block: move block exports to libblockdev

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-nbd.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 <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20200929125516.186715-4-stefanha@redhat.com
[Fixed s/ndb/nbd/ typo in commit description as suggested by Eric Blake
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Stefan Hajnoczi
2020-09-29 13:55:15 +01:00
parent 4fb9071f65
commit cbc20bfb8f
6 changed files with 22 additions and 17 deletions

View File

@ -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"
}
#ifdef CONFIG_POSIX
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)
{
qatomic_cmpxchg(&state, RUNNING, TERMINATE);
qemu_notify_event();
@ -582,18 +587,8 @@ int main(int argc, char **argv)
BlockExportOptions *export_opts;
#ifdef CONFIG_POSIX
/*
* Exit gracefully on various signals, which includes SIGTERM used
* by 'qemu-nbd -v -c'.
*/
struct sigaction sa_sigterm;
memset(&sa_sigterm, 0, sizeof(sa_sigterm));
sa_sigterm.sa_handler = termsig_handler;
sigaction(SIGTERM, &sa_sigterm, NULL);
sigaction(SIGINT, &sa_sigterm, NULL);
sigaction(SIGHUP, &sa_sigterm, NULL);
signal(SIGPIPE, SIG_IGN);
os_setup_early_signal_handling();
os_setup_signal_handling();
#endif
socket_init();