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