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