src/import/export-tar.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   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 "fileio.h"
  10 #include "import-common.h"
  11 #include "process-util.h"
  12 #include "ratelimit.h"
  13 #include "string-util.h"
  14 #include "util.h"
  15
  16 #define COPY_BUFFER_SIZE (16*1024)
  17
  18 struct TarExport {
  19         sd_event *event;
  20
  21         TarExportFinished on_finished;
  22         void *userdata;
  23
  24         char *path;
  25         char *temp_path;
  26
  27         int output_fd;
  28         int tar_fd;
  29
  30         ImportCompress compress;
  31
  32         sd_event_source *output_event_source;
  33
  34         void *buffer;
  35         size_t buffer_size;
  36         size_t buffer_allocated;
  37
  38         uint64_t written_compressed;
  39         uint64_t written_uncompressed;
  40
  41         pid_t tar_pid;
  42
  43         struct stat st;
  44         uint64_t quota_referenced;
  45
  46         unsigned last_percent;
  47         RateLimit progress_rate_limit;
  48
  49         bool eof;
  50         bool tried_splice;
  51 };
  52
  53 TarExport *tar_export_unref(TarExport *e) {
  54         if (!e)
  55                 return NULL;
  56
  57         sd_event_source_unref(e->output_event_source);
  58
  59         if (e->tar_pid > 1) {
  60                 (void) kill_and_sigcont(e->tar_pid, SIGKILL);
  61                 (void) wait_for_terminate(e->tar_pid, NULL);
  62         }
  63
  64         if (e->temp_path) {
  65                 (void) btrfs_subvol_remove(e->temp_path, BTRFS_REMOVE_QUOTA);
  66                 free(e->temp_path);
  67         }
  68
  69         import_compress_free(&e->compress);
  70
  71         sd_event_unref(e->event);
  72
  73         safe_close(e->tar_fd);
  74
  75         free(e->buffer);
  76         free(e->path);
  77         return mfree(e);
  78 }
  79
  80 int tar_export_new(
  81                 TarExport **ret,
  82                 sd_event *event,
  83                 TarExportFinished on_finished,
  84                 void *userdata) {
  85
  86         _cleanup_(tar_export_unrefp) TarExport *e = NULL;
  87         int r;
  88
  89         assert(ret);
  90
  91         e = new0(TarExport, 1);
  92         if (!e)
  93                 return -ENOMEM;
  94
  95         e->output_fd = e->tar_fd = -1;
  96         e->on_finished = on_finished;
  97         e->userdata = userdata;
  98         e->quota_referenced = (uint64_t) -1;
  99
 100         RATELIMIT_INIT(e->progress_rate_limit, 100 * USEC_PER_MSEC, 1);
 101         e->last_percent = (unsigned) -1;
 102
 103         if (event)
 104                 e->event = sd_event_ref(event);
 105         else {
 106                 r = sd_event_default(&e->event);
 107                 if (r < 0)
 108                         return r;
 109         }
 110
 111         *ret = TAKE_PTR(e);
 112
 113         return 0;
 114 }
 115
 116 static void tar_export_report_progress(TarExport *e) {
 117         unsigned percent;
 118         assert(e);
 119
 120         /* Do we have any quota info? If not, we don't know anything about the progress */
 121         if (e->quota_referenced == (uint64_t) -1)
 122                 return;
 123
 124         if (e->written_uncompressed >= e->quota_referenced)
 125                 percent = 100;
 126         else
 127                 percent = (unsigned) ((e->written_uncompressed * UINT64_C(100)) / e->quota_referenced);
 128
 129         if (percent == e->last_percent)
 130                 return;
 131
 132         if (!ratelimit_below(&e->progress_rate_limit))
 133                 return;
 134
 135         sd_notifyf(false, "X_IMPORT_PROGRESS=%u", percent);
 136         log_info("Exported %u%%.", percent);
 137
 138         e->last_percent = percent;
 139 }
 140
 141 static int tar_export_process(TarExport *e) {
 142         ssize_t l;
 143         int r;
 144
 145         assert(e);
 146
 147         if (!e->tried_splice && e->compress.type == IMPORT_COMPRESS_UNCOMPRESSED) {
 148
 149                 l = splice(e->tar_fd, NULL, e->output_fd, NULL, COPY_BUFFER_SIZE, 0);
 150                 if (l < 0) {
 151                         if (errno == EAGAIN)
 152                                 return 0;
 153
 154                         e->tried_splice = true;
 155                 } else if (l == 0) {
 156                         r = 0;
 157                         goto finish;
 158                 } else {
 159                         e->written_uncompressed += l;
 160                         e->written_compressed += l;
 161
 162                         tar_export_report_progress(e);
 163
 164                         return 0;
 165                 }
 166         }
 167
 168         while (e->buffer_size <= 0) {
 169                 uint8_t input[COPY_BUFFER_SIZE];
 170
 171                 if (e->eof) {
 172                         r = 0;
 173                         goto finish;
 174                 }
 175
 176                 l = read(e->tar_fd, input, sizeof(input));
 177                 if (l < 0) {
 178                         r = log_error_errno(errno, "Failed to read tar file: %m");
 179                         goto finish;
 180                 }
 181
 182                 if (l == 0) {
 183                         e->eof = true;
 184                         r = import_compress_finish(&e->compress, &e->buffer, &e->buffer_size, &e->buffer_allocated);
 185                 } else {
 186                         e->written_uncompressed += l;
 187                         r = import_compress(&e->compress, input, l, &e->buffer, &e->buffer_size, &e->buffer_allocated);
 188                 }
 189                 if (r < 0) {
 190                         r = log_error_errno(r, "Failed to encode: %m");
 191                         goto finish;
 192                 }
 193         }
 194
 195         l = write(e->output_fd, e->buffer, e->buffer_size);
 196         if (l < 0) {
 197                 if (errno == EAGAIN)
 198                         return 0;
 199
 200                 r = log_error_errno(errno, "Failed to write output file: %m");
 201                 goto finish;
 202         }
 203
 204         assert((size_t) l <= e->buffer_size);
 205         memmove(e->buffer, (uint8_t*) e->buffer + l, e->buffer_size - l);
 206         e->buffer_size -= l;
 207         e->written_compressed += l;
 208
 209         tar_export_report_progress(e);
 210
 211         return 0;
 212
 213 finish:
 214         if (e->on_finished)
 215                 e->on_finished(e, r, e->userdata);
 216         else
 217                 sd_event_exit(e->event, r);
 218
 219         return 0;
 220 }
 221
 222 static int tar_export_on_output(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
 223         TarExport *i = userdata;
 224
 225         return tar_export_process(i);
 226 }
 227
 228 static int tar_export_on_defer(sd_event_source *s, void *userdata) {
 229         TarExport *i = userdata;
 230
 231         return tar_export_process(i);
 232 }
 233
 234 int tar_export_start(TarExport *e, const char *path, int fd, ImportCompressType compress) {
 235         _cleanup_close_ int sfd = -1;
 236         int r;
 237
 238         assert(e);
 239         assert(path);
 240         assert(fd >= 0);
 241         assert(compress < _IMPORT_COMPRESS_TYPE_MAX);
 242         assert(compress != IMPORT_COMPRESS_UNKNOWN);
 243
 244         if (e->output_fd >= 0)
 245                 return -EBUSY;
 246
 247         sfd = open(path, O_DIRECTORY|O_RDONLY|O_NOCTTY|O_CLOEXEC);
 248         if (sfd < 0)
 249                 return -errno;
 250
 251         if (fstat(sfd, &e->st) < 0)
 252                 return -errno;
 253
 254         r = fd_nonblock(fd, true);
 255         if (r < 0)
 256                 return r;
 257
 258         r = free_and_strdup(&e->path, path);
 259         if (r < 0)
 260                 return r;
 261
 262         e->quota_referenced = (uint64_t) -1;
 263
 264         if (e->st.st_ino == 256) { /* might be a btrfs subvolume? */
 265                 BtrfsQuotaInfo q;
 266
 267                 r = btrfs_subvol_get_subtree_quota_fd(sfd, 0, &q);
 268                 if (r >= 0)
 269                         e->quota_referenced = q.referenced;
 270
 271                 e->temp_path = mfree(e->temp_path);
 272
 273                 r = tempfn_random(path, NULL, &e->temp_path);
 274                 if (r < 0)
 275                         return r;
 276
 277                 /* Let's try to make a snapshot, if we can, so that the export is atomic */
 278                 r = btrfs_subvol_snapshot_fd(sfd, e->temp_path, BTRFS_SNAPSHOT_READ_ONLY|BTRFS_SNAPSHOT_RECURSIVE);
 279                 if (r < 0) {
 280                         log_debug_errno(r, "Couldn't create snapshot %s of %s, not exporting atomically: %m", e->temp_path, path);
 281                         e->temp_path = mfree(e->temp_path);
 282                 }
 283         }
 284
 285         r = import_compress_init(&e->compress, compress);
 286         if (r < 0)
 287                 return r;
 288
 289         r = sd_event_add_io(e->event, &e->output_event_source, fd, EPOLLOUT, tar_export_on_output, e);
 290         if (r == -EPERM) {
 291                 r = sd_event_add_defer(e->event, &e->output_event_source, tar_export_on_defer, e);
 292                 if (r < 0)
 293                         return r;
 294
 295                 r = sd_event_source_set_enabled(e->output_event_source, SD_EVENT_ON);
 296         }
 297         if (r < 0)
 298                 return r;
 299
 300         e->tar_fd = import_fork_tar_c(e->temp_path ?: e->path, &e->tar_pid);
 301         if (e->tar_fd < 0) {
 302                 e->output_event_source = sd_event_source_unref(e->output_event_source);
 303                 return e->tar_fd;
 304         }
 305
 306         e->output_fd = fd;
 307         return r;
 308 }