src/logutil/logutil.c

   1 /*
   2  * Copyright (c) 2005-2008, The Android Open Source Project
   3  * Copyright (c) 2009-2013, Samsung Electronics Co., Ltd. All rights reserved.
   4  *
   5  * Licensed under the Apache License, Version 2.0 (the "License");
   6  * you may not use this file except in compliance with the License.
   7  * You may obtain a copy of the License at
   8  *
   9  *      http://www.apache.org/licenses/LICENSE-2.0
  10  *
  11  * Unless required by applicable law or agreed to in writing, software
  12  * distributed under the License is distributed on an "AS IS" BASIS,
  13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14  * See the License for the specific language governing permissions and
  15  * limitations under the License.
  16  */
  17 #define _GNU_SOURCE
  18
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <stdbool.h>
  22 #include <stdarg.h>
  23 #include <string.h>
  24 #include <unistd.h>
  25 #include <fcntl.h>
  26 #include <time.h>
  27 #include <sys/time.h>
  28 #include <ctype.h>
  29 #include <errno.h>
  30 #include <assert.h>
  31 #include <sys/stat.h>
  32 #include <arpa/inet.h>
  33
  34
  35 #include <logger.h>
  36 #include <logprint.h>
  37
  38 #define DEFAULT_LOG_ROTATE_SIZE_KBYTES 16
  39 #define DEFAULT_MAX_ROTATED_LOGS 4
  40 #define MAX_QUEUED 4096
  41 #define LOG_FILE_DIR    "/dev/log_"
  42
  43 static log_format* g_logformat;
  44 static bool g_nonblock = false;
  45 static int g_tail_lines = 0;
  46
  47 static const char * g_output_filename = NULL;
  48 static int g_log_rotate_size_kbytes = 0;                   // 0 means "no log rotation"
  49 static int g_max_rotated_logs = DEFAULT_MAX_ROTATED_LOGS; // 0 means "unbounded"
  50 static int g_outfd = -1;
  51 static off_t g_out_byte_count = 0;
  52 static int g_dev_count = 0;
  53
  54 struct queued_entry_t {
  55         union {
  56                 unsigned char buf[LOGGER_ENTRY_MAX_LEN + 1] __attribute__((aligned(4)));
  57                 struct logger_entry entry __attribute__((aligned(4)));
  58         };
  59         struct queued_entry_t* next;
  60 };
  61
  62 static int cmp(struct queued_entry_t* a, struct queued_entry_t* b)
  63 {
  64         int n = a->entry.sec - b->entry.sec;
  65         if (n != 0) {
  66                 return n;
  67         }
  68         return a->entry.nsec - b->entry.nsec;
  69 }
  70
  71
  72 struct log_device_t {
  73         char* device;
  74         int fd;
  75         bool printed;
  76         struct queued_entry_t* queue;
  77         struct log_device_t* next;
  78 };
  79
  80 static void enqueue(struct log_device_t* device, struct queued_entry_t* entry)
  81 {
  82         if (device->queue == NULL) {
  83                 device->queue = entry;
  84         } else {
  85                 struct queued_entry_t** e = &device->queue;
  86                 while (*e && cmp(entry, *e) >= 0 ) {
  87                         e = &((*e)->next);
  88                 }
  89                 entry->next = *e;
  90                 *e = entry;
  91         }
  92 }
  93
  94 static int open_logfile (const char *pathname)
  95 {
  96         return open(pathname, O_WRONLY | O_APPEND | O_CREAT, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH);
  97 }
  98
  99 static void rotate_logs()
 100 {
 101         int err;
 102         int i;
 103         char file0[256]={0};
 104         char file1[256]={0};
 105
 106         // Can't rotate logs if we're not outputting to a file
 107         if (g_output_filename == NULL) {
 108                 return;
 109         }
 110
 111         close(g_outfd);
 112
 113         for (i = g_max_rotated_logs ; i > 0 ; i--) {
 114                 snprintf(file1, 255, "%s.%d", g_output_filename, i);
 115
 116                 if (i - 1 == 0) {
 117                         snprintf(file0, 255, "%s", g_output_filename);
 118                 } else {
 119                         snprintf(file0, 255, "%s.%d", g_output_filename, i - 1);
 120                 }
 121
 122                 err = rename (file0, file1);
 123
 124                 if (err < 0 && errno != ENOENT) {
 125                         perror("while rotating log files");
 126                 }
 127         }
 128
 129         g_outfd = open_logfile (g_output_filename);
 130
 131         if (g_outfd < 0) {
 132                 perror ("couldn't open output file");
 133                 exit(-1);
 134         }
 135
 136         g_out_byte_count = 0;
 137
 138 }
 139
 140
 141 static void processBuffer(struct log_device_t* dev, struct logger_entry *buf)
 142 {
 143         int bytes_written = 0;
 144         int err;
 145         log_entry entry;
 146         char mgs_buf[1024];
 147
 148         err = log_process_log_buffer(buf, &entry);
 149
 150         if (err < 0) {
 151                 goto error;
 152         }
 153
 154         if (log_should_print_line(g_logformat, entry.tag, entry.priority)) {
 155                 if (false && g_dev_count > 1) {
 156                         mgs_buf[0] = dev->device[0];
 157                         mgs_buf[1] = ' ';
 158                         bytes_written = write(g_outfd, mgs_buf, 2);
 159                         if (bytes_written < 0) {
 160                                 perror("output error");
 161                                 exit(-1);
 162                         }
 163                 }
 164
 165                 bytes_written = log_print_log_line(g_logformat, g_outfd, &entry);
 166
 167                 if (bytes_written < 0) {
 168                         perror("output error");
 169                         exit(-1);
 170                 }
 171         }
 172
 173         g_out_byte_count += bytes_written;
 174
 175         if (g_log_rotate_size_kbytes > 0 && (g_out_byte_count / 1024) >= g_log_rotate_size_kbytes) {
 176                 if (g_nonblock) {
 177                         exit(0);
 178                 } else {
 179                         rotate_logs();
 180                 }
 181         }
 182
 183 error:
 184         return;
 185 }
 186
 187 static void chooseFirst(struct log_device_t* dev, struct log_device_t** firstdev)
 188 {
 189         for (*firstdev = NULL; dev != NULL; dev = dev->next) {
 190                 if (dev->queue != NULL && (*firstdev == NULL ||
 191                                         cmp(dev->queue, (*firstdev)->queue) < 0)) {
 192                         *firstdev = dev;
 193                 }
 194         }
 195 }
 196
 197 static void maybePrintStart(struct log_device_t* dev) {
 198         if (!dev->printed) {
 199                 dev->printed = true;
 200                 if (g_dev_count > 1 ) {
 201                         char buf[1024];
 202                         snprintf(buf, sizeof(buf), "--------- beginning of %s\n", dev->device);
 203                         if (write(g_outfd, buf, strlen(buf)) < 0) {
 204                                 perror("output error");
 205                                 exit(-1);
 206                         }
 207                 }
 208         }
 209 }
 210
 211 static void skipNextEntry(struct log_device_t* dev) {
 212         maybePrintStart(dev);
 213         struct queued_entry_t* entry = dev->queue;
 214         dev->queue = entry->next;
 215         free(entry);
 216 }
 217
 218 static void printNextEntry(struct log_device_t* dev)
 219 {
 220         maybePrintStart(dev);
 221         processBuffer(dev, &dev->queue->entry);
 222         skipNextEntry(dev);
 223 }
 224
 225
 226 static void read_log_lines(struct log_device_t* devices)
 227 {
 228         struct log_device_t* dev;
 229         int max = 0;
 230         int ret;
 231         int queued_lines = 0;
 232         bool sleep = false; // for exit immediately when log buffer is empty and g_nonblock value is true.
 233
 234         int result;
 235         fd_set readset;
 236
 237         for (dev=devices; dev; dev = dev->next) {
 238                 if (dev->fd > max) {
 239                         max = dev->fd;
 240                 }
 241         }
 242
 243         while (1) {
 244                 do {
 245                         struct timeval timeout = { 0, 5000 /* 5ms */ }; // If we oversleep it's ok, i.e. ignore EINTR.
 246                         FD_ZERO(&readset);
 247                         for (dev=devices; dev; dev = dev->next) {
 248                                 FD_SET(dev->fd, &readset);
 249                         }
 250                         result = select(max + 1, &readset, NULL, NULL, sleep ? NULL : &timeout);
 251                 } while (result == -1 && errno == EINTR);
 252
 253                 if (result >= 0) {
 254                         for (dev=devices; dev; dev = dev->next) {
 255                                 if (FD_ISSET(dev->fd, &readset)) {
 256                                         struct queued_entry_t* entry = (struct queued_entry_t *)malloc(sizeof( struct queued_entry_t));
 257                                         if (entry == NULL) {
 258                                                 fprintf(stderr,"Can't malloc queued_entry\n");
 259                                                 exit(-1);
 260                                         }
 261                                         entry->next = NULL;
 262
 263                                         /* NOTE: driver guarantees we read exactly one full entry */
 264                                         ret = read(dev->fd, entry->buf, LOGGER_ENTRY_MAX_LEN);
 265                                         if (ret < 0) {
 266                                                 if (errno == EINTR) {
 267                                                         free(entry);
 268                                                         goto next;
 269                                                 }
 270                                                 if (errno == EAGAIN) {
 271                                                         free(entry);
 272                                                         break;
 273                                                 }
 274                                                 perror("dlogutil read");
 275                                                 exit(EXIT_FAILURE);
 276                                         }
 277                                         else if (!ret) {
 278                                                 free(entry);
 279                                                 fprintf(stderr, "read: Unexpected EOF!\n");
 280                                                 exit(EXIT_FAILURE);
 281                                         }
 282                                         else if (entry->entry.len != ret - sizeof(struct logger_entry)) {
 283                                                 fprintf(stderr, "read: unexpected length. Expected %d, got %d\n",
 284                                                                 entry->entry.len, ret - sizeof(struct logger_entry));
 285                                                 free(entry);
 286                                                 exit(EXIT_FAILURE);
 287                                         }
 288
 289
 290                                         entry->entry.msg[entry->entry.len] = '\0';
 291
 292                                         enqueue(dev, entry);
 293                                         ++queued_lines;
 294                                         if (g_nonblock && MAX_QUEUED < queued_lines) {
 295                                                 while (true) {
 296                                                         chooseFirst(devices, &dev);
 297                                                         if (dev == NULL)
 298                                                                 break;
 299                                                         printNextEntry(dev);
 300                                                         --queued_lines;
 301                                                 }
 302                                                 break;
 303                                         }
 304                                 }
 305                         }
 306
 307                         if (result == 0) {
 308                                 /* we did our short timeout trick and there's nothing new
 309                                  print everything we have and wait for more data */
 310                                 sleep = true;
 311                                 while (true) {
 312                                         chooseFirst(devices, &dev);
 313                                         if (dev == NULL) {
 314                                                 break;
 315                                         }
 316                                         if (g_tail_lines == 0 || queued_lines <= g_tail_lines) {
 317                                                 printNextEntry(dev);
 318                                         } else {
 319                                                 skipNextEntry(dev);
 320                                         }
 321                                         --queued_lines;
 322                                 }
 323
 324                                 /* the caller requested to just dump the log and exit */
 325                                 if (g_nonblock) {
 326                                         exit(0);
 327                                 }
 328                         } else {
 329                                 /* print all that aren't the last in their list */
 330                                 sleep = false;
 331                                 while (g_tail_lines == 0 || queued_lines > g_tail_lines) {
 332                                         chooseFirst(devices, &dev);
 333                                         if (dev == NULL || dev->queue->next == NULL) {
 334                                                 break;
 335                                         }
 336                                         if (g_tail_lines == 0) {
 337                                                 printNextEntry(dev);
 338                                         } else {
 339                                                 skipNextEntry(dev);
 340                                         }
 341                                         --queued_lines;
 342                                 }
 343                         }
 344                 }
 345 next:
 346                 ;
 347         }
 348 }
 349
 350
 351 static int clear_log(int logfd)
 352 {
 353         return ioctl(logfd, LOGGER_FLUSH_LOG);
 354 }
 355
 356 /* returns the total size of the log's ring buffer */
 357 static int get_log_size(int logfd)
 358 {
 359         return ioctl(logfd, LOGGER_GET_LOG_BUF_SIZE);
 360 }
 361
 362 /* returns the readable size of the log's ring buffer (that is, amount of the log consumed) */
 363 static int get_log_readable_size(int logfd)
 364 {
 365         return ioctl(logfd, LOGGER_GET_LOG_LEN);
 366 }
 367
 368 static void setup_output()
 369 {
 370
 371         if (g_output_filename == NULL) {
 372                 g_outfd = STDOUT_FILENO;
 373
 374         } else {
 375                 struct stat statbuf;
 376
 377                 g_outfd = open_logfile (g_output_filename);
 378
 379                 if (g_outfd < 0) {
 380                         perror ("couldn't open output file");
 381                         exit(-1);
 382                 }
 383                 if (fstat(g_outfd, &statbuf) == -1)
 384                         g_out_byte_count = 0;
 385                 else
 386                         g_out_byte_count = statbuf.st_size;
 387         }
 388 }
 389
 390 static int set_log_format(const char * formatString)
 391 {
 392         static log_print_format format;
 393
 394         format = log_format_from_string(formatString);
 395
 396         if (format == FORMAT_OFF) {
 397                 /* FORMAT_OFF means invalid string */
 398                 return -1;
 399         }
 400
 401         log_set_print_format(g_logformat, format);
 402
 403         return 0;
 404 }
 405
 406 static void show_help(const char *cmd)
 407 {
 408         fprintf(stderr,"Usage: %s [options] [filterspecs]\n", cmd);
 409
 410         fprintf(stderr, "options include:\n"
 411                         "  -s              Set default filter to silent.\n"
 412                         "                  Like specifying filterspec '*:s'\n"
 413                         "  -f <filename>   Log to file. Default to stdout\n"
 414                         "  -r [<kbytes>]   Rotate log every kbytes. (16 if unspecified). Requires -f\n"
 415                         "  -n <count>      Sets max number of rotated logs to <count>, default 4\n"
 416                         "  -v <format>     Sets the log print format, where <format> is one of:\n\n"
 417                         "                  brief(by default) process tag thread raw time threadtime long\n\n"
 418                         "  -c              clear (flush) the entire log and exit, conflicts with '-g'\n"
 419                         "  -d              dump the log and then exit (don't block)\n"
 420                         "  -t <count>      print only the most recent <count> lines (implies -d)\n"
 421                         "  -g              get the size of the log's ring buffer and exit, conflicts with '-c'\n"
 422                         "  -b <buffer>     request alternate ring buffer\n"
 423                         "                  ('main' (default), 'radio', 'system')");
 424
 425
 426         fprintf(stderr,"\nfilterspecs are a series of \n"
 427                         "  <tag>[:priority]\n\n"
 428                         "where <tag> is a log component tag (or * for all) and priority is:\n"
 429                         "  V    Verbose\n"
 430                         "  D    Debug\n"
 431                         "  I    Info\n"
 432                         "  W    Warn\n"
 433                         "  E    Error\n"
 434                         "  F    Fatal\n"
 435                         "  S    Silent (supress all output)\n"
 436                         "\n'*' means '*:D' and <tag> by itself means <tag>:V\n"
 437                         "If no filterspec is found, filter defaults to '*:I'\n\n");
 438 }
 439
 440
 441 /*
 442  * free one log_device_t and it doesn't take care of chain so it
 443  * may break the chain list
 444  */
 445 static void log_devices_free(struct log_device_t *dev)
 446 {
 447         if (!dev)
 448                 return;
 449
 450         if (dev->device)
 451                 free(dev->device);
 452
 453         if (dev->queue) {
 454                 while (dev->queue->next) {
 455                         struct queued_entry_t *tmp = dev->queue->next;
 456                         dev->queue->next = tmp->next;
 457                         free(tmp);
 458                 }
 459                 free(dev->queue);
 460         }
 461
 462         free(dev);
 463         dev = NULL;
 464 }
 465
 466
 467 /*
 468  * free all the nodes after the "dev" and includes itself
 469  */
 470 static void log_devices_chain_free(struct log_device_t *dev)
 471 {
 472         if (!dev)
 473                 return;
 474
 475         while (dev->next) {
 476                 struct log_device_t *tmp = dev->next;
 477                 dev->next = tmp->next;
 478                 log_devices_free(tmp);
 479         }
 480
 481         log_devices_free(dev);
 482         dev = NULL;
 483 }
 484
 485
 486 /*
 487  * create a new log_device_t instance but don't care about
 488  * the device node accessable or not
 489  */
 490 static struct log_device_t *log_devices_new(const char *path)
 491 {
 492         struct log_device_t *new;
 493
 494         if (!path || strlen(path) <= 0)
 495                 return NULL;
 496
 497         new = malloc(sizeof(*new));
 498         if (!new) {
 499                 fprintf(stderr, "out of memory\n");
 500                 return NULL;
 501         }
 502
 503         new->device = strdup(path);
 504         new->fd = -1;
 505         new->printed = false;
 506         new->queue = NULL;
 507         new->next = NULL;
 508
 509         return new;
 510 }
 511
 512
 513 /*
 514  * add a new device to the tail of chain
 515  */
 516 static int log_devices_add_to_tail(struct log_device_t *devices, struct log_device_t *new)
 517 {
 518         struct log_device_t *tail = devices;
 519
 520         if (!devices || !new)
 521                 return -1;
 522
 523         while (tail->next)
 524                 tail = tail->next;
 525
 526         tail->next = new;
 527         g_dev_count++;
 528
 529         return 0;
 530 }
 531
 532 int main(int argc, char **argv)
 533 {
 534         int err;
 535         int has_set_log_format = 0;
 536         int is_clear_log = 0;
 537         int getLogSize = 0;
 538         int mode = O_RDONLY;
 539         int accessmode = R_OK;
 540         int i;
 541         struct log_device_t* devices = NULL;
 542         struct log_device_t* dev;
 543
 544         g_logformat = (log_format *)log_format_new();
 545
 546         if (argc == 2 && 0 == strcmp(argv[1], "--test")) {
 547                 logprint_run_tests();
 548                 exit(0);
 549         }
 550
 551         if (argc == 2 && 0 == strcmp(argv[1], "--help")) {
 552                 show_help(argv[0]);
 553                 exit(0);
 554         }
 555
 556         for (;;) {
 557                 int ret;
 558
 559                 ret = getopt(argc, argv, "cdt:gsf:r:n:v:b:D");
 560
 561                 if (ret < 0) {
 562                         break;
 563                 }
 564
 565                 switch(ret) {
 566                         case 's':
 567                                 /* default to all silent */
 568                                 log_add_filter_rule(g_logformat, "*:s");
 569                                 break;
 570
 571                         case 'c':
 572                                 is_clear_log = 1;
 573                                 mode = O_WRONLY;
 574                                 break;
 575
 576                         case 'd':
 577                                 g_nonblock = true;
 578                                 break;
 579
 580                         case 't':
 581                                 g_nonblock = true;
 582                                 g_tail_lines = atoi(optarg);
 583                                 break;
 584
 585
 586                         case 'g':
 587                                 getLogSize = 1;
 588                                 break;
 589
 590                         case 'b': {
 591                                                   char *buf;
 592                                                   if (asprintf(&buf, LOG_FILE_DIR "%s", optarg) == -1) {
 593                                                           fprintf(stderr,"Can't malloc LOG_FILE_DIR\n");
 594                                                           exit(-1);
 595                                                   }
 596
 597                                                   dev = log_devices_new(buf);
 598                                                   if (dev == NULL) {
 599                                                           fprintf(stderr,"Can't add log device: %s\n", buf);
 600                                                           exit(-1);
 601                                                   }
 602                                                   if (devices) {
 603                                                           if (log_devices_add_to_tail(devices, dev)) {
 604                                                                   fprintf(stderr, "Open log device %s failed\n", buf);
 605                                                                   exit(-1);
 606                                                           }
 607                                                   } else {
 608                                                           devices = dev;
 609                                                           g_dev_count = 1;
 610                                                   }
 611                                           }
 612                                           break;
 613
 614                         case 'f':
 615                                           /* redirect output to a file */
 616                                           g_output_filename = optarg;
 617
 618                                           break;
 619
 620                         case 'r':
 621                                           if (!isdigit(optarg[0])) {
 622                                                   fprintf(stderr,"Invalid parameter to -r\n");
 623                                                   show_help(argv[0]);
 624                                                   exit(-1);
 625                                           }
 626                                           g_log_rotate_size_kbytes = atoi(optarg);
 627                                           break;
 628
 629                         case 'n':
 630                                           if (!isdigit(optarg[0])) {
 631                                                   fprintf(stderr,"Invalid parameter to -r\n");
 632                                                   show_help(argv[0]);
 633                                                   exit(-1);
 634                                           }
 635
 636                                           g_max_rotated_logs = atoi(optarg);
 637                                           break;
 638
 639                         case 'v':
 640                                           err = set_log_format (optarg);
 641                                           if (err < 0) {
 642                                                   fprintf(stderr,"Invalid parameter to -v\n");
 643                                                   show_help(argv[0]);
 644                                                   exit(-1);
 645                                           }
 646
 647                                           has_set_log_format = 1;
 648                                           break;
 649
 650                         default:
 651                                           fprintf(stderr,"Unrecognized Option\n");
 652                                           show_help(argv[0]);
 653                                           exit(-1);
 654                                           break;
 655                 }
 656         }
 657
 658         /* get log size conflicts with write mode */
 659         if (getLogSize && mode != O_RDONLY) {
 660                 show_help(argv[0]);
 661                 exit(-1);
 662         }
 663
 664         if (!devices) {
 665                 devices = log_devices_new("/dev/"LOGGER_LOG_MAIN);
 666                 if (devices == NULL) {
 667                         fprintf(stderr,"Can't add log device: %s\n", LOGGER_LOG_MAIN);
 668                         exit(-1);
 669                 }
 670                 g_dev_count = 1;
 671
 672                 if (mode == O_WRONLY)
 673                         accessmode = W_OK;
 674
 675                 /* only add this if it's available */
 676                 if (0 == access("/dev/"LOGGER_LOG_SYSTEM, accessmode)) {
 677                         if (log_devices_add_to_tail(devices, log_devices_new("/dev/"LOGGER_LOG_SYSTEM))) {
 678                                 fprintf(stderr,"Can't add log device: %s\n", LOGGER_LOG_SYSTEM);
 679                                 exit(-1);
 680                         }
 681                 }
 682                 if (0 == access("/dev/"LOGGER_LOG_APPS, accessmode)) {
 683                         if (log_devices_add_to_tail(devices, log_devices_new("/dev/"LOGGER_LOG_APPS))) {
 684                                 fprintf(stderr,"Can't add log device: %s\n", LOGGER_LOG_APPS);
 685                                 exit(-1);
 686                         }
 687                 }
 688
 689         }
 690
 691         if (g_log_rotate_size_kbytes != 0 && g_output_filename == NULL)
 692         {
 693                 fprintf(stderr,"-r requires -f as well\n");
 694                 show_help(argv[0]);
 695                 exit(-1);
 696         }
 697
 698         setup_output();
 699
 700
 701         if (has_set_log_format == 0) {
 702                 err = set_log_format("brief");
 703         }
 704         fprintf(stderr,"arc = %d, optind = %d ,Kb %d, rotate %d\n", argc, optind,g_log_rotate_size_kbytes,g_max_rotated_logs);
 705
 706         if(argc == optind ) {
 707                 /* Add from environment variable
 708                 char *env_tags_orig = getenv("DLOG_TAGS");*/
 709                 log_add_filter_string(g_logformat, "*:d");
 710         } else {
 711
 712                 for (i = optind ; i < argc ; i++) {
 713                         err = log_add_filter_string(g_logformat, argv[i]);
 714
 715                         if (err < 0) {
 716                                 fprintf (stderr, "Invalid filter expression '%s'\n", argv[i]);
 717                                 show_help(argv[0]);
 718                                 exit(-1);
 719                         }
 720                 }
 721         }
 722         dev = devices;
 723         while (dev) {
 724                 dev->fd = open(dev->device, mode);
 725                 if (dev->fd < 0) {
 726                         fprintf(stderr, "Unable to open log device '%s': %s\n",
 727                                         dev->device, strerror(errno));
 728                         exit(EXIT_FAILURE);
 729                 }
 730
 731                 if (is_clear_log) {
 732                         int ret;
 733                         ret = clear_log(dev->fd);
 734                         if (ret) {
 735                                 perror("ioctl");
 736                                 exit(EXIT_FAILURE);
 737                         }
 738                 }
 739
 740                 if (getLogSize) {
 741                         int size, readable;
 742
 743                         size = get_log_size(dev->fd);
 744                         if (size < 0) {
 745                                 perror("ioctl");
 746                                 exit(EXIT_FAILURE);
 747                         }
 748
 749                         readable = get_log_readable_size(dev->fd);
 750                         if (readable < 0) {
 751                                 perror("ioctl");
 752                                 exit(EXIT_FAILURE);
 753                         }
 754
 755                         printf("%s: ring buffer is %dKb (%dKb consumed), "
 756                                         "max entry is %db, max payload is %db\n", dev->device,
 757                                         size / 1024, readable / 1024,
 758                                         (int) LOGGER_ENTRY_MAX_LEN, (int) LOGGER_ENTRY_MAX_PAYLOAD);
 759                 }
 760
 761                 dev = dev->next;
 762         }
 763
 764         if (getLogSize) {
 765                 return 0;
 766         }
 767
 768         if (is_clear_log) {
 769                 return 0;
 770         }
 771
 772         read_log_lines(devices);
 773
 774         log_devices_chain_free(devices);
 775
 776         return 0;
 777 }