Give python a chance to find "backported" modules
[git.git] / http-fetch.c
1 #include "cache.h"
2 #include "commit.h"
3 #include "pack.h"
4 #include "fetch.h"
5
6 #include <curl/curl.h>
7 #include <curl/easy.h>
8
9 #if LIBCURL_VERSION_NUM >= 0x070908
10 #define USE_CURL_MULTI
11 #define DEFAULT_MAX_REQUESTS 5
12 #endif
13
14 #if LIBCURL_VERSION_NUM < 0x070704
15 #define curl_global_cleanup() do { /* nothing */ } while(0)
16 #endif
17 #if LIBCURL_VERSION_NUM < 0x070800
18 #define curl_global_init(a) do { /* nothing */ } while(0)
19 #endif
20
21 #if LIBCURL_VERSION_NUM < 0x070c04
22 #define NO_CURL_EASY_DUPHANDLE
23 #endif
24
25 #define PREV_BUF_SIZE 4096
26 #define RANGE_HEADER_SIZE 30
27
28 static int got_alternates = -1;
29 static int active_requests = 0;
30 static int data_received;
31
32 #ifdef USE_CURL_MULTI
33 static int max_requests = -1;
34 static CURLM *curlm;
35 #endif
36 #ifndef NO_CURL_EASY_DUPHANDLE
37 static CURL *curl_default;
38 #endif
39 static struct curl_slist *pragma_header;
40 static struct curl_slist *no_pragma_header;
41 static struct curl_slist *no_range_header;
42 static char curl_errorstr[CURL_ERROR_SIZE];
43
44 struct alt_base
45 {
46         char *base;
47         int got_indices;
48         struct packed_git *packs;
49         struct alt_base *next;
50 };
51
52 static struct alt_base *alt = NULL;
53
54 enum transfer_state {
55         WAITING,
56         ABORTED,
57         ACTIVE,
58         COMPLETE,
59 };
60
61 struct transfer_request
62 {
63         unsigned char sha1[20];
64         struct alt_base *repo;
65         char *url;
66         char filename[PATH_MAX];
67         char tmpfile[PATH_MAX];
68         int local;
69         enum transfer_state state;
70         CURLcode curl_result;
71         char errorstr[CURL_ERROR_SIZE];
72         long http_code;
73         unsigned char real_sha1[20];
74         SHA_CTX c;
75         z_stream stream;
76         int zret;
77         int rename;
78         struct active_request_slot *slot;
79         struct transfer_request *next;
80 };
81
82 struct active_request_slot
83 {
84         CURL *curl;
85         FILE *local;
86         int in_use;
87         int done;
88         CURLcode curl_result;
89         long http_code;
90         void *callback_data;
91         void (*callback_func)(void *data);
92         struct active_request_slot *next;
93 };
94
95 struct alt_request {
96         char *base;
97         char *url;
98         struct buffer *buffer;
99         struct active_request_slot *slot;
100         int http_specific;
101 };
102
103 static struct transfer_request *request_queue_head = NULL;
104 static struct active_request_slot *active_queue_head = NULL;
105
106 static int curl_ssl_verify = -1;
107 static char *ssl_cert = NULL;
108 #if LIBCURL_VERSION_NUM >= 0x070902
109 static char *ssl_key = NULL;
110 #endif
111 #if LIBCURL_VERSION_NUM >= 0x070908
112 static char *ssl_capath = NULL;
113 #endif
114 static char *ssl_cainfo = NULL;
115 static long curl_low_speed_limit = -1;
116 static long curl_low_speed_time = -1;
117
118 struct buffer
119 {
120         size_t posn;
121         size_t size;
122         void *buffer;
123 };
124
125 static int http_options(const char *var, const char *value)
126 {
127         if (!strcmp("http.sslverify", var)) {
128                 if (curl_ssl_verify == -1) {
129                         curl_ssl_verify = git_config_bool(var, value);
130                 }
131                 return 0;
132         }
133
134         if (!strcmp("http.sslcert", var)) {
135                 if (ssl_cert == NULL) {
136                         ssl_cert = xmalloc(strlen(value)+1);
137                         strcpy(ssl_cert, value);
138                 }
139                 return 0;
140         }
141 #if LIBCURL_VERSION_NUM >= 0x070902
142         if (!strcmp("http.sslkey", var)) {
143                 if (ssl_key == NULL) {
144                         ssl_key = xmalloc(strlen(value)+1);
145                         strcpy(ssl_key, value);
146                 }
147                 return 0;
148         }
149 #endif
150 #if LIBCURL_VERSION_NUM >= 0x070908
151         if (!strcmp("http.sslcapath", var)) {
152                 if (ssl_capath == NULL) {
153                         ssl_capath = xmalloc(strlen(value)+1);
154                         strcpy(ssl_capath, value);
155                 }
156                 return 0;
157         }
158 #endif
159         if (!strcmp("http.sslcainfo", var)) {
160                 if (ssl_cainfo == NULL) {
161                         ssl_cainfo = xmalloc(strlen(value)+1);
162                         strcpy(ssl_cainfo, value);
163                 }
164                 return 0;
165         }
166
167 #ifdef USE_CURL_MULTI   
168         if (!strcmp("http.maxrequests", var)) {
169                 if (max_requests == -1)
170                         max_requests = git_config_int(var, value);
171                 return 0;
172         }
173 #endif
174
175         if (!strcmp("http.lowspeedlimit", var)) {
176                 if (curl_low_speed_limit == -1)
177                         curl_low_speed_limit = (long)git_config_int(var, value);
178                 return 0;
179         }
180         if (!strcmp("http.lowspeedtime", var)) {
181                 if (curl_low_speed_time == -1)
182                         curl_low_speed_time = (long)git_config_int(var, value);
183                 return 0;
184         }
185
186         /* Fall back on the default ones */
187         return git_default_config(var, value);
188 }
189
190 static size_t fwrite_buffer(void *ptr, size_t eltsize, size_t nmemb,
191                             struct buffer *buffer)
192 {
193         size_t size = eltsize * nmemb;
194         if (size > buffer->size - buffer->posn)
195                 size = buffer->size - buffer->posn;
196         memcpy(buffer->buffer + buffer->posn, ptr, size);
197         buffer->posn += size;
198         data_received++;
199         return size;
200 }
201
202 static size_t fwrite_buffer_dynamic(const void *ptr, size_t eltsize,
203                                     size_t nmemb, struct buffer *buffer)
204 {
205         size_t size = eltsize * nmemb;
206         if (size > buffer->size - buffer->posn) {
207                 buffer->size = buffer->size * 3 / 2;
208                 if (buffer->size < buffer->posn + size)
209                         buffer->size = buffer->posn + size;
210                 buffer->buffer = xrealloc(buffer->buffer, buffer->size);
211         }
212         memcpy(buffer->buffer + buffer->posn, ptr, size);
213         buffer->posn += size;
214         data_received++;
215         return size;
216 }
217
218 static size_t fwrite_sha1_file(void *ptr, size_t eltsize, size_t nmemb,
219                                void *data)
220 {
221         unsigned char expn[4096];
222         size_t size = eltsize * nmemb;
223         int posn = 0;
224         struct transfer_request *request = (struct transfer_request *)data;
225         do {
226                 ssize_t retval = write(request->local,
227                                        ptr + posn, size - posn);
228                 if (retval < 0)
229                         return posn;
230                 posn += retval;
231         } while (posn < size);
232
233         request->stream.avail_in = size;
234         request->stream.next_in = ptr;
235         do {
236                 request->stream.next_out = expn;
237                 request->stream.avail_out = sizeof(expn);
238                 request->zret = inflate(&request->stream, Z_SYNC_FLUSH);
239                 SHA1_Update(&request->c, expn,
240                             sizeof(expn) - request->stream.avail_out);
241         } while (request->stream.avail_in && request->zret == Z_OK);
242         data_received++;
243         return size;
244 }
245
246 #ifdef USE_CURL_MULTI
247 static void process_curl_messages(void);
248 static void process_request_queue(void);
249 #endif
250 static void fetch_alternates(char *base);
251
252 static CURL* get_curl_handle(void)
253 {
254         CURL* result = curl_easy_init();
255
256         curl_easy_setopt(result, CURLOPT_SSL_VERIFYPEER, curl_ssl_verify);
257 #if LIBCURL_VERSION_NUM >= 0x070907
258         curl_easy_setopt(result, CURLOPT_NETRC, CURL_NETRC_OPTIONAL);
259 #endif
260
261         if (ssl_cert != NULL)
262                 curl_easy_setopt(result, CURLOPT_SSLCERT, ssl_cert);
263 #if LIBCURL_VERSION_NUM >= 0x070902
264         if (ssl_key != NULL)
265                 curl_easy_setopt(result, CURLOPT_SSLKEY, ssl_key);
266 #endif
267 #if LIBCURL_VERSION_NUM >= 0x070908
268         if (ssl_capath != NULL)
269                 curl_easy_setopt(result, CURLOPT_CAPATH, ssl_capath);
270 #endif
271         if (ssl_cainfo != NULL)
272                 curl_easy_setopt(result, CURLOPT_CAINFO, ssl_cainfo);
273         curl_easy_setopt(result, CURLOPT_FAILONERROR, 1);
274
275         if (curl_low_speed_limit > 0 && curl_low_speed_time > 0) {
276                 curl_easy_setopt(result, CURLOPT_LOW_SPEED_LIMIT,
277                                  curl_low_speed_limit);
278                 curl_easy_setopt(result, CURLOPT_LOW_SPEED_TIME,
279                                  curl_low_speed_time);
280         }
281
282         curl_easy_setopt(result, CURLOPT_FOLLOWLOCATION, 1);
283
284         return result;
285 }
286
287 static struct active_request_slot *get_active_slot(void)
288 {
289         struct active_request_slot *slot = active_queue_head;
290         struct active_request_slot *newslot;
291
292 #ifdef USE_CURL_MULTI
293         int num_transfers;
294
295         /* Wait for a slot to open up if the queue is full */
296         while (active_requests >= max_requests) {
297                 curl_multi_perform(curlm, &num_transfers);
298                 if (num_transfers < active_requests) {
299                         process_curl_messages();
300                 }
301         }
302 #endif
303
304         while (slot != NULL && slot->in_use) {
305                 slot = slot->next;
306         }
307         if (slot == NULL) {
308                 newslot = xmalloc(sizeof(*newslot));
309                 newslot->curl = NULL;
310                 newslot->in_use = 0;
311                 newslot->next = NULL;
312
313                 slot = active_queue_head;
314                 if (slot == NULL) {
315                         active_queue_head = newslot;
316                 } else {
317                         while (slot->next != NULL) {
318                                 slot = slot->next;
319                         }
320                         slot->next = newslot;
321                 }
322                 slot = newslot;
323         }
324
325         if (slot->curl == NULL) {
326 #ifdef NO_CURL_EASY_DUPHANDLE
327                 slot->curl = get_curl_handle();
328 #else
329                 slot->curl = curl_easy_duphandle(curl_default);
330 #endif
331         }
332
333         active_requests++;
334         slot->in_use = 1;
335         slot->done = 0;
336         slot->local = NULL;
337         slot->callback_data = NULL;
338         slot->callback_func = NULL;
339         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, pragma_header);
340         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_range_header);
341         curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, curl_errorstr);
342
343         return slot;
344 }
345
346 static int start_active_slot(struct active_request_slot *slot)
347 {
348 #ifdef USE_CURL_MULTI
349         CURLMcode curlm_result = curl_multi_add_handle(curlm, slot->curl);
350
351         if (curlm_result != CURLM_OK &&
352             curlm_result != CURLM_CALL_MULTI_PERFORM) {
353                 active_requests--;
354                 slot->in_use = 0;
355                 return 0;
356         }
357 #endif
358         return 1;
359 }
360
361 static void run_active_slot(struct active_request_slot *slot)
362 {
363 #ifdef USE_CURL_MULTI
364         int num_transfers;
365         long last_pos = 0;
366         long current_pos;
367         fd_set readfds;
368         fd_set writefds;
369         fd_set excfds;
370         int max_fd;
371         struct timeval select_timeout;
372         CURLMcode curlm_result;
373
374         while (!slot->done) {
375                 data_received = 0;
376                 do {
377                         curlm_result = curl_multi_perform(curlm,
378                                                           &num_transfers);
379                 } while (curlm_result == CURLM_CALL_MULTI_PERFORM);
380                 if (num_transfers < active_requests) {
381                         process_curl_messages();
382                         process_request_queue();
383                 }
384
385                 if (!data_received && slot->local != NULL) {
386                         current_pos = ftell(slot->local);
387                         if (current_pos > last_pos)
388                                 data_received++;
389                         last_pos = current_pos;
390                 }
391
392                 if (!slot->done && !data_received) {
393                         max_fd = 0;
394                         FD_ZERO(&readfds);
395                         FD_ZERO(&writefds);
396                         FD_ZERO(&excfds);
397                         select_timeout.tv_sec = 0;
398                         select_timeout.tv_usec = 50000;
399                         select(max_fd, &readfds, &writefds,
400                                &excfds, &select_timeout);
401                 }
402         }
403 #else
404         slot->curl_result = curl_easy_perform(slot->curl);
405         active_requests--;
406 #endif
407 }
408
409 static void start_request(struct transfer_request *request)
410 {
411         char *hex = sha1_to_hex(request->sha1);
412         char prevfile[PATH_MAX];
413         char *url;
414         char *posn;
415         int prevlocal;
416         unsigned char prev_buf[PREV_BUF_SIZE];
417         ssize_t prev_read = 0;
418         long prev_posn = 0;
419         char range[RANGE_HEADER_SIZE];
420         struct curl_slist *range_header = NULL;
421         struct active_request_slot *slot;
422
423         snprintf(prevfile, sizeof(prevfile), "%s.prev", request->filename);
424         unlink(prevfile);
425         rename(request->tmpfile, prevfile);
426         unlink(request->tmpfile);
427
428         if (request->local != -1)
429                 error("fd leakage in start: %d", request->local);
430         request->local = open(request->tmpfile,
431                               O_WRONLY | O_CREAT | O_EXCL, 0666);
432         /* This could have failed due to the "lazy directory creation";
433          * try to mkdir the last path component.
434          */
435         if (request->local < 0 && errno == ENOENT) {
436                 char *dir = strrchr(request->tmpfile, '/');
437                 if (dir) {
438                         *dir = 0;
439                         mkdir(request->tmpfile, 0777);
440                         *dir = '/';
441                 }
442                 request->local = open(request->tmpfile,
443                                       O_WRONLY | O_CREAT | O_EXCL, 0666);
444         }
445
446         if (request->local < 0) {
447                 request->state = ABORTED;
448                 error("Couldn't create temporary file %s for %s: %s\n",
449                       request->tmpfile, request->filename, strerror(errno));
450                 return;
451         }
452
453         memset(&request->stream, 0, sizeof(request->stream));
454
455         inflateInit(&request->stream);
456
457         SHA1_Init(&request->c);
458
459         url = xmalloc(strlen(request->repo->base) + 50);
460         request->url = xmalloc(strlen(request->repo->base) + 50);
461         strcpy(url, request->repo->base);
462         posn = url + strlen(request->repo->base);
463         strcpy(posn, "objects/");
464         posn += 8;
465         memcpy(posn, hex, 2);
466         posn += 2;
467         *(posn++) = '/';
468         strcpy(posn, hex + 2);
469         strcpy(request->url, url);
470
471         /* If a previous temp file is present, process what was already
472            fetched. */
473         prevlocal = open(prevfile, O_RDONLY);
474         if (prevlocal != -1) {
475                 do {
476                         prev_read = read(prevlocal, prev_buf, PREV_BUF_SIZE);
477                         if (prev_read>0) {
478                                 if (fwrite_sha1_file(prev_buf,
479                                                      1,
480                                                      prev_read,
481                                                      request) == prev_read) {
482                                         prev_posn += prev_read;
483                                 } else {
484                                         prev_read = -1;
485                                 }
486                         }
487                 } while (prev_read > 0);
488                 close(prevlocal);
489         }
490         unlink(prevfile);
491
492         /* Reset inflate/SHA1 if there was an error reading the previous temp
493            file; also rewind to the beginning of the local file. */
494         if (prev_read == -1) {
495                 memset(&request->stream, 0, sizeof(request->stream));
496                 inflateInit(&request->stream);
497                 SHA1_Init(&request->c);
498                 if (prev_posn>0) {
499                         prev_posn = 0;
500                         lseek(request->local, SEEK_SET, 0);
501                         ftruncate(request->local, 0);
502                 }
503         }
504
505         slot = get_active_slot();
506         curl_easy_setopt(slot->curl, CURLOPT_FILE, request);
507         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
508         curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, request->errorstr);
509         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
510         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
511
512         /* If we have successfully processed data from a previous fetch
513            attempt, only fetch the data we don't already have. */
514         if (prev_posn>0) {
515                 if (get_verbosely)
516                         fprintf(stderr,
517                                 "Resuming fetch of object %s at byte %ld\n",
518                                 hex, prev_posn);
519                 sprintf(range, "Range: bytes=%ld-", prev_posn);
520                 range_header = curl_slist_append(range_header, range);
521                 curl_easy_setopt(slot->curl,
522                                  CURLOPT_HTTPHEADER, range_header);
523         }
524
525         /* Try to get the request started, abort the request on error */
526         if (!start_active_slot(slot)) {
527                 request->state = ABORTED;
528                 close(request->local); request->local = -1;
529                 free(request->url);
530                 return;
531         }
532         
533         request->slot = slot;
534         request->state = ACTIVE;
535 }
536
537 static void finish_request(struct transfer_request *request)
538 {
539         struct stat st;
540
541         fchmod(request->local, 0444);
542         close(request->local); request->local = -1;
543
544         if (request->http_code == 416) {
545                 fprintf(stderr, "Warning: requested range invalid; we may already have all the data.\n");
546         } else if (request->curl_result != CURLE_OK) {
547                 if (stat(request->tmpfile, &st) == 0)
548                         if (st.st_size == 0)
549                                 unlink(request->tmpfile);
550                 return;
551         }
552
553         inflateEnd(&request->stream);
554         SHA1_Final(request->real_sha1, &request->c);
555         if (request->zret != Z_STREAM_END) {
556                 unlink(request->tmpfile);
557                 return;
558         }
559         if (memcmp(request->sha1, request->real_sha1, 20)) {
560                 unlink(request->tmpfile);
561                 return;
562         }
563         request->rename =
564                 move_temp_to_file(request->tmpfile, request->filename);
565
566         if (request->rename == 0)
567                 pull_say("got %s\n", sha1_to_hex(request->sha1));
568 }
569
570 static void release_request(struct transfer_request *request)
571 {
572         struct transfer_request *entry = request_queue_head;
573
574         if (request->local != -1)
575                 error("fd leakage in release: %d", request->local);
576         if (request == request_queue_head) {
577                 request_queue_head = request->next;
578         } else {
579                 while (entry->next != NULL && entry->next != request)
580                         entry = entry->next;
581                 if (entry->next == request)
582                         entry->next = entry->next->next;
583         }
584
585         free(request->url);
586         free(request);
587 }
588
589 #ifdef USE_CURL_MULTI
590 static void process_curl_messages(void)
591 {
592         int num_messages;
593         struct active_request_slot *slot;
594         struct transfer_request *request = NULL;
595         CURLMsg *curl_message = curl_multi_info_read(curlm, &num_messages);
596
597         while (curl_message != NULL) {
598                 if (curl_message->msg == CURLMSG_DONE) {
599                         int curl_result = curl_message->data.result;
600                         slot = active_queue_head;
601                         while (slot != NULL &&
602                                slot->curl != curl_message->easy_handle)
603                                 slot = slot->next;
604                         if (slot != NULL) {
605                                 curl_multi_remove_handle(curlm, slot->curl);
606                                 active_requests--;
607                                 slot->done = 1;
608                                 slot->in_use = 0;
609                                 slot->curl_result = curl_result;
610                                 curl_easy_getinfo(slot->curl,
611                                                   CURLINFO_HTTP_CODE,
612                                                   &slot->http_code);
613                                 request = request_queue_head;
614                                 while (request != NULL &&
615                                        request->slot != slot)
616                                         request = request->next;
617                         } else {
618                                 fprintf(stderr, "Received DONE message for unknown request!\n");
619                         }
620
621                         /* Process slot callback if appropriate */
622                         if (slot->callback_func != NULL) {
623                                 slot->callback_func(slot->callback_data);
624                         }
625
626                         if (request != NULL) {
627                                 request->curl_result = curl_result;
628                                 request->http_code = slot->http_code;
629                                 request->slot = NULL;
630                                 request->state = COMPLETE;
631
632                                 /* Use alternates if necessary */
633                                 if (request->http_code == 404) {
634                                         fetch_alternates(alt->base);
635                                         if (request->repo->next != NULL) {
636                                                 request->repo =
637                                                         request->repo->next;
638                                                 close(request->local);
639                                                         request->local = -1;
640                                                 start_request(request);
641                                         } else {
642                                                 finish_request(request);
643                                         }
644                                 } else {
645                                         finish_request(request);
646                                 }
647                         }
648                 } else {
649                         fprintf(stderr, "Unknown CURL message received: %d\n",
650                                 (int)curl_message->msg);
651                 }
652                 curl_message = curl_multi_info_read(curlm, &num_messages);
653         }
654 }
655
656 static void process_request_queue(void)
657 {
658         struct transfer_request *request = request_queue_head;
659         struct active_request_slot *slot = active_queue_head;
660         int num_transfers;
661
662         while (active_requests < max_requests && request != NULL) {
663                 if (request->state == WAITING) {
664                         if (has_sha1_file(request->sha1))
665                                 release_request(request);
666                         else
667                                 start_request(request);
668                         curl_multi_perform(curlm, &num_transfers);
669                 }
670                 request = request->next;
671         }
672
673         while (slot != NULL) {
674                 if (!slot->in_use && slot->curl != NULL) {
675                         curl_easy_cleanup(slot->curl);
676                         slot->curl = NULL;
677                 }
678                 slot = slot->next;
679         }                               
680 }
681 #endif
682
683 void prefetch(unsigned char *sha1)
684 {
685         struct transfer_request *newreq;
686         struct transfer_request *tail;
687         char *filename = sha1_file_name(sha1);
688
689         newreq = xmalloc(sizeof(*newreq));
690         memcpy(newreq->sha1, sha1, 20);
691         newreq->repo = alt;
692         newreq->url = NULL;
693         newreq->local = -1;
694         newreq->state = WAITING;
695         snprintf(newreq->filename, sizeof(newreq->filename), "%s", filename);
696         snprintf(newreq->tmpfile, sizeof(newreq->tmpfile),
697                  "%s.temp", filename);
698         newreq->next = NULL;
699
700         if (request_queue_head == NULL) {
701                 request_queue_head = newreq;
702         } else {
703                 tail = request_queue_head;
704                 while (tail->next != NULL) {
705                         tail = tail->next;
706                 }
707                 tail->next = newreq;
708         }
709 #ifdef USE_CURL_MULTI
710         process_request_queue();
711         process_curl_messages();
712 #endif
713 }
714
715 static int fetch_index(struct alt_base *repo, unsigned char *sha1)
716 {
717         char *hex = sha1_to_hex(sha1);
718         char *filename;
719         char *url;
720         char tmpfile[PATH_MAX];
721         long prev_posn = 0;
722         char range[RANGE_HEADER_SIZE];
723         struct curl_slist *range_header = NULL;
724
725         FILE *indexfile;
726         struct active_request_slot *slot;
727
728         if (has_pack_index(sha1))
729                 return 0;
730
731         if (get_verbosely)
732                 fprintf(stderr, "Getting index for pack %s\n", hex);
733         
734         url = xmalloc(strlen(repo->base) + 64);
735         sprintf(url, "%s/objects/pack/pack-%s.idx", repo->base, hex);
736         
737         filename = sha1_pack_index_name(sha1);
738         snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
739         indexfile = fopen(tmpfile, "a");
740         if (!indexfile)
741                 return error("Unable to open local file %s for pack index",
742                              filename);
743
744         slot = get_active_slot();
745         curl_easy_setopt(slot->curl, CURLOPT_FILE, indexfile);
746         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
747         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
748         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
749         slot->local = indexfile;
750
751         /* If there is data present from a previous transfer attempt,
752            resume where it left off */
753         prev_posn = ftell(indexfile);
754         if (prev_posn>0) {
755                 if (get_verbosely)
756                         fprintf(stderr,
757                                 "Resuming fetch of index for pack %s at byte %ld\n",
758                                 hex, prev_posn);
759                 sprintf(range, "Range: bytes=%ld-", prev_posn);
760                 range_header = curl_slist_append(range_header, range);
761                 curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
762         }
763
764         if (start_active_slot(slot)) {
765                 run_active_slot(slot);
766                 if (slot->curl_result != CURLE_OK) {
767                         fclose(indexfile);
768                         return error("Unable to get pack index %s\n%s", url,
769                                      curl_errorstr);
770                 }
771         } else {
772                 fclose(indexfile);
773                 return error("Unable to start request");
774         }
775
776         fclose(indexfile);
777
778         return move_temp_to_file(tmpfile, filename);
779 }
780
781 static int setup_index(struct alt_base *repo, unsigned char *sha1)
782 {
783         struct packed_git *new_pack;
784         if (has_pack_file(sha1))
785                 return 0; // don't list this as something we can get
786
787         if (fetch_index(repo, sha1))
788                 return -1;
789
790         new_pack = parse_pack_index(sha1);
791         new_pack->next = repo->packs;
792         repo->packs = new_pack;
793         return 0;
794 }
795
796 static void process_alternates(void *callback_data)
797 {
798         struct alt_request *alt_req = (struct alt_request *)callback_data;
799         struct active_request_slot *slot = alt_req->slot;
800         struct alt_base *tail = alt;
801         char *base = alt_req->base;
802         static const char null_byte = '\0';
803         char *data;
804         int i = 0;
805
806         if (alt_req->http_specific) {
807                 if (slot->curl_result != CURLE_OK ||
808                     !alt_req->buffer->posn) {
809
810                         /* Try reusing the slot to get non-http alternates */
811                         alt_req->http_specific = 0;
812                         sprintf(alt_req->url, "%s/objects/info/alternates",
813                                 base);
814                         curl_easy_setopt(slot->curl, CURLOPT_URL,
815                                          alt_req->url);
816                         active_requests++;
817                         slot->in_use = 1;
818                         slot->done = 0;
819                         if (start_active_slot(slot)) {
820                                 return;
821                         } else {
822                                 got_alternates = -1;
823                                 slot->done = 1;
824                                 return;
825                         }
826                 }
827         } else if (slot->curl_result != CURLE_OK) {
828                 if (slot->http_code != 404) {
829                         got_alternates = -1;
830                         return;
831                 }
832         }
833
834         fwrite_buffer_dynamic(&null_byte, 1, 1, alt_req->buffer);
835         alt_req->buffer->posn--;
836         data = alt_req->buffer->buffer;
837
838         while (i < alt_req->buffer->posn) {
839                 int posn = i;
840                 while (posn < alt_req->buffer->posn && data[posn] != '\n')
841                         posn++;
842                 if (data[posn] == '\n') {
843                         int okay = 0;
844                         int serverlen = 0;
845                         struct alt_base *newalt;
846                         char *target = NULL;
847                         if (data[i] == '/') {
848                                 serverlen = strchr(base + 8, '/') - base;
849                                 okay = 1;
850                         } else if (!memcmp(data + i, "../", 3)) {
851                                 i += 3;
852                                 serverlen = strlen(base);
853                                 while (i + 2 < posn && 
854                                        !memcmp(data + i, "../", 3)) {
855                                         do {
856                                                 serverlen--;
857                                         } while (serverlen &&
858                                                  base[serverlen - 1] != '/');
859                                         i += 3;
860                                 }
861                                 // If the server got removed, give up.
862                                 okay = strchr(base, ':') - base + 3 < 
863                                         serverlen;
864                         } else if (alt_req->http_specific) {
865                                 char *colon = strchr(data + i, ':');
866                                 char *slash = strchr(data + i, '/');
867                                 if (colon && slash && colon < data + posn &&
868                                     slash < data + posn && colon < slash) {
869                                         okay = 1;
870                                 }
871                         }
872                         // skip 'objects' at end
873                         if (okay) {
874                                 target = xmalloc(serverlen + posn - i - 6);
875                                 strncpy(target, base, serverlen);
876                                 strncpy(target + serverlen, data + i,
877                                         posn - i - 7);
878                                 target[serverlen + posn - i - 7] = '\0';
879                                 if (get_verbosely)
880                                         fprintf(stderr, 
881                                                 "Also look at %s\n", target);
882                                 newalt = xmalloc(sizeof(*newalt));
883                                 newalt->next = NULL;
884                                 newalt->base = target;
885                                 newalt->got_indices = 0;
886                                 newalt->packs = NULL;
887                                 while (tail->next != NULL)
888                                         tail = tail->next;
889                                 tail->next = newalt;
890                         }
891                 }
892                 i = posn + 1;
893         }
894
895         got_alternates = 1;
896 }
897
898 static void fetch_alternates(char *base)
899 {
900         struct buffer buffer;
901         char *url;
902         char *data;
903         struct active_request_slot *slot;
904         static struct alt_request alt_req;
905         int num_transfers;
906
907         /* If another request has already started fetching alternates,
908            wait for them to arrive and return to processing this request's
909            curl message */
910         while (got_alternates == 0) {
911                 curl_multi_perform(curlm, &num_transfers);
912                 process_curl_messages();
913                 process_request_queue();
914         }
915
916         /* Nothing to do if they've already been fetched */
917         if (got_alternates == 1)
918                 return;
919
920         /* Start the fetch */
921         got_alternates = 0;
922
923         data = xmalloc(4096);
924         buffer.size = 4096;
925         buffer.posn = 0;
926         buffer.buffer = data;
927
928         if (get_verbosely)
929                 fprintf(stderr, "Getting alternates list for %s\n", base);
930         
931         url = xmalloc(strlen(base) + 31);
932         sprintf(url, "%s/objects/info/http-alternates", base);
933
934         /* Use a callback to process the result, since another request
935            may fail and need to have alternates loaded before continuing */
936         slot = get_active_slot();
937         slot->callback_func = process_alternates;
938         slot->callback_data = &alt_req;
939
940         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
941         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
942                          fwrite_buffer_dynamic);
943         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
944
945         alt_req.base = base;
946         alt_req.url = url;
947         alt_req.buffer = &buffer;
948         alt_req.http_specific = 1;
949         alt_req.slot = slot;
950
951         if (start_active_slot(slot))
952                 run_active_slot(slot);
953         else
954                 got_alternates = -1;
955
956         free(data);
957         free(url);
958 }
959
960 static int fetch_indices(struct alt_base *repo)
961 {
962         unsigned char sha1[20];
963         char *url;
964         struct buffer buffer;
965         char *data;
966         int i = 0;
967
968         struct active_request_slot *slot;
969
970         if (repo->got_indices)
971                 return 0;
972
973         data = xmalloc(4096);
974         buffer.size = 4096;
975         buffer.posn = 0;
976         buffer.buffer = data;
977
978         if (get_verbosely)
979                 fprintf(stderr, "Getting pack list for %s\n", repo->base);
980         
981         url = xmalloc(strlen(repo->base) + 21);
982         sprintf(url, "%s/objects/info/packs", repo->base);
983
984         slot = get_active_slot();
985         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
986         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
987                          fwrite_buffer_dynamic);
988         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
989         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
990         if (start_active_slot(slot)) {
991                 run_active_slot(slot);
992                 if (slot->curl_result != CURLE_OK) {
993                         free(buffer.buffer);
994                         return error("%s", curl_errorstr);
995                 }
996         } else {
997                 free(buffer.buffer);
998                 return error("Unable to start request");
999         }
1000
1001         data = buffer.buffer;
1002         while (i < buffer.posn) {
1003                 switch (data[i]) {
1004                 case 'P':
1005                         i++;
1006                         if (i + 52 < buffer.posn &&
1007                             !strncmp(data + i, " pack-", 6) &&
1008                             !strncmp(data + i + 46, ".pack\n", 6)) {
1009                                 get_sha1_hex(data + i + 6, sha1);
1010                                 setup_index(repo, sha1);
1011                                 i += 51;
1012                                 break;
1013                         }
1014                 default:
1015                         while (data[i] != '\n')
1016                                 i++;
1017                 }
1018                 i++;
1019         }
1020
1021         free(buffer.buffer);
1022         repo->got_indices = 1;
1023         return 0;
1024 }
1025
1026 static int fetch_pack(struct alt_base *repo, unsigned char *sha1)
1027 {
1028         char *url;
1029         struct packed_git *target;
1030         struct packed_git **lst;
1031         FILE *packfile;
1032         char *filename;
1033         char tmpfile[PATH_MAX];
1034         int ret;
1035         long prev_posn = 0;
1036         char range[RANGE_HEADER_SIZE];
1037         struct curl_slist *range_header = NULL;
1038
1039         struct active_request_slot *slot;
1040
1041         if (fetch_indices(repo))
1042                 return -1;
1043         target = find_sha1_pack(sha1, repo->packs);
1044         if (!target)
1045                 return -1;
1046
1047         if (get_verbosely) {
1048                 fprintf(stderr, "Getting pack %s\n",
1049                         sha1_to_hex(target->sha1));
1050                 fprintf(stderr, " which contains %s\n",
1051                         sha1_to_hex(sha1));
1052         }
1053
1054         url = xmalloc(strlen(repo->base) + 65);
1055         sprintf(url, "%s/objects/pack/pack-%s.pack",
1056                 repo->base, sha1_to_hex(target->sha1));
1057
1058         filename = sha1_pack_name(target->sha1);
1059         snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
1060         packfile = fopen(tmpfile, "a");
1061         if (!packfile)
1062                 return error("Unable to open local file %s for pack",
1063                              filename);
1064
1065         slot = get_active_slot();
1066         curl_easy_setopt(slot->curl, CURLOPT_FILE, packfile);
1067         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
1068         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
1069         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
1070         slot->local = packfile;
1071
1072         /* If there is data present from a previous transfer attempt,
1073            resume where it left off */
1074         prev_posn = ftell(packfile);
1075         if (prev_posn>0) {
1076                 if (get_verbosely)
1077                         fprintf(stderr,
1078                                 "Resuming fetch of pack %s at byte %ld\n",
1079                                 sha1_to_hex(target->sha1), prev_posn);
1080                 sprintf(range, "Range: bytes=%ld-", prev_posn);
1081                 range_header = curl_slist_append(range_header, range);
1082                 curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
1083         }
1084
1085         if (start_active_slot(slot)) {
1086                 run_active_slot(slot);
1087                 if (slot->curl_result != CURLE_OK) {
1088                         fclose(packfile);
1089                         return error("Unable to get pack file %s\n%s", url,
1090                                      curl_errorstr);
1091                 }
1092         } else {
1093                 fclose(packfile);
1094                 return error("Unable to start request");
1095         }
1096
1097         fclose(packfile);
1098
1099         ret = move_temp_to_file(tmpfile, filename);
1100         if (ret)
1101                 return ret;
1102
1103         lst = &repo->packs;
1104         while (*lst != target)
1105                 lst = &((*lst)->next);
1106         *lst = (*lst)->next;
1107
1108         if (verify_pack(target, 0))
1109                 return -1;
1110         install_packed_git(target);
1111
1112         return 0;
1113 }
1114
1115 static int fetch_object(struct alt_base *repo, unsigned char *sha1)
1116 {
1117         char *hex = sha1_to_hex(sha1);
1118         int ret;
1119         struct transfer_request *request = request_queue_head;
1120
1121         while (request != NULL && memcmp(request->sha1, sha1, 20))
1122                 request = request->next;
1123         if (request == NULL)
1124                 return error("Couldn't find request for %s in the queue", hex);
1125
1126         if (has_sha1_file(request->sha1)) {
1127                 release_request(request);
1128                 return 0;
1129         }
1130
1131 #ifdef USE_CURL_MULTI
1132         while (request->state == WAITING) {
1133                 int num_transfers;
1134                 curl_multi_perform(curlm, &num_transfers);
1135                 if (num_transfers < active_requests) {
1136                         process_curl_messages();
1137                         process_request_queue();
1138                 }
1139         }
1140 #else
1141         start_request(request);
1142 #endif
1143
1144         while (request->state == ACTIVE) {
1145                 run_active_slot(request->slot);
1146 #ifndef USE_CURL_MULTI
1147                 request->curl_result = request->slot->curl_result;
1148                 request->http_code = request->slot->http_code;
1149                 request->slot = NULL;
1150
1151                 /* Use alternates if necessary */
1152                 if (request->http_code == 404) {
1153                         fetch_alternates(alt->base);
1154                         if (request->repo->next != NULL) {
1155                                 request->repo = request->repo->next;
1156                                 close(request->local); request->local = -1;
1157                                 start_request(request);
1158                         }
1159                 } else {
1160                         finish_request(request);
1161                         request->state = COMPLETE;
1162                 }
1163 #endif
1164         }
1165         if (request->local != -1) {
1166                 close(request->local); request->local = -1;
1167         }
1168
1169         if (request->state == ABORTED) {
1170                 release_request(request);
1171                 return error("Request for %s aborted", hex);
1172         }
1173
1174         if (request->curl_result != CURLE_OK && request->http_code != 416) {
1175                 if (request->http_code == 404)
1176                         ret = -1; /* Be silent, it is probably in a pack. */
1177                 else
1178                         ret = error("%s (curl_result = %d, http_code = %ld, sha1 = %s)",
1179                                     request->errorstr, request->curl_result,
1180                                     request->http_code, hex);
1181                 release_request(request);
1182                 return ret;
1183         }
1184
1185         if (request->zret != Z_STREAM_END) {
1186                 ret = error("File %s (%s) corrupt\n", hex, request->url);
1187                 release_request(request);
1188                 return ret;
1189         }
1190
1191         if (memcmp(request->sha1, request->real_sha1, 20)) {
1192                 release_request(request);
1193                 return error("File %s has bad hash\n", hex);
1194         }
1195
1196         if (request->rename < 0) {
1197                 ret = error("unable to write sha1 filename %s: %s",
1198                             request->filename,
1199                             strerror(request->rename));
1200                 release_request(request);
1201                 return ret;
1202         }
1203
1204         release_request(request);
1205         return 0;
1206 }
1207
1208 int fetch(unsigned char *sha1)
1209 {
1210         struct alt_base *altbase = alt;
1211
1212         if (!fetch_object(altbase, sha1))
1213                 return 0;
1214         while (altbase) {
1215                 if (!fetch_pack(altbase, sha1))
1216                         return 0;
1217                 fetch_alternates(alt->base);
1218                 altbase = altbase->next;
1219         }
1220         return error("Unable to find %s under %s\n", sha1_to_hex(sha1), 
1221                      alt->base);
1222 }
1223
1224 static inline int needs_quote(int ch)
1225 {
1226         switch (ch) {
1227         case '/': case '-': case '.':
1228         case 'A'...'Z': case 'a'...'z': case '0'...'9':
1229                 return 0;
1230         default:
1231                 return 1;
1232         }
1233 }
1234
1235 static inline int hex(int v)
1236 {
1237         if (v < 10) return '0' + v;
1238         else return 'A' + v - 10;
1239 }
1240
1241 static char *quote_ref_url(const char *base, const char *ref)
1242 {
1243         const char *cp;
1244         char *dp, *qref;
1245         int len, baselen, ch;
1246
1247         baselen = strlen(base);
1248         len = baselen + 6; /* "refs/" + NUL */
1249         for (cp = ref; (ch = *cp) != 0; cp++, len++)
1250                 if (needs_quote(ch))
1251                         len += 2; /* extra two hex plus replacement % */
1252         qref = xmalloc(len);
1253         memcpy(qref, base, baselen);
1254         memcpy(qref + baselen, "refs/", 5);
1255         for (cp = ref, dp = qref + baselen + 5; (ch = *cp) != 0; cp++) {
1256                 if (needs_quote(ch)) {
1257                         *dp++ = '%';
1258                         *dp++ = hex((ch >> 4) & 0xF);
1259                         *dp++ = hex(ch & 0xF);
1260                 }
1261                 else
1262                         *dp++ = ch;
1263         }
1264         *dp = 0;
1265
1266         return qref;
1267 }
1268
1269 int fetch_ref(char *ref, unsigned char *sha1)
1270 {
1271         char *url;
1272         char hex[42];
1273         struct buffer buffer;
1274         char *base = alt->base;
1275         struct active_request_slot *slot;
1276         buffer.size = 41;
1277         buffer.posn = 0;
1278         buffer.buffer = hex;
1279         hex[41] = '\0';
1280         
1281         url = quote_ref_url(base, ref);
1282         slot = get_active_slot();
1283         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
1284         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
1285         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
1286         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
1287         if (start_active_slot(slot)) {
1288                 run_active_slot(slot);
1289                 if (slot->curl_result != CURLE_OK)
1290                         return error("Couldn't get %s for %s\n%s",
1291                                      url, ref, curl_errorstr);
1292         } else {
1293                 return error("Unable to start request");
1294         }
1295
1296         hex[40] = '\0';
1297         get_sha1_hex(hex, sha1);
1298         return 0;
1299 }
1300
1301 int main(int argc, char **argv)
1302 {
1303         char *commit_id;
1304         char *url;
1305         int arg = 1;
1306         struct active_request_slot *slot;
1307         char *low_speed_limit;
1308         char *low_speed_time;
1309         char *wait_url;
1310         int rc = 0;
1311
1312         while (arg < argc && argv[arg][0] == '-') {
1313                 if (argv[arg][1] == 't') {
1314                         get_tree = 1;
1315                 } else if (argv[arg][1] == 'c') {
1316                         get_history = 1;
1317                 } else if (argv[arg][1] == 'a') {
1318                         get_all = 1;
1319                         get_tree = 1;
1320                         get_history = 1;
1321                 } else if (argv[arg][1] == 'v') {
1322                         get_verbosely = 1;
1323                 } else if (argv[arg][1] == 'w') {
1324                         write_ref = argv[arg + 1];
1325                         arg++;
1326                 } else if (!strcmp(argv[arg], "--recover")) {
1327                         get_recover = 1;
1328                 }
1329                 arg++;
1330         }
1331         if (argc < arg + 2) {
1332                 usage("git-http-fetch [-c] [-t] [-a] [-d] [-v] [--recover] [-w ref] commit-id url");
1333                 return 1;
1334         }
1335         commit_id = argv[arg];
1336         url = argv[arg + 1];
1337
1338         curl_global_init(CURL_GLOBAL_ALL);
1339
1340 #ifdef USE_CURL_MULTI
1341         {
1342                 char *http_max_requests = getenv("GIT_HTTP_MAX_REQUESTS");
1343                 if (http_max_requests != NULL)
1344                         max_requests = atoi(http_max_requests);
1345         }
1346
1347         curlm = curl_multi_init();
1348         if (curlm == NULL) {
1349                 fprintf(stderr, "Error creating curl multi handle.\n");
1350                 return 1;
1351         }
1352 #endif
1353
1354         if (getenv("GIT_SSL_NO_VERIFY"))
1355                 curl_ssl_verify = 0;
1356
1357         ssl_cert = getenv("GIT_SSL_CERT");
1358 #if LIBCURL_VERSION_NUM >= 0x070902
1359         ssl_key = getenv("GIT_SSL_KEY");
1360 #endif
1361 #if LIBCURL_VERSION_NUM >= 0x070908
1362         ssl_capath = getenv("GIT_SSL_CAPATH");
1363 #endif
1364         ssl_cainfo = getenv("GIT_SSL_CAINFO");
1365
1366         low_speed_limit = getenv("GIT_HTTP_LOW_SPEED_LIMIT");
1367         if (low_speed_limit != NULL)
1368                 curl_low_speed_limit = strtol(low_speed_limit, NULL, 10);
1369         low_speed_time = getenv("GIT_HTTP_LOW_SPEED_TIME");
1370         if (low_speed_time != NULL)
1371                 curl_low_speed_time = strtol(low_speed_time, NULL, 10);
1372
1373         git_config(http_options);
1374
1375         if (curl_ssl_verify == -1)
1376                 curl_ssl_verify = 1;
1377
1378 #ifdef USE_CURL_MULTI
1379         if (max_requests < 1)
1380                 max_requests = DEFAULT_MAX_REQUESTS;
1381 #endif
1382
1383         pragma_header = curl_slist_append(pragma_header, "Pragma: no-cache");
1384         no_pragma_header = curl_slist_append(no_pragma_header, "Pragma:");
1385         no_range_header = curl_slist_append(no_range_header, "Range:");
1386
1387 #ifndef NO_CURL_EASY_DUPHANDLE
1388         curl_default = get_curl_handle();
1389 #endif
1390
1391         alt = xmalloc(sizeof(*alt));
1392         alt->base = url;
1393         alt->got_indices = 0;
1394         alt->packs = NULL;
1395         alt->next = NULL;
1396
1397         if (pull(commit_id))
1398                 rc = 1;
1399
1400         curl_slist_free_all(pragma_header);
1401         curl_slist_free_all(no_pragma_header);
1402         curl_slist_free_all(no_range_header);
1403 #ifndef NO_CURL_EASY_DUPHANDLE
1404         curl_easy_cleanup(curl_default);
1405 #endif
1406         slot = active_queue_head;
1407         while (slot != NULL) {
1408                 if (slot->in_use) {
1409                         if (get_verbosely) {
1410                                 curl_easy_getinfo(slot->curl,
1411                                                   CURLINFO_EFFECTIVE_URL,
1412                                                   &wait_url);
1413                                 fprintf(stderr, "Waiting for %s\n", wait_url);
1414                         }
1415                         run_active_slot(slot);
1416                 }
1417                 if (slot->curl != NULL)
1418                         curl_easy_cleanup(slot->curl);
1419                 slot = slot->next;
1420         }
1421 #ifdef USE_CURL_MULTI
1422         curl_multi_cleanup(curlm);
1423 #endif
1424         curl_global_cleanup();
1425         return rc;
1426 }