pkt-line: do not issue flush packets in write_packetized_*()
[git] / pkt-line.c
1 #include "cache.h"
2 #include "pkt-line.h"
3 #include "run-command.h"
4
5 char packet_buffer[LARGE_PACKET_MAX];
6 static const char *packet_trace_prefix = "git";
7 static struct trace_key trace_packet = TRACE_KEY_INIT(PACKET);
8 static struct trace_key trace_pack = TRACE_KEY_INIT(PACKFILE);
9
10 void packet_trace_identity(const char *prog)
11 {
12         packet_trace_prefix = xstrdup(prog);
13 }
14
15 static const char *get_trace_prefix(void)
16 {
17         return in_async() ? "sideband" : packet_trace_prefix;
18 }
19
20 static int packet_trace_pack(const char *buf, unsigned int len, int sideband)
21 {
22         if (!sideband) {
23                 trace_verbatim(&trace_pack, buf, len);
24                 return 1;
25         } else if (len && *buf == '\1') {
26                 trace_verbatim(&trace_pack, buf + 1, len - 1);
27                 return 1;
28         } else {
29                 /* it's another non-pack sideband */
30                 return 0;
31         }
32 }
33
34 static void packet_trace(const char *buf, unsigned int len, int write)
35 {
36         int i;
37         struct strbuf out;
38         static int in_pack, sideband;
39
40         if (!trace_want(&trace_packet) && !trace_want(&trace_pack))
41                 return;
42
43         if (in_pack) {
44                 if (packet_trace_pack(buf, len, sideband))
45                         return;
46         } else if (starts_with(buf, "PACK") || starts_with(buf, "\1PACK")) {
47                 in_pack = 1;
48                 sideband = *buf == '\1';
49                 packet_trace_pack(buf, len, sideband);
50
51                 /*
52                  * Make a note in the human-readable trace that the pack data
53                  * started.
54                  */
55                 buf = "PACK ...";
56                 len = strlen(buf);
57         }
58
59         if (!trace_want(&trace_packet))
60                 return;
61
62         /* +32 is just a guess for header + quoting */
63         strbuf_init(&out, len+32);
64
65         strbuf_addf(&out, "packet: %12s%c ",
66                     get_trace_prefix(), write ? '>' : '<');
67
68         /* XXX we should really handle printable utf8 */
69         for (i = 0; i < len; i++) {
70                 /* suppress newlines */
71                 if (buf[i] == '\n')
72                         continue;
73                 if (buf[i] >= 0x20 && buf[i] <= 0x7e)
74                         strbuf_addch(&out, buf[i]);
75                 else
76                         strbuf_addf(&out, "\\%o", buf[i]);
77         }
78
79         strbuf_addch(&out, '\n');
80         trace_strbuf(&trace_packet, &out);
81         strbuf_release(&out);
82 }
83
84 /*
85  * If we buffered things up above (we don't, but we should),
86  * we'd flush it here
87  */
88 void packet_flush(int fd)
89 {
90         packet_trace("0000", 4, 1);
91         if (write_in_full(fd, "0000", 4) < 0)
92                 die_errno(_("unable to write flush packet"));
93 }
94
95 void packet_delim(int fd)
96 {
97         packet_trace("0001", 4, 1);
98         if (write_in_full(fd, "0001", 4) < 0)
99                 die_errno(_("unable to write delim packet"));
100 }
101
102 void packet_response_end(int fd)
103 {
104         packet_trace("0002", 4, 1);
105         if (write_in_full(fd, "0002", 4) < 0)
106                 die_errno(_("unable to write stateless separator packet"));
107 }
108
109 int packet_flush_gently(int fd)
110 {
111         packet_trace("0000", 4, 1);
112         if (write_in_full(fd, "0000", 4) < 0)
113                 return error(_("flush packet write failed"));
114         return 0;
115 }
116
117 void packet_buf_flush(struct strbuf *buf)
118 {
119         packet_trace("0000", 4, 1);
120         strbuf_add(buf, "0000", 4);
121 }
122
123 void packet_buf_delim(struct strbuf *buf)
124 {
125         packet_trace("0001", 4, 1);
126         strbuf_add(buf, "0001", 4);
127 }
128
129 void set_packet_header(char *buf, int size)
130 {
131         static char hexchar[] = "0123456789abcdef";
132
133         #define hex(a) (hexchar[(a) & 15])
134         buf[0] = hex(size >> 12);
135         buf[1] = hex(size >> 8);
136         buf[2] = hex(size >> 4);
137         buf[3] = hex(size);
138         #undef hex
139 }
140
141 static void format_packet(struct strbuf *out, const char *prefix,
142                           const char *fmt, va_list args)
143 {
144         size_t orig_len, n;
145
146         orig_len = out->len;
147         strbuf_addstr(out, "0000");
148         strbuf_addstr(out, prefix);
149         strbuf_vaddf(out, fmt, args);
150         n = out->len - orig_len;
151
152         if (n > LARGE_PACKET_MAX)
153                 die(_("protocol error: impossibly long line"));
154
155         set_packet_header(&out->buf[orig_len], n);
156         packet_trace(out->buf + orig_len + 4, n - 4, 1);
157 }
158
159 static int packet_write_fmt_1(int fd, int gently, const char *prefix,
160                               const char *fmt, va_list args)
161 {
162         static struct strbuf buf = STRBUF_INIT;
163
164         strbuf_reset(&buf);
165         format_packet(&buf, prefix, fmt, args);
166         if (write_in_full(fd, buf.buf, buf.len) < 0) {
167                 if (!gently) {
168                         check_pipe(errno);
169                         die_errno(_("packet write with format failed"));
170                 }
171                 return error(_("packet write with format failed"));
172         }
173
174         return 0;
175 }
176
177 void packet_write_fmt(int fd, const char *fmt, ...)
178 {
179         va_list args;
180
181         va_start(args, fmt);
182         packet_write_fmt_1(fd, 0, "", fmt, args);
183         va_end(args);
184 }
185
186 int packet_write_fmt_gently(int fd, const char *fmt, ...)
187 {
188         int status;
189         va_list args;
190
191         va_start(args, fmt);
192         status = packet_write_fmt_1(fd, 1, "", fmt, args);
193         va_end(args);
194         return status;
195 }
196
197 static int packet_write_gently(const int fd_out, const char *buf, size_t size)
198 {
199         char header[4];
200         size_t packet_size;
201
202         if (size > LARGE_PACKET_DATA_MAX)
203                 return error(_("packet write failed - data exceeds max packet size"));
204
205         packet_trace(buf, size, 1);
206         packet_size = size + 4;
207
208         set_packet_header(header, packet_size);
209
210         /*
211          * Write the header and the buffer in 2 parts so that we do
212          * not need to allocate a buffer or rely on a static buffer.
213          * This also avoids putting a large buffer on the stack which
214          * might have multi-threading issues.
215          */
216
217         if (write_in_full(fd_out, header, 4) < 0 ||
218             write_in_full(fd_out, buf, size) < 0)
219                 return error(_("packet write failed"));
220         return 0;
221 }
222
223 void packet_write(int fd_out, const char *buf, size_t size)
224 {
225         if (packet_write_gently(fd_out, buf, size))
226                 die_errno(_("packet write failed"));
227 }
228
229 void packet_buf_write(struct strbuf *buf, const char *fmt, ...)
230 {
231         va_list args;
232
233         va_start(args, fmt);
234         format_packet(buf, "", fmt, args);
235         va_end(args);
236 }
237
238 void packet_buf_write_len(struct strbuf *buf, const char *data, size_t len)
239 {
240         size_t orig_len, n;
241
242         orig_len = buf->len;
243         strbuf_addstr(buf, "0000");
244         strbuf_add(buf, data, len);
245         n = buf->len - orig_len;
246
247         if (n > LARGE_PACKET_MAX)
248                 die(_("protocol error: impossibly long line"));
249
250         set_packet_header(&buf->buf[orig_len], n);
251         packet_trace(data, len, 1);
252 }
253
254 int write_packetized_from_fd_no_flush(int fd_in, int fd_out)
255 {
256         char *buf = xmalloc(LARGE_PACKET_DATA_MAX);
257         int err = 0;
258         ssize_t bytes_to_write;
259
260         while (!err) {
261                 bytes_to_write = xread(fd_in, buf, LARGE_PACKET_DATA_MAX);
262                 if (bytes_to_write < 0) {
263                         free(buf);
264                         return COPY_READ_ERROR;
265                 }
266                 if (bytes_to_write == 0)
267                         break;
268                 err = packet_write_gently(fd_out, buf, bytes_to_write);
269         }
270         free(buf);
271         return err;
272 }
273
274 int write_packetized_from_buf_no_flush(const char *src_in, size_t len, int fd_out)
275 {
276         int err = 0;
277         size_t bytes_written = 0;
278         size_t bytes_to_write;
279
280         while (!err) {
281                 if ((len - bytes_written) > LARGE_PACKET_DATA_MAX)
282                         bytes_to_write = LARGE_PACKET_DATA_MAX;
283                 else
284                         bytes_to_write = len - bytes_written;
285                 if (bytes_to_write == 0)
286                         break;
287                 err = packet_write_gently(fd_out, src_in + bytes_written, bytes_to_write);
288                 bytes_written += bytes_to_write;
289         }
290         return err;
291 }
292
293 static int get_packet_data(int fd, char **src_buf, size_t *src_size,
294                            void *dst, unsigned size, int options)
295 {
296         ssize_t ret;
297
298         if (fd >= 0 && src_buf && *src_buf)
299                 BUG("multiple sources given to packet_read");
300
301         /* Read up to "size" bytes from our source, whatever it is. */
302         if (src_buf && *src_buf) {
303                 ret = size < *src_size ? size : *src_size;
304                 memcpy(dst, *src_buf, ret);
305                 *src_buf += ret;
306                 *src_size -= ret;
307         } else {
308                 ret = read_in_full(fd, dst, size);
309                 if (ret < 0)
310                         die_errno(_("read error"));
311         }
312
313         /* And complain if we didn't get enough bytes to satisfy the read. */
314         if (ret != size) {
315                 if (options & PACKET_READ_GENTLE_ON_EOF)
316                         return -1;
317
318                 die(_("the remote end hung up unexpectedly"));
319         }
320
321         return ret;
322 }
323
324 int packet_length(const char lenbuf_hex[4])
325 {
326         int val = hex2chr(lenbuf_hex);
327         return (val < 0) ? val : (val << 8) | hex2chr(lenbuf_hex + 2);
328 }
329
330 enum packet_read_status packet_read_with_status(int fd, char **src_buffer,
331                                                 size_t *src_len, char *buffer,
332                                                 unsigned size, int *pktlen,
333                                                 int options)
334 {
335         int len;
336         char linelen[4];
337
338         if (get_packet_data(fd, src_buffer, src_len, linelen, 4, options) < 0) {
339                 *pktlen = -1;
340                 return PACKET_READ_EOF;
341         }
342
343         len = packet_length(linelen);
344
345         if (len < 0) {
346                 die(_("protocol error: bad line length character: %.4s"), linelen);
347         } else if (!len) {
348                 packet_trace("0000", 4, 0);
349                 *pktlen = 0;
350                 return PACKET_READ_FLUSH;
351         } else if (len == 1) {
352                 packet_trace("0001", 4, 0);
353                 *pktlen = 0;
354                 return PACKET_READ_DELIM;
355         } else if (len == 2) {
356                 packet_trace("0002", 4, 0);
357                 *pktlen = 0;
358                 return PACKET_READ_RESPONSE_END;
359         } else if (len < 4) {
360                 die(_("protocol error: bad line length %d"), len);
361         }
362
363         len -= 4;
364         if ((unsigned)len >= size)
365                 die(_("protocol error: bad line length %d"), len);
366
367         if (get_packet_data(fd, src_buffer, src_len, buffer, len, options) < 0) {
368                 *pktlen = -1;
369                 return PACKET_READ_EOF;
370         }
371
372         if ((options & PACKET_READ_CHOMP_NEWLINE) &&
373             len && buffer[len-1] == '\n')
374                 len--;
375
376         buffer[len] = 0;
377         packet_trace(buffer, len, 0);
378
379         if ((options & PACKET_READ_DIE_ON_ERR_PACKET) &&
380             starts_with(buffer, "ERR "))
381                 die(_("remote error: %s"), buffer + 4);
382
383         *pktlen = len;
384         return PACKET_READ_NORMAL;
385 }
386
387 int packet_read(int fd, char **src_buffer, size_t *src_len,
388                 char *buffer, unsigned size, int options)
389 {
390         int pktlen = -1;
391
392         packet_read_with_status(fd, src_buffer, src_len, buffer, size,
393                                 &pktlen, options);
394
395         return pktlen;
396 }
397
398 static char *packet_read_line_generic(int fd,
399                                       char **src, size_t *src_len,
400                                       int *dst_len)
401 {
402         int len = packet_read(fd, src, src_len,
403                               packet_buffer, sizeof(packet_buffer),
404                               PACKET_READ_CHOMP_NEWLINE);
405         if (dst_len)
406                 *dst_len = len;
407         return (len > 0) ? packet_buffer : NULL;
408 }
409
410 char *packet_read_line(int fd, int *len_p)
411 {
412         return packet_read_line_generic(fd, NULL, NULL, len_p);
413 }
414
415 int packet_read_line_gently(int fd, int *dst_len, char **dst_line)
416 {
417         int len = packet_read(fd, NULL, NULL,
418                               packet_buffer, sizeof(packet_buffer),
419                               PACKET_READ_CHOMP_NEWLINE|PACKET_READ_GENTLE_ON_EOF);
420         if (dst_len)
421                 *dst_len = len;
422         if (dst_line)
423                 *dst_line = (len > 0) ? packet_buffer : NULL;
424         return len;
425 }
426
427 char *packet_read_line_buf(char **src, size_t *src_len, int *dst_len)
428 {
429         return packet_read_line_generic(-1, src, src_len, dst_len);
430 }
431
432 ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out)
433 {
434         int packet_len;
435
436         size_t orig_len = sb_out->len;
437         size_t orig_alloc = sb_out->alloc;
438
439         for (;;) {
440                 strbuf_grow(sb_out, LARGE_PACKET_DATA_MAX);
441                 packet_len = packet_read(fd_in, NULL, NULL,
442                         /* strbuf_grow() above always allocates one extra byte to
443                          * store a '\0' at the end of the string. packet_read()
444                          * writes a '\0' extra byte at the end, too. Let it know
445                          * that there is already room for the extra byte.
446                          */
447                         sb_out->buf + sb_out->len, LARGE_PACKET_DATA_MAX+1,
448                         PACKET_READ_GENTLE_ON_EOF);
449                 if (packet_len <= 0)
450                         break;
451                 sb_out->len += packet_len;
452         }
453
454         if (packet_len < 0) {
455                 if (orig_alloc == 0)
456                         strbuf_release(sb_out);
457                 else
458                         strbuf_setlen(sb_out, orig_len);
459                 return packet_len;
460         }
461         return sb_out->len - orig_len;
462 }
463
464 int recv_sideband(const char *me, int in_stream, int out)
465 {
466         char buf[LARGE_PACKET_MAX + 1];
467         int len;
468         struct strbuf scratch = STRBUF_INIT;
469         enum sideband_type sideband_type;
470
471         while (1) {
472                 int status = packet_read_with_status(in_stream, NULL, NULL,
473                                                      buf, LARGE_PACKET_MAX,
474                                                      &len,
475                                                      PACKET_READ_GENTLE_ON_EOF);
476                 if (!demultiplex_sideband(me, status, buf, len, 0, &scratch,
477                                           &sideband_type))
478                         continue;
479                 switch (sideband_type) {
480                 case SIDEBAND_PRIMARY:
481                         write_or_die(out, buf + 1, len - 1);
482                         break;
483                 default: /* errors: message already written */
484                         if (scratch.len > 0)
485                                 BUG("unhandled incomplete sideband: '%s'",
486                                     scratch.buf);
487                         return sideband_type;
488                 }
489         }
490 }
491
492 /* Packet Reader Functions */
493 void packet_reader_init(struct packet_reader *reader, int fd,
494                         char *src_buffer, size_t src_len,
495                         int options)
496 {
497         memset(reader, 0, sizeof(*reader));
498
499         reader->fd = fd;
500         reader->src_buffer = src_buffer;
501         reader->src_len = src_len;
502         reader->buffer = packet_buffer;
503         reader->buffer_size = sizeof(packet_buffer);
504         reader->options = options;
505         reader->me = "git";
506         reader->hash_algo = &hash_algos[GIT_HASH_SHA1];
507 }
508
509 enum packet_read_status packet_reader_read(struct packet_reader *reader)
510 {
511         struct strbuf scratch = STRBUF_INIT;
512
513         if (reader->line_peeked) {
514                 reader->line_peeked = 0;
515                 return reader->status;
516         }
517
518         /*
519          * Consume all progress packets until a primary payload packet is
520          * received
521          */
522         while (1) {
523                 enum sideband_type sideband_type;
524                 reader->status = packet_read_with_status(reader->fd,
525                                                          &reader->src_buffer,
526                                                          &reader->src_len,
527                                                          reader->buffer,
528                                                          reader->buffer_size,
529                                                          &reader->pktlen,
530                                                          reader->options);
531                 if (!reader->use_sideband)
532                         break;
533                 if (demultiplex_sideband(reader->me, reader->status,
534                                          reader->buffer, reader->pktlen, 1,
535                                          &scratch, &sideband_type))
536                         break;
537         }
538
539         if (reader->status == PACKET_READ_NORMAL)
540                 /* Skip the sideband designator if sideband is used */
541                 reader->line = reader->use_sideband ?
542                         reader->buffer + 1 : reader->buffer;
543         else
544                 reader->line = NULL;
545
546         return reader->status;
547 }
548
549 enum packet_read_status packet_reader_peek(struct packet_reader *reader)
550 {
551         /* Only allow peeking a single line */
552         if (reader->line_peeked)
553                 return reader->status;
554
555         /* Peek a line by reading it and setting peeked flag */
556         packet_reader_read(reader);
557         reader->line_peeked = 1;
558         return reader->status;
559 }
560
561 void packet_writer_init(struct packet_writer *writer, int dest_fd)
562 {
563         writer->dest_fd = dest_fd;
564         writer->use_sideband = 0;
565 }
566
567 void packet_writer_write(struct packet_writer *writer, const char *fmt, ...)
568 {
569         va_list args;
570
571         va_start(args, fmt);
572         packet_write_fmt_1(writer->dest_fd, 0,
573                            writer->use_sideband ? "\001" : "", fmt, args);
574         va_end(args);
575 }
576
577 void packet_writer_error(struct packet_writer *writer, const char *fmt, ...)
578 {
579         va_list args;
580
581         va_start(args, fmt);
582         packet_write_fmt_1(writer->dest_fd, 0,
583                            writer->use_sideband ? "\003" : "ERR ", fmt, args);
584         va_end(args);
585 }
586
587 void packet_writer_delim(struct packet_writer *writer)
588 {
589         packet_delim(writer->dest_fd);
590 }
591
592 void packet_writer_flush(struct packet_writer *writer)
593 {
594         packet_flush(writer->dest_fd);
595 }