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 #ifndef HAVE_VARIADIC_MACROS
 173
 174 void trace_printf(const char *format, ...)
 175 {
 176         va_list ap;
 177         va_start(ap, format);
 178         trace_vprintf_fl(NULL, 0, NULL, format, ap);
 179         va_end(ap);
 180 }
 181
 182 void trace_printf_key(struct trace_key *key, const char *format, ...)
 183 {
 184         va_list ap;
 185         va_start(ap, format);
 186         trace_vprintf_fl(NULL, 0, key, format, ap);
 187         va_end(ap);
 188 }
 189
 190 void trace_argv_printf(const char **argv, const char *format, ...)
 191 {
 192         va_list ap;
 193         va_start(ap, format);
 194         trace_argv_vprintf_fl(NULL, 0, argv, format, ap);
 195         va_end(ap);
 196 }
 197
 198 void trace_strbuf(const char *key, const struct strbuf *data)
 199 {
 200         trace_strbuf_fl(NULL, 0, key, data);
 201 }
 202
 203 #else
 204
 205 void trace_printf_key_fl(const char *file, int line, struct trace_key *key,
 206                          const char *format, ...)
 207 {
 208         va_list ap;
 209         va_start(ap, format);
 210         trace_vprintf_fl(file, line, key, format, ap);
 211         va_end(ap);
 212 }
 213
 214 void trace_argv_printf_fl(const char *file, int line, const char **argv,
 215                           const char *format, ...)
 216 {
 217         va_list ap;
 218         va_start(ap, format);
 219         trace_argv_vprintf_fl(file, line, argv, format, ap);
 220         va_end(ap);
 221 }
 222
 223 #endif /* HAVE_VARIADIC_MACROS */
 224
 225
 226 static const char *quote_crnl(const char *path)
 227 {
 228         static char new_path[PATH_MAX];
 229         const char *p2 = path;
 230         char *p1 = new_path;
 231
 232         if (!path)
 233                 return NULL;
 234
 235         while (*p2) {
 236                 switch (*p2) {
 237                 case '\\': *p1++ = '\\'; *p1++ = '\\'; break;
 238                 case '\n': *p1++ = '\\'; *p1++ = 'n'; break;
 239                 case '\r': *p1++ = '\\'; *p1++ = 'r'; break;
 240                 default:
 241                         *p1++ = *p2;
 242                 }
 243                 p2++;
 244         }
 245         *p1 = '\0';
 246         return new_path;
 247 }
 248
 249 /* FIXME: move prefix to startup_info struct and get rid of this arg */
 250 void trace_repo_setup(const char *prefix)
 251 {
 252         static struct trace_key key = TRACE_KEY_INIT(SETUP);
 253         const char *git_work_tree;
 254         char cwd[PATH_MAX];
 255
 256         if (!trace_want(&key))
 257                 return;
 258
 259         if (!getcwd(cwd, PATH_MAX))
 260                 die("Unable to get current working directory");
 261
 262         if (!(git_work_tree = get_git_work_tree()))
 263                 git_work_tree = "(null)";
 264
 265         if (!prefix)
 266                 prefix = "(null)";
 267
 268         trace_printf_key(&key, "setup: git_dir: %s\n", quote_crnl(get_git_dir()));
 269         trace_printf_key(&key, "setup: worktree: %s\n", quote_crnl(git_work_tree));
 270         trace_printf_key(&key, "setup: cwd: %s\n", quote_crnl(cwd));
 271         trace_printf_key(&key, "setup: prefix: %s\n", quote_crnl(prefix));
 272 }
 273
 274 int trace_want(struct trace_key *key)
 275 {
 276         return !!get_trace_fd(key);
 277 }
 278
 279 #ifdef HAVE_CLOCK_GETTIME
 280
 281 static inline uint64_t highres_nanos(void)
 282 {
 283         struct timespec ts;
 284         if (clock_gettime(CLOCK_MONOTONIC, &ts))
 285                 return 0;
 286         return (uint64_t) ts.tv_sec * 1000000000 + ts.tv_nsec;
 287 }
 288
 289 #elif defined (GIT_WINDOWS_NATIVE)
 290
 291 static inline uint64_t highres_nanos(void)
 292 {
 293         static uint64_t high_ns, scaled_low_ns;
 294         static int scale;
 295         LARGE_INTEGER cnt;
 296
 297         if (!scale) {
 298                 if (!QueryPerformanceFrequency(&cnt))
 299                         return 0;
 300
 301                 /* high_ns = number of ns per cnt.HighPart */
 302                 high_ns = (1000000000LL << 32) / (uint64_t) cnt.QuadPart;
 303
 304                 /*
 305                  * Number of ns per cnt.LowPart is 10^9 / frequency (or
 306                  * high_ns >> 32). For maximum precision, we scale this factor
 307                  * so that it just fits within 32 bit (i.e. won't overflow if
 308                  * multiplied with cnt.LowPart).
 309                  */
 310                 scaled_low_ns = high_ns;
 311                 scale = 32;
 312                 while (scaled_low_ns >= 0x100000000LL) {
 313                         scaled_low_ns >>= 1;
 314                         scale--;
 315                 }
 316         }
 317
 318         /* if QPF worked on initialization, we expect QPC to work as well */
 319         QueryPerformanceCounter(&cnt);
 320
 321         return (high_ns * cnt.HighPart) +
 322                ((scaled_low_ns * cnt.LowPart) >> scale);
 323 }
 324
 325 #else
 326 # define highres_nanos() 0
 327 #endif
 328
 329 static inline uint64_t gettimeofday_nanos(void)
 330 {
 331         struct timeval tv;
 332         gettimeofday(&tv, NULL);
 333         return (uint64_t) tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
 334 }
 335
 336 /*
 337  * Returns nanoseconds since the epoch (01/01/1970), for performance tracing
 338  * (i.e. favoring high precision over wall clock time accuracy).
 339  */
 340 inline uint64_t getnanotime(void)
 341 {
 342         static uint64_t offset;
 343         if (offset > 1) {
 344                 /* initialization succeeded, return offset + high res time */
 345                 return offset + highres_nanos();
 346         } else if (offset == 1) {
 347                 /* initialization failed, fall back to gettimeofday */
 348                 return gettimeofday_nanos();
 349         } else {
 350                 /* initialize offset if high resolution timer works */
 351                 uint64_t now = gettimeofday_nanos();
 352                 uint64_t highres = highres_nanos();
 353                 if (highres)
 354                         offset = now - highres;
 355                 else
 356                         offset = 1;
 357                 return now;
 358         }
 359 }