Exec git programs without using PATH.
[git/git.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\n", 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\n", 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 }