Emit helpful status for accidental "git stash" save
[git] / upload-pack.c
1 #include "cache.h"
2 #include "refs.h"
3 #include "pkt-line.h"
4 #include "sideband.h"
5 #include "tag.h"
6 #include "object.h"
7 #include "commit.h"
8 #include "exec_cmd.h"
9 #include "diff.h"
10 #include "revision.h"
11 #include "list-objects.h"
12 #include "run-command.h"
13
14 static const char upload_pack_usage[] = "git-upload-pack [--strict] [--timeout=nn] <dir>";
15
16 /* bits #0..7 in revision.h, #8..10 in commit.c */
17 #define THEY_HAVE       (1u << 11)
18 #define OUR_REF         (1u << 12)
19 #define WANTED          (1u << 13)
20 #define COMMON_KNOWN    (1u << 14)
21 #define REACHABLE       (1u << 15)
22
23 #define SHALLOW         (1u << 16)
24 #define NOT_SHALLOW     (1u << 17)
25 #define CLIENT_SHALLOW  (1u << 18)
26
27 static unsigned long oldest_have;
28
29 static int multi_ack, nr_our_refs;
30 static int use_thin_pack, use_ofs_delta, no_progress;
31 static struct object_array have_obj;
32 static struct object_array want_obj;
33 static unsigned int timeout;
34 /* 0 for no sideband,
35  * otherwise maximum packet size (up to 65520 bytes).
36  */
37 static int use_sideband;
38
39 static void reset_timeout(void)
40 {
41         alarm(timeout);
42 }
43
44 static int strip(char *line, int len)
45 {
46         if (len && line[len-1] == '\n')
47                 line[--len] = 0;
48         return len;
49 }
50
51 static ssize_t send_client_data(int fd, const char *data, ssize_t sz)
52 {
53         if (use_sideband)
54                 return send_sideband(1, fd, data, sz, use_sideband);
55         if (fd == 3)
56                 /* emergency quit */
57                 fd = 2;
58         if (fd == 2) {
59                 /* XXX: are we happy to lose stuff here? */
60                 xwrite(fd, data, sz);
61                 return sz;
62         }
63         return safe_write(fd, data, sz);
64 }
65
66 static FILE *pack_pipe = NULL;
67 static void show_commit(struct commit *commit)
68 {
69         if (commit->object.flags & BOUNDARY)
70                 fputc('-', pack_pipe);
71         if (fputs(sha1_to_hex(commit->object.sha1), pack_pipe) < 0)
72                 die("broken output pipe");
73         fputc('\n', pack_pipe);
74         fflush(pack_pipe);
75         free(commit->buffer);
76         commit->buffer = NULL;
77 }
78
79 static void show_object(struct object_array_entry *p)
80 {
81         /* An object with name "foo\n0000000..." can be used to
82          * confuse downstream git-pack-objects very badly.
83          */
84         const char *ep = strchr(p->name, '\n');
85         if (ep) {
86                 fprintf(pack_pipe, "%s %.*s\n", sha1_to_hex(p->item->sha1),
87                        (int) (ep - p->name),
88                        p->name);
89         }
90         else
91                 fprintf(pack_pipe, "%s %s\n",
92                                 sha1_to_hex(p->item->sha1), p->name);
93 }
94
95 static void show_edge(struct commit *commit)
96 {
97         fprintf(pack_pipe, "-%s\n", sha1_to_hex(commit->object.sha1));
98 }
99
100 static int do_rev_list(int fd, void *create_full_pack)
101 {
102         int i;
103         struct rev_info revs;
104
105         pack_pipe = fdopen(fd, "w");
106         if (create_full_pack)
107                 use_thin_pack = 0; /* no point doing it */
108         init_revisions(&revs, NULL);
109         revs.tag_objects = 1;
110         revs.tree_objects = 1;
111         revs.blob_objects = 1;
112         if (use_thin_pack)
113                 revs.edge_hint = 1;
114
115         if (create_full_pack) {
116                 const char *args[] = {"rev-list", "--all", NULL};
117                 setup_revisions(2, args, &revs, NULL);
118         } else {
119                 for (i = 0; i < want_obj.nr; i++) {
120                         struct object *o = want_obj.objects[i].item;
121                         /* why??? */
122                         o->flags &= ~UNINTERESTING;
123                         add_pending_object(&revs, o, NULL);
124                 }
125                 for (i = 0; i < have_obj.nr; i++) {
126                         struct object *o = have_obj.objects[i].item;
127                         o->flags |= UNINTERESTING;
128                         add_pending_object(&revs, o, NULL);
129                 }
130                 setup_revisions(0, NULL, &revs, NULL);
131         }
132         prepare_revision_walk(&revs);
133         mark_edges_uninteresting(revs.commits, &revs, show_edge);
134         traverse_commit_list(&revs, show_commit, show_object);
135         return 0;
136 }
137
138 static void create_pack_file(void)
139 {
140         struct async rev_list;
141         struct child_process pack_objects;
142         int create_full_pack = (nr_our_refs == want_obj.nr && !have_obj.nr);
143         char data[8193], progress[128];
144         char abort_msg[] = "aborting due to possible repository "
145                 "corruption on the remote side.";
146         int buffered = -1;
147         ssize_t sz;
148         const char *argv[10];
149         int arg = 0;
150
151         rev_list.proc = do_rev_list;
152         /* .data is just a boolean: any non-NULL value will do */
153         rev_list.data = create_full_pack ? &rev_list : NULL;
154         if (start_async(&rev_list))
155                 die("git-upload-pack: unable to fork git-rev-list");
156
157         argv[arg++] = "pack-objects";
158         argv[arg++] = "--stdout";
159         if (!no_progress)
160                 argv[arg++] = "--progress";
161         if (use_ofs_delta)
162                 argv[arg++] = "--delta-base-offset";
163         argv[arg++] = NULL;
164
165         memset(&pack_objects, 0, sizeof(pack_objects));
166         pack_objects.in = rev_list.out; /* start_command closes it */
167         pack_objects.out = -1;
168         pack_objects.err = -1;
169         pack_objects.git_cmd = 1;
170         pack_objects.argv = argv;
171
172         if (start_command(&pack_objects))
173                 die("git-upload-pack: unable to fork git-pack-objects");
174
175         /* We read from pack_objects.err to capture stderr output for
176          * progress bar, and pack_objects.out to capture the pack data.
177          */
178
179         while (1) {
180                 struct pollfd pfd[2];
181                 int pe, pu, pollsize;
182
183                 reset_timeout();
184
185                 pollsize = 0;
186                 pe = pu = -1;
187
188                 if (0 <= pack_objects.out) {
189                         pfd[pollsize].fd = pack_objects.out;
190                         pfd[pollsize].events = POLLIN;
191                         pu = pollsize;
192                         pollsize++;
193                 }
194                 if (0 <= pack_objects.err) {
195                         pfd[pollsize].fd = pack_objects.err;
196                         pfd[pollsize].events = POLLIN;
197                         pe = pollsize;
198                         pollsize++;
199                 }
200
201                 if (!pollsize)
202                         break;
203
204                 if (poll(pfd, pollsize, -1) < 0) {
205                         if (errno != EINTR) {
206                                 error("poll failed, resuming: %s",
207                                       strerror(errno));
208                                 sleep(1);
209                         }
210                         continue;
211                 }
212                 if (0 <= pu && (pfd[pu].revents & (POLLIN|POLLHUP))) {
213                         /* Data ready; we keep the last byte to ourselves
214                          * in case we detect broken rev-list, so that we
215                          * can leave the stream corrupted.  This is
216                          * unfortunate -- unpack-objects would happily
217                          * accept a valid packdata with trailing garbage,
218                          * so appending garbage after we pass all the
219                          * pack data is not good enough to signal
220                          * breakage to downstream.
221                          */
222                         char *cp = data;
223                         ssize_t outsz = 0;
224                         if (0 <= buffered) {
225                                 *cp++ = buffered;
226                                 outsz++;
227                         }
228                         sz = xread(pack_objects.out, cp,
229                                   sizeof(data) - outsz);
230                         if (0 < sz)
231                                         ;
232                         else if (sz == 0) {
233                                 close(pack_objects.out);
234                                 pack_objects.out = -1;
235                         }
236                         else
237                                 goto fail;
238                         sz += outsz;
239                         if (1 < sz) {
240                                 buffered = data[sz-1] & 0xFF;
241                                 sz--;
242                         }
243                         else
244                                 buffered = -1;
245                         sz = send_client_data(1, data, sz);
246                         if (sz < 0)
247                                 goto fail;
248                 }
249                 if (0 <= pe && (pfd[pe].revents & (POLLIN|POLLHUP))) {
250                         /* Status ready; we ship that in the side-band
251                          * or dump to the standard error.
252                          */
253                         sz = xread(pack_objects.err, progress,
254                                   sizeof(progress));
255                         if (0 < sz)
256                                 send_client_data(2, progress, sz);
257                         else if (sz == 0) {
258                                 close(pack_objects.err);
259                                 pack_objects.err = -1;
260                         }
261                         else
262                                 goto fail;
263                 }
264         }
265
266         if (finish_command(&pack_objects)) {
267                 error("git-upload-pack: git-pack-objects died with error.");
268                 goto fail;
269         }
270         if (finish_async(&rev_list))
271                 goto fail;      /* error was already reported */
272
273         /* flush the data */
274         if (0 <= buffered) {
275                 data[0] = buffered;
276                 sz = send_client_data(1, data, 1);
277                 if (sz < 0)
278                         goto fail;
279                 fprintf(stderr, "flushed.\n");
280         }
281         if (use_sideband)
282                 packet_flush(1);
283         return;
284
285  fail:
286         send_client_data(3, abort_msg, sizeof(abort_msg));
287         die("git-upload-pack: %s", abort_msg);
288 }
289
290 static int got_sha1(char *hex, unsigned char *sha1)
291 {
292         struct object *o;
293         int we_knew_they_have = 0;
294
295         if (get_sha1_hex(hex, sha1))
296                 die("git-upload-pack: expected SHA1 object, got '%s'", hex);
297         if (!has_sha1_file(sha1))
298                 return -1;
299
300         o = lookup_object(sha1);
301         if (!(o && o->parsed))
302                 o = parse_object(sha1);
303         if (!o)
304                 die("oops (%s)", sha1_to_hex(sha1));
305         if (o->type == OBJ_COMMIT) {
306                 struct commit_list *parents;
307                 struct commit *commit = (struct commit *)o;
308                 if (o->flags & THEY_HAVE)
309                         we_knew_they_have = 1;
310                 else
311                         o->flags |= THEY_HAVE;
312                 if (!oldest_have || (commit->date < oldest_have))
313                         oldest_have = commit->date;
314                 for (parents = commit->parents;
315                      parents;
316                      parents = parents->next)
317                         parents->item->object.flags |= THEY_HAVE;
318         }
319         if (!we_knew_they_have) {
320                 add_object_array(o, NULL, &have_obj);
321                 return 1;
322         }
323         return 0;
324 }
325
326 static int reachable(struct commit *want)
327 {
328         struct commit_list *work = NULL;
329
330         insert_by_date(want, &work);
331         while (work) {
332                 struct commit_list *list = work->next;
333                 struct commit *commit = work->item;
334                 free(work);
335                 work = list;
336
337                 if (commit->object.flags & THEY_HAVE) {
338                         want->object.flags |= COMMON_KNOWN;
339                         break;
340                 }
341                 if (!commit->object.parsed)
342                         parse_object(commit->object.sha1);
343                 if (commit->object.flags & REACHABLE)
344                         continue;
345                 commit->object.flags |= REACHABLE;
346                 if (commit->date < oldest_have)
347                         continue;
348                 for (list = commit->parents; list; list = list->next) {
349                         struct commit *parent = list->item;
350                         if (!(parent->object.flags & REACHABLE))
351                                 insert_by_date(parent, &work);
352                 }
353         }
354         want->object.flags |= REACHABLE;
355         clear_commit_marks(want, REACHABLE);
356         free_commit_list(work);
357         return (want->object.flags & COMMON_KNOWN);
358 }
359
360 static int ok_to_give_up(void)
361 {
362         int i;
363
364         if (!have_obj.nr)
365                 return 0;
366
367         for (i = 0; i < want_obj.nr; i++) {
368                 struct object *want = want_obj.objects[i].item;
369
370                 if (want->flags & COMMON_KNOWN)
371                         continue;
372                 want = deref_tag(want, "a want line", 0);
373                 if (!want || want->type != OBJ_COMMIT) {
374                         /* no way to tell if this is reachable by
375                          * looking at the ancestry chain alone, so
376                          * leave a note to ourselves not to worry about
377                          * this object anymore.
378                          */
379                         want_obj.objects[i].item->flags |= COMMON_KNOWN;
380                         continue;
381                 }
382                 if (!reachable((struct commit *)want))
383                         return 0;
384         }
385         return 1;
386 }
387
388 static int get_common_commits(void)
389 {
390         static char line[1000];
391         unsigned char sha1[20];
392         char hex[41], last_hex[41];
393         int len;
394
395         track_object_refs = 0;
396         save_commit_buffer = 0;
397
398         for(;;) {
399                 len = packet_read_line(0, line, sizeof(line));
400                 reset_timeout();
401
402                 if (!len) {
403                         if (have_obj.nr == 0 || multi_ack)
404                                 packet_write(1, "NAK\n");
405                         continue;
406                 }
407                 len = strip(line, len);
408                 if (!prefixcmp(line, "have ")) {
409                         switch (got_sha1(line+5, sha1)) {
410                         case -1: /* they have what we do not */
411                                 if (multi_ack && ok_to_give_up())
412                                         packet_write(1, "ACK %s continue\n",
413                                                      sha1_to_hex(sha1));
414                                 break;
415                         default:
416                                 memcpy(hex, sha1_to_hex(sha1), 41);
417                                 if (multi_ack) {
418                                         const char *msg = "ACK %s continue\n";
419                                         packet_write(1, msg, hex);
420                                         memcpy(last_hex, hex, 41);
421                                 }
422                                 else if (have_obj.nr == 1)
423                                         packet_write(1, "ACK %s\n", hex);
424                                 break;
425                         }
426                         continue;
427                 }
428                 if (!strcmp(line, "done")) {
429                         if (have_obj.nr > 0) {
430                                 if (multi_ack)
431                                         packet_write(1, "ACK %s\n", last_hex);
432                                 return 0;
433                         }
434                         packet_write(1, "NAK\n");
435                         return -1;
436                 }
437                 die("git-upload-pack: expected SHA1 list, got '%s'", line);
438         }
439 }
440
441 static void receive_needs(void)
442 {
443         struct object_array shallows = {0, 0, NULL};
444         static char line[1000];
445         int len, depth = 0;
446
447         for (;;) {
448                 struct object *o;
449                 unsigned char sha1_buf[20];
450                 len = packet_read_line(0, line, sizeof(line));
451                 reset_timeout();
452                 if (!len)
453                         break;
454
455                 if (!prefixcmp(line, "shallow ")) {
456                         unsigned char sha1[20];
457                         struct object *object;
458                         use_thin_pack = 0;
459                         if (get_sha1(line + 8, sha1))
460                                 die("invalid shallow line: %s", line);
461                         object = parse_object(sha1);
462                         if (!object)
463                                 die("did not find object for %s", line);
464                         object->flags |= CLIENT_SHALLOW;
465                         add_object_array(object, NULL, &shallows);
466                         continue;
467                 }
468                 if (!prefixcmp(line, "deepen ")) {
469                         char *end;
470                         use_thin_pack = 0;
471                         depth = strtol(line + 7, &end, 0);
472                         if (end == line + 7 || depth <= 0)
473                                 die("Invalid deepen: %s", line);
474                         continue;
475                 }
476                 if (prefixcmp(line, "want ") ||
477                     get_sha1_hex(line+5, sha1_buf))
478                         die("git-upload-pack: protocol error, "
479                             "expected to get sha, not '%s'", line);
480                 if (strstr(line+45, "multi_ack"))
481                         multi_ack = 1;
482                 if (strstr(line+45, "thin-pack"))
483                         use_thin_pack = 1;
484                 if (strstr(line+45, "ofs-delta"))
485                         use_ofs_delta = 1;
486                 if (strstr(line+45, "side-band-64k"))
487                         use_sideband = LARGE_PACKET_MAX;
488                 else if (strstr(line+45, "side-band"))
489                         use_sideband = DEFAULT_PACKET_MAX;
490                 if (strstr(line+45, "no-progress"))
491                         no_progress = 1;
492
493                 /* We have sent all our refs already, and the other end
494                  * should have chosen out of them; otherwise they are
495                  * asking for nonsense.
496                  *
497                  * Hmph.  We may later want to allow "want" line that
498                  * asks for something like "master~10" (symbolic)...
499                  * would it make sense?  I don't know.
500                  */
501                 o = lookup_object(sha1_buf);
502                 if (!o || !(o->flags & OUR_REF))
503                         die("git-upload-pack: not our ref %s", line+5);
504                 if (!(o->flags & WANTED)) {
505                         o->flags |= WANTED;
506                         add_object_array(o, NULL, &want_obj);
507                 }
508         }
509         if (depth == 0 && shallows.nr == 0)
510                 return;
511         if (depth > 0) {
512                 struct commit_list *result, *backup;
513                 int i;
514                 backup = result = get_shallow_commits(&want_obj, depth,
515                         SHALLOW, NOT_SHALLOW);
516                 while (result) {
517                         struct object *object = &result->item->object;
518                         if (!(object->flags & (CLIENT_SHALLOW|NOT_SHALLOW))) {
519                                 packet_write(1, "shallow %s",
520                                                 sha1_to_hex(object->sha1));
521                                 register_shallow(object->sha1);
522                         }
523                         result = result->next;
524                 }
525                 free_commit_list(backup);
526                 for (i = 0; i < shallows.nr; i++) {
527                         struct object *object = shallows.objects[i].item;
528                         if (object->flags & NOT_SHALLOW) {
529                                 struct commit_list *parents;
530                                 packet_write(1, "unshallow %s",
531                                         sha1_to_hex(object->sha1));
532                                 object->flags &= ~CLIENT_SHALLOW;
533                                 /* make sure the real parents are parsed */
534                                 unregister_shallow(object->sha1);
535                                 object->parsed = 0;
536                                 parse_commit((struct commit *)object);
537                                 parents = ((struct commit *)object)->parents;
538                                 while (parents) {
539                                         add_object_array(&parents->item->object,
540                                                         NULL, &want_obj);
541                                         parents = parents->next;
542                                 }
543                         }
544                         /* make sure commit traversal conforms to client */
545                         register_shallow(object->sha1);
546                 }
547                 packet_flush(1);
548         } else
549                 if (shallows.nr > 0) {
550                         int i;
551                         for (i = 0; i < shallows.nr; i++)
552                                 register_shallow(shallows.objects[i].item->sha1);
553                 }
554         free(shallows.objects);
555 }
556
557 static int send_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
558 {
559         static const char *capabilities = "multi_ack thin-pack side-band"
560                 " side-band-64k ofs-delta shallow no-progress";
561         struct object *o = parse_object(sha1);
562
563         if (!o)
564                 die("git-upload-pack: cannot find object %s:", sha1_to_hex(sha1));
565
566         if (capabilities)
567                 packet_write(1, "%s %s%c%s\n", sha1_to_hex(sha1), refname,
568                         0, capabilities);
569         else
570                 packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname);
571         capabilities = NULL;
572         if (!(o->flags & OUR_REF)) {
573                 o->flags |= OUR_REF;
574                 nr_our_refs++;
575         }
576         if (o->type == OBJ_TAG) {
577                 o = deref_tag(o, refname, 0);
578                 packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname);
579         }
580         return 0;
581 }
582
583 static void upload_pack(void)
584 {
585         reset_timeout();
586         head_ref(send_ref, NULL);
587         for_each_ref(send_ref, NULL);
588         packet_flush(1);
589         receive_needs();
590         if (want_obj.nr) {
591                 get_common_commits();
592                 create_pack_file();
593         }
594 }
595
596 int main(int argc, char **argv)
597 {
598         char *dir;
599         int i;
600         int strict = 0;
601
602         for (i = 1; i < argc; i++) {
603                 char *arg = argv[i];
604
605                 if (arg[0] != '-')
606                         break;
607                 if (!strcmp(arg, "--strict")) {
608                         strict = 1;
609                         continue;
610                 }
611                 if (!prefixcmp(arg, "--timeout=")) {
612                         timeout = atoi(arg+10);
613                         continue;
614                 }
615                 if (!strcmp(arg, "--")) {
616                         i++;
617                         break;
618                 }
619         }
620
621         if (i != argc-1)
622                 usage(upload_pack_usage);
623         dir = argv[i];
624
625         if (!enter_repo(dir, strict))
626                 die("'%s': unable to chdir or not a git archive", dir);
627         if (is_repository_shallow())
628                 die("attempt to fetch/clone from a shallow repository");
629         upload_pack();
630         return 0;
631 }