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         set_try_to_free_routine(NULL);  /* is never reset */
  92
  93         /* unit tests may want to disable additional trace output */
  94         if (trace_want(&trace_bare))
  95                 return 1;
  96
  97         /* print current timestamp */
  98         gettimeofday(&tv, NULL);
  99         secs = tv.tv_sec;
 100         localtime_r(&secs, &tm);
 101         strbuf_addf(buf, "%02d:%02d:%02d.%06ld ", tm.tm_hour, tm.tm_min,
 102                     tm.tm_sec, (long) tv.tv_usec);
 103
 104 #ifdef HAVE_VARIADIC_MACROS
 105         /* print file:line */
 106         strbuf_addf(buf, "%s:%d ", file, line);
 107         /* align trace output (column 40 catches most files names in git) */
 108         while (buf->len < 40)
 109                 strbuf_addch(buf, ' ');
 110 #endif
 111
 112         return 1;
 113 }
 114
 115 static void trace_write(struct trace_key *key, const void *buf, unsigned len)
 116 {
 117         if (write_in_full(get_trace_fd(key), buf, len) < 0) {
 118                 warning("unable to write trace for %s: %s",
 119                         key->key, strerror(errno));
 120                 trace_disable(key);
 121         }
 122 }
 123
 124 void trace_verbatim(struct trace_key *key, const void *buf, unsigned len)
 125 {
 126         if (!trace_want(key))
 127                 return;
 128         trace_write(key, buf, len);
 129 }
 130
 131 static void print_trace_line(struct trace_key *key, struct strbuf *buf)
 132 {
 133         strbuf_complete_line(buf);
 134         trace_write(key, buf->buf, buf->len);
 135 }
 136
 137 static void trace_vprintf_fl(const char *file, int line, struct trace_key *key,
 138                              const char *format, va_list ap)
 139 {
 140         struct strbuf buf = STRBUF_INIT;
 141
 142         if (!prepare_trace_line(file, line, key, &buf))
 143                 return;
 144
 145         strbuf_vaddf(&buf, format, ap);
 146         print_trace_line(key, &buf);
 147         strbuf_release(&buf);
 148 }
 149
 150 static void trace_argv_vprintf_fl(const char *file, int line,
 151                                   const char **argv, const char *format,
 152                                   va_list ap)
 153 {
 154         struct strbuf buf = STRBUF_INIT;
 155
 156         if (!prepare_trace_line(file, line, &trace_default_key, &buf))
 157                 return;
 158
 159         strbuf_vaddf(&buf, format, ap);
 160
 161         sq_quote_argv_pretty(&buf, argv);
 162         print_trace_line(&trace_default_key, &buf);
 163         strbuf_release(&buf);
 164 }
 165
 166 void trace_strbuf_fl(const char *file, int line, struct trace_key *key,
 167                      const struct strbuf *data)
 168 {
 169         struct strbuf buf = STRBUF_INIT;
 170
 171         if (!prepare_trace_line(file, line, key, &buf))
 172                 return;
 173
 174         strbuf_addbuf(&buf, data);
 175         print_trace_line(key, &buf);
 176         strbuf_release(&buf);
 177 }
 178
 179 static uint64_t perf_start_times[10];
 180 static int perf_indent;
 181
 182 uint64_t trace_performance_enter(void)
 183 {
 184         uint64_t now;
 185
 186         if (!trace_want(&trace_perf_key))
 187                 return 0;
 188
 189         now = getnanotime();
 190         perf_start_times[perf_indent] = now;
 191         if (perf_indent + 1 < ARRAY_SIZE(perf_start_times))
 192                 perf_indent++;
 193         else
 194                 BUG("Too deep indentation");
 195         return now;
 196 }
 197
 198 static void trace_performance_vprintf_fl(const char *file, int line,
 199                                          uint64_t nanos, const char *format,
 200                                          va_list ap)
 201 {
 202         static const char space[] = "          ";
 203         struct strbuf buf = STRBUF_INIT;
 204
 205         if (!prepare_trace_line(file, line, &trace_perf_key, &buf))
 206                 return;
 207
 208         strbuf_addf(&buf, "performance: %.9f s", (double) nanos / 1000000000);
 209
 210         if (format && *format) {
 211                 if (perf_indent >= strlen(space))
 212                         BUG("Too deep indentation");
 213
 214                 strbuf_addf(&buf, ":%.*s ", perf_indent, space);
 215                 strbuf_vaddf(&buf, format, ap);
 216         }
 217
 218         print_trace_line(&trace_perf_key, &buf);
 219         strbuf_release(&buf);
 220 }
 221
 222 #ifndef HAVE_VARIADIC_MACROS
 223
 224 void trace_printf(const char *format, ...)
 225 {
 226         va_list ap;
 227         va_start(ap, format);
 228         trace_vprintf_fl(NULL, 0, &trace_default_key, format, ap);
 229         va_end(ap);
 230 }
 231
 232 void trace_printf_key(struct trace_key *key, const char *format, ...)
 233 {
 234         va_list ap;
 235         va_start(ap, format);
 236         trace_vprintf_fl(NULL, 0, key, format, ap);
 237         va_end(ap);
 238 }
 239
 240 void trace_argv_printf(const char **argv, const char *format, ...)
 241 {
 242         va_list ap;
 243         va_start(ap, format);
 244         trace_argv_vprintf_fl(NULL, 0, argv, format, ap);
 245         va_end(ap);
 246 }
 247
 248 void trace_strbuf(struct trace_key *key, const struct strbuf *data)
 249 {
 250         trace_strbuf_fl(NULL, 0, key, data);
 251 }
 252
 253 void trace_performance(uint64_t nanos, const char *format, ...)
 254 {
 255         va_list ap;
 256         va_start(ap, format);
 257         trace_performance_vprintf_fl(NULL, 0, nanos, format, ap);
 258         va_end(ap);
 259 }
 260
 261 void trace_performance_since(uint64_t start, const char *format, ...)
 262 {
 263         va_list ap;
 264         va_start(ap, format);
 265         trace_performance_vprintf_fl(NULL, 0, getnanotime() - start,
 266                                      format, ap);
 267         va_end(ap);
 268 }
 269
 270 void trace_performance_leave(const char *format, ...)
 271 {
 272         va_list ap;
 273         uint64_t since;
 274
 275         if (perf_indent)
 276                 perf_indent--;
 277
 278         if (!format) /* Allow callers to leave without tracing anything */
 279                 return;
 280
 281         since = perf_start_times[perf_indent];
 282         va_start(ap, format);
 283         trace_performance_vprintf_fl(NULL, 0, getnanotime() - since,
 284                                      format, ap);
 285         va_end(ap);
 286 }
 287
 288 #else
 289
 290 void trace_printf_key_fl(const char *file, int line, struct trace_key *key,
 291                          const char *format, ...)
 292 {
 293         va_list ap;
 294         va_start(ap, format);
 295         trace_vprintf_fl(file, line, key, format, ap);
 296         va_end(ap);
 297 }
 298
 299 void trace_argv_printf_fl(const char *file, int line, const char **argv,
 300                           const char *format, ...)
 301 {
 302         va_list ap;
 303         va_start(ap, format);
 304         trace_argv_vprintf_fl(file, line, argv, format, ap);
 305         va_end(ap);
 306 }
 307
 308 void trace_performance_fl(const char *file, int line, uint64_t nanos,
 309                               const char *format, ...)
 310 {
 311         va_list ap;
 312         va_start(ap, format);
 313         trace_performance_vprintf_fl(file, line, nanos, format, ap);
 314         va_end(ap);
 315 }
 316
 317 void trace_performance_leave_fl(const char *file, int line,
 318                                 uint64_t nanos, const char *format, ...)
 319 {
 320         va_list ap;
 321         uint64_t since;
 322
 323         if (perf_indent)
 324                 perf_indent--;
 325
 326         if (!format) /* Allow callers to leave without tracing anything */
 327                 return;
 328
 329         since = perf_start_times[perf_indent];
 330         va_start(ap, format);
 331         trace_performance_vprintf_fl(file, line, nanos - since, format, ap);
 332         va_end(ap);
 333 }
 334
 335 #endif /* HAVE_VARIADIC_MACROS */
 336
 337
 338 static const char *quote_crnl(const char *path)
 339 {
 340         static struct strbuf new_path = STRBUF_INIT;
 341
 342         if (!path)
 343                 return NULL;
 344
 345         strbuf_reset(&new_path);
 346
 347         while (*path) {
 348                 switch (*path) {
 349                 case '\\': strbuf_addstr(&new_path, "\\\\"); break;
 350                 case '\n': strbuf_addstr(&new_path, "\\n"); break;
 351                 case '\r': strbuf_addstr(&new_path, "\\r"); break;
 352                 default:
 353                         strbuf_addch(&new_path, *path);
 354                 }
 355                 path++;
 356         }
 357         return new_path.buf;
 358 }
 359
 360 /* FIXME: move prefix to startup_info struct and get rid of this arg */
 361 void trace_repo_setup(const char *prefix)
 362 {
 363         const char *git_work_tree;
 364         char *cwd;
 365
 366         if (!trace_want(&trace_setup_key))
 367                 return;
 368
 369         cwd = xgetcwd();
 370
 371         if (!(git_work_tree = get_git_work_tree()))
 372                 git_work_tree = "(null)";
 373
 374         if (!prefix)
 375                 prefix = "(null)";
 376
 377         trace_printf_key(&trace_setup_key, "setup: git_dir: %s\n", quote_crnl(get_git_dir()));
 378         trace_printf_key(&trace_setup_key, "setup: git_common_dir: %s\n", quote_crnl(get_git_common_dir()));
 379         trace_printf_key(&trace_setup_key, "setup: worktree: %s\n", quote_crnl(git_work_tree));
 380         trace_printf_key(&trace_setup_key, "setup: cwd: %s\n", quote_crnl(cwd));
 381         trace_printf_key(&trace_setup_key, "setup: prefix: %s\n", quote_crnl(prefix));
 382
 383         free(cwd);
 384 }
 385
 386 int trace_want(struct trace_key *key)
 387 {
 388         return !!get_trace_fd(key);
 389 }
 390
 391 #if defined(HAVE_CLOCK_GETTIME) && defined(HAVE_CLOCK_MONOTONIC)
 392
 393 static inline uint64_t highres_nanos(void)
 394 {
 395         struct timespec ts;
 396         if (clock_gettime(CLOCK_MONOTONIC, &ts))
 397                 return 0;
 398         return (uint64_t) ts.tv_sec * 1000000000 + ts.tv_nsec;
 399 }
 400
 401 #elif defined (GIT_WINDOWS_NATIVE)
 402
 403 static inline uint64_t highres_nanos(void)
 404 {
 405         static uint64_t high_ns, scaled_low_ns;
 406         static int scale;
 407         LARGE_INTEGER cnt;
 408
 409         if (!scale) {
 410                 if (!QueryPerformanceFrequency(&cnt))
 411                         return 0;
 412
 413                 /* high_ns = number of ns per cnt.HighPart */
 414                 high_ns = (1000000000LL << 32) / (uint64_t) cnt.QuadPart;
 415
 416                 /*
 417                  * Number of ns per cnt.LowPart is 10^9 / frequency (or
 418                  * high_ns >> 32). For maximum precision, we scale this factor
 419                  * so that it just fits within 32 bit (i.e. won't overflow if
 420                  * multiplied with cnt.LowPart).
 421                  */
 422                 scaled_low_ns = high_ns;
 423                 scale = 32;
 424                 while (scaled_low_ns >= 0x100000000LL) {
 425                         scaled_low_ns >>= 1;
 426                         scale--;
 427                 }
 428         }
 429
 430         /* if QPF worked on initialization, we expect QPC to work as well */
 431         QueryPerformanceCounter(&cnt);
 432
 433         return (high_ns * cnt.HighPart) +
 434                ((scaled_low_ns * cnt.LowPart) >> scale);
 435 }
 436
 437 #else
 438 # define highres_nanos() 0
 439 #endif
 440
 441 static inline uint64_t gettimeofday_nanos(void)
 442 {
 443         struct timeval tv;
 444         gettimeofday(&tv, NULL);
 445         return (uint64_t) tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
 446 }
 447
 448 /*
 449  * Returns nanoseconds since the epoch (01/01/1970), for performance tracing
 450  * (i.e. favoring high precision over wall clock time accuracy).
 451  */
 452 uint64_t getnanotime(void)
 453 {
 454         static uint64_t offset;
 455         if (offset > 1) {
 456                 /* initialization succeeded, return offset + high res time */
 457                 return offset + highres_nanos();
 458         } else if (offset == 1) {
 459                 /* initialization failed, fall back to gettimeofday */
 460                 return gettimeofday_nanos();
 461         } else {
 462                 /* initialize offset if high resolution timer works */
 463                 uint64_t now = gettimeofday_nanos();
 464                 uint64_t highres = highres_nanos();
 465                 if (highres)
 466                         offset = now - highres;
 467                 else
 468                         offset = 1;
 469                 return now;
 470         }
 471 }
 472
 473 static struct strbuf command_line = STRBUF_INIT;
 474
 475 static void print_command_performance_atexit(void)
 476 {
 477         trace_performance_leave("git command:%s", command_line.buf);
 478 }
 479
 480 void trace_command_performance(const char **argv)
 481 {
 482         if (!trace_want(&trace_perf_key))
 483                 return;
 484
 485         if (!command_line.len)
 486                 atexit(print_command_performance_atexit);
 487
 488         strbuf_reset(&command_line);
 489         sq_quote_argv_pretty(&command_line, argv);
 490         trace_performance_enter();
 491 }