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, const char *override_envvar)
  33 {
  34         const char *trace;
  35
  36         /* don't open twice */
  37         if (key->initialized)
  38                 return key->fd;
  39
  40         trace = override_envvar ? override_envvar : 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_override_envvar(struct trace_key *key, const char *value)
  72 {
  73         trace_disable(key);
  74         key->initialized = 0;
  75
  76         /*
  77          * Invoke get_trace_fd() to initialize key using the given value
  78          * instead of the value of the environment variable.
  79          */
  80         get_trace_fd(key, value);
  81 }
  82
  83 void trace_disable(struct trace_key *key)
  84 {
  85         if (key->need_close)
  86                 close(key->fd);
  87         key->fd = 0;
  88         key->initialized = 1;
  89         key->need_close = 0;
  90 }
  91
  92 static int prepare_trace_line(const char *file, int line,
  93                               struct trace_key *key, struct strbuf *buf)
  94 {
  95         static struct trace_key trace_bare = TRACE_KEY_INIT(BARE);
  96         struct timeval tv;
  97         struct tm tm;
  98         time_t secs;
  99
 100         if (!trace_want(key))
 101                 return 0;
 102
 103         /* unit tests may want to disable additional trace output */
 104         if (trace_want(&trace_bare))
 105                 return 1;
 106
 107         /* print current timestamp */
 108         gettimeofday(&tv, NULL);
 109         secs = tv.tv_sec;
 110         localtime_r(&secs, &tm);
 111         strbuf_addf(buf, "%02d:%02d:%02d.%06ld ", tm.tm_hour, tm.tm_min,
 112                     tm.tm_sec, (long) tv.tv_usec);
 113
 114 #ifdef HAVE_VARIADIC_MACROS
 115         /* print file:line */
 116         strbuf_addf(buf, "%s:%d ", file, line);
 117         /* align trace output (column 40 catches most files names in git) */
 118         while (buf->len < 40)
 119                 strbuf_addch(buf, ' ');
 120 #endif
 121
 122         return 1;
 123 }
 124
 125 static void trace_write(struct trace_key *key, const void *buf, unsigned len)
 126 {
 127         if (write_in_full(get_trace_fd(key, NULL), buf, len) < 0) {
 128                 warning("unable to write trace for %s: %s",
 129                         key->key, strerror(errno));
 130                 trace_disable(key);
 131         }
 132 }
 133
 134 void trace_verbatim(struct trace_key *key, const void *buf, unsigned len)
 135 {
 136         if (!trace_want(key))
 137                 return;
 138         trace_write(key, buf, len);
 139 }
 140
 141 static void print_trace_line(struct trace_key *key, struct strbuf *buf)
 142 {
 143         strbuf_complete_line(buf);
 144         trace_write(key, buf->buf, buf->len);
 145 }
 146
 147 static void trace_vprintf_fl(const char *file, int line, struct trace_key *key,
 148                              const char *format, va_list ap)
 149 {
 150         struct strbuf buf = STRBUF_INIT;
 151
 152         if (!prepare_trace_line(file, line, key, &buf))
 153                 return;
 154
 155         strbuf_vaddf(&buf, format, ap);
 156         print_trace_line(key, &buf);
 157         strbuf_release(&buf);
 158 }
 159
 160 static void trace_argv_vprintf_fl(const char *file, int line,
 161                                   const char **argv, const char *format,
 162                                   va_list ap)
 163 {
 164         struct strbuf buf = STRBUF_INIT;
 165
 166         if (!prepare_trace_line(file, line, &trace_default_key, &buf))
 167                 return;
 168
 169         strbuf_vaddf(&buf, format, ap);
 170
 171         sq_quote_argv_pretty(&buf, argv);
 172         print_trace_line(&trace_default_key, &buf);
 173         strbuf_release(&buf);
 174 }
 175
 176 void trace_strbuf_fl(const char *file, int line, struct trace_key *key,
 177                      const struct strbuf *data)
 178 {
 179         struct strbuf buf = STRBUF_INIT;
 180
 181         if (!prepare_trace_line(file, line, key, &buf))
 182                 return;
 183
 184         strbuf_addbuf(&buf, data);
 185         print_trace_line(key, &buf);
 186         strbuf_release(&buf);
 187 }
 188
 189 static uint64_t perf_start_times[10];
 190 static int perf_indent;
 191
 192 uint64_t trace_performance_enter(void)
 193 {
 194         uint64_t now;
 195
 196         if (!trace_want(&trace_perf_key))
 197                 return 0;
 198
 199         now = getnanotime();
 200         perf_start_times[perf_indent] = now;
 201         if (perf_indent + 1 < ARRAY_SIZE(perf_start_times))
 202                 perf_indent++;
 203         else
 204                 BUG("Too deep indentation");
 205         return now;
 206 }
 207
 208 static void trace_performance_vprintf_fl(const char *file, int line,
 209                                          uint64_t nanos, const char *format,
 210                                          va_list ap)
 211 {
 212         static const char space[] = "          ";
 213         struct strbuf buf = STRBUF_INIT;
 214
 215         if (!prepare_trace_line(file, line, &trace_perf_key, &buf))
 216                 return;
 217
 218         strbuf_addf(&buf, "performance: %.9f s", (double) nanos / 1000000000);
 219
 220         if (format && *format) {
 221                 if (perf_indent >= strlen(space))
 222                         BUG("Too deep indentation");
 223
 224                 strbuf_addf(&buf, ":%.*s ", perf_indent, space);
 225                 strbuf_vaddf(&buf, format, ap);
 226         }
 227
 228         print_trace_line(&trace_perf_key, &buf);
 229         strbuf_release(&buf);
 230 }
 231
 232 #ifndef HAVE_VARIADIC_MACROS
 233
 234 void trace_printf(const char *format, ...)
 235 {
 236         va_list ap;
 237         va_start(ap, format);
 238         trace_vprintf_fl(NULL, 0, &trace_default_key, format, ap);
 239         va_end(ap);
 240 }
 241
 242 void trace_printf_key(struct trace_key *key, const char *format, ...)
 243 {
 244         va_list ap;
 245         va_start(ap, format);
 246         trace_vprintf_fl(NULL, 0, key, format, ap);
 247         va_end(ap);
 248 }
 249
 250 void trace_argv_printf(const char **argv, const char *format, ...)
 251 {
 252         va_list ap;
 253         va_start(ap, format);
 254         trace_argv_vprintf_fl(NULL, 0, argv, format, ap);
 255         va_end(ap);
 256 }
 257
 258 void trace_strbuf(struct trace_key *key, const struct strbuf *data)
 259 {
 260         trace_strbuf_fl(NULL, 0, key, data);
 261 }
 262
 263 void trace_performance(uint64_t nanos, const char *format, ...)
 264 {
 265         va_list ap;
 266         va_start(ap, format);
 267         trace_performance_vprintf_fl(NULL, 0, nanos, format, ap);
 268         va_end(ap);
 269 }
 270
 271 void trace_performance_since(uint64_t start, const char *format, ...)
 272 {
 273         va_list ap;
 274         va_start(ap, format);
 275         trace_performance_vprintf_fl(NULL, 0, getnanotime() - start,
 276                                      format, ap);
 277         va_end(ap);
 278 }
 279
 280 void trace_performance_leave(const char *format, ...)
 281 {
 282         va_list ap;
 283         uint64_t since;
 284
 285         if (perf_indent)
 286                 perf_indent--;
 287
 288         if (!format) /* Allow callers to leave without tracing anything */
 289                 return;
 290
 291         since = perf_start_times[perf_indent];
 292         va_start(ap, format);
 293         trace_performance_vprintf_fl(NULL, 0, getnanotime() - since,
 294                                      format, ap);
 295         va_end(ap);
 296 }
 297
 298 #else
 299
 300 void trace_printf_key_fl(const char *file, int line, struct trace_key *key,
 301                          const char *format, ...)
 302 {
 303         va_list ap;
 304         va_start(ap, format);
 305         trace_vprintf_fl(file, line, key, format, ap);
 306         va_end(ap);
 307 }
 308
 309 void trace_argv_printf_fl(const char *file, int line, const char **argv,
 310                           const char *format, ...)
 311 {
 312         va_list ap;
 313         va_start(ap, format);
 314         trace_argv_vprintf_fl(file, line, argv, format, ap);
 315         va_end(ap);
 316 }
 317
 318 void trace_performance_fl(const char *file, int line, uint64_t nanos,
 319                               const char *format, ...)
 320 {
 321         va_list ap;
 322         va_start(ap, format);
 323         trace_performance_vprintf_fl(file, line, nanos, format, ap);
 324         va_end(ap);
 325 }
 326
 327 void trace_performance_leave_fl(const char *file, int line,
 328                                 uint64_t nanos, const char *format, ...)
 329 {
 330         va_list ap;
 331         uint64_t since;
 332
 333         if (perf_indent)
 334                 perf_indent--;
 335
 336         if (!format) /* Allow callers to leave without tracing anything */
 337                 return;
 338
 339         since = perf_start_times[perf_indent];
 340         va_start(ap, format);
 341         trace_performance_vprintf_fl(file, line, nanos - since, format, ap);
 342         va_end(ap);
 343 }
 344
 345 #endif /* HAVE_VARIADIC_MACROS */
 346
 347
 348 static const char *quote_crnl(const char *path)
 349 {
 350         static struct strbuf new_path = STRBUF_INIT;
 351
 352         if (!path)
 353                 return NULL;
 354
 355         strbuf_reset(&new_path);
 356
 357         while (*path) {
 358                 switch (*path) {
 359                 case '\\': strbuf_addstr(&new_path, "\\\\"); break;
 360                 case '\n': strbuf_addstr(&new_path, "\\n"); break;
 361                 case '\r': strbuf_addstr(&new_path, "\\r"); break;
 362                 default:
 363                         strbuf_addch(&new_path, *path);
 364                 }
 365                 path++;
 366         }
 367         return new_path.buf;
 368 }
 369
 370 /* FIXME: move prefix to startup_info struct and get rid of this arg */
 371 void trace_repo_setup(const char *prefix)
 372 {
 373         const char *git_work_tree;
 374         char *cwd;
 375
 376         if (!trace_want(&trace_setup_key))
 377                 return;
 378
 379         cwd = xgetcwd();
 380
 381         if (!(git_work_tree = get_git_work_tree()))
 382                 git_work_tree = "(null)";
 383
 384         if (!prefix)
 385                 prefix = "(null)";
 386
 387         trace_printf_key(&trace_setup_key, "setup: git_dir: %s\n", quote_crnl(get_git_dir()));
 388         trace_printf_key(&trace_setup_key, "setup: git_common_dir: %s\n", quote_crnl(get_git_common_dir()));
 389         trace_printf_key(&trace_setup_key, "setup: worktree: %s\n", quote_crnl(git_work_tree));
 390         trace_printf_key(&trace_setup_key, "setup: cwd: %s\n", quote_crnl(cwd));
 391         trace_printf_key(&trace_setup_key, "setup: prefix: %s\n", quote_crnl(prefix));
 392
 393         free(cwd);
 394 }
 395
 396 int trace_want(struct trace_key *key)
 397 {
 398         return !!get_trace_fd(key, NULL);
 399 }
 400
 401 #if defined(HAVE_CLOCK_GETTIME) && defined(HAVE_CLOCK_MONOTONIC)
 402
 403 static inline uint64_t highres_nanos(void)
 404 {
 405         struct timespec ts;
 406         if (clock_gettime(CLOCK_MONOTONIC, &ts))
 407                 return 0;
 408         return (uint64_t) ts.tv_sec * 1000000000 + ts.tv_nsec;
 409 }
 410
 411 #elif defined (GIT_WINDOWS_NATIVE)
 412
 413 static inline uint64_t highres_nanos(void)
 414 {
 415         static uint64_t high_ns, scaled_low_ns;
 416         static int scale;
 417         LARGE_INTEGER cnt;
 418
 419         if (!scale) {
 420                 if (!QueryPerformanceFrequency(&cnt))
 421                         return 0;
 422
 423                 /* high_ns = number of ns per cnt.HighPart */
 424                 high_ns = (1000000000LL << 32) / (uint64_t) cnt.QuadPart;
 425
 426                 /*
 427                  * Number of ns per cnt.LowPart is 10^9 / frequency (or
 428                  * high_ns >> 32). For maximum precision, we scale this factor
 429                  * so that it just fits within 32 bit (i.e. won't overflow if
 430                  * multiplied with cnt.LowPart).
 431                  */
 432                 scaled_low_ns = high_ns;
 433                 scale = 32;
 434                 while (scaled_low_ns >= 0x100000000LL) {
 435                         scaled_low_ns >>= 1;
 436                         scale--;
 437                 }
 438         }
 439
 440         /* if QPF worked on initialization, we expect QPC to work as well */
 441         QueryPerformanceCounter(&cnt);
 442
 443         return (high_ns * cnt.HighPart) +
 444                ((scaled_low_ns * cnt.LowPart) >> scale);
 445 }
 446
 447 #else
 448 # define highres_nanos() 0
 449 #endif
 450
 451 static inline uint64_t gettimeofday_nanos(void)
 452 {
 453         struct timeval tv;
 454         gettimeofday(&tv, NULL);
 455         return (uint64_t) tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
 456 }
 457
 458 /*
 459  * Returns nanoseconds since the epoch (01/01/1970), for performance tracing
 460  * (i.e. favoring high precision over wall clock time accuracy).
 461  */
 462 uint64_t getnanotime(void)
 463 {
 464         static uint64_t offset;
 465         if (offset > 1) {
 466                 /* initialization succeeded, return offset + high res time */
 467                 return offset + highres_nanos();
 468         } else if (offset == 1) {
 469                 /* initialization failed, fall back to gettimeofday */
 470                 return gettimeofday_nanos();
 471         } else {
 472                 /* initialize offset if high resolution timer works */
 473                 uint64_t now = gettimeofday_nanos();
 474                 uint64_t highres = highres_nanos();
 475                 if (highres)
 476                         offset = now - highres;
 477                 else
 478                         offset = 1;
 479                 return now;
 480         }
 481 }
 482
 483 static struct strbuf command_line = STRBUF_INIT;
 484
 485 static void print_command_performance_atexit(void)
 486 {
 487         trace_performance_leave("git command:%s", command_line.buf);
 488 }
 489
 490 void trace_command_performance(const char **argv)
 491 {
 492         if (!trace_want(&trace_perf_key))
 493                 return;
 494
 495         if (!command_line.len)
 496                 atexit(print_command_performance_atexit);
 497
 498         strbuf_reset(&command_line);
 499         sq_quote_argv_pretty(&command_line, argv);
 500         trace_performance_enter();
 501 }