user-manual: stub discussion of fsck and reflog
[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 unpack_limit = 100;
14 static int report_status;
15
16 static char capabilities[] = " report-status delete-refs ";
17 static int capabilities_sent;
18
19 static int receive_pack_config(const char *var, const char *value)
20 {
21         git_default_config(var, value);
22
23         if (strcmp(var, "receive.denynonfastforwards") == 0)
24         {
25                 deny_non_fast_forwards = git_config_bool(var, value);
26                 return 0;
27         }
28
29         if (strcmp(var, "receive.unpacklimit") == 0)
30         {
31                 unpack_limit = git_config_int(var, value);
32                 return 0;
33         }
34
35         return 0;
36 }
37
38 static int show_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
39 {
40         if (capabilities_sent)
41                 packet_write(1, "%s %s\n", sha1_to_hex(sha1), path);
42         else
43                 packet_write(1, "%s %s%c%s\n",
44                              sha1_to_hex(sha1), path, 0, capabilities);
45         capabilities_sent = 1;
46         return 0;
47 }
48
49 static void write_head_info(void)
50 {
51         for_each_ref(show_ref, NULL);
52         if (!capabilities_sent)
53                 show_ref("capabilities^{}", null_sha1, 0, NULL);
54
55 }
56
57 struct command {
58         struct command *next;
59         const char *error_string;
60         unsigned char old_sha1[20];
61         unsigned char new_sha1[20];
62         char ref_name[FLEX_ARRAY]; /* more */
63 };
64
65 static struct command *commands;
66
67 static char update_hook[] = "hooks/update";
68
69 static int run_update_hook(const char *refname,
70                            char *old_hex, char *new_hex)
71 {
72         int code;
73
74         if (access(update_hook, X_OK) < 0)
75                 return 0;
76         code = run_command_opt(RUN_COMMAND_NO_STDIN
77                 | RUN_COMMAND_STDOUT_TO_STDERR,
78                 update_hook, refname, old_hex, new_hex, NULL);
79         switch (code) {
80         case 0:
81                 return 0;
82         case -ERR_RUN_COMMAND_FORK:
83                 return error("hook fork failed");
84         case -ERR_RUN_COMMAND_EXEC:
85                 return error("hook execute failed");
86         case -ERR_RUN_COMMAND_WAITPID:
87                 return error("waitpid failed");
88         case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
89                 return error("waitpid is confused");
90         case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
91                 return error("%s died of signal", update_hook);
92         case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
93                 return error("%s died strangely", update_hook);
94         default:
95                 error("%s exited with error code %d", update_hook, -code);
96                 return -code;
97         }
98 }
99
100 static int update(struct command *cmd)
101 {
102         const char *name = cmd->ref_name;
103         unsigned char *old_sha1 = cmd->old_sha1;
104         unsigned char *new_sha1 = cmd->new_sha1;
105         char new_hex[41], old_hex[41];
106         struct ref_lock *lock;
107
108         cmd->error_string = NULL;
109         if (!strncmp(name, "refs/", 5) && check_ref_format(name + 5)) {
110                 cmd->error_string = "funny refname";
111                 return error("refusing to create funny ref '%s' locally",
112                              name);
113         }
114
115         strcpy(new_hex, sha1_to_hex(new_sha1));
116         strcpy(old_hex, sha1_to_hex(old_sha1));
117
118         if (!is_null_sha1(new_sha1) && !has_sha1_file(new_sha1)) {
119                 cmd->error_string = "bad pack";
120                 return error("unpack should have generated %s, "
121                              "but I can't find it!", new_hex);
122         }
123         if (deny_non_fast_forwards && !is_null_sha1(new_sha1) &&
124             !is_null_sha1(old_sha1) &&
125             !strncmp(name, "refs/heads/", 11)) {
126                 struct commit *old_commit, *new_commit;
127                 struct commit_list *bases, *ent;
128
129                 old_commit = (struct commit *)parse_object(old_sha1);
130                 new_commit = (struct commit *)parse_object(new_sha1);
131                 bases = get_merge_bases(old_commit, new_commit, 1);
132                 for (ent = bases; ent; ent = ent->next)
133                         if (!hashcmp(old_sha1, ent->item->object.sha1))
134                                 break;
135                 free_commit_list(bases);
136                 if (!ent)
137                         return error("denying non-fast forward;"
138                                      " you should pull first");
139         }
140         if (run_update_hook(name, old_hex, new_hex)) {
141                 cmd->error_string = "hook declined";
142                 return error("hook declined to update %s", name);
143         }
144
145         if (is_null_sha1(new_sha1)) {
146                 if (delete_ref(name, old_sha1)) {
147                         cmd->error_string = "failed to delete";
148                         return error("failed to delete %s", name);
149                 }
150                 fprintf(stderr, "%s: %s -> deleted\n", name, old_hex);
151         }
152         else {
153                 lock = lock_any_ref_for_update(name, old_sha1);
154                 if (!lock) {
155                         cmd->error_string = "failed to lock";
156                         return error("failed to lock %s", name);
157                 }
158                 write_ref_sha1(lock, new_sha1, "push");
159                 fprintf(stderr, "%s: %s -> %s\n", name, old_hex, new_hex);
160         }
161         return 0;
162 }
163
164 static char update_post_hook[] = "hooks/post-update";
165
166 static void run_update_post_hook(struct command *cmd)
167 {
168         struct command *cmd_p;
169         int argc;
170         const char **argv;
171
172         if (access(update_post_hook, X_OK) < 0)
173                 return;
174         for (argc = 1, cmd_p = cmd; cmd_p; cmd_p = cmd_p->next) {
175                 if (cmd_p->error_string)
176                         continue;
177                 argc++;
178         }
179         argv = xmalloc(sizeof(*argv) * (1 + argc));
180         argv[0] = update_post_hook;
181
182         for (argc = 1, cmd_p = cmd; cmd_p; cmd_p = cmd_p->next) {
183                 char *p;
184                 if (cmd_p->error_string)
185                         continue;
186                 p = xmalloc(strlen(cmd_p->ref_name) + 1);
187                 strcpy(p, cmd_p->ref_name);
188                 argv[argc] = p;
189                 argc++;
190         }
191         argv[argc] = NULL;
192         run_command_v_opt(argv, RUN_COMMAND_NO_STDIN
193                 | RUN_COMMAND_STDOUT_TO_STDERR);
194 }
195
196 /*
197  * This gets called after(if) we've successfully
198  * unpacked the data payload.
199  */
200 static void execute_commands(void)
201 {
202         struct command *cmd = commands;
203
204         while (cmd) {
205                 update(cmd);
206                 cmd = cmd->next;
207         }
208         run_update_post_hook(commands);
209 }
210
211 static void read_head_info(void)
212 {
213         struct command **p = &commands;
214         for (;;) {
215                 static char line[1000];
216                 unsigned char old_sha1[20], new_sha1[20];
217                 struct command *cmd;
218                 char *refname;
219                 int len, reflen;
220
221                 len = packet_read_line(0, line, sizeof(line));
222                 if (!len)
223                         break;
224                 if (line[len-1] == '\n')
225                         line[--len] = 0;
226                 if (len < 83 ||
227                     line[40] != ' ' ||
228                     line[81] != ' ' ||
229                     get_sha1_hex(line, old_sha1) ||
230                     get_sha1_hex(line + 41, new_sha1))
231                         die("protocol error: expected old/new/ref, got '%s'",
232                             line);
233
234                 refname = line + 82;
235                 reflen = strlen(refname);
236                 if (reflen + 82 < len) {
237                         if (strstr(refname + reflen + 1, "report-status"))
238                                 report_status = 1;
239                 }
240                 cmd = xmalloc(sizeof(struct command) + len - 80);
241                 hashcpy(cmd->old_sha1, old_sha1);
242                 hashcpy(cmd->new_sha1, new_sha1);
243                 memcpy(cmd->ref_name, line + 82, len - 81);
244                 cmd->error_string = "n/a (unpacker error)";
245                 cmd->next = NULL;
246                 *p = cmd;
247                 p = &cmd->next;
248         }
249 }
250
251 static const char *parse_pack_header(struct pack_header *hdr)
252 {
253         char *c = (char*)hdr;
254         ssize_t remaining = sizeof(struct pack_header);
255         do {
256                 ssize_t r = xread(0, c, remaining);
257                 if (r <= 0)
258                         return "eof before pack header was fully read";
259                 remaining -= r;
260                 c += r;
261         } while (remaining > 0);
262         if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
263                 return "protocol error (pack signature mismatch detected)";
264         if (!pack_version_ok(hdr->hdr_version))
265                 return "protocol error (pack version unsupported)";
266         return NULL;
267 }
268
269 static const char *pack_lockfile;
270
271 static const char *unpack(void)
272 {
273         struct pack_header hdr;
274         const char *hdr_err;
275         char hdr_arg[38];
276
277         hdr_err = parse_pack_header(&hdr);
278         if (hdr_err)
279                 return hdr_err;
280         snprintf(hdr_arg, sizeof(hdr_arg), "--pack_header=%u,%u",
281                         ntohl(hdr.hdr_version), ntohl(hdr.hdr_entries));
282
283         if (ntohl(hdr.hdr_entries) < unpack_limit) {
284                 int code;
285                 const char *unpacker[3];
286                 unpacker[0] = "unpack-objects";
287                 unpacker[1] = hdr_arg;
288                 unpacker[2] = NULL;
289                 code = run_command_v_opt(unpacker, RUN_GIT_CMD);
290                 switch (code) {
291                 case 0:
292                         return NULL;
293                 case -ERR_RUN_COMMAND_FORK:
294                         return "unpack fork failed";
295                 case -ERR_RUN_COMMAND_EXEC:
296                         return "unpack execute failed";
297                 case -ERR_RUN_COMMAND_WAITPID:
298                         return "waitpid failed";
299                 case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
300                         return "waitpid is confused";
301                 case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
302                         return "unpacker died of signal";
303                 case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
304                         return "unpacker died strangely";
305                 default:
306                         return "unpacker exited with error code";
307                 }
308         } else {
309                 const char *keeper[6];
310                 int fd[2], s, len, status;
311                 pid_t pid;
312                 char keep_arg[256];
313                 char packname[46];
314
315                 s = sprintf(keep_arg, "--keep=receive-pack %i on ", getpid());
316                 if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
317                         strcpy(keep_arg + s, "localhost");
318
319                 keeper[0] = "index-pack";
320                 keeper[1] = "--stdin";
321                 keeper[2] = "--fix-thin";
322                 keeper[3] = hdr_arg;
323                 keeper[4] = keep_arg;
324                 keeper[5] = NULL;
325
326                 if (pipe(fd) < 0)
327                         return "index-pack pipe failed";
328                 pid = fork();
329                 if (pid < 0)
330                         return "index-pack fork failed";
331                 if (!pid) {
332                         dup2(fd[1], 1);
333                         close(fd[1]);
334                         close(fd[0]);
335                         execv_git_cmd(keeper);
336                         die("execv of index-pack failed");
337                 }
338                 close(fd[1]);
339
340                 /*
341                  * The first thing we expects from index-pack's output
342                  * is "pack\t%40s\n" or "keep\t%40s\n" (46 bytes) where
343                  * %40s is the newly created pack SHA1 name.  In the "keep"
344                  * case, we need it to remove the corresponding .keep file
345                  * later on.  If we don't get that then tough luck with it.
346                  */
347                 for (len = 0;
348                      len < 46 && (s = xread(fd[0], packname+len, 46-len)) > 0;
349                      len += s);
350                 close(fd[0]);
351                 if (len == 46 && packname[45] == '\n' &&
352                     memcmp(packname, "keep\t", 5) == 0) {
353                         char path[PATH_MAX];
354                         packname[45] = 0;
355                         snprintf(path, sizeof(path), "%s/pack/pack-%s.keep",
356                                  get_object_directory(), packname + 5);
357                         pack_lockfile = xstrdup(path);
358                 }
359
360                 /* Then wrap our index-pack process. */
361                 while (waitpid(pid, &status, 0) < 0)
362                         if (errno != EINTR)
363                                 return "waitpid failed";
364                 if (WIFEXITED(status)) {
365                         int code = WEXITSTATUS(status);
366                         if (code)
367                                 return "index-pack exited with error code";
368                         reprepare_packed_git();
369                         return NULL;
370                 }
371                 return "index-pack abnormal exit";
372         }
373 }
374
375 static void report(const char *unpack_status)
376 {
377         struct command *cmd;
378         packet_write(1, "unpack %s\n",
379                      unpack_status ? unpack_status : "ok");
380         for (cmd = commands; cmd; cmd = cmd->next) {
381                 if (!cmd->error_string)
382                         packet_write(1, "ok %s\n",
383                                      cmd->ref_name);
384                 else
385                         packet_write(1, "ng %s %s\n",
386                                      cmd->ref_name, cmd->error_string);
387         }
388         packet_flush(1);
389 }
390
391 static int delete_only(struct command *cmd)
392 {
393         while (cmd) {
394                 if (!is_null_sha1(cmd->new_sha1))
395                         return 0;
396                 cmd = cmd->next;
397         }
398         return 1;
399 }
400
401 int main(int argc, char **argv)
402 {
403         int i;
404         char *dir = NULL;
405
406         argv++;
407         for (i = 1; i < argc; i++) {
408                 char *arg = *argv++;
409
410                 if (*arg == '-') {
411                         /* Do flag handling here */
412                         usage(receive_pack_usage);
413                 }
414                 if (dir)
415                         usage(receive_pack_usage);
416                 dir = arg;
417         }
418         if (!dir)
419                 usage(receive_pack_usage);
420
421         if (!enter_repo(dir, 0))
422                 die("'%s': unable to chdir or not a git archive", dir);
423
424         setup_ident();
425         /* don't die if gecos is empty */
426         ignore_missing_committer_name();
427         git_config(receive_pack_config);
428
429         write_head_info();
430
431         /* EOF */
432         packet_flush(1);
433
434         read_head_info();
435         if (commands) {
436                 const char *unpack_status = NULL;
437
438                 if (!delete_only(commands))
439                         unpack_status = unpack();
440                 if (!unpack_status)
441                         execute_commands();
442                 if (pack_lockfile)
443                         unlink(pack_lockfile);
444                 if (report_status)
445                         report(unpack_status);
446         }
447         return 0;
448 }