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, write to the Free Software
  22  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23  */
  24
  25 #include "cache.h"
  26 #include "quote.h"
  27
  28 /*
  29  * "Normalize" a key argument by converting NULL to our trace_default,
  30  * and otherwise passing through the value. All caller-facing functions
  31  * should normalize their inputs in this way, though most get it
  32  * for free by calling get_trace_fd() (directly or indirectly).
  33  */
  34 static void normalize_trace_key(struct trace_key **key)
  35 {
  36         static struct trace_key trace_default = { "GIT_TRACE" };
  37         if (!*key)
  38                 *key = &trace_default;
  39 }
  40
  41 /* Get a trace file descriptor from "key" env variable. */
  42 static int get_trace_fd(struct trace_key *key)
  43 {
  44         const char *trace;
  45
  46         normalize_trace_key(&key);
  47
  48         /* don't open twice */
  49         if (key->initialized)
  50                 return key->fd;
  51
  52         trace = getenv(key->key);
  53
  54         if (!trace || !strcmp(trace, "") ||
  55             !strcmp(trace, "0") || !strcasecmp(trace, "false"))
  56                 key->fd = 0;
  57         else if (!strcmp(trace, "1") || !strcasecmp(trace, "true"))
  58                 key->fd = STDERR_FILENO;
  59         else if (strlen(trace) == 1 && isdigit(*trace))
  60                 key->fd = atoi(trace);
  61         else if (is_absolute_path(trace)) {
  62                 int fd = open(trace, O_WRONLY | O_APPEND | O_CREAT, 0666);
  63                 if (fd == -1) {
  64                         warning("could not open '%s' for tracing: %s",
  65                                 trace, strerror(errno));
  66                         trace_disable(key);
  67                 } else {
  68                         key->fd = fd;
  69                         key->need_close = 1;
  70                 }
  71         } else {
  72                 warning("unknown trace value for '%s': %s\n"
  73                         "         If you want to trace into a file, then please set %s\n"
  74                         "         to an absolute pathname (starting with /)",
  75                         key->key, trace, key->key);
  76                 trace_disable(key);
  77         }
  78
  79         key->initialized = 1;
  80         return key->fd;
  81 }
  82
  83 void trace_disable(struct trace_key *key)
  84 {
  85         normalize_trace_key(&key);
  86
  87         if (key->need_close)
  88                 close(key->fd);
  89         key->fd = 0;
  90         key->initialized = 1;
  91         key->need_close = 0;
  92 }
  93
  94 static int prepare_trace_line(const char *file, int line,
  95                               struct trace_key *key, struct strbuf *buf)
  96 {
  97         static struct trace_key trace_bare = TRACE_KEY_INIT(BARE);
  98         struct timeval tv;
  99         struct tm tm;
 100         time_t secs;
 101
 102         if (!trace_want(key))
 103                 return 0;
 104
 105         set_try_to_free_routine(NULL);  /* is never reset */
 106
 107         /* unit tests may want to disable additional trace output */
 108         if (trace_want(&trace_bare))
 109                 return 1;
 110
 111         /* print current timestamp */
 112         gettimeofday(&tv, NULL);
 113         secs = tv.tv_sec;
 114         localtime_r(&secs, &tm);
 115         strbuf_addf(buf, "%02d:%02d:%02d.%06ld ", tm.tm_hour, tm.tm_min,
 116                     tm.tm_sec, (long) tv.tv_usec);
 117
 118 #ifdef HAVE_VARIADIC_MACROS
 119         /* print file:line */
 120         strbuf_addf(buf, "%s:%d ", file, line);
 121         /* align trace output (column 40 catches most files names in git) */
 122         while (buf->len < 40)
 123                 strbuf_addch(buf, ' ');
 124 #endif
 125
 126         return 1;
 127 }
 128
 129 static void trace_write(struct trace_key *key, const void *buf, unsigned len)
 130 {
 131         if (write_in_full(get_trace_fd(key), buf, len) < 0) {
 132                 normalize_trace_key(&key);
 133                 warning("unable to write trace for %s: %s",
 134                         key->key, strerror(errno));
 135                 trace_disable(key);
 136         }
 137 }
 138
 139 void trace_verbatim(struct trace_key *key, const void *buf, unsigned len)
 140 {
 141         if (!trace_want(key))
 142                 return;
 143         trace_write(key, buf, len);
 144 }
 145
 146 static void print_trace_line(struct trace_key *key, struct strbuf *buf)
 147 {
 148         strbuf_complete_line(buf);
 149         trace_write(key, buf->buf, buf->len);
 150         strbuf_release(buf);
 151 }
 152
 153 static void trace_vprintf_fl(const char *file, int line, struct trace_key *key,
 154                              const char *format, va_list ap)
 155 {
 156         struct strbuf buf = STRBUF_INIT;
 157
 158         if (!prepare_trace_line(file, line, key, &buf))
 159                 return;
 160
 161         strbuf_vaddf(&buf, format, ap);
 162         print_trace_line(key, &buf);
 163 }
 164
 165 static void trace_argv_vprintf_fl(const char *file, int line,
 166                                   const char **argv, const char *format,
 167                                   va_list ap)
 168 {
 169         struct strbuf buf = STRBUF_INIT;
 170
 171         if (!prepare_trace_line(file, line, NULL, &buf))
 172                 return;
 173
 174         strbuf_vaddf(&buf, format, ap);
 175
 176         sq_quote_argv(&buf, argv, 0);
 177         print_trace_line(NULL, &buf);
 178 }
 179
 180 void trace_strbuf_fl(const char *file, int line, struct trace_key *key,
 181                      const struct strbuf *data)
 182 {
 183         struct strbuf buf = STRBUF_INIT;
 184
 185         if (!prepare_trace_line(file, line, key, &buf))
 186                 return;
 187
 188         strbuf_addbuf(&buf, data);
 189         print_trace_line(key, &buf);
 190 }
 191
 192 static struct trace_key trace_perf_key = TRACE_KEY_INIT(PERFORMANCE);
 193
 194 static void trace_performance_vprintf_fl(const char *file, int line,
 195                                          uint64_t nanos, const char *format,
 196                                          va_list ap)
 197 {
 198         struct strbuf buf = STRBUF_INIT;
 199
 200         if (!prepare_trace_line(file, line, &trace_perf_key, &buf))
 201                 return;
 202
 203         strbuf_addf(&buf, "performance: %.9f s", (double) nanos / 1000000000);
 204
 205         if (format && *format) {
 206                 strbuf_addstr(&buf, ": ");
 207                 strbuf_vaddf(&buf, format, ap);
 208         }
 209
 210         print_trace_line(&trace_perf_key, &buf);
 211 }
 212
 213 #ifndef HAVE_VARIADIC_MACROS
 214
 215 void trace_printf(const char *format, ...)
 216 {
 217         va_list ap;
 218         va_start(ap, format);
 219         trace_vprintf_fl(NULL, 0, NULL, format, ap);
 220         va_end(ap);
 221 }
 222
 223 void trace_printf_key(struct trace_key *key, const char *format, ...)
 224 {
 225         va_list ap;
 226         va_start(ap, format);
 227         trace_vprintf_fl(NULL, 0, key, format, ap);
 228         va_end(ap);
 229 }
 230
 231 void trace_argv_printf(const char **argv, const char *format, ...)
 232 {
 233         va_list ap;
 234         va_start(ap, format);
 235         trace_argv_vprintf_fl(NULL, 0, argv, format, ap);
 236         va_end(ap);
 237 }
 238
 239 void trace_strbuf(struct trace_key *key, const struct strbuf *data)
 240 {
 241         trace_strbuf_fl(NULL, 0, key, data);
 242 }
 243
 244 void trace_performance(uint64_t nanos, const char *format, ...)
 245 {
 246         va_list ap;
 247         va_start(ap, format);
 248         trace_performance_vprintf_fl(NULL, 0, nanos, format, ap);
 249         va_end(ap);
 250 }
 251
 252 void trace_performance_since(uint64_t start, const char *format, ...)
 253 {
 254         va_list ap;
 255         va_start(ap, format);
 256         trace_performance_vprintf_fl(NULL, 0, getnanotime() - start,
 257                                      format, ap);
 258         va_end(ap);
 259 }
 260
 261 #else
 262
 263 void trace_printf_key_fl(const char *file, int line, struct trace_key *key,
 264                          const char *format, ...)
 265 {
 266         va_list ap;
 267         va_start(ap, format);
 268         trace_vprintf_fl(file, line, key, format, ap);
 269         va_end(ap);
 270 }
 271
 272 void trace_argv_printf_fl(const char *file, int line, const char **argv,
 273                           const char *format, ...)
 274 {
 275         va_list ap;
 276         va_start(ap, format);
 277         trace_argv_vprintf_fl(file, line, argv, format, ap);
 278         va_end(ap);
 279 }
 280
 281 void trace_performance_fl(const char *file, int line, uint64_t nanos,
 282                               const char *format, ...)
 283 {
 284         va_list ap;
 285         va_start(ap, format);
 286         trace_performance_vprintf_fl(file, line, nanos, format, ap);
 287         va_end(ap);
 288 }
 289
 290 #endif /* HAVE_VARIADIC_MACROS */
 291
 292
 293 static const char *quote_crnl(const char *path)
 294 {
 295         static struct strbuf new_path = STRBUF_INIT;
 296
 297         if (!path)
 298                 return NULL;
 299
 300         strbuf_reset(&new_path);
 301
 302         while (*path) {
 303                 switch (*path) {
 304                 case '\\': strbuf_addstr(&new_path, "\\\\"); break;
 305                 case '\n': strbuf_addstr(&new_path, "\\n"); break;
 306                 case '\r': strbuf_addstr(&new_path, "\\r"); break;
 307                 default:
 308                         strbuf_addch(&new_path, *path);
 309                 }
 310                 path++;
 311         }
 312         return new_path.buf;
 313 }
 314
 315 /* FIXME: move prefix to startup_info struct and get rid of this arg */
 316 void trace_repo_setup(const char *prefix)
 317 {
 318         static struct trace_key key = TRACE_KEY_INIT(SETUP);
 319         const char *git_work_tree;
 320         char *cwd;
 321
 322         if (!trace_want(&key))
 323                 return;
 324
 325         cwd = xgetcwd();
 326
 327         if (!(git_work_tree = get_git_work_tree()))
 328                 git_work_tree = "(null)";
 329
 330         if (!prefix)
 331                 prefix = "(null)";
 332
 333         trace_printf_key(&key, "setup: git_dir: %s\n", quote_crnl(get_git_dir()));
 334         trace_printf_key(&key, "setup: git_common_dir: %s\n", quote_crnl(get_git_common_dir()));
 335         trace_printf_key(&key, "setup: worktree: %s\n", quote_crnl(git_work_tree));
 336         trace_printf_key(&key, "setup: cwd: %s\n", quote_crnl(cwd));
 337         trace_printf_key(&key, "setup: prefix: %s\n", quote_crnl(prefix));
 338
 339         free(cwd);
 340 }
 341
 342 int trace_want(struct trace_key *key)
 343 {
 344         return !!get_trace_fd(key);
 345 }
 346
 347 #if defined(HAVE_CLOCK_GETTIME) && defined(HAVE_CLOCK_MONOTONIC)
 348
 349 static inline uint64_t highres_nanos(void)
 350 {
 351         struct timespec ts;
 352         if (clock_gettime(CLOCK_MONOTONIC, &ts))
 353                 return 0;
 354         return (uint64_t) ts.tv_sec * 1000000000 + ts.tv_nsec;
 355 }
 356
 357 #elif defined (GIT_WINDOWS_NATIVE)
 358
 359 static inline uint64_t highres_nanos(void)
 360 {
 361         static uint64_t high_ns, scaled_low_ns;
 362         static int scale;
 363         LARGE_INTEGER cnt;
 364
 365         if (!scale) {
 366                 if (!QueryPerformanceFrequency(&cnt))
 367                         return 0;
 368
 369                 /* high_ns = number of ns per cnt.HighPart */
 370                 high_ns = (1000000000LL << 32) / (uint64_t) cnt.QuadPart;
 371
 372                 /*
 373                  * Number of ns per cnt.LowPart is 10^9 / frequency (or
 374                  * high_ns >> 32). For maximum precision, we scale this factor
 375                  * so that it just fits within 32 bit (i.e. won't overflow if
 376                  * multiplied with cnt.LowPart).
 377                  */
 378                 scaled_low_ns = high_ns;
 379                 scale = 32;
 380                 while (scaled_low_ns >= 0x100000000LL) {
 381                         scaled_low_ns >>= 1;
 382                         scale--;
 383                 }
 384         }
 385
 386         /* if QPF worked on initialization, we expect QPC to work as well */
 387         QueryPerformanceCounter(&cnt);
 388
 389         return (high_ns * cnt.HighPart) +
 390                ((scaled_low_ns * cnt.LowPart) >> scale);
 391 }
 392
 393 #else
 394 # define highres_nanos() 0
 395 #endif
 396
 397 static inline uint64_t gettimeofday_nanos(void)
 398 {
 399         struct timeval tv;
 400         gettimeofday(&tv, NULL);
 401         return (uint64_t) tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
 402 }
 403
 404 /*
 405  * Returns nanoseconds since the epoch (01/01/1970), for performance tracing
 406  * (i.e. favoring high precision over wall clock time accuracy).
 407  */
 408 uint64_t getnanotime(void)
 409 {
 410         static uint64_t offset;
 411         if (offset > 1) {
 412                 /* initialization succeeded, return offset + high res time */
 413                 return offset + highres_nanos();
 414         } else if (offset == 1) {
 415                 /* initialization failed, fall back to gettimeofday */
 416                 return gettimeofday_nanos();
 417         } else {
 418                 /* initialize offset if high resolution timer works */
 419                 uint64_t now = gettimeofday_nanos();
 420                 uint64_t highres = highres_nanos();
 421                 if (highres)
 422                         offset = now - highres;
 423                 else
 424                         offset = 1;
 425                 return now;
 426         }
 427 }
 428
 429 static uint64_t command_start_time;
 430 static struct strbuf command_line = STRBUF_INIT;
 431
 432 static void print_command_performance_atexit(void)
 433 {
 434         trace_performance_since(command_start_time, "git command:%s",
 435                                 command_line.buf);
 436 }
 437
 438 void trace_command_performance(const char **argv)
 439 {
 440         if (!trace_want(&trace_perf_key))
 441                 return;
 442
 443         if (!command_start_time)
 444                 atexit(print_command_performance_atexit);
 445
 446         strbuf_reset(&command_line);
 447         sq_quote_argv(&command_line, argv, 0);
 448         command_start_time = getnanotime();
 449 }