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 static void print_trace_line(struct trace_key *key, struct strbuf *buf)
 124 {
 125         strbuf_complete_line(buf);
 126
 127         write_or_whine_pipe(get_trace_fd(key), buf->buf, buf->len, err_msg);
 128         strbuf_release(buf);
 129 }
 130
 131 static void trace_vprintf_fl(const char *file, int line, struct trace_key *key,
 132                              const char *format, va_list ap)
 133 {
 134         struct strbuf buf = STRBUF_INIT;
 135
 136         if (!prepare_trace_line(file, line, key, &buf))
 137                 return;
 138
 139         strbuf_vaddf(&buf, format, ap);
 140         print_trace_line(key, &buf);
 141 }
 142
 143 static void trace_argv_vprintf_fl(const char *file, int line,
 144                                   const char **argv, const char *format,
 145                                   va_list ap)
 146 {
 147         struct strbuf buf = STRBUF_INIT;
 148
 149         if (!prepare_trace_line(file, line, NULL, &buf))
 150                 return;
 151
 152         strbuf_vaddf(&buf, format, ap);
 153
 154         sq_quote_argv(&buf, argv, 0);
 155         print_trace_line(NULL, &buf);
 156 }
 157
 158 void trace_strbuf_fl(const char *file, int line, struct trace_key *key,
 159                      const struct strbuf *data)
 160 {
 161         struct strbuf buf = STRBUF_INIT;
 162
 163         if (!prepare_trace_line(file, line, key, &buf))
 164                 return;
 165
 166         strbuf_addbuf(&buf, data);
 167         print_trace_line(key, &buf);
 168 }
 169
 170 static struct trace_key trace_perf_key = TRACE_KEY_INIT(PERFORMANCE);
 171
 172 static void trace_performance_vprintf_fl(const char *file, int line,
 173                                          uint64_t nanos, const char *format,
 174                                          va_list ap)
 175 {
 176         struct strbuf buf = STRBUF_INIT;
 177
 178         if (!prepare_trace_line(file, line, &trace_perf_key, &buf))
 179                 return;
 180
 181         strbuf_addf(&buf, "performance: %.9f s", (double) nanos / 1000000000);
 182
 183         if (format && *format) {
 184                 strbuf_addstr(&buf, ": ");
 185                 strbuf_vaddf(&buf, format, ap);
 186         }
 187
 188         print_trace_line(&trace_perf_key, &buf);
 189 }
 190
 191 #ifndef HAVE_VARIADIC_MACROS
 192
 193 void trace_printf(const char *format, ...)
 194 {
 195         va_list ap;
 196         va_start(ap, format);
 197         trace_vprintf_fl(NULL, 0, NULL, format, ap);
 198         va_end(ap);
 199 }
 200
 201 void trace_printf_key(struct trace_key *key, const char *format, ...)
 202 {
 203         va_list ap;
 204         va_start(ap, format);
 205         trace_vprintf_fl(NULL, 0, key, format, ap);
 206         va_end(ap);
 207 }
 208
 209 void trace_argv_printf(const char **argv, const char *format, ...)
 210 {
 211         va_list ap;
 212         va_start(ap, format);
 213         trace_argv_vprintf_fl(NULL, 0, argv, format, ap);
 214         va_end(ap);
 215 }
 216
 217 void trace_strbuf(struct trace_key *key, const struct strbuf *data)
 218 {
 219         trace_strbuf_fl(NULL, 0, key, data);
 220 }
 221
 222 void trace_performance(uint64_t nanos, const char *format, ...)
 223 {
 224         va_list ap;
 225         va_start(ap, format);
 226         trace_performance_vprintf_fl(NULL, 0, nanos, format, ap);
 227         va_end(ap);
 228 }
 229
 230 void trace_performance_since(uint64_t start, const char *format, ...)
 231 {
 232         va_list ap;
 233         va_start(ap, format);
 234         trace_performance_vprintf_fl(NULL, 0, getnanotime() - start,
 235                                      format, ap);
 236         va_end(ap);
 237 }
 238
 239 #else
 240
 241 void trace_printf_key_fl(const char *file, int line, struct trace_key *key,
 242                          const char *format, ...)
 243 {
 244         va_list ap;
 245         va_start(ap, format);
 246         trace_vprintf_fl(file, line, key, format, ap);
 247         va_end(ap);
 248 }
 249
 250 void trace_argv_printf_fl(const char *file, int line, const char **argv,
 251                           const char *format, ...)
 252 {
 253         va_list ap;
 254         va_start(ap, format);
 255         trace_argv_vprintf_fl(file, line, argv, format, ap);
 256         va_end(ap);
 257 }
 258
 259 void trace_performance_fl(const char *file, int line, uint64_t nanos,
 260                               const char *format, ...)
 261 {
 262         va_list ap;
 263         va_start(ap, format);
 264         trace_performance_vprintf_fl(file, line, nanos, format, ap);
 265         va_end(ap);
 266 }
 267
 268 #endif /* HAVE_VARIADIC_MACROS */
 269
 270
 271 static const char *quote_crnl(const char *path)
 272 {
 273         static char new_path[PATH_MAX];
 274         const char *p2 = path;
 275         char *p1 = new_path;
 276
 277         if (!path)
 278                 return NULL;
 279
 280         while (*p2) {
 281                 switch (*p2) {
 282                 case '\\': *p1++ = '\\'; *p1++ = '\\'; break;
 283                 case '\n': *p1++ = '\\'; *p1++ = 'n'; break;
 284                 case '\r': *p1++ = '\\'; *p1++ = 'r'; break;
 285                 default:
 286                         *p1++ = *p2;
 287                 }
 288                 p2++;
 289         }
 290         *p1 = '\0';
 291         return new_path;
 292 }
 293
 294 /* FIXME: move prefix to startup_info struct and get rid of this arg */
 295 void trace_repo_setup(const char *prefix)
 296 {
 297         static struct trace_key key = TRACE_KEY_INIT(SETUP);
 298         const char *git_work_tree;
 299         char *cwd;
 300
 301         if (!trace_want(&key))
 302                 return;
 303
 304         cwd = xgetcwd();
 305
 306         if (!(git_work_tree = get_git_work_tree()))
 307                 git_work_tree = "(null)";
 308
 309         if (!prefix)
 310                 prefix = "(null)";
 311
 312         trace_printf_key(&key, "setup: git_dir: %s\n", quote_crnl(get_git_dir()));
 313         trace_printf_key(&key, "setup: worktree: %s\n", quote_crnl(git_work_tree));
 314         trace_printf_key(&key, "setup: cwd: %s\n", quote_crnl(cwd));
 315         trace_printf_key(&key, "setup: prefix: %s\n", quote_crnl(prefix));
 316
 317         free(cwd);
 318 }
 319
 320 int trace_want(struct trace_key *key)
 321 {
 322         return !!get_trace_fd(key);
 323 }
 324
 325 #if defined(HAVE_CLOCK_GETTIME) && defined(HAVE_CLOCK_MONOTONIC)
 326
 327 static inline uint64_t highres_nanos(void)
 328 {
 329         struct timespec ts;
 330         if (clock_gettime(CLOCK_MONOTONIC, &ts))
 331                 return 0;
 332         return (uint64_t) ts.tv_sec * 1000000000 + ts.tv_nsec;
 333 }
 334
 335 #elif defined (GIT_WINDOWS_NATIVE)
 336
 337 static inline uint64_t highres_nanos(void)
 338 {
 339         static uint64_t high_ns, scaled_low_ns;
 340         static int scale;
 341         LARGE_INTEGER cnt;
 342
 343         if (!scale) {
 344                 if (!QueryPerformanceFrequency(&cnt))
 345                         return 0;
 346
 347                 /* high_ns = number of ns per cnt.HighPart */
 348                 high_ns = (1000000000LL << 32) / (uint64_t) cnt.QuadPart;
 349
 350                 /*
 351                  * Number of ns per cnt.LowPart is 10^9 / frequency (or
 352                  * high_ns >> 32). For maximum precision, we scale this factor
 353                  * so that it just fits within 32 bit (i.e. won't overflow if
 354                  * multiplied with cnt.LowPart).
 355                  */
 356                 scaled_low_ns = high_ns;
 357                 scale = 32;
 358                 while (scaled_low_ns >= 0x100000000LL) {
 359                         scaled_low_ns >>= 1;
 360                         scale--;
 361                 }
 362         }
 363
 364         /* if QPF worked on initialization, we expect QPC to work as well */
 365         QueryPerformanceCounter(&cnt);
 366
 367         return (high_ns * cnt.HighPart) +
 368                ((scaled_low_ns * cnt.LowPart) >> scale);
 369 }
 370
 371 #else
 372 # define highres_nanos() 0
 373 #endif
 374
 375 static inline uint64_t gettimeofday_nanos(void)
 376 {
 377         struct timeval tv;
 378         gettimeofday(&tv, NULL);
 379         return (uint64_t) tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
 380 }
 381
 382 /*
 383  * Returns nanoseconds since the epoch (01/01/1970), for performance tracing
 384  * (i.e. favoring high precision over wall clock time accuracy).
 385  */
 386 uint64_t getnanotime(void)
 387 {
 388         static uint64_t offset;
 389         if (offset > 1) {
 390                 /* initialization succeeded, return offset + high res time */
 391                 return offset + highres_nanos();
 392         } else if (offset == 1) {
 393                 /* initialization failed, fall back to gettimeofday */
 394                 return gettimeofday_nanos();
 395         } else {
 396                 /* initialize offset if high resolution timer works */
 397                 uint64_t now = gettimeofday_nanos();
 398                 uint64_t highres = highres_nanos();
 399                 if (highres)
 400                         offset = now - highres;
 401                 else
 402                         offset = 1;
 403                 return now;
 404         }
 405 }
 406
 407 static uint64_t command_start_time;
 408 static struct strbuf command_line = STRBUF_INIT;
 409
 410 static void print_command_performance_atexit(void)
 411 {
 412         trace_performance_since(command_start_time, "git command:%s",
 413                                 command_line.buf);
 414 }
 415
 416 void trace_command_performance(const char **argv)
 417 {
 418         if (!trace_want(&trace_perf_key))
 419                 return;
 420
 421         if (!command_start_time)
 422                 atexit(print_command_performance_atexit);
 423
 424         strbuf_reset(&command_line);
 425         sq_quote_argv(&command_line, argv, 0);
 426         command_start_time = getnanotime();
 427 }