Be careful when dereferencing tags.
[git/git.git] / send-pack.c
1 #include "cache.h"
2 #include "commit.h"
3 #include "tag.h"
4 #include "refs.h"
5 #include "pkt-line.h"
6
7 static const char send_pack_usage[] =
8 "git-send-pack [--all] [--exec=git-receive-pack] <remote> [<head>...]\n"
9 " --all and explicit <head> specification are mutually exclusive.";
10 static const char *exec = "git-receive-pack";
11 static int send_all = 0;
12 static int force_update = 0;
13
14 static int is_zero_sha1(const unsigned char *sha1)
15 {
16 int i;
17
18 for (i = 0; i < 20; i++) {
19 if (*sha1++)
20 return 0;
21 }
22 return 1;
23 }
24
25 static void exec_pack_objects(void)
26 {
27 static char *args[] = {
28 "git-pack-objects",
29 "--stdout",
30 NULL
31 };
32 execvp("git-pack-objects", args);
33 die("git-pack-objects exec failed (%s)", strerror(errno));
34 }
35
36 static void exec_rev_list(struct ref *refs)
37 {
38 static char *args[1000];
39 int i = 0;
40
41 args[i++] = "git-rev-list"; /* 0 */
42 args[i++] = "--objects"; /* 1 */
43 while (refs) {
44 char *buf = malloc(100);
45 if (i > 900)
46 die("git-rev-list environment overflow");
47 if (!is_zero_sha1(refs->old_sha1) &&
48 has_sha1_file(refs->old_sha1)) {
49 args[i++] = buf;
50 snprintf(buf, 50, "^%s", sha1_to_hex(refs->old_sha1));
51 buf += 50;
52 }
53 if (!is_zero_sha1(refs->new_sha1)) {
54 args[i++] = buf;
55 snprintf(buf, 50, "%s", sha1_to_hex(refs->new_sha1));
56 }
57 refs = refs->next;
58 }
59 args[i] = NULL;
60 execvp("git-rev-list", args);
61 die("git-rev-list exec failed (%s)", strerror(errno));
62 }
63
64 static void rev_list(int fd, struct ref *refs)
65 {
66 int pipe_fd[2];
67 pid_t pack_objects_pid;
68
69 if (pipe(pipe_fd) < 0)
70 die("rev-list setup: pipe failed");
71 pack_objects_pid = fork();
72 if (!pack_objects_pid) {
73 dup2(pipe_fd[0], 0);
74 dup2(fd, 1);
75 close(pipe_fd[0]);
76 close(pipe_fd[1]);
77 close(fd);
78 exec_pack_objects();
79 die("pack-objects setup failed");
80 }
81 if (pack_objects_pid < 0)
82 die("pack-objects fork failed");
83 dup2(pipe_fd[1], 1);
84 close(pipe_fd[0]);
85 close(pipe_fd[1]);
86 close(fd);
87 exec_rev_list(refs);
88 }
89
90 static int pack_objects(int fd, struct ref *refs)
91 {
92 pid_t rev_list_pid;
93
94 rev_list_pid = fork();
95 if (!rev_list_pid) {
96 rev_list(fd, refs);
97 die("rev-list setup failed");
98 }
99 if (rev_list_pid < 0)
100 die("rev-list fork failed");
101 /*
102 * We don't wait for the rev-list pipeline in the parent:
103 * we end up waiting for the other end instead
104 */
105 return 0;
106 }
107
108 static void unmark_and_free(struct commit_list *list, unsigned int mark)
109 {
110 while (list) {
111 struct commit_list *temp = list;
112 temp->item->object.flags &= ~mark;
113 list = temp->next;
114 free(temp);
115 }
116 }
117
118 static int ref_newer(const unsigned char *new_sha1,
119 const unsigned char *old_sha1)
120 {
121 struct object *o;
122 struct commit *old, *new;
123 struct commit_list *list, *used;
124 int found = 0;
125
126 /* Both new and old must be commit-ish and new is descendant of
127 * old. Otherwise we require --force.
128 */
129 o = deref_tag(parse_object(old_sha1), NULL, 0);
130 if (!o || o->type != commit_type)
131 return 0;
132 old = (struct commit *) o;
133
134 o = deref_tag(parse_object(new_sha1), NULL, 0);
135 if (!o || o->type != commit_type)
136 return 0;
137 new = (struct commit *) o;
138
139 if (parse_commit(new) < 0)
140 return 0;
141
142 used = list = NULL;
143 commit_list_insert(new, &list);
144 while (list) {
145 new = pop_most_recent_commit(&list, 1);
146 commit_list_insert(new, &used);
147 if (new == old) {
148 found = 1;
149 break;
150 }
151 }
152 unmark_and_free(list, 1);
153 unmark_and_free(used, 1);
154 return found;
155 }
156
157 static struct ref *local_refs, **local_tail;
158 static struct ref *remote_refs, **remote_tail;
159
160 static int one_local_ref(const char *refname, const unsigned char *sha1)
161 {
162 struct ref *ref;
163 int len = strlen(refname) + 1;
164 ref = xcalloc(1, sizeof(*ref) + len);
165 memcpy(ref->new_sha1, sha1, 20);
166 memcpy(ref->name, refname, len);
167 *local_tail = ref;
168 local_tail = &ref->next;
169 return 0;
170 }
171
172 static void get_local_heads(void)
173 {
174 local_tail = &local_refs;
175 for_each_ref(one_local_ref);
176 }
177
178 static int send_pack(int in, int out, int nr_refspec, char **refspec)
179 {
180 struct ref *ref;
181 int new_refs;
182
183 /* No funny business with the matcher */
184 remote_tail = get_remote_heads(in, &remote_refs, 0, NULL, 1);
185 get_local_heads();
186
187 /* match them up */
188 if (!remote_tail)
189 remote_tail = &remote_refs;
190 if (match_refs(local_refs, remote_refs, &remote_tail,
191 nr_refspec, refspec, send_all))
192 return -1;
193 /*
194 * Finally, tell the other end!
195 */
196 new_refs = 0;
197 for (ref = remote_refs; ref; ref = ref->next) {
198 char old_hex[60], *new_hex;
199 if (!ref->peer_ref)
200 continue;
201 if (!memcmp(ref->old_sha1, ref->peer_ref->new_sha1, 20)) {
202 fprintf(stderr, "'%s': up-to-date\n", ref->name);
203 continue;
204 }
205
206 /* This part determines what can overwrite what.
207 * The rules are:
208 *
209 * (0) you can always use --force or +A:B notation to
210 * selectively force individual ref pairs.
211 *
212 * (1) if the old thing does not exist, it is OK.
213 *
214 * (2) if you do not have the old thing, you are not allowed
215 * to overwrite it; you would not know what you are losing
216 * otherwise.
217 *
218 * (3) if both new and old are commit-ish, and new is a
219 * descendant of old, it is OK.
220 */
221
222 if (!force_update &&
223 !is_zero_sha1(ref->old_sha1) &&
224 !ref->force) {
225 if (!has_sha1_file(ref->old_sha1)) {
226 error("remote '%s' object %s does not "
227 "exist on local",
228 ref->name, sha1_to_hex(ref->old_sha1));
229 continue;
230 }
231
232 /* We assume that local is fsck-clean. Otherwise
233 * you _could_ have an old tag which points at
234 * something you do not have, which may or may not
235 * be a commit.
236 */
237 if (!ref_newer(ref->peer_ref->new_sha1,
238 ref->old_sha1)) {
239 error("remote ref '%s' is not a strict "
240 "subset of local ref '%s'.", ref->name,
241 ref->peer_ref->name);
242 continue;
243 }
244 }
245 memcpy(ref->new_sha1, ref->peer_ref->new_sha1, 20);
246 if (is_zero_sha1(ref->new_sha1)) {
247 error("cannot happen anymore");
248 continue;
249 }
250 new_refs++;
251 strcpy(old_hex, sha1_to_hex(ref->old_sha1));
252 new_hex = sha1_to_hex(ref->new_sha1);
253 packet_write(out, "%s %s %s", old_hex, new_hex, ref->name);
254 fprintf(stderr, "updating '%s'", ref->name);
255 if (strcmp(ref->name, ref->peer_ref->name))
256 fprintf(stderr, " using '%s'", ref->peer_ref->name);
257 fprintf(stderr, "\n from %s\n to %s\n", old_hex, new_hex);
258 }
259
260 packet_flush(out);
261 if (new_refs)
262 pack_objects(out, remote_refs);
263 close(out);
264 return 0;
265 }
266
267
268 int main(int argc, char **argv)
269 {
270 int i, nr_heads = 0;
271 char *dest = NULL;
272 char **heads = NULL;
273 int fd[2], ret;
274 pid_t pid;
275
276 argv++;
277 for (i = 1; i < argc; i++, argv++) {
278 char *arg = *argv;
279
280 if (*arg == '-') {
281 if (!strncmp(arg, "--exec=", 7)) {
282 exec = arg + 7;
283 continue;
284 }
285 if (!strcmp(arg, "--all")) {
286 send_all = 1;
287 continue;
288 }
289 if (!strcmp(arg, "--force")) {
290 force_update = 1;
291 continue;
292 }
293 usage(send_pack_usage);
294 }
295 if (!dest) {
296 dest = arg;
297 continue;
298 }
299 heads = argv;
300 nr_heads = argc - i;
301 break;
302 }
303 if (!dest)
304 usage(send_pack_usage);
305 if (heads && send_all)
306 usage(send_pack_usage);
307 pid = git_connect(fd, dest, exec);
308 if (pid < 0)
309 return 1;
310 ret = send_pack(fd[0], fd[1], nr_heads, heads);
311 close(fd[0]);
312 close(fd[1]);
313 finish_connect(pid);
314 return ret;
315 }