t: redirect stderr GIT_TRACE to descriptor 4
[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
13 static char *server_capabilities;
14 static const char *parse_feature_value(const char *, const char *, int *);
15
16 static int check_ref(const char *name, unsigned int flags)
17 {
18         if (!flags)
19                 return 1;
20
21         if (!skip_prefix(name, "refs/", &name))
22                 return 0;
23
24         /* REF_NORMAL means that we don't want the magic fake tag refs */
25         if ((flags & REF_NORMAL) && check_refname_format(name, 0))
26                 return 0;
27
28         /* REF_HEADS means that we want regular branch heads */
29         if ((flags & REF_HEADS) && starts_with(name, "heads/"))
30                 return 1;
31
32         /* REF_TAGS means that we want tags */
33         if ((flags & REF_TAGS) && starts_with(name, "tags/"))
34                 return 1;
35
36         /* All type bits clear means that we are ok with anything */
37         return !(flags & ~REF_NORMAL);
38 }
39
40 int check_ref_type(const struct ref *ref, int flags)
41 {
42         return check_ref(ref->name, flags);
43 }
44
45 static void die_initial_contact(int got_at_least_one_head)
46 {
47         if (got_at_least_one_head)
48                 die("The remote end hung up upon initial contact");
49         else
50                 die("Could not read from remote repository.\n\n"
51                     "Please make sure you have the correct access rights\n"
52                     "and the repository exists.");
53 }
54
55 static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
56 {
57         char *sym, *target;
58         struct string_list_item *item;
59
60         if (!len)
61                 return; /* just "symref" */
62         /* e.g. "symref=HEAD:refs/heads/master" */
63         sym = xmemdupz(val, len);
64         target = strchr(sym, ':');
65         if (!target)
66                 /* just "symref=something" */
67                 goto reject;
68         *(target++) = '\0';
69         if (check_refname_format(sym, REFNAME_ALLOW_ONELEVEL) ||
70             check_refname_format(target, REFNAME_ALLOW_ONELEVEL))
71                 /* "symref=bogus:pair */
72                 goto reject;
73         item = string_list_append(symref, sym);
74         item->util = target;
75         return;
76 reject:
77         free(sym);
78         return;
79 }
80
81 static void annotate_refs_with_symref_info(struct ref *ref)
82 {
83         struct string_list symref = STRING_LIST_INIT_DUP;
84         const char *feature_list = server_capabilities;
85
86         while (feature_list) {
87                 int len;
88                 const char *val;
89
90                 val = parse_feature_value(feature_list, "symref", &len);
91                 if (!val)
92                         break;
93                 parse_one_symref_info(&symref, val, len);
94                 feature_list = val + 1;
95         }
96         string_list_sort(&symref);
97
98         for (; ref; ref = ref->next) {
99                 struct string_list_item *item;
100                 item = string_list_lookup(&symref, ref->name);
101                 if (!item)
102                         continue;
103                 ref->symref = xstrdup((char *)item->util);
104         }
105         string_list_clear(&symref, 0);
106 }
107
108 /*
109  * Read all the refs from the other end
110  */
111 struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
112                               struct ref **list, unsigned int flags,
113                               struct sha1_array *extra_have,
114                               struct sha1_array *shallow_points)
115 {
116         struct ref **orig_list = list;
117         int got_at_least_one_head = 0;
118
119         *list = NULL;
120         for (;;) {
121                 struct ref *ref;
122                 unsigned char old_sha1[20];
123                 char *name;
124                 int len, name_len;
125                 char *buffer = packet_buffer;
126                 const char *arg;
127
128                 len = packet_read(in, &src_buf, &src_len,
129                                   packet_buffer, sizeof(packet_buffer),
130                                   PACKET_READ_GENTLE_ON_EOF |
131                                   PACKET_READ_CHOMP_NEWLINE);
132                 if (len < 0)
133                         die_initial_contact(got_at_least_one_head);
134
135                 if (!len)
136                         break;
137
138                 if (len > 4 && skip_prefix(buffer, "ERR ", &arg))
139                         die("remote error: %s", arg);
140
141                 if (len == 48 && skip_prefix(buffer, "shallow ", &arg)) {
142                         if (get_sha1_hex(arg, old_sha1))
143                                 die("protocol error: expected shallow sha-1, got '%s'", arg);
144                         if (!shallow_points)
145                                 die("repository on the other end cannot be shallow");
146                         sha1_array_append(shallow_points, old_sha1);
147                         continue;
148                 }
149
150                 if (len < 42 || get_sha1_hex(buffer, old_sha1) || buffer[40] != ' ')
151                         die("protocol error: expected sha/ref, got '%s'", buffer);
152                 name = buffer + 41;
153
154                 name_len = strlen(name);
155                 if (len != name_len + 41) {
156                         free(server_capabilities);
157                         server_capabilities = xstrdup(name + name_len + 1);
158                 }
159
160                 if (extra_have && !strcmp(name, ".have")) {
161                         sha1_array_append(extra_have, old_sha1);
162                         continue;
163                 }
164
165                 if (!check_ref(name, flags))
166                         continue;
167                 ref = alloc_ref(buffer + 41);
168                 hashcpy(ref->old_sha1, old_sha1);
169                 *list = ref;
170                 list = &ref->next;
171                 got_at_least_one_head = 1;
172         }
173
174         annotate_refs_with_symref_info(*orig_list);
175
176         return list;
177 }
178
179 static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
180 {
181         int len;
182
183         if (!feature_list)
184                 return NULL;
185
186         len = strlen(feature);
187         while (*feature_list) {
188                 const char *found = strstr(feature_list, feature);
189                 if (!found)
190                         return NULL;
191                 if (feature_list == found || isspace(found[-1])) {
192                         const char *value = found + len;
193                         /* feature with no value (e.g., "thin-pack") */
194                         if (!*value || isspace(*value)) {
195                                 if (lenp)
196                                         *lenp = 0;
197                                 return value;
198                         }
199                         /* feature with a value (e.g., "agent=git/1.2.3") */
200                         else if (*value == '=') {
201                                 value++;
202                                 if (lenp)
203                                         *lenp = strcspn(value, " \t\n");
204                                 return value;
205                         }
206                         /*
207                          * otherwise we matched a substring of another feature;
208                          * keep looking
209                          */
210                 }
211                 feature_list = found + 1;
212         }
213         return NULL;
214 }
215
216 int parse_feature_request(const char *feature_list, const char *feature)
217 {
218         return !!parse_feature_value(feature_list, feature, NULL);
219 }
220
221 const char *server_feature_value(const char *feature, int *len)
222 {
223         return parse_feature_value(server_capabilities, feature, len);
224 }
225
226 int server_supports(const char *feature)
227 {
228         return !!server_feature_value(feature, NULL);
229 }
230
231 enum protocol {
232         PROTO_LOCAL = 1,
233         PROTO_FILE,
234         PROTO_SSH,
235         PROTO_GIT
236 };
237
238 int url_is_local_not_ssh(const char *url)
239 {
240         const char *colon = strchr(url, ':');
241         const char *slash = strchr(url, '/');
242         return !colon || (slash && slash < colon) ||
243                 has_dos_drive_prefix(url);
244 }
245
246 static const char *prot_name(enum protocol protocol)
247 {
248         switch (protocol) {
249                 case PROTO_LOCAL:
250                 case PROTO_FILE:
251                         return "file";
252                 case PROTO_SSH:
253                         return "ssh";
254                 case PROTO_GIT:
255                         return "git";
256                 default:
257                         return "unkown protocol";
258         }
259 }
260
261 static enum protocol get_protocol(const char *name)
262 {
263         if (!strcmp(name, "ssh"))
264                 return PROTO_SSH;
265         if (!strcmp(name, "git"))
266                 return PROTO_GIT;
267         if (!strcmp(name, "git+ssh"))
268                 return PROTO_SSH;
269         if (!strcmp(name, "ssh+git"))
270                 return PROTO_SSH;
271         if (!strcmp(name, "file"))
272                 return PROTO_FILE;
273         die("I don't handle protocol '%s'", name);
274 }
275
276 #define STR_(s) # s
277 #define STR(s)  STR_(s)
278
279 static void get_host_and_port(char **host, const char **port)
280 {
281         char *colon, *end;
282
283         if (*host[0] == '[') {
284                 end = strchr(*host + 1, ']');
285                 if (end) {
286                         *end = 0;
287                         end++;
288                         (*host)++;
289                 } else
290                         end = *host;
291         } else
292                 end = *host;
293         colon = strchr(end, ':');
294
295         if (colon) {
296                 *colon = 0;
297                 *port = colon + 1;
298         }
299 }
300
301 static void enable_keepalive(int sockfd)
302 {
303         int ka = 1;
304
305         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
306                 fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n",
307                         strerror(errno));
308 }
309
310 #ifndef NO_IPV6
311
312 static const char *ai_name(const struct addrinfo *ai)
313 {
314         static char addr[NI_MAXHOST];
315         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
316                         NI_NUMERICHOST) != 0)
317                 strcpy(addr, "(unknown)");
318
319         return addr;
320 }
321
322 /*
323  * Returns a connected socket() fd, or else die()s.
324  */
325 static int git_tcp_connect_sock(char *host, int flags)
326 {
327         struct strbuf error_message = STRBUF_INIT;
328         int sockfd = -1;
329         const char *port = STR(DEFAULT_GIT_PORT);
330         struct addrinfo hints, *ai0, *ai;
331         int gai;
332         int cnt = 0;
333
334         get_host_and_port(&host, &port);
335         if (!*port)
336                 port = "<none>";
337
338         memset(&hints, 0, sizeof(hints));
339         hints.ai_socktype = SOCK_STREAM;
340         hints.ai_protocol = IPPROTO_TCP;
341
342         if (flags & CONNECT_VERBOSE)
343                 fprintf(stderr, "Looking up %s ... ", host);
344
345         gai = getaddrinfo(host, port, &hints, &ai);
346         if (gai)
347                 die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
348
349         if (flags & CONNECT_VERBOSE)
350                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
351
352         for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
353                 sockfd = socket(ai->ai_family,
354                                 ai->ai_socktype, ai->ai_protocol);
355                 if ((sockfd < 0) ||
356                     (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
357                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
358                                     host, cnt, ai_name(ai), strerror(errno));
359                         if (0 <= sockfd)
360                                 close(sockfd);
361                         sockfd = -1;
362                         continue;
363                 }
364                 if (flags & CONNECT_VERBOSE)
365                         fprintf(stderr, "%s ", ai_name(ai));
366                 break;
367         }
368
369         freeaddrinfo(ai0);
370
371         if (sockfd < 0)
372                 die("unable to connect to %s:\n%s", host, error_message.buf);
373
374         enable_keepalive(sockfd);
375
376         if (flags & CONNECT_VERBOSE)
377                 fprintf(stderr, "done.\n");
378
379         strbuf_release(&error_message);
380
381         return sockfd;
382 }
383
384 #else /* NO_IPV6 */
385
386 /*
387  * Returns a connected socket() fd, or else die()s.
388  */
389 static int git_tcp_connect_sock(char *host, int flags)
390 {
391         struct strbuf error_message = STRBUF_INIT;
392         int sockfd = -1;
393         const char *port = STR(DEFAULT_GIT_PORT);
394         char *ep;
395         struct hostent *he;
396         struct sockaddr_in sa;
397         char **ap;
398         unsigned int nport;
399         int cnt;
400
401         get_host_and_port(&host, &port);
402
403         if (flags & CONNECT_VERBOSE)
404                 fprintf(stderr, "Looking up %s ... ", host);
405
406         he = gethostbyname(host);
407         if (!he)
408                 die("Unable to look up %s (%s)", host, hstrerror(h_errno));
409         nport = strtoul(port, &ep, 10);
410         if ( ep == port || *ep ) {
411                 /* Not numeric */
412                 struct servent *se = getservbyname(port,"tcp");
413                 if ( !se )
414                         die("Unknown port %s", port);
415                 nport = se->s_port;
416         }
417
418         if (flags & CONNECT_VERBOSE)
419                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
420
421         for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
422                 memset(&sa, 0, sizeof sa);
423                 sa.sin_family = he->h_addrtype;
424                 sa.sin_port = htons(nport);
425                 memcpy(&sa.sin_addr, *ap, he->h_length);
426
427                 sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
428                 if ((sockfd < 0) ||
429                     connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
430                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
431                                 host,
432                                 cnt,
433                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr),
434                                 strerror(errno));
435                         if (0 <= sockfd)
436                                 close(sockfd);
437                         sockfd = -1;
438                         continue;
439                 }
440                 if (flags & CONNECT_VERBOSE)
441                         fprintf(stderr, "%s ",
442                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr));
443                 break;
444         }
445
446         if (sockfd < 0)
447                 die("unable to connect to %s:\n%s", host, error_message.buf);
448
449         enable_keepalive(sockfd);
450
451         if (flags & CONNECT_VERBOSE)
452                 fprintf(stderr, "done.\n");
453
454         return sockfd;
455 }
456
457 #endif /* NO_IPV6 */
458
459
460 static void git_tcp_connect(int fd[2], char *host, int flags)
461 {
462         int sockfd = git_tcp_connect_sock(host, flags);
463
464         fd[0] = sockfd;
465         fd[1] = dup(sockfd);
466 }
467
468
469 static char *git_proxy_command;
470
471 static int git_proxy_command_options(const char *var, const char *value,
472                 void *cb)
473 {
474         if (!strcmp(var, "core.gitproxy")) {
475                 const char *for_pos;
476                 int matchlen = -1;
477                 int hostlen;
478                 const char *rhost_name = cb;
479                 int rhost_len = strlen(rhost_name);
480
481                 if (git_proxy_command)
482                         return 0;
483                 if (!value)
484                         return config_error_nonbool(var);
485                 /* [core]
486                  * ;# matches www.kernel.org as well
487                  * gitproxy = netcatter-1 for kernel.org
488                  * gitproxy = netcatter-2 for sample.xz
489                  * gitproxy = netcatter-default
490                  */
491                 for_pos = strstr(value, " for ");
492                 if (!for_pos)
493                         /* matches everybody */
494                         matchlen = strlen(value);
495                 else {
496                         hostlen = strlen(for_pos + 5);
497                         if (rhost_len < hostlen)
498                                 matchlen = -1;
499                         else if (!strncmp(for_pos + 5,
500                                           rhost_name + rhost_len - hostlen,
501                                           hostlen) &&
502                                  ((rhost_len == hostlen) ||
503                                   rhost_name[rhost_len - hostlen -1] == '.'))
504                                 matchlen = for_pos - value;
505                         else
506                                 matchlen = -1;
507                 }
508                 if (0 <= matchlen) {
509                         /* core.gitproxy = none for kernel.org */
510                         if (matchlen == 4 &&
511                             !memcmp(value, "none", 4))
512                                 matchlen = 0;
513                         git_proxy_command = xmemdupz(value, matchlen);
514                 }
515                 return 0;
516         }
517
518         return git_default_config(var, value, cb);
519 }
520
521 static int git_use_proxy(const char *host)
522 {
523         git_proxy_command = getenv("GIT_PROXY_COMMAND");
524         git_config(git_proxy_command_options, (void*)host);
525         return (git_proxy_command && *git_proxy_command);
526 }
527
528 static struct child_process *git_proxy_connect(int fd[2], char *host)
529 {
530         const char *port = STR(DEFAULT_GIT_PORT);
531         struct child_process *proxy;
532
533         get_host_and_port(&host, &port);
534
535         proxy = xmalloc(sizeof(*proxy));
536         child_process_init(proxy);
537         argv_array_push(&proxy->args, git_proxy_command);
538         argv_array_push(&proxy->args, host);
539         argv_array_push(&proxy->args, port);
540         proxy->in = -1;
541         proxy->out = -1;
542         if (start_command(proxy))
543                 die("cannot start proxy %s", git_proxy_command);
544         fd[0] = proxy->out; /* read from proxy stdout */
545         fd[1] = proxy->in;  /* write to proxy stdin */
546         return proxy;
547 }
548
549 static const char *get_port_numeric(const char *p)
550 {
551         char *end;
552         if (p) {
553                 long port = strtol(p + 1, &end, 10);
554                 if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
555                         return p;
556                 }
557         }
558
559         return NULL;
560 }
561
562 /*
563  * Extract protocol and relevant parts from the specified connection URL.
564  * The caller must free() the returned strings.
565  */
566 static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
567                                        char **ret_path)
568 {
569         char *url;
570         char *host, *path;
571         char *end;
572         int separator = '/';
573         enum protocol protocol = PROTO_LOCAL;
574
575         if (is_url(url_orig))
576                 url = url_decode(url_orig);
577         else
578                 url = xstrdup(url_orig);
579
580         host = strstr(url, "://");
581         if (host) {
582                 *host = '\0';
583                 protocol = get_protocol(url);
584                 host += 3;
585         } else {
586                 host = url;
587                 if (!url_is_local_not_ssh(url)) {
588                         protocol = PROTO_SSH;
589                         separator = ':';
590                 }
591         }
592
593         /*
594          * Don't do destructive transforms as protocol code does
595          * '[]' unwrapping in get_host_and_port()
596          */
597         if (host[0] == '[') {
598                 end = strchr(host + 1, ']');
599                 if (end) {
600                         end++;
601                 } else
602                         end = host;
603         } else
604                 end = host;
605
606         if (protocol == PROTO_LOCAL)
607                 path = end;
608         else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
609                 path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
610         else
611                 path = strchr(end, separator);
612
613         if (!path || !*path)
614                 die("No path specified. See 'man git-pull' for valid url syntax");
615
616         /*
617          * null-terminate hostname and point path to ~ for URL's like this:
618          *    ssh://host.xz/~user/repo
619          */
620
621         end = path; /* Need to \0 terminate host here */
622         if (separator == ':')
623                 path++; /* path starts after ':' */
624         if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
625                 if (path[1] == '~')
626                         path++;
627         }
628
629         path = xstrdup(path);
630         *end = '\0';
631
632         *ret_host = xstrdup(host);
633         *ret_path = path;
634         free(url);
635         return protocol;
636 }
637
638 static struct child_process no_fork = CHILD_PROCESS_INIT;
639
640 /*
641  * This returns a dummy child_process if the transport protocol does not
642  * need fork(2), or a struct child_process object if it does.  Once done,
643  * finish the connection with finish_connect() with the value returned from
644  * this function (it is safe to call finish_connect() with NULL to support
645  * the former case).
646  *
647  * If it returns, the connect is successful; it just dies on errors (this
648  * will hopefully be changed in a libification effort, to return NULL when
649  * the connection failed).
650  */
651 struct child_process *git_connect(int fd[2], const char *url,
652                                   const char *prog, int flags)
653 {
654         char *hostandport, *path;
655         struct child_process *conn = &no_fork;
656         enum protocol protocol;
657         struct strbuf cmd = STRBUF_INIT;
658
659         /* Without this we cannot rely on waitpid() to tell
660          * what happened to our children.
661          */
662         signal(SIGCHLD, SIG_DFL);
663
664         protocol = parse_connect_url(url, &hostandport, &path);
665         if (flags & CONNECT_DIAG_URL) {
666                 printf("Diag: url=%s\n", url ? url : "NULL");
667                 printf("Diag: protocol=%s\n", prot_name(protocol));
668                 printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
669                 printf("Diag: path=%s\n", path ? path : "NULL");
670                 conn = NULL;
671         } else if (protocol == PROTO_GIT) {
672                 /* These underlying connection commands die() if they
673                  * cannot connect.
674                  */
675                 char *target_host = xstrdup(hostandport);
676                 if (git_use_proxy(hostandport))
677                         conn = git_proxy_connect(fd, hostandport);
678                 else
679                         git_tcp_connect(fd, hostandport, flags);
680                 /*
681                  * Separate original protocol components prog and path
682                  * from extended host header with a NUL byte.
683                  *
684                  * Note: Do not add any other headers here!  Doing so
685                  * will cause older git-daemon servers to crash.
686                  */
687                 packet_write(fd[1],
688                              "%s %s%chost=%s%c",
689                              prog, path, 0,
690                              target_host, 0);
691                 free(target_host);
692         } else {
693                 conn = xmalloc(sizeof(*conn));
694                 child_process_init(conn);
695
696                 strbuf_addstr(&cmd, prog);
697                 strbuf_addch(&cmd, ' ');
698                 sq_quote_buf(&cmd, path);
699
700                 conn->in = conn->out = -1;
701                 if (protocol == PROTO_SSH) {
702                         const char *ssh;
703                         int putty;
704                         char *ssh_host = hostandport;
705                         const char *port = NULL;
706                         get_host_and_port(&ssh_host, &port);
707                         port = get_port_numeric(port);
708
709                         ssh = getenv("GIT_SSH_COMMAND");
710                         if (ssh) {
711                                 conn->use_shell = 1;
712                                 putty = 0;
713                         } else {
714                                 ssh = getenv("GIT_SSH");
715                                 if (!ssh)
716                                         ssh = "ssh";
717                                 putty = !!strcasestr(ssh, "plink");
718                         }
719
720                         argv_array_push(&conn->args, ssh);
721                         if (putty && !strcasestr(ssh, "tortoiseplink"))
722                                 argv_array_push(&conn->args, "-batch");
723                         if (port) {
724                                 /* P is for PuTTY, p is for OpenSSH */
725                                 argv_array_push(&conn->args, putty ? "-P" : "-p");
726                                 argv_array_push(&conn->args, port);
727                         }
728                         argv_array_push(&conn->args, ssh_host);
729                 } else {
730                         /* remove repo-local variables from the environment */
731                         conn->env = local_repo_env;
732                         conn->use_shell = 1;
733                 }
734                 argv_array_push(&conn->args, cmd.buf);
735
736                 if (start_command(conn))
737                         die("unable to fork");
738
739                 fd[0] = conn->out; /* read from child's stdout */
740                 fd[1] = conn->in;  /* write to child's stdin */
741                 strbuf_release(&cmd);
742         }
743         free(hostandport);
744         free(path);
745         return conn;
746 }
747
748 int git_connection_is_socket(struct child_process *conn)
749 {
750         return conn == &no_fork;
751 }
752
753 int finish_connect(struct child_process *conn)
754 {
755         int code;
756         if (!conn || git_connection_is_socket(conn))
757                 return 0;
758
759         code = finish_command(conn);
760         free(conn);
761         return code;
762 }