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         free(e);
  95
  96         return NULL;
  97 }
  98
  99 int tar_export_new(
 100                 TarExport **ret,
 101                 sd_event *event,
 102                 TarExportFinished on_finished,
 103                 void *userdata) {
 104
 105         _cleanup_(tar_export_unrefp) TarExport *e = NULL;
 106         int r;
 107
 108         assert(ret);
 109
 110         e = new0(TarExport, 1);
 111         if (!e)
 112                 return -ENOMEM;
 113
 114         e->output_fd = e->tar_fd = -1;
 115         e->on_finished = on_finished;
 116         e->userdata = userdata;
 117         e->quota_referenced = (uint64_t) -1;
 118
 119         RATELIMIT_INIT(e->progress_rate_limit, 100 * USEC_PER_MSEC, 1);
 120         e->last_percent = (unsigned) -1;
 121
 122         if (event)
 123                 e->event = sd_event_ref(event);
 124         else {
 125                 r = sd_event_default(&e->event);
 126                 if (r < 0)
 127                         return r;
 128         }
 129
 130         *ret = e;
 131         e = NULL;
 132
 133         return 0;
 134 }
 135
 136 static void tar_export_report_progress(TarExport *e) {
 137         unsigned percent;
 138         assert(e);
 139
 140         /* Do we have any quota info? If not, we don't know anything about the progress */
 141         if (e->quota_referenced == (uint64_t) -1)
 142                 return;
 143
 144         if (e->written_uncompressed >= e->quota_referenced)
 145                 percent = 100;
 146         else
 147                 percent = (unsigned) ((e->written_uncompressed * UINT64_C(100)) / e->quota_referenced);
 148
 149         if (percent == e->last_percent)
 150                 return;
 151
 152         if (!ratelimit_test(&e->progress_rate_limit))
 153                 return;
 154
 155         sd_notifyf(false, "X_IMPORT_PROGRESS=%u", percent);
 156         log_info("Exported %u%%.", percent);
 157
 158         e->last_percent = percent;
 159 }
 160
 161 static int tar_export_process(TarExport *e) {
 162         ssize_t l;
 163         int r;
 164
 165         assert(e);
 166
 167         if (!e->tried_splice && e->compress.type == IMPORT_COMPRESS_UNCOMPRESSED) {
 168
 169                 l = splice(e->tar_fd, NULL, e->output_fd, NULL, COPY_BUFFER_SIZE, 0);
 170                 if (l < 0) {
 171                         if (errno == EAGAIN)
 172                                 return 0;
 173
 174                         e->tried_splice = true;
 175                 } else if (l == 0) {
 176                         r = 0;
 177                         goto finish;
 178                 } else {
 179                         e->written_uncompressed += l;
 180                         e->written_compressed += l;
 181
 182                         tar_export_report_progress(e);
 183
 184                         return 0;
 185                 }
 186         }
 187
 188         while (e->buffer_size <= 0) {
 189                 uint8_t input[COPY_BUFFER_SIZE];
 190
 191                 if (e->eof) {
 192                         r = 0;
 193                         goto finish;
 194                 }
 195
 196                 l = read(e->tar_fd, input, sizeof(input));
 197                 if (l < 0) {
 198                         r = log_error_errno(errno, "Failed to read tar file: %m");
 199                         goto finish;
 200                 }
 201
 202                 if (l == 0) {
 203                         e->eof = true;
 204                         r = import_compress_finish(&e->compress, &e->buffer, &e->buffer_size, &e->buffer_allocated);
 205                 } else {
 206                         e->written_uncompressed += l;
 207                         r = import_compress(&e->compress, input, l, &e->buffer, &e->buffer_size, &e->buffer_allocated);
 208                 }
 209                 if (r < 0) {
 210                         r = log_error_errno(r, "Failed to encode: %m");
 211                         goto finish;
 212                 }
 213         }
 214
 215         l = write(e->output_fd, e->buffer, e->buffer_size);
 216         if (l < 0) {
 217                 if (errno == EAGAIN)
 218                         return 0;
 219
 220                 r = log_error_errno(errno, "Failed to write output file: %m");
 221                 goto finish;
 222         }
 223
 224         assert((size_t) l <= e->buffer_size);
 225         memmove(e->buffer, (uint8_t*) e->buffer + l, e->buffer_size - l);
 226         e->buffer_size -= l;
 227         e->written_compressed += l;
 228
 229         tar_export_report_progress(e);
 230
 231         return 0;
 232
 233 finish:
 234         if (e->on_finished)
 235                 e->on_finished(e, r, e->userdata);
 236         else
 237                 sd_event_exit(e->event, r);
 238
 239         return 0;
 240 }
 241
 242 static int tar_export_on_output(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
 243         TarExport *i = userdata;
 244
 245         return tar_export_process(i);
 246 }
 247
 248 static int tar_export_on_defer(sd_event_source *s, void *userdata) {
 249         TarExport *i = userdata;
 250
 251         return tar_export_process(i);
 252 }
 253
 254 int tar_export_start(TarExport *e, const char *path, int fd, ImportCompressType compress) {
 255         _cleanup_close_ int sfd = -1;
 256         int r;
 257
 258         assert(e);
 259         assert(path);
 260         assert(fd >= 0);
 261         assert(compress < _IMPORT_COMPRESS_TYPE_MAX);
 262         assert(compress != IMPORT_COMPRESS_UNKNOWN);
 263
 264         if (e->output_fd >= 0)
 265                 return -EBUSY;
 266
 267         sfd = open(path, O_DIRECTORY|O_RDONLY|O_NOCTTY|O_CLOEXEC);
 268         if (sfd < 0)
 269                 return -errno;
 270
 271         if (fstat(sfd, &e->st) < 0)
 272                 return -errno;
 273
 274         r = fd_nonblock(fd, true);
 275         if (r < 0)
 276                 return r;
 277
 278         r = free_and_strdup(&e->path, path);
 279         if (r < 0)
 280                 return r;
 281
 282         e->quota_referenced = (uint64_t) -1;
 283
 284         if (e->st.st_ino == 256) { /* might be a btrfs subvolume? */
 285                 BtrfsQuotaInfo q;
 286
 287                 r = btrfs_subvol_get_subtree_quota_fd(sfd, 0, &q);
 288                 if (r >= 0)
 289                         e->quota_referenced = q.referenced;
 290
 291                 e->temp_path = mfree(e->temp_path);
 292
 293                 r = tempfn_random(path, NULL, &e->temp_path);
 294                 if (r < 0)
 295                         return r;
 296
 297                 /* Let's try to make a snapshot, if we can, so that the export is atomic */
 298                 r = btrfs_subvol_snapshot_fd(sfd, e->temp_path, BTRFS_SNAPSHOT_READ_ONLY|BTRFS_SNAPSHOT_RECURSIVE);
 299                 if (r < 0) {
 300                         log_debug_errno(r, "Couldn't create snapshot %s of %s, not exporting atomically: %m", e->temp_path, path);
 301                         e->temp_path = mfree(e->temp_path);
 302                 }
 303         }
 304
 305         r = import_compress_init(&e->compress, compress);
 306         if (r < 0)
 307                 return r;
 308
 309         r = sd_event_add_io(e->event, &e->output_event_source, fd, EPOLLOUT, tar_export_on_output, e);
 310         if (r == -EPERM) {
 311                 r = sd_event_add_defer(e->event, &e->output_event_source, tar_export_on_defer, e);
 312                 if (r < 0)
 313                         return r;
 314
 315                 r = sd_event_source_set_enabled(e->output_event_source, SD_EVENT_ON);
 316         }
 317         if (r < 0)
 318                 return r;
 319
 320         e->tar_fd = import_fork_tar_c(e->temp_path ?: e->path, &e->tar_pid);
 321         if (e->tar_fd < 0) {
 322                 e->output_event_source = sd_event_source_unref(e->output_event_source);
 323                 return e->tar_fd;
 324         }
 325
 326         e->output_fd = fd;
 327         return r;
 328 }