function 'nbd_client_thread':
../qemu-nbd.c:340:39: error: expected identifier before '(' token
340 | nbd_client_release_pipe(opts->stderr);
| ^~~~~~
../qemu-nbd.c: In function 'main':
../qemu-nbd.c:605:10: error: expected identifier before '(' token
605 | .stderr = STDOUT_FILENO,
| ^~~~~~
../qemu-nbd.c:962:22: error: expected identifier before '(' token
962 | opts.stderr = dup(STDERR_FILENO);
| ^~~~~~
../qemu-nbd.c:963:26: error: expected identifier before '(' token
963 | if (opts.stderr < 0) {
| ^~~~~~
../qemu-nbd.c:1200:38: error: expected identifier before '(' token
1200 | nbd_client_release_pipe(opts.stderr);
| ^~~~~~

On Thu, 7 Sept 2023 at 21:37, Eric Blake <eblake@redhat.com> wrote:
>
> From: "Denis V. Lunev" <den@openvz.org>
>
> Closing stderr earlier is good for daemonized qemu-nbd under ssh
> earlier, but breaks the case where -v is being used to track what is
> happening in the server, as in iotest 233.
>
> When we know we are verbose, we should preserve original stderr and
> restore it once the setup stage is done. This commit restores the
> original behavior with -v option. In this case original output
> inside the test is kept intact.
>
> Reported-by: Kevin Wolf <kwolf@redhat.com>
> Signed-off-by: Denis V. Lunev <den@openvz.org>
> CC: Eric Blake <eblake@redhat.com>
> CC: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
> CC: Hanna Reitz <hreitz@redhat.com>
> CC: Mike Maslenkin <mike.maslenkin@gmail.com>
> Fixes: 5c56dd27a2 ("qemu-nbd: fix regression with qemu-nbd --fork run over ssh")
> Message-ID: <20230906093210.339585-7-den@openvz.org>
> Reviewed-by: Eric Blake <eblake@redhat.com>
> Tested-by: Eric Blake <eblake@redhat.com>
> Signed-off-by: Eric Blake <eblake@redhat.com>
> ---
>  qemu-nbd.c | 24 ++++++++++++++++++++----
>  1 file changed, 20 insertions(+), 4 deletions(-)
>
> diff --git a/qemu-nbd.c b/qemu-nbd.c
> index 7c4e22def17..1cdc41ed292 100644
> --- a/qemu-nbd.c
> +++ b/qemu-nbd.c
> @@ -255,18 +255,23 @@ struct NbdClientOpts {
>      char *device;
>      char *srcpath;
>      SocketAddress *saddr;
> +    int stderr;
>      bool fork_process;
>      bool verbose;
>  };
>
> -static void nbd_client_release_pipe(void)
> +static void nbd_client_release_pipe(int old_stderr)
>  {
>      /* Close stderr so that the qemu-nbd process exits.  */
> -    if (dup2(STDOUT_FILENO, STDERR_FILENO) < 0) {
> +    if (dup2(old_stderr, STDERR_FILENO) < 0) {
>          error_report("Could not release pipe to parent: %s",
>                       strerror(errno));
>          exit(EXIT_FAILURE);
>      }
> +    if (old_stderr != STDOUT_FILENO && close(old_stderr) < 0) {
> +        error_report("Could not release qemu-nbd: %s", strerror(errno));
> +        exit(EXIT_FAILURE);
> +    }
>  }
>
>  #if HAVE_NBD_DEVICE
> @@ -332,7 +337,7 @@ static void *nbd_client_thread(void *arg)
>          fprintf(stderr, "NBD device %s is now connected to %s\n",
>                  opts->device, opts->srcpath);
>      } else {
> -        nbd_client_release_pipe();
> +        nbd_client_release_pipe(opts->stderr);
>      }
>
>      if (nbd_client(fd) < 0) {
> @@ -597,6 +602,7 @@ int main(int argc, char **argv)
>          .device = NULL,
>          .srcpath = NULL,
>          .saddr = NULL,
> +        .stderr = STDOUT_FILENO,
>      };
>
>  #ifdef CONFIG_POSIX
> @@ -951,6 +957,16 @@ int main(int argc, char **argv)
>
>              close(stderr_fd[0]);
>
> +            /* Remember parent's stderr if we will be restoring it. */
> +            if (opts.verbose /* fork_process is set */) {
> +                opts.stderr = dup(STDERR_FILENO);
> +                if (opts.stderr < 0) {
> +                    error_report("Could not dup original stderr: %s",
> +                                 strerror(errno));
> +                    exit(EXIT_FAILURE);
> +                }
> +            }
> +
>              ret = qemu_daemon(1, 0);
>              saved_errno = errno;    /* dup2 will overwrite error below */
>
> @@ -1181,7 +1197,7 @@ int main(int argc, char **argv)
>      }
>
>      if (opts.fork_process) {
> -        nbd_client_release_pipe();
> +        nbd_client_release_pipe(opts.stderr);
>      }
>
>      state = RUNNING;
> --
> 2.41.0
>
>
Denis V. Lunev Sept. 8, 2023, 11:24 a.m. UTC | #2 
On 9/8/23 13:03, Stefan Hajnoczi wrote:
> Please resolve the following CI failure:
>
> https://gitlab.com/qemu-project/qemu/-/jobs/5045998355
>
> ninja: job failed: cc -m64 -mcx16 -Iqemu-nbd.p -I. -I.. -Iqapi -Itrace
> -Iui -Iui/shader -I/usr/include/p11-kit-1 -I/usr/include/glib-2.0
> -I/usr/lib/glib-2.0/include -fdiagnostics-color=auto -Wall
> -Winvalid-pch -Werror -std=gnu11 -O2 -g -fstack-protector-strong
> -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -Wundef -Wwrite-strings
> -Wmissing-prototypes -Wstrict-prototypes -Wredundant-decls
> -Wold-style-declaration -Wold-style-definition -Wtype-limits
> -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers
> -Wempty-body -Wnested-externs -Wendif-labels -Wexpansion-to-defined
> -Wimplicit-fallthrough=2 -Wmissing-format-attribute
> -Wno-missing-include-dirs -Wno-shift-negative-value -Wno-psabi
> -isystem /builds/qemu-project/qemu/linux-headers -isystem
> linux-headers -iquote . -iquote /builds/qemu-project/qemu -iquote
> /builds/qemu-project/qemu/include -iquote
> /builds/qemu-project/qemu/host/include/x86_64 -iquote
> /builds/qemu-project/qemu/host/include/generic -iquote
> /builds/qemu-project/qemu/tcg/i386 -pthread -D_GNU_SOURCE
> -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -fno-strict-aliasing
> -fno-common -fwrapv -fPIE -MD -MQ qemu-nbd.p/qemu-nbd.c.o -MF
> qemu-nbd.p/qemu-nbd.c.o.d -o qemu-nbd.p/qemu-nbd.c.o -c ../qemu-nbd.c
> In file included from /usr/include/fortify/stdio.h:23,
> from ../include/qemu/osdep.h:110,
> from ../qemu-nbd.c:19:
> ../qemu-nbd.c: In function 'nbd_client_thread':
> ../qemu-nbd.c:340:39: error: expected identifier before '(' token
> 340 | nbd_client_release_pipe(opts->stderr);
> | ^~~~~~
> ../qemu-nbd.c: In function 'main':
> ../qemu-nbd.c:605:10: error: expected identifier before '(' token
> 605 | .stderr = STDOUT_FILENO,
> | ^~~~~~
> ../qemu-nbd.c:962:22: error: expected identifier before '(' token
> 962 | opts.stderr = dup(STDERR_FILENO);
> | ^~~~~~
> ../qemu-nbd.c:963:26: error: expected identifier before '(' token
> 963 | if (opts.stderr < 0) {
> | ^~~~~~
> ../qemu-nbd.c:1200:38: error: expected identifier before '(' token
> 1200 | nbd_client_release_pipe(opts.stderr);
> | ^~~~~~

quite interesting and surprising. Tried to reproduce with

./configure 
--target-list=avr-softmmu,loongarch64-softmmu,mips64-softmmu,mipsel-softmmu 
--enable-werror --disable-docs --enable-fdt=system

locally but without success - the code is compiled fine.

Is there any way to get into the Jenkins environment?

Den
Denis V. Lunev Sept. 8, 2023, 11:42 a.m. UTC | #3 
On 9/8/23 13:24, Denis V. Lunev wrote:
> On 9/8/23 13:03, Stefan Hajnoczi wrote:
>> Please resolve the following CI failure:
>>
>> https://gitlab.com/qemu-project/qemu/-/jobs/5045998355
>>
>> ninja: job failed: cc -m64 -mcx16 -Iqemu-nbd.p -I. -I.. -Iqapi -Itrace
>> -Iui -Iui/shader -I/usr/include/p11-kit-1 -I/usr/include/glib-2.0
>> -I/usr/lib/glib-2.0/include -fdiagnostics-color=auto -Wall
>> -Winvalid-pch -Werror -std=gnu11 -O2 -g -fstack-protector-strong
>> -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -Wundef -Wwrite-strings
>> -Wmissing-prototypes -Wstrict-prototypes -Wredundant-decls
>> -Wold-style-declaration -Wold-style-definition -Wtype-limits
>> -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers
>> -Wempty-body -Wnested-externs -Wendif-labels -Wexpansion-to-defined
>> -Wimplicit-fallthrough=2 -Wmissing-format-attribute
>> -Wno-missing-include-dirs -Wno-shift-negative-value -Wno-psabi
>> -isystem /builds/qemu-project/qemu/linux-headers -isystem
>> linux-headers -iquote . -iquote /builds/qemu-project/qemu -iquote
>> /builds/qemu-project/qemu/include -iquote
>> /builds/qemu-project/qemu/host/include/x86_64 -iquote
>> /builds/qemu-project/qemu/host/include/generic -iquote
>> /builds/qemu-project/qemu/tcg/i386 -pthread -D_GNU_SOURCE
>> -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -fno-strict-aliasing
>> -fno-common -fwrapv -fPIE -MD -MQ qemu-nbd.p/qemu-nbd.c.o -MF
>> qemu-nbd.p/qemu-nbd.c.o.d -o qemu-nbd.p/qemu-nbd.c.o -c ../qemu-nbd.c
>> In file included from /usr/include/fortify/stdio.h:23,
>> from ../include/qemu/osdep.h:110,
>> from ../qemu-nbd.c:19:
>> ../qemu-nbd.c: In function 'nbd_client_thread':
>> ../qemu-nbd.c:340:39: error: expected identifier before '(' token
>> 340 | nbd_client_release_pipe(opts->stderr);
>> | ^~~~~~
>> ../qemu-nbd.c: In function 'main':
>> ../qemu-nbd.c:605:10: error: expected identifier before '(' token
>> 605 | .stderr = STDOUT_FILENO,
>> | ^~~~~~
>> ../qemu-nbd.c:962:22: error: expected identifier before '(' token
>> 962 | opts.stderr = dup(STDERR_FILENO);
>> | ^~~~~~
>> ../qemu-nbd.c:963:26: error: expected identifier before '(' token
>> 963 | if (opts.stderr < 0) {
>> | ^~~~~~
>> ../qemu-nbd.c:1200:38: error: expected identifier before '(' token
>> 1200 | nbd_client_release_pipe(opts.stderr);
>> | ^~~~~~
>
> quite interesting and surprising. Tried to reproduce with
>
> ./configure 
> --target-list=avr-softmmu,loongarch64-softmmu,mips64-softmmu,mipsel-softmmu 
> --enable-werror --disable-docs --enable-fdt=system
>
> locally but without success - the code is compiled fine.
>
> Is there any way to get into the Jenkins environment?
>
> Den
The only possible reason I could imagine is that 'stderr'
word is defined under by pre-processor.

Den
Eric Blake Sept. 8, 2023, 12:09 p.m. UTC | #4 
On Fri, Sep 08, 2023 at 01:42:00PM +0200, Denis V. Lunev wrote:
> On 9/8/23 13:24, Denis V. Lunev wrote:
> > On 9/8/23 13:03, Stefan Hajnoczi wrote:
> > > Please resolve the following CI failure:
> > > 
> > > https://gitlab.com/qemu-project/qemu/-/jobs/5045998355
> > > 
> > > ../qemu-nbd.c: In function 'nbd_client_thread':
> > > ../qemu-nbd.c:340:39: error: expected identifier before '(' token
> > > 340 | nbd_client_release_pipe(opts->stderr);
> > > | ^~~~~~

> The only possible reason I could imagine is that 'stderr'
> word is defined under by pre-processor.

Indeed, that is a common implementation; the obvious fix is to use a
different name.  v2 coming up with that change made.
diff mbox series

Patch

diff --git a/qemu-nbd.c b/qemu-nbd.c
index 7c4e22def17..1cdc41ed292 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -255,18 +255,23 @@  struct NbdClientOpts {
     char *device;
     char *srcpath;
     SocketAddress *saddr;
+    int stderr;
     bool fork_process;
     bool verbose;
 };

-static void nbd_client_release_pipe(void)
+static void nbd_client_release_pipe(int old_stderr)
 {
     /* Close stderr so that the qemu-nbd process exits.  */
-    if (dup2(STDOUT_FILENO, STDERR_FILENO) < 0) {
+    if (dup2(old_stderr, STDERR_FILENO) < 0) {
         error_report("Could not release pipe to parent: %s",
                      strerror(errno));
         exit(EXIT_FAILURE);
     }
+    if (old_stderr != STDOUT_FILENO && close(old_stderr) < 0) {
+        error_report("Could not release qemu-nbd: %s", strerror(errno));
+        exit(EXIT_FAILURE);
+    }
 }

 #if HAVE_NBD_DEVICE
@@ -332,7 +337,7 @@  static void *nbd_client_thread(void *arg)
         fprintf(stderr, "NBD device %s is now connected to %s\n",
                 opts->device, opts->srcpath);
     } else {
-        nbd_client_release_pipe();
+        nbd_client_release_pipe(opts->stderr);
     }

     if (nbd_client(fd) < 0) {
@@ -597,6 +602,7 @@  int main(int argc, char **argv)
         .device = NULL,
         .srcpath = NULL,
         .saddr = NULL,
+        .stderr = STDOUT_FILENO,
     };

 #ifdef CONFIG_POSIX
@@ -951,6 +957,16 @@  int main(int argc, char **argv)

             close(stderr_fd[0]);

+            /* Remember parent's stderr if we will be restoring it. */
+            if (opts.verbose /* fork_process is set */) {
+                opts.stderr = dup(STDERR_FILENO);
+                if (opts.stderr < 0) {
+                    error_report("Could not dup original stderr: %s",
+                                 strerror(errno));
+                    exit(EXIT_FAILURE);
+                }
+            }
+
             ret = qemu_daemon(1, 0);
             saved_errno = errno;    /* dup2 will overwrite error below */

@@ -1181,7 +1197,7 @@  int main(int argc, char **argv)
     }

     if (opts.fork_process) {
-        nbd_client_release_pipe();
+        nbd_client_release_pipe(opts.stderr);
     }

     state = RUNNING;