src/pstore/pstore.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 /* Copyright © 2019 Oracle and/or its affiliates. */
   4
   5 /* Generally speaking, the pstore contains a small number of files
   6  * that in turn contain a small amount of data.  */
   7 #include <errno.h>
   8 #include <stdio.h>
   9 #include <stdio_ext.h>
  10 #include <sys/prctl.h>
  11 #include <sys/xattr.h>
  12 #include <unistd.h>
  13
  14 #include "sd-daemon.h"
  15 #include "sd-journal.h"
  16 #include "sd-login.h"
  17 #include "sd-messages.h"
  18
  19 #include "acl-util.h"
  20 #include "alloc-util.h"
  21 #include "capability-util.h"
  22 #include "cgroup-util.h"
  23 #include "compress.h"
  24 #include "conf-parser.h"
  25 #include "copy.h"
  26 #include "dirent-util.h"
  27 #include "escape.h"
  28 #include "fd-util.h"
  29 #include "fileio.h"
  30 #include "fs-util.h"
  31 #include "io-util.h"
  32 #include "journal-importer.h"
  33 #include "log.h"
  34 #include "macro.h"
  35 #include "main-func.h"
  36 #include "mkdir.h"
  37 #include "parse-util.h"
  38 #include "process-util.h"
  39 #include "signal-util.h"
  40 #include "socket-util.h"
  41 #include "special.h"
  42 #include "sort-util.h"
  43 #include "string-table.h"
  44 #include "string-util.h"
  45 #include "strv.h"
  46 #include "tmpfile-util.h"
  47 #include "user-util.h"
  48 #include "util.h"
  49
  50 /* Command line argument handling */
  51 typedef enum PStoreStorage {
  52         PSTORE_STORAGE_NONE,
  53         PSTORE_STORAGE_EXTERNAL,
  54         PSTORE_STORAGE_JOURNAL,
  55         _PSTORE_STORAGE_MAX,
  56         _PSTORE_STORAGE_INVALID = -EINVAL,
  57 } PStoreStorage;
  58
  59 static const char* const pstore_storage_table[_PSTORE_STORAGE_MAX] = {
  60         [PSTORE_STORAGE_NONE] = "none",
  61         [PSTORE_STORAGE_EXTERNAL] = "external",
  62         [PSTORE_STORAGE_JOURNAL] = "journal",
  63 };
  64
  65 DEFINE_PRIVATE_STRING_TABLE_LOOKUP(pstore_storage, PStoreStorage);
  66 static DEFINE_CONFIG_PARSE_ENUM(config_parse_pstore_storage, pstore_storage, PStoreStorage, "Failed to parse storage setting");
  67
  68 static PStoreStorage arg_storage = PSTORE_STORAGE_EXTERNAL;
  69
  70 static bool arg_unlink = true;
  71 static const char *arg_sourcedir = "/sys/fs/pstore";
  72 static const char *arg_archivedir = "/var/lib/systemd/pstore";
  73
  74 static int parse_config(void) {
  75         static const ConfigTableItem items[] = {
  76                 { "PStore", "Unlink",  config_parse_bool,           0, &arg_unlink },
  77                 { "PStore", "Storage", config_parse_pstore_storage, 0, &arg_storage },
  78                 {}
  79         };
  80
  81         return config_parse_many_nulstr(
  82                         PKGSYSCONFDIR "/pstore.conf",
  83                         CONF_PATHS_NULSTR("systemd/pstore.conf.d"),
  84                         "PStore\0",
  85                         config_item_table_lookup, items,
  86                         CONFIG_PARSE_WARN,
  87                         NULL,
  88                         NULL);
  89 }
  90
  91 /* File list handling - PStoreEntry is the struct and
  92  * and PStoreEntry is the type that contains all info
  93  * about a pstore entry.  */
  94 typedef struct PStoreEntry {
  95         struct dirent dirent;
  96         bool is_binary;
  97         bool handled;
  98         char *content;
  99         size_t content_size;
 100 } PStoreEntry;
 101
 102 typedef struct PStoreList {
 103         PStoreEntry *entries;
 104         size_t n_entries;
 105 } PStoreList;
 106
 107 static void pstore_entries_reset(PStoreList *list) {
 108         for (size_t i = 0; i < list->n_entries; i++)
 109                 free(list->entries[i].content);
 110         free(list->entries);
 111         list->n_entries = 0;
 112 }
 113
 114 static int compare_pstore_entries(const PStoreEntry *a, const PStoreEntry *b) {
 115         return strcmp(a->dirent.d_name, b->dirent.d_name);
 116 }
 117
 118 static int move_file(PStoreEntry *pe, const char *subdir) {
 119         _cleanup_free_ char *ifd_path = NULL, *ofd_path = NULL;
 120         _cleanup_free_ void *field = NULL;
 121         const char *suffix, *message;
 122         struct iovec iovec[2];
 123         int n_iovec = 0, r;
 124
 125         if (pe->handled)
 126                 return 0;
 127
 128         ifd_path = path_join(arg_sourcedir, pe->dirent.d_name);
 129         if (!ifd_path)
 130                 return log_oom();
 131
 132         ofd_path = path_join(arg_archivedir, subdir, pe->dirent.d_name);
 133         if (!ofd_path)
 134                 return log_oom();
 135
 136         /* Always log to the journal */
 137         suffix = arg_storage == PSTORE_STORAGE_EXTERNAL ? strjoina(" moved to ", ofd_path) : (char *)".";
 138         message = strjoina("MESSAGE=PStore ", pe->dirent.d_name, suffix);
 139         iovec[n_iovec++] = IOVEC_MAKE_STRING(message);
 140
 141         if (pe->content_size > 0) {
 142                 size_t field_size;
 143
 144                 field_size = strlen("FILE=") + pe->content_size;
 145                 field = malloc(field_size);
 146                 if (!field)
 147                         return log_oom();
 148                 memcpy(stpcpy(field, "FILE="), pe->content, pe->content_size);
 149                 iovec[n_iovec++] = IOVEC_MAKE(field, field_size);
 150         }
 151
 152         r = sd_journal_sendv(iovec, n_iovec);
 153         if (r < 0)
 154                 return log_error_errno(r, "Failed to log pstore entry: %m");
 155
 156         if (arg_storage == PSTORE_STORAGE_EXTERNAL) {
 157                 /* Move file from pstore to external storage */
 158                 r = mkdir_parents(ofd_path, 0755);
 159                 if (r < 0)
 160                         return log_error_errno(r, "Failed to create directory %s: %m", ofd_path);
 161                 r = copy_file_atomic(ifd_path, ofd_path, 0600, 0, 0, COPY_REPLACE);
 162                 if (r < 0)
 163                         return log_error_errno(r, "Failed to copy_file_atomic: %s to %s", ifd_path, ofd_path);
 164         }
 165
 166         /* If file copied properly, remove it from pstore */
 167         if (arg_unlink)
 168                 (void) unlink(ifd_path);
 169
 170         pe->handled = true;
 171
 172         return 0;
 173 }
 174
 175 static int write_dmesg(const char *dmesg, size_t size, const char *id) {
 176         _cleanup_(unlink_and_freep) char *tmp_path = NULL;
 177         _cleanup_free_ char *ofd_path = NULL;
 178         _cleanup_close_ int ofd = -1;
 179         ssize_t wr;
 180         int r;
 181
 182         if (size == 0)
 183                 return 0;
 184
 185         assert(dmesg);
 186
 187         ofd_path = path_join(arg_archivedir, id, "dmesg.txt");
 188         if (!ofd_path)
 189                 return log_oom();
 190
 191         ofd = open_tmpfile_linkable(ofd_path, O_CLOEXEC|O_CREAT|O_TRUNC|O_WRONLY, &tmp_path);
 192         if (ofd < 0)
 193                 return log_error_errno(ofd, "Failed to open temporary file %s: %m", ofd_path);
 194         wr = write(ofd, dmesg, size);
 195         if (wr < 0)
 196                 return log_error_errno(errno, "Failed to store dmesg to %s: %m", ofd_path);
 197         if (wr != (ssize_t)size)
 198                 return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to store dmesg to %s. %zu bytes are lost.", ofd_path, size - wr);
 199         r = link_tmpfile(ofd, tmp_path, ofd_path);
 200         if (r < 0)
 201                 return log_error_errno(r, "Failed to write temporary file %s: %m", ofd_path);
 202         tmp_path = mfree(tmp_path);
 203
 204         return 0;
 205 }
 206
 207 static void process_dmesg_files(PStoreList *list) {
 208         /* Move files, reconstruct dmesg.txt */
 209         _cleanup_free_ char *dmesg = NULL, *dmesg_id = NULL;
 210         size_t dmesg_size = 0;
 211         bool dmesg_bad = false;
 212         PStoreEntry *pe;
 213
 214         /* Handle each dmesg file: files processed in reverse
 215          * order so as to properly reconstruct original dmesg */
 216         for (size_t n = list->n_entries; n > 0; n--) {
 217                 bool move_file_and_continue = false;
 218                 _cleanup_free_ char *pe_id = NULL;
 219                 char *p;
 220                 size_t plen;
 221
 222                 pe = &list->entries[n-1];
 223
 224                 if (pe->handled)
 225                         continue;
 226                 if (!startswith(pe->dirent.d_name, "dmesg-"))
 227                         continue;
 228
 229                 if (endswith(pe->dirent.d_name, ".enc.z")) /* indicates a problem */
 230                         move_file_and_continue = true;
 231                 p = strrchr(pe->dirent.d_name, '-');
 232                 if (!p)
 233                         move_file_and_continue = true;
 234
 235                 if (move_file_and_continue) {
 236                         /* A dmesg file on which we do NO additional processing */
 237                         (void) move_file(pe, NULL);
 238                         continue;
 239                 }
 240
 241                 /* See if this file is one of a related group of files
 242                  * in order to reconstruct dmesg */
 243
 244                 /* When dmesg is written into pstore, it is done so in
 245                  * small chunks, whatever the exchange buffer size is
 246                  * with the underlying pstore backend (ie. EFI may be
 247                  * ~2KiB), which means an example pstore with approximately
 248                  * 64KB of storage may have up to roughly 32 dmesg files
 249                  * that could be related, depending upon the size of the
 250                  * original dmesg.
 251                  *
 252                  * Here we look at the dmesg filename and try to discern
 253                  * if files are part of a related group, meaning the same
 254                  * original dmesg.
 255                  *
 256                  * The two known pstore backends are EFI and ERST. These
 257                  * backends store data in the Common Platform Error
 258                  * Record, CPER, format. The dmesg- filename contains the
 259                  * CPER record id, a 64bit number (in decimal notation).
 260                  * In Linux, the record id is encoded with two digits for
 261                  * the dmesg part (chunk) number and 3 digits for the
 262                  * count number. So allowing an additional digit to
 263                  * compensate for advancing time, this code ignores the
 264                  * last six digits of the filename in determining the
 265                  * record id.
 266                  *
 267                  * For the EFI backend, the record id encodes an id in the
 268                  * upper 32 bits, and a timestamp in the lower 32-bits.
 269                  * So ignoring the least significant 6 digits has proven
 270                  * to generally identify related dmesg entries.  */
 271 #define PSTORE_FILENAME_IGNORE 6
 272
 273                 /* determine common portion of record id */
 274                 ++p; /* move beyond dmesg- */
 275                 plen = strlen(p);
 276                 if (plen > PSTORE_FILENAME_IGNORE) {
 277                         pe_id = memdup_suffix0(p, plen - PSTORE_FILENAME_IGNORE);
 278                         if (!pe_id) {
 279                                 log_oom();
 280                                 return;
 281                         }
 282                 } else
 283                         pe_id = mfree(pe_id);
 284
 285                 /* Now move file from pstore to archive storage */
 286                 move_file(pe, pe_id);
 287
 288                 if (dmesg_bad)
 289                         continue;
 290
 291                 /* If the current record id is NOT the same as the
 292                  * previous record id, then start a new dmesg.txt file */
 293                 if (!streq_ptr(pe_id, dmesg_id)) {
 294                         /* Encountered a new dmesg group, close out old one, open new one */
 295                         (void) write_dmesg(dmesg, dmesg_size, dmesg_id);
 296                         dmesg_size = 0;
 297
 298                         /* now point dmesg_id to storage of pe_id */
 299                         free_and_replace(dmesg_id, pe_id);
 300                 }
 301
 302                 /* Reconstruction of dmesg is done as a useful courtesy: do not fail, but don't write garbled
 303                  * output either. */
 304                 size_t needed = strlen(pe->dirent.d_name) + strlen(":\n") + pe->content_size + 1;
 305                 if (!GREEDY_REALLOC(dmesg, dmesg_size + needed)) {
 306                         log_oom();
 307                         dmesg_bad = true;
 308                         continue;
 309                 }
 310
 311                 dmesg_size += sprintf(dmesg + dmesg_size, "%s:\n", pe->dirent.d_name);
 312                 if (pe->content) {
 313                         memcpy(dmesg + dmesg_size, pe->content, pe->content_size);
 314                         dmesg_size += pe->content_size;
 315                 }
 316
 317                 pe_id = mfree(pe_id);
 318         }
 319
 320         if (!dmesg_bad)
 321                 (void) write_dmesg(dmesg, dmesg_size, dmesg_id);
 322 }
 323
 324 static int list_files(PStoreList *list, const char *sourcepath) {
 325         _cleanup_(closedirp) DIR *dirp = NULL;
 326         int r;
 327
 328         dirp = opendir(sourcepath);
 329         if (!dirp)
 330                 return log_error_errno(errno, "Failed to opendir %s: %m", sourcepath);
 331
 332         FOREACH_DIRENT(de, dirp, return log_error_errno(errno, "Failed to iterate through %s: %m", sourcepath)) {
 333                 _cleanup_free_ char *ifd_path = NULL;
 334
 335                 ifd_path = path_join(sourcepath, de->d_name);
 336                 if (!ifd_path)
 337                         return log_oom();
 338
 339                 _cleanup_free_ char *buf = NULL;
 340                 size_t buf_size;
 341
 342                 /* Now read contents of pstore file */
 343                 r = read_full_virtual_file(ifd_path, &buf, &buf_size);
 344                 if (r < 0) {
 345                         log_warning_errno(r, "Failed to read file %s, skipping: %m", ifd_path);
 346                         continue;
 347                 }
 348
 349                 if (!GREEDY_REALLOC(list->entries, list->n_entries + 1))
 350                         return log_oom();
 351
 352                 list->entries[list->n_entries++] = (PStoreEntry) {
 353                         .dirent = *de,
 354                         .content = TAKE_PTR(buf),
 355                         .content_size = buf_size,
 356                         .is_binary = true,
 357                         .handled = false,
 358                 };
 359         }
 360
 361         return 0;
 362 }
 363
 364 static int run(int argc, char *argv[]) {
 365         _cleanup_(pstore_entries_reset) PStoreList list = {};
 366         int r;
 367
 368         log_setup();
 369
 370         if (argc == 3) {
 371                 arg_sourcedir = argv[1];
 372                 arg_archivedir = argv[2];
 373         } else if (argc > 1)
 374                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
 375                                        "This program takes zero or two arguments.");
 376
 377         /* Ignore all parse errors */
 378         (void) parse_config();
 379
 380         log_debug("Selected storage: %s.", pstore_storage_to_string(arg_storage));
 381         log_debug("Selected unlink: %s.", yes_no(arg_unlink));
 382
 383         if (arg_storage == PSTORE_STORAGE_NONE)
 384                 /* Do nothing, intentionally, leaving pstore untouched */
 385                 return 0;
 386
 387         /* Obtain list of files in pstore */
 388         r = list_files(&list, arg_sourcedir);
 389         if (r < 0)
 390                 return r;
 391
 392         /* Handle each pstore file */
 393         /* Sort files lexigraphically ascending, generally needed by all */
 394         typesafe_qsort(list.entries, list.n_entries, compare_pstore_entries);
 395
 396         /* Process known file types */
 397         process_dmesg_files(&list);
 398
 399         /* Move left over files out of pstore */
 400         for (size_t n = 0; n < list.n_entries; n++)
 401                 move_file(&list.entries[n], NULL);
 402
 403         return 0;
 404 }
 405
 406 DEFINE_MAIN_FUNCTION(run);