1 files changed, 332 insertions, 0 deletions

diff --git a/src/import/export-raw.c b/src/import/export-raw.c
new file mode 100644
index 0000000..6a02b47
--- /dev/null
+++ b/src/import/export-raw.c
@@ -0,0 +1,332 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <sys/sendfile.h>
+
+/* When we include libgen.h because we need dirname() we immediately
+ * undefine basename() since libgen.h defines it as a macro to the POSIX
+ * version which is really broken. We prefer GNU basename(). */
+#include <libgen.h>
+#undef basename
+
+#include "sd-daemon.h"
+
+#include "alloc-util.h"
+#include "btrfs-util.h"
+#include "copy.h"
+#include "export-raw.h"
+#include "fd-util.h"
+#include "fs-util.h"
+#include "import-common.h"
+#include "missing.h"
+#include "ratelimit.h"
+#include "stat-util.h"
+#include "string-util.h"
+#include "tmpfile-util.h"
+#include "util.h"
+
+#define COPY_BUFFER_SIZE (16*1024)
+
+struct RawExport {
+        sd_event *event;
+
+        RawExportFinished on_finished;
+        void *userdata;
+
+        char *path;
+
+        int input_fd;
+        int output_fd;
+
+        ImportCompress compress;
+
+        sd_event_source *output_event_source;
+
+        void *buffer;
+        size_t buffer_size;
+        size_t buffer_allocated;
+
+        uint64_t written_compressed;
+        uint64_t written_uncompressed;
+
+        unsigned last_percent;
+        RateLimit progress_rate_limit;
+
+        struct stat st;
+
+        bool eof;
+        bool tried_reflink;
+        bool tried_sendfile;
+};
+
+RawExport *raw_export_unref(RawExport *e) {
+        if (!e)
+                return NULL;
+
+        sd_event_source_unref(e->output_event_source);
+
+        import_compress_free(&e->compress);
+
+        sd_event_unref(e->event);
+
+        safe_close(e->input_fd);
+
+        free(e->buffer);
+        free(e->path);
+        return mfree(e);
+}
+
+int raw_export_new(
+                RawExport **ret,
+                sd_event *event,
+                RawExportFinished on_finished,
+                void *userdata) {
+
+        _cleanup_(raw_export_unrefp) RawExport *e = NULL;
+        int r;
+
+        assert(ret);
+
+        e = new(RawExport, 1);
+        if (!e)
+                return -ENOMEM;
+
+        *e = (RawExport) {
+                .output_fd = -1,
+                .input_fd = -1,
+                .on_finished = on_finished,
+                .userdata = userdata,
+                .last_percent = (unsigned) -1,
+        };
+
+        RATELIMIT_INIT(e->progress_rate_limit, 100 * USEC_PER_MSEC, 1);
+
+        if (event)
+                e->event = sd_event_ref(event);
+        else {
+                r = sd_event_default(&e->event);
+                if (r < 0)
+                        return r;
+        }
+
+        *ret = TAKE_PTR(e);
+
+        return 0;
+}
+
+static void raw_export_report_progress(RawExport *e) {
+        unsigned percent;
+        assert(e);
+
+        if (e->written_uncompressed >= (uint64_t) e->st.st_size)
+                percent = 100;
+        else
+                percent = (unsigned) ((e->written_uncompressed * UINT64_C(100)) / (uint64_t) e->st.st_size);
+
+        if (percent == e->last_percent)
+                return;
+
+        if (!ratelimit_below(&e->progress_rate_limit))
+                return;
+
+        sd_notifyf(false, "X_IMPORT_PROGRESS=%u", percent);
+        log_info("Exported %u%%.", percent);
+
+        e->last_percent = percent;
+}
+
+static int raw_export_process(RawExport *e) {
+        ssize_t l;
+        int r;
+
+        assert(e);
+
+        if (!e->tried_reflink && e->compress.type == IMPORT_COMPRESS_UNCOMPRESSED) {
+
+                /* If we shall take an uncompressed snapshot we can
+                 * reflink source to destination directly. Let's see
+                 * if this works. */
+
+                r = btrfs_reflink(e->input_fd, e->output_fd);
+                if (r >= 0) {
+                        r = 0;
+                        goto finish;
+                }
+
+                e->tried_reflink = true;
+        }
+
+        if (!e->tried_sendfile && e->compress.type == IMPORT_COMPRESS_UNCOMPRESSED) {
+
+                l = sendfile(e->output_fd, e->input_fd, NULL, COPY_BUFFER_SIZE);
+                if (l < 0) {
+                        if (errno == EAGAIN)
+                                return 0;
+
+                        e->tried_sendfile = true;
+                } else if (l == 0) {
+                        r = 0;
+                        goto finish;
+                } else {
+                        e->written_uncompressed += l;
+                        e->written_compressed += l;
+
+                        raw_export_report_progress(e);
+
+                        return 0;
+                }
+        }
+
+        while (e->buffer_size <= 0) {
+                uint8_t input[COPY_BUFFER_SIZE];
+
+                if (e->eof) {
+                        r = 0;
+                        goto finish;
+                }
+
+                l = read(e->input_fd, input, sizeof(input));
+                if (l < 0) {
+                        r = log_error_errno(errno, "Failed to read raw file: %m");
+                        goto finish;
+                }
+
+                if (l == 0) {
+                        e->eof = true;
+                        r = import_compress_finish(&e->compress, &e->buffer, &e->buffer_size, &e->buffer_allocated);
+                } else {
+                        e->written_uncompressed += l;
+                        r = import_compress(&e->compress, input, l, &e->buffer, &e->buffer_size, &e->buffer_allocated);
+                }
+                if (r < 0) {
+                        r = log_error_errno(r, "Failed to encode: %m");
+                        goto finish;
+                }
+        }
+
+        l = write(e->output_fd, e->buffer, e->buffer_size);
+        if (l < 0) {
+                if (errno == EAGAIN)
+                        return 0;
+
+                r = log_error_errno(errno, "Failed to write output file: %m");
+                goto finish;
+        }
+
+        assert((size_t) l <= e->buffer_size);
+        memmove(e->buffer, (uint8_t*) e->buffer + l, e->buffer_size - l);
+        e->buffer_size -= l;
+        e->written_compressed += l;
+
+        raw_export_report_progress(e);
+
+        return 0;
+
+finish:
+        if (r >= 0) {
+                (void) copy_times(e->input_fd, e->output_fd);
+                (void) copy_xattr(e->input_fd, e->output_fd);
+        }
+
+        if (e->on_finished)
+                e->on_finished(e, r, e->userdata);
+        else
+                sd_event_exit(e->event, r);
+
+        return 0;
+}
+
+static int raw_export_on_output(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+        RawExport *i = userdata;
+
+        return raw_export_process(i);
+}
+
+static int raw_export_on_defer(sd_event_source *s, void *userdata) {
+        RawExport *i = userdata;
+
+        return raw_export_process(i);
+}
+
+static int reflink_snapshot(int fd, const char *path) {
+        int new_fd, r;
+
+        new_fd = open_parent(path, O_TMPFILE|O_CLOEXEC|O_RDWR, 0600);
+        if (new_fd < 0) {
+                _cleanup_free_ char *t = NULL;
+
+                r = tempfn_random(path, NULL, &t);
+                if (r < 0)
+                        return r;
+
+                new_fd = open(t, O_CLOEXEC|O_CREAT|O_NOCTTY|O_RDWR, 0600);
+                if (new_fd < 0)
+                        return -errno;
+
+                (void) unlink(t);
+        }
+
+        r = btrfs_reflink(fd, new_fd);
+        if (r < 0) {
+                safe_close(new_fd);
+                return r;
+        }
+
+        return new_fd;
+}
+
+int raw_export_start(RawExport *e, const char *path, int fd, ImportCompressType compress) {
+        _cleanup_close_ int sfd = -1, tfd = -1;
+        int r;
+
+        assert(e);
+        assert(path);
+        assert(fd >= 0);
+        assert(compress < _IMPORT_COMPRESS_TYPE_MAX);
+        assert(compress != IMPORT_COMPRESS_UNKNOWN);
+
+        if (e->output_fd >= 0)
+                return -EBUSY;
+
+        r = fd_nonblock(fd, true);
+        if (r < 0)
+                return r;
+
+        r = free_and_strdup(&e->path, path);
+        if (r < 0)
+                return r;
+
+        sfd = open(path, O_RDONLY|O_CLOEXEC|O_NOCTTY);
+        if (sfd < 0)
+                return -errno;
+
+        if (fstat(sfd, &e->st) < 0)
+                return -errno;
+        r = stat_verify_regular(&e->st);
+        if (r < 0)
+                return r;
+
+        /* Try to take a reflink snapshot of the file, if we can t make the export atomic */
+        tfd = reflink_snapshot(sfd, path);
+        if (tfd >= 0)
+                e->input_fd = TAKE_FD(tfd);
+        else
+                e->input_fd = TAKE_FD(sfd);
+
+        r = import_compress_init(&e->compress, compress);
+        if (r < 0)
+                return r;
+
+        r = sd_event_add_io(e->event, &e->output_event_source, fd, EPOLLOUT, raw_export_on_output, e);
+        if (r == -EPERM) {
+                r = sd_event_add_defer(e->event, &e->output_event_source, raw_export_on_defer, e);
+                if (r < 0)
+                        return r;
+
+                r = sd_event_source_set_enabled(e->output_event_source, SD_EVENT_ON);
+        }
+        if (r < 0)
+                return r;
+
+        e->output_fd = fd;
+        return r;
+}