Add a Documentation/git-tools.txt
[git] / receive-pack.c
1 #include "cache.h"
2 #include "refs.h"
3 #include "pkt-line.h"
4 #include "run-command.h"
5 #include <sys/wait.h>
6
7 static const char receive_pack_usage[] = "git-receive-pack <git-dir>";
8
9 static char *unpacker[] = { "unpack-objects", NULL };
10
11 static int report_status = 0;
12
13 static char capabilities[] = "report-status";
14 static int capabilities_sent = 0;
15
16 static int show_ref(const char *path, const unsigned char *sha1)
17 {
18         if (capabilities_sent)
19                 packet_write(1, "%s %s\n", sha1_to_hex(sha1), path);
20         else
21                 packet_write(1, "%s %s%c%s\n",
22                              sha1_to_hex(sha1), path, 0, capabilities);
23         capabilities_sent = 1;
24         return 0;
25 }
26
27 static void write_head_info(void)
28 {
29         for_each_ref(show_ref);
30         if (!capabilities_sent)
31                 show_ref("capabilities^{}", null_sha1);
32
33 }
34
35 struct command {
36         struct command *next;
37         const char *error_string;
38         unsigned char old_sha1[20];
39         unsigned char new_sha1[20];
40         char ref_name[FLEX_ARRAY]; /* more */
41 };
42
43 static struct command *commands = NULL;
44
45 static int is_all_zeroes(const char *hex)
46 {
47         int i;
48         for (i = 0; i < 40; i++)
49                 if (*hex++ != '0')
50                         return 0;
51         return 1;
52 }
53
54 static int verify_old_ref(const char *name, char *hex_contents)
55 {
56         int fd, ret;
57         char buffer[60];
58
59         if (is_all_zeroes(hex_contents))
60                 return 0;
61         fd = open(name, O_RDONLY);
62         if (fd < 0)
63                 return -1;
64         ret = read(fd, buffer, 40);
65         close(fd);
66         if (ret != 40)
67                 return -1;
68         if (memcmp(buffer, hex_contents, 40))
69                 return -1;
70         return 0;
71 }
72
73 static char update_hook[] = "hooks/update";
74
75 static int run_update_hook(const char *refname,
76                            char *old_hex, char *new_hex)
77 {
78         int code;
79
80         if (access(update_hook, X_OK) < 0)
81                 return 0;
82         code = run_command(update_hook, refname, old_hex, new_hex, NULL);
83         switch (code) {
84         case 0:
85                 return 0;
86         case -ERR_RUN_COMMAND_FORK:
87                 return error("hook fork failed");
88         case -ERR_RUN_COMMAND_EXEC:
89                 return error("hook execute failed");
90         case -ERR_RUN_COMMAND_WAITPID:
91                 return error("waitpid failed");
92         case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
93                 return error("waitpid is confused");
94         case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
95                 return error("%s died of signal", update_hook);
96         case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
97                 return error("%s died strangely", update_hook);
98         default:
99                 error("%s exited with error code %d", update_hook, -code);
100                 return -code;
101         }
102 }
103
104 static int update(struct command *cmd)
105 {
106         const char *name = cmd->ref_name;
107         unsigned char *old_sha1 = cmd->old_sha1;
108         unsigned char *new_sha1 = cmd->new_sha1;
109         char new_hex[60], *old_hex, *lock_name;
110         int newfd, namelen, written;
111
112         cmd->error_string = NULL;
113         if (!strncmp(name, "refs/", 5) && check_ref_format(name + 5)) {
114                 cmd->error_string = "funny refname";
115                 return error("refusing to create funny ref '%s' locally",
116                              name);
117         }
118
119         namelen = strlen(name);
120         lock_name = xmalloc(namelen + 10);
121         memcpy(lock_name, name, namelen);
122         memcpy(lock_name + namelen, ".lock", 6);
123
124         strcpy(new_hex, sha1_to_hex(new_sha1));
125         old_hex = sha1_to_hex(old_sha1);
126         if (!has_sha1_file(new_sha1)) {
127                 cmd->error_string = "bad pack";
128                 return error("unpack should have generated %s, "
129                              "but I can't find it!", new_hex);
130         }
131         safe_create_leading_directories(lock_name);
132
133         newfd = open(lock_name, O_CREAT | O_EXCL | O_WRONLY, 0666);
134         if (newfd < 0) {
135                 cmd->error_string = "can't lock";
136                 return error("unable to create %s (%s)",
137                              lock_name, strerror(errno));
138         }
139
140         /* Write the ref with an ending '\n' */
141         new_hex[40] = '\n';
142         new_hex[41] = 0;
143         written = write(newfd, new_hex, 41);
144         /* Remove the '\n' again */
145         new_hex[40] = 0;
146
147         close(newfd);
148         if (written != 41) {
149                 unlink(lock_name);
150                 cmd->error_string = "can't write";
151                 return error("unable to write %s", lock_name);
152         }
153         if (verify_old_ref(name, old_hex) < 0) {
154                 unlink(lock_name);
155                 cmd->error_string = "raced";
156                 return error("%s changed during push", name);
157         }
158         if (run_update_hook(name, old_hex, new_hex)) {
159                 unlink(lock_name);
160                 cmd->error_string = "hook declined";
161                 return error("hook declined to update %s", name);
162         }
163         else if (rename(lock_name, name) < 0) {
164                 unlink(lock_name);
165                 cmd->error_string = "can't rename";
166                 return error("unable to replace %s", name);
167         }
168         else {
169                 fprintf(stderr, "%s: %s -> %s\n", name, old_hex, new_hex);
170                 return 0;
171         }
172 }
173
174 static char update_post_hook[] = "hooks/post-update";
175
176 static void run_update_post_hook(struct command *cmd)
177 {
178         struct command *cmd_p;
179         int argc;
180         char **argv;
181
182         if (access(update_post_hook, X_OK) < 0)
183                 return;
184         for (argc = 1, cmd_p = cmd; cmd_p; cmd_p = cmd_p->next) {
185                 if (cmd_p->error_string)
186                         continue;
187                 argc++;
188         }
189         argv = xmalloc(sizeof(*argv) * (1 + argc));
190         argv[0] = update_post_hook;
191
192         for (argc = 1, cmd_p = cmd; cmd_p; cmd_p = cmd_p->next) {
193                 if (cmd_p->error_string)
194                         continue;
195                 argv[argc] = xmalloc(strlen(cmd_p->ref_name) + 1);
196                 strcpy(argv[argc], cmd_p->ref_name);
197                 argc++;
198         }
199         argv[argc] = NULL;
200         run_command_v_opt(argc, argv, RUN_COMMAND_NO_STDIO);
201 }
202
203 /*
204  * This gets called after(if) we've successfully
205  * unpacked the data payload.
206  */
207 static void execute_commands(void)
208 {
209         struct command *cmd = commands;
210
211         while (cmd) {
212                 update(cmd);
213                 cmd = cmd->next;
214         }
215         run_update_post_hook(commands);
216 }
217
218 static void read_head_info(void)
219 {
220         struct command **p = &commands;
221         for (;;) {
222                 static char line[1000];
223                 unsigned char old_sha1[20], new_sha1[20];
224                 struct command *cmd;
225                 char *refname;
226                 int len, reflen;
227
228                 len = packet_read_line(0, line, sizeof(line));
229                 if (!len)
230                         break;
231                 if (line[len-1] == '\n')
232                         line[--len] = 0;
233                 if (len < 83 ||
234                     line[40] != ' ' ||
235                     line[81] != ' ' ||
236                     get_sha1_hex(line, old_sha1) ||
237                     get_sha1_hex(line + 41, new_sha1))
238                         die("protocol error: expected old/new/ref, got '%s'",
239                             line);
240
241                 refname = line + 82;
242                 reflen = strlen(refname);
243                 if (reflen + 82 < len) {
244                         if (strstr(refname + reflen + 1, "report-status"))
245                                 report_status = 1;
246                 }
247                 cmd = xmalloc(sizeof(struct command) + len - 80);
248                 memcpy(cmd->old_sha1, old_sha1, 20);
249                 memcpy(cmd->new_sha1, new_sha1, 20);
250                 memcpy(cmd->ref_name, line + 82, len - 81);
251                 cmd->error_string = "n/a (unpacker error)";
252                 cmd->next = NULL;
253                 *p = cmd;
254                 p = &cmd->next;
255         }
256 }
257
258 static const char *unpack(int *error_code)
259 {
260         int code = run_command_v_opt(1, unpacker, RUN_GIT_CMD);
261
262         *error_code = 0;
263         switch (code) {
264         case 0:
265                 return NULL;
266         case -ERR_RUN_COMMAND_FORK:
267                 return "unpack fork failed";
268         case -ERR_RUN_COMMAND_EXEC:
269                 return "unpack execute failed";
270         case -ERR_RUN_COMMAND_WAITPID:
271                 return "waitpid failed";
272         case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
273                 return "waitpid is confused";
274         case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
275                 return "unpacker died of signal";
276         case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
277                 return "unpacker died strangely";
278         default:
279                 *error_code = -code;
280                 return "unpacker exited with error code";
281         }
282 }
283
284 static void report(const char *unpack_status)
285 {
286         struct command *cmd;
287         packet_write(1, "unpack %s\n",
288                      unpack_status ? unpack_status : "ok");
289         for (cmd = commands; cmd; cmd = cmd->next) {
290                 if (!cmd->error_string)
291                         packet_write(1, "ok %s\n",
292                                      cmd->ref_name);
293                 else
294                         packet_write(1, "ng %s %s\n",
295                                      cmd->ref_name, cmd->error_string);
296         }
297         packet_flush(1);
298 }
299
300 int main(int argc, char **argv)
301 {
302         int i;
303         char *dir = NULL;
304
305         argv++;
306         for (i = 1; i < argc; i++) {
307                 char *arg = *argv++;
308
309                 if (*arg == '-') {
310                         /* Do flag handling here */
311                         usage(receive_pack_usage);
312                 }
313                 if (dir)
314                         usage(receive_pack_usage);
315                 dir = arg;
316         }
317         if (!dir)
318                 usage(receive_pack_usage);
319
320         if(!enter_repo(dir, 0))
321                 die("'%s': unable to chdir or not a git archive", dir);
322
323         write_head_info();
324
325         /* EOF */
326         packet_flush(1);
327
328         read_head_info();
329         if (commands) {
330                 int code;
331                 const char *unpack_status = unpack(&code);
332                 if (!unpack_status)
333                         execute_commands();
334                 if (report_status)
335                         report(unpack_status);
336         }
337         return 0;
338 }