[PATCH] GIT: Try all addresses for given remote name
[git] / clone-pack.c
1 #include "cache.h"
2 #include "refs.h"
3 #include "pkt-line.h"
4 #include <sys/wait.h>
5
6 static int quiet;
7 static const char clone_pack_usage[] = "git-clone-pack [-q] [--exec=<git-upload-pack>] [<host>:]<directory> [<heads>]*";
8 static const char *exec = "git-upload-pack";
9
10 static void clone_handshake(int fd[2], struct ref *ref)
11 {
12         unsigned char sha1[20];
13
14         while (ref) {
15                 packet_write(fd[1], "want %s\n", sha1_to_hex(ref->old_sha1));
16                 ref = ref->next;
17         }
18         packet_flush(fd[1]);
19
20         /* We don't have nuttin' */
21         packet_write(fd[1], "done\n");
22         if (get_ack(fd[0], sha1))
23                 error("Huh! git-clone-pack got positive ack for %s", sha1_to_hex(sha1));
24 }
25
26 static int is_master(struct ref *ref)
27 {
28         return !strcmp(ref->name, "refs/heads/master");
29 }
30
31 static void write_one_ref(struct ref *ref)
32 {
33         char *path = git_path(ref->name);
34         int fd;
35         char *hex;
36
37         if (safe_create_leading_directories(path))
38                 die("unable to create leading directory for %s", ref->name);
39         fd = open(path, O_CREAT | O_EXCL | O_WRONLY, 0666);
40         if (fd < 0)
41                 die("unable to create ref %s", ref->name);
42         hex = sha1_to_hex(ref->old_sha1);
43         hex[40] = '\n';
44         if (write(fd, hex, 41) != 41)
45                 die("unable to write ref %s", ref->name);
46         close(fd);
47 }
48
49 static void write_refs(struct ref *ref)
50 {
51         struct ref *head = NULL, *head_ptr, *master_ref;
52         char *head_path;
53
54         if (!strcmp(ref->name, "HEAD")) {
55                 head = ref;
56                 ref = ref->next;
57         }
58         head_ptr = NULL;
59         master_ref = NULL;
60         while (ref) {
61                 if (is_master(ref))
62                         master_ref = ref;
63                 if (head && !memcmp(ref->old_sha1, head->old_sha1, 20)) {
64                         if (!head_ptr || ref == master_ref)
65                                 head_ptr = ref;
66                 }
67                 write_one_ref(ref);
68                 ref = ref->next;
69         }
70         if (!head)
71                 return;
72
73         head_path = git_path("HEAD");
74         if (!head_ptr) {
75                 /*
76                  * If we had a master ref, and it wasn't HEAD, we need to undo the
77                  * symlink, and write a standalone HEAD. Give a warning, because that's
78                  * really really wrong.
79                  */
80                 if (master_ref) {
81                         error("HEAD doesn't point to any refs! Making standalone HEAD");
82                         unlink(head_path);
83                 }
84                 write_one_ref(head);
85                 return;
86         }
87
88         /* We reset to the master branch if it's available */
89         if (master_ref)
90                 return;
91
92         /*
93          * Uhhuh. Other end didn't have master. We start HEAD off with
94          * the first branch with the same value.
95          */
96         unlink(head_path);
97         if (symlink(head_ptr->name, head_path) < 0)
98                 die("unable to link HEAD to %s", head_ptr->name);
99 }
100
101 static int clone_pack(int fd[2], int nr_match, char **match)
102 {
103         struct ref *refs;
104         int status;
105         pid_t pid;
106
107         get_remote_heads(fd[0], &refs, nr_match, match);
108         if (!refs) {
109                 packet_flush(fd[1]);
110                 die("no matching remote head");
111         }
112         clone_handshake(fd, refs);
113         pid = fork();
114         if (pid < 0)
115                 die("git-clone-pack: unable to fork off git-unpack-objects");
116         if (!pid) {
117                 dup2(fd[0], 0);
118                 close(fd[0]);
119                 close(fd[1]);
120                 execlp("git-unpack-objects", "git-unpack-objects",
121                         quiet ? "-q" : NULL, NULL);
122                 die("git-unpack-objects exec failed");
123         }
124         close(fd[0]);
125         close(fd[1]);
126         while (waitpid(pid, &status, 0) < 0) {
127                 if (errno != EINTR)
128                         die("waiting for git-unpack-objects: %s", strerror(errno));
129         }
130         if (WIFEXITED(status)) {
131                 int code = WEXITSTATUS(status);
132                 if (code)
133                         die("git-unpack-objects died with error code %d", code);
134                 write_refs(refs);
135                 return 0;
136         }
137         if (WIFSIGNALED(status)) {
138                 int sig = WTERMSIG(status);
139                 die("git-unpack-objects died of signal %d", sig);
140         }
141         die("Sherlock Holmes! git-unpack-objects died of unnatural causes %d!", status);
142 }
143
144 int main(int argc, char **argv)
145 {
146         int i, ret, nr_heads;
147         char *dest = NULL, **heads;
148         int fd[2];
149         pid_t pid;
150
151         nr_heads = 0;
152         heads = NULL;
153         for (i = 1; i < argc; i++) {
154                 char *arg = argv[i];
155
156                 if (*arg == '-') {
157                         if (!strcmp("-q", arg)) {
158                                 quiet = 1;
159                                 continue;
160                         }
161                         if (!strncmp("--exec=", arg, 7)) {
162                                 exec = arg + 7;
163                                 continue;
164                         }
165                         usage(clone_pack_usage);
166                 }
167                 dest = arg;
168                 heads = argv + i + 1;
169                 nr_heads = argc - i - 1;
170                 break;
171         }
172         if (!dest)
173                 usage(clone_pack_usage);
174         pid = git_connect(fd, dest, exec);
175         if (pid < 0)
176                 return 1;
177         ret = clone_pack(fd, nr_heads, heads);
178         close(fd[0]);
179         close(fd[1]);
180         finish_connect(pid);
181         return ret;
182 }