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Systemd/src/import/export-raw.c
Lennart Poettering 14bcf25c8b util: when creating temporary file names, allow including extra id string in it 
This adds a "char *extra" parameter to tempfn_xxxxxx(), tempfn_random(),
tempfn_ranomd_child(). If non-NULL this string is included in the middle
of the newly created file name. This is useful for being able to
distuingish the kind of temporary file when we see one.

This also adds tests for the three call.

For now, we don't make use of this at all, but port all users over.
2015-06-15 19:28:55 +02:00

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9.1 KiB
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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2015 Lennart Poettering
systemd 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; either version 2.1 of the License, or
(at your option) any later version.
systemd 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.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <sys/sendfile.h>
#include <libgen.h>
#undef basename
#include "sd-daemon.h"
#include "util.h"
#include "ratelimit.h"
#include "btrfs-util.h"
#include "copy.h"
#include "import-common.h"
#include "export-raw.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);
free(e);
return NULL;
}
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 = new0(RawExport, 1);
if (!e)
return -ENOMEM;
e->output_fd = e->input_fd = -1;
e->on_finished = on_finished;
e->userdata = userdata;
RATELIMIT_INIT(e->progress_rate_limit, 100 * USEC_PER_MSEC, 1);
e->last_percent = (unsigned) -1;
if (event)
e->event = sd_event_ref(event);
else {
r = sd_event_default(&e->event);
if (r < 0)
return r;
}
*ret = e;
e = NULL;
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_test(&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) {
char *p, *d;
int new_fd, r;
p = strdupa(path);
d = dirname(p);
new_fd = open(d, O_TMPFILE|O_CLOEXEC|O_NOCTTY|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;
if (!S_ISREG(e->st.st_mode))
return -ENOTTY;
/* 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 = tfd;
tfd = -1;
} else {
e->input_fd = sfd;
sfd = -1;
}
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;
}
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