trace.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) 2000-2002 Michael R. Elkins <me@mutt.org>
   5  * Copyright (C) 2002-2004 Oswald Buddenhagen <ossi@users.sf.net>
   6  * Copyright (C) 2004 Theodore Y. Ts'o <tytso@mit.edu>
   7  * Copyright (C) 2006 Mike McCormack
   8  * Copyright (C) 2006 Christian Couder
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; either version 2 of the License, or
  13  *  (at your option) any later version.
  14  *
  15  *  This program is distributed in the hope that it will be useful,
  16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  *  GNU General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License
  21  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  22  */
  23
  24 #include "cache.h"
  25 #include "quote.h"
  26
  27 struct trace_key trace_default_key = { "GIT_TRACE", 0, 0, 0 };
  28 struct trace_key trace_perf_key = TRACE_KEY_INIT(PERFORMANCE);
  29 struct trace_key trace_setup_key = TRACE_KEY_INIT(SETUP);
  30
  31 /* Get a trace file descriptor from "key" env variable. */
  32 static int get_trace_fd(struct trace_key *key)
  33 {
  34         const char *trace;
  35
  36         /* don't open twice */
  37         if (key->initialized)
  38                 return key->fd;
  39
  40         trace = getenv(key->key);
  41
  42         if (!trace || !strcmp(trace, "") ||
  43             !strcmp(trace, "0") || !strcasecmp(trace, "false"))
  44                 key->fd = 0;
  45         else if (!strcmp(trace, "1") || !strcasecmp(trace, "true"))
  46                 key->fd = STDERR_FILENO;
  47         else if (strlen(trace) == 1 && isdigit(*trace))
  48                 key->fd = atoi(trace);
  49         else if (is_absolute_path(trace)) {
  50                 int fd = open(trace, O_WRONLY | O_APPEND | O_CREAT, 0666);
  51                 if (fd == -1) {
  52                         warning("could not open '%s' for tracing: %s",
  53                                 trace, strerror(errno));
  54                         trace_disable(key);
  55                 } else {
  56                         key->fd = fd;
  57                         key->need_close = 1;
  58                 }
  59         } else {
  60                 warning("unknown trace value for '%s': %s\n"
  61                         "         If you want to trace into a file, then please set %s\n"
  62                         "         to an absolute pathname (starting with /)",
  63                         key->key, trace, key->key);
  64                 trace_disable(key);
  65         }
  66
  67         key->initialized = 1;
  68         return key->fd;
  69 }
  70
  71 void trace_disable(struct trace_key *key)
  72 {
  73         if (key->need_close)
  74                 close(key->fd);
  75         key->fd = 0;
  76         key->initialized = 1;
  77         key->need_close = 0;
  78 }
  79
  80 static int prepare_trace_line(const char *file, int line,
  81                               struct trace_key *key, struct strbuf *buf)
  82 {
  83         static struct trace_key trace_bare = TRACE_KEY_INIT(BARE);
  84         struct timeval tv;
  85         struct tm tm;
  86         time_t secs;
  87
  88         if (!trace_want(key))
  89                 return 0;
  90
  91         /* unit tests may want to disable additional trace output */
  92         if (trace_want(&trace_bare))
  93                 return 1;
  94
  95         /* print current timestamp */
  96         gettimeofday(&tv, NULL);
  97         secs = tv.tv_sec;
  98         localtime_r(&secs, &tm);
  99         strbuf_addf(buf, "%02d:%02d:%02d.%06ld ", tm.tm_hour, tm.tm_min,
 100                     tm.tm_sec, (long) tv.tv_usec);
 101
 102 #ifdef HAVE_VARIADIC_MACROS
 103         /* print file:line */
 104         strbuf_addf(buf, "%s:%d ", file, line);
 105         /* align trace output (column 40 catches most files names in git) */
 106         while (buf->len < 40)
 107                 strbuf_addch(buf, ' ');
 108 #endif
 109
 110         return 1;
 111 }
 112
 113 static void trace_write(struct trace_key *key, const void *buf, unsigned len)
 114 {
 115         if (write_in_full(get_trace_fd(key), buf, len) < 0) {
 116                 warning("unable to write trace for %s: %s",
 117                         key->key, strerror(errno));
 118                 trace_disable(key);
 119         }
 120 }
 121
 122 void trace_verbatim(struct trace_key *key, const void *buf, unsigned len)
 123 {
 124         if (!trace_want(key))
 125                 return;
 126         trace_write(key, buf, len);
 127 }
 128
 129 static void print_trace_line(struct trace_key *key, struct strbuf *buf)
 130 {
 131         strbuf_complete_line(buf);
 132         trace_write(key, buf->buf, buf->len);
 133 }
 134
 135 static void trace_vprintf_fl(const char *file, int line, struct trace_key *key,
 136                              const char *format, va_list ap)
 137 {
 138         struct strbuf buf = STRBUF_INIT;
 139
 140         if (!prepare_trace_line(file, line, key, &buf))
 141                 return;
 142
 143         strbuf_vaddf(&buf, format, ap);
 144         print_trace_line(key, &buf);
 145         strbuf_release(&buf);
 146 }
 147
 148 static void trace_argv_vprintf_fl(const char *file, int line,
 149                                   const char **argv, const char *format,
 150                                   va_list ap)
 151 {
 152         struct strbuf buf = STRBUF_INIT;
 153
 154         if (!prepare_trace_line(file, line, &trace_default_key, &buf))
 155                 return;
 156
 157         strbuf_vaddf(&buf, format, ap);
 158
 159         sq_quote_argv_pretty(&buf, argv);
 160         print_trace_line(&trace_default_key, &buf);
 161         strbuf_release(&buf);
 162 }
 163
 164 void trace_strbuf_fl(const char *file, int line, struct trace_key *key,
 165                      const struct strbuf *data)
 166 {
 167         struct strbuf buf = STRBUF_INIT;
 168
 169         if (!prepare_trace_line(file, line, key, &buf))
 170                 return;
 171
 172         strbuf_addbuf(&buf, data);
 173         print_trace_line(key, &buf);
 174         strbuf_release(&buf);
 175 }
 176
 177 static uint64_t perf_start_times[10];
 178 static int perf_indent;
 179
 180 uint64_t trace_performance_enter(void)
 181 {
 182         uint64_t now;
 183
 184         if (!trace_want(&trace_perf_key))
 185                 return 0;
 186
 187         now = getnanotime();
 188         perf_start_times[perf_indent] = now;
 189         if (perf_indent + 1 < ARRAY_SIZE(perf_start_times))
 190                 perf_indent++;
 191         else
 192                 BUG("Too deep indentation");
 193         return now;
 194 }
 195
 196 static void trace_performance_vprintf_fl(const char *file, int line,
 197                                          uint64_t nanos, const char *format,
 198                                          va_list ap)
 199 {
 200         static const char space[] = "          ";
 201         struct strbuf buf = STRBUF_INIT;
 202
 203         if (!prepare_trace_line(file, line, &trace_perf_key, &buf))
 204                 return;
 205
 206         strbuf_addf(&buf, "performance: %.9f s", (double) nanos / 1000000000);
 207
 208         if (format && *format) {
 209                 if (perf_indent >= strlen(space))
 210                         BUG("Too deep indentation");
 211
 212                 strbuf_addf(&buf, ":%.*s ", perf_indent, space);
 213                 strbuf_vaddf(&buf, format, ap);
 214         }
 215
 216         print_trace_line(&trace_perf_key, &buf);
 217         strbuf_release(&buf);
 218 }
 219
 220 #ifndef HAVE_VARIADIC_MACROS
 221
 222 void trace_printf(const char *format, ...)
 223 {
 224         va_list ap;
 225         va_start(ap, format);
 226         trace_vprintf_fl(NULL, 0, &trace_default_key, format, ap);
 227         va_end(ap);
 228 }
 229
 230 void trace_printf_key(struct trace_key *key, const char *format, ...)
 231 {
 232         va_list ap;
 233         va_start(ap, format);
 234         trace_vprintf_fl(NULL, 0, key, format, ap);
 235         va_end(ap);
 236 }
 237
 238 void trace_argv_printf(const char **argv, const char *format, ...)
 239 {
 240         va_list ap;
 241         va_start(ap, format);
 242         trace_argv_vprintf_fl(NULL, 0, argv, format, ap);
 243         va_end(ap);
 244 }
 245
 246 void trace_strbuf(struct trace_key *key, const struct strbuf *data)
 247 {
 248         trace_strbuf_fl(NULL, 0, key, data);
 249 }
 250
 251 void trace_performance(uint64_t nanos, const char *format, ...)
 252 {
 253         va_list ap;
 254         va_start(ap, format);
 255         trace_performance_vprintf_fl(NULL, 0, nanos, format, ap);
 256         va_end(ap);
 257 }
 258
 259 void trace_performance_since(uint64_t start, const char *format, ...)
 260 {
 261         va_list ap;
 262         va_start(ap, format);
 263         trace_performance_vprintf_fl(NULL, 0, getnanotime() - start,
 264                                      format, ap);
 265         va_end(ap);
 266 }
 267
 268 void trace_performance_leave(const char *format, ...)
 269 {
 270         va_list ap;
 271         uint64_t since;
 272
 273         if (perf_indent)
 274                 perf_indent--;
 275
 276         if (!format) /* Allow callers to leave without tracing anything */
 277                 return;
 278
 279         since = perf_start_times[perf_indent];
 280         va_start(ap, format);
 281         trace_performance_vprintf_fl(NULL, 0, getnanotime() - since,
 282                                      format, ap);
 283         va_end(ap);
 284 }
 285
 286 #else
 287
 288 void trace_printf_key_fl(const char *file, int line, struct trace_key *key,
 289                          const char *format, ...)
 290 {
 291         va_list ap;
 292         va_start(ap, format);
 293         trace_vprintf_fl(file, line, key, format, ap);
 294         va_end(ap);
 295 }
 296
 297 void trace_argv_printf_fl(const char *file, int line, const char **argv,
 298                           const char *format, ...)
 299 {
 300         va_list ap;
 301         va_start(ap, format);
 302         trace_argv_vprintf_fl(file, line, argv, format, ap);
 303         va_end(ap);
 304 }
 305
 306 void trace_performance_fl(const char *file, int line, uint64_t nanos,
 307                               const char *format, ...)
 308 {
 309         va_list ap;
 310         va_start(ap, format);
 311         trace_performance_vprintf_fl(file, line, nanos, format, ap);
 312         va_end(ap);
 313 }
 314
 315 void trace_performance_leave_fl(const char *file, int line,
 316                                 uint64_t nanos, const char *format, ...)
 317 {
 318         va_list ap;
 319         uint64_t since;
 320
 321         if (perf_indent)
 322                 perf_indent--;
 323
 324         if (!format) /* Allow callers to leave without tracing anything */
 325                 return;
 326
 327         since = perf_start_times[perf_indent];
 328         va_start(ap, format);
 329         trace_performance_vprintf_fl(file, line, nanos - since, format, ap);
 330         va_end(ap);
 331 }
 332
 333 #endif /* HAVE_VARIADIC_MACROS */
 334
 335
 336 static const char *quote_crnl(const char *path)
 337 {
 338         static struct strbuf new_path = STRBUF_INIT;
 339
 340         if (!path)
 341                 return NULL;
 342
 343         strbuf_reset(&new_path);
 344
 345         while (*path) {
 346                 switch (*path) {
 347                 case '\\': strbuf_addstr(&new_path, "\\\\"); break;
 348                 case '\n': strbuf_addstr(&new_path, "\\n"); break;
 349                 case '\r': strbuf_addstr(&new_path, "\\r"); break;
 350                 default:
 351                         strbuf_addch(&new_path, *path);
 352                 }
 353                 path++;
 354         }
 355         return new_path.buf;
 356 }
 357
 358 /* FIXME: move prefix to startup_info struct and get rid of this arg */
 359 void trace_repo_setup(const char *prefix)
 360 {
 361         const char *git_work_tree;
 362         char *cwd;
 363
 364         if (!trace_want(&trace_setup_key))
 365                 return;
 366
 367         cwd = xgetcwd();
 368
 369         if (!(git_work_tree = get_git_work_tree()))
 370                 git_work_tree = "(null)";
 371
 372         if (!prefix)
 373                 prefix = "(null)";
 374
 375         trace_printf_key(&trace_setup_key, "setup: git_dir: %s\n", quote_crnl(get_git_dir()));
 376         trace_printf_key(&trace_setup_key, "setup: git_common_dir: %s\n", quote_crnl(get_git_common_dir()));
 377         trace_printf_key(&trace_setup_key, "setup: worktree: %s\n", quote_crnl(git_work_tree));
 378         trace_printf_key(&trace_setup_key, "setup: cwd: %s\n", quote_crnl(cwd));
 379         trace_printf_key(&trace_setup_key, "setup: prefix: %s\n", quote_crnl(prefix));
 380
 381         free(cwd);
 382 }
 383
 384 int trace_want(struct trace_key *key)
 385 {
 386         return !!get_trace_fd(key);
 387 }
 388
 389 #if defined(HAVE_CLOCK_GETTIME) && defined(HAVE_CLOCK_MONOTONIC)
 390
 391 static inline uint64_t highres_nanos(void)
 392 {
 393         struct timespec ts;
 394         if (clock_gettime(CLOCK_MONOTONIC, &ts))
 395                 return 0;
 396         return (uint64_t) ts.tv_sec * 1000000000 + ts.tv_nsec;
 397 }
 398
 399 #elif defined (GIT_WINDOWS_NATIVE)
 400
 401 static inline uint64_t highres_nanos(void)
 402 {
 403         static uint64_t high_ns, scaled_low_ns;
 404         static int scale;
 405         LARGE_INTEGER cnt;
 406
 407         if (!scale) {
 408                 if (!QueryPerformanceFrequency(&cnt))
 409                         return 0;
 410
 411                 /* high_ns = number of ns per cnt.HighPart */
 412                 high_ns = (1000000000LL << 32) / (uint64_t) cnt.QuadPart;
 413
 414                 /*
 415                  * Number of ns per cnt.LowPart is 10^9 / frequency (or
 416                  * high_ns >> 32). For maximum precision, we scale this factor
 417                  * so that it just fits within 32 bit (i.e. won't overflow if
 418                  * multiplied with cnt.LowPart).
 419                  */
 420                 scaled_low_ns = high_ns;
 421                 scale = 32;
 422                 while (scaled_low_ns >= 0x100000000LL) {
 423                         scaled_low_ns >>= 1;
 424                         scale--;
 425                 }
 426         }
 427
 428         /* if QPF worked on initialization, we expect QPC to work as well */
 429         QueryPerformanceCounter(&cnt);
 430
 431         return (high_ns * cnt.HighPart) +
 432                ((scaled_low_ns * cnt.LowPart) >> scale);
 433 }
 434
 435 #else
 436 # define highres_nanos() 0
 437 #endif
 438
 439 static inline uint64_t gettimeofday_nanos(void)
 440 {
 441         struct timeval tv;
 442         gettimeofday(&tv, NULL);
 443         return (uint64_t) tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
 444 }
 445
 446 /*
 447  * Returns nanoseconds since the epoch (01/01/1970), for performance tracing
 448  * (i.e. favoring high precision over wall clock time accuracy).
 449  */
 450 uint64_t getnanotime(void)
 451 {
 452         static uint64_t offset;
 453         if (offset > 1) {
 454                 /* initialization succeeded, return offset + high res time */
 455                 return offset + highres_nanos();
 456         } else if (offset == 1) {
 457                 /* initialization failed, fall back to gettimeofday */
 458                 return gettimeofday_nanos();
 459         } else {
 460                 /* initialize offset if high resolution timer works */
 461                 uint64_t now = gettimeofday_nanos();
 462                 uint64_t highres = highres_nanos();
 463                 if (highres)
 464                         offset = now - highres;
 465                 else
 466                         offset = 1;
 467                 return now;
 468         }
 469 }
 470
 471 static struct strbuf command_line = STRBUF_INIT;
 472
 473 static void print_command_performance_atexit(void)
 474 {
 475         trace_performance_leave("git command:%s", command_line.buf);
 476 }
 477
 478 void trace_command_performance(const char **argv)
 479 {
 480         if (!trace_want(&trace_perf_key))
 481                 return;
 482
 483         if (!command_line.len)
 484                 atexit(print_command_performance_atexit);
 485
 486         strbuf_reset(&command_line);
 487         sq_quote_argv_pretty(&command_line, argv);
 488         trace_performance_enter();
 489 }