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