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