about summary refs log tree commit diff
path: root/third_party/git/pkt-line.c
blob: 844c253ccd9a9ee770fe494a0cce84f53dc8fed8 (plain) (blame)
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
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
#include "cache.h"
#include "pkt-line.h"
#include "run-command.h"

char packet_buffer[LARGE_PACKET_MAX];
static const char *packet_trace_prefix = "git";
static struct trace_key trace_packet = TRACE_KEY_INIT(PACKET);
static struct trace_key trace_pack = TRACE_KEY_INIT(PACKFILE);

void packet_trace_identity(const char *prog)
{
	packet_trace_prefix = xstrdup(prog);
}

static const char *get_trace_prefix(void)
{
	return in_async() ? "sideband" : packet_trace_prefix;
}

static int packet_trace_pack(const char *buf, unsigned int len, int sideband)
{
	if (!sideband) {
		trace_verbatim(&trace_pack, buf, len);
		return 1;
	} else if (len && *buf == '\1') {
		trace_verbatim(&trace_pack, buf + 1, len - 1);
		return 1;
	} else {
		/* it's another non-pack sideband */
		return 0;
	}
}

static void packet_trace(const char *buf, unsigned int len, int write)
{
	int i;
	struct strbuf out;
	static int in_pack, sideband;

	if (!trace_want(&trace_packet) && !trace_want(&trace_pack))
		return;

	if (in_pack) {
		if (packet_trace_pack(buf, len, sideband))
			return;
	} else if (starts_with(buf, "PACK") || starts_with(buf, "\1PACK")) {
		in_pack = 1;
		sideband = *buf == '\1';
		packet_trace_pack(buf, len, sideband);

		/*
		 * Make a note in the human-readable trace that the pack data
		 * started.
		 */
		buf = "PACK ...";
		len = strlen(buf);
	}

	if (!trace_want(&trace_packet))
		return;

	/* +32 is just a guess for header + quoting */
	strbuf_init(&out, len+32);

	strbuf_addf(&out, "packet: %12s%c ",
		    get_trace_prefix(), write ? '>' : '<');

	/* XXX we should really handle printable utf8 */
	for (i = 0; i < len; i++) {
		/* suppress newlines */
		if (buf[i] == '\n')
			continue;
		if (buf[i] >= 0x20 && buf[i] <= 0x7e)
			strbuf_addch(&out, buf[i]);
		else
			strbuf_addf(&out, "\\%o", buf[i]);
	}

	strbuf_addch(&out, '\n');
	trace_strbuf(&trace_packet, &out);
	strbuf_release(&out);
}

/*
 * If we buffered things up above (we don't, but we should),
 * we'd flush it here
 */
void packet_flush(int fd)
{
	packet_trace("0000", 4, 1);
	if (write_in_full(fd, "0000", 4) < 0)
		die_errno(_("unable to write flush packet"));
}

void packet_delim(int fd)
{
	packet_trace("0001", 4, 1);
	if (write_in_full(fd, "0001", 4) < 0)
		die_errno(_("unable to write delim packet"));
}

void packet_response_end(int fd)
{
	packet_trace("0002", 4, 1);
	if (write_in_full(fd, "0002", 4) < 0)
		die_errno(_("unable to write stateless separator packet"));
}

int packet_flush_gently(int fd)
{
	packet_trace("0000", 4, 1);
	if (write_in_full(fd, "0000", 4) < 0)
		return error(_("flush packet write failed"));
	return 0;
}

void packet_buf_flush(struct strbuf *buf)
{
	packet_trace("0000", 4, 1);
	strbuf_add(buf, "0000", 4);
}

void packet_buf_delim(struct strbuf *buf)
{
	packet_trace("0001", 4, 1);
	strbuf_add(buf, "0001", 4);
}

void set_packet_header(char *buf, int size)
{
	static char hexchar[] = "0123456789abcdef";

	#define hex(a) (hexchar[(a) & 15])
	buf[0] = hex(size >> 12);
	buf[1] = hex(size >> 8);
	buf[2] = hex(size >> 4);
	buf[3] = hex(size);
	#undef hex
}

static void format_packet(struct strbuf *out, const char *prefix,
			  const char *fmt, va_list args)
{
	size_t orig_len, n;

	orig_len = out->len;
	strbuf_addstr(out, "0000");
	strbuf_addstr(out, prefix);
	strbuf_vaddf(out, fmt, args);
	n = out->len - orig_len;

	if (n > LARGE_PACKET_MAX)
		die(_("protocol error: impossibly long line"));

	set_packet_header(&out->buf[orig_len], n);
	packet_trace(out->buf + orig_len + 4, n - 4, 1);
}

static int packet_write_fmt_1(int fd, int gently, const char *prefix,
			      const char *fmt, va_list args)
{
	static struct strbuf buf = STRBUF_INIT;

	strbuf_reset(&buf);
	format_packet(&buf, prefix, fmt, args);
	if (write_in_full(fd, buf.buf, buf.len) < 0) {
		if (!gently) {
			check_pipe(errno);
			die_errno(_("packet write with format failed"));
		}
		return error(_("packet write with format failed"));
	}

	return 0;
}

void packet_write_fmt(int fd, const char *fmt, ...)
{
	va_list args;

	va_start(args, fmt);
	packet_write_fmt_1(fd, 0, "", fmt, args);
	va_end(args);
}

int packet_write_fmt_gently(int fd, const char *fmt, ...)
{
	int status;
	va_list args;

	va_start(args, fmt);
	status = packet_write_fmt_1(fd, 1, "", fmt, args);
	va_end(args);
	return status;
}

static int packet_write_gently(const int fd_out, const char *buf, size_t size)
{
	static char packet_write_buffer[LARGE_PACKET_MAX];
	size_t packet_size;

	if (size > sizeof(packet_write_buffer) - 4)
		return error(_("packet write failed - data exceeds max packet size"));

	packet_trace(buf, size, 1);
	packet_size = size + 4;
	set_packet_header(packet_write_buffer, packet_size);
	memcpy(packet_write_buffer + 4, buf, size);
	if (write_in_full(fd_out, packet_write_buffer, packet_size) < 0)
		return error(_("packet write failed"));
	return 0;
}

void packet_write(int fd_out, const char *buf, size_t size)
{
	if (packet_write_gently(fd_out, buf, size))
		die_errno(_("packet write failed"));
}

void packet_buf_write(struct strbuf *buf, const char *fmt, ...)
{
	va_list args;

	va_start(args, fmt);
	format_packet(buf, "", fmt, args);
	va_end(args);
}

void packet_buf_write_len(struct strbuf *buf, const char *data, size_t len)
{
	size_t orig_len, n;

	orig_len = buf->len;
	strbuf_addstr(buf, "0000");
	strbuf_add(buf, data, len);
	n = buf->len - orig_len;

	if (n > LARGE_PACKET_MAX)
		die(_("protocol error: impossibly long line"));

	set_packet_header(&buf->buf[orig_len], n);
	packet_trace(data, len, 1);
}

int write_packetized_from_fd(int fd_in, int fd_out)
{
	static char buf[LARGE_PACKET_DATA_MAX];
	int err = 0;
	ssize_t bytes_to_write;

	while (!err) {
		bytes_to_write = xread(fd_in, buf, sizeof(buf));
		if (bytes_to_write < 0)
			return COPY_READ_ERROR;
		if (bytes_to_write == 0)
			break;
		err = packet_write_gently(fd_out, buf, bytes_to_write);
	}
	if (!err)
		err = packet_flush_gently(fd_out);
	return err;
}

int write_packetized_from_buf(const char *src_in, size_t len, int fd_out)
{
	int err = 0;
	size_t bytes_written = 0;
	size_t bytes_to_write;

	while (!err) {
		if ((len - bytes_written) > LARGE_PACKET_DATA_MAX)
			bytes_to_write = LARGE_PACKET_DATA_MAX;
		else
			bytes_to_write = len - bytes_written;
		if (bytes_to_write == 0)
			break;
		err = packet_write_gently(fd_out, src_in + bytes_written, bytes_to_write);
		bytes_written += bytes_to_write;
	}
	if (!err)
		err = packet_flush_gently(fd_out);
	return err;
}

static int get_packet_data(int fd, char **src_buf, size_t *src_size,
			   void *dst, unsigned size, int options)
{
	ssize_t ret;

	if (fd >= 0 && src_buf && *src_buf)
		BUG("multiple sources given to packet_read");

	/* Read up to "size" bytes from our source, whatever it is. */
	if (src_buf && *src_buf) {
		ret = size < *src_size ? size : *src_size;
		memcpy(dst, *src_buf, ret);
		*src_buf += ret;
		*src_size -= ret;
	} else {
		ret = read_in_full(fd, dst, size);
		if (ret < 0)
			die_errno(_("read error"));
	}

	/* And complain if we didn't get enough bytes to satisfy the read. */
	if (ret != size) {
		if (options & PACKET_READ_GENTLE_ON_EOF)
			return -1;

		die(_("the remote end hung up unexpectedly"));
	}

	return ret;
}

int packet_length(const char lenbuf_hex[4])
{
	int val = hex2chr(lenbuf_hex);
	return (val < 0) ? val : (val << 8) | hex2chr(lenbuf_hex + 2);
}

enum packet_read_status packet_read_with_status(int fd, char **src_buffer,
						size_t *src_len, char *buffer,
						unsigned size, int *pktlen,
						int options)
{
	int len;
	char linelen[4];

	if (get_packet_data(fd, src_buffer, src_len, linelen, 4, options) < 0) {
		*pktlen = -1;
		return PACKET_READ_EOF;
	}

	len = packet_length(linelen);

	if (len < 0) {
		die(_("protocol error: bad line length character: %.4s"), linelen);
	} else if (!len) {
		packet_trace("0000", 4, 0);
		*pktlen = 0;
		return PACKET_READ_FLUSH;
	} else if (len == 1) {
		packet_trace("0001", 4, 0);
		*pktlen = 0;
		return PACKET_READ_DELIM;
	} else if (len == 2) {
		packet_trace("0002", 4, 0);
		*pktlen = 0;
		return PACKET_READ_RESPONSE_END;
	} else if (len < 4) {
		die(_("protocol error: bad line length %d"), len);
	}

	len -= 4;
	if ((unsigned)len >= size)
		die(_("protocol error: bad line length %d"), len);

	if (get_packet_data(fd, src_buffer, src_len, buffer, len, options) < 0) {
		*pktlen = -1;
		return PACKET_READ_EOF;
	}

	if ((options & PACKET_READ_CHOMP_NEWLINE) &&
	    len && buffer[len-1] == '\n')
		len--;

	buffer[len] = 0;
	packet_trace(buffer, len, 0);

	if ((options & PACKET_READ_DIE_ON_ERR_PACKET) &&
	    starts_with(buffer, "ERR "))
		die(_("remote error: %s"), buffer + 4);

	*pktlen = len;
	return PACKET_READ_NORMAL;
}

int packet_read(int fd, char **src_buffer, size_t *src_len,
		char *buffer, unsigned size, int options)
{
	int pktlen = -1;

	packet_read_with_status(fd, src_buffer, src_len, buffer, size,
				&pktlen, options);

	return pktlen;
}

static char *packet_read_line_generic(int fd,
				      char **src, size_t *src_len,
				      int *dst_len)
{
	int len = packet_read(fd, src, src_len,
			      packet_buffer, sizeof(packet_buffer),
			      PACKET_READ_CHOMP_NEWLINE);
	if (dst_len)
		*dst_len = len;
	return (len > 0) ? packet_buffer : NULL;
}

char *packet_read_line(int fd, int *len_p)
{
	return packet_read_line_generic(fd, NULL, NULL, len_p);
}

int packet_read_line_gently(int fd, int *dst_len, char **dst_line)
{
	int len = packet_read(fd, NULL, NULL,
			      packet_buffer, sizeof(packet_buffer),
			      PACKET_READ_CHOMP_NEWLINE|PACKET_READ_GENTLE_ON_EOF);
	if (dst_len)
		*dst_len = len;
	if (dst_line)
		*dst_line = (len > 0) ? packet_buffer : NULL;
	return len;
}

char *packet_read_line_buf(char **src, size_t *src_len, int *dst_len)
{
	return packet_read_line_generic(-1, src, src_len, dst_len);
}

ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out)
{
	int packet_len;

	size_t orig_len = sb_out->len;
	size_t orig_alloc = sb_out->alloc;

	for (;;) {
		strbuf_grow(sb_out, LARGE_PACKET_DATA_MAX);
		packet_len = packet_read(fd_in, NULL, NULL,
			/* strbuf_grow() above always allocates one extra byte to
			 * store a '\0' at the end of the string. packet_read()
			 * writes a '\0' extra byte at the end, too. Let it know
			 * that there is already room for the extra byte.
			 */
			sb_out->buf + sb_out->len, LARGE_PACKET_DATA_MAX+1,
			PACKET_READ_GENTLE_ON_EOF);
		if (packet_len <= 0)
			break;
		sb_out->len += packet_len;
	}

	if (packet_len < 0) {
		if (orig_alloc == 0)
			strbuf_release(sb_out);
		else
			strbuf_setlen(sb_out, orig_len);
		return packet_len;
	}
	return sb_out->len - orig_len;
}

int recv_sideband(const char *me, int in_stream, int out)
{
	char buf[LARGE_PACKET_MAX + 1];
	int len;
	struct strbuf scratch = STRBUF_INIT;
	enum sideband_type sideband_type;

	while (1) {
		len = packet_read(in_stream, NULL, NULL, buf, LARGE_PACKET_MAX,
				  0);
		if (!demultiplex_sideband(me, buf, len, 0, &scratch,
					  &sideband_type))
			continue;
		switch (sideband_type) {
		case SIDEBAND_PRIMARY:
			write_or_die(out, buf + 1, len - 1);
			break;
		default: /* errors: message already written */
			return sideband_type;
		}
	}
}

/* Packet Reader Functions */
void packet_reader_init(struct packet_reader *reader, int fd,
			char *src_buffer, size_t src_len,
			int options)
{
	memset(reader, 0, sizeof(*reader));

	reader->fd = fd;
	reader->src_buffer = src_buffer;
	reader->src_len = src_len;
	reader->buffer = packet_buffer;
	reader->buffer_size = sizeof(packet_buffer);
	reader->options = options;
	reader->me = "git";
	reader->hash_algo = &hash_algos[GIT_HASH_SHA1];
}

enum packet_read_status packet_reader_read(struct packet_reader *reader)
{
	struct strbuf scratch = STRBUF_INIT;

	if (reader->line_peeked) {
		reader->line_peeked = 0;
		return reader->status;
	}

	/*
	 * Consume all progress packets until a primary payload packet is
	 * received
	 */
	while (1) {
		enum sideband_type sideband_type;
		reader->status = packet_read_with_status(reader->fd,
							 &reader->src_buffer,
							 &reader->src_len,
							 reader->buffer,
							 reader->buffer_size,
							 &reader->pktlen,
							 reader->options);
		if (!reader->use_sideband)
			break;
		if (demultiplex_sideband(reader->me, reader->buffer,
					 reader->pktlen, 1, &scratch,
					 &sideband_type))
			break;
	}

	if (reader->status == PACKET_READ_NORMAL)
		/* Skip the sideband designator if sideband is used */
		reader->line = reader->use_sideband ?
			reader->buffer + 1 : reader->buffer;
	else
		reader->line = NULL;

	return reader->status;
}

enum packet_read_status packet_reader_peek(struct packet_reader *reader)
{
	/* Only allow peeking a single line */
	if (reader->line_peeked)
		return reader->status;

	/* Peek a line by reading it and setting peeked flag */
	packet_reader_read(reader);
	reader->line_peeked = 1;
	return reader->status;
}

void packet_writer_init(struct packet_writer *writer, int dest_fd)
{
	writer->dest_fd = dest_fd;
	writer->use_sideband = 0;
}

void packet_writer_write(struct packet_writer *writer, const char *fmt, ...)
{
	va_list args;

	va_start(args, fmt);
	packet_write_fmt_1(writer->dest_fd, 0,
			   writer->use_sideband ? "\001" : "", fmt, args);
	va_end(args);
}

void packet_writer_error(struct packet_writer *writer, const char *fmt, ...)
{
	va_list args;

	va_start(args, fmt);
	packet_write_fmt_1(writer->dest_fd, 0,
			   writer->use_sideband ? "\003" : "ERR ", fmt, args);
	va_end(args);
}

void packet_writer_delim(struct packet_writer *writer)
{
	packet_delim(writer->dest_fd);
}

void packet_writer_flush(struct packet_writer *writer)
{
	packet_flush(writer->dest_fd);
}