clone-pack.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "pkt-line.h"
   4 #include <sys/wait.h>
   5
   6 static const char clone_pack_usage[] =
   7 "git-clone-pack [--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 finish_pack(const char *pack_tmp_name)
 116 {
 117         int pipe_fd[2];
 118         pid_t pid;
 119         char idx[PATH_MAX];
 120         char final[PATH_MAX];
 121         char hash[41];
 122         unsigned char sha1[20];
 123         char *cp;
 124         int err = 0;
 125
 126         if (pipe(pipe_fd) < 0)
 127                 die("git-clone-pack: unable to set up pipe");
 128
 129         strcpy(idx, pack_tmp_name); /* ".git/objects/pack-XXXXXX" */
 130         cp = strrchr(idx, '/');
 131         memcpy(cp, "/pidx", 5);
 132
 133         pid = fork();
 134         if (pid < 0)
 135                 die("git-clone-pack: unable to fork off git-index-pack");
 136         if (!pid) {
 137                 close(0);
 138                 dup2(pipe_fd[1], 1);
 139                 close(pipe_fd[0]);
 140                 close(pipe_fd[1]);
 141                 execlp("git-index-pack","git-index-pack",
 142                        "-o", idx, pack_tmp_name, NULL);
 143                 error("cannot exec git-index-pack <%s> <%s>",
 144                       idx, pack_tmp_name);
 145                 exit(1);
 146         }
 147         close(pipe_fd[1]);
 148         if (read(pipe_fd[0], hash, 40) != 40) {
 149                 error("git-clone-pack: unable to read from git-index-pack");
 150                 err = 1;
 151         }
 152         close(pipe_fd[0]);
 153
 154         for (;;) {
 155                 int status, code;
 156                 int retval = waitpid(pid, &status, 0);
 157
 158                 if (retval < 0) {
 159                         if (errno == EINTR)
 160                                 continue;
 161                         error("waitpid failed (%s)", strerror(retval));
 162                         goto error_die;
 163                 }
 164                 if (WIFSIGNALED(status)) {
 165                         int sig = WTERMSIG(status);
 166                         error("git-index-pack died of signal %d", sig);
 167                         goto error_die;
 168                 }
 169                 if (!WIFEXITED(status)) {
 170                         error("git-index-pack died of unnatural causes %d",
 171                               status);
 172                         goto error_die;
 173                 }
 174                 code = WEXITSTATUS(status);
 175                 if (code) {
 176                         error("git-index-pack died with error code %d", code);
 177                         goto error_die;
 178                 }
 179                 if (err)
 180                         goto error_die;
 181                 break;
 182         }
 183         hash[40] = 0;
 184         if (get_sha1_hex(hash, sha1)) {
 185                 error("git-index-pack reported nonsense '%s'", hash);
 186                 goto error_die;
 187         }
 188         /* Now we have pack in pack_tmp_name[], and
 189          * idx in idx[]; rename them to their final names.
 190          */
 191         snprintf(final, sizeof(final),
 192                  "%s/pack/pack-%s.pack", get_object_directory(), hash);
 193         move_temp_to_file(pack_tmp_name, final);
 194         chmod(final, 0444);
 195         snprintf(final, sizeof(final),
 196                  "%s/pack/pack-%s.idx", get_object_directory(), hash);
 197         move_temp_to_file(idx, final);
 198         chmod(final, 0444);
 199         return 0;
 200
 201  error_die:
 202         unlink(idx);
 203         unlink(pack_tmp_name);
 204         exit(1);
 205 }
 206
 207 static int clone_without_unpack(int fd[2])
 208 {
 209         char tmpfile[PATH_MAX];
 210         int ofd, ifd;
 211
 212         ifd = fd[0];
 213         snprintf(tmpfile, sizeof(tmpfile),
 214                  "%s/pack/tmp-XXXXXX", get_object_directory());
 215         ofd = mkstemp(tmpfile);
 216         if (ofd < 0)
 217                 return error("unable to create temporary file %s", tmpfile);
 218
 219         while (1) {
 220                 char buf[8192];
 221                 ssize_t sz, wsz, pos;
 222                 sz = read(ifd, buf, sizeof(buf));
 223                 if (sz == 0)
 224                         break;
 225                 if (sz < 0) {
 226                         error("error reading pack (%s)", strerror(errno));
 227                         close(ofd);
 228                         unlink(tmpfile);
 229                         return -1;
 230                 }
 231                 pos = 0;
 232                 while (pos < sz) {
 233                         wsz = write(ofd, buf + pos, sz - pos);
 234                         if (wsz < 0) {
 235                                 error("error writing pack (%s)",
 236                                       strerror(errno));
 237                                 close(ofd);
 238                                 unlink(tmpfile);
 239                                 return -1;
 240                         }
 241                         pos += wsz;
 242                 }
 243         }
 244         close(ofd);
 245         return finish_pack(tmpfile);
 246 }
 247
 248 static int clone_pack(int fd[2], int nr_match, char **match)
 249 {
 250         struct ref *refs;
 251         int status;
 252
 253         get_remote_heads(fd[0], &refs, nr_match, match, 1);
 254         if (!refs) {
 255                 packet_flush(fd[1]);
 256                 die("no matching remote head");
 257         }
 258         clone_handshake(fd, refs);
 259
 260         status = clone_without_unpack(fd);
 261
 262         if (!status)
 263                 write_refs(refs);
 264         return status;
 265 }
 266
 267 int main(int argc, char **argv)
 268 {
 269         int i, ret, nr_heads;
 270         char *dest = NULL, **heads;
 271         int fd[2];
 272         pid_t pid;
 273
 274         nr_heads = 0;
 275         heads = NULL;
 276         for (i = 1; i < argc; i++) {
 277                 char *arg = argv[i];
 278
 279                 if (*arg == '-') {
 280                         if (!strcmp("-q", arg))
 281                                 continue;
 282                         if (!strncmp("--exec=", arg, 7)) {
 283                                 exec = arg + 7;
 284                                 continue;
 285                         }
 286                         if (!strcmp("--keep", arg))
 287                                 continue;
 288                         usage(clone_pack_usage);
 289                 }
 290                 dest = arg;
 291                 heads = argv + i + 1;
 292                 nr_heads = argc - i - 1;
 293                 break;
 294         }
 295         if (!dest)
 296                 usage(clone_pack_usage);
 297         pid = git_connect(fd, dest, exec);
 298         if (pid < 0)
 299                 return 1;
 300         ret = clone_pack(fd, nr_heads, heads);
 301         close(fd[0]);
 302         close(fd[1]);
 303         finish_connect(pid);
 304         return ret;
 305 }