Imported Upstream version 2.12.0
[platform/upstream/git.git] / connect.c
1 #include "git-compat-util.h"
2 #include "cache.h"
3 #include "pkt-line.h"
4 #include "quote.h"
5 #include "refs.h"
6 #include "run-command.h"
7 #include "remote.h"
8 #include "connect.h"
9 #include "url.h"
10 #include "string-list.h"
11 #include "sha1-array.h"
12 #include "transport.h"
13
14 static char *server_capabilities;
15 static const char *parse_feature_value(const char *, const char *, int *);
16
17 static int check_ref(const char *name, unsigned int flags)
18 {
19         if (!flags)
20                 return 1;
21
22         if (!skip_prefix(name, "refs/", &name))
23                 return 0;
24
25         /* REF_NORMAL means that we don't want the magic fake tag refs */
26         if ((flags & REF_NORMAL) && check_refname_format(name, 0))
27                 return 0;
28
29         /* REF_HEADS means that we want regular branch heads */
30         if ((flags & REF_HEADS) && starts_with(name, "heads/"))
31                 return 1;
32
33         /* REF_TAGS means that we want tags */
34         if ((flags & REF_TAGS) && starts_with(name, "tags/"))
35                 return 1;
36
37         /* All type bits clear means that we are ok with anything */
38         return !(flags & ~REF_NORMAL);
39 }
40
41 int check_ref_type(const struct ref *ref, int flags)
42 {
43         return check_ref(ref->name, flags);
44 }
45
46 static void die_initial_contact(int unexpected)
47 {
48         if (unexpected)
49                 die(_("The remote end hung up upon initial contact"));
50         else
51                 die(_("Could not read from remote repository.\n\n"
52                       "Please make sure you have the correct access rights\n"
53                       "and the repository exists."));
54 }
55
56 static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
57 {
58         char *sym, *target;
59         struct string_list_item *item;
60
61         if (!len)
62                 return; /* just "symref" */
63         /* e.g. "symref=HEAD:refs/heads/master" */
64         sym = xmemdupz(val, len);
65         target = strchr(sym, ':');
66         if (!target)
67                 /* just "symref=something" */
68                 goto reject;
69         *(target++) = '\0';
70         if (check_refname_format(sym, REFNAME_ALLOW_ONELEVEL) ||
71             check_refname_format(target, REFNAME_ALLOW_ONELEVEL))
72                 /* "symref=bogus:pair */
73                 goto reject;
74         item = string_list_append(symref, sym);
75         item->util = target;
76         return;
77 reject:
78         free(sym);
79         return;
80 }
81
82 static void annotate_refs_with_symref_info(struct ref *ref)
83 {
84         struct string_list symref = STRING_LIST_INIT_DUP;
85         const char *feature_list = server_capabilities;
86
87         while (feature_list) {
88                 int len;
89                 const char *val;
90
91                 val = parse_feature_value(feature_list, "symref", &len);
92                 if (!val)
93                         break;
94                 parse_one_symref_info(&symref, val, len);
95                 feature_list = val + 1;
96         }
97         string_list_sort(&symref);
98
99         for (; ref; ref = ref->next) {
100                 struct string_list_item *item;
101                 item = string_list_lookup(&symref, ref->name);
102                 if (!item)
103                         continue;
104                 ref->symref = xstrdup((char *)item->util);
105         }
106         string_list_clear(&symref, 0);
107 }
108
109 /*
110  * Read all the refs from the other end
111  */
112 struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
113                               struct ref **list, unsigned int flags,
114                               struct sha1_array *extra_have,
115                               struct sha1_array *shallow_points)
116 {
117         struct ref **orig_list = list;
118
119         /*
120          * A hang-up after seeing some response from the other end
121          * means that it is unexpected, as we know the other end is
122          * willing to talk to us.  A hang-up before seeing any
123          * response does not necessarily mean an ACL problem, though.
124          */
125         int saw_response;
126         int got_dummy_ref_with_capabilities_declaration = 0;
127
128         *list = NULL;
129         for (saw_response = 0; ; saw_response = 1) {
130                 struct ref *ref;
131                 struct object_id old_oid;
132                 char *name;
133                 int len, name_len;
134                 char *buffer = packet_buffer;
135                 const char *arg;
136
137                 len = packet_read(in, &src_buf, &src_len,
138                                   packet_buffer, sizeof(packet_buffer),
139                                   PACKET_READ_GENTLE_ON_EOF |
140                                   PACKET_READ_CHOMP_NEWLINE);
141                 if (len < 0)
142                         die_initial_contact(saw_response);
143
144                 if (!len)
145                         break;
146
147                 if (len > 4 && skip_prefix(buffer, "ERR ", &arg))
148                         die("remote error: %s", arg);
149
150                 if (len == GIT_SHA1_HEXSZ + strlen("shallow ") &&
151                         skip_prefix(buffer, "shallow ", &arg)) {
152                         if (get_oid_hex(arg, &old_oid))
153                                 die("protocol error: expected shallow sha-1, got '%s'", arg);
154                         if (!shallow_points)
155                                 die("repository on the other end cannot be shallow");
156                         sha1_array_append(shallow_points, old_oid.hash);
157                         continue;
158                 }
159
160                 if (len < GIT_SHA1_HEXSZ + 2 || get_oid_hex(buffer, &old_oid) ||
161                         buffer[GIT_SHA1_HEXSZ] != ' ')
162                         die("protocol error: expected sha/ref, got '%s'", buffer);
163                 name = buffer + GIT_SHA1_HEXSZ + 1;
164
165                 name_len = strlen(name);
166                 if (len != name_len + GIT_SHA1_HEXSZ + 1) {
167                         free(server_capabilities);
168                         server_capabilities = xstrdup(name + name_len + 1);
169                 }
170
171                 if (extra_have && !strcmp(name, ".have")) {
172                         sha1_array_append(extra_have, old_oid.hash);
173                         continue;
174                 }
175
176                 if (!strcmp(name, "capabilities^{}")) {
177                         if (saw_response)
178                                 die("protocol error: unexpected capabilities^{}");
179                         if (got_dummy_ref_with_capabilities_declaration)
180                                 die("protocol error: multiple capabilities^{}");
181                         got_dummy_ref_with_capabilities_declaration = 1;
182                         continue;
183                 }
184
185                 if (!check_ref(name, flags))
186                         continue;
187
188                 if (got_dummy_ref_with_capabilities_declaration)
189                         die("protocol error: unexpected ref after capabilities^{}");
190
191                 ref = alloc_ref(buffer + GIT_SHA1_HEXSZ + 1);
192                 oidcpy(&ref->old_oid, &old_oid);
193                 *list = ref;
194                 list = &ref->next;
195         }
196
197         annotate_refs_with_symref_info(*orig_list);
198
199         return list;
200 }
201
202 static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
203 {
204         int len;
205
206         if (!feature_list)
207                 return NULL;
208
209         len = strlen(feature);
210         while (*feature_list) {
211                 const char *found = strstr(feature_list, feature);
212                 if (!found)
213                         return NULL;
214                 if (feature_list == found || isspace(found[-1])) {
215                         const char *value = found + len;
216                         /* feature with no value (e.g., "thin-pack") */
217                         if (!*value || isspace(*value)) {
218                                 if (lenp)
219                                         *lenp = 0;
220                                 return value;
221                         }
222                         /* feature with a value (e.g., "agent=git/1.2.3") */
223                         else if (*value == '=') {
224                                 value++;
225                                 if (lenp)
226                                         *lenp = strcspn(value, " \t\n");
227                                 return value;
228                         }
229                         /*
230                          * otherwise we matched a substring of another feature;
231                          * keep looking
232                          */
233                 }
234                 feature_list = found + 1;
235         }
236         return NULL;
237 }
238
239 int parse_feature_request(const char *feature_list, const char *feature)
240 {
241         return !!parse_feature_value(feature_list, feature, NULL);
242 }
243
244 const char *server_feature_value(const char *feature, int *len)
245 {
246         return parse_feature_value(server_capabilities, feature, len);
247 }
248
249 int server_supports(const char *feature)
250 {
251         return !!server_feature_value(feature, NULL);
252 }
253
254 enum protocol {
255         PROTO_LOCAL = 1,
256         PROTO_FILE,
257         PROTO_SSH,
258         PROTO_GIT
259 };
260
261 int url_is_local_not_ssh(const char *url)
262 {
263         const char *colon = strchr(url, ':');
264         const char *slash = strchr(url, '/');
265         return !colon || (slash && slash < colon) ||
266                 has_dos_drive_prefix(url);
267 }
268
269 static const char *prot_name(enum protocol protocol)
270 {
271         switch (protocol) {
272                 case PROTO_LOCAL:
273                 case PROTO_FILE:
274                         return "file";
275                 case PROTO_SSH:
276                         return "ssh";
277                 case PROTO_GIT:
278                         return "git";
279                 default:
280                         return "unknown protocol";
281         }
282 }
283
284 static enum protocol get_protocol(const char *name)
285 {
286         if (!strcmp(name, "ssh"))
287                 return PROTO_SSH;
288         if (!strcmp(name, "git"))
289                 return PROTO_GIT;
290         if (!strcmp(name, "git+ssh")) /* deprecated - do not use */
291                 return PROTO_SSH;
292         if (!strcmp(name, "ssh+git")) /* deprecated - do not use */
293                 return PROTO_SSH;
294         if (!strcmp(name, "file"))
295                 return PROTO_FILE;
296         die("I don't handle protocol '%s'", name);
297 }
298
299 static char *host_end(char **hoststart, int removebrackets)
300 {
301         char *host = *hoststart;
302         char *end;
303         char *start = strstr(host, "@[");
304         if (start)
305                 start++; /* Jump over '@' */
306         else
307                 start = host;
308         if (start[0] == '[') {
309                 end = strchr(start + 1, ']');
310                 if (end) {
311                         if (removebrackets) {
312                                 *end = 0;
313                                 memmove(start, start + 1, end - start);
314                                 end++;
315                         }
316                 } else
317                         end = host;
318         } else
319                 end = host;
320         return end;
321 }
322
323 #define STR_(s) # s
324 #define STR(s)  STR_(s)
325
326 static void get_host_and_port(char **host, const char **port)
327 {
328         char *colon, *end;
329         end = host_end(host, 1);
330         colon = strchr(end, ':');
331         if (colon) {
332                 long portnr = strtol(colon + 1, &end, 10);
333                 if (end != colon + 1 && *end == '\0' && 0 <= portnr && portnr < 65536) {
334                         *colon = 0;
335                         *port = colon + 1;
336                 } else if (!colon[1]) {
337                         *colon = 0;
338                 }
339         }
340 }
341
342 static void enable_keepalive(int sockfd)
343 {
344         int ka = 1;
345
346         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
347                 fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n",
348                         strerror(errno));
349 }
350
351 #ifndef NO_IPV6
352
353 static const char *ai_name(const struct addrinfo *ai)
354 {
355         static char addr[NI_MAXHOST];
356         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
357                         NI_NUMERICHOST) != 0)
358                 xsnprintf(addr, sizeof(addr), "(unknown)");
359
360         return addr;
361 }
362
363 /*
364  * Returns a connected socket() fd, or else die()s.
365  */
366 static int git_tcp_connect_sock(char *host, int flags)
367 {
368         struct strbuf error_message = STRBUF_INIT;
369         int sockfd = -1;
370         const char *port = STR(DEFAULT_GIT_PORT);
371         struct addrinfo hints, *ai0, *ai;
372         int gai;
373         int cnt = 0;
374
375         get_host_and_port(&host, &port);
376         if (!*port)
377                 port = "<none>";
378
379         memset(&hints, 0, sizeof(hints));
380         if (flags & CONNECT_IPV4)
381                 hints.ai_family = AF_INET;
382         else if (flags & CONNECT_IPV6)
383                 hints.ai_family = AF_INET6;
384         hints.ai_socktype = SOCK_STREAM;
385         hints.ai_protocol = IPPROTO_TCP;
386
387         if (flags & CONNECT_VERBOSE)
388                 fprintf(stderr, "Looking up %s ... ", host);
389
390         gai = getaddrinfo(host, port, &hints, &ai);
391         if (gai)
392                 die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
393
394         if (flags & CONNECT_VERBOSE)
395                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
396
397         for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
398                 sockfd = socket(ai->ai_family,
399                                 ai->ai_socktype, ai->ai_protocol);
400                 if ((sockfd < 0) ||
401                     (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
402                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
403                                     host, cnt, ai_name(ai), strerror(errno));
404                         if (0 <= sockfd)
405                                 close(sockfd);
406                         sockfd = -1;
407                         continue;
408                 }
409                 if (flags & CONNECT_VERBOSE)
410                         fprintf(stderr, "%s ", ai_name(ai));
411                 break;
412         }
413
414         freeaddrinfo(ai0);
415
416         if (sockfd < 0)
417                 die("unable to connect to %s:\n%s", host, error_message.buf);
418
419         enable_keepalive(sockfd);
420
421         if (flags & CONNECT_VERBOSE)
422                 fprintf(stderr, "done.\n");
423
424         strbuf_release(&error_message);
425
426         return sockfd;
427 }
428
429 #else /* NO_IPV6 */
430
431 /*
432  * Returns a connected socket() fd, or else die()s.
433  */
434 static int git_tcp_connect_sock(char *host, int flags)
435 {
436         struct strbuf error_message = STRBUF_INIT;
437         int sockfd = -1;
438         const char *port = STR(DEFAULT_GIT_PORT);
439         char *ep;
440         struct hostent *he;
441         struct sockaddr_in sa;
442         char **ap;
443         unsigned int nport;
444         int cnt;
445
446         get_host_and_port(&host, &port);
447
448         if (flags & CONNECT_VERBOSE)
449                 fprintf(stderr, "Looking up %s ... ", host);
450
451         he = gethostbyname(host);
452         if (!he)
453                 die("Unable to look up %s (%s)", host, hstrerror(h_errno));
454         nport = strtoul(port, &ep, 10);
455         if ( ep == port || *ep ) {
456                 /* Not numeric */
457                 struct servent *se = getservbyname(port,"tcp");
458                 if ( !se )
459                         die("Unknown port %s", port);
460                 nport = se->s_port;
461         }
462
463         if (flags & CONNECT_VERBOSE)
464                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
465
466         for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
467                 memset(&sa, 0, sizeof sa);
468                 sa.sin_family = he->h_addrtype;
469                 sa.sin_port = htons(nport);
470                 memcpy(&sa.sin_addr, *ap, he->h_length);
471
472                 sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
473                 if ((sockfd < 0) ||
474                     connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
475                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
476                                 host,
477                                 cnt,
478                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr),
479                                 strerror(errno));
480                         if (0 <= sockfd)
481                                 close(sockfd);
482                         sockfd = -1;
483                         continue;
484                 }
485                 if (flags & CONNECT_VERBOSE)
486                         fprintf(stderr, "%s ",
487                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr));
488                 break;
489         }
490
491         if (sockfd < 0)
492                 die("unable to connect to %s:\n%s", host, error_message.buf);
493
494         enable_keepalive(sockfd);
495
496         if (flags & CONNECT_VERBOSE)
497                 fprintf(stderr, "done.\n");
498
499         return sockfd;
500 }
501
502 #endif /* NO_IPV6 */
503
504
505 static void git_tcp_connect(int fd[2], char *host, int flags)
506 {
507         int sockfd = git_tcp_connect_sock(host, flags);
508
509         fd[0] = sockfd;
510         fd[1] = dup(sockfd);
511 }
512
513
514 static char *git_proxy_command;
515
516 static int git_proxy_command_options(const char *var, const char *value,
517                 void *cb)
518 {
519         if (!strcmp(var, "core.gitproxy")) {
520                 const char *for_pos;
521                 int matchlen = -1;
522                 int hostlen;
523                 const char *rhost_name = cb;
524                 int rhost_len = strlen(rhost_name);
525
526                 if (git_proxy_command)
527                         return 0;
528                 if (!value)
529                         return config_error_nonbool(var);
530                 /* [core]
531                  * ;# matches www.kernel.org as well
532                  * gitproxy = netcatter-1 for kernel.org
533                  * gitproxy = netcatter-2 for sample.xz
534                  * gitproxy = netcatter-default
535                  */
536                 for_pos = strstr(value, " for ");
537                 if (!for_pos)
538                         /* matches everybody */
539                         matchlen = strlen(value);
540                 else {
541                         hostlen = strlen(for_pos + 5);
542                         if (rhost_len < hostlen)
543                                 matchlen = -1;
544                         else if (!strncmp(for_pos + 5,
545                                           rhost_name + rhost_len - hostlen,
546                                           hostlen) &&
547                                  ((rhost_len == hostlen) ||
548                                   rhost_name[rhost_len - hostlen -1] == '.'))
549                                 matchlen = for_pos - value;
550                         else
551                                 matchlen = -1;
552                 }
553                 if (0 <= matchlen) {
554                         /* core.gitproxy = none for kernel.org */
555                         if (matchlen == 4 &&
556                             !memcmp(value, "none", 4))
557                                 matchlen = 0;
558                         git_proxy_command = xmemdupz(value, matchlen);
559                 }
560                 return 0;
561         }
562
563         return git_default_config(var, value, cb);
564 }
565
566 static int git_use_proxy(const char *host)
567 {
568         git_proxy_command = getenv("GIT_PROXY_COMMAND");
569         git_config(git_proxy_command_options, (void*)host);
570         return (git_proxy_command && *git_proxy_command);
571 }
572
573 static struct child_process *git_proxy_connect(int fd[2], char *host)
574 {
575         const char *port = STR(DEFAULT_GIT_PORT);
576         struct child_process *proxy;
577
578         get_host_and_port(&host, &port);
579
580         proxy = xmalloc(sizeof(*proxy));
581         child_process_init(proxy);
582         argv_array_push(&proxy->args, git_proxy_command);
583         argv_array_push(&proxy->args, host);
584         argv_array_push(&proxy->args, port);
585         proxy->in = -1;
586         proxy->out = -1;
587         if (start_command(proxy))
588                 die("cannot start proxy %s", git_proxy_command);
589         fd[0] = proxy->out; /* read from proxy stdout */
590         fd[1] = proxy->in;  /* write to proxy stdin */
591         return proxy;
592 }
593
594 static char *get_port(char *host)
595 {
596         char *end;
597         char *p = strchr(host, ':');
598
599         if (p) {
600                 long port = strtol(p + 1, &end, 10);
601                 if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
602                         *p = '\0';
603                         return p+1;
604                 }
605         }
606
607         return NULL;
608 }
609
610 /*
611  * Extract protocol and relevant parts from the specified connection URL.
612  * The caller must free() the returned strings.
613  */
614 static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
615                                        char **ret_path)
616 {
617         char *url;
618         char *host, *path;
619         char *end;
620         int separator = '/';
621         enum protocol protocol = PROTO_LOCAL;
622
623         if (is_url(url_orig))
624                 url = url_decode(url_orig);
625         else
626                 url = xstrdup(url_orig);
627
628         host = strstr(url, "://");
629         if (host) {
630                 *host = '\0';
631                 protocol = get_protocol(url);
632                 host += 3;
633         } else {
634                 host = url;
635                 if (!url_is_local_not_ssh(url)) {
636                         protocol = PROTO_SSH;
637                         separator = ':';
638                 }
639         }
640
641         /*
642          * Don't do destructive transforms as protocol code does
643          * '[]' unwrapping in get_host_and_port()
644          */
645         end = host_end(&host, 0);
646
647         if (protocol == PROTO_LOCAL)
648                 path = end;
649         else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
650                 path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
651         else
652                 path = strchr(end, separator);
653
654         if (!path || !*path)
655                 die("No path specified. See 'man git-pull' for valid url syntax");
656
657         /*
658          * null-terminate hostname and point path to ~ for URL's like this:
659          *    ssh://host.xz/~user/repo
660          */
661
662         end = path; /* Need to \0 terminate host here */
663         if (separator == ':')
664                 path++; /* path starts after ':' */
665         if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
666                 if (path[1] == '~')
667                         path++;
668         }
669
670         path = xstrdup(path);
671         *end = '\0';
672
673         *ret_host = xstrdup(host);
674         *ret_path = path;
675         free(url);
676         return protocol;
677 }
678
679 static struct child_process no_fork = CHILD_PROCESS_INIT;
680
681 static const char *get_ssh_command(void)
682 {
683         const char *ssh;
684
685         if ((ssh = getenv("GIT_SSH_COMMAND")))
686                 return ssh;
687
688         if (!git_config_get_string_const("core.sshcommand", &ssh))
689                 return ssh;
690
691         return NULL;
692 }
693
694 /*
695  * This returns a dummy child_process if the transport protocol does not
696  * need fork(2), or a struct child_process object if it does.  Once done,
697  * finish the connection with finish_connect() with the value returned from
698  * this function (it is safe to call finish_connect() with NULL to support
699  * the former case).
700  *
701  * If it returns, the connect is successful; it just dies on errors (this
702  * will hopefully be changed in a libification effort, to return NULL when
703  * the connection failed).
704  */
705 struct child_process *git_connect(int fd[2], const char *url,
706                                   const char *prog, int flags)
707 {
708         char *hostandport, *path;
709         struct child_process *conn = &no_fork;
710         enum protocol protocol;
711         struct strbuf cmd = STRBUF_INIT;
712
713         /* Without this we cannot rely on waitpid() to tell
714          * what happened to our children.
715          */
716         signal(SIGCHLD, SIG_DFL);
717
718         protocol = parse_connect_url(url, &hostandport, &path);
719         if ((flags & CONNECT_DIAG_URL) && (protocol != PROTO_SSH)) {
720                 printf("Diag: url=%s\n", url ? url : "NULL");
721                 printf("Diag: protocol=%s\n", prot_name(protocol));
722                 printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
723                 printf("Diag: path=%s\n", path ? path : "NULL");
724                 conn = NULL;
725         } else if (protocol == PROTO_GIT) {
726                 /*
727                  * Set up virtual host information based on where we will
728                  * connect, unless the user has overridden us in
729                  * the environment.
730                  */
731                 char *target_host = getenv("GIT_OVERRIDE_VIRTUAL_HOST");
732                 if (target_host)
733                         target_host = xstrdup(target_host);
734                 else
735                         target_host = xstrdup(hostandport);
736
737                 transport_check_allowed("git");
738
739                 /* These underlying connection commands die() if they
740                  * cannot connect.
741                  */
742                 if (git_use_proxy(hostandport))
743                         conn = git_proxy_connect(fd, hostandport);
744                 else
745                         git_tcp_connect(fd, hostandport, flags);
746                 /*
747                  * Separate original protocol components prog and path
748                  * from extended host header with a NUL byte.
749                  *
750                  * Note: Do not add any other headers here!  Doing so
751                  * will cause older git-daemon servers to crash.
752                  */
753                 packet_write_fmt(fd[1],
754                              "%s %s%chost=%s%c",
755                              prog, path, 0,
756                              target_host, 0);
757                 free(target_host);
758         } else {
759                 conn = xmalloc(sizeof(*conn));
760                 child_process_init(conn);
761
762                 strbuf_addstr(&cmd, prog);
763                 strbuf_addch(&cmd, ' ');
764                 sq_quote_buf(&cmd, path);
765
766                 /* remove repo-local variables from the environment */
767                 conn->env = local_repo_env;
768                 conn->use_shell = 1;
769                 conn->in = conn->out = -1;
770                 if (protocol == PROTO_SSH) {
771                         const char *ssh;
772                         int putty = 0, tortoiseplink = 0;
773                         char *ssh_host = hostandport;
774                         const char *port = NULL;
775                         transport_check_allowed("ssh");
776                         get_host_and_port(&ssh_host, &port);
777
778                         if (!port)
779                                 port = get_port(ssh_host);
780
781                         if (flags & CONNECT_DIAG_URL) {
782                                 printf("Diag: url=%s\n", url ? url : "NULL");
783                                 printf("Diag: protocol=%s\n", prot_name(protocol));
784                                 printf("Diag: userandhost=%s\n", ssh_host ? ssh_host : "NULL");
785                                 printf("Diag: port=%s\n", port ? port : "NONE");
786                                 printf("Diag: path=%s\n", path ? path : "NULL");
787
788                                 free(hostandport);
789                                 free(path);
790                                 free(conn);
791                                 return NULL;
792                         }
793
794                         ssh = get_ssh_command();
795                         if (!ssh) {
796                                 const char *base;
797                                 char *ssh_dup;
798
799                                 /*
800                                  * GIT_SSH is the no-shell version of
801                                  * GIT_SSH_COMMAND (and must remain so for
802                                  * historical compatibility).
803                                  */
804                                 conn->use_shell = 0;
805
806                                 ssh = getenv("GIT_SSH");
807                                 if (!ssh)
808                                         ssh = "ssh";
809
810                                 ssh_dup = xstrdup(ssh);
811                                 base = basename(ssh_dup);
812
813                                 tortoiseplink = !strcasecmp(base, "tortoiseplink") ||
814                                         !strcasecmp(base, "tortoiseplink.exe");
815                                 putty = tortoiseplink ||
816                                         !strcasecmp(base, "plink") ||
817                                         !strcasecmp(base, "plink.exe");
818
819                                 free(ssh_dup);
820                         }
821
822                         argv_array_push(&conn->args, ssh);
823                         if (flags & CONNECT_IPV4)
824                                 argv_array_push(&conn->args, "-4");
825                         else if (flags & CONNECT_IPV6)
826                                 argv_array_push(&conn->args, "-6");
827                         if (tortoiseplink)
828                                 argv_array_push(&conn->args, "-batch");
829                         if (port) {
830                                 /* P is for PuTTY, p is for OpenSSH */
831                                 argv_array_push(&conn->args, putty ? "-P" : "-p");
832                                 argv_array_push(&conn->args, port);
833                         }
834                         argv_array_push(&conn->args, ssh_host);
835                 } else {
836                         transport_check_allowed("file");
837                 }
838                 argv_array_push(&conn->args, cmd.buf);
839
840                 if (start_command(conn))
841                         die("unable to fork");
842
843                 fd[0] = conn->out; /* read from child's stdout */
844                 fd[1] = conn->in;  /* write to child's stdin */
845                 strbuf_release(&cmd);
846         }
847         free(hostandport);
848         free(path);
849         return conn;
850 }
851
852 int git_connection_is_socket(struct child_process *conn)
853 {
854         return conn == &no_fork;
855 }
856
857 int finish_connect(struct child_process *conn)
858 {
859         int code;
860         if (!conn || git_connection_is_socket(conn))
861                 return 0;
862
863         code = finish_command(conn);
864         free(conn);
865         return code;
866 }