On 29/09/20 14:55, Stefan Hajnoczi wrote:
> Block exports are used by softmmu, qemu-storage-daemon, and qemu-nbd.
> They are not used by other programs and are not otherwise needed in
> libblock.
>
> Undo the recent move of blockdev-nbd.c from blockdev_ss into block_ss.
> Since bdrv_close_all() (libblock) calls blk_exp_close_all()
> (libblockdev) a stub function is required..
>
> Make qemu-ndb.c use signal handling utility functions instead of
> duplicating the code. This helps because os-posix.c is in libblockdev
> and it depends on a qemu_system_killed() symbol that qemu-nbd.c lacks.
> Once we use the signal handling utility functions we also end up
> providing the necessary symbol.
>
> Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
> ---
> qemu-nbd.c | 21 +++++++++------------
> stubs/blk-exp-close-all.c | 7 +++++++
> block/export/meson.build | 4 ++--
> meson.build | 4 ++--
> nbd/meson.build | 2 ++
> stubs/meson.build | 1 +
> 6 files changed, 23 insertions(+), 16 deletions(-)
> create mode 100644 stubs/blk-exp-close-all.c
>
> diff --git a/qemu-nbd.c b/qemu-nbd.c
> index 6d7ac7490f..06774ca615 100644
> --- a/qemu-nbd.c
> +++ b/qemu-nbd.c
> @@ -25,6 +25,7 @@
> #include "qapi/error.h"
> #include "qemu/cutils.h"
> #include "sysemu/block-backend.h"
> +#include "sysemu/runstate.h" /* for qemu_system_killed() prototype */
> #include "block/block_int.h"
> #include "block/nbd.h"
> #include "qemu/main-loop.h"
> @@ -155,7 +156,11 @@ QEMU_COPYRIGHT "\n"
> }
>
> #if HAVE_NBD_DEVICE
> -static void termsig_handler(int signum)
> +/*
> + * The client thread uses SIGTERM to interrupt the server. A signal
> + * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
> + */
> +void qemu_system_killed(int signum, pid_t pid)
> {
> atomic_cmpxchg(&state, RUNNING, TERMINATE);
> qemu_notify_event();
> @@ -581,20 +586,12 @@ int main(int argc, char **argv)
> const char *pid_file_name = NULL;
> BlockExportOptions *export_opts;
>
> + os_setup_early_signal_handling();
> +
> #if HAVE_NBD_DEVICE
> - /* The client thread uses SIGTERM to interrupt the server. A signal
> - * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
> - */
> - struct sigaction sa_sigterm;
> - memset(&sa_sigterm, 0, sizeof(sa_sigterm));
> - sa_sigterm.sa_handler = termsig_handler;
> - sigaction(SIGTERM, &sa_sigterm, NULL);
> + os_setup_signal_handling();
> #endif /* HAVE_NBD_DEVICE */
>
> -#ifdef CONFIG_POSIX
> - signal(SIGPIPE, SIG_IGN);
> -#endif
> -
> socket_init();
> error_init(argv[0]);
> module_call_init(MODULE_INIT_TRACE);
> diff --git a/stubs/blk-exp-close-all.c b/stubs/blk-exp-close-all.c
> new file mode 100644
> index 0000000000..1c71316763
> --- /dev/null
> +++ b/stubs/blk-exp-close-all.c
> @@ -0,0 +1,7 @@
> +#include "qemu/osdep.h"
> +#include "block/export.h"
> +
> +/* Only used in programs that support block exports (libblockdev.fa) */
> +void blk_exp_close_all(void)
> +{
> +}
> diff --git a/block/export/meson.build b/block/export/meson.build
> index 469a7aa0f5..a2772a0dce 100644
> --- a/block/export/meson.build
> +++ b/block/export/meson.build
> @@ -1,2 +1,2 @@
> -block_ss.add(files('export.c'))
> -block_ss.add(when: 'CONFIG_VHOST_USER', if_true:
> files('vhost-user-blk-server.c'))
> +blockdev_ss.add(files('export.c'))
> +blockdev_ss.add(when: 'CONFIG_VHOST_USER', if_true:
> files('vhost-user-blk-server.c'))
> diff --git a/meson.build b/meson.build
> index 18d689b423..0e9528adab 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -835,7 +835,6 @@ subdir('dump')
>
> block_ss.add(files(
> 'block.c',
> - 'blockdev-nbd.c',
> 'blockjob.c',
> 'job.c',
> 'qemu-io-cmds.c',
> @@ -848,6 +847,7 @@ subdir('block')
>
> blockdev_ss.add(files(
> 'blockdev.c',
> + 'blockdev-nbd.c',
> 'iothread.c',
> 'job-qmp.c',
> ))
> @@ -1171,7 +1171,7 @@ if have_tools
> qemu_io = executable('qemu-io', files('qemu-io.c'),
> dependencies: [block, qemuutil], install: true)
> qemu_nbd = executable('qemu-nbd', files('qemu-nbd.c'),
> - dependencies: [block, qemuutil], install: true)
> + dependencies: [blockdev, qemuutil], install: true)
>
> subdir('storage-daemon')
> subdir('contrib/rdmacm-mux')
> diff --git a/nbd/meson.build b/nbd/meson.build
> index 0c00a776d3..2baaa36948 100644
> --- a/nbd/meson.build
> +++ b/nbd/meson.build
> @@ -1,5 +1,7 @@
> block_ss.add(files(
> 'client.c',
> 'common.c',
> +))
> +blockdev_ss.add(files(
> 'server.c',
> ))
> diff --git a/stubs/meson.build b/stubs/meson.build
> index e0b322bc28..0fdcf93c09 100644
> --- a/stubs/meson.build
> +++ b/stubs/meson.build
> @@ -1,6 +1,7 @@
> stub_ss.add(files('arch_type.c'))
> stub_ss.add(files('bdrv-next-monitor-owned.c'))
> stub_ss.add(files('blk-commit-all.c'))
> +stub_ss.add(files('blk-exp-close-all.c'))
> stub_ss.add(files('blockdev-close-all-bdrv-states.c'))
> stub_ss.add(files('change-state-handler.c'))
> stub_ss.add(files('clock-warp.c'))
>
Reviewed-by: Paolo Bonzini <pbonz...@redhat.com>
