src/import/export-tar.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include "sd-daemon.h"
   4
   5 #include "alloc-util.h"
   6 #include "btrfs-util.h"
   7 #include "export-tar.h"
   8 #include "fd-util.h"
   9 #include "import-common.h"
  10 #include "process-util.h"
  11 #include "ratelimit.h"
  12 #include "string-util.h"
  13 #include "tmpfile-util.h"
  14
  15 #define COPY_BUFFER_SIZE (16*1024)
  16
  17 struct TarExport {
  18         sd_event *event;
  19
  20         TarExportFinished on_finished;
  21         void *userdata;
  22
  23         char *path;
  24         char *temp_path;
  25
  26         int output_fd;
  27         int tar_fd;
  28
  29         ImportCompress compress;
  30
  31         sd_event_source *output_event_source;
  32
  33         void *buffer;
  34         size_t buffer_size;
  35         size_t buffer_allocated;
  36
  37         uint64_t written_compressed;
  38         uint64_t written_uncompressed;
  39
  40         pid_t tar_pid;
  41
  42         struct stat st;
  43         uint64_t quota_referenced;
  44
  45         unsigned last_percent;
  46         RateLimit progress_ratelimit;
  47
  48         bool eof;
  49         bool tried_splice;
  50 };
  51
  52 TarExport *tar_export_unref(TarExport *e) {
  53         if (!e)
  54                 return NULL;
  55
  56         sd_event_source_unref(e->output_event_source);
  57
  58         if (e->tar_pid > 1)
  59                 sigkill_wait(e->tar_pid);
  60
  61         if (e->temp_path) {
  62                 (void) btrfs_subvol_remove(e->temp_path, BTRFS_REMOVE_QUOTA);
  63                 free(e->temp_path);
  64         }
  65
  66         import_compress_free(&e->compress);
  67
  68         sd_event_unref(e->event);
  69
  70         safe_close(e->tar_fd);
  71
  72         free(e->buffer);
  73         free(e->path);
  74         return mfree(e);
  75 }
  76
  77 int tar_export_new(
  78                 TarExport **ret,
  79                 sd_event *event,
  80                 TarExportFinished on_finished,
  81                 void *userdata) {
  82
  83         _cleanup_(tar_export_unrefp) TarExport *e = NULL;
  84         int r;
  85
  86         assert(ret);
  87
  88         e = new(TarExport, 1);
  89         if (!e)
  90                 return -ENOMEM;
  91
  92         *e = (TarExport) {
  93                 .output_fd = -EBADF,
  94                 .tar_fd = -EBADF,
  95                 .on_finished = on_finished,
  96                 .userdata = userdata,
  97                 .quota_referenced = UINT64_MAX,
  98                 .last_percent = UINT_MAX,
  99                 .progress_ratelimit = { 100 * USEC_PER_MSEC, 1 },
 100         };
 101
 102         if (event)
 103                 e->event = sd_event_ref(event);
 104         else {
 105                 r = sd_event_default(&e->event);
 106                 if (r < 0)
 107                         return r;
 108         }
 109
 110         *ret = TAKE_PTR(e);
 111
 112         return 0;
 113 }
 114
 115 static void tar_export_report_progress(TarExport *e) {
 116         unsigned percent;
 117         assert(e);
 118
 119         /* Do we have any quota info? If not, we don't know anything about the progress */
 120         if (e->quota_referenced == UINT64_MAX)
 121                 return;
 122
 123         if (e->written_uncompressed >= e->quota_referenced)
 124                 percent = 100;
 125         else
 126                 percent = (unsigned) ((e->written_uncompressed * UINT64_C(100)) / e->quota_referenced);
 127
 128         if (percent == e->last_percent)
 129                 return;
 130
 131         if (!ratelimit_below(&e->progress_ratelimit))
 132                 return;
 133
 134         sd_notifyf(false, "X_IMPORT_PROGRESS=%u", percent);
 135         log_info("Exported %u%%.", percent);
 136
 137         e->last_percent = percent;
 138 }
 139
 140 static int tar_export_finish(TarExport *e) {
 141         int r;
 142
 143         assert(e);
 144         assert(e->tar_fd >= 0);
 145
 146         if (e->tar_pid > 0) {
 147                 r = wait_for_terminate_and_check("tar", TAKE_PID(e->tar_pid), WAIT_LOG);
 148                 if (r < 0)
 149                         return r;
 150                 if (r != EXIT_SUCCESS)
 151                         return -EPROTO;
 152         }
 153
 154         e->tar_fd = safe_close(e->tar_fd);
 155
 156         return 0;
 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 = tar_export_finish(e);
 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 = tar_export_finish(e);
 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 = -EBADF;
 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_MAX;
 281
 282         if (btrfs_might_be_subvol(&e->st)) {
 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 }