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 }