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("%s", 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         /* Upload-pack must report HEAD first */
  55         if (!strcmp(ref->name, "HEAD")) {
  56                 head = ref;
  57                 ref = ref->next;
  58         }
  59         head_ptr = NULL;
  60         master_ref = NULL;
  61         while (ref) {
  62                 if (is_master(ref))
  63                         master_ref = ref;
  64                 if (head &&
  65                     !memcmp(ref->old_sha1, head->old_sha1, 20) &&
  66                     !strncmp(ref->name, "refs/heads/",11) &&
  67                     (!head_ptr || ref == master_ref))
  68                         head_ptr = ref;
  69
  70                 write_one_ref(ref);
  71                 ref = ref->next;
  72         }
  73         if (!head) {
  74                 fprintf(stderr, "No HEAD in remote.\n");
  75                 return;
  76         }
  77
  78         head_path = strdup(git_path("HEAD"));
  79         if (!head_ptr) {
  80                 /*
  81                  * If we had a master ref, and it wasn't HEAD, we need to undo the
  82                  * symlink, and write a standalone HEAD. Give a warning, because that's
  83                  * really really wrong.
  84                  */
  85                 if (master_ref) {
  86                         error("HEAD doesn't point to any refs! Making standalone HEAD");
  87                         unlink(head_path);
  88                 }
  89                 write_one_ref(head);
  90                 free(head_path);
  91                 return;
  92         }
  93
  94         /* We reset to the master branch if it's available */
  95         if (master_ref)
  96                 return;
  97
  98         fprintf(stderr, "Setting HEAD to %s\n", head_ptr->name);
  99
 100         /*
 101          * Uhhuh. Other end didn't have master. We start HEAD off with
 102          * the first branch with the same value.
 103          */
 104         if (create_symref(head_path, head_ptr->name) < 0)
 105                 die("unable to link HEAD to %s", head_ptr->name);
 106         free(head_path);
 107 }
 108
 109 static int clone_pack(int fd[2], int nr_match, char **match)
 110 {
 111         struct ref *refs;
 112         int status;
 113         pid_t pid;
 114
 115         get_remote_heads(fd[0], &refs, nr_match, match);
 116         if (!refs) {
 117                 packet_flush(fd[1]);
 118                 die("no matching remote head");
 119         }
 120         clone_handshake(fd, refs);
 121         pid = fork();
 122         if (pid < 0)
 123                 die("git-clone-pack: unable to fork off git-unpack-objects");
 124         if (!pid) {
 125                 dup2(fd[0], 0);
 126                 close(fd[0]);
 127                 close(fd[1]);
 128                 execlp("git-unpack-objects", "git-unpack-objects",
 129                         quiet ? "-q" : NULL, NULL);
 130                 die("git-unpack-objects exec failed");
 131         }
 132         close(fd[0]);
 133         close(fd[1]);
 134         while (waitpid(pid, &status, 0) < 0) {
 135                 if (errno != EINTR)
 136                         die("waiting for git-unpack-objects: %s", strerror(errno));
 137         }
 138         if (WIFEXITED(status)) {
 139                 int code = WEXITSTATUS(status);
 140                 if (code)
 141                         die("git-unpack-objects died with error code %d", code);
 142                 write_refs(refs);
 143                 return 0;
 144         }
 145         if (WIFSIGNALED(status)) {
 146                 int sig = WTERMSIG(status);
 147                 die("git-unpack-objects died of signal %d", sig);
 148         }
 149         die("Sherlock Holmes! git-unpack-objects died of unnatural causes %d!", status);
 150 }
 151
 152 int main(int argc, char **argv)
 153 {
 154         int i, ret, nr_heads;
 155         char *dest = NULL, **heads;
 156         int fd[2];
 157         pid_t pid;
 158
 159         nr_heads = 0;
 160         heads = NULL;
 161         for (i = 1; i < argc; i++) {
 162                 char *arg = argv[i];
 163
 164                 if (*arg == '-') {
 165                         if (!strcmp("-q", arg)) {
 166                                 quiet = 1;
 167                                 continue;
 168                         }
 169                         if (!strncmp("--exec=", arg, 7)) {
 170                                 exec = arg + 7;
 171                                 continue;
 172                         }
 173                         usage(clone_pack_usage);
 174                 }
 175                 dest = arg;
 176                 heads = argv + i + 1;
 177                 nr_heads = argc - i - 1;
 178                 break;
 179         }
 180         if (!dest)
 181                 usage(clone_pack_usage);
 182         pid = git_connect(fd, dest, exec);
 183         if (pid < 0)
 184                 return 1;
 185         ret = clone_pack(fd, nr_heads, heads);
 186         close(fd[0]);
 187         close(fd[1]);
 188         finish_connect(pid);
 189         return ret;
 190 }