src/import/export-tar.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <sys/stat.h>
   4
   5 #include "sd-daemon.h"
   6 #include "sd-event.h"
   7
   8 #include "alloc-util.h"
   9 #include "btrfs-util.h"
  10 #include "export-tar.h"
  11 #include "fd-util.h"
  12 #include "format-util.h"
  13 #include "import-common.h"
  14 #include "log.h"
  15 #include "pretty-print.h"
  16 #include "process-util.h"
  17 #include "ratelimit.h"
  18 #include "string-util.h"
  19 #include "terminal-util.h"
  20 #include "time-util.h"
  21 #include "tmpfile-util.h"
  22
  23 #define COPY_BUFFER_SIZE (16*1024)
  24
  25 typedef struct TarExport {
  26         sd_event *event;
  27
  28         TarExportFinished on_finished;
  29         void *userdata;
  30
  31         char *path;
  32         char *temp_path;
  33
  34         int output_fd;
  35         int tar_fd;
  36
  37         ImportCompress compress;
  38
  39         sd_event_source *output_event_source;
  40
  41         void *buffer;
  42         size_t buffer_size;
  43         size_t buffer_allocated;
  44
  45         uint64_t written_compressed;
  46         uint64_t written_uncompressed;
  47
  48         pid_t tar_pid;
  49
  50         struct stat st;
  51         uint64_t quota_referenced;
  52
  53         unsigned last_percent;
  54         RateLimit progress_ratelimit;
  55
  56         bool eof;
  57         bool tried_splice;
  58 } TarExport;
  59
  60 TarExport *tar_export_unref(TarExport *e) {
  61         if (!e)
  62                 return NULL;
  63
  64         sd_event_source_unref(e->output_event_source);
  65
  66         if (e->tar_pid > 1)
  67                 sigkill_wait(e->tar_pid);
  68
  69         if (e->temp_path) {
  70                 (void) btrfs_subvol_remove(e->temp_path, BTRFS_REMOVE_QUOTA);
  71                 free(e->temp_path);
  72         }
  73
  74         import_compress_free(&e->compress);
  75
  76         sd_event_unref(e->event);
  77
  78         safe_close(e->tar_fd);
  79
  80         free(e->buffer);
  81         free(e->path);
  82         return mfree(e);
  83 }
  84
  85 int tar_export_new(
  86                 TarExport **ret,
  87                 sd_event *event,
  88                 TarExportFinished on_finished,
  89                 void *userdata) {
  90
  91         _cleanup_(tar_export_unrefp) TarExport *e = NULL;
  92         int r;
  93
  94         assert(ret);
  95
  96         e = new(TarExport, 1);
  97         if (!e)
  98                 return -ENOMEM;
  99
 100         *e = (TarExport) {
 101                 .output_fd = -EBADF,
 102                 .tar_fd = -EBADF,
 103                 .on_finished = on_finished,
 104                 .userdata = userdata,
 105                 .quota_referenced = UINT64_MAX,
 106                 .last_percent = UINT_MAX,
 107                 .progress_ratelimit = { 100 * USEC_PER_MSEC, 1 },
 108         };
 109
 110         if (event)
 111                 e->event = sd_event_ref(event);
 112         else {
 113                 r = sd_event_default(&e->event);
 114                 if (r < 0)
 115                         return r;
 116         }
 117
 118         *ret = TAKE_PTR(e);
 119
 120         return 0;
 121 }
 122
 123 static void tar_export_report_progress(TarExport *e) {
 124         unsigned percent;
 125         assert(e);
 126
 127         /* Do we have any quota info? If not, we don't know anything about the progress */
 128         if (e->quota_referenced == UINT64_MAX)
 129                 return;
 130
 131         if (e->written_uncompressed >= e->quota_referenced)
 132                 percent = 100;
 133         else
 134                 percent = (unsigned) ((e->written_uncompressed * UINT64_C(100)) / e->quota_referenced);
 135
 136         if (percent == e->last_percent)
 137                 return;
 138
 139         if (!ratelimit_below(&e->progress_ratelimit))
 140                 return;
 141
 142         sd_notifyf(false, "X_IMPORT_PROGRESS=%u%%", percent);
 143
 144         if (isatty_safe(STDERR_FILENO))
 145                 (void) draw_progress_barf(
 146                                 percent,
 147                                 "%s %s/%s",
 148                                 glyph(GLYPH_ARROW_RIGHT),
 149                                 FORMAT_BYTES(e->written_uncompressed),
 150                                 FORMAT_BYTES(e->quota_referenced));
 151         else
 152                 log_info("Exported %u%%.", percent);
 153
 154         e->last_percent = percent;
 155 }
 156
 157 static int tar_export_finish(TarExport *e) {
 158         int r;
 159
 160         assert(e);
 161         assert(e->tar_fd >= 0);
 162
 163         if (e->tar_pid > 0) {
 164                 r = wait_for_terminate_and_check("tar", TAKE_PID(e->tar_pid), WAIT_LOG);
 165                 if (r < 0)
 166                         return r;
 167                 if (r != EXIT_SUCCESS)
 168                         return -EPROTO;
 169         }
 170
 171         e->tar_fd = safe_close(e->tar_fd);
 172
 173         return 0;
 174 }
 175
 176 static int tar_export_process(TarExport *e) {
 177         ssize_t l;
 178         int r;
 179
 180         assert(e);
 181
 182         if (!e->tried_splice && e->compress.type == IMPORT_COMPRESS_UNCOMPRESSED) {
 183
 184                 l = splice(e->tar_fd, NULL, e->output_fd, NULL, COPY_BUFFER_SIZE, 0);
 185                 if (l < 0) {
 186                         if (errno == EAGAIN)
 187                                 return 0;
 188
 189                         e->tried_splice = true;
 190                 } else if (l == 0) {
 191                         r = tar_export_finish(e);
 192                         goto finish;
 193                 } else {
 194                         e->written_uncompressed += l;
 195                         e->written_compressed += l;
 196
 197                         tar_export_report_progress(e);
 198
 199                         return 0;
 200                 }
 201         }
 202
 203         while (e->buffer_size <= 0) {
 204                 uint8_t input[COPY_BUFFER_SIZE];
 205
 206                 if (e->eof) {
 207                         r = tar_export_finish(e);
 208                         goto finish;
 209                 }
 210
 211                 l = read(e->tar_fd, input, sizeof(input));
 212                 if (l < 0) {
 213                         r = log_error_errno(errno, "Failed to read tar file: %m");
 214                         goto finish;
 215                 }
 216
 217                 if (l == 0) {
 218                         e->eof = true;
 219                         r = import_compress_finish(&e->compress, &e->buffer, &e->buffer_size, &e->buffer_allocated);
 220                 } else {
 221                         e->written_uncompressed += l;
 222                         r = import_compress(&e->compress, input, l, &e->buffer, &e->buffer_size, &e->buffer_allocated);
 223                 }
 224                 if (r < 0) {
 225                         r = log_error_errno(r, "Failed to encode: %m");
 226                         goto finish;
 227                 }
 228         }
 229
 230         l = write(e->output_fd, e->buffer, e->buffer_size);
 231         if (l < 0) {
 232                 if (errno == EAGAIN)
 233                         return 0;
 234
 235                 r = log_error_errno(errno, "Failed to write output file: %m");
 236                 goto finish;
 237         }
 238
 239         assert((size_t) l <= e->buffer_size);
 240         memmove(e->buffer, (uint8_t*) e->buffer + l, e->buffer_size - l);
 241         e->buffer_size -= l;
 242         e->written_compressed += l;
 243
 244         tar_export_report_progress(e);
 245
 246         return 0;
 247
 248 finish:
 249         if (r >= 0 && isatty_safe(STDERR_FILENO))
 250                 clear_progress_bar(/* prefix= */ NULL);
 251
 252         if (e->on_finished)
 253                 e->on_finished(e, r, e->userdata);
 254         else
 255                 sd_event_exit(e->event, r);
 256
 257         return 0;
 258 }
 259
 260 static int tar_export_on_output(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
 261         TarExport *i = userdata;
 262
 263         return tar_export_process(i);
 264 }
 265
 266 static int tar_export_on_defer(sd_event_source *s, void *userdata) {
 267         TarExport *i = userdata;
 268
 269         return tar_export_process(i);
 270 }
 271
 272 int tar_export_start(TarExport *e, const char *path, int fd, ImportCompressType compress) {
 273         _cleanup_close_ int sfd = -EBADF;
 274         int r;
 275
 276         assert(e);
 277         assert(path);
 278         assert(fd >= 0);
 279         assert(compress < _IMPORT_COMPRESS_TYPE_MAX);
 280         assert(compress != IMPORT_COMPRESS_UNKNOWN);
 281
 282         if (e->output_fd >= 0)
 283                 return -EBUSY;
 284
 285         sfd = open(path, O_DIRECTORY|O_RDONLY|O_NOCTTY|O_CLOEXEC);
 286         if (sfd < 0)
 287                 return -errno;
 288
 289         if (fstat(sfd, &e->st) < 0)
 290                 return -errno;
 291
 292         r = fd_nonblock(fd, true);
 293         if (r < 0)
 294                 return r;
 295
 296         r = free_and_strdup(&e->path, path);
 297         if (r < 0)
 298                 return r;
 299
 300         e->quota_referenced = UINT64_MAX;
 301
 302         if (btrfs_might_be_subvol(&e->st)) {
 303                 BtrfsQuotaInfo q;
 304
 305                 r = btrfs_subvol_get_subtree_quota_fd(sfd, 0, &q);
 306                 if (r >= 0)
 307                         e->quota_referenced = q.referenced;
 308
 309                 e->temp_path = mfree(e->temp_path);
 310
 311                 r = tempfn_random(path, NULL, &e->temp_path);
 312                 if (r < 0)
 313                         return r;
 314
 315                 /* Let's try to make a snapshot, if we can, so that the export is atomic */
 316                 r = btrfs_subvol_snapshot_at(sfd, NULL, AT_FDCWD, e->temp_path, BTRFS_SNAPSHOT_READ_ONLY|BTRFS_SNAPSHOT_RECURSIVE);
 317                 if (r < 0) {
 318                         log_debug_errno(r, "Couldn't create snapshot %s of %s, not exporting atomically: %m", e->temp_path, path);
 319                         e->temp_path = mfree(e->temp_path);
 320                 }
 321         }
 322
 323         r = import_compress_init(&e->compress, compress);
 324         if (r < 0)
 325                 return r;
 326
 327         r = sd_event_add_io(e->event, &e->output_event_source, fd, EPOLLOUT, tar_export_on_output, e);
 328         if (r == -EPERM) {
 329                 r = sd_event_add_defer(e->event, &e->output_event_source, tar_export_on_defer, e);
 330                 if (r < 0)
 331                         return r;
 332
 333                 r = sd_event_source_set_enabled(e->output_event_source, SD_EVENT_ON);
 334         }
 335         if (r < 0)
 336                 return r;
 337
 338         e->tar_fd = import_fork_tar_c(e->temp_path ?: e->path, &e->tar_pid);
 339         if (e->tar_fd < 0) {
 340                 e->output_event_source = sd_event_source_unref(e->output_event_source);
 341                 return e->tar_fd;
 342         }
 343
 344         e->output_fd = fd;
 345         return r;
 346 }