--- /dev/null
+/*
+ * Copyright (C) 2015 Citrix Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation; version 2.1 only. with the special
+ * exception on linking described in file LICENSE.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
+ */
+
+#include "libxl_osdeps.h" /* must come before any other headers */
+
+#include "libxl_internal.h"
+
+/*
+ * Infrastructure for writing a domain to a libxl migration v2 stream.
+ *
+ * Entry points from outside:
+ * - libxl__stream_write_start()
+ * - Start writing a stream from the start.
+ *
+ * In normal operation, there are two tasks running at once; this
+ * stream processing, and the libxl-save-helper. check_all_finished()
+ * is used to join all the tasks in both success and error cases.
+ *
+ * Nomenclature for event callbacks:
+ * - $FOO_done(): Completion callback for $FOO
+ * - write_$FOO(): Set up the datacopier to write a $FOO
+ * - $BAR_header(): A $BAR record header only
+ * - $BAR_record(): A complete $BAR record with header and content
+ *
+ * The main loop for a plain VM writes:
+ * - Stream header
+ * - Libxc record
+ * - Toolstack record
+ * - if (hvm), Qemu record
+ * - End record
+ */
+
+/* Success/error/cleanup handling. */
+static void stream_success(libxl__egc *egc,
+ libxl__stream_write_state *stream);
+static void stream_complete(libxl__egc *egc,
+ libxl__stream_write_state *stream, int rc);
+static void stream_done(libxl__egc *egc,
+ libxl__stream_write_state *stream);
+static void check_all_finished(libxl__egc *egc,
+ libxl__stream_write_state *stream, int rc);
+
+/* Event chain for a plain VM. */
+static void stream_header_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int rc, int onwrite, int errnoval);
+static void libxc_header_done(libxl__egc *egc,
+ libxl__stream_write_state *stream);
+/* libxl__xc_domain_save_done() lives here, event-order wise. */
+static void write_toolstack_record(libxl__egc *egc,
+ libxl__stream_write_state *stream);
+static void toolstack_record_done(libxl__egc *egc,
+ libxl__stream_write_state *stream);
+static void write_emulator_record(libxl__egc *egc,
+ libxl__stream_write_state *stream);
+static void emulator_read_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int rc, int onwrite, int errnoval);
+static void emulator_record_done(libxl__egc *egc,
+ libxl__stream_write_state *stream);
+static void write_end_record(libxl__egc *egc,
+ libxl__stream_write_state *stream);
+
+/*----- Helpers -----*/
+
+static void write_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int rc, int onwrite, int errnoval);
+
+/* Helper to set up reading some data from the stream. */
+static void setup_write(libxl__egc *egc,
+ libxl__stream_write_state *stream,
+ const char *what,
+ libxl__sr_rec_hdr *hdr, void *body,
+ sws_record_done_cb cb)
+{
+ static const uint8_t zero_padding[1U << REC_ALIGN_ORDER] = { 0 };
+
+ libxl__datacopier_state *dc = &stream->dc;
+ int rc;
+
+ assert(stream->record_done_callback == NULL);
+
+ dc->writewhat = what;
+ dc->used = 0;
+ dc->callback = write_done;
+ rc = libxl__datacopier_start(dc);
+
+ if (rc) {
+ stream_complete(egc, stream, rc);
+ return;
+ }
+
+ size_t padsz = ROUNDUP(hdr->length, REC_ALIGN_ORDER) - hdr->length;
+
+ /* Insert header */
+ libxl__datacopier_prefixdata(egc, dc, hdr, sizeof(*hdr));
+
+ /* Optional body */
+ if (body)
+ libxl__datacopier_prefixdata(egc, dc, body, hdr->length);
+
+ /* Any required padding */
+ if (padsz > 0)
+ libxl__datacopier_prefixdata(egc, dc,
+ zero_padding, padsz);
+ stream->record_done_callback = cb;
+}
+
+static void write_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int rc, int onwrite, int errnoval)
+{
+ libxl__stream_write_state *stream = CONTAINER_OF(dc, *stream, dc);
+ STATE_AO_GC(stream->ao);
+ sws_record_done_cb cb = stream->record_done_callback;
+
+ stream->record_done_callback = NULL;
+
+ if (onwrite || errnoval)
+ stream_complete(egc, stream, rc ?: ERROR_FAIL);
+ else
+ cb(egc, stream);
+}
+
+/*----- Entrypoints -----*/
+
+void libxl__stream_write_init(libxl__stream_write_state *stream)
+{
+ stream->rc = 0;
+ stream->running = false;
+ FILLZERO(stream->dc);
+ stream->record_done_callback = NULL;
+ FILLZERO(stream->emu_dc);
+ stream->emu_carefd = NULL;
+ FILLZERO(stream->emu_rec_hdr);
+ stream->emu_body = NULL;
+}
+
+void libxl__stream_write_start(libxl__egc *egc,
+ libxl__stream_write_state *stream)
+{
+ libxl__datacopier_state *dc = &stream->dc;
+ STATE_AO_GC(stream->ao);
+ struct libxl__sr_hdr hdr;
+ int rc = 0;
+
+ libxl__stream_write_init(stream);
+
+ stream->running = true;
+
+ dc->ao = ao;
+ dc->readfd = -1;
+ dc->writewhat = "save/migration stream";
+ dc->writefd = stream->fd;
+ dc->maxsz = -1;
+ dc->callback = stream_header_done;
+
+ rc = libxl__datacopier_start(dc);
+ if (rc)
+ goto err;
+
+ FILLZERO(hdr);
+ hdr.ident = htobe64(RESTORE_STREAM_IDENT);
+ hdr.version = htobe32(RESTORE_STREAM_VERSION);
+ hdr.options = htobe32(0);
+
+ libxl__datacopier_prefixdata(egc, dc, &hdr, sizeof(hdr));
+ return;
+
+ err:
+ assert(rc);
+ stream_complete(egc, stream, rc);
+}
+
+void libxl__stream_write_abort(libxl__egc *egc,
+ libxl__stream_write_state *stream, int rc)
+{
+ assert(rc);
+
+ if (stream->running)
+ stream_complete(egc, stream, rc);
+}
+
+/*----- Event logic -----*/
+
+static void stream_header_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int rc, int onwrite, int errnoval)
+{
+ libxl__stream_write_state *stream = CONTAINER_OF(dc, *stream, dc);
+ STATE_AO_GC(stream->ao);
+ struct libxl__sr_rec_hdr rec;
+
+ if (rc || errnoval) {
+ stream_complete(egc, stream, rc ?: ERROR_FAIL);
+ return;
+ }
+
+ FILLZERO(rec);
+ rec.type = REC_TYPE_LIBXC_CONTEXT;
+
+ setup_write(egc, stream, "libxc header",
+ &rec, NULL, libxc_header_done);
+}
+
+static void libxc_header_done(libxl__egc *egc,
+ libxl__stream_write_state *stream)
+{
+ libxl__xc_domain_save(egc, stream->dss, &stream->dss->shs);
+}
+
+static void __attribute__((unused))
+write_toolstack_record(libxl__egc *egc,
+ libxl__stream_write_state *stream)
+{
+ libxl__domain_suspend_state *dss = stream->dss;
+ STATE_AO_GC(stream->ao);
+ struct libxl__sr_rec_hdr rec;
+ int rc;
+ uint8_t *toolstack_buf = NULL; /* We must free this. */
+ uint32_t toolstack_len;
+
+ rc = libxl__toolstack_save(dss->domid, &toolstack_buf,
+ &toolstack_len, dss);
+ if (rc)
+ goto err;
+
+ FILLZERO(rec);
+ rec.type = REC_TYPE_XENSTORE_DATA;
+ rec.length = toolstack_len;
+
+ setup_write(egc, stream, "toolstack record",
+ &rec, toolstack_buf,
+ toolstack_record_done);
+
+ free(toolstack_buf);
+ return;
+
+ err:
+ assert(rc);
+ free(toolstack_buf);
+ stream_complete(egc, stream, rc);
+}
+
+static void toolstack_record_done(libxl__egc *egc,
+ libxl__stream_write_state *stream)
+{
+ libxl__domain_suspend_state *dss = stream->dss;
+
+ if (dss->type == LIBXL_DOMAIN_TYPE_HVM)
+ write_emulator_record(egc, stream);
+ else
+ write_end_record(egc, stream);
+}
+
+static void write_emulator_record(libxl__egc *egc,
+ libxl__stream_write_state *stream)
+{
+ libxl__domain_suspend_state *dss = stream->dss;
+ libxl__datacopier_state *dc = &stream->emu_dc;
+ STATE_AO_GC(stream->ao);
+ struct libxl__sr_rec_hdr *rec = &stream->emu_rec_hdr;
+ struct libxl__sr_emulator_hdr *ehdr = NULL;
+ struct stat st;
+ int rc;
+
+ assert(dss->type == LIBXL_DOMAIN_TYPE_HVM);
+
+ /* Convenience aliases */
+ const char *const filename = dss->dm_savefile;
+ const uint32_t domid = dss->domid;
+
+ libxl__carefd_begin();
+ int readfd = open(filename, O_RDONLY);
+ stream->emu_carefd = libxl__carefd_opened(CTX, readfd);
+ if (readfd == -1) {
+ rc = ERROR_FAIL;
+ LOGE(ERROR, "unable to open %s", filename);
+ goto err;
+ }
+
+ if (fstat(readfd, &st)) {
+ rc = ERROR_FAIL;
+ LOGE(ERROR, "unable to fstat %s", filename);
+ goto err;
+ }
+
+ if (!S_ISREG(st.st_mode)) {
+ rc = ERROR_FAIL;
+ LOG(ERROR, "%s is not a plain file!", filename);
+ goto err;
+ }
+
+ rec->type = REC_TYPE_EMULATOR_CONTEXT;
+ rec->length = st.st_size + sizeof(*ehdr);
+ stream->emu_body = ehdr = libxl__malloc(NOGC, rec->length);
+
+ switch(libxl__device_model_version_running(gc, domid)) {
+ case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN_TRADITIONAL:
+ ehdr->id = EMULATOR_QEMU_TRADITIONAL;
+ break;
+
+ case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN:
+ ehdr->id = EMULATOR_QEMU_UPSTREAM;
+ break;
+
+ default:
+ rc = ERROR_FAIL;
+ goto err;
+ }
+ ehdr->index = 0;
+
+ FILLZERO(*dc);
+ dc->ao = stream->ao;
+ dc->readwhat = "qemu save file";
+ dc->readfd = readfd;
+ dc->maxsz = -1;
+ dc->readbuf = stream->emu_body + sizeof(*ehdr);
+ dc->bytes_to_read = rec->length - sizeof(*ehdr);
+ dc->callback = emulator_read_done;
+
+ rc = libxl__datacopier_start(dc);
+ if (rc)
+ goto err;
+
+ return;
+
+ err:
+ assert(rc);
+ stream_complete(egc, stream, rc);
+}
+
+static void emulator_read_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int rc, int onwrite, int errnoval)
+{
+ libxl__stream_write_state *stream = CONTAINER_OF(dc, *stream, emu_dc);
+ STATE_AO_GC(stream->ao);
+
+ if (rc || onwrite || errnoval) {
+ stream_complete(egc, stream, rc ?: ERROR_FAIL);
+ return;
+ }
+
+ libxl__carefd_close(stream->emu_carefd);
+ stream->emu_carefd = NULL;
+
+ setup_write(egc, stream, "emulator record",
+ &stream->emu_rec_hdr, stream->emu_body,
+ emulator_record_done);
+}
+
+static void emulator_record_done(libxl__egc *egc,
+ libxl__stream_write_state *stream)
+{
+ free(stream->emu_body);
+ stream->emu_body = NULL;
+
+ write_end_record(egc, stream);
+}
+
+static void write_end_record(libxl__egc *egc,
+ libxl__stream_write_state *stream)
+{
+ struct libxl__sr_rec_hdr rec;
+
+ FILLZERO(rec);
+ rec.type = REC_TYPE_END;
+
+ setup_write(egc, stream, "end record",
+ &rec, NULL, stream_success);
+}
+
+/*----- Success/error/cleanup handling. -----*/
+
+static void stream_success(libxl__egc *egc, libxl__stream_write_state *stream)
+{
+ stream_complete(egc, stream, 0);
+}
+
+static void stream_complete(libxl__egc *egc,
+ libxl__stream_write_state *stream, int rc)
+{
+ assert(stream->running);
+
+ if (!stream->rc)
+ stream->rc = rc;
+ stream_done(egc, stream);
+}
+
+static void stream_done(libxl__egc *egc,
+ libxl__stream_write_state *stream)
+{
+ assert(stream->running);
+ stream->running = false;
+
+ if (stream->emu_carefd)
+ libxl__carefd_close(stream->emu_carefd);
+ free(stream->emu_body);
+
+ check_all_finished(egc, stream, stream->rc);
+}
+
+static void check_all_finished(libxl__egc *egc,
+ libxl__stream_write_state *stream,
+ int rc)
+{
+ libxl__domain_suspend_state *dss = stream->dss;
+ STATE_AO_GC(stream->ao);
+
+ if (!stream->rc && rc) {
+ /* First reported failure. Tear everything down. */
+ stream->rc = rc;
+
+ libxl__stream_write_abort(egc, stream, rc);
+ libxl__save_helper_abort(egc, &dss->shs);
+ }
+
+ /* Don't fire the callback until all our parallel tasks have stopped. */
+ if (libxl__stream_write_inuse(stream) ||
+ libxl__save_helper_inuse(&dss->shs))
+ return;
+
+ stream->completion_callback(egc, stream, stream->rc);
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
projects / xen.git / commitdiff