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 (!strncmp(ref->name, "refs/", 5) &&
  38             check_ref_format(ref->name + 5)) {
  39                 error("refusing to create funny ref '%s' locally", ref->name);
  40                 return;
  41         }
  42
  43         if (safe_create_leading_directories(path))
  44                 die("unable to create leading directory for %s", ref->name);
  45         fd = open(path, O_CREAT | O_EXCL | O_WRONLY, 0666);
  46         if (fd < 0)
  47                 die("unable to create ref %s", ref->name);
  48         hex = sha1_to_hex(ref->old_sha1);
  49         hex[40] = '\n';
  50         if (write(fd, hex, 41) != 41)
  51                 die("unable to write ref %s", ref->name);
  52         close(fd);
  53 }
  54
  55 static void write_refs(struct ref *ref)
  56 {
  57         struct ref *head = NULL, *head_ptr, *master_ref;
  58         char *head_path;
  59
  60         /* Upload-pack must report HEAD first */
  61         if (!strcmp(ref->name, "HEAD")) {
  62                 head = ref;
  63                 ref = ref->next;
  64         }
  65         head_ptr = NULL;
  66         master_ref = NULL;
  67         while (ref) {
  68                 if (is_master(ref))
  69                         master_ref = ref;
  70                 if (head &&
  71                     !memcmp(ref->old_sha1, head->old_sha1, 20) &&
  72                     !strncmp(ref->name, "refs/heads/",11) &&
  73                     (!head_ptr || ref == master_ref))
  74                         head_ptr = ref;
  75
  76                 write_one_ref(ref);
  77                 ref = ref->next;
  78         }
  79         if (!head) {
  80                 fprintf(stderr, "No HEAD in remote.\n");
  81                 return;
  82         }
  83
  84         head_path = strdup(git_path("HEAD"));
  85         if (!head_ptr) {
  86                 /*
  87                  * If we had a master ref, and it wasn't HEAD, we need to undo the
  88                  * symlink, and write a standalone HEAD. Give a warning, because that's
  89                  * really really wrong.
  90                  */
  91                 if (master_ref) {
  92                         error("HEAD doesn't point to any refs! Making standalone HEAD");
  93                         unlink(head_path);
  94                 }
  95                 write_one_ref(head);
  96                 free(head_path);
  97                 return;
  98         }
  99
 100         /* We reset to the master branch if it's available */
 101         if (master_ref)
 102                 return;
 103
 104         fprintf(stderr, "Setting HEAD to %s\n", head_ptr->name);
 105
 106         /*
 107          * Uhhuh. Other end didn't have master. We start HEAD off with
 108          * the first branch with the same value.
 109          */
 110         if (create_symref(head_path, head_ptr->name) < 0)
 111                 die("unable to link HEAD to %s", head_ptr->name);
 112         free(head_path);
 113 }
 114
 115 static int clone_pack(int fd[2], int nr_match, char **match)
 116 {
 117         struct ref *refs;
 118         int status;
 119         pid_t pid;
 120
 121         get_remote_heads(fd[0], &refs, nr_match, match, 1);
 122         if (!refs) {
 123                 packet_flush(fd[1]);
 124                 die("no matching remote head");
 125         }
 126         clone_handshake(fd, refs);
 127         pid = fork();
 128         if (pid < 0)
 129                 die("git-clone-pack: unable to fork off git-unpack-objects");
 130         if (!pid) {
 131                 dup2(fd[0], 0);
 132                 close(fd[0]);
 133                 close(fd[1]);
 134                 execlp("git-unpack-objects", "git-unpack-objects",
 135                         quiet ? "-q" : NULL, NULL);
 136                 die("git-unpack-objects exec failed");
 137         }
 138         close(fd[0]);
 139         close(fd[1]);
 140         while (waitpid(pid, &status, 0) < 0) {
 141                 if (errno != EINTR)
 142                         die("waiting for git-unpack-objects: %s", strerror(errno));
 143         }
 144         if (WIFEXITED(status)) {
 145                 int code = WEXITSTATUS(status);
 146                 if (code)
 147                         die("git-unpack-objects died with error code %d", code);
 148                 write_refs(refs);
 149                 return 0;
 150         }
 151         if (WIFSIGNALED(status)) {
 152                 int sig = WTERMSIG(status);
 153                 die("git-unpack-objects died of signal %d", sig);
 154         }
 155         die("Sherlock Holmes! git-unpack-objects died of unnatural causes %d!", status);
 156 }
 157
 158 int main(int argc, char **argv)
 159 {
 160         int i, ret, nr_heads;
 161         char *dest = NULL, **heads;
 162         int fd[2];
 163         pid_t pid;
 164
 165         nr_heads = 0;
 166         heads = NULL;
 167         for (i = 1; i < argc; i++) {
 168                 char *arg = argv[i];
 169
 170                 if (*arg == '-') {
 171                         if (!strcmp("-q", arg)) {
 172                                 quiet = 1;
 173                                 continue;
 174                         }
 175                         if (!strncmp("--exec=", arg, 7)) {
 176                                 exec = arg + 7;
 177                                 continue;
 178                         }
 179                         usage(clone_pack_usage);
 180                 }
 181                 dest = arg;
 182                 heads = argv + i + 1;
 183                 nr_heads = argc - i - 1;
 184                 break;
 185         }
 186         if (!dest)
 187                 usage(clone_pack_usage);
 188         pid = git_connect(fd, dest, exec);
 189         if (pid < 0)
 190                 return 1;
 191         ret = clone_pack(fd, nr_heads, heads);
 192         close(fd[0]);
 193         close(fd[1]);
 194         finish_connect(pid);
 195         return ret;
 196 }