Git 2.16.2
[git] / builtin / receive-pack.c
1 #include "builtin.h"
2 #include "config.h"
3 #include "lockfile.h"
4 #include "pack.h"
5 #include "refs.h"
6 #include "pkt-line.h"
7 #include "sideband.h"
8 #include "run-command.h"
9 #include "exec_cmd.h"
10 #include "commit.h"
11 #include "object.h"
12 #include "remote.h"
13 #include "connect.h"
14 #include "transport.h"
15 #include "string-list.h"
16 #include "sha1-array.h"
17 #include "connected.h"
18 #include "argv-array.h"
19 #include "version.h"
20 #include "tag.h"
21 #include "gpg-interface.h"
22 #include "sigchain.h"
23 #include "fsck.h"
24 #include "tmp-objdir.h"
25 #include "oidset.h"
26 #include "packfile.h"
27 #include "protocol.h"
28
29 static const char * const receive_pack_usage[] = {
30         N_("git receive-pack <git-dir>"),
31         NULL
32 };
33
34 enum deny_action {
35         DENY_UNCONFIGURED,
36         DENY_IGNORE,
37         DENY_WARN,
38         DENY_REFUSE,
39         DENY_UPDATE_INSTEAD
40 };
41
42 static int deny_deletes;
43 static int deny_non_fast_forwards;
44 static enum deny_action deny_current_branch = DENY_UNCONFIGURED;
45 static enum deny_action deny_delete_current = DENY_UNCONFIGURED;
46 static int receive_fsck_objects = -1;
47 static int transfer_fsck_objects = -1;
48 static struct strbuf fsck_msg_types = STRBUF_INIT;
49 static int receive_unpack_limit = -1;
50 static int transfer_unpack_limit = -1;
51 static int advertise_atomic_push = 1;
52 static int advertise_push_options;
53 static int unpack_limit = 100;
54 static off_t max_input_size;
55 static int report_status;
56 static int use_sideband;
57 static int use_atomic;
58 static int use_push_options;
59 static int quiet;
60 static int prefer_ofs_delta = 1;
61 static int auto_update_server_info;
62 static int auto_gc = 1;
63 static int reject_thin;
64 static int stateless_rpc;
65 static const char *service_dir;
66 static const char *head_name;
67 static void *head_name_to_free;
68 static int sent_capabilities;
69 static int shallow_update;
70 static const char *alt_shallow_file;
71 static struct strbuf push_cert = STRBUF_INIT;
72 static unsigned char push_cert_sha1[20];
73 static struct signature_check sigcheck;
74 static const char *push_cert_nonce;
75 static const char *cert_nonce_seed;
76
77 static const char *NONCE_UNSOLICITED = "UNSOLICITED";
78 static const char *NONCE_BAD = "BAD";
79 static const char *NONCE_MISSING = "MISSING";
80 static const char *NONCE_OK = "OK";
81 static const char *NONCE_SLOP = "SLOP";
82 static const char *nonce_status;
83 static long nonce_stamp_slop;
84 static timestamp_t nonce_stamp_slop_limit;
85 static struct ref_transaction *transaction;
86
87 static enum {
88         KEEPALIVE_NEVER = 0,
89         KEEPALIVE_AFTER_NUL,
90         KEEPALIVE_ALWAYS
91 } use_keepalive;
92 static int keepalive_in_sec = 5;
93
94 static struct tmp_objdir *tmp_objdir;
95
96 static enum deny_action parse_deny_action(const char *var, const char *value)
97 {
98         if (value) {
99                 if (!strcasecmp(value, "ignore"))
100                         return DENY_IGNORE;
101                 if (!strcasecmp(value, "warn"))
102                         return DENY_WARN;
103                 if (!strcasecmp(value, "refuse"))
104                         return DENY_REFUSE;
105                 if (!strcasecmp(value, "updateinstead"))
106                         return DENY_UPDATE_INSTEAD;
107         }
108         if (git_config_bool(var, value))
109                 return DENY_REFUSE;
110         return DENY_IGNORE;
111 }
112
113 static int receive_pack_config(const char *var, const char *value, void *cb)
114 {
115         int status = parse_hide_refs_config(var, value, "receive");
116
117         if (status)
118                 return status;
119
120         if (strcmp(var, "receive.denydeletes") == 0) {
121                 deny_deletes = git_config_bool(var, value);
122                 return 0;
123         }
124
125         if (strcmp(var, "receive.denynonfastforwards") == 0) {
126                 deny_non_fast_forwards = git_config_bool(var, value);
127                 return 0;
128         }
129
130         if (strcmp(var, "receive.unpacklimit") == 0) {
131                 receive_unpack_limit = git_config_int(var, value);
132                 return 0;
133         }
134
135         if (strcmp(var, "transfer.unpacklimit") == 0) {
136                 transfer_unpack_limit = git_config_int(var, value);
137                 return 0;
138         }
139
140         if (strcmp(var, "receive.fsck.skiplist") == 0) {
141                 const char *path;
142
143                 if (git_config_pathname(&path, var, value))
144                         return 1;
145                 strbuf_addf(&fsck_msg_types, "%cskiplist=%s",
146                         fsck_msg_types.len ? ',' : '=', path);
147                 free((char *)path);
148                 return 0;
149         }
150
151         if (skip_prefix(var, "receive.fsck.", &var)) {
152                 if (is_valid_msg_type(var, value))
153                         strbuf_addf(&fsck_msg_types, "%c%s=%s",
154                                 fsck_msg_types.len ? ',' : '=', var, value);
155                 else
156                         warning("Skipping unknown msg id '%s'", var);
157                 return 0;
158         }
159
160         if (strcmp(var, "receive.fsckobjects") == 0) {
161                 receive_fsck_objects = git_config_bool(var, value);
162                 return 0;
163         }
164
165         if (strcmp(var, "transfer.fsckobjects") == 0) {
166                 transfer_fsck_objects = git_config_bool(var, value);
167                 return 0;
168         }
169
170         if (!strcmp(var, "receive.denycurrentbranch")) {
171                 deny_current_branch = parse_deny_action(var, value);
172                 return 0;
173         }
174
175         if (strcmp(var, "receive.denydeletecurrent") == 0) {
176                 deny_delete_current = parse_deny_action(var, value);
177                 return 0;
178         }
179
180         if (strcmp(var, "repack.usedeltabaseoffset") == 0) {
181                 prefer_ofs_delta = git_config_bool(var, value);
182                 return 0;
183         }
184
185         if (strcmp(var, "receive.updateserverinfo") == 0) {
186                 auto_update_server_info = git_config_bool(var, value);
187                 return 0;
188         }
189
190         if (strcmp(var, "receive.autogc") == 0) {
191                 auto_gc = git_config_bool(var, value);
192                 return 0;
193         }
194
195         if (strcmp(var, "receive.shallowupdate") == 0) {
196                 shallow_update = git_config_bool(var, value);
197                 return 0;
198         }
199
200         if (strcmp(var, "receive.certnonceseed") == 0)
201                 return git_config_string(&cert_nonce_seed, var, value);
202
203         if (strcmp(var, "receive.certnonceslop") == 0) {
204                 nonce_stamp_slop_limit = git_config_ulong(var, value);
205                 return 0;
206         }
207
208         if (strcmp(var, "receive.advertiseatomic") == 0) {
209                 advertise_atomic_push = git_config_bool(var, value);
210                 return 0;
211         }
212
213         if (strcmp(var, "receive.advertisepushoptions") == 0) {
214                 advertise_push_options = git_config_bool(var, value);
215                 return 0;
216         }
217
218         if (strcmp(var, "receive.keepalive") == 0) {
219                 keepalive_in_sec = git_config_int(var, value);
220                 return 0;
221         }
222
223         if (strcmp(var, "receive.maxinputsize") == 0) {
224                 max_input_size = git_config_int64(var, value);
225                 return 0;
226         }
227
228         return git_default_config(var, value, cb);
229 }
230
231 static void show_ref(const char *path, const struct object_id *oid)
232 {
233         if (sent_capabilities) {
234                 packet_write_fmt(1, "%s %s\n", oid_to_hex(oid), path);
235         } else {
236                 struct strbuf cap = STRBUF_INIT;
237
238                 strbuf_addstr(&cap,
239                               "report-status delete-refs side-band-64k quiet");
240                 if (advertise_atomic_push)
241                         strbuf_addstr(&cap, " atomic");
242                 if (prefer_ofs_delta)
243                         strbuf_addstr(&cap, " ofs-delta");
244                 if (push_cert_nonce)
245                         strbuf_addf(&cap, " push-cert=%s", push_cert_nonce);
246                 if (advertise_push_options)
247                         strbuf_addstr(&cap, " push-options");
248                 strbuf_addf(&cap, " agent=%s", git_user_agent_sanitized());
249                 packet_write_fmt(1, "%s %s%c%s\n",
250                              oid_to_hex(oid), path, 0, cap.buf);
251                 strbuf_release(&cap);
252                 sent_capabilities = 1;
253         }
254 }
255
256 static int show_ref_cb(const char *path_full, const struct object_id *oid,
257                        int flag, void *data)
258 {
259         struct oidset *seen = data;
260         const char *path = strip_namespace(path_full);
261
262         if (ref_is_hidden(path, path_full))
263                 return 0;
264
265         /*
266          * Advertise refs outside our current namespace as ".have"
267          * refs, so that the client can use them to minimize data
268          * transfer but will otherwise ignore them.
269          */
270         if (!path) {
271                 if (oidset_insert(seen, oid))
272                         return 0;
273                 path = ".have";
274         } else {
275                 oidset_insert(seen, oid);
276         }
277         show_ref(path, oid);
278         return 0;
279 }
280
281 static void show_one_alternate_ref(const char *refname,
282                                    const struct object_id *oid,
283                                    void *data)
284 {
285         struct oidset *seen = data;
286
287         if (oidset_insert(seen, oid))
288                 return;
289
290         show_ref(".have", oid);
291 }
292
293 static void write_head_info(void)
294 {
295         static struct oidset seen = OIDSET_INIT;
296
297         for_each_ref(show_ref_cb, &seen);
298         for_each_alternate_ref(show_one_alternate_ref, &seen);
299         oidset_clear(&seen);
300         if (!sent_capabilities)
301                 show_ref("capabilities^{}", &null_oid);
302
303         advertise_shallow_grafts(1);
304
305         /* EOF */
306         packet_flush(1);
307 }
308
309 struct command {
310         struct command *next;
311         const char *error_string;
312         unsigned int skip_update:1,
313                      did_not_exist:1;
314         int index;
315         struct object_id old_oid;
316         struct object_id new_oid;
317         char ref_name[FLEX_ARRAY]; /* more */
318 };
319
320 static void rp_error(const char *err, ...) __attribute__((format (printf, 1, 2)));
321 static void rp_warning(const char *err, ...) __attribute__((format (printf, 1, 2)));
322
323 static void report_message(const char *prefix, const char *err, va_list params)
324 {
325         int sz;
326         char msg[4096];
327
328         sz = xsnprintf(msg, sizeof(msg), "%s", prefix);
329         sz += vsnprintf(msg + sz, sizeof(msg) - sz, err, params);
330         if (sz > (sizeof(msg) - 1))
331                 sz = sizeof(msg) - 1;
332         msg[sz++] = '\n';
333
334         if (use_sideband)
335                 send_sideband(1, 2, msg, sz, use_sideband);
336         else
337                 xwrite(2, msg, sz);
338 }
339
340 static void rp_warning(const char *err, ...)
341 {
342         va_list params;
343         va_start(params, err);
344         report_message("warning: ", err, params);
345         va_end(params);
346 }
347
348 static void rp_error(const char *err, ...)
349 {
350         va_list params;
351         va_start(params, err);
352         report_message("error: ", err, params);
353         va_end(params);
354 }
355
356 static int copy_to_sideband(int in, int out, void *arg)
357 {
358         char data[128];
359         int keepalive_active = 0;
360
361         if (keepalive_in_sec <= 0)
362                 use_keepalive = KEEPALIVE_NEVER;
363         if (use_keepalive == KEEPALIVE_ALWAYS)
364                 keepalive_active = 1;
365
366         while (1) {
367                 ssize_t sz;
368
369                 if (keepalive_active) {
370                         struct pollfd pfd;
371                         int ret;
372
373                         pfd.fd = in;
374                         pfd.events = POLLIN;
375                         ret = poll(&pfd, 1, 1000 * keepalive_in_sec);
376
377                         if (ret < 0) {
378                                 if (errno == EINTR)
379                                         continue;
380                                 else
381                                         break;
382                         } else if (ret == 0) {
383                                 /* no data; send a keepalive packet */
384                                 static const char buf[] = "0005\1";
385                                 write_or_die(1, buf, sizeof(buf) - 1);
386                                 continue;
387                         } /* else there is actual data to read */
388                 }
389
390                 sz = xread(in, data, sizeof(data));
391                 if (sz <= 0)
392                         break;
393
394                 if (use_keepalive == KEEPALIVE_AFTER_NUL && !keepalive_active) {
395                         const char *p = memchr(data, '\0', sz);
396                         if (p) {
397                                 /*
398                                  * The NUL tells us to start sending keepalives. Make
399                                  * sure we send any other data we read along
400                                  * with it.
401                                  */
402                                 keepalive_active = 1;
403                                 send_sideband(1, 2, data, p - data, use_sideband);
404                                 send_sideband(1, 2, p + 1, sz - (p - data + 1), use_sideband);
405                                 continue;
406                         }
407                 }
408
409                 /*
410                  * Either we're not looking for a NUL signal, or we didn't see
411                  * it yet; just pass along the data.
412                  */
413                 send_sideband(1, 2, data, sz, use_sideband);
414         }
415         close(in);
416         return 0;
417 }
418
419 #define HMAC_BLOCK_SIZE 64
420
421 static void hmac_sha1(unsigned char *out,
422                       const char *key_in, size_t key_len,
423                       const char *text, size_t text_len)
424 {
425         unsigned char key[HMAC_BLOCK_SIZE];
426         unsigned char k_ipad[HMAC_BLOCK_SIZE];
427         unsigned char k_opad[HMAC_BLOCK_SIZE];
428         int i;
429         git_SHA_CTX ctx;
430
431         /* RFC 2104 2. (1) */
432         memset(key, '\0', HMAC_BLOCK_SIZE);
433         if (HMAC_BLOCK_SIZE < key_len) {
434                 git_SHA1_Init(&ctx);
435                 git_SHA1_Update(&ctx, key_in, key_len);
436                 git_SHA1_Final(key, &ctx);
437         } else {
438                 memcpy(key, key_in, key_len);
439         }
440
441         /* RFC 2104 2. (2) & (5) */
442         for (i = 0; i < sizeof(key); i++) {
443                 k_ipad[i] = key[i] ^ 0x36;
444                 k_opad[i] = key[i] ^ 0x5c;
445         }
446
447         /* RFC 2104 2. (3) & (4) */
448         git_SHA1_Init(&ctx);
449         git_SHA1_Update(&ctx, k_ipad, sizeof(k_ipad));
450         git_SHA1_Update(&ctx, text, text_len);
451         git_SHA1_Final(out, &ctx);
452
453         /* RFC 2104 2. (6) & (7) */
454         git_SHA1_Init(&ctx);
455         git_SHA1_Update(&ctx, k_opad, sizeof(k_opad));
456         git_SHA1_Update(&ctx, out, 20);
457         git_SHA1_Final(out, &ctx);
458 }
459
460 static char *prepare_push_cert_nonce(const char *path, timestamp_t stamp)
461 {
462         struct strbuf buf = STRBUF_INIT;
463         unsigned char sha1[20];
464
465         strbuf_addf(&buf, "%s:%"PRItime, path, stamp);
466         hmac_sha1(sha1, buf.buf, buf.len, cert_nonce_seed, strlen(cert_nonce_seed));;
467         strbuf_release(&buf);
468
469         /* RFC 2104 5. HMAC-SHA1-80 */
470         strbuf_addf(&buf, "%"PRItime"-%.*s", stamp, 20, sha1_to_hex(sha1));
471         return strbuf_detach(&buf, NULL);
472 }
473
474 /*
475  * NEEDSWORK: reuse find_commit_header() from jk/commit-author-parsing
476  * after dropping "_commit" from its name and possibly moving it out
477  * of commit.c
478  */
479 static char *find_header(const char *msg, size_t len, const char *key,
480                          const char **next_line)
481 {
482         int key_len = strlen(key);
483         const char *line = msg;
484
485         while (line && line < msg + len) {
486                 const char *eol = strchrnul(line, '\n');
487
488                 if ((msg + len <= eol) || line == eol)
489                         return NULL;
490                 if (line + key_len < eol &&
491                     !memcmp(line, key, key_len) && line[key_len] == ' ') {
492                         int offset = key_len + 1;
493                         if (next_line)
494                                 *next_line = *eol ? eol + 1 : eol;
495                         return xmemdupz(line + offset, (eol - line) - offset);
496                 }
497                 line = *eol ? eol + 1 : NULL;
498         }
499         return NULL;
500 }
501
502 static const char *check_nonce(const char *buf, size_t len)
503 {
504         char *nonce = find_header(buf, len, "nonce", NULL);
505         timestamp_t stamp, ostamp;
506         char *bohmac, *expect = NULL;
507         const char *retval = NONCE_BAD;
508
509         if (!nonce) {
510                 retval = NONCE_MISSING;
511                 goto leave;
512         } else if (!push_cert_nonce) {
513                 retval = NONCE_UNSOLICITED;
514                 goto leave;
515         } else if (!strcmp(push_cert_nonce, nonce)) {
516                 retval = NONCE_OK;
517                 goto leave;
518         }
519
520         if (!stateless_rpc) {
521                 /* returned nonce MUST match what we gave out earlier */
522                 retval = NONCE_BAD;
523                 goto leave;
524         }
525
526         /*
527          * In stateless mode, we may be receiving a nonce issued by
528          * another instance of the server that serving the same
529          * repository, and the timestamps may not match, but the
530          * nonce-seed and dir should match, so we can recompute and
531          * report the time slop.
532          *
533          * In addition, when a nonce issued by another instance has
534          * timestamp within receive.certnonceslop seconds, we pretend
535          * as if we issued that nonce when reporting to the hook.
536          */
537
538         /* nonce is concat(<seconds-since-epoch>, "-", <hmac>) */
539         if (*nonce <= '0' || '9' < *nonce) {
540                 retval = NONCE_BAD;
541                 goto leave;
542         }
543         stamp = parse_timestamp(nonce, &bohmac, 10);
544         if (bohmac == nonce || bohmac[0] != '-') {
545                 retval = NONCE_BAD;
546                 goto leave;
547         }
548
549         expect = prepare_push_cert_nonce(service_dir, stamp);
550         if (strcmp(expect, nonce)) {
551                 /* Not what we would have signed earlier */
552                 retval = NONCE_BAD;
553                 goto leave;
554         }
555
556         /*
557          * By how many seconds is this nonce stale?  Negative value
558          * would mean it was issued by another server with its clock
559          * skewed in the future.
560          */
561         ostamp = parse_timestamp(push_cert_nonce, NULL, 10);
562         nonce_stamp_slop = (long)ostamp - (long)stamp;
563
564         if (nonce_stamp_slop_limit &&
565             labs(nonce_stamp_slop) <= nonce_stamp_slop_limit) {
566                 /*
567                  * Pretend as if the received nonce (which passes the
568                  * HMAC check, so it is not a forged by third-party)
569                  * is what we issued.
570                  */
571                 free((void *)push_cert_nonce);
572                 push_cert_nonce = xstrdup(nonce);
573                 retval = NONCE_OK;
574         } else {
575                 retval = NONCE_SLOP;
576         }
577
578 leave:
579         free(nonce);
580         free(expect);
581         return retval;
582 }
583
584 /*
585  * Return 1 if there is no push_cert or if the push options in push_cert are
586  * the same as those in the argument; 0 otherwise.
587  */
588 static int check_cert_push_options(const struct string_list *push_options)
589 {
590         const char *buf = push_cert.buf;
591         int len = push_cert.len;
592
593         char *option;
594         const char *next_line;
595         int options_seen = 0;
596
597         int retval = 1;
598
599         if (!len)
600                 return 1;
601
602         while ((option = find_header(buf, len, "push-option", &next_line))) {
603                 len -= (next_line - buf);
604                 buf = next_line;
605                 options_seen++;
606                 if (options_seen > push_options->nr
607                     || strcmp(option,
608                               push_options->items[options_seen - 1].string)) {
609                         retval = 0;
610                         goto leave;
611                 }
612                 free(option);
613         }
614
615         if (options_seen != push_options->nr)
616                 retval = 0;
617
618 leave:
619         free(option);
620         return retval;
621 }
622
623 static void prepare_push_cert_sha1(struct child_process *proc)
624 {
625         static int already_done;
626
627         if (!push_cert.len)
628                 return;
629
630         if (!already_done) {
631                 struct strbuf gpg_output = STRBUF_INIT;
632                 struct strbuf gpg_status = STRBUF_INIT;
633                 int bogs /* beginning_of_gpg_sig */;
634
635                 already_done = 1;
636                 if (write_sha1_file(push_cert.buf, push_cert.len, "blob", push_cert_sha1))
637                         hashclr(push_cert_sha1);
638
639                 memset(&sigcheck, '\0', sizeof(sigcheck));
640                 sigcheck.result = 'N';
641
642                 bogs = parse_signature(push_cert.buf, push_cert.len);
643                 if (verify_signed_buffer(push_cert.buf, bogs,
644                                          push_cert.buf + bogs, push_cert.len - bogs,
645                                          &gpg_output, &gpg_status) < 0) {
646                         ; /* error running gpg */
647                 } else {
648                         sigcheck.payload = push_cert.buf;
649                         sigcheck.gpg_output = gpg_output.buf;
650                         sigcheck.gpg_status = gpg_status.buf;
651                         parse_gpg_output(&sigcheck);
652                 }
653
654                 strbuf_release(&gpg_output);
655                 strbuf_release(&gpg_status);
656                 nonce_status = check_nonce(push_cert.buf, bogs);
657         }
658         if (!is_null_sha1(push_cert_sha1)) {
659                 argv_array_pushf(&proc->env_array, "GIT_PUSH_CERT=%s",
660                                  sha1_to_hex(push_cert_sha1));
661                 argv_array_pushf(&proc->env_array, "GIT_PUSH_CERT_SIGNER=%s",
662                                  sigcheck.signer ? sigcheck.signer : "");
663                 argv_array_pushf(&proc->env_array, "GIT_PUSH_CERT_KEY=%s",
664                                  sigcheck.key ? sigcheck.key : "");
665                 argv_array_pushf(&proc->env_array, "GIT_PUSH_CERT_STATUS=%c",
666                                  sigcheck.result);
667                 if (push_cert_nonce) {
668                         argv_array_pushf(&proc->env_array,
669                                          "GIT_PUSH_CERT_NONCE=%s",
670                                          push_cert_nonce);
671                         argv_array_pushf(&proc->env_array,
672                                          "GIT_PUSH_CERT_NONCE_STATUS=%s",
673                                          nonce_status);
674                         if (nonce_status == NONCE_SLOP)
675                                 argv_array_pushf(&proc->env_array,
676                                                  "GIT_PUSH_CERT_NONCE_SLOP=%ld",
677                                                  nonce_stamp_slop);
678                 }
679         }
680 }
681
682 struct receive_hook_feed_state {
683         struct command *cmd;
684         int skip_broken;
685         struct strbuf buf;
686         const struct string_list *push_options;
687 };
688
689 typedef int (*feed_fn)(void *, const char **, size_t *);
690 static int run_and_feed_hook(const char *hook_name, feed_fn feed,
691                              struct receive_hook_feed_state *feed_state)
692 {
693         struct child_process proc = CHILD_PROCESS_INIT;
694         struct async muxer;
695         const char *argv[2];
696         int code;
697
698         argv[0] = find_hook(hook_name);
699         if (!argv[0])
700                 return 0;
701
702         argv[1] = NULL;
703
704         proc.argv = argv;
705         proc.in = -1;
706         proc.stdout_to_stderr = 1;
707         if (feed_state->push_options) {
708                 int i;
709                 for (i = 0; i < feed_state->push_options->nr; i++)
710                         argv_array_pushf(&proc.env_array,
711                                 "GIT_PUSH_OPTION_%d=%s", i,
712                                 feed_state->push_options->items[i].string);
713                 argv_array_pushf(&proc.env_array, "GIT_PUSH_OPTION_COUNT=%d",
714                                  feed_state->push_options->nr);
715         } else
716                 argv_array_pushf(&proc.env_array, "GIT_PUSH_OPTION_COUNT");
717
718         if (tmp_objdir)
719                 argv_array_pushv(&proc.env_array, tmp_objdir_env(tmp_objdir));
720
721         if (use_sideband) {
722                 memset(&muxer, 0, sizeof(muxer));
723                 muxer.proc = copy_to_sideband;
724                 muxer.in = -1;
725                 code = start_async(&muxer);
726                 if (code)
727                         return code;
728                 proc.err = muxer.in;
729         }
730
731         prepare_push_cert_sha1(&proc);
732
733         code = start_command(&proc);
734         if (code) {
735                 if (use_sideband)
736                         finish_async(&muxer);
737                 return code;
738         }
739
740         sigchain_push(SIGPIPE, SIG_IGN);
741
742         while (1) {
743                 const char *buf;
744                 size_t n;
745                 if (feed(feed_state, &buf, &n))
746                         break;
747                 if (write_in_full(proc.in, buf, n) < 0)
748                         break;
749         }
750         close(proc.in);
751         if (use_sideband)
752                 finish_async(&muxer);
753
754         sigchain_pop(SIGPIPE);
755
756         return finish_command(&proc);
757 }
758
759 static int feed_receive_hook(void *state_, const char **bufp, size_t *sizep)
760 {
761         struct receive_hook_feed_state *state = state_;
762         struct command *cmd = state->cmd;
763
764         while (cmd &&
765                state->skip_broken && (cmd->error_string || cmd->did_not_exist))
766                 cmd = cmd->next;
767         if (!cmd)
768                 return -1; /* EOF */
769         strbuf_reset(&state->buf);
770         strbuf_addf(&state->buf, "%s %s %s\n",
771                     oid_to_hex(&cmd->old_oid), oid_to_hex(&cmd->new_oid),
772                     cmd->ref_name);
773         state->cmd = cmd->next;
774         if (bufp) {
775                 *bufp = state->buf.buf;
776                 *sizep = state->buf.len;
777         }
778         return 0;
779 }
780
781 static int run_receive_hook(struct command *commands,
782                             const char *hook_name,
783                             int skip_broken,
784                             const struct string_list *push_options)
785 {
786         struct receive_hook_feed_state state;
787         int status;
788
789         strbuf_init(&state.buf, 0);
790         state.cmd = commands;
791         state.skip_broken = skip_broken;
792         if (feed_receive_hook(&state, NULL, NULL))
793                 return 0;
794         state.cmd = commands;
795         state.push_options = push_options;
796         status = run_and_feed_hook(hook_name, feed_receive_hook, &state);
797         strbuf_release(&state.buf);
798         return status;
799 }
800
801 static int run_update_hook(struct command *cmd)
802 {
803         const char *argv[5];
804         struct child_process proc = CHILD_PROCESS_INIT;
805         int code;
806
807         argv[0] = find_hook("update");
808         if (!argv[0])
809                 return 0;
810
811         argv[1] = cmd->ref_name;
812         argv[2] = oid_to_hex(&cmd->old_oid);
813         argv[3] = oid_to_hex(&cmd->new_oid);
814         argv[4] = NULL;
815
816         proc.no_stdin = 1;
817         proc.stdout_to_stderr = 1;
818         proc.err = use_sideband ? -1 : 0;
819         proc.argv = argv;
820
821         code = start_command(&proc);
822         if (code)
823                 return code;
824         if (use_sideband)
825                 copy_to_sideband(proc.err, -1, NULL);
826         return finish_command(&proc);
827 }
828
829 static int is_ref_checked_out(const char *ref)
830 {
831         if (is_bare_repository())
832                 return 0;
833
834         if (!head_name)
835                 return 0;
836         return !strcmp(head_name, ref);
837 }
838
839 static char *refuse_unconfigured_deny_msg =
840         N_("By default, updating the current branch in a non-bare repository\n"
841            "is denied, because it will make the index and work tree inconsistent\n"
842            "with what you pushed, and will require 'git reset --hard' to match\n"
843            "the work tree to HEAD.\n"
844            "\n"
845            "You can set the 'receive.denyCurrentBranch' configuration variable\n"
846            "to 'ignore' or 'warn' in the remote repository to allow pushing into\n"
847            "its current branch; however, this is not recommended unless you\n"
848            "arranged to update its work tree to match what you pushed in some\n"
849            "other way.\n"
850            "\n"
851            "To squelch this message and still keep the default behaviour, set\n"
852            "'receive.denyCurrentBranch' configuration variable to 'refuse'.");
853
854 static void refuse_unconfigured_deny(void)
855 {
856         rp_error("%s", _(refuse_unconfigured_deny_msg));
857 }
858
859 static char *refuse_unconfigured_deny_delete_current_msg =
860         N_("By default, deleting the current branch is denied, because the next\n"
861            "'git clone' won't result in any file checked out, causing confusion.\n"
862            "\n"
863            "You can set 'receive.denyDeleteCurrent' configuration variable to\n"
864            "'warn' or 'ignore' in the remote repository to allow deleting the\n"
865            "current branch, with or without a warning message.\n"
866            "\n"
867            "To squelch this message, you can set it to 'refuse'.");
868
869 static void refuse_unconfigured_deny_delete_current(void)
870 {
871         rp_error("%s", _(refuse_unconfigured_deny_delete_current_msg));
872 }
873
874 static int command_singleton_iterator(void *cb_data, struct object_id *oid);
875 static int update_shallow_ref(struct command *cmd, struct shallow_info *si)
876 {
877         static struct lock_file shallow_lock;
878         struct oid_array extra = OID_ARRAY_INIT;
879         struct check_connected_options opt = CHECK_CONNECTED_INIT;
880         uint32_t mask = 1 << (cmd->index % 32);
881         int i;
882
883         trace_printf_key(&trace_shallow,
884                          "shallow: update_shallow_ref %s\n", cmd->ref_name);
885         for (i = 0; i < si->shallow->nr; i++)
886                 if (si->used_shallow[i] &&
887                     (si->used_shallow[i][cmd->index / 32] & mask) &&
888                     !delayed_reachability_test(si, i))
889                         oid_array_append(&extra, &si->shallow->oid[i]);
890
891         opt.env = tmp_objdir_env(tmp_objdir);
892         setup_alternate_shallow(&shallow_lock, &opt.shallow_file, &extra);
893         if (check_connected(command_singleton_iterator, cmd, &opt)) {
894                 rollback_lock_file(&shallow_lock);
895                 oid_array_clear(&extra);
896                 return -1;
897         }
898
899         commit_lock_file(&shallow_lock);
900
901         /*
902          * Make sure setup_alternate_shallow() for the next ref does
903          * not lose these new roots..
904          */
905         for (i = 0; i < extra.nr; i++)
906                 register_shallow(&extra.oid[i]);
907
908         si->shallow_ref[cmd->index] = 0;
909         oid_array_clear(&extra);
910         return 0;
911 }
912
913 /*
914  * NEEDSWORK: we should consolidate various implementions of "are we
915  * on an unborn branch?" test into one, and make the unified one more
916  * robust. !get_sha1() based check used here and elsewhere would not
917  * allow us to tell an unborn branch from corrupt ref, for example.
918  * For the purpose of fixing "deploy-to-update does not work when
919  * pushing into an empty repository" issue, this should suffice for
920  * now.
921  */
922 static int head_has_history(void)
923 {
924         struct object_id oid;
925
926         return !get_oid("HEAD", &oid);
927 }
928
929 static const char *push_to_deploy(unsigned char *sha1,
930                                   struct argv_array *env,
931                                   const char *work_tree)
932 {
933         const char *update_refresh[] = {
934                 "update-index", "-q", "--ignore-submodules", "--refresh", NULL
935         };
936         const char *diff_files[] = {
937                 "diff-files", "--quiet", "--ignore-submodules", "--", NULL
938         };
939         const char *diff_index[] = {
940                 "diff-index", "--quiet", "--cached", "--ignore-submodules",
941                 NULL, "--", NULL
942         };
943         const char *read_tree[] = {
944                 "read-tree", "-u", "-m", NULL, NULL
945         };
946         struct child_process child = CHILD_PROCESS_INIT;
947
948         child.argv = update_refresh;
949         child.env = env->argv;
950         child.dir = work_tree;
951         child.no_stdin = 1;
952         child.stdout_to_stderr = 1;
953         child.git_cmd = 1;
954         if (run_command(&child))
955                 return "Up-to-date check failed";
956
957         /* run_command() does not clean up completely; reinitialize */
958         child_process_init(&child);
959         child.argv = diff_files;
960         child.env = env->argv;
961         child.dir = work_tree;
962         child.no_stdin = 1;
963         child.stdout_to_stderr = 1;
964         child.git_cmd = 1;
965         if (run_command(&child))
966                 return "Working directory has unstaged changes";
967
968         /* diff-index with either HEAD or an empty tree */
969         diff_index[4] = head_has_history() ? "HEAD" : EMPTY_TREE_SHA1_HEX;
970
971         child_process_init(&child);
972         child.argv = diff_index;
973         child.env = env->argv;
974         child.no_stdin = 1;
975         child.no_stdout = 1;
976         child.stdout_to_stderr = 0;
977         child.git_cmd = 1;
978         if (run_command(&child))
979                 return "Working directory has staged changes";
980
981         read_tree[3] = sha1_to_hex(sha1);
982         child_process_init(&child);
983         child.argv = read_tree;
984         child.env = env->argv;
985         child.dir = work_tree;
986         child.no_stdin = 1;
987         child.no_stdout = 1;
988         child.stdout_to_stderr = 0;
989         child.git_cmd = 1;
990         if (run_command(&child))
991                 return "Could not update working tree to new HEAD";
992
993         return NULL;
994 }
995
996 static const char *push_to_checkout_hook = "push-to-checkout";
997
998 static const char *push_to_checkout(unsigned char *sha1,
999                                     struct argv_array *env,
1000                                     const char *work_tree)
1001 {
1002         argv_array_pushf(env, "GIT_WORK_TREE=%s", absolute_path(work_tree));
1003         if (run_hook_le(env->argv, push_to_checkout_hook,
1004                         sha1_to_hex(sha1), NULL))
1005                 return "push-to-checkout hook declined";
1006         else
1007                 return NULL;
1008 }
1009
1010 static const char *update_worktree(unsigned char *sha1)
1011 {
1012         const char *retval;
1013         const char *work_tree = git_work_tree_cfg ? git_work_tree_cfg : "..";
1014         struct argv_array env = ARGV_ARRAY_INIT;
1015
1016         if (is_bare_repository())
1017                 return "denyCurrentBranch = updateInstead needs a worktree";
1018
1019         argv_array_pushf(&env, "GIT_DIR=%s", absolute_path(get_git_dir()));
1020
1021         if (!find_hook(push_to_checkout_hook))
1022                 retval = push_to_deploy(sha1, &env, work_tree);
1023         else
1024                 retval = push_to_checkout(sha1, &env, work_tree);
1025
1026         argv_array_clear(&env);
1027         return retval;
1028 }
1029
1030 static const char *update(struct command *cmd, struct shallow_info *si)
1031 {
1032         const char *name = cmd->ref_name;
1033         struct strbuf namespaced_name_buf = STRBUF_INIT;
1034         static char *namespaced_name;
1035         const char *ret;
1036         struct object_id *old_oid = &cmd->old_oid;
1037         struct object_id *new_oid = &cmd->new_oid;
1038
1039         /* only refs/... are allowed */
1040         if (!starts_with(name, "refs/") || check_refname_format(name + 5, 0)) {
1041                 rp_error("refusing to create funny ref '%s' remotely", name);
1042                 return "funny refname";
1043         }
1044
1045         strbuf_addf(&namespaced_name_buf, "%s%s", get_git_namespace(), name);
1046         free(namespaced_name);
1047         namespaced_name = strbuf_detach(&namespaced_name_buf, NULL);
1048
1049         if (is_ref_checked_out(namespaced_name)) {
1050                 switch (deny_current_branch) {
1051                 case DENY_IGNORE:
1052                         break;
1053                 case DENY_WARN:
1054                         rp_warning("updating the current branch");
1055                         break;
1056                 case DENY_REFUSE:
1057                 case DENY_UNCONFIGURED:
1058                         rp_error("refusing to update checked out branch: %s", name);
1059                         if (deny_current_branch == DENY_UNCONFIGURED)
1060                                 refuse_unconfigured_deny();
1061                         return "branch is currently checked out";
1062                 case DENY_UPDATE_INSTEAD:
1063                         ret = update_worktree(new_oid->hash);
1064                         if (ret)
1065                                 return ret;
1066                         break;
1067                 }
1068         }
1069
1070         if (!is_null_oid(new_oid) && !has_object_file(new_oid)) {
1071                 error("unpack should have generated %s, "
1072                       "but I can't find it!", oid_to_hex(new_oid));
1073                 return "bad pack";
1074         }
1075
1076         if (!is_null_oid(old_oid) && is_null_oid(new_oid)) {
1077                 if (deny_deletes && starts_with(name, "refs/heads/")) {
1078                         rp_error("denying ref deletion for %s", name);
1079                         return "deletion prohibited";
1080                 }
1081
1082                 if (head_name && !strcmp(namespaced_name, head_name)) {
1083                         switch (deny_delete_current) {
1084                         case DENY_IGNORE:
1085                                 break;
1086                         case DENY_WARN:
1087                                 rp_warning("deleting the current branch");
1088                                 break;
1089                         case DENY_REFUSE:
1090                         case DENY_UNCONFIGURED:
1091                         case DENY_UPDATE_INSTEAD:
1092                                 if (deny_delete_current == DENY_UNCONFIGURED)
1093                                         refuse_unconfigured_deny_delete_current();
1094                                 rp_error("refusing to delete the current branch: %s", name);
1095                                 return "deletion of the current branch prohibited";
1096                         default:
1097                                 return "Invalid denyDeleteCurrent setting";
1098                         }
1099                 }
1100         }
1101
1102         if (deny_non_fast_forwards && !is_null_oid(new_oid) &&
1103             !is_null_oid(old_oid) &&
1104             starts_with(name, "refs/heads/")) {
1105                 struct object *old_object, *new_object;
1106                 struct commit *old_commit, *new_commit;
1107
1108                 old_object = parse_object(old_oid);
1109                 new_object = parse_object(new_oid);
1110
1111                 if (!old_object || !new_object ||
1112                     old_object->type != OBJ_COMMIT ||
1113                     new_object->type != OBJ_COMMIT) {
1114                         error("bad sha1 objects for %s", name);
1115                         return "bad ref";
1116                 }
1117                 old_commit = (struct commit *)old_object;
1118                 new_commit = (struct commit *)new_object;
1119                 if (!in_merge_bases(old_commit, new_commit)) {
1120                         rp_error("denying non-fast-forward %s"
1121                                  " (you should pull first)", name);
1122                         return "non-fast-forward";
1123                 }
1124         }
1125         if (run_update_hook(cmd)) {
1126                 rp_error("hook declined to update %s", name);
1127                 return "hook declined";
1128         }
1129
1130         if (is_null_oid(new_oid)) {
1131                 struct strbuf err = STRBUF_INIT;
1132                 if (!parse_object(old_oid)) {
1133                         old_oid = NULL;
1134                         if (ref_exists(name)) {
1135                                 rp_warning("Allowing deletion of corrupt ref.");
1136                         } else {
1137                                 rp_warning("Deleting a non-existent ref.");
1138                                 cmd->did_not_exist = 1;
1139                         }
1140                 }
1141                 if (ref_transaction_delete(transaction,
1142                                            namespaced_name,
1143                                            old_oid,
1144                                            0, "push", &err)) {
1145                         rp_error("%s", err.buf);
1146                         strbuf_release(&err);
1147                         return "failed to delete";
1148                 }
1149                 strbuf_release(&err);
1150                 return NULL; /* good */
1151         }
1152         else {
1153                 struct strbuf err = STRBUF_INIT;
1154                 if (shallow_update && si->shallow_ref[cmd->index] &&
1155                     update_shallow_ref(cmd, si))
1156                         return "shallow error";
1157
1158                 if (ref_transaction_update(transaction,
1159                                            namespaced_name,
1160                                            new_oid, old_oid,
1161                                            0, "push",
1162                                            &err)) {
1163                         rp_error("%s", err.buf);
1164                         strbuf_release(&err);
1165
1166                         return "failed to update ref";
1167                 }
1168                 strbuf_release(&err);
1169
1170                 return NULL; /* good */
1171         }
1172 }
1173
1174 static void run_update_post_hook(struct command *commands)
1175 {
1176         struct command *cmd;
1177         struct child_process proc = CHILD_PROCESS_INIT;
1178         const char *hook;
1179
1180         hook = find_hook("post-update");
1181         if (!hook)
1182                 return;
1183
1184         for (cmd = commands; cmd; cmd = cmd->next) {
1185                 if (cmd->error_string || cmd->did_not_exist)
1186                         continue;
1187                 if (!proc.args.argc)
1188                         argv_array_push(&proc.args, hook);
1189                 argv_array_push(&proc.args, cmd->ref_name);
1190         }
1191         if (!proc.args.argc)
1192                 return;
1193
1194         proc.no_stdin = 1;
1195         proc.stdout_to_stderr = 1;
1196         proc.err = use_sideband ? -1 : 0;
1197
1198         if (!start_command(&proc)) {
1199                 if (use_sideband)
1200                         copy_to_sideband(proc.err, -1, NULL);
1201                 finish_command(&proc);
1202         }
1203 }
1204
1205 static void check_aliased_update(struct command *cmd, struct string_list *list)
1206 {
1207         struct strbuf buf = STRBUF_INIT;
1208         const char *dst_name;
1209         struct string_list_item *item;
1210         struct command *dst_cmd;
1211         int flag;
1212
1213         strbuf_addf(&buf, "%s%s", get_git_namespace(), cmd->ref_name);
1214         dst_name = resolve_ref_unsafe(buf.buf, 0, NULL, &flag);
1215         strbuf_release(&buf);
1216
1217         if (!(flag & REF_ISSYMREF))
1218                 return;
1219
1220         if (!dst_name) {
1221                 rp_error("refusing update to broken symref '%s'", cmd->ref_name);
1222                 cmd->skip_update = 1;
1223                 cmd->error_string = "broken symref";
1224                 return;
1225         }
1226         dst_name = strip_namespace(dst_name);
1227
1228         if ((item = string_list_lookup(list, dst_name)) == NULL)
1229                 return;
1230
1231         cmd->skip_update = 1;
1232
1233         dst_cmd = (struct command *) item->util;
1234
1235         if (!oidcmp(&cmd->old_oid, &dst_cmd->old_oid) &&
1236             !oidcmp(&cmd->new_oid, &dst_cmd->new_oid))
1237                 return;
1238
1239         dst_cmd->skip_update = 1;
1240
1241         rp_error("refusing inconsistent update between symref '%s' (%s..%s) and"
1242                  " its target '%s' (%s..%s)",
1243                  cmd->ref_name,
1244                  find_unique_abbrev(cmd->old_oid.hash, DEFAULT_ABBREV),
1245                  find_unique_abbrev(cmd->new_oid.hash, DEFAULT_ABBREV),
1246                  dst_cmd->ref_name,
1247                  find_unique_abbrev(dst_cmd->old_oid.hash, DEFAULT_ABBREV),
1248                  find_unique_abbrev(dst_cmd->new_oid.hash, DEFAULT_ABBREV));
1249
1250         cmd->error_string = dst_cmd->error_string =
1251                 "inconsistent aliased update";
1252 }
1253
1254 static void check_aliased_updates(struct command *commands)
1255 {
1256         struct command *cmd;
1257         struct string_list ref_list = STRING_LIST_INIT_NODUP;
1258
1259         for (cmd = commands; cmd; cmd = cmd->next) {
1260                 struct string_list_item *item =
1261                         string_list_append(&ref_list, cmd->ref_name);
1262                 item->util = (void *)cmd;
1263         }
1264         string_list_sort(&ref_list);
1265
1266         for (cmd = commands; cmd; cmd = cmd->next) {
1267                 if (!cmd->error_string)
1268                         check_aliased_update(cmd, &ref_list);
1269         }
1270
1271         string_list_clear(&ref_list, 0);
1272 }
1273
1274 static int command_singleton_iterator(void *cb_data, struct object_id *oid)
1275 {
1276         struct command **cmd_list = cb_data;
1277         struct command *cmd = *cmd_list;
1278
1279         if (!cmd || is_null_oid(&cmd->new_oid))
1280                 return -1; /* end of list */
1281         *cmd_list = NULL; /* this returns only one */
1282         oidcpy(oid, &cmd->new_oid);
1283         return 0;
1284 }
1285
1286 static void set_connectivity_errors(struct command *commands,
1287                                     struct shallow_info *si)
1288 {
1289         struct command *cmd;
1290
1291         for (cmd = commands; cmd; cmd = cmd->next) {
1292                 struct command *singleton = cmd;
1293                 struct check_connected_options opt = CHECK_CONNECTED_INIT;
1294
1295                 if (shallow_update && si->shallow_ref[cmd->index])
1296                         /* to be checked in update_shallow_ref() */
1297                         continue;
1298
1299                 opt.env = tmp_objdir_env(tmp_objdir);
1300                 if (!check_connected(command_singleton_iterator, &singleton,
1301                                      &opt))
1302                         continue;
1303
1304                 cmd->error_string = "missing necessary objects";
1305         }
1306 }
1307
1308 struct iterate_data {
1309         struct command *cmds;
1310         struct shallow_info *si;
1311 };
1312
1313 static int iterate_receive_command_list(void *cb_data, struct object_id *oid)
1314 {
1315         struct iterate_data *data = cb_data;
1316         struct command **cmd_list = &data->cmds;
1317         struct command *cmd = *cmd_list;
1318
1319         for (; cmd; cmd = cmd->next) {
1320                 if (shallow_update && data->si->shallow_ref[cmd->index])
1321                         /* to be checked in update_shallow_ref() */
1322                         continue;
1323                 if (!is_null_oid(&cmd->new_oid) && !cmd->skip_update) {
1324                         oidcpy(oid, &cmd->new_oid);
1325                         *cmd_list = cmd->next;
1326                         return 0;
1327                 }
1328         }
1329         *cmd_list = NULL;
1330         return -1; /* end of list */
1331 }
1332
1333 static void reject_updates_to_hidden(struct command *commands)
1334 {
1335         struct strbuf refname_full = STRBUF_INIT;
1336         size_t prefix_len;
1337         struct command *cmd;
1338
1339         strbuf_addstr(&refname_full, get_git_namespace());
1340         prefix_len = refname_full.len;
1341
1342         for (cmd = commands; cmd; cmd = cmd->next) {
1343                 if (cmd->error_string)
1344                         continue;
1345
1346                 strbuf_setlen(&refname_full, prefix_len);
1347                 strbuf_addstr(&refname_full, cmd->ref_name);
1348
1349                 if (!ref_is_hidden(cmd->ref_name, refname_full.buf))
1350                         continue;
1351                 if (is_null_oid(&cmd->new_oid))
1352                         cmd->error_string = "deny deleting a hidden ref";
1353                 else
1354                         cmd->error_string = "deny updating a hidden ref";
1355         }
1356
1357         strbuf_release(&refname_full);
1358 }
1359
1360 static int should_process_cmd(struct command *cmd)
1361 {
1362         return !cmd->error_string && !cmd->skip_update;
1363 }
1364
1365 static void warn_if_skipped_connectivity_check(struct command *commands,
1366                                                struct shallow_info *si)
1367 {
1368         struct command *cmd;
1369         int checked_connectivity = 1;
1370
1371         for (cmd = commands; cmd; cmd = cmd->next) {
1372                 if (should_process_cmd(cmd) && si->shallow_ref[cmd->index]) {
1373                         error("BUG: connectivity check has not been run on ref %s",
1374                               cmd->ref_name);
1375                         checked_connectivity = 0;
1376                 }
1377         }
1378         if (!checked_connectivity)
1379                 die("BUG: connectivity check skipped???");
1380 }
1381
1382 static void execute_commands_non_atomic(struct command *commands,
1383                                         struct shallow_info *si)
1384 {
1385         struct command *cmd;
1386         struct strbuf err = STRBUF_INIT;
1387
1388         for (cmd = commands; cmd; cmd = cmd->next) {
1389                 if (!should_process_cmd(cmd))
1390                         continue;
1391
1392                 transaction = ref_transaction_begin(&err);
1393                 if (!transaction) {
1394                         rp_error("%s", err.buf);
1395                         strbuf_reset(&err);
1396                         cmd->error_string = "transaction failed to start";
1397                         continue;
1398                 }
1399
1400                 cmd->error_string = update(cmd, si);
1401
1402                 if (!cmd->error_string
1403                     && ref_transaction_commit(transaction, &err)) {
1404                         rp_error("%s", err.buf);
1405                         strbuf_reset(&err);
1406                         cmd->error_string = "failed to update ref";
1407                 }
1408                 ref_transaction_free(transaction);
1409         }
1410         strbuf_release(&err);
1411 }
1412
1413 static void execute_commands_atomic(struct command *commands,
1414                                         struct shallow_info *si)
1415 {
1416         struct command *cmd;
1417         struct strbuf err = STRBUF_INIT;
1418         const char *reported_error = "atomic push failure";
1419
1420         transaction = ref_transaction_begin(&err);
1421         if (!transaction) {
1422                 rp_error("%s", err.buf);
1423                 strbuf_reset(&err);
1424                 reported_error = "transaction failed to start";
1425                 goto failure;
1426         }
1427
1428         for (cmd = commands; cmd; cmd = cmd->next) {
1429                 if (!should_process_cmd(cmd))
1430                         continue;
1431
1432                 cmd->error_string = update(cmd, si);
1433
1434                 if (cmd->error_string)
1435                         goto failure;
1436         }
1437
1438         if (ref_transaction_commit(transaction, &err)) {
1439                 rp_error("%s", err.buf);
1440                 reported_error = "atomic transaction failed";
1441                 goto failure;
1442         }
1443         goto cleanup;
1444
1445 failure:
1446         for (cmd = commands; cmd; cmd = cmd->next)
1447                 if (!cmd->error_string)
1448                         cmd->error_string = reported_error;
1449
1450 cleanup:
1451         ref_transaction_free(transaction);
1452         strbuf_release(&err);
1453 }
1454
1455 static void execute_commands(struct command *commands,
1456                              const char *unpacker_error,
1457                              struct shallow_info *si,
1458                              const struct string_list *push_options)
1459 {
1460         struct check_connected_options opt = CHECK_CONNECTED_INIT;
1461         struct command *cmd;
1462         struct iterate_data data;
1463         struct async muxer;
1464         int err_fd = 0;
1465
1466         if (unpacker_error) {
1467                 for (cmd = commands; cmd; cmd = cmd->next)
1468                         cmd->error_string = "unpacker error";
1469                 return;
1470         }
1471
1472         if (use_sideband) {
1473                 memset(&muxer, 0, sizeof(muxer));
1474                 muxer.proc = copy_to_sideband;
1475                 muxer.in = -1;
1476                 if (!start_async(&muxer))
1477                         err_fd = muxer.in;
1478                 /* ...else, continue without relaying sideband */
1479         }
1480
1481         data.cmds = commands;
1482         data.si = si;
1483         opt.err_fd = err_fd;
1484         opt.progress = err_fd && !quiet;
1485         opt.env = tmp_objdir_env(tmp_objdir);
1486         if (check_connected(iterate_receive_command_list, &data, &opt))
1487                 set_connectivity_errors(commands, si);
1488
1489         if (use_sideband)
1490                 finish_async(&muxer);
1491
1492         reject_updates_to_hidden(commands);
1493
1494         if (run_receive_hook(commands, "pre-receive", 0, push_options)) {
1495                 for (cmd = commands; cmd; cmd = cmd->next) {
1496                         if (!cmd->error_string)
1497                                 cmd->error_string = "pre-receive hook declined";
1498                 }
1499                 return;
1500         }
1501
1502         /*
1503          * Now we'll start writing out refs, which means the objects need
1504          * to be in their final positions so that other processes can see them.
1505          */
1506         if (tmp_objdir_migrate(tmp_objdir) < 0) {
1507                 for (cmd = commands; cmd; cmd = cmd->next) {
1508                         if (!cmd->error_string)
1509                                 cmd->error_string = "unable to migrate objects to permanent storage";
1510                 }
1511                 return;
1512         }
1513         tmp_objdir = NULL;
1514
1515         check_aliased_updates(commands);
1516
1517         free(head_name_to_free);
1518         head_name = head_name_to_free = resolve_refdup("HEAD", 0, NULL, NULL);
1519
1520         if (use_atomic)
1521                 execute_commands_atomic(commands, si);
1522         else
1523                 execute_commands_non_atomic(commands, si);
1524
1525         if (shallow_update)
1526                 warn_if_skipped_connectivity_check(commands, si);
1527 }
1528
1529 static struct command **queue_command(struct command **tail,
1530                                       const char *line,
1531                                       int linelen)
1532 {
1533         struct object_id old_oid, new_oid;
1534         struct command *cmd;
1535         const char *refname;
1536         int reflen;
1537         const char *p;
1538
1539         if (parse_oid_hex(line, &old_oid, &p) ||
1540             *p++ != ' ' ||
1541             parse_oid_hex(p, &new_oid, &p) ||
1542             *p++ != ' ')
1543                 die("protocol error: expected old/new/ref, got '%s'", line);
1544
1545         refname = p;
1546         reflen = linelen - (p - line);
1547         FLEX_ALLOC_MEM(cmd, ref_name, refname, reflen);
1548         oidcpy(&cmd->old_oid, &old_oid);
1549         oidcpy(&cmd->new_oid, &new_oid);
1550         *tail = cmd;
1551         return &cmd->next;
1552 }
1553
1554 static void queue_commands_from_cert(struct command **tail,
1555                                      struct strbuf *push_cert)
1556 {
1557         const char *boc, *eoc;
1558
1559         if (*tail)
1560                 die("protocol error: got both push certificate and unsigned commands");
1561
1562         boc = strstr(push_cert->buf, "\n\n");
1563         if (!boc)
1564                 die("malformed push certificate %.*s", 100, push_cert->buf);
1565         else
1566                 boc += 2;
1567         eoc = push_cert->buf + parse_signature(push_cert->buf, push_cert->len);
1568
1569         while (boc < eoc) {
1570                 const char *eol = memchr(boc, '\n', eoc - boc);
1571                 tail = queue_command(tail, boc, eol ? eol - boc : eoc - boc);
1572                 boc = eol ? eol + 1 : eoc;
1573         }
1574 }
1575
1576 static struct command *read_head_info(struct oid_array *shallow)
1577 {
1578         struct command *commands = NULL;
1579         struct command **p = &commands;
1580         for (;;) {
1581                 char *line;
1582                 int len, linelen;
1583
1584                 line = packet_read_line(0, &len);
1585                 if (!line)
1586                         break;
1587
1588                 if (len > 8 && starts_with(line, "shallow ")) {
1589                         struct object_id oid;
1590                         if (get_oid_hex(line + 8, &oid))
1591                                 die("protocol error: expected shallow sha, got '%s'",
1592                                     line + 8);
1593                         oid_array_append(shallow, &oid);
1594                         continue;
1595                 }
1596
1597                 linelen = strlen(line);
1598                 if (linelen < len) {
1599                         const char *feature_list = line + linelen + 1;
1600                         if (parse_feature_request(feature_list, "report-status"))
1601                                 report_status = 1;
1602                         if (parse_feature_request(feature_list, "side-band-64k"))
1603                                 use_sideband = LARGE_PACKET_MAX;
1604                         if (parse_feature_request(feature_list, "quiet"))
1605                                 quiet = 1;
1606                         if (advertise_atomic_push
1607                             && parse_feature_request(feature_list, "atomic"))
1608                                 use_atomic = 1;
1609                         if (advertise_push_options
1610                             && parse_feature_request(feature_list, "push-options"))
1611                                 use_push_options = 1;
1612                 }
1613
1614                 if (!strcmp(line, "push-cert")) {
1615                         int true_flush = 0;
1616                         char certbuf[1024];
1617
1618                         for (;;) {
1619                                 len = packet_read(0, NULL, NULL,
1620                                                   certbuf, sizeof(certbuf), 0);
1621                                 if (!len) {
1622                                         true_flush = 1;
1623                                         break;
1624                                 }
1625                                 if (!strcmp(certbuf, "push-cert-end\n"))
1626                                         break; /* end of cert */
1627                                 strbuf_addstr(&push_cert, certbuf);
1628                         }
1629
1630                         if (true_flush)
1631                                 break;
1632                         continue;
1633                 }
1634
1635                 p = queue_command(p, line, linelen);
1636         }
1637
1638         if (push_cert.len)
1639                 queue_commands_from_cert(p, &push_cert);
1640
1641         return commands;
1642 }
1643
1644 static void read_push_options(struct string_list *options)
1645 {
1646         while (1) {
1647                 char *line;
1648                 int len;
1649
1650                 line = packet_read_line(0, &len);
1651
1652                 if (!line)
1653                         break;
1654
1655                 string_list_append(options, line);
1656         }
1657 }
1658
1659 static const char *parse_pack_header(struct pack_header *hdr)
1660 {
1661         switch (read_pack_header(0, hdr)) {
1662         case PH_ERROR_EOF:
1663                 return "eof before pack header was fully read";
1664
1665         case PH_ERROR_PACK_SIGNATURE:
1666                 return "protocol error (pack signature mismatch detected)";
1667
1668         case PH_ERROR_PROTOCOL:
1669                 return "protocol error (pack version unsupported)";
1670
1671         default:
1672                 return "unknown error in parse_pack_header";
1673
1674         case 0:
1675                 return NULL;
1676         }
1677 }
1678
1679 static const char *pack_lockfile;
1680
1681 static void push_header_arg(struct argv_array *args, struct pack_header *hdr)
1682 {
1683         argv_array_pushf(args, "--pack_header=%"PRIu32",%"PRIu32,
1684                         ntohl(hdr->hdr_version), ntohl(hdr->hdr_entries));
1685 }
1686
1687 static const char *unpack(int err_fd, struct shallow_info *si)
1688 {
1689         struct pack_header hdr;
1690         const char *hdr_err;
1691         int status;
1692         struct child_process child = CHILD_PROCESS_INIT;
1693         int fsck_objects = (receive_fsck_objects >= 0
1694                             ? receive_fsck_objects
1695                             : transfer_fsck_objects >= 0
1696                             ? transfer_fsck_objects
1697                             : 0);
1698
1699         hdr_err = parse_pack_header(&hdr);
1700         if (hdr_err) {
1701                 if (err_fd > 0)
1702                         close(err_fd);
1703                 return hdr_err;
1704         }
1705
1706         if (si->nr_ours || si->nr_theirs) {
1707                 alt_shallow_file = setup_temporary_shallow(si->shallow);
1708                 argv_array_push(&child.args, "--shallow-file");
1709                 argv_array_push(&child.args, alt_shallow_file);
1710         }
1711
1712         tmp_objdir = tmp_objdir_create();
1713         if (!tmp_objdir) {
1714                 if (err_fd > 0)
1715                         close(err_fd);
1716                 return "unable to create temporary object directory";
1717         }
1718         child.env = tmp_objdir_env(tmp_objdir);
1719
1720         /*
1721          * Normally we just pass the tmp_objdir environment to the child
1722          * processes that do the heavy lifting, but we may need to see these
1723          * objects ourselves to set up shallow information.
1724          */
1725         tmp_objdir_add_as_alternate(tmp_objdir);
1726
1727         if (ntohl(hdr.hdr_entries) < unpack_limit) {
1728                 argv_array_push(&child.args, "unpack-objects");
1729                 push_header_arg(&child.args, &hdr);
1730                 if (quiet)
1731                         argv_array_push(&child.args, "-q");
1732                 if (fsck_objects)
1733                         argv_array_pushf(&child.args, "--strict%s",
1734                                 fsck_msg_types.buf);
1735                 if (max_input_size)
1736                         argv_array_pushf(&child.args, "--max-input-size=%"PRIuMAX,
1737                                 (uintmax_t)max_input_size);
1738                 child.no_stdout = 1;
1739                 child.err = err_fd;
1740                 child.git_cmd = 1;
1741                 status = run_command(&child);
1742                 if (status)
1743                         return "unpack-objects abnormal exit";
1744         } else {
1745                 char hostname[HOST_NAME_MAX + 1];
1746
1747                 argv_array_pushl(&child.args, "index-pack", "--stdin", NULL);
1748                 push_header_arg(&child.args, &hdr);
1749
1750                 if (xgethostname(hostname, sizeof(hostname)))
1751                         xsnprintf(hostname, sizeof(hostname), "localhost");
1752                 argv_array_pushf(&child.args,
1753                                  "--keep=receive-pack %"PRIuMAX" on %s",
1754                                  (uintmax_t)getpid(),
1755                                  hostname);
1756
1757                 if (!quiet && err_fd)
1758                         argv_array_push(&child.args, "--show-resolving-progress");
1759                 if (use_sideband)
1760                         argv_array_push(&child.args, "--report-end-of-input");
1761                 if (fsck_objects)
1762                         argv_array_pushf(&child.args, "--strict%s",
1763                                 fsck_msg_types.buf);
1764                 if (!reject_thin)
1765                         argv_array_push(&child.args, "--fix-thin");
1766                 if (max_input_size)
1767                         argv_array_pushf(&child.args, "--max-input-size=%"PRIuMAX,
1768                                 (uintmax_t)max_input_size);
1769                 child.out = -1;
1770                 child.err = err_fd;
1771                 child.git_cmd = 1;
1772                 status = start_command(&child);
1773                 if (status)
1774                         return "index-pack fork failed";
1775                 pack_lockfile = index_pack_lockfile(child.out);
1776                 close(child.out);
1777                 status = finish_command(&child);
1778                 if (status)
1779                         return "index-pack abnormal exit";
1780                 reprepare_packed_git();
1781         }
1782         return NULL;
1783 }
1784
1785 static const char *unpack_with_sideband(struct shallow_info *si)
1786 {
1787         struct async muxer;
1788         const char *ret;
1789
1790         if (!use_sideband)
1791                 return unpack(0, si);
1792
1793         use_keepalive = KEEPALIVE_AFTER_NUL;
1794         memset(&muxer, 0, sizeof(muxer));
1795         muxer.proc = copy_to_sideband;
1796         muxer.in = -1;
1797         if (start_async(&muxer))
1798                 return NULL;
1799
1800         ret = unpack(muxer.in, si);
1801
1802         finish_async(&muxer);
1803         return ret;
1804 }
1805
1806 static void prepare_shallow_update(struct command *commands,
1807                                    struct shallow_info *si)
1808 {
1809         int i, j, k, bitmap_size = DIV_ROUND_UP(si->ref->nr, 32);
1810
1811         ALLOC_ARRAY(si->used_shallow, si->shallow->nr);
1812         assign_shallow_commits_to_refs(si, si->used_shallow, NULL);
1813
1814         si->need_reachability_test =
1815                 xcalloc(si->shallow->nr, sizeof(*si->need_reachability_test));
1816         si->reachable =
1817                 xcalloc(si->shallow->nr, sizeof(*si->reachable));
1818         si->shallow_ref = xcalloc(si->ref->nr, sizeof(*si->shallow_ref));
1819
1820         for (i = 0; i < si->nr_ours; i++)
1821                 si->need_reachability_test[si->ours[i]] = 1;
1822
1823         for (i = 0; i < si->shallow->nr; i++) {
1824                 if (!si->used_shallow[i])
1825                         continue;
1826                 for (j = 0; j < bitmap_size; j++) {
1827                         if (!si->used_shallow[i][j])
1828                                 continue;
1829                         si->need_reachability_test[i]++;
1830                         for (k = 0; k < 32; k++)
1831                                 if (si->used_shallow[i][j] & (1U << k))
1832                                         si->shallow_ref[j * 32 + k]++;
1833                 }
1834
1835                 /*
1836                  * true for those associated with some refs and belong
1837                  * in "ours" list aka "step 7 not done yet"
1838                  */
1839                 si->need_reachability_test[i] =
1840                         si->need_reachability_test[i] > 1;
1841         }
1842
1843         /*
1844          * keep hooks happy by forcing a temporary shallow file via
1845          * env variable because we can't add --shallow-file to every
1846          * command. check_everything_connected() will be done with
1847          * true .git/shallow though.
1848          */
1849         setenv(GIT_SHALLOW_FILE_ENVIRONMENT, alt_shallow_file, 1);
1850 }
1851
1852 static void update_shallow_info(struct command *commands,
1853                                 struct shallow_info *si,
1854                                 struct oid_array *ref)
1855 {
1856         struct command *cmd;
1857         int *ref_status;
1858         remove_nonexistent_theirs_shallow(si);
1859         if (!si->nr_ours && !si->nr_theirs) {
1860                 shallow_update = 0;
1861                 return;
1862         }
1863
1864         for (cmd = commands; cmd; cmd = cmd->next) {
1865                 if (is_null_oid(&cmd->new_oid))
1866                         continue;
1867                 oid_array_append(ref, &cmd->new_oid);
1868                 cmd->index = ref->nr - 1;
1869         }
1870         si->ref = ref;
1871
1872         if (shallow_update) {
1873                 prepare_shallow_update(commands, si);
1874                 return;
1875         }
1876
1877         ALLOC_ARRAY(ref_status, ref->nr);
1878         assign_shallow_commits_to_refs(si, NULL, ref_status);
1879         for (cmd = commands; cmd; cmd = cmd->next) {
1880                 if (is_null_oid(&cmd->new_oid))
1881                         continue;
1882                 if (ref_status[cmd->index]) {
1883                         cmd->error_string = "shallow update not allowed";
1884                         cmd->skip_update = 1;
1885                 }
1886         }
1887         free(ref_status);
1888 }
1889
1890 static void report(struct command *commands, const char *unpack_status)
1891 {
1892         struct command *cmd;
1893         struct strbuf buf = STRBUF_INIT;
1894
1895         packet_buf_write(&buf, "unpack %s\n",
1896                          unpack_status ? unpack_status : "ok");
1897         for (cmd = commands; cmd; cmd = cmd->next) {
1898                 if (!cmd->error_string)
1899                         packet_buf_write(&buf, "ok %s\n",
1900                                          cmd->ref_name);
1901                 else
1902                         packet_buf_write(&buf, "ng %s %s\n",
1903                                          cmd->ref_name, cmd->error_string);
1904         }
1905         packet_buf_flush(&buf);
1906
1907         if (use_sideband)
1908                 send_sideband(1, 1, buf.buf, buf.len, use_sideband);
1909         else
1910                 write_or_die(1, buf.buf, buf.len);
1911         strbuf_release(&buf);
1912 }
1913
1914 static int delete_only(struct command *commands)
1915 {
1916         struct command *cmd;
1917         for (cmd = commands; cmd; cmd = cmd->next) {
1918                 if (!is_null_oid(&cmd->new_oid))
1919                         return 0;
1920         }
1921         return 1;
1922 }
1923
1924 int cmd_receive_pack(int argc, const char **argv, const char *prefix)
1925 {
1926         int advertise_refs = 0;
1927         struct command *commands;
1928         struct oid_array shallow = OID_ARRAY_INIT;
1929         struct oid_array ref = OID_ARRAY_INIT;
1930         struct shallow_info si;
1931
1932         struct option options[] = {
1933                 OPT__QUIET(&quiet, N_("quiet")),
1934                 OPT_HIDDEN_BOOL(0, "stateless-rpc", &stateless_rpc, NULL),
1935                 OPT_HIDDEN_BOOL(0, "advertise-refs", &advertise_refs, NULL),
1936                 OPT_HIDDEN_BOOL(0, "reject-thin-pack-for-testing", &reject_thin, NULL),
1937                 OPT_END()
1938         };
1939
1940         packet_trace_identity("receive-pack");
1941
1942         argc = parse_options(argc, argv, prefix, options, receive_pack_usage, 0);
1943
1944         if (argc > 1)
1945                 usage_msg_opt(_("Too many arguments."), receive_pack_usage, options);
1946         if (argc == 0)
1947                 usage_msg_opt(_("You must specify a directory."), receive_pack_usage, options);
1948
1949         service_dir = argv[0];
1950
1951         setup_path();
1952
1953         if (!enter_repo(service_dir, 0))
1954                 die("'%s' does not appear to be a git repository", service_dir);
1955
1956         git_config(receive_pack_config, NULL);
1957         if (cert_nonce_seed)
1958                 push_cert_nonce = prepare_push_cert_nonce(service_dir, time(NULL));
1959
1960         if (0 <= transfer_unpack_limit)
1961                 unpack_limit = transfer_unpack_limit;
1962         else if (0 <= receive_unpack_limit)
1963                 unpack_limit = receive_unpack_limit;
1964
1965         switch (determine_protocol_version_server()) {
1966         case protocol_v1:
1967                 /*
1968                  * v1 is just the original protocol with a version string,
1969                  * so just fall through after writing the version string.
1970                  */
1971                 if (advertise_refs || !stateless_rpc)
1972                         packet_write_fmt(1, "version 1\n");
1973
1974                 /* fallthrough */
1975         case protocol_v0:
1976                 break;
1977         case protocol_unknown_version:
1978                 BUG("unknown protocol version");
1979         }
1980
1981         if (advertise_refs || !stateless_rpc) {
1982                 write_head_info();
1983         }
1984         if (advertise_refs)
1985                 return 0;
1986
1987         if ((commands = read_head_info(&shallow)) != NULL) {
1988                 const char *unpack_status = NULL;
1989                 struct string_list push_options = STRING_LIST_INIT_DUP;
1990
1991                 if (use_push_options)
1992                         read_push_options(&push_options);
1993                 if (!check_cert_push_options(&push_options)) {
1994                         struct command *cmd;
1995                         for (cmd = commands; cmd; cmd = cmd->next)
1996                                 cmd->error_string = "inconsistent push options";
1997                 }
1998
1999                 prepare_shallow_info(&si, &shallow);
2000                 if (!si.nr_ours && !si.nr_theirs)
2001                         shallow_update = 0;
2002                 if (!delete_only(commands)) {
2003                         unpack_status = unpack_with_sideband(&si);
2004                         update_shallow_info(commands, &si, &ref);
2005                 }
2006                 use_keepalive = KEEPALIVE_ALWAYS;
2007                 execute_commands(commands, unpack_status, &si,
2008                                  &push_options);
2009                 if (pack_lockfile)
2010                         unlink_or_warn(pack_lockfile);
2011                 if (report_status)
2012                         report(commands, unpack_status);
2013                 run_receive_hook(commands, "post-receive", 1,
2014                                  &push_options);
2015                 run_update_post_hook(commands);
2016                 string_list_clear(&push_options, 0);
2017                 if (auto_gc) {
2018                         const char *argv_gc_auto[] = {
2019                                 "gc", "--auto", "--quiet", NULL,
2020                         };
2021                         struct child_process proc = CHILD_PROCESS_INIT;
2022
2023                         proc.no_stdin = 1;
2024                         proc.stdout_to_stderr = 1;
2025                         proc.err = use_sideband ? -1 : 0;
2026                         proc.git_cmd = 1;
2027                         proc.argv = argv_gc_auto;
2028
2029                         close_all_packs();
2030                         if (!start_command(&proc)) {
2031                                 if (use_sideband)
2032                                         copy_to_sideband(proc.err, -1, NULL);
2033                                 finish_command(&proc);
2034                         }
2035                 }
2036                 if (auto_update_server_info)
2037                         update_server_info(0);
2038                 clear_shallow_info(&si);
2039         }
2040         if (use_sideband)
2041                 packet_flush(1);
2042         oid_array_clear(&shallow);
2043         oid_array_clear(&ref);
2044         free((void *)push_cert_nonce);
2045         return 0;
2046 }