send-pack.c

   1 #include "cache.h"
   2 #include "commit.h"
   3 #include "tag.h"
   4 #include "refs.h"
   5 #include "pkt-line.h"
   6
   7 static const char send_pack_usage[] =
   8 "git-send-pack [--all] [--exec=git-receive-pack] <remote> [<head>...]\n"
   9 "  --all and explicit <head> specification are mutually exclusive.";
  10 static const char *exec = "git-receive-pack";
  11 static int send_all = 0;
  12 static int force_update = 0;
  13
  14 static int is_zero_sha1(const unsigned char *sha1)
  15 {
  16         int i;
  17
  18         for (i = 0; i < 20; i++) {
  19                 if (*sha1++)
  20                         return 0;
  21         }
  22         return 1;
  23 }
  24
  25 static void exec_pack_objects(void)
  26 {
  27         static char *args[] = {
  28                 "git-pack-objects",
  29                 "--stdout",
  30                 NULL
  31         };
  32         execvp("git-pack-objects", args);
  33         die("git-pack-objects exec failed (%s)", strerror(errno));
  34 }
  35
  36 static void exec_rev_list(struct ref *refs)
  37 {
  38         static char *args[1000];
  39         int i = 0;
  40
  41         args[i++] = "git-rev-list";     /* 0 */
  42         args[i++] = "--objects";        /* 1 */
  43         while (refs) {
  44                 char *buf = malloc(100);
  45                 if (i > 900)
  46                         die("git-rev-list environment overflow");
  47                 if (!is_zero_sha1(refs->old_sha1) &&
  48                     has_sha1_file(refs->old_sha1)) {
  49                         args[i++] = buf;
  50                         snprintf(buf, 50, "^%s", sha1_to_hex(refs->old_sha1));
  51                         buf += 50;
  52                 }
  53                 if (!is_zero_sha1(refs->new_sha1)) {
  54                         args[i++] = buf;
  55                         snprintf(buf, 50, "%s", sha1_to_hex(refs->new_sha1));
  56                 }
  57                 refs = refs->next;
  58         }
  59         args[i] = NULL;
  60         execvp("git-rev-list", args);
  61         die("git-rev-list exec failed (%s)", strerror(errno));
  62 }
  63
  64 static void rev_list(int fd, struct ref *refs)
  65 {
  66         int pipe_fd[2];
  67         pid_t pack_objects_pid;
  68
  69         if (pipe(pipe_fd) < 0)
  70                 die("rev-list setup: pipe failed");
  71         pack_objects_pid = fork();
  72         if (!pack_objects_pid) {
  73                 dup2(pipe_fd[0], 0);
  74                 dup2(fd, 1);
  75                 close(pipe_fd[0]);
  76                 close(pipe_fd[1]);
  77                 close(fd);
  78                 exec_pack_objects();
  79                 die("pack-objects setup failed");
  80         }
  81         if (pack_objects_pid < 0)
  82                 die("pack-objects fork failed");
  83         dup2(pipe_fd[1], 1);
  84         close(pipe_fd[0]);
  85         close(pipe_fd[1]);
  86         close(fd);
  87         exec_rev_list(refs);
  88 }
  89
  90 static int pack_objects(int fd, struct ref *refs)
  91 {
  92         pid_t rev_list_pid;
  93
  94         rev_list_pid = fork();
  95         if (!rev_list_pid) {
  96                 rev_list(fd, refs);
  97                 die("rev-list setup failed");
  98         }
  99         if (rev_list_pid < 0)
 100                 die("rev-list fork failed");
 101         /*
 102          * We don't wait for the rev-list pipeline in the parent:
 103          * we end up waiting for the other end instead
 104          */
 105         return 0;
 106 }
 107
 108 static void unmark_and_free(struct commit_list *list, unsigned int mark)
 109 {
 110         while (list) {
 111                 struct commit_list *temp = list;
 112                 temp->item->object.flags &= ~mark;
 113                 list = temp->next;
 114                 free(temp);
 115         }
 116 }
 117
 118 static int ref_newer(const unsigned char *new_sha1,
 119                      const unsigned char *old_sha1)
 120 {
 121         struct object *o;
 122         struct commit *old, *new;
 123         struct commit_list *list, *used;
 124         int found = 0;
 125
 126         /* Both new and old must be commit-ish and new is descendant of
 127          * old.  Otherwise we require --force.
 128          */
 129         o = deref_tag(parse_object(old_sha1), NULL, 0);
 130         if (!o || o->type != commit_type)
 131                 return 0;
 132         old = (struct commit *) o;
 133
 134         o = deref_tag(parse_object(new_sha1), NULL, 0);
 135         if (!o || o->type != commit_type)
 136                 return 0;
 137         new = (struct commit *) o;
 138
 139         if (parse_commit(new) < 0)
 140                 return 0;
 141
 142         used = list = NULL;
 143         commit_list_insert(new, &list);
 144         while (list) {
 145                 new = pop_most_recent_commit(&list, 1);
 146                 commit_list_insert(new, &used);
 147                 if (new == old) {
 148                         found = 1;
 149                         break;
 150                 }
 151         }
 152         unmark_and_free(list, 1);
 153         unmark_and_free(used, 1);
 154         return found;
 155 }
 156
 157 static struct ref *local_refs, **local_tail;
 158 static struct ref *remote_refs, **remote_tail;
 159
 160 static int one_local_ref(const char *refname, const unsigned char *sha1)
 161 {
 162         struct ref *ref;
 163         int len = strlen(refname) + 1;
 164         ref = xcalloc(1, sizeof(*ref) + len);
 165         memcpy(ref->new_sha1, sha1, 20);
 166         memcpy(ref->name, refname, len);
 167         *local_tail = ref;
 168         local_tail = &ref->next;
 169         return 0;
 170 }
 171
 172 static void get_local_heads(void)
 173 {
 174         local_tail = &local_refs;
 175         for_each_ref(one_local_ref);
 176 }
 177
 178 static int send_pack(int in, int out, int nr_refspec, char **refspec)
 179 {
 180         struct ref *ref;
 181         int new_refs;
 182
 183         /* No funny business with the matcher */
 184         remote_tail = get_remote_heads(in, &remote_refs, 0, NULL, 1);
 185         get_local_heads();
 186
 187         /* match them up */
 188         if (!remote_tail)
 189                 remote_tail = &remote_refs;
 190         if (match_refs(local_refs, remote_refs, &remote_tail,
 191                        nr_refspec, refspec, send_all))
 192                 return -1;
 193         /*
 194          * Finally, tell the other end!
 195          */
 196         new_refs = 0;
 197         for (ref = remote_refs; ref; ref = ref->next) {
 198                 char old_hex[60], *new_hex;
 199                 if (!ref->peer_ref)
 200                         continue;
 201                 if (!memcmp(ref->old_sha1, ref->peer_ref->new_sha1, 20)) {
 202                         fprintf(stderr, "'%s': up-to-date\n", ref->name);
 203                         continue;
 204                 }
 205
 206                 /* This part determines what can overwrite what.
 207                  * The rules are:
 208                  *
 209                  * (0) you can always use --force or +A:B notation to
 210                  *     selectively force individual ref pairs.
 211                  *
 212                  * (1) if the old thing does not exist, it is OK.
 213                  *
 214                  * (2) if you do not have the old thing, you are not allowed
 215                  *     to overwrite it; you would not know what you are losing
 216                  *     otherwise.
 217                  *
 218                  * (3) if both new and old are commit-ish, and new is a
 219                  *     descendant of old, it is OK.
 220                  */
 221
 222                 if (!force_update &&
 223                     !is_zero_sha1(ref->old_sha1) &&
 224                     !ref->force) {
 225                         if (!has_sha1_file(ref->old_sha1)) {
 226                                 error("remote '%s' object %s does not "
 227                                       "exist on local",
 228                                       ref->name, sha1_to_hex(ref->old_sha1));
 229                                 continue;
 230                         }
 231
 232                         /* We assume that local is fsck-clean.  Otherwise
 233                          * you _could_ have an old tag which points at
 234                          * something you do not have, which may or may not
 235                          * be a commit.
 236                          */
 237                         if (!ref_newer(ref->peer_ref->new_sha1,
 238                                        ref->old_sha1)) {
 239                                 error("remote ref '%s' is not a strict "
 240                                       "subset of local ref '%s'.", ref->name,
 241                                       ref->peer_ref->name);
 242                                 continue;
 243                         }
 244                 }
 245                 memcpy(ref->new_sha1, ref->peer_ref->new_sha1, 20);
 246                 if (is_zero_sha1(ref->new_sha1)) {
 247                         error("cannot happen anymore");
 248                         continue;
 249                 }
 250                 new_refs++;
 251                 strcpy(old_hex, sha1_to_hex(ref->old_sha1));
 252                 new_hex = sha1_to_hex(ref->new_sha1);
 253                 packet_write(out, "%s %s %s", old_hex, new_hex, ref->name);
 254                 fprintf(stderr, "updating '%s'", ref->name);
 255                 if (strcmp(ref->name, ref->peer_ref->name))
 256                         fprintf(stderr, " using '%s'", ref->peer_ref->name);
 257                 fprintf(stderr, "\n  from %s\n  to   %s\n", old_hex, new_hex);
 258         }
 259
 260         packet_flush(out);
 261         if (new_refs)
 262                 pack_objects(out, remote_refs);
 263         close(out);
 264         return 0;
 265 }
 266
 267
 268 int main(int argc, char **argv)
 269 {
 270         int i, nr_heads = 0;
 271         char *dest = NULL;
 272         char **heads = NULL;
 273         int fd[2], ret;
 274         pid_t pid;
 275
 276         setup_git_directory();
 277         argv++;
 278         for (i = 1; i < argc; i++, argv++) {
 279                 char *arg = *argv;
 280
 281                 if (*arg == '-') {
 282                         if (!strncmp(arg, "--exec=", 7)) {
 283                                 exec = arg + 7;
 284                                 continue;
 285                         }
 286                         if (!strcmp(arg, "--all")) {
 287                                 send_all = 1;
 288                                 continue;
 289                         }
 290                         if (!strcmp(arg, "--force")) {
 291                                 force_update = 1;
 292                                 continue;
 293                         }
 294                         usage(send_pack_usage);
 295                 }
 296                 if (!dest) {
 297                         dest = arg;
 298                         continue;
 299                 }
 300                 heads = argv;
 301                 nr_heads = argc - i;
 302                 break;
 303         }
 304         if (!dest)
 305                 usage(send_pack_usage);
 306         if (heads && send_all)
 307                 usage(send_pack_usage);
 308         pid = git_connect(fd, dest, exec);
 309         if (pid < 0)
 310                 return 1;
 311         ret = send_pack(fd[0], fd[1], nr_heads, heads);
 312         close(fd[0]);
 313         close(fd[1]);
 314         finish_connect(pid);
 315         return ret;
 316 }