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