src/import/export-tar.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2015 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include "sd-daemon.h"
  21
  22 #include "alloc-util.h"
  23 #include "btrfs-util.h"
  24 #include "export-tar.h"
  25 #include "fd-util.h"
  26 #include "fileio.h"
  27 #include "import-common.h"
  28 #include "process-util.h"
  29 #include "ratelimit.h"
  30 #include "string-util.h"
  31 #include "util.h"
  32
  33 #define COPY_BUFFER_SIZE (16*1024)
  34
  35 struct TarExport {
  36         sd_event *event;
  37
  38         TarExportFinished on_finished;
  39         void *userdata;
  40
  41         char *path;
  42         char *temp_path;
  43
  44         int output_fd;
  45         int tar_fd;
  46
  47         ImportCompress compress;
  48
  49         sd_event_source *output_event_source;
  50
  51         void *buffer;
  52         size_t buffer_size;
  53         size_t buffer_allocated;
  54
  55         uint64_t written_compressed;
  56         uint64_t written_uncompressed;
  57
  58         pid_t tar_pid;
  59
  60         struct stat st;
  61         uint64_t quota_referenced;
  62
  63         unsigned last_percent;
  64         RateLimit progress_rate_limit;
  65
  66         bool eof;
  67         bool tried_splice;
  68 };
  69
  70 TarExport *tar_export_unref(TarExport *e) {
  71         if (!e)
  72                 return NULL;
  73
  74         sd_event_source_unref(e->output_event_source);
  75
  76         if (e->tar_pid > 1) {
  77                 (void) kill_and_sigcont(e->tar_pid, SIGKILL);
  78                 (void) wait_for_terminate(e->tar_pid, NULL);
  79         }
  80
  81         if (e->temp_path) {
  82                 (void) btrfs_subvol_remove(e->temp_path, BTRFS_REMOVE_QUOTA);
  83                 free(e->temp_path);
  84         }
  85
  86         import_compress_free(&e->compress);
  87
  88         sd_event_unref(e->event);
  89
  90         safe_close(e->tar_fd);
  91
  92         free(e->buffer);
  93         free(e->path);
  94         return mfree(e);
  95 }
  96
  97 int tar_export_new(
  98                 TarExport **ret,
  99                 sd_event *event,
 100                 TarExportFinished on_finished,
 101                 void *userdata) {
 102
 103         _cleanup_(tar_export_unrefp) TarExport *e = NULL;
 104         int r;
 105
 106         assert(ret);
 107
 108         e = new0(TarExport, 1);
 109         if (!e)
 110                 return -ENOMEM;
 111
 112         e->output_fd = e->tar_fd = -1;
 113         e->on_finished = on_finished;
 114         e->userdata = userdata;
 115         e->quota_referenced = (uint64_t) -1;
 116
 117         RATELIMIT_INIT(e->progress_rate_limit, 100 * USEC_PER_MSEC, 1);
 118         e->last_percent = (unsigned) -1;
 119
 120         if (event)
 121                 e->event = sd_event_ref(event);
 122         else {
 123                 r = sd_event_default(&e->event);
 124                 if (r < 0)
 125                         return r;
 126         }
 127
 128         *ret = e;
 129         e = NULL;
 130
 131         return 0;
 132 }
 133
 134 static void tar_export_report_progress(TarExport *e) {
 135         unsigned percent;
 136         assert(e);
 137
 138         /* Do we have any quota info? If not, we don't know anything about the progress */
 139         if (e->quota_referenced == (uint64_t) -1)
 140                 return;
 141
 142         if (e->written_uncompressed >= e->quota_referenced)
 143                 percent = 100;
 144         else
 145                 percent = (unsigned) ((e->written_uncompressed * UINT64_C(100)) / e->quota_referenced);
 146
 147         if (percent == e->last_percent)
 148                 return;
 149
 150         if (!ratelimit_test(&e->progress_rate_limit))
 151                 return;
 152
 153         sd_notifyf(false, "X_IMPORT_PROGRESS=%u", percent);
 154         log_info("Exported %u%%.", percent);
 155
 156         e->last_percent = percent;
 157 }
 158
 159 static int tar_export_process(TarExport *e) {
 160         ssize_t l;
 161         int r;
 162
 163         assert(e);
 164
 165         if (!e->tried_splice && e->compress.type == IMPORT_COMPRESS_UNCOMPRESSED) {
 166
 167                 l = splice(e->tar_fd, NULL, e->output_fd, NULL, COPY_BUFFER_SIZE, 0);
 168                 if (l < 0) {
 169                         if (errno == EAGAIN)
 170                                 return 0;
 171
 172                         e->tried_splice = true;
 173                 } else if (l == 0) {
 174                         r = 0;
 175                         goto finish;
 176                 } else {
 177                         e->written_uncompressed += l;
 178                         e->written_compressed += l;
 179
 180                         tar_export_report_progress(e);
 181
 182                         return 0;
 183                 }
 184         }
 185
 186         while (e->buffer_size <= 0) {
 187                 uint8_t input[COPY_BUFFER_SIZE];
 188
 189                 if (e->eof) {
 190                         r = 0;
 191                         goto finish;
 192                 }
 193
 194                 l = read(e->tar_fd, input, sizeof(input));
 195                 if (l < 0) {
 196                         r = log_error_errno(errno, "Failed to read tar file: %m");
 197                         goto finish;
 198                 }
 199
 200                 if (l == 0) {
 201                         e->eof = true;
 202                         r = import_compress_finish(&e->compress, &e->buffer, &e->buffer_size, &e->buffer_allocated);
 203                 } else {
 204                         e->written_uncompressed += l;
 205                         r = import_compress(&e->compress, input, l, &e->buffer, &e->buffer_size, &e->buffer_allocated);
 206                 }
 207                 if (r < 0) {
 208                         r = log_error_errno(r, "Failed to encode: %m");
 209                         goto finish;
 210                 }
 211         }
 212
 213         l = write(e->output_fd, e->buffer, e->buffer_size);
 214         if (l < 0) {
 215                 if (errno == EAGAIN)
 216                         return 0;
 217
 218                 r = log_error_errno(errno, "Failed to write output file: %m");
 219                 goto finish;
 220         }
 221
 222         assert((size_t) l <= e->buffer_size);
 223         memmove(e->buffer, (uint8_t*) e->buffer + l, e->buffer_size - l);
 224         e->buffer_size -= l;
 225         e->written_compressed += l;
 226
 227         tar_export_report_progress(e);
 228
 229         return 0;
 230
 231 finish:
 232         if (e->on_finished)
 233                 e->on_finished(e, r, e->userdata);
 234         else
 235                 sd_event_exit(e->event, r);
 236
 237         return 0;
 238 }
 239
 240 static int tar_export_on_output(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
 241         TarExport *i = userdata;
 242
 243         return tar_export_process(i);
 244 }
 245
 246 static int tar_export_on_defer(sd_event_source *s, void *userdata) {
 247         TarExport *i = userdata;
 248
 249         return tar_export_process(i);
 250 }
 251
 252 int tar_export_start(TarExport *e, const char *path, int fd, ImportCompressType compress) {
 253         _cleanup_close_ int sfd = -1;
 254         int r;
 255
 256         assert(e);
 257         assert(path);
 258         assert(fd >= 0);
 259         assert(compress < _IMPORT_COMPRESS_TYPE_MAX);
 260         assert(compress != IMPORT_COMPRESS_UNKNOWN);
 261
 262         if (e->output_fd >= 0)
 263                 return -EBUSY;
 264
 265         sfd = open(path, O_DIRECTORY|O_RDONLY|O_NOCTTY|O_CLOEXEC);
 266         if (sfd < 0)
 267                 return -errno;
 268
 269         if (fstat(sfd, &e->st) < 0)
 270                 return -errno;
 271
 272         r = fd_nonblock(fd, true);
 273         if (r < 0)
 274                 return r;
 275
 276         r = free_and_strdup(&e->path, path);
 277         if (r < 0)
 278                 return r;
 279
 280         e->quota_referenced = (uint64_t) -1;
 281
 282         if (e->st.st_ino == 256) { /* might be a btrfs subvolume? */
 283                 BtrfsQuotaInfo q;
 284
 285                 r = btrfs_subvol_get_subtree_quota_fd(sfd, 0, &q);
 286                 if (r >= 0)
 287                         e->quota_referenced = q.referenced;
 288
 289                 e->temp_path = mfree(e->temp_path);
 290
 291                 r = tempfn_random(path, NULL, &e->temp_path);
 292                 if (r < 0)
 293                         return r;
 294
 295                 /* Let's try to make a snapshot, if we can, so that the export is atomic */
 296                 r = btrfs_subvol_snapshot_fd(sfd, e->temp_path, BTRFS_SNAPSHOT_READ_ONLY|BTRFS_SNAPSHOT_RECURSIVE);
 297                 if (r < 0) {
 298                         log_debug_errno(r, "Couldn't create snapshot %s of %s, not exporting atomically: %m", e->temp_path, path);
 299                         e->temp_path = mfree(e->temp_path);
 300                 }
 301         }
 302
 303         r = import_compress_init(&e->compress, compress);
 304         if (r < 0)
 305                 return r;
 306
 307         r = sd_event_add_io(e->event, &e->output_event_source, fd, EPOLLOUT, tar_export_on_output, e);
 308         if (r == -EPERM) {
 309                 r = sd_event_add_defer(e->event, &e->output_event_source, tar_export_on_defer, e);
 310                 if (r < 0)
 311                         return r;
 312
 313                 r = sd_event_source_set_enabled(e->output_event_source, SD_EVENT_ON);
 314         }
 315         if (r < 0)
 316                 return r;
 317
 318         e->tar_fd = import_fork_tar_c(e->temp_path ?: e->path, &e->tar_pid);
 319         if (e->tar_fd < 0) {
 320                 e->output_event_source = sd_event_source_unref(e->output_event_source);
 321                 return e->tar_fd;
 322         }
 323
 324         e->output_fd = fd;
 325         return r;
 326 }