aboutsummaryrefslogtreecommitdiff
path: root/trace.c
blob: e583dc63bb8d7062f8b735e701978574e9fcbf25 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
/*
 * GIT - The information manager from hell
 *
 * Copyright (C) 2000-2002 Michael R. Elkins <me@mutt.org>
 * Copyright (C) 2002-2004 Oswald Buddenhagen <ossi@users.sf.net>
 * Copyright (C) 2004 Theodore Y. Ts'o <tytso@mit.edu>
 * Copyright (C) 2006 Mike McCormack
 * Copyright (C) 2006 Christian Couder
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "cache.h"
#include "quote.h"

/* Get a trace file descriptor from "key" env variable. */
static int get_trace_fd(struct trace_key *key)
{
	static struct trace_key trace_default = { "GIT_TRACE" };
	const char *trace;

	/* use default "GIT_TRACE" if NULL */
	if (!key)
		key = &trace_default;

	/* don't open twice */
	if (key->initialized)
		return key->fd;

	trace = getenv(key->key);

	if (!trace || !strcmp(trace, "") ||
	    !strcmp(trace, "0") || !strcasecmp(trace, "false"))
		key->fd = 0;
	else if (!strcmp(trace, "1") || !strcasecmp(trace, "true"))
		key->fd = STDERR_FILENO;
	else if (strlen(trace) == 1 && isdigit(*trace))
		key->fd = atoi(trace);
	else if (is_absolute_path(trace)) {
		int fd = open(trace, O_WRONLY | O_APPEND | O_CREAT, 0666);
		if (fd == -1) {
			fprintf(stderr,
				"Could not open '%s' for tracing: %s\n"
				"Defaulting to tracing on stderr...\n",
				trace, strerror(errno));
			key->fd = STDERR_FILENO;
		} else {
			key->fd = fd;
			key->need_close = 1;
		}
	} else {
		fprintf(stderr, "What does '%s' for %s mean?\n"
			"If you want to trace into a file, then please set "
			"%s to an absolute pathname (starting with /).\n"
			"Defaulting to tracing on stderr...\n",
			trace, key->key, key->key);
		key->fd = STDERR_FILENO;
	}

	key->initialized = 1;
	return key->fd;
}

void trace_disable(struct trace_key *key)
{
	if (key->need_close)
		close(key->fd);
	key->fd = 0;
	key->initialized = 1;
	key->need_close = 0;
}

static const char err_msg[] = "Could not trace into fd given by "
	"GIT_TRACE environment variable";

static int prepare_trace_line(const char *file, int line,
			      struct trace_key *key, struct strbuf *buf)
{
	static struct trace_key trace_bare = TRACE_KEY_INIT(BARE);
	struct timeval tv;
	struct tm tm;
	time_t secs;

	if (!trace_want(key))
		return 0;

	set_try_to_free_routine(NULL);	/* is never reset */

	/* unit tests may want to disable additional trace output */
	if (trace_want(&trace_bare))
		return 1;

	/* print current timestamp */
	gettimeofday(&tv, NULL);
	secs = tv.tv_sec;
	localtime_r(&secs, &tm);
	strbuf_addf(buf, "%02d:%02d:%02d.%06ld ", tm.tm_hour, tm.tm_min,
		    tm.tm_sec, (long) tv.tv_usec);

#ifdef HAVE_VARIADIC_MACROS
	/* print file:line */
	strbuf_addf(buf, "%s:%d ", file, line);
	/* align trace output (column 40 catches most files names in git) */
	while (buf->len < 40)
		strbuf_addch(buf, ' ');
#endif

	return 1;
}

static void print_trace_line(struct trace_key *key, struct strbuf *buf)
{
	/* append newline if missing */
	if (buf->len && buf->buf[buf->len - 1] != '\n')
		strbuf_addch(buf, '\n');

	write_or_whine_pipe(get_trace_fd(key), buf->buf, buf->len, err_msg);
	strbuf_release(buf);
}

static void trace_vprintf_fl(const char *file, int line, struct trace_key *key,
			     const char *format, va_list ap)
{
	struct strbuf buf = STRBUF_INIT;

	if (!prepare_trace_line(file, line, key, &buf))
		return;

	strbuf_vaddf(&buf, format, ap);
	print_trace_line(key, &buf);
}

static void trace_argv_vprintf_fl(const char *file, int line,
				  const char **argv, const char *format,
				  va_list ap)
{
	struct strbuf buf = STRBUF_INIT;

	if (!prepare_trace_line(file, line, NULL, &buf))
		return;

	strbuf_vaddf(&buf, format, ap);

	sq_quote_argv(&buf, argv, 0);
	print_trace_line(NULL, &buf);
}

void trace_strbuf_fl(const char *file, int line, struct trace_key *key,
		     const struct strbuf *data)
{
	struct strbuf buf = STRBUF_INIT;

	if (!prepare_trace_line(file, line, key, &buf))
		return;

	strbuf_addbuf(&buf, data);
	print_trace_line(key, &buf);
}

static struct trace_key trace_perf_key = TRACE_KEY_INIT(PERFORMANCE);

static void trace_performance_vprintf_fl(const char *file, int line,
					 uint64_t nanos, const char *format,
					 va_list ap)
{
	struct strbuf buf = STRBUF_INIT;

	if (!prepare_trace_line(file, line, &trace_perf_key, &buf))
		return;

	strbuf_addf(&buf, "performance: %.9f s", (double) nanos / 1000000000);

	if (format && *format) {
		strbuf_addstr(&buf, ": ");
		strbuf_vaddf(&buf, format, ap);
	}

	print_trace_line(&trace_perf_key, &buf);
}

#ifndef HAVE_VARIADIC_MACROS

void trace_printf(const char *format, ...)
{
	va_list ap;
	va_start(ap, format);
	trace_vprintf_fl(NULL, 0, NULL, format, ap);
	va_end(ap);
}

void trace_printf_key(struct trace_key *key, const char *format, ...)
{
	va_list ap;
	va_start(ap, format);
	trace_vprintf_fl(NULL, 0, key, format, ap);
	va_end(ap);
}

void trace_argv_printf(const char **argv, const char *format, ...)
{
	va_list ap;
	va_start(ap, format);
	trace_argv_vprintf_fl(NULL, 0, argv, format, ap);
	va_end(ap);
}

void trace_strbuf(const char *key, const struct strbuf *data)
{
	trace_strbuf_fl(NULL, 0, key, data);
}

void trace_performance(uint64_t nanos, const char *format, ...)
{
	va_list ap;
	va_start(ap, format);
	trace_performance_vprintf_fl(NULL, 0, nanos, format, ap);
	va_end(ap);
}

void trace_performance_since(uint64_t start, const char *format, ...)
{
	va_list ap;
	va_start(ap, format);
	trace_performance_vprintf_fl(NULL, 0, getnanotime() - start,
				     format, ap);
	va_end(ap);
}

#else

void trace_printf_key_fl(const char *file, int line, struct trace_key *key,
			 const char *format, ...)
{
	va_list ap;
	va_start(ap, format);
	trace_vprintf_fl(file, line, key, format, ap);
	va_end(ap);
}

void trace_argv_printf_fl(const char *file, int line, const char **argv,
			  const char *format, ...)
{
	va_list ap;
	va_start(ap, format);
	trace_argv_vprintf_fl(file, line, argv, format, ap);
	va_end(ap);
}

void trace_performance_fl(const char *file, int line, uint64_t nanos,
			      const char *format, ...)
{
	va_list ap;
	va_start(ap, format);
	trace_performance_vprintf_fl(file, line, nanos, format, ap);
	va_end(ap);
}

#endif /* HAVE_VARIADIC_MACROS */


static const char *quote_crnl(const char *path)
{
	static char new_path[PATH_MAX];
	const char *p2 = path;
	char *p1 = new_path;

	if (!path)
		return NULL;

	while (*p2) {
		switch (*p2) {
		case '\\': *p1++ = '\\'; *p1++ = '\\'; break;
		case '\n': *p1++ = '\\'; *p1++ = 'n'; break;
		case '\r': *p1++ = '\\'; *p1++ = 'r'; break;
		default:
			*p1++ = *p2;
		}
		p2++;
	}
	*p1 = '\0';
	return new_path;
}

/* FIXME: move prefix to startup_info struct and get rid of this arg */
void trace_repo_setup(const char *prefix)
{
	static struct trace_key key = TRACE_KEY_INIT(SETUP);
	const char *git_work_tree;
	char cwd[PATH_MAX];

	if (!trace_want(&key))
		return;

	if (!getcwd(cwd, PATH_MAX))
		die("Unable to get current working directory");

	if (!(git_work_tree = get_git_work_tree()))
		git_work_tree = "(null)";

	if (!prefix)
		prefix = "(null)";

	trace_printf_key(&key, "setup: git_dir: %s\n", quote_crnl(get_git_dir()));
	trace_printf_key(&key, "setup: worktree: %s\n", quote_crnl(git_work_tree));
	trace_printf_key(&key, "setup: cwd: %s\n", quote_crnl(cwd));
	trace_printf_key(&key, "setup: prefix: %s\n", quote_crnl(prefix));
}

int trace_want(struct trace_key *key)
{
	return !!get_trace_fd(key);
}

#ifdef HAVE_CLOCK_GETTIME

static inline uint64_t highres_nanos(void)
{
	struct timespec ts;
	if (clock_gettime(CLOCK_MONOTONIC, &ts))
		return 0;
	return (uint64_t) ts.tv_sec * 1000000000 + ts.tv_nsec;
}

#elif defined (GIT_WINDOWS_NATIVE)

static inline uint64_t highres_nanos(void)
{
	static uint64_t high_ns, scaled_low_ns;
	static int scale;
	LARGE_INTEGER cnt;

	if (!scale) {
		if (!QueryPerformanceFrequency(&cnt))
			return 0;

		/* high_ns = number of ns per cnt.HighPart */
		high_ns = (1000000000LL << 32) / (uint64_t) cnt.QuadPart;

		/*
		 * Number of ns per cnt.LowPart is 10^9 / frequency (or
		 * high_ns >> 32). For maximum precision, we scale this factor
		 * so that it just fits within 32 bit (i.e. won't overflow if
		 * multiplied with cnt.LowPart).
		 */
		scaled_low_ns = high_ns;
		scale = 32;
		while (scaled_low_ns >= 0x100000000LL) {
			scaled_low_ns >>= 1;
			scale--;
		}
	}

	/* if QPF worked on initialization, we expect QPC to work as well */
	QueryPerformanceCounter(&cnt);

	return (high_ns * cnt.HighPart) +
	       ((scaled_low_ns * cnt.LowPart) >> scale);
}

#else
# define highres_nanos() 0
#endif

static inline uint64_t gettimeofday_nanos(void)
{
	struct timeval tv;
	gettimeofday(&tv, NULL);
	return (uint64_t) tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
}

/*
 * Returns nanoseconds since the epoch (01/01/1970), for performance tracing
 * (i.e. favoring high precision over wall clock time accuracy).
 */
inline uint64_t getnanotime(void)
{
	static uint64_t offset;
	if (offset > 1) {
		/* initialization succeeded, return offset + high res time */
		return offset + highres_nanos();
	} else if (offset == 1) {
		/* initialization failed, fall back to gettimeofday */
		return gettimeofday_nanos();
	} else {
		/* initialize offset if high resolution timer works */
		uint64_t now = gettimeofday_nanos();
		uint64_t highres = highres_nanos();
		if (highres)
			offset = now - highres;
		else
			offset = 1;
		return now;
	}
}

static uint64_t command_start_time;
static struct strbuf command_line = STRBUF_INIT;

static void print_command_performance_atexit(void)
{
	trace_performance_since(command_start_time, "git command:%s",
				command_line.buf);
}

void trace_command_performance(const char **argv)
{
	if (!trace_want(&trace_perf_key))
		return;

	if (!command_start_time)
		atexit(print_command_performance_atexit);

	strbuf_reset(&command_line);
	sq_quote_argv(&command_line, argv, 0);
	command_start_time = getnanotime();
}