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 int ref_newer(const unsigned char *new_sha1,
 109                      const unsigned char *old_sha1)
 110 {
 111         struct object *o;
 112         struct commit *old, *new;
 113         struct commit_list *list;
 114
 115         /* Both new and old must be commit-ish and new is descendant of
 116          * old.  Otherwise we require --force.
 117          */
 118         o = deref_tag(parse_object(old_sha1));
 119         if (!o || o->type != commit_type)
 120                 return 0;
 121         old = (struct commit *) o;
 122
 123         o = deref_tag(parse_object(new_sha1));
 124         if (!o || o->type != commit_type)
 125                 return 0;
 126         new = (struct commit *) o;
 127
 128         if (parse_commit(new) < 0)
 129                 return 0;
 130         list = NULL;
 131         commit_list_insert(new, &list);
 132         while (list) {
 133                 new = pop_most_recent_commit(&list, 1);
 134                 if (new == old)
 135                         return 1;
 136         }
 137         return 0;
 138 }
 139
 140 static struct ref *local_refs, **local_tail;
 141 static struct ref *remote_refs, **remote_tail;
 142
 143 static int one_local_ref(const char *refname, const unsigned char *sha1)
 144 {
 145         struct ref *ref;
 146         int len = strlen(refname) + 1;
 147         ref = xcalloc(1, sizeof(*ref) + len);
 148         memcpy(ref->new_sha1, sha1, 20);
 149         memcpy(ref->name, refname, len);
 150         *local_tail = ref;
 151         local_tail = &ref->next;
 152         return 0;
 153 }
 154
 155 static void get_local_heads(void)
 156 {
 157         local_tail = &local_refs;
 158         for_each_ref(one_local_ref);
 159 }
 160
 161 static int send_pack(int in, int out, int nr_refspec, char **refspec)
 162 {
 163         struct ref *ref;
 164         int new_refs;
 165
 166         /* No funny business with the matcher */
 167         remote_tail = get_remote_heads(in, &remote_refs, 0, NULL);
 168         get_local_heads();
 169
 170         /* match them up */
 171         if (!remote_tail)
 172                 remote_tail = &remote_refs;
 173         if (match_refs(local_refs, remote_refs, &remote_tail,
 174                        nr_refspec, refspec, send_all))
 175                 return -1;
 176         /*
 177          * Finally, tell the other end!
 178          */
 179         new_refs = 0;
 180         for (ref = remote_refs; ref; ref = ref->next) {
 181                 char old_hex[60], *new_hex;
 182                 if (!ref->peer_ref)
 183                         continue;
 184                 if (!memcmp(ref->old_sha1, ref->peer_ref->new_sha1, 20)) {
 185                         fprintf(stderr, "'%s': up-to-date\n", ref->name);
 186                         continue;
 187                 }
 188
 189                 /* This part determines what can overwrite what.
 190                  * The rules are:
 191                  *
 192                  * (0) you can always use --force.
 193                  *
 194                  * (1) if the old thing does not exist, it is OK.
 195                  *
 196                  * (2) if you do not have the old thing, you are not allowed
 197                  *     to overwrite it; you would not know what you are losing
 198                  *     otherwise.
 199                  *
 200                  * (3) if both new and old are commit-ish, and new is a
 201                  *     descendant of old, it is OK.
 202                  */
 203
 204                 if (!force_update && !is_zero_sha1(ref->old_sha1)) {
 205                         if (!has_sha1_file(ref->old_sha1)) {
 206                                 error("remote '%s' object %s does not "
 207                                       "exist on local",
 208                                       ref->name, sha1_to_hex(ref->old_sha1));
 209                                 continue;
 210                         }
 211                         /* We assume that local is fsck-clean.  Otherwise
 212                          * you _could_ have a old tag which points at
 213                          * something you do not have which may or may not
 214                          * be a commit.
 215                          */
 216                         if (!ref_newer(ref->peer_ref->new_sha1,
 217                                        ref->old_sha1)) {
 218                                 error("remote ref '%s' is not a strict "
 219                                       "subset of local ref '%s'.", ref->name,
 220                                       ref->peer_ref->name);
 221                                 continue;
 222                         }
 223                 }
 224                 memcpy(ref->new_sha1, ref->peer_ref->new_sha1, 20);
 225                 if (is_zero_sha1(ref->new_sha1)) {
 226                         error("cannot happen anymore");
 227                         continue;
 228                 }
 229                 new_refs++;
 230                 strcpy(old_hex, sha1_to_hex(ref->old_sha1));
 231                 new_hex = sha1_to_hex(ref->new_sha1);
 232                 packet_write(out, "%s %s %s", old_hex, new_hex, ref->name);
 233                 fprintf(stderr, "updating '%s'", ref->name);
 234                 if (strcmp(ref->name, ref->peer_ref->name))
 235                         fprintf(stderr, " using '%s'", ref->peer_ref->name);
 236                 fprintf(stderr, "\n  from %s\n  to   %s\n", old_hex, new_hex);
 237         }
 238
 239         packet_flush(out);
 240         if (new_refs)
 241                 pack_objects(out, remote_refs);
 242         close(out);
 243         return 0;
 244 }
 245
 246
 247 int main(int argc, char **argv)
 248 {
 249         int i, nr_heads = 0;
 250         char *dest = NULL;
 251         char **heads = NULL;
 252         int fd[2], ret;
 253         pid_t pid;
 254
 255         argv++;
 256         for (i = 1; i < argc; i++, argv++) {
 257                 char *arg = *argv;
 258
 259                 if (*arg == '-') {
 260                         if (!strncmp(arg, "--exec=", 7)) {
 261                                 exec = arg + 7;
 262                                 continue;
 263                         }
 264                         if (!strcmp(arg, "--all")) {
 265                                 send_all = 1;
 266                                 continue;
 267                         }
 268                         if (!strcmp(arg, "--force")) {
 269                                 force_update = 1;
 270                                 continue;
 271                         }
 272                         usage(send_pack_usage);
 273                 }
 274                 if (!dest) {
 275                         dest = arg;
 276                         continue;
 277                 }
 278                 heads = argv;
 279                 nr_heads = argc - i;
 280                 break;
 281         }
 282         if (!dest)
 283                 usage(send_pack_usage);
 284         if (heads && send_all)
 285                 usage(send_pack_usage);
 286         pid = git_connect(fd, dest, exec);
 287         if (pid < 0)
 288                 return 1;
 289         ret = send_pack(fd[0], fd[1], nr_heads, heads);
 290         close(fd[0]);
 291         close(fd[1]);
 292         finish_connect(pid);
 293         return ret;
 294 }