Merge branch 'jk/push-deadlock-regression-fix' into maint
[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         for (i = 0; i < ARRAY_SIZE(protocols); i++) {
172                 const char *end;
173                 if (skip_prefix(url, protocols[i], &end) &&
174                     starts_with(end, "://"))
175                         break;
176         }
177
178         if (i >= ARRAY_SIZE(protocols)) {
179                 warning("ignoring alternate with unknown protocol: %s", url);
180                 return 0;
181         }
182         if (!is_transport_allowed(protocols[i], 0)) {
183                 warning("ignoring alternate with restricted protocol: %s", url);
184                 return 0;
185         }
186
187         return 1;
188 }
189
190 static void process_alternates_response(void *callback_data)
191 {
192         struct alternates_request *alt_req =
193                 (struct alternates_request *)callback_data;
194         struct walker *walker = alt_req->walker;
195         struct walker_data *cdata = walker->data;
196         struct active_request_slot *slot = alt_req->slot;
197         struct alt_base *tail = cdata->alt;
198         const char *base = alt_req->base;
199         const char null_byte = '\0';
200         char *data;
201         int i = 0;
202
203         if (alt_req->http_specific) {
204                 if (slot->curl_result != CURLE_OK ||
205                     !alt_req->buffer->len) {
206
207                         /* Try reusing the slot to get non-http alternates */
208                         alt_req->http_specific = 0;
209                         strbuf_reset(alt_req->url);
210                         strbuf_addf(alt_req->url, "%s/objects/info/alternates",
211                                     base);
212                         curl_easy_setopt(slot->curl, CURLOPT_URL,
213                                          alt_req->url->buf);
214                         active_requests++;
215                         slot->in_use = 1;
216                         if (slot->finished != NULL)
217                                 (*slot->finished) = 0;
218                         if (!start_active_slot(slot)) {
219                                 cdata->got_alternates = -1;
220                                 slot->in_use = 0;
221                                 if (slot->finished != NULL)
222                                         (*slot->finished) = 1;
223                         }
224                         return;
225                 }
226         } else if (slot->curl_result != CURLE_OK) {
227                 if (!missing_target(slot)) {
228                         cdata->got_alternates = -1;
229                         return;
230                 }
231         }
232
233         fwrite_buffer((char *)&null_byte, 1, 1, alt_req->buffer);
234         alt_req->buffer->len--;
235         data = alt_req->buffer->buf;
236
237         while (i < alt_req->buffer->len) {
238                 int posn = i;
239                 while (posn < alt_req->buffer->len && data[posn] != '\n')
240                         posn++;
241                 if (data[posn] == '\n') {
242                         int okay = 0;
243                         int serverlen = 0;
244                         struct alt_base *newalt;
245                         if (data[i] == '/') {
246                                 /*
247                                  * This counts
248                                  * http://git.host/pub/scm/linux.git/
249                                  * -----------here^
250                                  * so memcpy(dst, base, serverlen) will
251                                  * copy up to "...git.host".
252                                  */
253                                 const char *colon_ss = strstr(base,"://");
254                                 if (colon_ss) {
255                                         serverlen = (strchr(colon_ss + 3, '/')
256                                                      - base);
257                                         okay = 1;
258                                 }
259                         } else if (!memcmp(data + i, "../", 3)) {
260                                 /*
261                                  * Relative URL; chop the corresponding
262                                  * number of subpath from base (and ../
263                                  * from data), and concatenate the result.
264                                  *
265                                  * The code first drops ../ from data, and
266                                  * then drops one ../ from data and one path
267                                  * from base.  IOW, one extra ../ is dropped
268                                  * from data than path is dropped from base.
269                                  *
270                                  * This is not wrong.  The alternate in
271                                  *     http://git.host/pub/scm/linux.git/
272                                  * to borrow from
273                                  *     http://git.host/pub/scm/linus.git/
274                                  * is ../../linus.git/objects/.  You need
275                                  * two ../../ to borrow from your direct
276                                  * neighbour.
277                                  */
278                                 i += 3;
279                                 serverlen = strlen(base);
280                                 while (i + 2 < posn &&
281                                        !memcmp(data + i, "../", 3)) {
282                                         do {
283                                                 serverlen--;
284                                         } while (serverlen &&
285                                                  base[serverlen - 1] != '/');
286                                         i += 3;
287                                 }
288                                 /* If the server got removed, give up. */
289                                 okay = strchr(base, ':') - base + 3 <
290                                        serverlen;
291                         } else if (alt_req->http_specific) {
292                                 char *colon = strchr(data + i, ':');
293                                 char *slash = strchr(data + i, '/');
294                                 if (colon && slash && colon < data + posn &&
295                                     slash < data + posn && colon < slash) {
296                                         okay = 1;
297                                 }
298                         }
299                         if (okay) {
300                                 struct strbuf target = STRBUF_INIT;
301                                 strbuf_add(&target, base, serverlen);
302                                 strbuf_add(&target, data + i, posn - i);
303                                 if (!strbuf_strip_suffix(&target, "objects")) {
304                                         warning("ignoring alternate that does"
305                                                 " not end in 'objects': %s",
306                                                 target.buf);
307                                         strbuf_release(&target);
308                                 } else if (is_alternate_allowed(target.buf)) {
309                                         warning("adding alternate object store: %s",
310                                                 target.buf);
311                                         newalt = xmalloc(sizeof(*newalt));
312                                         newalt->next = NULL;
313                                         newalt->base = strbuf_detach(&target, NULL);
314                                         newalt->got_indices = 0;
315                                         newalt->packs = NULL;
316
317                                         while (tail->next != NULL)
318                                                 tail = tail->next;
319                                         tail->next = newalt;
320                                 }
321                         }
322                 }
323                 i = posn + 1;
324         }
325
326         cdata->got_alternates = 1;
327 }
328
329 static void fetch_alternates(struct walker *walker, const char *base)
330 {
331         struct strbuf buffer = STRBUF_INIT;
332         struct strbuf url = STRBUF_INIT;
333         struct active_request_slot *slot;
334         struct alternates_request alt_req;
335         struct walker_data *cdata = walker->data;
336
337         if (http_follow_config != HTTP_FOLLOW_ALWAYS)
338                 return;
339
340         /*
341          * If another request has already started fetching alternates,
342          * wait for them to arrive and return to processing this request's
343          * curl message
344          */
345 #ifdef USE_CURL_MULTI
346         while (cdata->got_alternates == 0) {
347                 step_active_slots();
348         }
349 #endif
350
351         /* Nothing to do if they've already been fetched */
352         if (cdata->got_alternates == 1)
353                 return;
354
355         /* Start the fetch */
356         cdata->got_alternates = 0;
357
358         if (walker->get_verbosely)
359                 fprintf(stderr, "Getting alternates list for %s\n", base);
360
361         strbuf_addf(&url, "%s/objects/info/http-alternates", base);
362
363         /*
364          * Use a callback to process the result, since another request
365          * may fail and need to have alternates loaded before continuing
366          */
367         slot = get_active_slot();
368         slot->callback_func = process_alternates_response;
369         alt_req.walker = walker;
370         slot->callback_data = &alt_req;
371
372         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
373         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
374         curl_easy_setopt(slot->curl, CURLOPT_URL, url.buf);
375
376         alt_req.base = base;
377         alt_req.url = &url;
378         alt_req.buffer = &buffer;
379         alt_req.http_specific = 1;
380         alt_req.slot = slot;
381
382         if (start_active_slot(slot))
383                 run_active_slot(slot);
384         else
385                 cdata->got_alternates = -1;
386
387         strbuf_release(&buffer);
388         strbuf_release(&url);
389 }
390
391 static int fetch_indices(struct walker *walker, struct alt_base *repo)
392 {
393         int ret;
394
395         if (repo->got_indices)
396                 return 0;
397
398         if (walker->get_verbosely)
399                 fprintf(stderr, "Getting pack list for %s\n", repo->base);
400
401         switch (http_get_info_packs(repo->base, &repo->packs)) {
402         case HTTP_OK:
403         case HTTP_MISSING_TARGET:
404                 repo->got_indices = 1;
405                 ret = 0;
406                 break;
407         default:
408                 repo->got_indices = 0;
409                 ret = -1;
410         }
411
412         return ret;
413 }
414
415 static int http_fetch_pack(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
416 {
417         struct packed_git *target;
418         int ret;
419         struct slot_results results;
420         struct http_pack_request *preq;
421
422         if (fetch_indices(walker, repo))
423                 return -1;
424         target = find_sha1_pack(sha1, repo->packs);
425         if (!target)
426                 return -1;
427
428         if (walker->get_verbosely) {
429                 fprintf(stderr, "Getting pack %s\n",
430                         sha1_to_hex(target->sha1));
431                 fprintf(stderr, " which contains %s\n",
432                         sha1_to_hex(sha1));
433         }
434
435         preq = new_http_pack_request(target, repo->base);
436         if (preq == NULL)
437                 goto abort;
438         preq->lst = &repo->packs;
439         preq->slot->results = &results;
440
441         if (start_active_slot(preq->slot)) {
442                 run_active_slot(preq->slot);
443                 if (results.curl_result != CURLE_OK) {
444                         error("Unable to get pack file %s\n%s", preq->url,
445                               curl_errorstr);
446                         goto abort;
447                 }
448         } else {
449                 error("Unable to start request");
450                 goto abort;
451         }
452
453         ret = finish_http_pack_request(preq);
454         release_http_pack_request(preq);
455         if (ret)
456                 return ret;
457
458         return 0;
459
460 abort:
461         return -1;
462 }
463
464 static void abort_object_request(struct object_request *obj_req)
465 {
466         release_object_request(obj_req);
467 }
468
469 static int fetch_object(struct walker *walker, unsigned char *sha1)
470 {
471         char *hex = sha1_to_hex(sha1);
472         int ret = 0;
473         struct object_request *obj_req = NULL;
474         struct http_object_request *req;
475         struct list_head *pos, *head = &object_queue_head;
476
477         list_for_each(pos, head) {
478                 obj_req = list_entry(pos, struct object_request, node);
479                 if (!hashcmp(obj_req->sha1, sha1))
480                         break;
481         }
482         if (obj_req == NULL)
483                 return error("Couldn't find request for %s in the queue", hex);
484
485         if (has_sha1_file(obj_req->sha1)) {
486                 if (obj_req->req != NULL)
487                         abort_http_object_request(obj_req->req);
488                 abort_object_request(obj_req);
489                 return 0;
490         }
491
492 #ifdef USE_CURL_MULTI
493         while (obj_req->state == WAITING)
494                 step_active_slots();
495 #else
496         start_object_request(walker, obj_req);
497 #endif
498
499         /*
500          * obj_req->req might change when fetching alternates in the callback
501          * process_object_response; therefore, the "shortcut" variable, req,
502          * is used only after we're done with slots.
503          */
504         while (obj_req->state == ACTIVE)
505                 run_active_slot(obj_req->req->slot);
506
507         req = obj_req->req;
508
509         if (req->localfile != -1) {
510                 close(req->localfile);
511                 req->localfile = -1;
512         }
513
514         /*
515          * we turned off CURLOPT_FAILONERROR to avoid losing a
516          * persistent connection and got CURLE_OK.
517          */
518         if (req->http_code >= 300 && req->curl_result == CURLE_OK &&
519                         (starts_with(req->url, "http://") ||
520                          starts_with(req->url, "https://"))) {
521                 req->curl_result = CURLE_HTTP_RETURNED_ERROR;
522                 xsnprintf(req->errorstr, sizeof(req->errorstr),
523                           "HTTP request failed");
524         }
525
526         if (obj_req->state == ABORTED) {
527                 ret = error("Request for %s aborted", hex);
528         } else if (req->curl_result != CURLE_OK &&
529                    req->http_code != 416) {
530                 if (missing_target(req))
531                         ret = -1; /* Be silent, it is probably in a pack. */
532                 else
533                         ret = error("%s (curl_result = %d, http_code = %ld, sha1 = %s)",
534                                     req->errorstr, req->curl_result,
535                                     req->http_code, hex);
536         } else if (req->zret != Z_STREAM_END) {
537                 walker->corrupt_object_found++;
538                 ret = error("File %s (%s) corrupt", hex, req->url);
539         } else if (hashcmp(obj_req->sha1, req->real_sha1)) {
540                 ret = error("File %s has bad hash", hex);
541         } else if (req->rename < 0) {
542                 ret = error("unable to write sha1 filename %s",
543                             sha1_file_name(req->sha1));
544         }
545
546         release_http_object_request(req);
547         release_object_request(obj_req);
548         return ret;
549 }
550
551 static int fetch(struct walker *walker, unsigned char *sha1)
552 {
553         struct walker_data *data = walker->data;
554         struct alt_base *altbase = data->alt;
555
556         if (!fetch_object(walker, sha1))
557                 return 0;
558         while (altbase) {
559                 if (!http_fetch_pack(walker, altbase, sha1))
560                         return 0;
561                 fetch_alternates(walker, data->alt->base);
562                 altbase = altbase->next;
563         }
564         return error("Unable to find %s under %s", sha1_to_hex(sha1),
565                      data->alt->base);
566 }
567
568 static int fetch_ref(struct walker *walker, struct ref *ref)
569 {
570         struct walker_data *data = walker->data;
571         return http_fetch_ref(data->alt->base, ref);
572 }
573
574 static void cleanup(struct walker *walker)
575 {
576         struct walker_data *data = walker->data;
577         struct alt_base *alt, *alt_next;
578
579         if (data) {
580                 alt = data->alt;
581                 while (alt) {
582                         alt_next = alt->next;
583
584                         free(alt->base);
585                         free(alt);
586
587                         alt = alt_next;
588                 }
589                 free(data);
590                 walker->data = NULL;
591         }
592 }
593
594 struct walker *get_http_walker(const char *url)
595 {
596         char *s;
597         struct walker_data *data = xmalloc(sizeof(struct walker_data));
598         struct walker *walker = xmalloc(sizeof(struct walker));
599
600         data->alt = xmalloc(sizeof(*data->alt));
601         data->alt->base = xstrdup(url);
602         for (s = data->alt->base + strlen(data->alt->base) - 1; *s == '/'; --s)
603                 *s = 0;
604
605         data->alt->got_indices = 0;
606         data->alt->packs = NULL;
607         data->alt->next = NULL;
608         data->got_alternates = -1;
609
610         walker->corrupt_object_found = 0;
611         walker->fetch = fetch;
612         walker->fetch_ref = fetch_ref;
613         walker->prefetch = prefetch;
614         walker->cleanup = cleanup;
615         walker->data = data;
616
617 #ifdef USE_CURL_MULTI
618         add_fill_function(walker, (int (*)(void *)) fill_active_slot);
619 #endif
620
621         return walker;
622 }