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