output.c

   1 /*
   2  * This file is part of ltrace.
   3  * Copyright (C) 2011,2012,2013 Petr Machata, Red Hat Inc.
   4  * Copyright (C) 2010 Joe Damato
   5  * Copyright (C) 1997,1998,1999,2001,2002,2003,2004,2007,2008,2009 Juan Cespedes
   6  * Copyright (C) 2006 Paul Gilliam, IBM Corporation
   7  * Copyright (C) 2006 Ian Wienand
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License as
  11  * published by the Free Software Foundation; either version 2 of the
  12  * License, or (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful, but
  15  * WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  22  * 02110-1301 USA
  23  */
  24
  25 #include "config.h"
  26
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <stdarg.h>
  30 #include <string.h>
  31 #include <time.h>
  32 #include <sys/time.h>
  33 #include <unistd.h>
  34 #include <errno.h>
  35 #include <assert.h>
  36
  37 #include "output.h"
  38 #include "demangle.h"
  39 #include "fetch.h"
  40 #include "lens_default.h"
  41 #include "library.h"
  42 #include "memstream.h"
  43 #include "options.h"
  44 #include "param.h"
  45 #include "proc.h"
  46 #include "prototype.h"
  47 #include "summary.h"
  48 #include "type.h"
  49 #include "value.h"
  50 #include "value_dict.h"
  51
  52 static struct process *current_proc = NULL;
  53 static size_t current_depth = 0;
  54 static int current_column = 0;
  55
  56 static void
  57 output_indent(struct process *proc)
  58 {
  59         int d = options.indent * (proc->callstack_depth - 1);
  60         current_column += fprintf(options.output, "%*s", d, "");
  61 }
  62
  63 static void
  64 begin_of_line(struct process *proc, int is_func, int indent)
  65 {
  66         current_column = 0;
  67         if (!proc) {
  68                 return;
  69         }
  70         if ((options.output != stderr) && (opt_p || options.follow)) {
  71                 current_column += fprintf(options.output, "%u ", proc->pid);
  72         } else if (options.follow) {
  73                 current_column += fprintf(options.output, "[pid %u] ", proc->pid);
  74         }
  75         if (opt_r) {
  76                 struct timeval tv;
  77                 static struct timeval old_tv = { 0, 0 };
  78                 struct timeval diff;
  79
  80                 gettimeofday(&tv, NULL);
  81
  82                 if (old_tv.tv_sec == 0 && old_tv.tv_usec == 0) {
  83                         old_tv.tv_sec = tv.tv_sec;
  84                         old_tv.tv_usec = tv.tv_usec;
  85                 }
  86                 diff.tv_sec = tv.tv_sec - old_tv.tv_sec;
  87                 if (tv.tv_usec >= old_tv.tv_usec) {
  88                         diff.tv_usec = tv.tv_usec - old_tv.tv_usec;
  89                 } else {
  90                         diff.tv_sec--;
  91                         diff.tv_usec = 1000000 + tv.tv_usec - old_tv.tv_usec;
  92                 }
  93                 old_tv.tv_sec = tv.tv_sec;
  94                 old_tv.tv_usec = tv.tv_usec;
  95                 current_column += fprintf(options.output, "%3lu.%06d ",
  96                                           (unsigned long)diff.tv_sec,
  97                                           (int)diff.tv_usec);
  98         }
  99         if (opt_t) {
 100                 struct timeval tv;
 101                 gettimeofday(&tv, NULL);
 102                 if (opt_t > 2) {
 103                         current_column += fprintf(options.output, "%lu.%06d ",
 104                                                   (unsigned long)tv.tv_sec,
 105                                                   (int)tv.tv_usec);
 106                 } else if (opt_t > 1) {
 107                         struct tm *tmp = localtime(&tv.tv_sec);
 108                         current_column +=
 109                             fprintf(options.output, "%02d:%02d:%02d.%06d ",
 110                                     tmp->tm_hour, tmp->tm_min, tmp->tm_sec,
 111                                     (int)tv.tv_usec);
 112                 } else {
 113                         struct tm *tmp = localtime(&tv.tv_sec);
 114                         current_column += fprintf(options.output, "%02d:%02d:%02d ",
 115                                                   tmp->tm_hour, tmp->tm_min,
 116                                                   tmp->tm_sec);
 117                 }
 118         }
 119         if (opt_i) {
 120                 if (is_func) {
 121                         struct callstack_element *stel
 122                                 = &proc->callstack[proc->callstack_depth - 1];
 123                         current_column += fprintf(options.output, "[%p] ",
 124                                                   stel->return_addr);
 125                 } else {
 126                         current_column += fprintf(options.output, "[%p] ",
 127                                                   proc->instruction_pointer);
 128                 }
 129         }
 130         if (options.indent > 0 && indent) {
 131                 output_indent(proc);
 132         }
 133 }
 134
 135 static struct arg_type_info *
 136 get_unknown_type(void)
 137 {
 138         static struct arg_type_info *ret = NULL;
 139         if (ret != NULL)
 140                 return ret;
 141
 142         static struct arg_type_info info;
 143         info = *type_get_simple(ARGTYPE_LONG);
 144         info.lens = &guess_lens;
 145         ret = &info;
 146         return ret;
 147 }
 148
 149 /* The default prototype is: long X(long, long, long, long).  */
 150 static struct prototype *
 151 build_default_prototype(void)
 152 {
 153         static struct prototype *ret = NULL;
 154         if (ret != NULL)
 155                 return ret;
 156
 157         static struct prototype proto;
 158         prototype_init(&proto);
 159
 160         struct arg_type_info *unknown_type = get_unknown_type();
 161         assert(unknown_type != NULL);
 162         proto.return_info = unknown_type;
 163         proto.own_return_info = 0;
 164
 165         struct param unknown_param;
 166         param_init_type(&unknown_param, unknown_type, 0);
 167
 168         size_t i;
 169         for (i = 0; i < 4; ++i)
 170                 if (prototype_push_param(&proto, &unknown_param) < 0) {
 171                         report_global_error("build_default_prototype: %s",
 172                                             strerror(errno));
 173                         prototype_destroy(&proto);
 174                         return NULL;
 175                 }
 176
 177         ret = &proto;
 178         return ret;
 179 }
 180
 181 static bool
 182 snip_period(char *buf)
 183 {
 184         char *period = strrchr(buf, '.');
 185         if (period != NULL && strcmp(period, ".so") != 0) {
 186                 *period = 0;
 187                 return true;
 188         } else {
 189                 return false;
 190         }
 191 }
 192
 193 static struct prototype *
 194 library_get_prototype(struct library *lib, const char *name)
 195 {
 196         if (lib->protolib == NULL) {
 197                 size_t sz = strlen(lib->soname);
 198                 char buf[sz + 1];
 199                 memcpy(buf, lib->soname, sz + 1);
 200
 201                 do {
 202                         if (protolib_cache_maybe_load(&g_protocache, buf, 0,
 203                                                       true, &lib->protolib) < 0)
 204                                 return NULL;
 205                 } while (lib->protolib == NULL
 206                          && lib->type == LT_LIBTYPE_DSO
 207                          && snip_period(buf));
 208
 209                 if (lib->protolib == NULL)
 210                         lib->protolib = protolib_cache_default(&g_protocache,
 211                                                                buf, 0);
 212         }
 213         if (lib->protolib == NULL)
 214                 return NULL;
 215
 216         return protolib_lookup_prototype(lib->protolib, name,
 217                                          lib->type != LT_LIBTYPE_SYSCALL);
 218 }
 219
 220 struct find_proto_data {
 221         const char *name;
 222         struct prototype *ret;
 223 };
 224
 225 static enum callback_status
 226 find_proto_cb(struct process *proc, struct library *lib, void *d)
 227 {
 228         struct find_proto_data *data = d;
 229         data->ret = library_get_prototype(lib, data->name);
 230         return CBS_STOP_IF(data->ret != NULL);
 231 }
 232
 233 static struct prototype *
 234 lookup_symbol_prototype(struct process *proc, struct library_symbol *libsym)
 235 {
 236         if (libsym->proto != NULL)
 237                 return libsym->proto;
 238
 239         struct library *lib = libsym->lib;
 240         if (lib != NULL) {
 241                 struct find_proto_data data = { libsym->name };
 242                 data.ret = library_get_prototype(lib, libsym->name);
 243                 if (data.ret == NULL
 244                     && libsym->plt_type == LS_TOPLT_EXEC)
 245                         proc_each_library(proc, NULL, find_proto_cb, &data);
 246                 if (data.ret != NULL)
 247                         return data.ret;
 248         }
 249
 250         return build_default_prototype();
 251 }
 252
 253 void
 254 output_line(struct process *proc, const char *fmt, ...)
 255 {
 256         if (options.summary)
 257                 return;
 258
 259         if (current_proc != NULL) {
 260                 if (current_proc->callstack[current_depth].return_addr)
 261                         fprintf(options.output, " <unfinished ...>\n");
 262                 else
 263                         fprintf(options.output, " <no return ...>\n");
 264         }
 265         current_proc = NULL;
 266         if (fmt == NULL)
 267                 return;
 268
 269         begin_of_line(proc, 0, 0);
 270
 271         va_list args;
 272         va_start(args, fmt);
 273         vfprintf(options.output, fmt, args);
 274         fprintf(options.output, "\n");
 275         va_end(args);
 276
 277         current_column = 0;
 278 }
 279
 280 static void
 281 tabto(int col) {
 282         if (current_column < col) {
 283                 fprintf(options.output, "%*s", col - current_column, "");
 284         }
 285 }
 286
 287 static int
 288 output_error(FILE *stream)
 289 {
 290         return fprintf(stream, "?");
 291 }
 292
 293 static int
 294 fetch_simple_param(enum tof type, struct process *proc,
 295                    struct fetch_context *context,
 296                    struct value_dict *arguments,
 297                    struct arg_type_info *info, int own,
 298                    struct value *valuep)
 299 {
 300         /* Arrays decay into pointers per C standard.  We check for
 301          * this here, because here we also capture arrays that come
 302          * from parameter packs.  */
 303         if (info->type == ARGTYPE_ARRAY) {
 304                 struct arg_type_info *tmp = malloc(sizeof(*tmp));
 305                 if (tmp != NULL) {
 306                         type_init_pointer(tmp, info, own);
 307                         tmp->lens = info->lens;
 308                         info = tmp;
 309                         own = 1;
 310                 }
 311         }
 312
 313         struct value value;
 314         value_init(&value, proc, NULL, info, own);
 315         if (fetch_arg_next(context, type, proc, info, &value) < 0)
 316                 return -1;
 317
 318         if (val_dict_push_next(arguments, &value) < 0) {
 319                 value_destroy(&value);
 320                 return -1;
 321         }
 322
 323         if (valuep != NULL)
 324                 *valuep = value;
 325
 326         return 0;
 327 }
 328
 329 static void
 330 fetch_param_stop(struct value_dict *arguments, ssize_t *params_leftp)
 331 {
 332         if (*params_leftp == -1)
 333                 *params_leftp = val_dict_count(arguments);
 334 }
 335
 336 static int
 337 fetch_param_pack(enum tof type, struct process *proc,
 338                  struct fetch_context *context,
 339                  struct value_dict *arguments, struct param *param,
 340                  ssize_t *params_leftp)
 341 {
 342         struct param_enum *e = param_pack_init(param, arguments);
 343         if (e == NULL)
 344                 return -1;
 345
 346         int ret = 0;
 347         while (1) {
 348                 int insert_stop = 0;
 349                 struct arg_type_info *info = malloc(sizeof(*info));
 350                 if (info == NULL
 351                     || param_pack_next(param, e, info, &insert_stop) < 0) {
 352                 fail:
 353                         free(info);
 354                         ret = -1;
 355                         break;
 356                 }
 357
 358                 if (insert_stop)
 359                         fetch_param_stop(arguments, params_leftp);
 360
 361                 if (info->type == ARGTYPE_VOID) {
 362                         type_destroy(info);
 363                         free(info);
 364                         break;
 365                 }
 366
 367                 struct value val;
 368                 if (fetch_simple_param(type, proc, context, arguments,
 369                                        info, 1, &val) < 0)
 370                         goto fail;
 371
 372                 int stop = 0;
 373                 switch (param_pack_stop(param, e, &val)) {
 374                 case PPCB_ERR:
 375                         goto fail;
 376                 case PPCB_STOP:
 377                         stop = 1;
 378                 case PPCB_CONT:
 379                         break;
 380                 }
 381
 382                 if (stop)
 383                         break;
 384         }
 385
 386         param_pack_done(param, e);
 387         return ret;
 388 }
 389
 390 static int
 391 fetch_one_param(enum tof type, struct process *proc,
 392                 struct fetch_context *context,
 393                 struct value_dict *arguments, struct param *param,
 394                 ssize_t *params_leftp)
 395 {
 396         switch (param->flavor) {
 397                 int rc;
 398         case PARAM_FLAVOR_TYPE:
 399                 return fetch_simple_param(type, proc, context, arguments,
 400                                           param->u.type.type, 0, NULL);
 401
 402         case PARAM_FLAVOR_PACK:
 403                 if (fetch_param_pack_start(context,
 404                                            param->u.pack.ppflavor) < 0)
 405                         return -1;
 406                 rc = fetch_param_pack(type, proc, context, arguments,
 407                                       param, params_leftp);
 408                 fetch_param_pack_end(context);
 409                 return rc;
 410
 411         case PARAM_FLAVOR_STOP:
 412                 fetch_param_stop(arguments, params_leftp);
 413                 return 0;
 414         }
 415
 416         assert(!"Invalid param flavor!");
 417         abort();
 418 }
 419
 420 struct fetch_one_param_data
 421 {
 422         struct process *proc;
 423         struct fetch_context *context;
 424         struct value_dict *arguments;
 425         ssize_t *params_leftp;
 426         enum tof tof;
 427 };
 428
 429 static enum callback_status
 430 fetch_one_param_cb(struct prototype *proto, struct param *param, void *data)
 431 {
 432         struct fetch_one_param_data *cb_data = data;
 433         return CBS_STOP_IF(fetch_one_param(cb_data->tof, cb_data->proc,
 434                                            cb_data->context,
 435                                            cb_data->arguments, param,
 436                                            cb_data->params_leftp) < 0);
 437 }
 438
 439 static int
 440 fetch_params(enum tof type, struct process *proc,
 441              struct fetch_context *context,
 442              struct value_dict *arguments, struct prototype *func,
 443              ssize_t *params_leftp)
 444 {
 445         struct fetch_one_param_data cb_data
 446                 = { proc, context, arguments, params_leftp, type };
 447         if (prototype_each_param(func, NULL,
 448                                  &fetch_one_param_cb, &cb_data) != NULL)
 449                 return -1;
 450
 451         /* Implicit stop at the end of parameter list.  */
 452         fetch_param_stop(arguments, params_leftp);
 453
 454         return 0;
 455 }
 456
 457 struct format_argument_data
 458 {
 459         struct value *value;
 460         struct value_dict *arguments;
 461 };
 462
 463 static int
 464 format_argument_cb(FILE *stream, void *ptr)
 465 {
 466         struct format_argument_data *data = ptr;
 467         int o = format_argument(stream, data->value, data->arguments);
 468         if (o < 0)
 469                 o = output_error(stream);
 470         return o;
 471 }
 472
 473 static int
 474 output_params(struct value_dict *arguments, size_t start, size_t end,
 475               int *need_delimp)
 476 {
 477         size_t i;
 478         for (i = start; i < end; ++i) {
 479                 struct value *value = val_dict_get_num(arguments, i);
 480                 if (value == NULL)
 481                         return -1;
 482
 483                 struct format_argument_data data = { value, arguments };
 484                 int o = delim_output(options.output, need_delimp,
 485                                      format_argument_cb, &data);
 486                 if (o < 0)
 487                         return -1;
 488                 current_column += o;
 489         }
 490         return 0;
 491 }
 492
 493 void
 494 output_left(enum tof type, struct process *proc,
 495             struct library_symbol *libsym)
 496 {
 497         assert(! options.summary);
 498
 499         if (current_proc) {
 500                 fprintf(options.output, " <unfinished ...>\n");
 501                 current_column = 0;
 502         }
 503         current_proc = proc;
 504         current_depth = proc->callstack_depth;
 505         begin_of_line(proc, type == LT_TOF_FUNCTION, 1);
 506         if (!options.hide_caller && libsym->lib != NULL
 507             && libsym->plt_type != LS_TOPLT_NONE)
 508                 /* We don't terribly mind failing this.  */
 509                 account_output(&current_column,
 510                                fprintf(options.output, "%s->",
 511                                        libsym->lib->soname));
 512
 513         const char *name = libsym->name;
 514 #ifdef USE_DEMANGLE
 515         if (options.demangle)
 516                 name = my_demangle(libsym->name);
 517 #endif
 518         if (account_output(&current_column,
 519                            fprintf(options.output, "%s", name)) < 0)
 520                 return;
 521
 522         if (libsym->lib != NULL
 523             && libsym->lib->type != LT_LIBTYPE_MAIN
 524             && libsym->plt_type == LS_TOPLT_NONE
 525             && account_output(&current_column,
 526                               fprintf(options.output, "@%s",
 527                                       libsym->lib->soname)) < 0)
 528                 /* We do mind failing this though.  */
 529                 return;
 530
 531         account_output(&current_column, fprintf(options.output, "("));
 532
 533         struct prototype *func = lookup_symbol_prototype(proc, libsym);
 534         if (func == NULL) {
 535         fail:
 536                 account_output(&current_column, fprintf(options.output, "???"));
 537                 return;
 538         }
 539
 540         struct fetch_context *context = fetch_arg_init(type, proc,
 541                                                        func->return_info);
 542         if (context == NULL)
 543                 goto fail;
 544
 545         struct value_dict *arguments = malloc(sizeof(*arguments));
 546         if (arguments == NULL) {
 547                 fetch_arg_done(context);
 548                 goto fail;
 549         }
 550         val_dict_init(arguments);
 551
 552         ssize_t params_left = -1;
 553         int need_delim = 0;
 554         if (fetch_params(type, proc, context, arguments, func, &params_left) < 0
 555             || output_params(arguments, 0, params_left, &need_delim) < 0) {
 556                 val_dict_destroy(arguments);
 557                 fetch_arg_done(context);
 558                 arguments = NULL;
 559                 context = NULL;
 560         }
 561
 562         struct callstack_element *stel
 563                 = &proc->callstack[proc->callstack_depth - 1];
 564         stel->fetch_context = context;
 565         stel->arguments = arguments;
 566         stel->out.params_left = params_left;
 567         stel->out.need_delim = need_delim;
 568 }
 569
 570 void
 571 output_right(enum tof type, struct process *proc, struct library_symbol *libsym,
 572              struct timedelta *spent)
 573 {
 574         assert(! options.summary);
 575
 576         struct prototype *func = lookup_symbol_prototype(proc, libsym);
 577         if (func == NULL)
 578                 return;
 579
 580         if (current_proc != NULL
 581                     && (current_proc != proc
 582                         || current_depth != proc->callstack_depth)) {
 583                 fprintf(options.output, " <unfinished ...>\n");
 584                 current_proc = NULL;
 585         }
 586         if (current_proc != proc) {
 587                 begin_of_line(proc, type == LT_TOF_FUNCTIONR, 1);
 588 #ifdef USE_DEMANGLE
 589                 current_column +=
 590                     fprintf(options.output, "<... %s resumed> ",
 591                             options.demangle ? my_demangle(libsym->name)
 592                             : libsym->name);
 593 #else
 594                 current_column +=
 595                     fprintf(options.output, "<... %s resumed> ", libsym->name);
 596 #endif
 597         }
 598
 599         struct callstack_element *stel
 600                 = &proc->callstack[proc->callstack_depth - 1];
 601
 602         struct fetch_context *context = stel->fetch_context;
 603
 604         /* Fetch & enter into dictionary the retval first, so that
 605          * other values can use it in expressions.  */
 606         struct value retval;
 607         int own_retval = 0;
 608         if (context != NULL) {
 609                 value_init(&retval, proc, NULL, func->return_info, 0);
 610                 own_retval = 1;
 611                 if (fetch_retval(context, type, proc, func->return_info,
 612                                  &retval) < 0)
 613                         value_set_type(&retval, NULL, 0);
 614                 else if (stel->arguments != NULL
 615                            && val_dict_push_named(stel->arguments, &retval,
 616                                                   "retval", 0) == 0)
 617                         own_retval = 0;
 618         }
 619
 620         if (stel->arguments != NULL)
 621                 output_params(stel->arguments, stel->out.params_left,
 622                               val_dict_count(stel->arguments),
 623                               &stel->out.need_delim);
 624
 625         current_column += fprintf(options.output, ") ");
 626         tabto(options.align - 1);
 627         fprintf(options.output, "= ");
 628
 629         if (context != NULL && retval.type != NULL) {
 630                 struct format_argument_data data = { &retval, stel->arguments };
 631                 format_argument_cb(options.output, &data);
 632         }
 633
 634         if (own_retval)
 635                 value_destroy(&retval);
 636
 637         if (opt_T) {
 638                 assert(spent != NULL);
 639                 fprintf(options.output, " <%lu.%06d>",
 640                         (unsigned long) spent->tm.tv_sec,
 641                         (int) spent->tm.tv_usec);
 642         }
 643
 644         fprintf(options.output, "\n");
 645
 646 #if defined(HAVE_LIBUNWIND)
 647         if (options.bt_depth > 0
 648             && proc->unwind_priv != NULL
 649             && proc->unwind_as != NULL) {
 650                 unw_cursor_t cursor;
 651                 arch_addr_t ip, function_offset;
 652                 struct library *lib = NULL;
 653                 int unwind_depth = options.bt_depth;
 654                 char fn_name[100];
 655                 const char *lib_name;
 656                 size_t distance;
 657
 658                 /* Verify that we can safely cast arch_addr_t* to
 659                  * unw_word_t*.  */
 660                 (void)sizeof(char[1 - 2*(sizeof(unw_word_t)
 661                                         != sizeof(arch_addr_t))]);
 662                 unw_init_remote(&cursor, proc->unwind_as, proc->unwind_priv);
 663                 while (unwind_depth) {
 664
 665                         if (unw_get_reg(&cursor, UNW_REG_IP, (unw_word_t *) &ip)) {
 666                                 fprintf(options.output, " > stacktrace_error\n");
 667                                 continue;
 668                         }
 669
 670                         /* We are looking for the library with the base address
 671                          * closest to the current ip.  */
 672                         lib_name = "unmapped_area";
 673                         distance = (size_t) -1;
 674                         lib = proc->libraries;
 675                         while (lib != NULL) {
 676                                 /* N.B.: Assumes sizeof(size_t) ==
 677                                  * sizeof(arch_addr_t).
 678                                  * Keyword: double cast.  */
 679                                 if ((ip >= lib->base) &&
 680                                             ((size_t)(ip - lib->base)
 681                                             < distance)) {
 682                                         distance = ip - lib->base;
 683                                         lib_name = lib->pathname;
 684                                 }
 685                                 lib = lib->next;
 686                         }
 687
 688                         own_retval = unw_get_proc_name(&cursor, fn_name, sizeof(fn_name),
 689                                                 (unw_word_t *) &function_offset);
 690                         if ((own_retval == 0) || (own_retval == -UNW_ENOMEM))
 691                                 fprintf(options.output, " > %s(%s+%p) [%p]\n",
 692                                         lib_name, fn_name, function_offset, ip);
 693                         else
 694                                 fprintf(options.output, " > %s(??\?) [%p]\n",
 695                                         lib_name, ip);
 696
 697                         if (unw_step(&cursor) <= 0)
 698                                 break;
 699                         unwind_depth--;
 700                 }
 701                 fprintf(options.output, "\n");
 702         }
 703 #endif /* defined(HAVE_LIBUNWIND) */
 704
 705         current_proc = NULL;
 706         current_column = 0;
 707 }
 708
 709 int
 710 delim_output(FILE *stream, int *need_delimp,
 711              int (*writer)(FILE *stream, void *data),
 712              void *data)
 713 {
 714         int o;
 715
 716         /* If we don't need a delimiter, then we don't need to go
 717          * through a temporary stream.  It's all the same whether
 718          * WRITER emits anything or not.  */
 719         if (!*need_delimp) {
 720                 o = writer(stream, data);
 721
 722         } else {
 723                 struct memstream ms;
 724                 if (memstream_init(&ms) < 0)
 725                         return -1;
 726                 o = writer(ms.stream, data);
 727                 if (memstream_close(&ms) < 0)
 728                         o = -1;
 729                 if (o > 0 && ((*need_delimp
 730                                && account_output(&o, fprintf(stream, ", ")) < 0)
 731                               || fwrite(ms.buf, 1, ms.size, stream) != ms.size))
 732                         o = -1;
 733
 734                 memstream_destroy(&ms);
 735         }
 736
 737         if (o < 0)
 738                 return -1;
 739
 740         *need_delimp = *need_delimp || o > 0;
 741         return o;
 742 }
 743
 744 int
 745 account_output(int *countp, int c)
 746 {
 747         if (c > 0)
 748                 *countp += c;
 749         return c;
 750 }
 751
 752 static void
 753 do_report(const char *filename, unsigned line_no, const char *severity,
 754           const char *fmt, va_list args)
 755 {
 756         char buf[128];
 757         vsnprintf(buf, sizeof(buf), fmt, args);
 758         buf[sizeof(buf) - 1] = 0;
 759         if (filename != NULL)
 760                 output_line(0, "%s:%d: %s: %s",
 761                             filename, line_no, severity, buf);
 762         else
 763                 output_line(0, "%s: %s", severity, buf);
 764 }
 765
 766 void
 767 report_error(const char *filename, unsigned line_no, const char *fmt, ...)
 768 {
 769         va_list args;
 770         va_start(args, fmt);
 771         do_report(filename, line_no, "error", fmt, args);
 772         va_end(args);
 773 }
 774
 775 void
 776 report_warning(const char *filename, unsigned line_no, const char *fmt, ...)
 777 {
 778         va_list args;
 779         va_start(args, fmt);
 780         do_report(filename, line_no, "warning", fmt, args);
 781         va_end(args);
 782 }
 783
 784 void
 785 report_global_error(const char *fmt, ...)
 786 {
 787         va_list args;
 788         va_start(args, fmt);
 789         do_report(NULL, 0, "error", fmt, args);
 790         va_end(args);
 791 }