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         /* append newline if missing */
 126         if (buf->len && buf->buf[buf->len - 1] != '\n')
 127                 strbuf_addch(buf, '\n');
 128
 129         write_or_whine_pipe(get_trace_fd(key), buf->buf, buf->len, err_msg);
 130         strbuf_release(buf);
 131 }
 132
 133 static void trace_vprintf_fl(const char *file, int line, struct trace_key *key,
 134                              const char *format, va_list ap)
 135 {
 136         struct strbuf buf = STRBUF_INIT;
 137
 138         if (!prepare_trace_line(file, line, key, &buf))
 139                 return;
 140
 141         strbuf_vaddf(&buf, format, ap);
 142         print_trace_line(key, &buf);
 143 }
 144
 145 static void trace_argv_vprintf_fl(const char *file, int line,
 146                                   const char **argv, const char *format,
 147                                   va_list ap)
 148 {
 149         struct strbuf buf = STRBUF_INIT;
 150
 151         if (!prepare_trace_line(file, line, NULL, &buf))
 152                 return;
 153
 154         strbuf_vaddf(&buf, format, ap);
 155
 156         sq_quote_argv(&buf, argv, 0);
 157         print_trace_line(NULL, &buf);
 158 }
 159
 160 void trace_strbuf_fl(const char *file, int line, struct trace_key *key,
 161                      const struct strbuf *data)
 162 {
 163         struct strbuf buf = STRBUF_INIT;
 164
 165         if (!prepare_trace_line(file, line, key, &buf))
 166                 return;
 167
 168         strbuf_addbuf(&buf, data);
 169         print_trace_line(key, &buf);
 170 }
 171
 172 static struct trace_key trace_perf_key = TRACE_KEY_INIT(PERFORMANCE);
 173
 174 static void trace_performance_vprintf_fl(const char *file, int line,
 175                                          uint64_t nanos, const char *format,
 176                                          va_list ap)
 177 {
 178         struct strbuf buf = STRBUF_INIT;
 179
 180         if (!prepare_trace_line(file, line, &trace_perf_key, &buf))
 181                 return;
 182
 183         strbuf_addf(&buf, "performance: %.9f s", (double) nanos / 1000000000);
 184
 185         if (format && *format) {
 186                 strbuf_addstr(&buf, ": ");
 187                 strbuf_vaddf(&buf, format, ap);
 188         }
 189
 190         print_trace_line(&trace_perf_key, &buf);
 191 }
 192
 193 #ifndef HAVE_VARIADIC_MACROS
 194
 195 void trace_printf(const char *format, ...)
 196 {
 197         va_list ap;
 198         va_start(ap, format);
 199         trace_vprintf_fl(NULL, 0, NULL, format, ap);
 200         va_end(ap);
 201 }
 202
 203 void trace_printf_key(struct trace_key *key, const char *format, ...)
 204 {
 205         va_list ap;
 206         va_start(ap, format);
 207         trace_vprintf_fl(NULL, 0, key, format, ap);
 208         va_end(ap);
 209 }
 210
 211 void trace_argv_printf(const char **argv, const char *format, ...)
 212 {
 213         va_list ap;
 214         va_start(ap, format);
 215         trace_argv_vprintf_fl(NULL, 0, argv, format, ap);
 216         va_end(ap);
 217 }
 218
 219 void trace_strbuf(struct trace_key *key, const struct strbuf *data)
 220 {
 221         trace_strbuf_fl(NULL, 0, key, data);
 222 }
 223
 224 void trace_performance(uint64_t nanos, const char *format, ...)
 225 {
 226         va_list ap;
 227         va_start(ap, format);
 228         trace_performance_vprintf_fl(NULL, 0, nanos, format, ap);
 229         va_end(ap);
 230 }
 231
 232 void trace_performance_since(uint64_t start, const char *format, ...)
 233 {
 234         va_list ap;
 235         va_start(ap, format);
 236         trace_performance_vprintf_fl(NULL, 0, getnanotime() - start,
 237                                      format, ap);
 238         va_end(ap);
 239 }
 240
 241 #else
 242
 243 void trace_printf_key_fl(const char *file, int line, struct trace_key *key,
 244                          const char *format, ...)
 245 {
 246         va_list ap;
 247         va_start(ap, format);
 248         trace_vprintf_fl(file, line, key, format, ap);
 249         va_end(ap);
 250 }
 251
 252 void trace_argv_printf_fl(const char *file, int line, const char **argv,
 253                           const char *format, ...)
 254 {
 255         va_list ap;
 256         va_start(ap, format);
 257         trace_argv_vprintf_fl(file, line, argv, format, ap);
 258         va_end(ap);
 259 }
 260
 261 void trace_performance_fl(const char *file, int line, uint64_t nanos,
 262                               const char *format, ...)
 263 {
 264         va_list ap;
 265         va_start(ap, format);
 266         trace_performance_vprintf_fl(file, line, nanos, format, ap);
 267         va_end(ap);
 268 }
 269
 270 #endif /* HAVE_VARIADIC_MACROS */
 271
 272
 273 static const char *quote_crnl(const char *path)
 274 {
 275         static char new_path[PATH_MAX];
 276         const char *p2 = path;
 277         char *p1 = new_path;
 278
 279         if (!path)
 280                 return NULL;
 281
 282         while (*p2) {
 283                 switch (*p2) {
 284                 case '\\': *p1++ = '\\'; *p1++ = '\\'; break;
 285                 case '\n': *p1++ = '\\'; *p1++ = 'n'; break;
 286                 case '\r': *p1++ = '\\'; *p1++ = 'r'; break;
 287                 default:
 288                         *p1++ = *p2;
 289                 }
 290                 p2++;
 291         }
 292         *p1 = '\0';
 293         return new_path;
 294 }
 295
 296 /* FIXME: move prefix to startup_info struct and get rid of this arg */
 297 void trace_repo_setup(const char *prefix)
 298 {
 299         static struct trace_key key = TRACE_KEY_INIT(SETUP);
 300         const char *git_work_tree;
 301         char *cwd;
 302
 303         if (!trace_want(&key))
 304                 return;
 305
 306         cwd = xgetcwd();
 307
 308         if (!(git_work_tree = get_git_work_tree()))
 309                 git_work_tree = "(null)";
 310
 311         if (!prefix)
 312                 prefix = "(null)";
 313
 314         trace_printf_key(&key, "setup: git_dir: %s\n", quote_crnl(get_git_dir()));
 315         trace_printf_key(&key, "setup: worktree: %s\n", quote_crnl(git_work_tree));
 316         trace_printf_key(&key, "setup: cwd: %s\n", quote_crnl(cwd));
 317         trace_printf_key(&key, "setup: prefix: %s\n", quote_crnl(prefix));
 318
 319         free(cwd);
 320 }
 321
 322 int trace_want(struct trace_key *key)
 323 {
 324         return !!get_trace_fd(key);
 325 }
 326
 327 #ifdef HAVE_CLOCK_GETTIME
 328
 329 static inline uint64_t highres_nanos(void)
 330 {
 331         struct timespec ts;
 332         if (clock_gettime(CLOCK_MONOTONIC, &ts))
 333                 return 0;
 334         return (uint64_t) ts.tv_sec * 1000000000 + ts.tv_nsec;
 335 }
 336
 337 #elif defined (GIT_WINDOWS_NATIVE)
 338
 339 static inline uint64_t highres_nanos(void)
 340 {
 341         static uint64_t high_ns, scaled_low_ns;
 342         static int scale;
 343         LARGE_INTEGER cnt;
 344
 345         if (!scale) {
 346                 if (!QueryPerformanceFrequency(&cnt))
 347                         return 0;
 348
 349                 /* high_ns = number of ns per cnt.HighPart */
 350                 high_ns = (1000000000LL << 32) / (uint64_t) cnt.QuadPart;
 351
 352                 /*
 353                  * Number of ns per cnt.LowPart is 10^9 / frequency (or
 354                  * high_ns >> 32). For maximum precision, we scale this factor
 355                  * so that it just fits within 32 bit (i.e. won't overflow if
 356                  * multiplied with cnt.LowPart).
 357                  */
 358                 scaled_low_ns = high_ns;
 359                 scale = 32;
 360                 while (scaled_low_ns >= 0x100000000LL) {
 361                         scaled_low_ns >>= 1;
 362                         scale--;
 363                 }
 364         }
 365
 366         /* if QPF worked on initialization, we expect QPC to work as well */
 367         QueryPerformanceCounter(&cnt);
 368
 369         return (high_ns * cnt.HighPart) +
 370                ((scaled_low_ns * cnt.LowPart) >> scale);
 371 }
 372
 373 #else
 374 # define highres_nanos() 0
 375 #endif
 376
 377 static inline uint64_t gettimeofday_nanos(void)
 378 {
 379         struct timeval tv;
 380         gettimeofday(&tv, NULL);
 381         return (uint64_t) tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
 382 }
 383
 384 /*
 385  * Returns nanoseconds since the epoch (01/01/1970), for performance tracing
 386  * (i.e. favoring high precision over wall clock time accuracy).
 387  */
 388 uint64_t getnanotime(void)
 389 {
 390         static uint64_t offset;
 391         if (offset > 1) {
 392                 /* initialization succeeded, return offset + high res time */
 393                 return offset + highres_nanos();
 394         } else if (offset == 1) {
 395                 /* initialization failed, fall back to gettimeofday */
 396                 return gettimeofday_nanos();
 397         } else {
 398                 /* initialize offset if high resolution timer works */
 399                 uint64_t now = gettimeofday_nanos();
 400                 uint64_t highres = highres_nanos();
 401                 if (highres)
 402                         offset = now - highres;
 403                 else
 404                         offset = 1;
 405                 return now;
 406         }
 407 }
 408
 409 static uint64_t command_start_time;
 410 static struct strbuf command_line = STRBUF_INIT;
 411
 412 static void print_command_performance_atexit(void)
 413 {
 414         trace_performance_since(command_start_time, "git command:%s",
 415                                 command_line.buf);
 416 }
 417
 418 void trace_command_performance(const char **argv)
 419 {
 420         if (!trace_want(&trace_perf_key))
 421                 return;
 422
 423         if (!command_start_time)
 424                 atexit(print_command_performance_atexit);
 425
 426         strbuf_reset(&command_line);
 427         sq_quote_argv(&command_line, argv, 0);
 428         command_start_time = getnanotime();
 429 }