f37afb5ab1
Error propagation is already there for socket backends. Add it to other
protocols, simplifying code that tests for errors that will never happen.
With all protocols understanding Error, the code can be simplified
further by removing the return value.
Unfortunately, the quality of error messages varies depending
on where the error is detected, because no Error is passed to the
NonBlockingConnectHandler. Thus, the exact error message still cannot
be sent to the user if the OS reports it asynchronously via SO_ERROR.
If NonBlockingConnectHandler received an Error**, we could for
example report the error class and/or message via a new field of the
query-migration command even if it is reported asynchronously.
Before:
(qemu) migrate fd:ffff
migrate: An undefined error has occurred
(qemu) info migrate
(qemu)
After:
(qemu) migrate fd:ffff
migrate: File descriptor named 'ffff' has not been found
(qemu) info migrate
capabilities: xbzrle: off
Migration status: failed
total time: 0 milliseconds
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
118 lines
2.6 KiB
C
118 lines
2.6 KiB
C
/*
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* QEMU live migration via generic fd
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*
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* Copyright Red Hat, Inc. 2009
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*
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* Authors:
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* Chris Lalancette <clalance@redhat.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*
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* Contributions after 2012-01-13 are licensed under the terms of the
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* GNU GPL, version 2 or (at your option) any later version.
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*/
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#include "qemu-common.h"
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#include "qemu_socket.h"
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#include "migration.h"
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#include "monitor.h"
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#include "qemu-char.h"
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#include "buffered_file.h"
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#include "block.h"
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#include "qemu_socket.h"
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//#define DEBUG_MIGRATION_FD
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#ifdef DEBUG_MIGRATION_FD
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#define DPRINTF(fmt, ...) \
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do { printf("migration-fd: " fmt, ## __VA_ARGS__); } while (0)
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#else
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#define DPRINTF(fmt, ...) \
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do { } while (0)
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#endif
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static int fd_errno(MigrationState *s)
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{
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return errno;
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}
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static int fd_write(MigrationState *s, const void * buf, size_t size)
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{
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return write(s->fd, buf, size);
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}
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static int fd_close(MigrationState *s)
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{
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struct stat st;
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int ret;
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DPRINTF("fd_close\n");
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if (s->fd != -1) {
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ret = fstat(s->fd, &st);
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if (ret == 0 && S_ISREG(st.st_mode)) {
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/*
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* If the file handle is a regular file make sure the
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* data is flushed to disk before signaling success.
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*/
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ret = fsync(s->fd);
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if (ret != 0) {
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ret = -errno;
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perror("migration-fd: fsync");
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return ret;
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}
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}
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ret = close(s->fd);
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s->fd = -1;
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if (ret != 0) {
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ret = -errno;
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perror("migration-fd: close");
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return ret;
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}
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}
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return 0;
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}
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void fd_start_outgoing_migration(MigrationState *s, const char *fdname, Error **errp)
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{
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s->fd = monitor_get_fd(cur_mon, fdname, errp);
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if (s->fd == -1) {
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return;
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}
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fcntl(s->fd, F_SETFL, O_NONBLOCK);
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s->get_error = fd_errno;
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s->write = fd_write;
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s->close = fd_close;
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migrate_fd_connect(s);
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}
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static void fd_accept_incoming_migration(void *opaque)
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{
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QEMUFile *f = opaque;
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process_incoming_migration(f);
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qemu_set_fd_handler2(qemu_stdio_fd(f), NULL, NULL, NULL, NULL);
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qemu_fclose(f);
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}
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int fd_start_incoming_migration(const char *infd)
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{
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int fd;
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QEMUFile *f;
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DPRINTF("Attempting to start an incoming migration via fd\n");
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fd = strtol(infd, NULL, 0);
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f = qemu_fdopen(fd, "rb");
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if(f == NULL) {
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DPRINTF("Unable to apply qemu wrapper to file descriptor\n");
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return -errno;
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}
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qemu_set_fd_handler2(fd, NULL, fd_accept_incoming_migration, NULL, f);
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return 0;
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}
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