lib/libpmc/pmclog.c

   1 /*-
   2  * Copyright (c) 2005-2007 Joseph Koshy
   3  * Copyright (c) 2007 The FreeBSD Foundation
   4  * All rights reserved.
   5  *
   6  * Portions of this software were developed by A. Joseph Koshy under
   7  * sponsorship from the FreeBSD Foundation and Google, Inc.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28  * SUCH DAMAGE.
  29  */
  30
  31 #include <sys/cdefs.h>
  32 __FBSDID("$FreeBSD$");
  33
  34 #include <sys/param.h>
  35 #include <sys/pmc.h>
  36 #include <sys/pmclog.h>
  37
  38 #include <assert.h>
  39 #include <errno.h>
  40 #include <pmc.h>
  41 #include <pmclog.h>
  42 #include <stddef.h>
  43 #include <stdlib.h>
  44 #include <string.h>
  45 #include <strings.h>
  46 #include <unistd.h>
  47
  48 #include <machine/pmc_mdep.h>
  49
  50 #include "libpmcinternal.h"
  51
  52 #define PMCLOG_BUFFER_SIZE                      4096
  53
  54 /*
  55  * API NOTES
  56  *
  57  * The pmclog(3) API is oriented towards parsing an event stream in
  58  * "realtime", i.e., from an data source that may or may not preserve
  59  * record boundaries -- for example when the data source is elsewhere
  60  * on a network.  The API allows data to be fed into the parser zero
  61  * or more bytes at a time.
  62  *
  63  * The state for a log file parser is maintained in a 'struct
  64  * pmclog_parse_state'.  Parser invocations are done by calling
  65  * 'pmclog_read()'; this function will inform the caller when a
  66  * complete event is parsed.
  67  *
  68  * The parser first assembles a complete log file event in an internal
  69  * work area (see "ps_saved" below).  Once a complete log file event
  70  * is read, the parser then parses it and converts it to an event
  71  * descriptor usable by the client.  We could possibly avoid this two
  72  * step process by directly parsing the input log to set fields in the
  73  * event record.  However the parser's state machine would get
  74  * insanely complicated, and this code is unlikely to be used in
  75  * performance critical paths.
  76  */
  77
  78 enum pmclog_parser_state {
  79         PL_STATE_NEW_RECORD,            /* in-between records */
  80         PL_STATE_EXPECTING_HEADER,      /* header being read */
  81         PL_STATE_PARTIAL_RECORD,        /* header present but not the record */
  82         PL_STATE_ERROR                  /* parsing error encountered */
  83 };
  84
  85 struct pmclog_parse_state {
  86         enum pmclog_parser_state ps_state;
  87         enum pmc_cputype        ps_arch;        /* log file architecture */
  88         uint32_t                ps_version;     /* hwpmc version */
  89         int                     ps_initialized; /* whether initialized */
  90         int                     ps_count;       /* count of records processed */
  91         off_t                   ps_offset;      /* stream byte offset */
  92         union pmclog_entry      ps_saved;       /* saved partial log entry */
  93         int                     ps_svcount;     /* #bytes saved */
  94         int                     ps_fd;          /* active fd or -1 */
  95         char                    *ps_buffer;     /* scratch buffer if fd != -1 */
  96         char                    *ps_data;       /* current parse pointer */
  97         size_t                  ps_len;         /* length of buffered data */
  98 };
  99
 100 #define PMCLOG_HEADER_FROM_SAVED_STATE(PS)                              \
 101         (* ((uint32_t *) &(PS)->ps_saved))
 102
 103 #define PMCLOG_INITIALIZE_READER(LE,A)  LE = (uint32_t *) &(A)
 104 #define PMCLOG_READ32(LE,V)             do {                            \
 105                 (V)  = *(LE)++;                                         \
 106         } while (0)
 107 #define PMCLOG_READ64(LE,V)             do {                            \
 108                 uint64_t _v;                                            \
 109                 _v  = (uint64_t) *(LE)++;                               \
 110                 _v |= ((uint64_t) *(LE)++) << 32;                       \
 111                 (V) = _v;                                               \
 112         } while (0)
 113
 114 #define PMCLOG_READSTRING(LE,DST,LEN)   strlcpy((DST), (char *) (LE), (LEN))
 115
 116 /*
 117  * Assemble a log record from '*len' octets starting from address '*data'.
 118  * Update 'data' and 'len' to reflect the number of bytes consumed.
 119  *
 120  * '*data' is potentially an unaligned address and '*len' octets may
 121  * not be enough to complete a event record.
 122  */
 123
 124 static enum pmclog_parser_state
 125 pmclog_get_record(struct pmclog_parse_state *ps, char **data, ssize_t *len)
 126 {
 127         int avail, copylen, recordsize, used;
 128         uint32_t h;
 129         const int HEADERSIZE = sizeof(uint32_t);
 130         char *src, *dst;
 131
 132         if ((avail = *len) <= 0)
 133                 return (ps->ps_state = PL_STATE_ERROR);
 134
 135         src = *data;
 136         h = used = 0;
 137
 138         if (ps->ps_state == PL_STATE_NEW_RECORD)
 139                 ps->ps_svcount = 0;
 140
 141         dst = (char *) &ps->ps_saved + ps->ps_svcount;
 142
 143         switch (ps->ps_state) {
 144         case PL_STATE_NEW_RECORD:
 145
 146                 /*
 147                  * Transitions:
 148                  *
 149                  * Case A: avail < headersize
 150                  *      -> 'expecting header'
 151                  *
 152                  * Case B: avail >= headersize
 153                  *    B.1: avail < recordsize
 154                  *         -> 'partial record'
 155                  *    B.2: avail >= recordsize
 156                  *         -> 'new record'
 157                  */
 158
 159                 copylen = avail < HEADERSIZE ? avail : HEADERSIZE;
 160                 bcopy(src, dst, copylen);
 161                 ps->ps_svcount = used = copylen;
 162
 163                 if (copylen < HEADERSIZE) {
 164                         ps->ps_state = PL_STATE_EXPECTING_HEADER;
 165                         goto done;
 166                 }
 167
 168                 src += copylen;
 169                 dst += copylen;
 170
 171                 h = PMCLOG_HEADER_FROM_SAVED_STATE(ps);
 172                 recordsize = PMCLOG_HEADER_TO_LENGTH(h);
 173
 174                 if (recordsize <= 0)
 175                         goto error;
 176
 177                 if (recordsize <= avail) { /* full record available */
 178                         bcopy(src, dst, recordsize - copylen);
 179                         ps->ps_svcount = used = recordsize;
 180                         goto done;
 181                 }
 182
 183                 /* header + a partial record is available */
 184                 bcopy(src, dst, avail - copylen);
 185                 ps->ps_svcount = used = avail;
 186                 ps->ps_state = PL_STATE_PARTIAL_RECORD;
 187
 188                 break;
 189
 190         case PL_STATE_EXPECTING_HEADER:
 191
 192                 /*
 193                  * Transitions:
 194                  *
 195                  * Case C: avail+saved < headersize
 196                  *      -> 'expecting header'
 197                  *
 198                  * Case D: avail+saved >= headersize
 199                  *    D.1: avail+saved < recordsize
 200                  *      -> 'partial record'
 201                  *    D.2: avail+saved >= recordsize
 202                  *      -> 'new record'
 203                  *    (see PARTIAL_RECORD handling below)
 204                  */
 205
 206                 if (avail + ps->ps_svcount < HEADERSIZE) {
 207                         bcopy(src, dst, avail);
 208                         ps->ps_svcount += avail;
 209                         used = avail;
 210                         break;
 211                 }
 212
 213                 used = copylen = HEADERSIZE - ps->ps_svcount;
 214                 bcopy(src, dst, copylen);
 215                 src += copylen;
 216                 dst += copylen;
 217                 avail -= copylen;
 218                 ps->ps_svcount += copylen;
 219
 220                 /*FALLTHROUGH*/
 221
 222         case PL_STATE_PARTIAL_RECORD:
 223
 224                 /*
 225                  * Transitions:
 226                  *
 227                  * Case E: avail+saved < recordsize
 228                  *      -> 'partial record'
 229                  *
 230                  * Case F: avail+saved >= recordsize
 231                  *      -> 'new record'
 232                  */
 233
 234                 h = PMCLOG_HEADER_FROM_SAVED_STATE(ps);
 235                 recordsize = PMCLOG_HEADER_TO_LENGTH(h);
 236
 237                 if (recordsize <= 0)
 238                         goto error;
 239
 240                 if (avail + ps->ps_svcount < recordsize) {
 241                         copylen = avail;
 242                         ps->ps_state = PL_STATE_PARTIAL_RECORD;
 243                 } else {
 244                         copylen = recordsize - ps->ps_svcount;
 245                         ps->ps_state = PL_STATE_NEW_RECORD;
 246                 }
 247
 248                 bcopy(src, dst, copylen);
 249                 ps->ps_svcount += copylen;
 250                 used += copylen;
 251                 break;
 252
 253         default:
 254                 goto error;
 255         }
 256
 257  done:
 258         *data += used;
 259         *len  -= used;
 260         return ps->ps_state;
 261
 262  error:
 263         ps->ps_state = PL_STATE_ERROR;
 264         return ps->ps_state;
 265 }
 266
 267 /*
 268  * Get an event from the stream pointed to by '*data'.  '*len'
 269  * indicates the number of bytes available to parse.  Arguments
 270  * '*data' and '*len' are updated to indicate the number of bytes
 271  * consumed.
 272  */
 273
 274 static int
 275 pmclog_get_event(void *cookie, char **data, ssize_t *len,
 276     struct pmclog_ev *ev)
 277 {
 278         int evlen, pathlen;
 279         uint32_t h, *le, npc;
 280         enum pmclog_parser_state e;
 281         struct pmclog_parse_state *ps;
 282
 283         ps = (struct pmclog_parse_state *) cookie;
 284
 285         assert(ps->ps_state != PL_STATE_ERROR);
 286
 287         if ((e = pmclog_get_record(ps,data,len)) == PL_STATE_ERROR) {
 288                 ev->pl_state = PMCLOG_ERROR;
 289                 return -1;
 290         }
 291
 292         if (e != PL_STATE_NEW_RECORD) {
 293                 ev->pl_state = PMCLOG_REQUIRE_DATA;
 294                 return -1;
 295         }
 296
 297         PMCLOG_INITIALIZE_READER(le, ps->ps_saved);
 298
 299         PMCLOG_READ32(le,h);
 300
 301         if (!PMCLOG_HEADER_CHECK_MAGIC(h)) {
 302                 ps->ps_state = PL_STATE_ERROR;
 303                 ev->pl_state = PMCLOG_ERROR;
 304                 return -1;
 305         }
 306
 307         /* copy out the time stamp */
 308         PMCLOG_READ32(le,ev->pl_ts.tv_sec);
 309         PMCLOG_READ32(le,ev->pl_ts.tv_nsec);
 310
 311         evlen = PMCLOG_HEADER_TO_LENGTH(h);
 312
 313 #define PMCLOG_GET_PATHLEN(P,E,TYPE) do {                               \
 314                 (P) = (E) - offsetof(struct TYPE, pl_pathname);         \
 315                 if ((P) > PATH_MAX || (P) < 0)                          \
 316                         goto error;                                     \
 317         } while (0)
 318
 319 #define PMCLOG_GET_CALLCHAIN_SIZE(SZ,E) do {                            \
 320                 (SZ) = ((E) - offsetof(struct pmclog_callchain, pl_pc)) \
 321                         / sizeof(uintfptr_t);                           \
 322         } while (0);
 323
 324         switch (ev->pl_type = PMCLOG_HEADER_TO_TYPE(h)) {
 325         case PMCLOG_TYPE_CALLCHAIN:
 326                 PMCLOG_READ32(le,ev->pl_u.pl_cc.pl_pid);
 327                 PMCLOG_READ32(le,ev->pl_u.pl_cc.pl_pmcid);
 328                 PMCLOG_READ32(le,ev->pl_u.pl_cc.pl_cpuflags);
 329                 PMCLOG_GET_CALLCHAIN_SIZE(ev->pl_u.pl_cc.pl_npc,evlen);
 330                 for (npc = 0; npc < ev->pl_u.pl_cc.pl_npc; npc++)
 331                         PMCLOG_READADDR(le,ev->pl_u.pl_cc.pl_pc[npc]);
 332                 for (;npc < PMC_CALLCHAIN_DEPTH_MAX; npc++)
 333                         ev->pl_u.pl_cc.pl_pc[npc] = (uintfptr_t) 0;
 334                 break;
 335         case PMCLOG_TYPE_CLOSELOG:
 336         case PMCLOG_TYPE_DROPNOTIFY:
 337                 /* nothing to do */
 338                 break;
 339         case PMCLOG_TYPE_INITIALIZE:
 340                 PMCLOG_READ32(le,ev->pl_u.pl_i.pl_version);
 341                 PMCLOG_READ32(le,ev->pl_u.pl_i.pl_arch);
 342                 ps->ps_version = ev->pl_u.pl_i.pl_version;
 343                 ps->ps_arch = ev->pl_u.pl_i.pl_arch;
 344                 ps->ps_initialized = 1;
 345                 break;
 346         case PMCLOG_TYPE_MAP_IN:
 347                 PMCLOG_GET_PATHLEN(pathlen,evlen,pmclog_map_in);
 348                 PMCLOG_READ32(le,ev->pl_u.pl_mi.pl_pid);
 349                 PMCLOG_READADDR(le,ev->pl_u.pl_mi.pl_start);
 350                 PMCLOG_READSTRING(le, ev->pl_u.pl_mi.pl_pathname, pathlen);
 351                 break;
 352         case PMCLOG_TYPE_MAP_OUT:
 353                 PMCLOG_READ32(le,ev->pl_u.pl_mo.pl_pid);
 354                 PMCLOG_READADDR(le,ev->pl_u.pl_mo.pl_start);
 355                 PMCLOG_READADDR(le,ev->pl_u.pl_mo.pl_end);
 356                 break;
 357         case PMCLOG_TYPE_PCSAMPLE:
 358                 PMCLOG_READ32(le,ev->pl_u.pl_s.pl_pid);
 359                 PMCLOG_READADDR(le,ev->pl_u.pl_s.pl_pc);
 360                 PMCLOG_READ32(le,ev->pl_u.pl_s.pl_pmcid);
 361                 PMCLOG_READ32(le,ev->pl_u.pl_s.pl_usermode);
 362                 break;
 363         case PMCLOG_TYPE_PMCALLOCATE:
 364                 PMCLOG_READ32(le,ev->pl_u.pl_a.pl_pmcid);
 365                 PMCLOG_READ32(le,ev->pl_u.pl_a.pl_event);
 366                 PMCLOG_READ32(le,ev->pl_u.pl_a.pl_flags);
 367                 if ((ev->pl_u.pl_a.pl_evname =
 368                     _pmc_name_of_event(ev->pl_u.pl_a.pl_event, ps->ps_arch))
 369                     == NULL)
 370                         goto error;
 371                 break;
 372         case PMCLOG_TYPE_PMCATTACH:
 373                 PMCLOG_GET_PATHLEN(pathlen,evlen,pmclog_pmcattach);
 374                 PMCLOG_READ32(le,ev->pl_u.pl_t.pl_pmcid);
 375                 PMCLOG_READ32(le,ev->pl_u.pl_t.pl_pid);
 376                 PMCLOG_READSTRING(le,ev->pl_u.pl_t.pl_pathname,pathlen);
 377                 break;
 378         case PMCLOG_TYPE_PMCDETACH:
 379                 PMCLOG_READ32(le,ev->pl_u.pl_d.pl_pmcid);
 380                 PMCLOG_READ32(le,ev->pl_u.pl_d.pl_pid);
 381                 break;
 382         case PMCLOG_TYPE_PROCCSW:
 383                 PMCLOG_READ32(le,ev->pl_u.pl_c.pl_pmcid);
 384                 PMCLOG_READ64(le,ev->pl_u.pl_c.pl_value);
 385                 PMCLOG_READ32(le,ev->pl_u.pl_c.pl_pid);
 386                 break;
 387         case PMCLOG_TYPE_PROCEXEC:
 388                 PMCLOG_GET_PATHLEN(pathlen,evlen,pmclog_procexec);
 389                 PMCLOG_READ32(le,ev->pl_u.pl_x.pl_pid);
 390                 PMCLOG_READADDR(le,ev->pl_u.pl_x.pl_entryaddr);
 391                 PMCLOG_READ32(le,ev->pl_u.pl_x.pl_pmcid);
 392                 PMCLOG_READSTRING(le,ev->pl_u.pl_x.pl_pathname,pathlen);
 393                 break;
 394         case PMCLOG_TYPE_PROCEXIT:
 395                 PMCLOG_READ32(le,ev->pl_u.pl_e.pl_pmcid);
 396                 PMCLOG_READ64(le,ev->pl_u.pl_e.pl_value);
 397                 PMCLOG_READ32(le,ev->pl_u.pl_e.pl_pid);
 398                 break;
 399         case PMCLOG_TYPE_PROCFORK:
 400                 PMCLOG_READ32(le,ev->pl_u.pl_f.pl_oldpid);
 401                 PMCLOG_READ32(le,ev->pl_u.pl_f.pl_newpid);
 402                 break;
 403         case PMCLOG_TYPE_SYSEXIT:
 404                 PMCLOG_READ32(le,ev->pl_u.pl_se.pl_pid);
 405                 break;
 406         case PMCLOG_TYPE_USERDATA:
 407                 PMCLOG_READ32(le,ev->pl_u.pl_u.pl_userdata);
 408                 break;
 409         default:        /* unknown record type */
 410                 ps->ps_state = PL_STATE_ERROR;
 411                 ev->pl_state = PMCLOG_ERROR;
 412                 return (-1);
 413         }
 414
 415         ev->pl_offset = (ps->ps_offset += evlen);
 416         ev->pl_count  = (ps->ps_count += 1);
 417         ev->pl_state = PMCLOG_OK;
 418         return 0;
 419
 420  error:
 421         ev->pl_state = PMCLOG_ERROR;
 422         ps->ps_state = PL_STATE_ERROR;
 423         return -1;
 424 }
 425
 426 /*
 427  * Extract and return the next event from the byte stream.
 428  *
 429  * Returns 0 and sets the event's state to PMCLOG_OK in case an event
 430  * was successfully parsed.  Otherwise this function returns -1 and
 431  * sets the event's state to one of PMCLOG_REQUIRE_DATA (if more data
 432  * is needed) or PMCLOG_EOF (if an EOF was seen) or PMCLOG_ERROR if
 433  * a parse error was encountered.
 434  */
 435
 436 int
 437 pmclog_read(void *cookie, struct pmclog_ev *ev)
 438 {
 439         int retval;
 440         ssize_t nread;
 441         struct pmclog_parse_state *ps;
 442
 443         ps = (struct pmclog_parse_state *) cookie;
 444
 445         if (ps->ps_state == PL_STATE_ERROR) {
 446                 ev->pl_state = PMCLOG_ERROR;
 447                 return -1;
 448         }
 449
 450         /*
 451          * If there isn't enough data left for a new event try and get
 452          * more data.
 453          */
 454         if (ps->ps_len == 0) {
 455                 ev->pl_state = PMCLOG_REQUIRE_DATA;
 456
 457                 /*
 458                  * If we have a valid file descriptor to read from, attempt
 459                  * to read from that.  This read may return with an error,
 460                  * (which may be EAGAIN or other recoverable error), or
 461                  * can return EOF.
 462                  */
 463                 if (ps->ps_fd != PMCLOG_FD_NONE) {
 464                 refill:
 465                         nread = read(ps->ps_fd, ps->ps_buffer,
 466                             PMCLOG_BUFFER_SIZE);
 467
 468                         if (nread <= 0) {
 469                                 if (nread == 0)
 470                                         ev->pl_state = PMCLOG_EOF;
 471                                 else if (errno != EAGAIN) /* not restartable */
 472                                         ev->pl_state = PMCLOG_ERROR;
 473                                 return -1;
 474                         }
 475
 476                         ps->ps_len = nread;
 477                         ps->ps_data = ps->ps_buffer;
 478                 } else
 479                         return -1;
 480         }
 481
 482         assert(ps->ps_len > 0);
 483
 484
 485          /* Retrieve one event from the byte stream. */
 486         retval = pmclog_get_event(ps, &ps->ps_data, &ps->ps_len, ev);
 487
 488         /*
 489          * If we need more data and we have a configured fd, try read
 490          * from it.
 491          */
 492         if (retval < 0 && ev->pl_state == PMCLOG_REQUIRE_DATA &&
 493             ps->ps_fd != -1) {
 494                 assert(ps->ps_len == 0);
 495                 goto refill;
 496         }
 497
 498         return retval;
 499 }
 500
 501 /*
 502  * Feed data to a memory based parser.
 503  *
 504  * The memory area pointed to by 'data' needs to be valid till the
 505  * next error return from pmclog_next_event().
 506  */
 507
 508 int
 509 pmclog_feed(void *cookie, char *data, int len)
 510 {
 511         struct pmclog_parse_state *ps;
 512
 513         ps = (struct pmclog_parse_state *) cookie;
 514
 515         if (len < 0 ||          /* invalid length */
 516             ps->ps_buffer ||    /* called for a file parser */
 517             ps->ps_len != 0)    /* unnecessary call */
 518                 return -1;
 519
 520         ps->ps_data = data;
 521         ps->ps_len  = len;
 522
 523         return 0;
 524 }
 525
 526 /*
 527  * Allocate and initialize parser state.
 528  */
 529
 530 void *
 531 pmclog_open(int fd)
 532 {
 533         struct pmclog_parse_state *ps;
 534
 535         if ((ps = (struct pmclog_parse_state *) malloc(sizeof(*ps))) == NULL)
 536                 return NULL;
 537
 538         ps->ps_state = PL_STATE_NEW_RECORD;
 539         ps->ps_arch = -1;
 540         ps->ps_initialized = 0;
 541         ps->ps_count = 0;
 542         ps->ps_offset = (off_t) 0;
 543         bzero(&ps->ps_saved, sizeof(ps->ps_saved));
 544         ps->ps_svcount = 0;
 545         ps->ps_fd    = fd;
 546         ps->ps_data  = NULL;
 547         ps->ps_buffer = NULL;
 548         ps->ps_len   = 0;
 549
 550         /* allocate space for a work area */
 551         if (ps->ps_fd != PMCLOG_FD_NONE) {
 552                 if ((ps->ps_buffer = malloc(PMCLOG_BUFFER_SIZE)) == NULL)
 553                         return NULL;
 554         }
 555
 556         return ps;
 557 }
 558
 559
 560 /*
 561  * Free up parser state.
 562  */
 563
 564 void
 565 pmclog_close(void *cookie)
 566 {
 567         struct pmclog_parse_state *ps;
 568
 569         ps = (struct pmclog_parse_state *) cookie;
 570
 571         if (ps->ps_buffer)
 572                 free(ps->ps_buffer);
 573
 574         free(ps);
 575 }