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\n"
  65                                 "         Defaulting to tracing on stderr...",
  66                                 trace, strerror(errno));
  67                         key->fd = STDERR_FILENO;
  68                 } else {
  69                         key->fd = fd;
  70                         key->need_close = 1;
  71                 }
  72         } else {
  73                 warning("unknown trace value for '%s': %s\n"
  74                         "         If you want to trace into a file, then please set %s\n"
  75                         "         to an absolute pathname (starting with /)\n"
  76                         "         Defaulting to tracing on stderr...",
  77                         key->key, trace, key->key);
  78                 key->fd = STDERR_FILENO;
  79         }
  80
  81         key->initialized = 1;
  82         return key->fd;
  83 }
  84
  85 void trace_disable(struct trace_key *key)
  86 {
  87         normalize_trace_key(&key);
  88
  89         if (key->need_close)
  90                 close(key->fd);
  91         key->fd = 0;
  92         key->initialized = 1;
  93         key->need_close = 0;
  94 }
  95
  96 static int prepare_trace_line(const char *file, int line,
  97                               struct trace_key *key, struct strbuf *buf)
  98 {
  99         static struct trace_key trace_bare = TRACE_KEY_INIT(BARE);
 100         struct timeval tv;
 101         struct tm tm;
 102         time_t secs;
 103
 104         if (!trace_want(key))
 105                 return 0;
 106
 107         set_try_to_free_routine(NULL);  /* is never reset */
 108
 109         /* unit tests may want to disable additional trace output */
 110         if (trace_want(&trace_bare))
 111                 return 1;
 112
 113         /* print current timestamp */
 114         gettimeofday(&tv, NULL);
 115         secs = tv.tv_sec;
 116         localtime_r(&secs, &tm);
 117         strbuf_addf(buf, "%02d:%02d:%02d.%06ld ", tm.tm_hour, tm.tm_min,
 118                     tm.tm_sec, (long) tv.tv_usec);
 119
 120 #ifdef HAVE_VARIADIC_MACROS
 121         /* print file:line */
 122         strbuf_addf(buf, "%s:%d ", file, line);
 123         /* align trace output (column 40 catches most files names in git) */
 124         while (buf->len < 40)
 125                 strbuf_addch(buf, ' ');
 126 #endif
 127
 128         return 1;
 129 }
 130
 131 static void trace_write(struct trace_key *key, const void *buf, unsigned len)
 132 {
 133         if (write_in_full(get_trace_fd(key), buf, len) < 0) {
 134                 normalize_trace_key(&key);
 135                 warning("unable to write trace for %s: %s",
 136                         key->key, strerror(errno));
 137         }
 138 }
 139
 140 void trace_verbatim(struct trace_key *key, const void *buf, unsigned len)
 141 {
 142         if (!trace_want(key))
 143                 return;
 144         trace_write(key, buf, len);
 145 }
 146
 147 static void print_trace_line(struct trace_key *key, struct strbuf *buf)
 148 {
 149         strbuf_complete_line(buf);
 150         trace_write(key, buf->buf, buf->len);
 151         strbuf_release(buf);
 152 }
 153
 154 static void trace_vprintf_fl(const char *file, int line, struct trace_key *key,
 155                              const char *format, va_list ap)
 156 {
 157         struct strbuf buf = STRBUF_INIT;
 158
 159         if (!prepare_trace_line(file, line, key, &buf))
 160                 return;
 161
 162         strbuf_vaddf(&buf, format, ap);
 163         print_trace_line(key, &buf);
 164 }
 165
 166 static void trace_argv_vprintf_fl(const char *file, int line,
 167                                   const char **argv, const char *format,
 168                                   va_list ap)
 169 {
 170         struct strbuf buf = STRBUF_INIT;
 171
 172         if (!prepare_trace_line(file, line, NULL, &buf))
 173                 return;
 174
 175         strbuf_vaddf(&buf, format, ap);
 176
 177         sq_quote_argv(&buf, argv, 0);
 178         print_trace_line(NULL, &buf);
 179 }
 180
 181 void trace_strbuf_fl(const char *file, int line, struct trace_key *key,
 182                      const struct strbuf *data)
 183 {
 184         struct strbuf buf = STRBUF_INIT;
 185
 186         if (!prepare_trace_line(file, line, key, &buf))
 187                 return;
 188
 189         strbuf_addbuf(&buf, data);
 190         print_trace_line(key, &buf);
 191 }
 192
 193 static struct trace_key trace_perf_key = TRACE_KEY_INIT(PERFORMANCE);
 194
 195 static void trace_performance_vprintf_fl(const char *file, int line,
 196                                          uint64_t nanos, const char *format,
 197                                          va_list ap)
 198 {
 199         struct strbuf buf = STRBUF_INIT;
 200
 201         if (!prepare_trace_line(file, line, &trace_perf_key, &buf))
 202                 return;
 203
 204         strbuf_addf(&buf, "performance: %.9f s", (double) nanos / 1000000000);
 205
 206         if (format && *format) {
 207                 strbuf_addstr(&buf, ": ");
 208                 strbuf_vaddf(&buf, format, ap);
 209         }
 210
 211         print_trace_line(&trace_perf_key, &buf);
 212 }
 213
 214 #ifndef HAVE_VARIADIC_MACROS
 215
 216 void trace_printf(const char *format, ...)
 217 {
 218         va_list ap;
 219         va_start(ap, format);
 220         trace_vprintf_fl(NULL, 0, NULL, format, ap);
 221         va_end(ap);
 222 }
 223
 224 void trace_printf_key(struct trace_key *key, const char *format, ...)
 225 {
 226         va_list ap;
 227         va_start(ap, format);
 228         trace_vprintf_fl(NULL, 0, key, format, ap);
 229         va_end(ap);
 230 }
 231
 232 void trace_argv_printf(const char **argv, const char *format, ...)
 233 {
 234         va_list ap;
 235         va_start(ap, format);
 236         trace_argv_vprintf_fl(NULL, 0, argv, format, ap);
 237         va_end(ap);
 238 }
 239
 240 void trace_strbuf(struct trace_key *key, const struct strbuf *data)
 241 {
 242         trace_strbuf_fl(NULL, 0, key, data);
 243 }
 244
 245 void trace_performance(uint64_t nanos, const char *format, ...)
 246 {
 247         va_list ap;
 248         va_start(ap, format);
 249         trace_performance_vprintf_fl(NULL, 0, nanos, format, ap);
 250         va_end(ap);
 251 }
 252
 253 void trace_performance_since(uint64_t start, const char *format, ...)
 254 {
 255         va_list ap;
 256         va_start(ap, format);
 257         trace_performance_vprintf_fl(NULL, 0, getnanotime() - start,
 258                                      format, ap);
 259         va_end(ap);
 260 }
 261
 262 #else
 263
 264 void trace_printf_key_fl(const char *file, int line, struct trace_key *key,
 265                          const char *format, ...)
 266 {
 267         va_list ap;
 268         va_start(ap, format);
 269         trace_vprintf_fl(file, line, key, format, ap);
 270         va_end(ap);
 271 }
 272
 273 void trace_argv_printf_fl(const char *file, int line, const char **argv,
 274                           const char *format, ...)
 275 {
 276         va_list ap;
 277         va_start(ap, format);
 278         trace_argv_vprintf_fl(file, line, argv, format, ap);
 279         va_end(ap);
 280 }
 281
 282 void trace_performance_fl(const char *file, int line, uint64_t nanos,
 283                               const char *format, ...)
 284 {
 285         va_list ap;
 286         va_start(ap, format);
 287         trace_performance_vprintf_fl(file, line, nanos, format, ap);
 288         va_end(ap);
 289 }
 290
 291 #endif /* HAVE_VARIADIC_MACROS */
 292
 293
 294 static const char *quote_crnl(const char *path)
 295 {
 296         static struct strbuf new_path = STRBUF_INIT;
 297
 298         if (!path)
 299                 return NULL;
 300
 301         strbuf_reset(&new_path);
 302
 303         while (*path) {
 304                 switch (*path) {
 305                 case '\\': strbuf_addstr(&new_path, "\\\\"); break;
 306                 case '\n': strbuf_addstr(&new_path, "\\n"); break;
 307                 case '\r': strbuf_addstr(&new_path, "\\r"); break;
 308                 default:
 309                         strbuf_addch(&new_path, *path);
 310                 }
 311                 path++;
 312         }
 313         return new_path.buf;
 314 }
 315
 316 /* FIXME: move prefix to startup_info struct and get rid of this arg */
 317 void trace_repo_setup(const char *prefix)
 318 {
 319         static struct trace_key key = TRACE_KEY_INIT(SETUP);
 320         const char *git_work_tree;
 321         char *cwd;
 322
 323         if (!trace_want(&key))
 324                 return;
 325
 326         cwd = xgetcwd();
 327
 328         if (!(git_work_tree = get_git_work_tree()))
 329                 git_work_tree = "(null)";
 330
 331         if (!prefix)
 332                 prefix = "(null)";
 333
 334         trace_printf_key(&key, "setup: git_dir: %s\n", quote_crnl(get_git_dir()));
 335         trace_printf_key(&key, "setup: git_common_dir: %s\n", quote_crnl(get_git_common_dir()));
 336         trace_printf_key(&key, "setup: worktree: %s\n", quote_crnl(git_work_tree));
 337         trace_printf_key(&key, "setup: cwd: %s\n", quote_crnl(cwd));
 338         trace_printf_key(&key, "setup: prefix: %s\n", quote_crnl(prefix));
 339
 340         free(cwd);
 341 }
 342
 343 int trace_want(struct trace_key *key)
 344 {
 345         return !!get_trace_fd(key);
 346 }
 347
 348 #if defined(HAVE_CLOCK_GETTIME) && defined(HAVE_CLOCK_MONOTONIC)
 349
 350 static inline uint64_t highres_nanos(void)
 351 {
 352         struct timespec ts;
 353         if (clock_gettime(CLOCK_MONOTONIC, &ts))
 354                 return 0;
 355         return (uint64_t) ts.tv_sec * 1000000000 + ts.tv_nsec;
 356 }
 357
 358 #elif defined (GIT_WINDOWS_NATIVE)
 359
 360 static inline uint64_t highres_nanos(void)
 361 {
 362         static uint64_t high_ns, scaled_low_ns;
 363         static int scale;
 364         LARGE_INTEGER cnt;
 365
 366         if (!scale) {
 367                 if (!QueryPerformanceFrequency(&cnt))
 368                         return 0;
 369
 370                 /* high_ns = number of ns per cnt.HighPart */
 371                 high_ns = (1000000000LL << 32) / (uint64_t) cnt.QuadPart;
 372
 373                 /*
 374                  * Number of ns per cnt.LowPart is 10^9 / frequency (or
 375                  * high_ns >> 32). For maximum precision, we scale this factor
 376                  * so that it just fits within 32 bit (i.e. won't overflow if
 377                  * multiplied with cnt.LowPart).
 378                  */
 379                 scaled_low_ns = high_ns;
 380                 scale = 32;
 381                 while (scaled_low_ns >= 0x100000000LL) {
 382                         scaled_low_ns >>= 1;
 383                         scale--;
 384                 }
 385         }
 386
 387         /* if QPF worked on initialization, we expect QPC to work as well */
 388         QueryPerformanceCounter(&cnt);
 389
 390         return (high_ns * cnt.HighPart) +
 391                ((scaled_low_ns * cnt.LowPart) >> scale);
 392 }
 393
 394 #else
 395 # define highres_nanos() 0
 396 #endif
 397
 398 static inline uint64_t gettimeofday_nanos(void)
 399 {
 400         struct timeval tv;
 401         gettimeofday(&tv, NULL);
 402         return (uint64_t) tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
 403 }
 404
 405 /*
 406  * Returns nanoseconds since the epoch (01/01/1970), for performance tracing
 407  * (i.e. favoring high precision over wall clock time accuracy).
 408  */
 409 uint64_t getnanotime(void)
 410 {
 411         static uint64_t offset;
 412         if (offset > 1) {
 413                 /* initialization succeeded, return offset + high res time */
 414                 return offset + highres_nanos();
 415         } else if (offset == 1) {
 416                 /* initialization failed, fall back to gettimeofday */
 417                 return gettimeofday_nanos();
 418         } else {
 419                 /* initialize offset if high resolution timer works */
 420                 uint64_t now = gettimeofday_nanos();
 421                 uint64_t highres = highres_nanos();
 422                 if (highres)
 423                         offset = now - highres;
 424                 else
 425                         offset = 1;
 426                 return now;
 427         }
 428 }
 429
 430 static uint64_t command_start_time;
 431 static struct strbuf command_line = STRBUF_INIT;
 432
 433 static void print_command_performance_atexit(void)
 434 {
 435         trace_performance_since(command_start_time, "git command:%s",
 436                                 command_line.buf);
 437 }
 438
 439 void trace_command_performance(const char **argv)
 440 {
 441         if (!trace_want(&trace_perf_key))
 442                 return;
 443
 444         if (!command_start_time)
 445                 atexit(print_command_performance_atexit);
 446
 447         strbuf_reset(&command_line);
 448         sq_quote_argv(&command_line, argv, 0);
 449         command_start_time = getnanotime();
 450 }