6a77e4df037cfe48694d5b686bcc291243cb8dd3
   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/*
  29 * "Normalize" a key argument by converting NULL to our trace_default,
  30 * and otherwise passing through the value. All caller-facing functions
  31 * should normalize their inputs in this way, though most get it
  32 * for free by calling get_trace_fd() (directly or indirectly).
  33 */
  34static void normalize_trace_key(struct trace_key **key)
  35{
  36        static struct trace_key trace_default = { "GIT_TRACE" };
  37        if (!*key)
  38                *key = &trace_default;
  39}
  40
  41/* Get a trace file descriptor from "key" env variable. */
  42static int get_trace_fd(struct trace_key *key)
  43{
  44        const char *trace;
  45
  46        normalize_trace_key(&key);
  47
  48        /* don't open twice */
  49        if (key->initialized)
  50                return key->fd;
  51
  52        trace = getenv(key->key);
  53
  54        if (!trace || !strcmp(trace, "") ||
  55            !strcmp(trace, "0") || !strcasecmp(trace, "false"))
  56                key->fd = 0;
  57        else if (!strcmp(trace, "1") || !strcasecmp(trace, "true"))
  58                key->fd = STDERR_FILENO;
  59        else if (strlen(trace) == 1 && isdigit(*trace))
  60                key->fd = atoi(trace);
  61        else if (is_absolute_path(trace)) {
  62                int fd = open(trace, O_WRONLY | O_APPEND | O_CREAT, 0666);
  63                if (fd == -1) {
  64                        warning("Could not open '%s' for tracing: %s\n"
  65                                "Defaulting to tracing on stderr...",
  66                                trace, strerror(errno));
  67                        key->fd = STDERR_FILENO;
  68                } else {
  69                        key->fd = fd;
  70                        key->need_close = 1;
  71                }
  72        } else {
  73                warning("What does '%s' for %s mean?\n"
  74                        "If you want to trace into a file, then please set "
  75                        "%s to an absolute pathname (starting with /).\n"
  76                        "Defaulting to tracing on stderr...",
  77                        trace, key->key, key->key);
  78                key->fd = STDERR_FILENO;
  79        }
  80
  81        key->initialized = 1;
  82        return key->fd;
  83}
  84
  85void trace_disable(struct trace_key *key)
  86{
  87        normalize_trace_key(&key);
  88
  89        if (key->need_close)
  90                close(key->fd);
  91        key->fd = 0;
  92        key->initialized = 1;
  93        key->need_close = 0;
  94}
  95
  96static const char err_msg[] = "Could not trace into fd given by "
  97        "GIT_TRACE environment variable";
  98
  99static int prepare_trace_line(const char *file, int line,
 100                              struct trace_key *key, struct strbuf *buf)
 101{
 102        static struct trace_key trace_bare = TRACE_KEY_INIT(BARE);
 103        struct timeval tv;
 104        struct tm tm;
 105        time_t secs;
 106
 107        if (!trace_want(key))
 108                return 0;
 109
 110        set_try_to_free_routine(NULL);  /* is never reset */
 111
 112        /* unit tests may want to disable additional trace output */
 113        if (trace_want(&trace_bare))
 114                return 1;
 115
 116        /* print current timestamp */
 117        gettimeofday(&tv, NULL);
 118        secs = tv.tv_sec;
 119        localtime_r(&secs, &tm);
 120        strbuf_addf(buf, "%02d:%02d:%02d.%06ld ", tm.tm_hour, tm.tm_min,
 121                    tm.tm_sec, (long) tv.tv_usec);
 122
 123#ifdef HAVE_VARIADIC_MACROS
 124        /* print file:line */
 125        strbuf_addf(buf, "%s:%d ", file, line);
 126        /* align trace output (column 40 catches most files names in git) */
 127        while (buf->len < 40)
 128                strbuf_addch(buf, ' ');
 129#endif
 130
 131        return 1;
 132}
 133
 134static void trace_write(struct trace_key *key, const void *buf, unsigned len)
 135{
 136        if (write_in_full(get_trace_fd(key), buf, len) < 0)
 137                warning("%s: write error (%s)", err_msg, strerror(errno));
 138}
 139
 140void trace_verbatim(struct trace_key *key, const void *buf, unsigned len)
 141{
 142        if (!trace_want(key))
 143                return;
 144        trace_write(key, buf, len);
 145}
 146
 147static void print_trace_line(struct trace_key *key, struct strbuf *buf)
 148{
 149        strbuf_complete_line(buf);
 150        trace_write(key, buf->buf, buf->len);
 151        strbuf_release(buf);
 152}
 153
 154static void trace_vprintf_fl(const char *file, int line, struct trace_key *key,
 155                             const char *format, va_list ap)
 156{
 157        struct strbuf buf = STRBUF_INIT;
 158
 159        if (!prepare_trace_line(file, line, key, &buf))
 160                return;
 161
 162        strbuf_vaddf(&buf, format, ap);
 163        print_trace_line(key, &buf);
 164}
 165
 166static void trace_argv_vprintf_fl(const char *file, int line,
 167                                  const char **argv, const char *format,
 168                                  va_list ap)
 169{
 170        struct strbuf buf = STRBUF_INIT;
 171
 172        if (!prepare_trace_line(file, line, NULL, &buf))
 173                return;
 174
 175        strbuf_vaddf(&buf, format, ap);
 176
 177        sq_quote_argv(&buf, argv, 0);
 178        print_trace_line(NULL, &buf);
 179}
 180
 181void trace_strbuf_fl(const char *file, int line, struct trace_key *key,
 182                     const struct strbuf *data)
 183{
 184        struct strbuf buf = STRBUF_INIT;
 185
 186        if (!prepare_trace_line(file, line, key, &buf))
 187                return;
 188
 189        strbuf_addbuf(&buf, data);
 190        print_trace_line(key, &buf);
 191}
 192
 193static struct trace_key trace_perf_key = TRACE_KEY_INIT(PERFORMANCE);
 194
 195static void trace_performance_vprintf_fl(const char *file, int line,
 196                                         uint64_t nanos, const char *format,
 197                                         va_list ap)
 198{
 199        struct strbuf buf = STRBUF_INIT;
 200
 201        if (!prepare_trace_line(file, line, &trace_perf_key, &buf))
 202                return;
 203
 204        strbuf_addf(&buf, "performance: %.9f s", (double) nanos / 1000000000);
 205
 206        if (format && *format) {
 207                strbuf_addstr(&buf, ": ");
 208                strbuf_vaddf(&buf, format, ap);
 209        }
 210
 211        print_trace_line(&trace_perf_key, &buf);
 212}
 213
 214#ifndef HAVE_VARIADIC_MACROS
 215
 216void trace_printf(const char *format, ...)
 217{
 218        va_list ap;
 219        va_start(ap, format);
 220        trace_vprintf_fl(NULL, 0, NULL, format, ap);
 221        va_end(ap);
 222}
 223
 224void trace_printf_key(struct trace_key *key, const char *format, ...)
 225{
 226        va_list ap;
 227        va_start(ap, format);
 228        trace_vprintf_fl(NULL, 0, key, format, ap);
 229        va_end(ap);
 230}
 231
 232void trace_argv_printf(const char **argv, const char *format, ...)
 233{
 234        va_list ap;
 235        va_start(ap, format);
 236        trace_argv_vprintf_fl(NULL, 0, argv, format, ap);
 237        va_end(ap);
 238}
 239
 240void trace_strbuf(struct trace_key *key, const struct strbuf *data)
 241{
 242        trace_strbuf_fl(NULL, 0, key, data);
 243}
 244
 245void trace_performance(uint64_t nanos, const char *format, ...)
 246{
 247        va_list ap;
 248        va_start(ap, format);
 249        trace_performance_vprintf_fl(NULL, 0, nanos, format, ap);
 250        va_end(ap);
 251}
 252
 253void trace_performance_since(uint64_t start, const char *format, ...)
 254{
 255        va_list ap;
 256        va_start(ap, format);
 257        trace_performance_vprintf_fl(NULL, 0, getnanotime() - start,
 258                                     format, ap);
 259        va_end(ap);
 260}
 261
 262#else
 263
 264void trace_printf_key_fl(const char *file, int line, struct trace_key *key,
 265                         const char *format, ...)
 266{
 267        va_list ap;
 268        va_start(ap, format);
 269        trace_vprintf_fl(file, line, key, format, ap);
 270        va_end(ap);
 271}
 272
 273void trace_argv_printf_fl(const char *file, int line, const char **argv,
 274                          const char *format, ...)
 275{
 276        va_list ap;
 277        va_start(ap, format);
 278        trace_argv_vprintf_fl(file, line, argv, format, ap);
 279        va_end(ap);
 280}
 281
 282void trace_performance_fl(const char *file, int line, uint64_t nanos,
 283                              const char *format, ...)
 284{
 285        va_list ap;
 286        va_start(ap, format);
 287        trace_performance_vprintf_fl(file, line, nanos, format, ap);
 288        va_end(ap);
 289}
 290
 291#endif /* HAVE_VARIADIC_MACROS */
 292
 293
 294static const char *quote_crnl(const char *path)
 295{
 296        static struct strbuf new_path = STRBUF_INIT;
 297
 298        if (!path)
 299                return NULL;
 300
 301        strbuf_reset(&new_path);
 302
 303        while (*path) {
 304                switch (*path) {
 305                case '\\': strbuf_addstr(&new_path, "\\\\"); break;
 306                case '\n': strbuf_addstr(&new_path, "\\n"); break;
 307                case '\r': strbuf_addstr(&new_path, "\\r"); break;
 308                default:
 309                        strbuf_addch(&new_path, *path);
 310                }
 311                path++;
 312        }
 313        return new_path.buf;
 314}
 315
 316/* FIXME: move prefix to startup_info struct and get rid of this arg */
 317void trace_repo_setup(const char *prefix)
 318{
 319        static struct trace_key key = TRACE_KEY_INIT(SETUP);
 320        const char *git_work_tree;
 321        char *cwd;
 322
 323        if (!trace_want(&key))
 324                return;
 325
 326        cwd = xgetcwd();
 327
 328        if (!(git_work_tree = get_git_work_tree()))
 329                git_work_tree = "(null)";
 330
 331        if (!prefix)
 332                prefix = "(null)";
 333
 334        trace_printf_key(&key, "setup: git_dir: %s\n", quote_crnl(get_git_dir()));
 335        trace_printf_key(&key, "setup: git_common_dir: %s\n", quote_crnl(get_git_common_dir()));
 336        trace_printf_key(&key, "setup: worktree: %s\n", quote_crnl(git_work_tree));
 337        trace_printf_key(&key, "setup: cwd: %s\n", quote_crnl(cwd));
 338        trace_printf_key(&key, "setup: prefix: %s\n", quote_crnl(prefix));
 339
 340        free(cwd);
 341}
 342
 343int trace_want(struct trace_key *key)
 344{
 345        return !!get_trace_fd(key);
 346}
 347
 348#if defined(HAVE_CLOCK_GETTIME) && defined(HAVE_CLOCK_MONOTONIC)
 349
 350static inline uint64_t highres_nanos(void)
 351{
 352        struct timespec ts;
 353        if (clock_gettime(CLOCK_MONOTONIC, &ts))
 354                return 0;
 355        return (uint64_t) ts.tv_sec * 1000000000 + ts.tv_nsec;
 356}
 357
 358#elif defined (GIT_WINDOWS_NATIVE)
 359
 360static inline uint64_t highres_nanos(void)
 361{
 362        static uint64_t high_ns, scaled_low_ns;
 363        static int scale;
 364        LARGE_INTEGER cnt;
 365
 366        if (!scale) {
 367                if (!QueryPerformanceFrequency(&cnt))
 368                        return 0;
 369
 370                /* high_ns = number of ns per cnt.HighPart */
 371                high_ns = (1000000000LL << 32) / (uint64_t) cnt.QuadPart;
 372
 373                /*
 374                 * Number of ns per cnt.LowPart is 10^9 / frequency (or
 375                 * high_ns >> 32). For maximum precision, we scale this factor
 376                 * so that it just fits within 32 bit (i.e. won't overflow if
 377                 * multiplied with cnt.LowPart).
 378                 */
 379                scaled_low_ns = high_ns;
 380                scale = 32;
 381                while (scaled_low_ns >= 0x100000000LL) {
 382                        scaled_low_ns >>= 1;
 383                        scale--;
 384                }
 385        }
 386
 387        /* if QPF worked on initialization, we expect QPC to work as well */
 388        QueryPerformanceCounter(&cnt);
 389
 390        return (high_ns * cnt.HighPart) +
 391               ((scaled_low_ns * cnt.LowPart) >> scale);
 392}
 393
 394#else
 395# define highres_nanos() 0
 396#endif
 397
 398static inline uint64_t gettimeofday_nanos(void)
 399{
 400        struct timeval tv;
 401        gettimeofday(&tv, NULL);
 402        return (uint64_t) tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
 403}
 404
 405/*
 406 * Returns nanoseconds since the epoch (01/01/1970), for performance tracing
 407 * (i.e. favoring high precision over wall clock time accuracy).
 408 */
 409uint64_t getnanotime(void)
 410{
 411        static uint64_t offset;
 412        if (offset > 1) {
 413                /* initialization succeeded, return offset + high res time */
 414                return offset + highres_nanos();
 415        } else if (offset == 1) {
 416                /* initialization failed, fall back to gettimeofday */
 417                return gettimeofday_nanos();
 418        } else {
 419                /* initialize offset if high resolution timer works */
 420                uint64_t now = gettimeofday_nanos();
 421                uint64_t highres = highres_nanos();
 422                if (highres)
 423                        offset = now - highres;
 424                else
 425                        offset = 1;
 426                return now;
 427        }
 428}
 429
 430static uint64_t command_start_time;
 431static struct strbuf command_line = STRBUF_INIT;
 432
 433static void print_command_performance_atexit(void)
 434{
 435        trace_performance_since(command_start_time, "git command:%s",
 436                                command_line.buf);
 437}
 438
 439void trace_command_performance(const char **argv)
 440{
 441        if (!trace_want(&trace_perf_key))
 442                return;
 443
 444        if (!command_start_time)
 445                atexit(print_command_performance_atexit);
 446
 447        strbuf_reset(&command_line);
 448        sq_quote_argv(&command_line, argv, 0);
 449        command_start_time = getnanotime();
 450}