Merge branch 'master' of git://github.com/git-l10n/git-po
[git] / connect.c
1 #include "git-compat-util.h"
2 #include "cache.h"
3 #include "config.h"
4 #include "pkt-line.h"
5 #include "quote.h"
6 #include "refs.h"
7 #include "run-command.h"
8 #include "remote.h"
9 #include "connect.h"
10 #include "url.h"
11 #include "string-list.h"
12 #include "sha1-array.h"
13 #include "transport.h"
14 #include "strbuf.h"
15 #include "version.h"
16 #include "protocol.h"
17 #include "alias.h"
18
19 static char *server_capabilities_v1;
20 static struct argv_array server_capabilities_v2 = ARGV_ARRAY_INIT;
21 static const char *parse_feature_value(const char *, const char *, int *);
22
23 static int check_ref(const char *name, unsigned int flags)
24 {
25         if (!flags)
26                 return 1;
27
28         if (!skip_prefix(name, "refs/", &name))
29                 return 0;
30
31         /* REF_NORMAL means that we don't want the magic fake tag refs */
32         if ((flags & REF_NORMAL) && check_refname_format(name, 0))
33                 return 0;
34
35         /* REF_HEADS means that we want regular branch heads */
36         if ((flags & REF_HEADS) && starts_with(name, "heads/"))
37                 return 1;
38
39         /* REF_TAGS means that we want tags */
40         if ((flags & REF_TAGS) && starts_with(name, "tags/"))
41                 return 1;
42
43         /* All type bits clear means that we are ok with anything */
44         return !(flags & ~REF_NORMAL);
45 }
46
47 int check_ref_type(const struct ref *ref, int flags)
48 {
49         return check_ref(ref->name, flags);
50 }
51
52 static NORETURN void die_initial_contact(int unexpected)
53 {
54         /*
55          * A hang-up after seeing some response from the other end
56          * means that it is unexpected, as we know the other end is
57          * willing to talk to us.  A hang-up before seeing any
58          * response does not necessarily mean an ACL problem, though.
59          */
60         if (unexpected)
61                 die(_("The remote end hung up upon initial contact"));
62         else
63                 die(_("Could not read from remote repository.\n\n"
64                       "Please make sure you have the correct access rights\n"
65                       "and the repository exists."));
66 }
67
68 /* Checks if the server supports the capability 'c' */
69 int server_supports_v2(const char *c, int die_on_error)
70 {
71         int i;
72
73         for (i = 0; i < server_capabilities_v2.argc; i++) {
74                 const char *out;
75                 if (skip_prefix(server_capabilities_v2.argv[i], c, &out) &&
76                     (!*out || *out == '='))
77                         return 1;
78         }
79
80         if (die_on_error)
81                 die("server doesn't support '%s'", c);
82
83         return 0;
84 }
85
86 int server_supports_feature(const char *c, const char *feature,
87                             int die_on_error)
88 {
89         int i;
90
91         for (i = 0; i < server_capabilities_v2.argc; i++) {
92                 const char *out;
93                 if (skip_prefix(server_capabilities_v2.argv[i], c, &out) &&
94                     (!*out || *(out++) == '=')) {
95                         if (parse_feature_request(out, feature))
96                                 return 1;
97                         else
98                                 break;
99                 }
100         }
101
102         if (die_on_error)
103                 die("server doesn't support feature '%s'", feature);
104
105         return 0;
106 }
107
108 static void process_capabilities_v2(struct packet_reader *reader)
109 {
110         while (packet_reader_read(reader) == PACKET_READ_NORMAL)
111                 argv_array_push(&server_capabilities_v2, reader->line);
112
113         if (reader->status != PACKET_READ_FLUSH)
114                 die("expected flush after capabilities");
115 }
116
117 enum protocol_version discover_version(struct packet_reader *reader)
118 {
119         enum protocol_version version = protocol_unknown_version;
120
121         /*
122          * Peek the first line of the server's response to
123          * determine the protocol version the server is speaking.
124          */
125         switch (packet_reader_peek(reader)) {
126         case PACKET_READ_EOF:
127                 die_initial_contact(0);
128         case PACKET_READ_FLUSH:
129         case PACKET_READ_DELIM:
130                 version = protocol_v0;
131                 break;
132         case PACKET_READ_NORMAL:
133                 version = determine_protocol_version_client(reader->line);
134                 break;
135         }
136
137         switch (version) {
138         case protocol_v2:
139                 process_capabilities_v2(reader);
140                 break;
141         case protocol_v1:
142                 /* Read the peeked version line */
143                 packet_reader_read(reader);
144                 break;
145         case protocol_v0:
146                 break;
147         case protocol_unknown_version:
148                 BUG("unknown protocol version");
149         }
150
151         return version;
152 }
153
154 static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
155 {
156         char *sym, *target;
157         struct string_list_item *item;
158
159         if (!len)
160                 return; /* just "symref" */
161         /* e.g. "symref=HEAD:refs/heads/master" */
162         sym = xmemdupz(val, len);
163         target = strchr(sym, ':');
164         if (!target)
165                 /* just "symref=something" */
166                 goto reject;
167         *(target++) = '\0';
168         if (check_refname_format(sym, REFNAME_ALLOW_ONELEVEL) ||
169             check_refname_format(target, REFNAME_ALLOW_ONELEVEL))
170                 /* "symref=bogus:pair */
171                 goto reject;
172         item = string_list_append_nodup(symref, sym);
173         item->util = target;
174         return;
175 reject:
176         free(sym);
177         return;
178 }
179
180 static void annotate_refs_with_symref_info(struct ref *ref)
181 {
182         struct string_list symref = STRING_LIST_INIT_DUP;
183         const char *feature_list = server_capabilities_v1;
184
185         while (feature_list) {
186                 int len;
187                 const char *val;
188
189                 val = parse_feature_value(feature_list, "symref", &len);
190                 if (!val)
191                         break;
192                 parse_one_symref_info(&symref, val, len);
193                 feature_list = val + 1;
194         }
195         string_list_sort(&symref);
196
197         for (; ref; ref = ref->next) {
198                 struct string_list_item *item;
199                 item = string_list_lookup(&symref, ref->name);
200                 if (!item)
201                         continue;
202                 ref->symref = xstrdup((char *)item->util);
203         }
204         string_list_clear(&symref, 0);
205 }
206
207 static void process_capabilities(const char *line, int *len)
208 {
209         int nul_location = strlen(line);
210         if (nul_location == *len)
211                 return;
212         server_capabilities_v1 = xstrdup(line + nul_location + 1);
213         *len = nul_location;
214 }
215
216 static int process_dummy_ref(const char *line)
217 {
218         struct object_id oid;
219         const char *name;
220
221         if (parse_oid_hex(line, &oid, &name))
222                 return 0;
223         if (*name != ' ')
224                 return 0;
225         name++;
226
227         return !oidcmp(&null_oid, &oid) && !strcmp(name, "capabilities^{}");
228 }
229
230 static void check_no_capabilities(const char *line, int len)
231 {
232         if (strlen(line) != len)
233                 warning("Ignoring capabilities after first line '%s'",
234                         line + strlen(line));
235 }
236
237 static int process_ref(const char *line, int len, struct ref ***list,
238                        unsigned int flags, struct oid_array *extra_have)
239 {
240         struct object_id old_oid;
241         const char *name;
242
243         if (parse_oid_hex(line, &old_oid, &name))
244                 return 0;
245         if (*name != ' ')
246                 return 0;
247         name++;
248
249         if (extra_have && !strcmp(name, ".have")) {
250                 oid_array_append(extra_have, &old_oid);
251         } else if (!strcmp(name, "capabilities^{}")) {
252                 die("protocol error: unexpected capabilities^{}");
253         } else if (check_ref(name, flags)) {
254                 struct ref *ref = alloc_ref(name);
255                 oidcpy(&ref->old_oid, &old_oid);
256                 **list = ref;
257                 *list = &ref->next;
258         }
259         check_no_capabilities(line, len);
260         return 1;
261 }
262
263 static int process_shallow(const char *line, int len,
264                            struct oid_array *shallow_points)
265 {
266         const char *arg;
267         struct object_id old_oid;
268
269         if (!skip_prefix(line, "shallow ", &arg))
270                 return 0;
271
272         if (get_oid_hex(arg, &old_oid))
273                 die("protocol error: expected shallow sha-1, got '%s'", arg);
274         if (!shallow_points)
275                 die("repository on the other end cannot be shallow");
276         oid_array_append(shallow_points, &old_oid);
277         check_no_capabilities(line, len);
278         return 1;
279 }
280
281 enum get_remote_heads_state {
282         EXPECTING_FIRST_REF = 0,
283         EXPECTING_REF,
284         EXPECTING_SHALLOW,
285         EXPECTING_DONE,
286 };
287
288 /*
289  * Read all the refs from the other end
290  */
291 struct ref **get_remote_heads(struct packet_reader *reader,
292                               struct ref **list, unsigned int flags,
293                               struct oid_array *extra_have,
294                               struct oid_array *shallow_points)
295 {
296         struct ref **orig_list = list;
297         int len = 0;
298         enum get_remote_heads_state state = EXPECTING_FIRST_REF;
299         const char *arg;
300
301         *list = NULL;
302
303         while (state != EXPECTING_DONE) {
304                 switch (packet_reader_read(reader)) {
305                 case PACKET_READ_EOF:
306                         die_initial_contact(1);
307                 case PACKET_READ_NORMAL:
308                         len = reader->pktlen;
309                         if (len > 4 && skip_prefix(reader->line, "ERR ", &arg))
310                                 die("remote error: %s", arg);
311                         break;
312                 case PACKET_READ_FLUSH:
313                         state = EXPECTING_DONE;
314                         break;
315                 case PACKET_READ_DELIM:
316                         die("invalid packet");
317                 }
318
319                 switch (state) {
320                 case EXPECTING_FIRST_REF:
321                         process_capabilities(reader->line, &len);
322                         if (process_dummy_ref(reader->line)) {
323                                 state = EXPECTING_SHALLOW;
324                                 break;
325                         }
326                         state = EXPECTING_REF;
327                         /* fallthrough */
328                 case EXPECTING_REF:
329                         if (process_ref(reader->line, len, &list, flags, extra_have))
330                                 break;
331                         state = EXPECTING_SHALLOW;
332                         /* fallthrough */
333                 case EXPECTING_SHALLOW:
334                         if (process_shallow(reader->line, len, shallow_points))
335                                 break;
336                         die("protocol error: unexpected '%s'", reader->line);
337                 case EXPECTING_DONE:
338                         break;
339                 }
340         }
341
342         annotate_refs_with_symref_info(*orig_list);
343
344         return list;
345 }
346
347 /* Returns 1 when a valid ref has been added to `list`, 0 otherwise */
348 static int process_ref_v2(const char *line, struct ref ***list)
349 {
350         int ret = 1;
351         int i = 0;
352         struct object_id old_oid;
353         struct ref *ref;
354         struct string_list line_sections = STRING_LIST_INIT_DUP;
355         const char *end;
356
357         /*
358          * Ref lines have a number of fields which are space deliminated.  The
359          * first field is the OID of the ref.  The second field is the ref
360          * name.  Subsequent fields (symref-target and peeled) are optional and
361          * don't have a particular order.
362          */
363         if (string_list_split(&line_sections, line, ' ', -1) < 2) {
364                 ret = 0;
365                 goto out;
366         }
367
368         if (parse_oid_hex(line_sections.items[i++].string, &old_oid, &end) ||
369             *end) {
370                 ret = 0;
371                 goto out;
372         }
373
374         ref = alloc_ref(line_sections.items[i++].string);
375
376         oidcpy(&ref->old_oid, &old_oid);
377         **list = ref;
378         *list = &ref->next;
379
380         for (; i < line_sections.nr; i++) {
381                 const char *arg = line_sections.items[i].string;
382                 if (skip_prefix(arg, "symref-target:", &arg))
383                         ref->symref = xstrdup(arg);
384
385                 if (skip_prefix(arg, "peeled:", &arg)) {
386                         struct object_id peeled_oid;
387                         char *peeled_name;
388                         struct ref *peeled;
389                         if (parse_oid_hex(arg, &peeled_oid, &end) || *end) {
390                                 ret = 0;
391                                 goto out;
392                         }
393
394                         peeled_name = xstrfmt("%s^{}", ref->name);
395                         peeled = alloc_ref(peeled_name);
396
397                         oidcpy(&peeled->old_oid, &peeled_oid);
398                         **list = peeled;
399                         *list = &peeled->next;
400
401                         free(peeled_name);
402                 }
403         }
404
405 out:
406         string_list_clear(&line_sections, 0);
407         return ret;
408 }
409
410 struct ref **get_remote_refs(int fd_out, struct packet_reader *reader,
411                              struct ref **list, int for_push,
412                              const struct argv_array *ref_prefixes,
413                              const struct string_list *server_options)
414 {
415         int i;
416         *list = NULL;
417
418         if (server_supports_v2("ls-refs", 1))
419                 packet_write_fmt(fd_out, "command=ls-refs\n");
420
421         if (server_supports_v2("agent", 0))
422                 packet_write_fmt(fd_out, "agent=%s", git_user_agent_sanitized());
423
424         if (server_options && server_options->nr &&
425             server_supports_v2("server-option", 1))
426                 for (i = 0; i < server_options->nr; i++)
427                         packet_write_fmt(fd_out, "server-option=%s",
428                                          server_options->items[i].string);
429
430         packet_delim(fd_out);
431         /* When pushing we don't want to request the peeled tags */
432         if (!for_push)
433                 packet_write_fmt(fd_out, "peel\n");
434         packet_write_fmt(fd_out, "symrefs\n");
435         for (i = 0; ref_prefixes && i < ref_prefixes->argc; i++) {
436                 packet_write_fmt(fd_out, "ref-prefix %s\n",
437                                  ref_prefixes->argv[i]);
438         }
439         packet_flush(fd_out);
440
441         /* Process response from server */
442         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
443                 if (!process_ref_v2(reader->line, &list))
444                         die("invalid ls-refs response: %s", reader->line);
445         }
446
447         if (reader->status != PACKET_READ_FLUSH)
448                 die("expected flush after ref listing");
449
450         return list;
451 }
452
453 static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
454 {
455         int len;
456
457         if (!feature_list)
458                 return NULL;
459
460         len = strlen(feature);
461         while (*feature_list) {
462                 const char *found = strstr(feature_list, feature);
463                 if (!found)
464                         return NULL;
465                 if (feature_list == found || isspace(found[-1])) {
466                         const char *value = found + len;
467                         /* feature with no value (e.g., "thin-pack") */
468                         if (!*value || isspace(*value)) {
469                                 if (lenp)
470                                         *lenp = 0;
471                                 return value;
472                         }
473                         /* feature with a value (e.g., "agent=git/1.2.3") */
474                         else if (*value == '=') {
475                                 value++;
476                                 if (lenp)
477                                         *lenp = strcspn(value, " \t\n");
478                                 return value;
479                         }
480                         /*
481                          * otherwise we matched a substring of another feature;
482                          * keep looking
483                          */
484                 }
485                 feature_list = found + 1;
486         }
487         return NULL;
488 }
489
490 int parse_feature_request(const char *feature_list, const char *feature)
491 {
492         return !!parse_feature_value(feature_list, feature, NULL);
493 }
494
495 const char *server_feature_value(const char *feature, int *len)
496 {
497         return parse_feature_value(server_capabilities_v1, feature, len);
498 }
499
500 int server_supports(const char *feature)
501 {
502         return !!server_feature_value(feature, NULL);
503 }
504
505 enum protocol {
506         PROTO_LOCAL = 1,
507         PROTO_FILE,
508         PROTO_SSH,
509         PROTO_GIT
510 };
511
512 int url_is_local_not_ssh(const char *url)
513 {
514         const char *colon = strchr(url, ':');
515         const char *slash = strchr(url, '/');
516         return !colon || (slash && slash < colon) ||
517                 has_dos_drive_prefix(url);
518 }
519
520 static const char *prot_name(enum protocol protocol)
521 {
522         switch (protocol) {
523                 case PROTO_LOCAL:
524                 case PROTO_FILE:
525                         return "file";
526                 case PROTO_SSH:
527                         return "ssh";
528                 case PROTO_GIT:
529                         return "git";
530                 default:
531                         return "unknown protocol";
532         }
533 }
534
535 static enum protocol get_protocol(const char *name)
536 {
537         if (!strcmp(name, "ssh"))
538                 return PROTO_SSH;
539         if (!strcmp(name, "git"))
540                 return PROTO_GIT;
541         if (!strcmp(name, "git+ssh")) /* deprecated - do not use */
542                 return PROTO_SSH;
543         if (!strcmp(name, "ssh+git")) /* deprecated - do not use */
544                 return PROTO_SSH;
545         if (!strcmp(name, "file"))
546                 return PROTO_FILE;
547         die("I don't handle protocol '%s'", name);
548 }
549
550 static char *host_end(char **hoststart, int removebrackets)
551 {
552         char *host = *hoststart;
553         char *end;
554         char *start = strstr(host, "@[");
555         if (start)
556                 start++; /* Jump over '@' */
557         else
558                 start = host;
559         if (start[0] == '[') {
560                 end = strchr(start + 1, ']');
561                 if (end) {
562                         if (removebrackets) {
563                                 *end = 0;
564                                 memmove(start, start + 1, end - start);
565                                 end++;
566                         }
567                 } else
568                         end = host;
569         } else
570                 end = host;
571         return end;
572 }
573
574 #define STR_(s) # s
575 #define STR(s)  STR_(s)
576
577 static void get_host_and_port(char **host, const char **port)
578 {
579         char *colon, *end;
580         end = host_end(host, 1);
581         colon = strchr(end, ':');
582         if (colon) {
583                 long portnr = strtol(colon + 1, &end, 10);
584                 if (end != colon + 1 && *end == '\0' && 0 <= portnr && portnr < 65536) {
585                         *colon = 0;
586                         *port = colon + 1;
587                 } else if (!colon[1]) {
588                         *colon = 0;
589                 }
590         }
591 }
592
593 static void enable_keepalive(int sockfd)
594 {
595         int ka = 1;
596
597         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
598                 fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n",
599                         strerror(errno));
600 }
601
602 #ifndef NO_IPV6
603
604 static const char *ai_name(const struct addrinfo *ai)
605 {
606         static char addr[NI_MAXHOST];
607         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
608                         NI_NUMERICHOST) != 0)
609                 xsnprintf(addr, sizeof(addr), "(unknown)");
610
611         return addr;
612 }
613
614 /*
615  * Returns a connected socket() fd, or else die()s.
616  */
617 static int git_tcp_connect_sock(char *host, int flags)
618 {
619         struct strbuf error_message = STRBUF_INIT;
620         int sockfd = -1;
621         const char *port = STR(DEFAULT_GIT_PORT);
622         struct addrinfo hints, *ai0, *ai;
623         int gai;
624         int cnt = 0;
625
626         get_host_and_port(&host, &port);
627         if (!*port)
628                 port = "<none>";
629
630         memset(&hints, 0, sizeof(hints));
631         if (flags & CONNECT_IPV4)
632                 hints.ai_family = AF_INET;
633         else if (flags & CONNECT_IPV6)
634                 hints.ai_family = AF_INET6;
635         hints.ai_socktype = SOCK_STREAM;
636         hints.ai_protocol = IPPROTO_TCP;
637
638         if (flags & CONNECT_VERBOSE)
639                 fprintf(stderr, "Looking up %s ... ", host);
640
641         gai = getaddrinfo(host, port, &hints, &ai);
642         if (gai)
643                 die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
644
645         if (flags & CONNECT_VERBOSE)
646                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
647
648         for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
649                 sockfd = socket(ai->ai_family,
650                                 ai->ai_socktype, ai->ai_protocol);
651                 if ((sockfd < 0) ||
652                     (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
653                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
654                                     host, cnt, ai_name(ai), strerror(errno));
655                         if (0 <= sockfd)
656                                 close(sockfd);
657                         sockfd = -1;
658                         continue;
659                 }
660                 if (flags & CONNECT_VERBOSE)
661                         fprintf(stderr, "%s ", ai_name(ai));
662                 break;
663         }
664
665         freeaddrinfo(ai0);
666
667         if (sockfd < 0)
668                 die("unable to connect to %s:\n%s", host, error_message.buf);
669
670         enable_keepalive(sockfd);
671
672         if (flags & CONNECT_VERBOSE)
673                 fprintf(stderr, "done.\n");
674
675         strbuf_release(&error_message);
676
677         return sockfd;
678 }
679
680 #else /* NO_IPV6 */
681
682 /*
683  * Returns a connected socket() fd, or else die()s.
684  */
685 static int git_tcp_connect_sock(char *host, int flags)
686 {
687         struct strbuf error_message = STRBUF_INIT;
688         int sockfd = -1;
689         const char *port = STR(DEFAULT_GIT_PORT);
690         char *ep;
691         struct hostent *he;
692         struct sockaddr_in sa;
693         char **ap;
694         unsigned int nport;
695         int cnt;
696
697         get_host_and_port(&host, &port);
698
699         if (flags & CONNECT_VERBOSE)
700                 fprintf(stderr, "Looking up %s ... ", host);
701
702         he = gethostbyname(host);
703         if (!he)
704                 die("Unable to look up %s (%s)", host, hstrerror(h_errno));
705         nport = strtoul(port, &ep, 10);
706         if ( ep == port || *ep ) {
707                 /* Not numeric */
708                 struct servent *se = getservbyname(port,"tcp");
709                 if ( !se )
710                         die("Unknown port %s", port);
711                 nport = se->s_port;
712         }
713
714         if (flags & CONNECT_VERBOSE)
715                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
716
717         for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
718                 memset(&sa, 0, sizeof sa);
719                 sa.sin_family = he->h_addrtype;
720                 sa.sin_port = htons(nport);
721                 memcpy(&sa.sin_addr, *ap, he->h_length);
722
723                 sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
724                 if ((sockfd < 0) ||
725                     connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
726                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
727                                 host,
728                                 cnt,
729                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr),
730                                 strerror(errno));
731                         if (0 <= sockfd)
732                                 close(sockfd);
733                         sockfd = -1;
734                         continue;
735                 }
736                 if (flags & CONNECT_VERBOSE)
737                         fprintf(stderr, "%s ",
738                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr));
739                 break;
740         }
741
742         if (sockfd < 0)
743                 die("unable to connect to %s:\n%s", host, error_message.buf);
744
745         enable_keepalive(sockfd);
746
747         if (flags & CONNECT_VERBOSE)
748                 fprintf(stderr, "done.\n");
749
750         return sockfd;
751 }
752
753 #endif /* NO_IPV6 */
754
755
756 /*
757  * Dummy child_process returned by git_connect() if the transport protocol
758  * does not need fork(2).
759  */
760 static struct child_process no_fork = CHILD_PROCESS_INIT;
761
762 int git_connection_is_socket(struct child_process *conn)
763 {
764         return conn == &no_fork;
765 }
766
767 static struct child_process *git_tcp_connect(int fd[2], char *host, int flags)
768 {
769         int sockfd = git_tcp_connect_sock(host, flags);
770
771         fd[0] = sockfd;
772         fd[1] = dup(sockfd);
773
774         return &no_fork;
775 }
776
777
778 static char *git_proxy_command;
779
780 static int git_proxy_command_options(const char *var, const char *value,
781                 void *cb)
782 {
783         if (!strcmp(var, "core.gitproxy")) {
784                 const char *for_pos;
785                 int matchlen = -1;
786                 int hostlen;
787                 const char *rhost_name = cb;
788                 int rhost_len = strlen(rhost_name);
789
790                 if (git_proxy_command)
791                         return 0;
792                 if (!value)
793                         return config_error_nonbool(var);
794                 /* [core]
795                  * ;# matches www.kernel.org as well
796                  * gitproxy = netcatter-1 for kernel.org
797                  * gitproxy = netcatter-2 for sample.xz
798                  * gitproxy = netcatter-default
799                  */
800                 for_pos = strstr(value, " for ");
801                 if (!for_pos)
802                         /* matches everybody */
803                         matchlen = strlen(value);
804                 else {
805                         hostlen = strlen(for_pos + 5);
806                         if (rhost_len < hostlen)
807                                 matchlen = -1;
808                         else if (!strncmp(for_pos + 5,
809                                           rhost_name + rhost_len - hostlen,
810                                           hostlen) &&
811                                  ((rhost_len == hostlen) ||
812                                   rhost_name[rhost_len - hostlen -1] == '.'))
813                                 matchlen = for_pos - value;
814                         else
815                                 matchlen = -1;
816                 }
817                 if (0 <= matchlen) {
818                         /* core.gitproxy = none for kernel.org */
819                         if (matchlen == 4 &&
820                             !memcmp(value, "none", 4))
821                                 matchlen = 0;
822                         git_proxy_command = xmemdupz(value, matchlen);
823                 }
824                 return 0;
825         }
826
827         return git_default_config(var, value, cb);
828 }
829
830 static int git_use_proxy(const char *host)
831 {
832         git_proxy_command = getenv("GIT_PROXY_COMMAND");
833         git_config(git_proxy_command_options, (void*)host);
834         return (git_proxy_command && *git_proxy_command);
835 }
836
837 static struct child_process *git_proxy_connect(int fd[2], char *host)
838 {
839         const char *port = STR(DEFAULT_GIT_PORT);
840         struct child_process *proxy;
841
842         get_host_and_port(&host, &port);
843
844         if (looks_like_command_line_option(host))
845                 die("strange hostname '%s' blocked", host);
846         if (looks_like_command_line_option(port))
847                 die("strange port '%s' blocked", port);
848
849         proxy = xmalloc(sizeof(*proxy));
850         child_process_init(proxy);
851         argv_array_push(&proxy->args, git_proxy_command);
852         argv_array_push(&proxy->args, host);
853         argv_array_push(&proxy->args, port);
854         proxy->in = -1;
855         proxy->out = -1;
856         if (start_command(proxy))
857                 die("cannot start proxy %s", git_proxy_command);
858         fd[0] = proxy->out; /* read from proxy stdout */
859         fd[1] = proxy->in;  /* write to proxy stdin */
860         return proxy;
861 }
862
863 static char *get_port(char *host)
864 {
865         char *end;
866         char *p = strchr(host, ':');
867
868         if (p) {
869                 long port = strtol(p + 1, &end, 10);
870                 if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
871                         *p = '\0';
872                         return p+1;
873                 }
874         }
875
876         return NULL;
877 }
878
879 /*
880  * Extract protocol and relevant parts from the specified connection URL.
881  * The caller must free() the returned strings.
882  */
883 static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
884                                        char **ret_path)
885 {
886         char *url;
887         char *host, *path;
888         char *end;
889         int separator = '/';
890         enum protocol protocol = PROTO_LOCAL;
891
892         if (is_url(url_orig))
893                 url = url_decode(url_orig);
894         else
895                 url = xstrdup(url_orig);
896
897         host = strstr(url, "://");
898         if (host) {
899                 *host = '\0';
900                 protocol = get_protocol(url);
901                 host += 3;
902         } else {
903                 host = url;
904                 if (!url_is_local_not_ssh(url)) {
905                         protocol = PROTO_SSH;
906                         separator = ':';
907                 }
908         }
909
910         /*
911          * Don't do destructive transforms as protocol code does
912          * '[]' unwrapping in get_host_and_port()
913          */
914         end = host_end(&host, 0);
915
916         if (protocol == PROTO_LOCAL)
917                 path = end;
918         else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
919                 path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
920         else
921                 path = strchr(end, separator);
922
923         if (!path || !*path)
924                 die("No path specified. See 'man git-pull' for valid url syntax");
925
926         /*
927          * null-terminate hostname and point path to ~ for URL's like this:
928          *    ssh://host.xz/~user/repo
929          */
930
931         end = path; /* Need to \0 terminate host here */
932         if (separator == ':')
933                 path++; /* path starts after ':' */
934         if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
935                 if (path[1] == '~')
936                         path++;
937         }
938
939         path = xstrdup(path);
940         *end = '\0';
941
942         *ret_host = xstrdup(host);
943         *ret_path = path;
944         free(url);
945         return protocol;
946 }
947
948 static const char *get_ssh_command(void)
949 {
950         const char *ssh;
951
952         if ((ssh = getenv("GIT_SSH_COMMAND")))
953                 return ssh;
954
955         if (!git_config_get_string_const("core.sshcommand", &ssh))
956                 return ssh;
957
958         return NULL;
959 }
960
961 enum ssh_variant {
962         VARIANT_AUTO,
963         VARIANT_SIMPLE,
964         VARIANT_SSH,
965         VARIANT_PLINK,
966         VARIANT_PUTTY,
967         VARIANT_TORTOISEPLINK,
968 };
969
970 static void override_ssh_variant(enum ssh_variant *ssh_variant)
971 {
972         const char *variant = getenv("GIT_SSH_VARIANT");
973
974         if (!variant && git_config_get_string_const("ssh.variant", &variant))
975                 return;
976
977         if (!strcmp(variant, "auto"))
978                 *ssh_variant = VARIANT_AUTO;
979         else if (!strcmp(variant, "plink"))
980                 *ssh_variant = VARIANT_PLINK;
981         else if (!strcmp(variant, "putty"))
982                 *ssh_variant = VARIANT_PUTTY;
983         else if (!strcmp(variant, "tortoiseplink"))
984                 *ssh_variant = VARIANT_TORTOISEPLINK;
985         else if (!strcmp(variant, "simple"))
986                 *ssh_variant = VARIANT_SIMPLE;
987         else
988                 *ssh_variant = VARIANT_SSH;
989 }
990
991 static enum ssh_variant determine_ssh_variant(const char *ssh_command,
992                                               int is_cmdline)
993 {
994         enum ssh_variant ssh_variant = VARIANT_AUTO;
995         const char *variant;
996         char *p = NULL;
997
998         override_ssh_variant(&ssh_variant);
999
1000         if (ssh_variant != VARIANT_AUTO)
1001                 return ssh_variant;
1002
1003         if (!is_cmdline) {
1004                 p = xstrdup(ssh_command);
1005                 variant = basename(p);
1006         } else {
1007                 const char **ssh_argv;
1008
1009                 p = xstrdup(ssh_command);
1010                 if (split_cmdline(p, &ssh_argv) > 0) {
1011                         variant = basename((char *)ssh_argv[0]);
1012                         /*
1013                          * At this point, variant points into the buffer
1014                          * referenced by p, hence we do not need ssh_argv
1015                          * any longer.
1016                          */
1017                         free(ssh_argv);
1018                 } else {
1019                         free(p);
1020                         return ssh_variant;
1021                 }
1022         }
1023
1024         if (!strcasecmp(variant, "ssh") ||
1025             !strcasecmp(variant, "ssh.exe"))
1026                 ssh_variant = VARIANT_SSH;
1027         else if (!strcasecmp(variant, "plink") ||
1028                  !strcasecmp(variant, "plink.exe"))
1029                 ssh_variant = VARIANT_PLINK;
1030         else if (!strcasecmp(variant, "tortoiseplink") ||
1031                  !strcasecmp(variant, "tortoiseplink.exe"))
1032                 ssh_variant = VARIANT_TORTOISEPLINK;
1033
1034         free(p);
1035         return ssh_variant;
1036 }
1037
1038 /*
1039  * Open a connection using Git's native protocol.
1040  *
1041  * The caller is responsible for freeing hostandport, but this function may
1042  * modify it (for example, to truncate it to remove the port part).
1043  */
1044 static struct child_process *git_connect_git(int fd[2], char *hostandport,
1045                                              const char *path, const char *prog,
1046                                              enum protocol_version version,
1047                                              int flags)
1048 {
1049         struct child_process *conn;
1050         struct strbuf request = STRBUF_INIT;
1051         /*
1052          * Set up virtual host information based on where we will
1053          * connect, unless the user has overridden us in
1054          * the environment.
1055          */
1056         char *target_host = getenv("GIT_OVERRIDE_VIRTUAL_HOST");
1057         if (target_host)
1058                 target_host = xstrdup(target_host);
1059         else
1060                 target_host = xstrdup(hostandport);
1061
1062         transport_check_allowed("git");
1063
1064         /*
1065          * These underlying connection commands die() if they
1066          * cannot connect.
1067          */
1068         if (git_use_proxy(hostandport))
1069                 conn = git_proxy_connect(fd, hostandport);
1070         else
1071                 conn = git_tcp_connect(fd, hostandport, flags);
1072         /*
1073          * Separate original protocol components prog and path
1074          * from extended host header with a NUL byte.
1075          *
1076          * Note: Do not add any other headers here!  Doing so
1077          * will cause older git-daemon servers to crash.
1078          */
1079         strbuf_addf(&request,
1080                     "%s %s%chost=%s%c",
1081                     prog, path, 0,
1082                     target_host, 0);
1083
1084         /* If using a new version put that stuff here after a second null byte */
1085         if (version > 0) {
1086                 strbuf_addch(&request, '\0');
1087                 strbuf_addf(&request, "version=%d%c",
1088                             version, '\0');
1089         }
1090
1091         packet_write(fd[1], request.buf, request.len);
1092
1093         free(target_host);
1094         strbuf_release(&request);
1095         return conn;
1096 }
1097
1098 /*
1099  * Append the appropriate environment variables to `env` and options to
1100  * `args` for running ssh in Git's SSH-tunneled transport.
1101  */
1102 static void push_ssh_options(struct argv_array *args, struct argv_array *env,
1103                              enum ssh_variant variant, const char *port,
1104                              enum protocol_version version, int flags)
1105 {
1106         if (variant == VARIANT_SSH &&
1107             version > 0) {
1108                 argv_array_push(args, "-o");
1109                 argv_array_push(args, "SendEnv=" GIT_PROTOCOL_ENVIRONMENT);
1110                 argv_array_pushf(env, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
1111                                  version);
1112         }
1113
1114         if (flags & CONNECT_IPV4) {
1115                 switch (variant) {
1116                 case VARIANT_AUTO:
1117                         BUG("VARIANT_AUTO passed to push_ssh_options");
1118                 case VARIANT_SIMPLE:
1119                         die("ssh variant 'simple' does not support -4");
1120                 case VARIANT_SSH:
1121                 case VARIANT_PLINK:
1122                 case VARIANT_PUTTY:
1123                 case VARIANT_TORTOISEPLINK:
1124                         argv_array_push(args, "-4");
1125                 }
1126         } else if (flags & CONNECT_IPV6) {
1127                 switch (variant) {
1128                 case VARIANT_AUTO:
1129                         BUG("VARIANT_AUTO passed to push_ssh_options");
1130                 case VARIANT_SIMPLE:
1131                         die("ssh variant 'simple' does not support -6");
1132                 case VARIANT_SSH:
1133                 case VARIANT_PLINK:
1134                 case VARIANT_PUTTY:
1135                 case VARIANT_TORTOISEPLINK:
1136                         argv_array_push(args, "-6");
1137                 }
1138         }
1139
1140         if (variant == VARIANT_TORTOISEPLINK)
1141                 argv_array_push(args, "-batch");
1142
1143         if (port) {
1144                 switch (variant) {
1145                 case VARIANT_AUTO:
1146                         BUG("VARIANT_AUTO passed to push_ssh_options");
1147                 case VARIANT_SIMPLE:
1148                         die("ssh variant 'simple' does not support setting port");
1149                 case VARIANT_SSH:
1150                         argv_array_push(args, "-p");
1151                         break;
1152                 case VARIANT_PLINK:
1153                 case VARIANT_PUTTY:
1154                 case VARIANT_TORTOISEPLINK:
1155                         argv_array_push(args, "-P");
1156                 }
1157
1158                 argv_array_push(args, port);
1159         }
1160 }
1161
1162 /* Prepare a child_process for use by Git's SSH-tunneled transport. */
1163 static void fill_ssh_args(struct child_process *conn, const char *ssh_host,
1164                           const char *port, enum protocol_version version,
1165                           int flags)
1166 {
1167         const char *ssh;
1168         enum ssh_variant variant;
1169
1170         if (looks_like_command_line_option(ssh_host))
1171                 die("strange hostname '%s' blocked", ssh_host);
1172
1173         ssh = get_ssh_command();
1174         if (ssh) {
1175                 variant = determine_ssh_variant(ssh, 1);
1176         } else {
1177                 /*
1178                  * GIT_SSH is the no-shell version of
1179                  * GIT_SSH_COMMAND (and must remain so for
1180                  * historical compatibility).
1181                  */
1182                 conn->use_shell = 0;
1183
1184                 ssh = getenv("GIT_SSH");
1185                 if (!ssh)
1186                         ssh = "ssh";
1187                 variant = determine_ssh_variant(ssh, 0);
1188         }
1189
1190         if (variant == VARIANT_AUTO) {
1191                 struct child_process detect = CHILD_PROCESS_INIT;
1192
1193                 detect.use_shell = conn->use_shell;
1194                 detect.no_stdin = detect.no_stdout = detect.no_stderr = 1;
1195
1196                 argv_array_push(&detect.args, ssh);
1197                 argv_array_push(&detect.args, "-G");
1198                 push_ssh_options(&detect.args, &detect.env_array,
1199                                  VARIANT_SSH, port, version, flags);
1200                 argv_array_push(&detect.args, ssh_host);
1201
1202                 variant = run_command(&detect) ? VARIANT_SIMPLE : VARIANT_SSH;
1203         }
1204
1205         argv_array_push(&conn->args, ssh);
1206         push_ssh_options(&conn->args, &conn->env_array, variant, port, version, flags);
1207         argv_array_push(&conn->args, ssh_host);
1208 }
1209
1210 /*
1211  * This returns the dummy child_process `no_fork` if the transport protocol
1212  * does not need fork(2), or a struct child_process object if it does.  Once
1213  * done, finish the connection with finish_connect() with the value returned
1214  * from this function (it is safe to call finish_connect() with NULL to
1215  * support the former case).
1216  *
1217  * If it returns, the connect is successful; it just dies on errors (this
1218  * will hopefully be changed in a libification effort, to return NULL when
1219  * the connection failed).
1220  */
1221 struct child_process *git_connect(int fd[2], const char *url,
1222                                   const char *prog, int flags)
1223 {
1224         char *hostandport, *path;
1225         struct child_process *conn;
1226         enum protocol protocol;
1227         enum protocol_version version = get_protocol_version_config();
1228
1229         /*
1230          * NEEDSWORK: If we are trying to use protocol v2 and we are planning
1231          * to perform a push, then fallback to v0 since the client doesn't know
1232          * how to push yet using v2.
1233          */
1234         if (version == protocol_v2 && !strcmp("git-receive-pack", prog))
1235                 version = protocol_v0;
1236
1237         /* Without this we cannot rely on waitpid() to tell
1238          * what happened to our children.
1239          */
1240         signal(SIGCHLD, SIG_DFL);
1241
1242         protocol = parse_connect_url(url, &hostandport, &path);
1243         if ((flags & CONNECT_DIAG_URL) && (protocol != PROTO_SSH)) {
1244                 printf("Diag: url=%s\n", url ? url : "NULL");
1245                 printf("Diag: protocol=%s\n", prot_name(protocol));
1246                 printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
1247                 printf("Diag: path=%s\n", path ? path : "NULL");
1248                 conn = NULL;
1249         } else if (protocol == PROTO_GIT) {
1250                 conn = git_connect_git(fd, hostandport, path, prog, version, flags);
1251         } else {
1252                 struct strbuf cmd = STRBUF_INIT;
1253                 const char *const *var;
1254
1255                 conn = xmalloc(sizeof(*conn));
1256                 child_process_init(conn);
1257
1258                 if (looks_like_command_line_option(path))
1259                         die("strange pathname '%s' blocked", path);
1260
1261                 strbuf_addstr(&cmd, prog);
1262                 strbuf_addch(&cmd, ' ');
1263                 sq_quote_buf(&cmd, path);
1264
1265                 /* remove repo-local variables from the environment */
1266                 for (var = local_repo_env; *var; var++)
1267                         argv_array_push(&conn->env_array, *var);
1268
1269                 conn->use_shell = 1;
1270                 conn->in = conn->out = -1;
1271                 if (protocol == PROTO_SSH) {
1272                         char *ssh_host = hostandport;
1273                         const char *port = NULL;
1274                         transport_check_allowed("ssh");
1275                         get_host_and_port(&ssh_host, &port);
1276
1277                         if (!port)
1278                                 port = get_port(ssh_host);
1279
1280                         if (flags & CONNECT_DIAG_URL) {
1281                                 printf("Diag: url=%s\n", url ? url : "NULL");
1282                                 printf("Diag: protocol=%s\n", prot_name(protocol));
1283                                 printf("Diag: userandhost=%s\n", ssh_host ? ssh_host : "NULL");
1284                                 printf("Diag: port=%s\n", port ? port : "NONE");
1285                                 printf("Diag: path=%s\n", path ? path : "NULL");
1286
1287                                 free(hostandport);
1288                                 free(path);
1289                                 free(conn);
1290                                 strbuf_release(&cmd);
1291                                 return NULL;
1292                         }
1293                         fill_ssh_args(conn, ssh_host, port, version, flags);
1294                 } else {
1295                         transport_check_allowed("file");
1296                         if (version > 0) {
1297                                 argv_array_pushf(&conn->env_array, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
1298                                                  version);
1299                         }
1300                 }
1301                 argv_array_push(&conn->args, cmd.buf);
1302
1303                 if (start_command(conn))
1304                         die("unable to fork");
1305
1306                 fd[0] = conn->out; /* read from child's stdout */
1307                 fd[1] = conn->in;  /* write to child's stdin */
1308                 strbuf_release(&cmd);
1309         }
1310         free(hostandport);
1311         free(path);
1312         return conn;
1313 }
1314
1315 int finish_connect(struct child_process *conn)
1316 {
1317         int code;
1318         if (!conn || git_connection_is_socket(conn))
1319                 return 0;
1320
1321         code = finish_command(conn);
1322         free(conn);
1323         return code;
1324 }