git checkout's reflog: even when detaching the HEAD, say from where
[git] / receive-pack.c
1 #include "cache.h"
2 #include "pack.h"
3 #include "refs.h"
4 #include "pkt-line.h"
5 #include "run-command.h"
6 #include "exec_cmd.h"
7 #include "commit.h"
8 #include "object.h"
9
10 static const char receive_pack_usage[] = "git-receive-pack <git-dir>";
11
12 static int deny_non_fast_forwards = 0;
13 static int receive_unpack_limit = -1;
14 static int transfer_unpack_limit = -1;
15 static int unpack_limit = 100;
16 static int report_status;
17
18 static char capabilities[] = " report-status delete-refs ";
19 static int capabilities_sent;
20
21 static int receive_pack_config(const char *var, const char *value)
22 {
23         if (strcmp(var, "receive.denynonfastforwards") == 0) {
24                 deny_non_fast_forwards = git_config_bool(var, value);
25                 return 0;
26         }
27
28         if (strcmp(var, "receive.unpacklimit") == 0) {
29                 receive_unpack_limit = git_config_int(var, value);
30                 return 0;
31         }
32
33         if (strcmp(var, "transfer.unpacklimit") == 0) {
34                 transfer_unpack_limit = git_config_int(var, value);
35                 return 0;
36         }
37
38         return git_default_config(var, value);
39 }
40
41 static int show_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
42 {
43         if (capabilities_sent)
44                 packet_write(1, "%s %s\n", sha1_to_hex(sha1), path);
45         else
46                 packet_write(1, "%s %s%c%s\n",
47                              sha1_to_hex(sha1), path, 0, capabilities);
48         capabilities_sent = 1;
49         return 0;
50 }
51
52 static void write_head_info(void)
53 {
54         for_each_ref(show_ref, NULL);
55         if (!capabilities_sent)
56                 show_ref("capabilities^{}", null_sha1, 0, NULL);
57
58 }
59
60 struct command {
61         struct command *next;
62         const char *error_string;
63         unsigned char old_sha1[20];
64         unsigned char new_sha1[20];
65         char ref_name[FLEX_ARRAY]; /* more */
66 };
67
68 static struct command *commands;
69
70 static const char pre_receive_hook[] = "hooks/pre-receive";
71 static const char post_receive_hook[] = "hooks/post-receive";
72
73 static int hook_status(int code, const char *hook_name)
74 {
75         switch (code) {
76         case 0:
77                 return 0;
78         case -ERR_RUN_COMMAND_FORK:
79                 return error("hook fork failed");
80         case -ERR_RUN_COMMAND_EXEC:
81                 return error("hook execute failed");
82         case -ERR_RUN_COMMAND_PIPE:
83                 return error("hook pipe failed");
84         case -ERR_RUN_COMMAND_WAITPID:
85                 return error("waitpid failed");
86         case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
87                 return error("waitpid is confused");
88         case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
89                 return error("%s died of signal", hook_name);
90         case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
91                 return error("%s died strangely", hook_name);
92         default:
93                 error("%s exited with error code %d", hook_name, -code);
94                 return -code;
95         }
96 }
97
98 static int run_hook(const char *hook_name)
99 {
100         static char buf[sizeof(commands->old_sha1) * 2 + PATH_MAX + 4];
101         struct command *cmd;
102         struct child_process proc;
103         const char *argv[2];
104         int have_input = 0, code;
105
106         for (cmd = commands; !have_input && cmd; cmd = cmd->next) {
107                 if (!cmd->error_string)
108                         have_input = 1;
109         }
110
111         if (!have_input || access(hook_name, X_OK) < 0)
112                 return 0;
113
114         argv[0] = hook_name;
115         argv[1] = NULL;
116
117         memset(&proc, 0, sizeof(proc));
118         proc.argv = argv;
119         proc.in = -1;
120         proc.stdout_to_stderr = 1;
121
122         code = start_command(&proc);
123         if (code)
124                 return hook_status(code, hook_name);
125         for (cmd = commands; cmd; cmd = cmd->next) {
126                 if (!cmd->error_string) {
127                         size_t n = snprintf(buf, sizeof(buf), "%s %s %s\n",
128                                 sha1_to_hex(cmd->old_sha1),
129                                 sha1_to_hex(cmd->new_sha1),
130                                 cmd->ref_name);
131                         if (write_in_full(proc.in, buf, n) != n)
132                                 break;
133                 }
134         }
135         return hook_status(finish_command(&proc), hook_name);
136 }
137
138 static int run_update_hook(struct command *cmd)
139 {
140         static const char update_hook[] = "hooks/update";
141         struct child_process proc;
142         const char *argv[5];
143
144         if (access(update_hook, X_OK) < 0)
145                 return 0;
146
147         argv[0] = update_hook;
148         argv[1] = cmd->ref_name;
149         argv[2] = sha1_to_hex(cmd->old_sha1);
150         argv[3] = sha1_to_hex(cmd->new_sha1);
151         argv[4] = NULL;
152
153         memset(&proc, 0, sizeof(proc));
154         proc.argv = argv;
155         proc.no_stdin = 1;
156         proc.stdout_to_stderr = 1;
157
158         return hook_status(run_command(&proc), update_hook);
159 }
160
161 static const char *update(struct command *cmd)
162 {
163         const char *name = cmd->ref_name;
164         unsigned char *old_sha1 = cmd->old_sha1;
165         unsigned char *new_sha1 = cmd->new_sha1;
166         struct ref_lock *lock;
167
168         if (!prefixcmp(name, "refs/") && check_ref_format(name + 5)) {
169                 error("refusing to create funny ref '%s' remotely", name);
170                 return "funny refname";
171         }
172
173         if (!is_null_sha1(new_sha1) && !has_sha1_file(new_sha1)) {
174                 error("unpack should have generated %s, "
175                       "but I can't find it!", sha1_to_hex(new_sha1));
176                 return "bad pack";
177         }
178         if (deny_non_fast_forwards && !is_null_sha1(new_sha1) &&
179             !is_null_sha1(old_sha1) &&
180             !prefixcmp(name, "refs/heads/")) {
181                 struct commit *old_commit, *new_commit;
182                 struct commit_list *bases, *ent;
183
184                 old_commit = (struct commit *)parse_object(old_sha1);
185                 new_commit = (struct commit *)parse_object(new_sha1);
186                 bases = get_merge_bases(old_commit, new_commit, 1);
187                 for (ent = bases; ent; ent = ent->next)
188                         if (!hashcmp(old_sha1, ent->item->object.sha1))
189                                 break;
190                 free_commit_list(bases);
191                 if (!ent) {
192                         error("denying non-fast forward %s"
193                               " (you should pull first)", name);
194                         return "non-fast forward";
195                 }
196         }
197         if (run_update_hook(cmd)) {
198                 error("hook declined to update %s", name);
199                 return "hook declined";
200         }
201
202         if (is_null_sha1(new_sha1)) {
203                 if (delete_ref(name, old_sha1)) {
204                         error("failed to delete %s", name);
205                         return "failed to delete";
206                 }
207                 return NULL; /* good */
208         }
209         else {
210                 lock = lock_any_ref_for_update(name, old_sha1, 0);
211                 if (!lock) {
212                         error("failed to lock %s", name);
213                         return "failed to lock";
214                 }
215                 if (write_ref_sha1(lock, new_sha1, "push")) {
216                         return "failed to write"; /* error() already called */
217                 }
218                 return NULL; /* good */
219         }
220 }
221
222 static char update_post_hook[] = "hooks/post-update";
223
224 static void run_update_post_hook(struct command *cmd)
225 {
226         struct command *cmd_p;
227         int argc;
228         const char **argv;
229
230         for (argc = 0, cmd_p = cmd; cmd_p; cmd_p = cmd_p->next) {
231                 if (cmd_p->error_string)
232                         continue;
233                 argc++;
234         }
235         if (!argc || access(update_post_hook, X_OK) < 0)
236                 return;
237         argv = xmalloc(sizeof(*argv) * (2 + argc));
238         argv[0] = update_post_hook;
239
240         for (argc = 1, cmd_p = cmd; cmd_p; cmd_p = cmd_p->next) {
241                 char *p;
242                 if (cmd_p->error_string)
243                         continue;
244                 p = xmalloc(strlen(cmd_p->ref_name) + 1);
245                 strcpy(p, cmd_p->ref_name);
246                 argv[argc] = p;
247                 argc++;
248         }
249         argv[argc] = NULL;
250         run_command_v_opt(argv, RUN_COMMAND_NO_STDIN
251                 | RUN_COMMAND_STDOUT_TO_STDERR);
252 }
253
254 static void execute_commands(const char *unpacker_error)
255 {
256         struct command *cmd = commands;
257
258         if (unpacker_error) {
259                 while (cmd) {
260                         cmd->error_string = "n/a (unpacker error)";
261                         cmd = cmd->next;
262                 }
263                 return;
264         }
265
266         if (run_hook(pre_receive_hook)) {
267                 while (cmd) {
268                         cmd->error_string = "pre-receive hook declined";
269                         cmd = cmd->next;
270                 }
271                 return;
272         }
273
274         while (cmd) {
275                 cmd->error_string = update(cmd);
276                 cmd = cmd->next;
277         }
278 }
279
280 static void read_head_info(void)
281 {
282         struct command **p = &commands;
283         for (;;) {
284                 static char line[1000];
285                 unsigned char old_sha1[20], new_sha1[20];
286                 struct command *cmd;
287                 char *refname;
288                 int len, reflen;
289
290                 len = packet_read_line(0, line, sizeof(line));
291                 if (!len)
292                         break;
293                 if (line[len-1] == '\n')
294                         line[--len] = 0;
295                 if (len < 83 ||
296                     line[40] != ' ' ||
297                     line[81] != ' ' ||
298                     get_sha1_hex(line, old_sha1) ||
299                     get_sha1_hex(line + 41, new_sha1))
300                         die("protocol error: expected old/new/ref, got '%s'",
301                             line);
302
303                 refname = line + 82;
304                 reflen = strlen(refname);
305                 if (reflen + 82 < len) {
306                         if (strstr(refname + reflen + 1, "report-status"))
307                                 report_status = 1;
308                 }
309                 cmd = xmalloc(sizeof(struct command) + len - 80);
310                 hashcpy(cmd->old_sha1, old_sha1);
311                 hashcpy(cmd->new_sha1, new_sha1);
312                 memcpy(cmd->ref_name, line + 82, len - 81);
313                 cmd->error_string = NULL;
314                 cmd->next = NULL;
315                 *p = cmd;
316                 p = &cmd->next;
317         }
318 }
319
320 static const char *parse_pack_header(struct pack_header *hdr)
321 {
322         switch (read_pack_header(0, hdr)) {
323         case PH_ERROR_EOF:
324                 return "eof before pack header was fully read";
325
326         case PH_ERROR_PACK_SIGNATURE:
327                 return "protocol error (pack signature mismatch detected)";
328
329         case PH_ERROR_PROTOCOL:
330                 return "protocol error (pack version unsupported)";
331
332         default:
333                 return "unknown error in parse_pack_header";
334
335         case 0:
336                 return NULL;
337         }
338 }
339
340 static const char *pack_lockfile;
341
342 static const char *unpack(void)
343 {
344         struct pack_header hdr;
345         const char *hdr_err;
346         char hdr_arg[38];
347
348         hdr_err = parse_pack_header(&hdr);
349         if (hdr_err)
350                 return hdr_err;
351         snprintf(hdr_arg, sizeof(hdr_arg), "--pack_header=%u,%u",
352                         ntohl(hdr.hdr_version), ntohl(hdr.hdr_entries));
353
354         if (ntohl(hdr.hdr_entries) < unpack_limit) {
355                 int code;
356                 const char *unpacker[3];
357                 unpacker[0] = "unpack-objects";
358                 unpacker[1] = hdr_arg;
359                 unpacker[2] = NULL;
360                 code = run_command_v_opt(unpacker, RUN_GIT_CMD);
361                 switch (code) {
362                 case 0:
363                         return NULL;
364                 case -ERR_RUN_COMMAND_FORK:
365                         return "unpack fork failed";
366                 case -ERR_RUN_COMMAND_EXEC:
367                         return "unpack execute failed";
368                 case -ERR_RUN_COMMAND_WAITPID:
369                         return "waitpid failed";
370                 case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
371                         return "waitpid is confused";
372                 case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
373                         return "unpacker died of signal";
374                 case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
375                         return "unpacker died strangely";
376                 default:
377                         return "unpacker exited with error code";
378                 }
379         } else {
380                 const char *keeper[6];
381                 int s, status;
382                 char keep_arg[256];
383                 struct child_process ip;
384
385                 s = sprintf(keep_arg, "--keep=receive-pack %i on ", getpid());
386                 if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
387                         strcpy(keep_arg + s, "localhost");
388
389                 keeper[0] = "index-pack";
390                 keeper[1] = "--stdin";
391                 keeper[2] = "--fix-thin";
392                 keeper[3] = hdr_arg;
393                 keeper[4] = keep_arg;
394                 keeper[5] = NULL;
395                 memset(&ip, 0, sizeof(ip));
396                 ip.argv = keeper;
397                 ip.out = -1;
398                 ip.git_cmd = 1;
399                 if (start_command(&ip))
400                         return "index-pack fork failed";
401                 pack_lockfile = index_pack_lockfile(ip.out);
402                 status = finish_command(&ip);
403                 if (!status) {
404                         reprepare_packed_git();
405                         return NULL;
406                 }
407                 return "index-pack abnormal exit";
408         }
409 }
410
411 static void report(const char *unpack_status)
412 {
413         struct command *cmd;
414         packet_write(1, "unpack %s\n",
415                      unpack_status ? unpack_status : "ok");
416         for (cmd = commands; cmd; cmd = cmd->next) {
417                 if (!cmd->error_string)
418                         packet_write(1, "ok %s\n",
419                                      cmd->ref_name);
420                 else
421                         packet_write(1, "ng %s %s\n",
422                                      cmd->ref_name, cmd->error_string);
423         }
424         packet_flush(1);
425 }
426
427 static int delete_only(struct command *cmd)
428 {
429         while (cmd) {
430                 if (!is_null_sha1(cmd->new_sha1))
431                         return 0;
432                 cmd = cmd->next;
433         }
434         return 1;
435 }
436
437 int main(int argc, char **argv)
438 {
439         int i;
440         char *dir = NULL;
441
442         argv++;
443         for (i = 1; i < argc; i++) {
444                 char *arg = *argv++;
445
446                 if (*arg == '-') {
447                         /* Do flag handling here */
448                         usage(receive_pack_usage);
449                 }
450                 if (dir)
451                         usage(receive_pack_usage);
452                 dir = arg;
453         }
454         if (!dir)
455                 usage(receive_pack_usage);
456
457         if (!enter_repo(dir, 0))
458                 die("'%s': unable to chdir or not a git archive", dir);
459
460         if (is_repository_shallow())
461                 die("attempt to push into a shallow repository");
462
463         git_config(receive_pack_config);
464
465         if (0 <= transfer_unpack_limit)
466                 unpack_limit = transfer_unpack_limit;
467         else if (0 <= receive_unpack_limit)
468                 unpack_limit = receive_unpack_limit;
469
470         write_head_info();
471
472         /* EOF */
473         packet_flush(1);
474
475         read_head_info();
476         if (commands) {
477                 const char *unpack_status = NULL;
478
479                 if (!delete_only(commands))
480                         unpack_status = unpack();
481                 execute_commands(unpack_status);
482                 if (pack_lockfile)
483                         unlink(pack_lockfile);
484                 if (report_status)
485                         report(unpack_status);
486                 run_hook(post_receive_hook);
487                 run_update_post_hook(commands);
488         }
489         return 0;
490 }