src/libsystemd/sd-bus/bus-dump.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2013 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include "util.h"
  23 #include "capability.h"
  24 #include "strv.h"
  25 #include "audit.h"
  26 #include "macro.h"
  27
  28 #include "bus-message.h"
  29 #include "bus-internal.h"
  30 #include "bus-type.h"
  31 #include "bus-dump.h"
  32
  33 static char *indent(unsigned level, unsigned flags) {
  34         char *p;
  35         unsigned n, i = 0;
  36
  37         n = 0;
  38
  39         if (flags & BUS_MESSAGE_DUMP_SUBTREE_ONLY && level > 0)
  40                 level -= 1;
  41
  42         if (flags & BUS_MESSAGE_DUMP_WITH_HEADER)
  43                 n += 2;
  44
  45         p = new(char, n + level*8 + 1);
  46         if (!p)
  47                 return NULL;
  48
  49         if (flags & BUS_MESSAGE_DUMP_WITH_HEADER) {
  50                 p[i++] = ' ';
  51                 p[i++] = ' ';
  52         }
  53
  54         memset(p + i, ' ', level*8);
  55         p[i + level*8] = 0;
  56
  57         return p;
  58 }
  59
  60 int bus_message_dump(sd_bus_message *m, FILE *f, unsigned flags) {
  61         unsigned level = 1;
  62         int r;
  63
  64         assert(m);
  65
  66         if (!f)
  67                 f = stdout;
  68
  69         if (flags & BUS_MESSAGE_DUMP_WITH_HEADER) {
  70                 fprintf(f,
  71                         "%s%s%s Type=%s%s%s  Endian=%c  Flags=%u  Version=%u  Priority=%lli",
  72                         m->header->type == SD_BUS_MESSAGE_METHOD_ERROR ? ansi_highlight_red() :
  73                         m->header->type == SD_BUS_MESSAGE_METHOD_RETURN ? ansi_highlight_green() :
  74                         m->header->type != SD_BUS_MESSAGE_SIGNAL ? ansi_highlight() : "", draw_special_char(DRAW_TRIANGULAR_BULLET), ansi_highlight_off(),
  75                         ansi_highlight(), bus_message_type_to_string(m->header->type), ansi_highlight_off(),
  76                         m->header->endian,
  77                         m->header->flags,
  78                         m->header->version,
  79                         (long long) m->priority);
  80
  81                 /* Display synthetic message serial number in a more readable
  82                  * format than (uint32_t) -1 */
  83                 if (BUS_MESSAGE_COOKIE(m) == 0xFFFFFFFFULL)
  84                         fprintf(f, " Cookie=-1");
  85                 else
  86                         fprintf(f, " Cookie=%" PRIu64, BUS_MESSAGE_COOKIE(m));
  87
  88                 if (m->reply_cookie != 0)
  89                         fprintf(f, "  ReplyCookie=%" PRIu64, m->reply_cookie);
  90
  91                 fputs("\n", f);
  92
  93                 if (m->sender)
  94                         fprintf(f, "  Sender=%s%s%s", ansi_highlight(), m->sender, ansi_highlight_off());
  95                 if (m->destination)
  96                         fprintf(f, "  Destination=%s%s%s", ansi_highlight(), m->destination, ansi_highlight_off());
  97                 if (m->path)
  98                         fprintf(f, "  Path=%s%s%s", ansi_highlight(), m->path, ansi_highlight_off());
  99                 if (m->interface)
 100                         fprintf(f, "  Interface=%s%s%s", ansi_highlight(), m->interface, ansi_highlight_off());
 101                 if (m->member)
 102                         fprintf(f, "  Member=%s%s%s", ansi_highlight(), m->member, ansi_highlight_off());
 103
 104                 if (m->sender || m->destination || m->path || m->interface || m->member)
 105                         fputs("\n", f);
 106
 107                 if (sd_bus_error_is_set(&m->error))
 108                         fprintf(f,
 109                                 "  ErrorName=%s%s%s"
 110                                 "  ErrorMessage=%s\"%s\"%s\n",
 111                                 ansi_highlight_red(), strna(m->error.name), ansi_highlight_off(),
 112                                 ansi_highlight_red(), strna(m->error.message), ansi_highlight_off());
 113
 114                 if (m->monotonic != 0)
 115                         fprintf(f, "  Monotonic="USEC_FMT, m->monotonic);
 116                 if (m->realtime != 0)
 117                         fprintf(f, "  Realtime="USEC_FMT, m->realtime);
 118                 if (m->seqnum != 0)
 119                         fprintf(f, "  SequenceNumber=%"PRIu64, m->seqnum);
 120
 121                 if (m->monotonic != 0 || m->realtime != 0 || m->seqnum != 0)
 122                         fputs("\n", f);
 123
 124                 bus_creds_dump(&m->creds, f, true);
 125         }
 126
 127         r = sd_bus_message_rewind(m, !(flags & BUS_MESSAGE_DUMP_SUBTREE_ONLY));
 128         if (r < 0) {
 129                 log_error("Failed to rewind: %s", strerror(-r));
 130                 return r;
 131         }
 132
 133         if (!(flags & BUS_MESSAGE_DUMP_SUBTREE_ONLY))
 134                 fprintf(f, "%sMESSAGE \"%s\" {\n", indent(0, flags), strempty(m->root_container.signature));
 135
 136         for (;;) {
 137                 _cleanup_free_ char *prefix = NULL;
 138                 const char *contents = NULL;
 139                 char type;
 140                 union {
 141                         uint8_t u8;
 142                         uint16_t u16;
 143                         int16_t s16;
 144                         uint32_t u32;
 145                         int32_t s32;
 146                         uint64_t u64;
 147                         int64_t s64;
 148                         double d64;
 149                         const char *string;
 150                         int i;
 151                 } basic;
 152
 153                 r = sd_bus_message_peek_type(m, &type, &contents);
 154                 if (r < 0) {
 155                         log_error("Failed to peek type: %s", strerror(-r));
 156                         return r;
 157                 }
 158
 159                 if (r == 0) {
 160                         if (level <= 1)
 161                                 break;
 162
 163                         r = sd_bus_message_exit_container(m);
 164                         if (r < 0) {
 165                                 log_error("Failed to exit container: %s", strerror(-r));
 166                                 return r;
 167                         }
 168
 169                         level--;
 170
 171                         prefix = indent(level, flags);
 172                         if (!prefix)
 173                                 return log_oom();
 174
 175                         fprintf(f, "%s};\n", prefix);
 176                         continue;
 177                 }
 178
 179                 prefix = indent(level, flags);
 180                 if (!prefix)
 181                         return log_oom();
 182
 183                 if (bus_type_is_container(type) > 0) {
 184                         r = sd_bus_message_enter_container(m, type, contents);
 185                         if (r < 0) {
 186                                 log_error("Failed to enter container: %s", strerror(-r));
 187                                 return r;
 188                         }
 189
 190                         if (type == SD_BUS_TYPE_ARRAY)
 191                                 fprintf(f, "%sARRAY \"%s\" {\n", prefix, contents);
 192                         else if (type == SD_BUS_TYPE_VARIANT)
 193                                 fprintf(f, "%sVARIANT \"%s\" {\n", prefix, contents);
 194                         else if (type == SD_BUS_TYPE_STRUCT)
 195                                 fprintf(f, "%sSTRUCT \"%s\" {\n", prefix, contents);
 196                         else if (type == SD_BUS_TYPE_DICT_ENTRY)
 197                                 fprintf(f, "%sDICT_ENTRY \"%s\" {\n", prefix, contents);
 198
 199                         level ++;
 200
 201                         continue;
 202                 }
 203
 204                 r = sd_bus_message_read_basic(m, type, &basic);
 205                 if (r < 0) {
 206                         log_error("Failed to get basic: %s", strerror(-r));
 207                         return r;
 208                 }
 209
 210                 assert(r > 0);
 211
 212                 switch (type) {
 213
 214                 case SD_BUS_TYPE_BYTE:
 215                         fprintf(f, "%sBYTE %s%u%s;\n", prefix, ansi_highlight(), basic.u8, ansi_highlight_off());
 216                         break;
 217
 218                 case SD_BUS_TYPE_BOOLEAN:
 219                         fprintf(f, "%sBOOLEAN %s%s%s;\n", prefix, ansi_highlight(), true_false(basic.i), ansi_highlight_off());
 220                         break;
 221
 222                 case SD_BUS_TYPE_INT16:
 223                         fprintf(f, "%sINT16 %s%i%s;\n", prefix, ansi_highlight(), basic.s16, ansi_highlight_off());
 224                         break;
 225
 226                 case SD_BUS_TYPE_UINT16:
 227                         fprintf(f, "%sUINT16 %s%u%s;\n", prefix, ansi_highlight(), basic.u16, ansi_highlight_off());
 228                         break;
 229
 230                 case SD_BUS_TYPE_INT32:
 231                         fprintf(f, "%sINT32 %s%i%s;\n", prefix, ansi_highlight(), basic.s32, ansi_highlight_off());
 232                         break;
 233
 234                 case SD_BUS_TYPE_UINT32:
 235                         fprintf(f, "%sUINT32 %s%u%s;\n", prefix, ansi_highlight(), basic.u32, ansi_highlight_off());
 236                         break;
 237
 238                 case SD_BUS_TYPE_INT64:
 239                         fprintf(f, "%sINT64 %s%"PRIi64"%s;\n", prefix, ansi_highlight(), basic.s64, ansi_highlight_off());
 240                         break;
 241
 242                 case SD_BUS_TYPE_UINT64:
 243                         fprintf(f, "%sUINT64 %s%"PRIu64"%s;\n", prefix, ansi_highlight(), basic.u64, ansi_highlight_off());
 244                         break;
 245
 246                 case SD_BUS_TYPE_DOUBLE:
 247                         fprintf(f, "%sDOUBLE %s%g%s;\n", prefix, ansi_highlight(), basic.d64, ansi_highlight_off());
 248                         break;
 249
 250                 case SD_BUS_TYPE_STRING:
 251                         fprintf(f, "%sSTRING \"%s%s%s\";\n", prefix, ansi_highlight(), basic.string, ansi_highlight_off());
 252                         break;
 253
 254                 case SD_BUS_TYPE_OBJECT_PATH:
 255                         fprintf(f, "%sOBJECT_PATH \"%s%s%s\";\n", prefix, ansi_highlight(), basic.string, ansi_highlight_off());
 256                         break;
 257
 258                 case SD_BUS_TYPE_SIGNATURE:
 259                         fprintf(f, "%sSIGNATURE \"%s%s%s\";\n", prefix, ansi_highlight(), basic.string, ansi_highlight_off());
 260                         break;
 261
 262                 case SD_BUS_TYPE_UNIX_FD:
 263                         fprintf(f, "%sUNIX_FD %s%i%s;\n", prefix, ansi_highlight(), basic.i, ansi_highlight_off());
 264                         break;
 265
 266                 default:
 267                         assert_not_reached("Unknown basic type.");
 268                 }
 269         }
 270
 271         if (!(flags & BUS_MESSAGE_DUMP_SUBTREE_ONLY))
 272                 fprintf(f, "%s};\n\n", indent(0, flags));
 273
 274         return 0;
 275 }
 276
 277 static void dump_capabilities(
 278                 sd_bus_creds *c,
 279                 FILE *f,
 280                 const char *name,
 281                 bool terse,
 282                 int (*has)(sd_bus_creds *c, int capability)) {
 283
 284         unsigned long i, last_cap;
 285         unsigned n = 0;
 286         int r;
 287
 288         assert(c);
 289         assert(f);
 290         assert(name);
 291         assert(has);
 292
 293         i = 0;
 294         r = has(c, i);
 295         if (r < 0)
 296                 return;
 297
 298         fprintf(f, "%s%s=%s", terse ? "  " : "", name, terse ? "" : ansi_highlight());
 299         last_cap = cap_last_cap();
 300
 301         for (;;) {
 302                 if (r > 0) {
 303                         _cleanup_cap_free_charp_ char *t;
 304
 305                         if (n > 0)
 306                                 fputc(' ', f);
 307                         if (n % 4 == 3)
 308                                 fprintf(f, terse ? "\n          " : "\n        ");
 309
 310                         t = cap_to_name(i);
 311                         fprintf(f, "%s", t);
 312                         n++;
 313                 }
 314
 315                 i++;
 316
 317                 if (i > last_cap)
 318                         break;
 319
 320                 r = has(c, i);
 321         }
 322
 323         fputs("\n", f);
 324
 325         if (!terse)
 326                 fputs(ansi_highlight_off(), f);
 327 }
 328
 329 int bus_creds_dump(sd_bus_creds *c, FILE *f, bool terse) {
 330         bool audit_sessionid_is_set = false, audit_loginuid_is_set = false;
 331         const char *u = NULL, *uu = NULL, *s = NULL, *sl = NULL;
 332         uid_t owner, audit_loginuid;
 333         uint32_t audit_sessionid;
 334         char **cmdline = NULL, **well_known = NULL;
 335         const char *prefix, *color, *suffix;
 336         int r;
 337
 338         assert(c);
 339
 340         if (!f)
 341                 f = stdout;
 342
 343         if (terse) {
 344                 prefix = "  ";
 345                 suffix = "";
 346                 color = "";
 347         } else {
 348                 const char *off;
 349
 350                 prefix = "";
 351                 color = ansi_highlight();
 352
 353                 off = ansi_highlight_off();
 354                 suffix = strappenda(off, "\n");
 355         }
 356
 357         if (c->mask & SD_BUS_CREDS_PID)
 358                 fprintf(f, "%sPID=%s"PID_FMT"%s", prefix, color, c->pid, suffix);
 359         if (c->mask & SD_BUS_CREDS_PID_STARTTIME)
 360                 fprintf(f, "%sPIDStartTime=%s"USEC_FMT"%s", prefix, color, c->pid_starttime, suffix);
 361         if (c->mask & SD_BUS_CREDS_TID)
 362                 fprintf(f, "%sTID=%s"PID_FMT"%s", prefix, color, c->tid, suffix);
 363
 364         if (terse && ((c->mask & (SD_BUS_CREDS_PID|SD_BUS_CREDS_PID_STARTTIME|SD_BUS_CREDS_TID))))
 365                 fputs("\n", f);
 366
 367         if (c->mask & SD_BUS_CREDS_UID)
 368                 fprintf(f, "%sUID=%s"UID_FMT"%s", prefix, color, c->uid, suffix);
 369         if (c->mask & SD_BUS_CREDS_EUID)
 370                 fprintf(f, "%sEUID=%s"UID_FMT"%s", prefix, color, c->euid, suffix);
 371         if (c->mask & SD_BUS_CREDS_SUID)
 372                 fprintf(f, "%sSUID=%s"UID_FMT"%s", prefix, color, c->suid, suffix);
 373         if (c->mask & SD_BUS_CREDS_FSUID)
 374                 fprintf(f, "%sFSUID=%s"UID_FMT"%s", prefix, color, c->fsuid, suffix);
 375         r = sd_bus_creds_get_owner_uid(c, &owner);
 376         if (r >= 0)
 377                 fprintf(f, "%sOwnerUID=%s"UID_FMT"%s", prefix, color, owner, suffix);
 378         if (c->mask & SD_BUS_CREDS_GID)
 379                 fprintf(f, "%sGID=%s"GID_FMT"%s", prefix, color, c->gid, suffix);
 380         if (c->mask & SD_BUS_CREDS_EGID)
 381                 fprintf(f, "%sEGID=%s"GID_FMT"%s", prefix, color, c->egid, suffix);
 382         if (c->mask & SD_BUS_CREDS_SGID)
 383                 fprintf(f, "%sSGID=%s"GID_FMT"%s", prefix, color, c->sgid, suffix);
 384         if (c->mask & SD_BUS_CREDS_FSGID)
 385                 fprintf(f, "%sFSGID=%s"GID_FMT"%s", prefix, color, c->fsgid, suffix);
 386
 387         if (terse && ((c->mask & (SD_BUS_CREDS_UID|SD_BUS_CREDS_EUID|SD_BUS_CREDS_SUID|SD_BUS_CREDS_FSUID|
 388                                   SD_BUS_CREDS_GID|SD_BUS_CREDS_EGID|SD_BUS_CREDS_SGID|SD_BUS_CREDS_FSGID)) || r >= 0))
 389                 fputs("\n", f);
 390
 391         if (c->mask & SD_BUS_CREDS_COMM)
 392                 fprintf(f, "%sComm=%s%s%s", prefix, color, c->comm, suffix);
 393         if (c->mask & SD_BUS_CREDS_TID_COMM)
 394                 fprintf(f, "%sTIDComm=%s%s%s", prefix, color, c->tid_comm, suffix);
 395         if (c->mask & SD_BUS_CREDS_EXE)
 396                 fprintf(f, "%sExe=%s%s%s", prefix, color, c->exe, suffix);
 397
 398         if (terse && (c->mask & (SD_BUS_CREDS_EXE|SD_BUS_CREDS_COMM|SD_BUS_CREDS_TID_COMM)))
 399                 fputs("\n", f);
 400
 401         if (sd_bus_creds_get_cmdline(c, &cmdline) >= 0) {
 402                 char **i;
 403
 404                 fprintf(f, "%sCommandLine=%s", prefix, color);
 405                 STRV_FOREACH(i, cmdline) {
 406                         if (i != cmdline)
 407                                 fputc(' ', f);
 408
 409                         fputs(*i, f);
 410                 }
 411
 412                 fprintf(f, "%s", suffix);
 413         }
 414
 415         if (c->mask & SD_BUS_CREDS_SELINUX_CONTEXT)
 416                 fprintf(f, "%sLabel=%s%s%s", prefix, color, c->label, suffix);
 417         if (c->mask & SD_BUS_CREDS_DESCRIPTION)
 418                 fprintf(f, "%sDescription=%s%s%s", prefix, color, c->description, suffix);
 419
 420         if (terse && (c->mask & (SD_BUS_CREDS_SELINUX_CONTEXT|SD_BUS_CREDS_DESCRIPTION)))
 421                 fputs("\n", f);
 422
 423         if (c->mask & SD_BUS_CREDS_CGROUP)
 424                 fprintf(f, "%sCGroup=%s%s%s", prefix, color, c->cgroup, suffix);
 425         sd_bus_creds_get_unit(c, &u);
 426         if (u)
 427                 fprintf(f, "%sUnit=%s%s%s", prefix, color, u, suffix);
 428         sd_bus_creds_get_user_unit(c, &uu);
 429         if (uu)
 430                 fprintf(f, "%sUserUnit=%s%s%s", prefix, color, uu, suffix);
 431         sd_bus_creds_get_slice(c, &sl);
 432         if (sl)
 433                 fprintf(f, "%sSlice=%s%s%s", prefix, color, sl, suffix);
 434         sd_bus_creds_get_session(c, &s);
 435         if (s)
 436                 fprintf(f, "%sSession=%s%s%s", prefix, color, s, suffix);
 437
 438         if (terse && ((c->mask & SD_BUS_CREDS_CGROUP) || u || uu || sl || s))
 439                 fputs("\n", f);
 440
 441         if (sd_bus_creds_get_audit_login_uid(c, &audit_loginuid) >= 0) {
 442                 audit_loginuid_is_set = true;
 443                 fprintf(f, "%sAuditLoginUID=%s"UID_FMT"%s", prefix, color, audit_loginuid, suffix);
 444         }
 445         if (sd_bus_creds_get_audit_session_id(c, &audit_sessionid) >= 0) {
 446                 audit_sessionid_is_set = true;
 447                 fprintf(f, "%sAuditSessionID=%s%"PRIu32"%s", prefix, color, audit_sessionid, suffix);
 448         }
 449
 450         if (terse && (audit_loginuid_is_set || audit_sessionid_is_set))
 451                 fputs("\n", f);
 452
 453         if (c->mask & SD_BUS_CREDS_UNIQUE_NAME)
 454                 fprintf(f, "%sUniqueName=%s%s%s", prefix, color, c->unique_name, suffix);
 455
 456         if (sd_bus_creds_get_well_known_names(c, &well_known) >= 0) {
 457                 char **i;
 458
 459                 fprintf(f, "%sWellKnownNames=%s", prefix, color);
 460                 STRV_FOREACH(i, well_known) {
 461                         if (i != well_known)
 462                                 fputc(' ', f);
 463
 464                         fputs(*i, f);
 465                 }
 466
 467                 fprintf(f, "%s", suffix);
 468         }
 469
 470         if (terse && (c->mask & SD_BUS_CREDS_UNIQUE_NAME || well_known))
 471                 fputc('\n', f);
 472
 473         dump_capabilities(c, f, "EffectiveCapabilities", terse, sd_bus_creds_has_effective_cap);
 474         dump_capabilities(c, f, "PermittedCapabilities", terse, sd_bus_creds_has_permitted_cap);
 475         dump_capabilities(c, f, "InheritableCapabilities", terse, sd_bus_creds_has_inheritable_cap);
 476         dump_capabilities(c, f, "BoundingCapabilities", terse, sd_bus_creds_has_bounding_cap);
 477
 478         return 0;
 479 }
 480
 481 /*
 482  * For details about the file format, see:
 483  *
 484  * http://wiki.wireshark.org/Development/LibpcapFileFormat
 485  */
 486
 487 typedef struct _packed_ pcap_hdr_s {
 488         uint32_t magic_number;   /* magic number */
 489         uint16_t version_major;  /* major version number */
 490         uint16_t version_minor;  /* minor version number */
 491         int32_t  thiszone;       /* GMT to local correction */
 492         uint32_t sigfigs;        /* accuracy of timestamps */
 493         uint32_t snaplen;        /* max length of captured packets, in octets */
 494         uint32_t network;        /* data link type */
 495 } pcap_hdr_t ;
 496
 497 typedef struct  _packed_ pcaprec_hdr_s {
 498         uint32_t ts_sec;         /* timestamp seconds */
 499         uint32_t ts_usec;        /* timestamp microseconds */
 500         uint32_t incl_len;       /* number of octets of packet saved in file */
 501         uint32_t orig_len;       /* actual length of packet */
 502 } pcaprec_hdr_t;
 503
 504 int bus_pcap_header(size_t snaplen, FILE *f) {
 505
 506         pcap_hdr_t hdr = {
 507                 .magic_number = 0xa1b2c3d4U,
 508                 .version_major = 2,
 509                 .version_minor = 4,
 510                 .thiszone = 0, /* UTC */
 511                 .sigfigs = 0,
 512                 .network = 231, /* D-Bus */
 513         };
 514
 515         if (!f)
 516                 f = stdout;
 517
 518         assert(snaplen > 0);
 519         assert((size_t) (uint32_t) snaplen == snaplen);
 520
 521         hdr.snaplen = (uint32_t) snaplen;
 522
 523         fwrite(&hdr, 1, sizeof(hdr), f);
 524         fflush(f);
 525
 526         return 0;
 527 }
 528
 529 int bus_message_pcap_frame(sd_bus_message *m, size_t snaplen, FILE *f) {
 530         struct bus_body_part *part;
 531         pcaprec_hdr_t hdr = {};
 532         struct timeval tv;
 533         unsigned i;
 534         size_t w;
 535
 536         if (!f)
 537                 f = stdout;
 538
 539         assert(m);
 540         assert(snaplen > 0);
 541         assert((size_t) (uint32_t) snaplen == snaplen);
 542
 543         if (m->realtime != 0)
 544                 timeval_store(&tv, m->realtime);
 545         else
 546                 assert_se(gettimeofday(&tv, NULL) >= 0);
 547
 548         hdr.ts_sec = tv.tv_sec;
 549         hdr.ts_usec = tv.tv_usec;
 550         hdr.orig_len = BUS_MESSAGE_SIZE(m);
 551         hdr.incl_len = MIN(hdr.orig_len, snaplen);
 552
 553         /* write the pcap header */
 554         fwrite(&hdr, 1, sizeof(hdr), f);
 555
 556         /* write the dbus header */
 557         w = MIN(BUS_MESSAGE_BODY_BEGIN(m), snaplen);
 558         fwrite(m->header, 1, w, f);
 559         snaplen -= w;
 560
 561         /* write the dbus body */
 562         MESSAGE_FOREACH_PART(part, i, m) {
 563                 if (snaplen <= 0)
 564                         break;
 565
 566                 w = MIN(part->size, snaplen);
 567                 fwrite(part->data, 1, w, f);
 568                 snaplen -= w;
 569         }
 570
 571         fflush(f);
 572
 573         return 0;
 574 }