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