util/log.c

   1 /*
   2  * Logging support
   3  *
   4  *  Copyright (c) 2003 Fabrice Bellard
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include "qemu/osdep.h"
  21 #include "qemu/log.h"
  22 #include "qemu/range.h"
  23 #include "qemu/error-report.h"
  24 #include "qapi/error.h"
  25 #include "qemu/cutils.h"
  26 #include "trace/control.h"
  27 #include "qemu/thread.h"
  28 #include "qemu/lockable.h"
  29 #include "qemu/rcu.h"
  30 #ifdef CONFIG_LINUX
  31 #include <sys/syscall.h>
  32 #endif
  33
  34
  35 typedef struct RCUCloseFILE {
  36     struct rcu_head rcu;
  37     FILE *fd;
  38 } RCUCloseFILE;
  39
  40 /* Mutex covering the other global_* variables. */
  41 static QemuMutex global_mutex;
  42 static char *global_filename;
  43 static FILE *global_file;
  44 static __thread FILE *thread_file;
  45 static __thread Notifier qemu_log_thread_cleanup_notifier;
  46
  47 int qemu_loglevel;
  48 static bool log_per_thread;
  49 static GArray *debug_regions;
  50
  51 /* Returns true if qemu_log() will really write somewhere. */
  52 bool qemu_log_enabled(void)
  53 {
  54     return log_per_thread || qatomic_read(&global_file) != NULL;
  55 }
  56
  57 /* Returns true if qemu_log() will write somewhere other than stderr. */
  58 bool qemu_log_separate(void)
  59 {
  60     if (log_per_thread) {
  61         return true;
  62     } else {
  63         FILE *logfile = qatomic_read(&global_file);
  64         return logfile && logfile != stderr;
  65     }
  66 }
  67
  68 static int log_thread_id(void)
  69 {
  70 #ifdef CONFIG_GETTID
  71     return gettid();
  72 #elif defined(SYS_gettid)
  73     return syscall(SYS_gettid);
  74 #else
  75     static int counter;
  76     return qatomic_fetch_inc(&counter);
  77 #endif
  78 }
  79
  80 static void qemu_log_thread_cleanup(Notifier *n, void *unused)
  81 {
  82     if (thread_file != stderr) {
  83         fclose(thread_file);
  84         thread_file = NULL;
  85     }
  86 }
  87
  88 /* Lock/unlock output. */
  89
  90 static FILE *qemu_log_trylock_with_err(Error **errp)
  91 {
  92     FILE *logfile;
  93
  94     logfile = thread_file;
  95     if (!logfile) {
  96         if (log_per_thread) {
  97             g_autofree char *filename
  98                 = g_strdup_printf(global_filename, log_thread_id());
  99             logfile = fopen(filename, "w");
 100             if (!logfile) {
 101                 error_setg_errno(errp, errno,
 102                                  "Error opening logfile %s for thread %d",
 103                                  filename, log_thread_id());
 104                 return NULL;
 105             }
 106             thread_file = logfile;
 107             qemu_log_thread_cleanup_notifier.notify = qemu_log_thread_cleanup;
 108             qemu_thread_atexit_add(&qemu_log_thread_cleanup_notifier);
 109         } else {
 110             rcu_read_lock();
 111             /*
 112              * FIXME: typeof_strip_qual, as used by qatomic_rcu_read,
 113              * does not work with pointers to undefined structures,
 114              * such as we have with struct _IO_FILE and musl libc.
 115              * Since all we want is a read of a pointer, cast to void**,
 116              * which does work with typeof_strip_qual.
 117              */
 118             logfile = qatomic_rcu_read((void **)&global_file);
 119             if (!logfile) {
 120                 rcu_read_unlock();
 121                 return NULL;
 122             }
 123         }
 124     }
 125
 126     qemu_flockfile(logfile);
 127     return logfile;
 128 }
 129
 130 FILE *qemu_log_trylock(void)
 131 {
 132     return qemu_log_trylock_with_err(NULL);
 133 }
 134
 135 void qemu_log_unlock(FILE *logfile)
 136 {
 137     if (logfile) {
 138         fflush(logfile);
 139         qemu_funlockfile(logfile);
 140         if (!log_per_thread) {
 141             rcu_read_unlock();
 142         }
 143     }
 144 }
 145
 146 void qemu_log(const char *fmt, ...)
 147 {
 148     FILE *f = qemu_log_trylock();
 149     if (f) {
 150         va_list ap;
 151
 152         va_start(ap, fmt);
 153         vfprintf(f, fmt, ap);
 154         va_end(ap);
 155         qemu_log_unlock(f);
 156     }
 157 }
 158
 159 static void __attribute__((__constructor__)) startup(void)
 160 {
 161     qemu_mutex_init(&global_mutex);
 162 }
 163
 164 static void rcu_close_file(RCUCloseFILE *r)
 165 {
 166     fclose(r->fd);
 167     g_free(r);
 168 }
 169
 170 /**
 171  * valid_filename_template:
 172  *
 173  * Validate the filename template.  Require %d if per_thread, allow it
 174  * otherwise; require no other % within the template.
 175  */
 176
 177 typedef enum {
 178     vft_error,
 179     vft_stderr,
 180     vft_strdup,
 181     vft_pid_printf,
 182 } ValidFilenameTemplateResult;
 183
 184 static ValidFilenameTemplateResult
 185 valid_filename_template(const char *filename, bool per_thread, Error **errp)
 186 {
 187     if (filename) {
 188         char *pidstr = strstr(filename, "%");
 189
 190         if (pidstr) {
 191             /* We only accept one %d, no other format strings */
 192             if (pidstr[1] != 'd' || strchr(pidstr + 2, '%')) {
 193                 error_setg(errp, "Bad logfile template: %s", filename);
 194                 return 0;
 195             }
 196             return per_thread ? vft_strdup : vft_pid_printf;
 197         }
 198     }
 199     if (per_thread) {
 200         error_setg(errp, "Filename template with '%%d' required for 'tid'");
 201         return vft_error;
 202     }
 203     return filename ? vft_strdup : vft_stderr;
 204 }
 205
 206 /* enable or disable low levels log */
 207 static bool qemu_set_log_internal(const char *filename, bool changed_name,
 208                                   int log_flags, Error **errp)
 209 {
 210     bool need_to_open_file;
 211     bool daemonized;
 212     bool per_thread;
 213     FILE *logfile;
 214
 215     QEMU_LOCK_GUARD(&global_mutex);
 216     logfile = global_file;
 217
 218     /* The per-thread flag is immutable. */
 219     if (log_per_thread) {
 220         log_flags |= LOG_PER_THREAD;
 221     } else {
 222         if (global_filename) {
 223             log_flags &= ~LOG_PER_THREAD;
 224         }
 225     }
 226
 227     per_thread = log_flags & LOG_PER_THREAD;
 228
 229     if (changed_name) {
 230         char *newname = NULL;
 231
 232         /*
 233          * Once threads start opening their own log files, we have no
 234          * easy mechanism to tell them all to close and re-open.
 235          * There seems little cause to do so either -- this option
 236          * will most often be used at user-only startup.
 237          */
 238         if (log_per_thread) {
 239             error_setg(errp, "Cannot change log filename after setting 'tid'");
 240             return false;
 241         }
 242
 243         switch (valid_filename_template(filename, per_thread, errp)) {
 244         case vft_error:
 245             return false;
 246         case vft_stderr:
 247             break;
 248         case vft_strdup:
 249             newname = g_strdup(filename);
 250             break;
 251         case vft_pid_printf:
 252             newname = g_strdup_printf(filename, getpid());
 253             break;
 254         }
 255
 256         g_free(global_filename);
 257         global_filename = newname;
 258         filename = newname;
 259     } else {
 260         filename = global_filename;
 261         if (per_thread &&
 262             valid_filename_template(filename, true, errp) == vft_error) {
 263             return false;
 264         }
 265     }
 266
 267     /* Once the per-thread flag is set, it cannot be unset. */
 268     if (per_thread) {
 269         log_per_thread = true;
 270     }
 271     /* The flag itself is not relevant for need_to_open_file. */
 272     log_flags &= ~LOG_PER_THREAD;
 273 #ifdef CONFIG_TRACE_LOG
 274     log_flags |= LOG_TRACE;
 275 #endif
 276     qemu_loglevel = log_flags;
 277
 278     daemonized = is_daemonized();
 279     need_to_open_file = false;
 280     if (!daemonized) {
 281         /*
 282          * If not daemonized we only log if qemu_loglevel is set, either to
 283          * stderr or to a file (if there is a filename).
 284          * If per-thread, open the file for each thread in qemu_log_trylock().
 285          */
 286         need_to_open_file = qemu_loglevel && !log_per_thread;
 287     } else {
 288         /*
 289          * If we are daemonized, we will only log if there is a filename.
 290          */
 291         need_to_open_file = filename != NULL;
 292     }
 293
 294     if (logfile) {
 295         fflush(logfile);
 296         if (changed_name && logfile != stderr) {
 297             RCUCloseFILE *r = g_new0(RCUCloseFILE, 1);
 298             r->fd = logfile;
 299             qatomic_rcu_set(&global_file, NULL);
 300             call_rcu(r, rcu_close_file, rcu);
 301             logfile = NULL;
 302         }
 303     }
 304
 305     if (log_per_thread && daemonized) {
 306         logfile = thread_file;
 307     }
 308
 309     if (!logfile && need_to_open_file) {
 310         if (filename) {
 311             if (log_per_thread) {
 312                 logfile = qemu_log_trylock_with_err(errp);
 313                 if (!logfile) {
 314                     return false;
 315                 }
 316                 qemu_log_unlock(logfile);
 317             } else {
 318                 logfile = fopen(filename, "w");
 319                 if (!logfile) {
 320                     error_setg_errno(errp, errno, "Error opening logfile %s",
 321                                      filename);
 322                     return false;
 323                 }
 324             }
 325             /* In case we are a daemon redirect stderr to logfile */
 326             if (daemonized) {
 327                 dup2(fileno(logfile), STDERR_FILENO);
 328                 fclose(logfile);
 329                 /*
 330                  * This will skip closing logfile in rcu_close_file()
 331                  * or qemu_log_thread_cleanup().
 332                  */
 333                 logfile = stderr;
 334             }
 335         } else {
 336             /* Default to stderr if no log file specified */
 337             assert(!daemonized);
 338             logfile = stderr;
 339         }
 340
 341         if (log_per_thread && daemonized) {
 342             thread_file = logfile;
 343         } else {
 344             qatomic_rcu_set(&global_file, logfile);
 345         }
 346     }
 347     return true;
 348 }
 349
 350 bool qemu_set_log(int log_flags, Error **errp)
 351 {
 352     return qemu_set_log_internal(NULL, false, log_flags, errp);
 353 }
 354
 355 bool qemu_set_log_filename(const char *filename, Error **errp)
 356 {
 357     return qemu_set_log_internal(filename, true, qemu_loglevel, errp);
 358 }
 359
 360 bool qemu_set_log_filename_flags(const char *name, int flags, Error **errp)
 361 {
 362     return qemu_set_log_internal(name, true, flags, errp);
 363 }
 364
 365 /* Returns true if addr is in our debug filter or no filter defined
 366  */
 367 bool qemu_log_in_addr_range(uint64_t addr)
 368 {
 369     if (debug_regions) {
 370         int i = 0;
 371         for (i = 0; i < debug_regions->len; i++) {
 372             Range *range = &g_array_index(debug_regions, Range, i);
 373             if (range_contains(range, addr)) {
 374                 return true;
 375             }
 376         }
 377         return false;
 378     } else {
 379         return true;
 380     }
 381 }
 382
 383
 384 void qemu_set_dfilter_ranges(const char *filter_spec, Error **errp)
 385 {
 386     gchar **ranges = g_strsplit(filter_spec, ",", 0);
 387     int i;
 388
 389     if (debug_regions) {
 390         g_array_unref(debug_regions);
 391         debug_regions = NULL;
 392     }
 393
 394     debug_regions = g_array_sized_new(FALSE, FALSE,
 395                                       sizeof(Range), g_strv_length(ranges));
 396     for (i = 0; ranges[i]; i++) {
 397         const char *r = ranges[i];
 398         const char *range_op, *r2, *e;
 399         uint64_t r1val, r2val, lob, upb;
 400         struct Range range;
 401
 402         range_op = strstr(r, "-");
 403         r2 = range_op ? range_op + 1 : NULL;
 404         if (!range_op) {
 405             range_op = strstr(r, "+");
 406             r2 = range_op ? range_op + 1 : NULL;
 407         }
 408         if (!range_op) {
 409             range_op = strstr(r, "..");
 410             r2 = range_op ? range_op + 2 : NULL;
 411         }
 412         if (!range_op) {
 413             error_setg(errp, "Bad range specifier");
 414             goto out;
 415         }
 416
 417         if (qemu_strtou64(r, &e, 0, &r1val)
 418             || e != range_op) {
 419             error_setg(errp, "Invalid number to the left of %.*s",
 420                        (int)(r2 - range_op), range_op);
 421             goto out;
 422         }
 423         if (qemu_strtou64(r2, NULL, 0, &r2val)) {
 424             error_setg(errp, "Invalid number to the right of %.*s",
 425                        (int)(r2 - range_op), range_op);
 426             goto out;
 427         }
 428
 429         switch (*range_op) {
 430         case '+':
 431             lob = r1val;
 432             upb = r1val + r2val - 1;
 433             break;
 434         case '-':
 435             upb = r1val;
 436             lob = r1val - (r2val - 1);
 437             break;
 438         case '.':
 439             lob = r1val;
 440             upb = r2val;
 441             break;
 442         default:
 443             g_assert_not_reached();
 444         }
 445         if (lob > upb) {
 446             error_setg(errp, "Invalid range");
 447             goto out;
 448         }
 449         range_set_bounds(&range, lob, upb);
 450         g_array_append_val(debug_regions, range);
 451     }
 452 out:
 453     g_strfreev(ranges);
 454 }
 455
 456 const QEMULogItem qemu_log_items[] = {
 457     { CPU_LOG_TB_OUT_ASM, "out_asm",
 458       "show generated host assembly code for each compiled TB" },
 459     { CPU_LOG_TB_IN_ASM, "in_asm",
 460       "show target assembly code for each compiled TB" },
 461     { CPU_LOG_TB_OP, "op",
 462       "show micro ops for each compiled TB" },
 463     { CPU_LOG_TB_OP_OPT, "op_opt",
 464       "show micro ops after optimization" },
 465     { CPU_LOG_TB_OP_IND, "op_ind",
 466       "show micro ops before indirect lowering" },
 467     { CPU_LOG_INT, "int",
 468       "show interrupts/exceptions in short format" },
 469     { CPU_LOG_EXEC, "exec",
 470       "show trace before each executed TB (lots of logs)" },
 471     { CPU_LOG_TB_CPU, "cpu",
 472       "show CPU registers before entering a TB (lots of logs)" },
 473     { CPU_LOG_TB_FPU, "fpu",
 474       "include FPU registers in the 'cpu' logging" },
 475     { CPU_LOG_MMU, "mmu",
 476       "log MMU-related activities" },
 477     { CPU_LOG_PCALL, "pcall",
 478       "x86 only: show protected mode far calls/returns/exceptions" },
 479     { CPU_LOG_RESET, "cpu_reset",
 480       "show CPU state before CPU resets" },
 481     { LOG_UNIMP, "unimp",
 482       "log unimplemented functionality" },
 483     { LOG_GUEST_ERROR, "guest_errors",
 484       "log when the guest OS does something invalid (eg accessing a\n"
 485       "non-existent register)" },
 486     { CPU_LOG_PAGE, "page",
 487       "dump pages at beginning of user mode emulation" },
 488     { CPU_LOG_TB_NOCHAIN, "nochain",
 489       "do not chain compiled TBs so that \"exec\" and \"cpu\" show\n"
 490       "complete traces" },
 491 #ifdef CONFIG_PLUGIN
 492     { CPU_LOG_PLUGIN, "plugin", "output from TCG plugins\n"},
 493 #endif
 494     { LOG_STRACE, "strace",
 495       "log every user-mode syscall, its input, and its result" },
 496     { LOG_PER_THREAD, "tid",
 497       "open a separate log file per thread; filename must contain '%d'" },
 498     { 0, NULL, NULL },
 499 };
 500
 501 /* takes a comma separated list of log masks. Return 0 if error. */
 502 int qemu_str_to_log_mask(const char *str)
 503 {
 504     const QEMULogItem *item;
 505     int mask = 0;
 506     char **parts = g_strsplit(str, ",", 0);
 507     char **tmp;
 508
 509     for (tmp = parts; tmp && *tmp; tmp++) {
 510         if (g_str_equal(*tmp, "all")) {
 511             for (item = qemu_log_items; item->mask != 0; item++) {
 512                 mask |= item->mask;
 513             }
 514 #ifdef CONFIG_TRACE_LOG
 515         } else if (g_str_has_prefix(*tmp, "trace:") && (*tmp)[6] != '\0') {
 516             trace_enable_events((*tmp) + 6);
 517             mask |= LOG_TRACE;
 518 #endif
 519         } else {
 520             for (item = qemu_log_items; item->mask != 0; item++) {
 521                 if (g_str_equal(*tmp, item->name)) {
 522                     goto found;
 523                 }
 524             }
 525             goto error;
 526         found:
 527             mask |= item->mask;
 528         }
 529     }
 530
 531     g_strfreev(parts);
 532     return mask;
 533
 534  error:
 535     g_strfreev(parts);
 536     return 0;
 537 }
 538
 539 void qemu_print_log_usage(FILE *f)
 540 {
 541     const QEMULogItem *item;
 542     fprintf(f, "Log items (comma separated):\n");
 543     for (item = qemu_log_items; item->mask != 0; item++) {
 544         fprintf(f, "%-15s %s\n", item->name, item->help);
 545     }
 546 #ifdef CONFIG_TRACE_LOG
 547     fprintf(f, "trace:PATTERN   enable trace events\n");
 548     fprintf(f, "\nUse \"-d trace:help\" to get a list of trace events.\n\n");
 549 #endif
 550 }