t1700-split-index: date back files to avoid racy situations
[git] / http-walker.c
1 #include "cache.h"
2 #include "repository.h"
3 #include "commit.h"
4 #include "walker.h"
5 #include "http.h"
6 #include "list.h"
7 #include "transport.h"
8 #include "packfile.h"
9 #include "object-store.h"
10
11 struct alt_base {
12         char *base;
13         int got_indices;
14         struct packed_git *packs;
15         struct alt_base *next;
16 };
17
18 enum object_request_state {
19         WAITING,
20         ABORTED,
21         ACTIVE,
22         COMPLETE
23 };
24
25 struct object_request {
26         struct walker *walker;
27         struct object_id oid;
28         struct alt_base *repo;
29         enum object_request_state state;
30         struct http_object_request *req;
31         struct list_head node;
32 };
33
34 struct alternates_request {
35         struct walker *walker;
36         const char *base;
37         struct strbuf *url;
38         struct strbuf *buffer;
39         struct active_request_slot *slot;
40         int http_specific;
41 };
42
43 struct walker_data {
44         const char *url;
45         int got_alternates;
46         struct alt_base *alt;
47 };
48
49 static LIST_HEAD(object_queue_head);
50
51 static void fetch_alternates(struct walker *walker, const char *base);
52
53 static void process_object_response(void *callback_data);
54
55 static void start_object_request(struct walker *walker,
56                                  struct object_request *obj_req)
57 {
58         struct active_request_slot *slot;
59         struct http_object_request *req;
60
61         req = new_http_object_request(obj_req->repo->base, obj_req->oid.hash);
62         if (req == NULL) {
63                 obj_req->state = ABORTED;
64                 return;
65         }
66         obj_req->req = req;
67
68         slot = req->slot;
69         slot->callback_func = process_object_response;
70         slot->callback_data = obj_req;
71
72         /* Try to get the request started, abort the request on error */
73         obj_req->state = ACTIVE;
74         if (!start_active_slot(slot)) {
75                 obj_req->state = ABORTED;
76                 release_http_object_request(req);
77                 return;
78         }
79 }
80
81 static void finish_object_request(struct object_request *obj_req)
82 {
83         if (finish_http_object_request(obj_req->req))
84                 return;
85
86         if (obj_req->req->rename == 0)
87                 walker_say(obj_req->walker, "got %s\n", oid_to_hex(&obj_req->oid));
88 }
89
90 static void process_object_response(void *callback_data)
91 {
92         struct object_request *obj_req =
93                 (struct object_request *)callback_data;
94         struct walker *walker = obj_req->walker;
95         struct walker_data *data = walker->data;
96         struct alt_base *alt = data->alt;
97
98         process_http_object_request(obj_req->req);
99         obj_req->state = COMPLETE;
100
101         /* Use alternates if necessary */
102         if (missing_target(obj_req->req)) {
103                 fetch_alternates(walker, alt->base);
104                 if (obj_req->repo->next != NULL) {
105                         obj_req->repo =
106                                 obj_req->repo->next;
107                         release_http_object_request(obj_req->req);
108                         start_object_request(walker, obj_req);
109                         return;
110                 }
111         }
112
113         finish_object_request(obj_req);
114 }
115
116 static void release_object_request(struct object_request *obj_req)
117 {
118         if (obj_req->req !=NULL && obj_req->req->localfile != -1)
119                 error("fd leakage in release: %d", obj_req->req->localfile);
120
121         list_del(&obj_req->node);
122         free(obj_req);
123 }
124
125 #ifdef USE_CURL_MULTI
126 static int fill_active_slot(struct walker *walker)
127 {
128         struct object_request *obj_req;
129         struct list_head *pos, *tmp, *head = &object_queue_head;
130
131         list_for_each_safe(pos, tmp, head) {
132                 obj_req = list_entry(pos, struct object_request, node);
133                 if (obj_req->state == WAITING) {
134                         if (has_sha1_file(obj_req->oid.hash))
135                                 obj_req->state = COMPLETE;
136                         else {
137                                 start_object_request(walker, obj_req);
138                                 return 1;
139                         }
140                 }
141         }
142         return 0;
143 }
144 #endif
145
146 static void prefetch(struct walker *walker, unsigned char *sha1)
147 {
148         struct object_request *newreq;
149         struct walker_data *data = walker->data;
150
151         newreq = xmalloc(sizeof(*newreq));
152         newreq->walker = walker;
153         hashcpy(newreq->oid.hash, sha1);
154         newreq->repo = data->alt;
155         newreq->state = WAITING;
156         newreq->req = NULL;
157
158         http_is_verbose = walker->get_verbosely;
159         list_add_tail(&newreq->node, &object_queue_head);
160
161 #ifdef USE_CURL_MULTI
162         fill_active_slots();
163         step_active_slots();
164 #endif
165 }
166
167 static int is_alternate_allowed(const char *url)
168 {
169         const char *protocols[] = {
170                 "http", "https", "ftp", "ftps"
171         };
172         int i;
173
174         if (http_follow_config != HTTP_FOLLOW_ALWAYS) {
175                 warning("alternate disabled by http.followRedirects: %s", url);
176                 return 0;
177         }
178
179         for (i = 0; i < ARRAY_SIZE(protocols); i++) {
180                 const char *end;
181                 if (skip_prefix(url, protocols[i], &end) &&
182                     starts_with(end, "://"))
183                         break;
184         }
185
186         if (i >= ARRAY_SIZE(protocols)) {
187                 warning("ignoring alternate with unknown protocol: %s", url);
188                 return 0;
189         }
190         if (!is_transport_allowed(protocols[i], 0)) {
191                 warning("ignoring alternate with restricted protocol: %s", url);
192                 return 0;
193         }
194
195         return 1;
196 }
197
198 static void process_alternates_response(void *callback_data)
199 {
200         struct alternates_request *alt_req =
201                 (struct alternates_request *)callback_data;
202         struct walker *walker = alt_req->walker;
203         struct walker_data *cdata = walker->data;
204         struct active_request_slot *slot = alt_req->slot;
205         struct alt_base *tail = cdata->alt;
206         const char *base = alt_req->base;
207         const char null_byte = '\0';
208         char *data;
209         int i = 0;
210
211         if (alt_req->http_specific) {
212                 if (slot->curl_result != CURLE_OK ||
213                     !alt_req->buffer->len) {
214
215                         /* Try reusing the slot to get non-http alternates */
216                         alt_req->http_specific = 0;
217                         strbuf_reset(alt_req->url);
218                         strbuf_addf(alt_req->url, "%s/objects/info/alternates",
219                                     base);
220                         curl_easy_setopt(slot->curl, CURLOPT_URL,
221                                          alt_req->url->buf);
222                         active_requests++;
223                         slot->in_use = 1;
224                         if (slot->finished != NULL)
225                                 (*slot->finished) = 0;
226                         if (!start_active_slot(slot)) {
227                                 cdata->got_alternates = -1;
228                                 slot->in_use = 0;
229                                 if (slot->finished != NULL)
230                                         (*slot->finished) = 1;
231                         }
232                         return;
233                 }
234         } else if (slot->curl_result != CURLE_OK) {
235                 if (!missing_target(slot)) {
236                         cdata->got_alternates = -1;
237                         return;
238                 }
239         }
240
241         fwrite_buffer((char *)&null_byte, 1, 1, alt_req->buffer);
242         alt_req->buffer->len--;
243         data = alt_req->buffer->buf;
244
245         while (i < alt_req->buffer->len) {
246                 int posn = i;
247                 while (posn < alt_req->buffer->len && data[posn] != '\n')
248                         posn++;
249                 if (data[posn] == '\n') {
250                         int okay = 0;
251                         int serverlen = 0;
252                         struct alt_base *newalt;
253                         if (data[i] == '/') {
254                                 /*
255                                  * This counts
256                                  * http://git.host/pub/scm/linux.git/
257                                  * -----------here^
258                                  * so memcpy(dst, base, serverlen) will
259                                  * copy up to "...git.host".
260                                  */
261                                 const char *colon_ss = strstr(base,"://");
262                                 if (colon_ss) {
263                                         serverlen = (strchr(colon_ss + 3, '/')
264                                                      - base);
265                                         okay = 1;
266                                 }
267                         } else if (!memcmp(data + i, "../", 3)) {
268                                 /*
269                                  * Relative URL; chop the corresponding
270                                  * number of subpath from base (and ../
271                                  * from data), and concatenate the result.
272                                  *
273                                  * The code first drops ../ from data, and
274                                  * then drops one ../ from data and one path
275                                  * from base.  IOW, one extra ../ is dropped
276                                  * from data than path is dropped from base.
277                                  *
278                                  * This is not wrong.  The alternate in
279                                  *     http://git.host/pub/scm/linux.git/
280                                  * to borrow from
281                                  *     http://git.host/pub/scm/linus.git/
282                                  * is ../../linus.git/objects/.  You need
283                                  * two ../../ to borrow from your direct
284                                  * neighbour.
285                                  */
286                                 i += 3;
287                                 serverlen = strlen(base);
288                                 while (i + 2 < posn &&
289                                        !memcmp(data + i, "../", 3)) {
290                                         do {
291                                                 serverlen--;
292                                         } while (serverlen &&
293                                                  base[serverlen - 1] != '/');
294                                         i += 3;
295                                 }
296                                 /* If the server got removed, give up. */
297                                 okay = strchr(base, ':') - base + 3 <
298                                        serverlen;
299                         } else if (alt_req->http_specific) {
300                                 char *colon = strchr(data + i, ':');
301                                 char *slash = strchr(data + i, '/');
302                                 if (colon && slash && colon < data + posn &&
303                                     slash < data + posn && colon < slash) {
304                                         okay = 1;
305                                 }
306                         }
307                         if (okay) {
308                                 struct strbuf target = STRBUF_INIT;
309                                 strbuf_add(&target, base, serverlen);
310                                 strbuf_add(&target, data + i, posn - i);
311                                 if (!strbuf_strip_suffix(&target, "objects")) {
312                                         warning("ignoring alternate that does"
313                                                 " not end in 'objects': %s",
314                                                 target.buf);
315                                         strbuf_release(&target);
316                                 } else if (is_alternate_allowed(target.buf)) {
317                                         warning("adding alternate object store: %s",
318                                                 target.buf);
319                                         newalt = xmalloc(sizeof(*newalt));
320                                         newalt->next = NULL;
321                                         newalt->base = strbuf_detach(&target, NULL);
322                                         newalt->got_indices = 0;
323                                         newalt->packs = NULL;
324
325                                         while (tail->next != NULL)
326                                                 tail = tail->next;
327                                         tail->next = newalt;
328                                 } else {
329                                         strbuf_release(&target);
330                                 }
331                         }
332                 }
333                 i = posn + 1;
334         }
335
336         cdata->got_alternates = 1;
337 }
338
339 static void fetch_alternates(struct walker *walker, const char *base)
340 {
341         struct strbuf buffer = STRBUF_INIT;
342         struct strbuf url = STRBUF_INIT;
343         struct active_request_slot *slot;
344         struct alternates_request alt_req;
345         struct walker_data *cdata = walker->data;
346
347         /*
348          * If another request has already started fetching alternates,
349          * wait for them to arrive and return to processing this request's
350          * curl message
351          */
352 #ifdef USE_CURL_MULTI
353         while (cdata->got_alternates == 0) {
354                 step_active_slots();
355         }
356 #endif
357
358         /* Nothing to do if they've already been fetched */
359         if (cdata->got_alternates == 1)
360                 return;
361
362         /* Start the fetch */
363         cdata->got_alternates = 0;
364
365         if (walker->get_verbosely)
366                 fprintf(stderr, "Getting alternates list for %s\n", base);
367
368         strbuf_addf(&url, "%s/objects/info/http-alternates", base);
369
370         /*
371          * Use a callback to process the result, since another request
372          * may fail and need to have alternates loaded before continuing
373          */
374         slot = get_active_slot();
375         slot->callback_func = process_alternates_response;
376         alt_req.walker = walker;
377         slot->callback_data = &alt_req;
378
379         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
380         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
381         curl_easy_setopt(slot->curl, CURLOPT_URL, url.buf);
382
383         alt_req.base = base;
384         alt_req.url = &url;
385         alt_req.buffer = &buffer;
386         alt_req.http_specific = 1;
387         alt_req.slot = slot;
388
389         if (start_active_slot(slot))
390                 run_active_slot(slot);
391         else
392                 cdata->got_alternates = -1;
393
394         strbuf_release(&buffer);
395         strbuf_release(&url);
396 }
397
398 static int fetch_indices(struct walker *walker, struct alt_base *repo)
399 {
400         int ret;
401
402         if (repo->got_indices)
403                 return 0;
404
405         if (walker->get_verbosely)
406                 fprintf(stderr, "Getting pack list for %s\n", repo->base);
407
408         switch (http_get_info_packs(repo->base, &repo->packs)) {
409         case HTTP_OK:
410         case HTTP_MISSING_TARGET:
411                 repo->got_indices = 1;
412                 ret = 0;
413                 break;
414         default:
415                 repo->got_indices = 0;
416                 ret = -1;
417         }
418
419         return ret;
420 }
421
422 static int http_fetch_pack(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
423 {
424         struct packed_git *target;
425         int ret;
426         struct slot_results results;
427         struct http_pack_request *preq;
428
429         if (fetch_indices(walker, repo))
430                 return -1;
431         target = find_sha1_pack(sha1, repo->packs);
432         if (!target)
433                 return -1;
434
435         if (walker->get_verbosely) {
436                 fprintf(stderr, "Getting pack %s\n",
437                         sha1_to_hex(target->sha1));
438                 fprintf(stderr, " which contains %s\n",
439                         sha1_to_hex(sha1));
440         }
441
442         preq = new_http_pack_request(target, repo->base);
443         if (preq == NULL)
444                 goto abort;
445         preq->lst = &repo->packs;
446         preq->slot->results = &results;
447
448         if (start_active_slot(preq->slot)) {
449                 run_active_slot(preq->slot);
450                 if (results.curl_result != CURLE_OK) {
451                         error("Unable to get pack file %s\n%s", preq->url,
452                               curl_errorstr);
453                         goto abort;
454                 }
455         } else {
456                 error("Unable to start request");
457                 goto abort;
458         }
459
460         ret = finish_http_pack_request(preq);
461         release_http_pack_request(preq);
462         if (ret)
463                 return ret;
464
465         return 0;
466
467 abort:
468         return -1;
469 }
470
471 static void abort_object_request(struct object_request *obj_req)
472 {
473         release_object_request(obj_req);
474 }
475
476 static int fetch_object(struct walker *walker, unsigned char *sha1)
477 {
478         char *hex = sha1_to_hex(sha1);
479         int ret = 0;
480         struct object_request *obj_req = NULL;
481         struct http_object_request *req;
482         struct list_head *pos, *head = &object_queue_head;
483
484         list_for_each(pos, head) {
485                 obj_req = list_entry(pos, struct object_request, node);
486                 if (!hashcmp(obj_req->oid.hash, sha1))
487                         break;
488         }
489         if (obj_req == NULL)
490                 return error("Couldn't find request for %s in the queue", hex);
491
492         if (has_sha1_file(obj_req->oid.hash)) {
493                 if (obj_req->req != NULL)
494                         abort_http_object_request(obj_req->req);
495                 abort_object_request(obj_req);
496                 return 0;
497         }
498
499 #ifdef USE_CURL_MULTI
500         while (obj_req->state == WAITING)
501                 step_active_slots();
502 #else
503         start_object_request(walker, obj_req);
504 #endif
505
506         /*
507          * obj_req->req might change when fetching alternates in the callback
508          * process_object_response; therefore, the "shortcut" variable, req,
509          * is used only after we're done with slots.
510          */
511         while (obj_req->state == ACTIVE)
512                 run_active_slot(obj_req->req->slot);
513
514         req = obj_req->req;
515
516         if (req->localfile != -1) {
517                 close(req->localfile);
518                 req->localfile = -1;
519         }
520
521         /*
522          * we turned off CURLOPT_FAILONERROR to avoid losing a
523          * persistent connection and got CURLE_OK.
524          */
525         if (req->http_code >= 300 && req->curl_result == CURLE_OK &&
526                         (starts_with(req->url, "http://") ||
527                          starts_with(req->url, "https://"))) {
528                 req->curl_result = CURLE_HTTP_RETURNED_ERROR;
529                 xsnprintf(req->errorstr, sizeof(req->errorstr),
530                           "HTTP request failed");
531         }
532
533         if (obj_req->state == ABORTED) {
534                 ret = error("Request for %s aborted", hex);
535         } else if (req->curl_result != CURLE_OK &&
536                    req->http_code != 416) {
537                 if (missing_target(req))
538                         ret = -1; /* Be silent, it is probably in a pack. */
539                 else
540                         ret = error("%s (curl_result = %d, http_code = %ld, sha1 = %s)",
541                                     req->errorstr, req->curl_result,
542                                     req->http_code, hex);
543         } else if (req->zret != Z_STREAM_END) {
544                 walker->corrupt_object_found++;
545                 ret = error("File %s (%s) corrupt", hex, req->url);
546         } else if (hashcmp(obj_req->oid.hash, req->real_sha1)) {
547                 ret = error("File %s has bad hash", hex);
548         } else if (req->rename < 0) {
549                 struct strbuf buf = STRBUF_INIT;
550                 sha1_file_name(the_repository, &buf, req->sha1);
551                 ret = error("unable to write sha1 filename %s", buf.buf);
552                 strbuf_release(&buf);
553         }
554
555         release_http_object_request(req);
556         release_object_request(obj_req);
557         return ret;
558 }
559
560 static int fetch(struct walker *walker, unsigned char *sha1)
561 {
562         struct walker_data *data = walker->data;
563         struct alt_base *altbase = data->alt;
564
565         if (!fetch_object(walker, sha1))
566                 return 0;
567         while (altbase) {
568                 if (!http_fetch_pack(walker, altbase, sha1))
569                         return 0;
570                 fetch_alternates(walker, data->alt->base);
571                 altbase = altbase->next;
572         }
573         return error("Unable to find %s under %s", sha1_to_hex(sha1),
574                      data->alt->base);
575 }
576
577 static int fetch_ref(struct walker *walker, struct ref *ref)
578 {
579         struct walker_data *data = walker->data;
580         return http_fetch_ref(data->alt->base, ref);
581 }
582
583 static void cleanup(struct walker *walker)
584 {
585         struct walker_data *data = walker->data;
586         struct alt_base *alt, *alt_next;
587
588         if (data) {
589                 alt = data->alt;
590                 while (alt) {
591                         alt_next = alt->next;
592
593                         free(alt->base);
594                         free(alt);
595
596                         alt = alt_next;
597                 }
598                 free(data);
599                 walker->data = NULL;
600         }
601 }
602
603 struct walker *get_http_walker(const char *url)
604 {
605         char *s;
606         struct walker_data *data = xmalloc(sizeof(struct walker_data));
607         struct walker *walker = xmalloc(sizeof(struct walker));
608
609         data->alt = xmalloc(sizeof(*data->alt));
610         data->alt->base = xstrdup(url);
611         for (s = data->alt->base + strlen(data->alt->base) - 1; *s == '/'; --s)
612                 *s = 0;
613
614         data->alt->got_indices = 0;
615         data->alt->packs = NULL;
616         data->alt->next = NULL;
617         data->got_alternates = -1;
618
619         walker->corrupt_object_found = 0;
620         walker->fetch = fetch;
621         walker->fetch_ref = fetch_ref;
622         walker->prefetch = prefetch;
623         walker->cleanup = cleanup;
624         walker->data = data;
625
626 #ifdef USE_CURL_MULTI
627         add_fill_function(walker, (int (*)(void *)) fill_active_slot);
628 #endif
629
630         return walker;
631 }