builtin-bundle.c

   1 #include "cache.h"
   2 #include "object.h"
   3 #include "commit.h"
   4 #include "diff.h"
   5 #include "revision.h"
   6 #include "list-objects.h"
   7 #include "exec_cmd.h"
   8
   9 /*
  10  * Basic handler for bundle files to connect repositories via sneakernet.
  11  * Invocation must include action.
  12  * This function can create a bundle or provide information on an existing
  13  * bundle supporting git-fetch, git-pull, and git-ls-remote
  14  */
  15
  16 static const char *bundle_usage="git-bundle (--create <bundle> <git-rev-list args> | --verify <bundle> | --list-heads <bundle> [refname]... | --unbundle <bundle> [refname]... )";
  17
  18 static const char bundle_signature[] = "# v2 git bundle\n";
  19
  20 struct ref_list {
  21         unsigned int nr, alloc;
  22         struct {
  23                 unsigned char sha1[20];
  24                 char *name;
  25         } *list;
  26 };
  27
  28 static void add_to_ref_list(const unsigned char *sha1, const char *name,
  29                 struct ref_list *list)
  30 {
  31         if (list->nr + 1 >= list->alloc) {
  32                 list->alloc = alloc_nr(list->nr + 1);
  33                 list->list = xrealloc(list->list,
  34                                 list->alloc * sizeof(list->list[0]));
  35         }
  36         memcpy(list->list[list->nr].sha1, sha1, 20);
  37         list->list[list->nr].name = xstrdup(name);
  38         list->nr++;
  39 }
  40
  41 struct bundle_header {
  42         struct ref_list prerequisites, references;
  43 };
  44
  45 /* this function returns the length of the string */
  46 static int read_string(int fd, char *buffer, int size)
  47 {
  48         int i;
  49         for (i = 0; i < size - 1; i++) {
  50                 int count = read(fd, buffer + i, 1);
  51                 if (count < 0)
  52                         return error("Read error: %s", strerror(errno));
  53                 if (count == 0) {
  54                         i--;
  55                         break;
  56                 }
  57                 if (buffer[i] == '\n')
  58                         break;
  59         }
  60         buffer[i + 1] = '\0';
  61         return i + 1;
  62 }
  63
  64 /* returns an fd */
  65 static int read_header(const char *path, struct bundle_header *header) {
  66         char buffer[1024];
  67         int fd = open(path, O_RDONLY);
  68
  69         if (fd < 0)
  70                 return error("could not open '%s'", path);
  71         if (read_string(fd, buffer, sizeof(buffer)) < 0 ||
  72                         strcmp(buffer, bundle_signature)) {
  73                 close(fd);
  74                 return error("'%s' does not look like a v2 bundle file", path);
  75         }
  76         while (read_string(fd, buffer, sizeof(buffer)) > 0
  77                         && buffer[0] != '\n') {
  78                 int offset = buffer[0] == '-' ? 1 : 0;
  79                 int len = strlen(buffer);
  80                 unsigned char sha1[20];
  81                 struct ref_list *list = offset ? &header->prerequisites
  82                         : &header->references;
  83                 if (get_sha1_hex(buffer + offset, sha1)) {
  84                         close(fd);
  85                         return error("invalid SHA1: %s", buffer);
  86                 }
  87                 if (buffer[len - 1] == '\n')
  88                         buffer[len - 1] = '\0';
  89                 add_to_ref_list(sha1, buffer + 41 + offset, list);
  90         }
  91         return fd;
  92 }
  93
  94 /* if in && *in >= 0, take that as input file descriptor instead */
  95 static int fork_with_pipe(const char **argv, int *in, int *out)
  96 {
  97         int needs_in, needs_out;
  98         int fdin[2], fdout[2], pid;
  99
 100         needs_in = in && *in < 0;
 101         if (needs_in) {
 102                 if (pipe(fdin) < 0)
 103                         return error("could not setup pipe");
 104                 *in = fdin[1];
 105         }
 106
 107         needs_out = out && *out < 0;
 108         if (needs_out) {
 109                 if (pipe(fdout) < 0)
 110                         return error("could not setup pipe");
 111                 *out = fdout[0];
 112         }
 113
 114         if ((pid = fork()) < 0) {
 115                 if (needs_in) {
 116                         close(fdin[0]);
 117                         close(fdin[1]);
 118                 }
 119                 if (needs_out) {
 120                         close(fdout[0]);
 121                         close(fdout[1]);
 122                 }
 123                 return error("could not fork");
 124         }
 125         if (!pid) {
 126                 if (needs_in) {
 127                         dup2(fdin[0], 0);
 128                         close(fdin[0]);
 129                         close(fdin[1]);
 130                 } else if (in)
 131                         dup2(*in, 0);
 132                 if (needs_out) {
 133                         dup2(fdout[1], 1);
 134                         close(fdout[0]);
 135                         close(fdout[1]);
 136                 } else if (out)
 137                         dup2(*out, 1);
 138                 exit(execv_git_cmd(argv));
 139         }
 140         if (needs_in)
 141                 close(fdin[0]);
 142         if (needs_out)
 143                 close(fdout[1]);
 144         return pid;
 145 }
 146
 147 static int verify_bundle(struct bundle_header *header)
 148 {
 149         /*
 150          * Do fast check, then if any prereqs are missing then go line by line
 151          * to be verbose about the errors
 152          */
 153         struct ref_list *p = &header->prerequisites;
 154         const char *argv[5] = {"rev-list", "--stdin", "--not", "--all", NULL};
 155         int pid, in, out, i, ret = 0;
 156         char buffer[1024];
 157
 158         in = out = -1;
 159         pid = fork_with_pipe(argv, &in, &out);
 160         if (pid < 0)
 161                 return error("Could not fork rev-list");
 162         if (!fork()) {
 163                 for (i = 0; i < p->nr; i++) {
 164                         write(in, sha1_to_hex(p->list[i].sha1), 40);
 165                         write(in, "\n", 1);
 166                 }
 167                 close(in);
 168                 exit(0);
 169         }
 170         close(in);
 171         while (read_string(out, buffer, sizeof(buffer)) > 0) {
 172                 if (ret++ == 0)
 173                         error ("The bundle requires the following commits you lack:");
 174                 fprintf(stderr, "%s", buffer);
 175         }
 176         close(out);
 177         while (waitpid(pid, &i, 0) < 0)
 178                 if (errno != EINTR)
 179                         return -1;
 180         if (!ret && (!WIFEXITED(i) || WEXITSTATUS(i)))
 181                 return error("At least one prerequisite is lacking.");
 182
 183         return ret;
 184 }
 185
 186 static int list_heads(struct bundle_header *header, int argc, const char **argv)
 187 {
 188         int i;
 189         struct ref_list *r = &header->references;
 190
 191         for (i = 0; i < r->nr; i++) {
 192                 if (argc > 1) {
 193                         int j;
 194                         for (j = 1; j < argc; j++)
 195                                 if (!strcmp(r->list[i].name, argv[j]))
 196                                         break;
 197                         if (j == argc)
 198                                 continue;
 199                 }
 200                 printf("%s %s\n", sha1_to_hex(r->list[i].sha1),
 201                                 r->list[i].name);
 202         }
 203         return 0;
 204 }
 205
 206 static void show_commit(struct commit *commit)
 207 {
 208         write(1, sha1_to_hex(commit->object.sha1), 40);
 209         write(1, "\n", 1);
 210         if (commit->parents) {
 211                 free_commit_list(commit->parents);
 212                 commit->parents = NULL;
 213         }
 214 }
 215
 216 static void show_object(struct object_array_entry *p)
 217 {
 218         /* An object with name "foo\n0000000..." can be used to
 219          *          * confuse downstream git-pack-objects very badly.
 220          *                   */
 221         const char *ep = strchr(p->name, '\n');
 222         int len = ep ? ep - p->name : strlen(p->name);
 223         write(1, sha1_to_hex(p->item->sha1), 40);
 224         write(1, " ", 1);
 225         if (len)
 226                 write(1, p->name, len);
 227         write(1, "\n", 1);
 228 }
 229
 230 static int create_bundle(struct bundle_header *header, const char *path,
 231                 int argc, const char **argv)
 232 {
 233         int bundle_fd = -1;
 234         const char **argv_boundary = xmalloc((argc + 3) * sizeof(const char *));
 235         const char **argv_pack = xmalloc(4 * sizeof(const char *));
 236         int pid, in, out, i, status;
 237         char buffer[1024];
 238         struct rev_info revs;
 239
 240         bundle_fd = (!strcmp(path, "-") ? 1 :
 241                         open(path, O_CREAT | O_WRONLY, 0666));
 242         if (bundle_fd < 0)
 243                 return error("Could not write to '%s'", path);
 244
 245         /* write signature */
 246         write(bundle_fd, bundle_signature, strlen(bundle_signature));
 247
 248         /* write prerequisites */
 249         memcpy(argv_boundary + 2, argv + 1, argc * sizeof(const char *));
 250         argv_boundary[0] = "rev-list";
 251         argv_boundary[1] = "--boundary";
 252         argv_boundary[argc + 1] = NULL;
 253         out = -1;
 254         pid = fork_with_pipe(argv_boundary, NULL, &out);
 255         if (pid < 0)
 256                 return -1;
 257         while ((i = read_string(out, buffer, sizeof(buffer))) > 0)
 258                 if (buffer[0] == '-')
 259                         write(bundle_fd, buffer, i);
 260         while ((i = waitpid(pid, &status, 0)) < 0)
 261                 if (errno != EINTR)
 262                         return error("rev-list died");
 263         if (!WIFEXITED(status) || WEXITSTATUS(status))
 264                 return error("rev-list died %d", WEXITSTATUS(status));
 265
 266         /* write references */
 267         save_commit_buffer = 0;
 268         init_revisions(&revs, NULL);
 269         revs.tag_objects = 1;
 270         revs.tree_objects = 1;
 271         revs.blob_objects = 1;
 272         argc = setup_revisions(argc, argv, &revs, NULL);
 273         if (argc > 1)
 274                 return error("unrecognized argument: %s'", argv[1]);
 275         for (i = 0; i < revs.pending.nr; i++) {
 276                 struct object_array_entry *e = revs.pending.objects + i;
 277                 if (!(e->item->flags & UNINTERESTING)) {
 278                         unsigned char sha1[20];
 279                         char *ref;
 280                         if (dwim_ref(e->name, strlen(e->name), sha1, &ref) != 1)
 281                                 continue;
 282                         write(bundle_fd, sha1_to_hex(e->item->sha1), 40);
 283                         write(bundle_fd, " ", 1);
 284                         write(bundle_fd, ref, strlen(ref));
 285                         write(bundle_fd, "\n", 1);
 286                         free(ref);
 287                 }
 288         }
 289
 290         /* end header */
 291         write(bundle_fd, "\n", 1);
 292
 293         /* write pack */
 294         argv_pack[0] = "pack-objects";
 295         argv_pack[1] = "--all-progress";
 296         argv_pack[2] = "--stdout";
 297         argv_pack[3] = NULL;
 298         in = -1;
 299         out = bundle_fd;
 300         pid = fork_with_pipe(argv_pack, &in, &out);
 301         if (pid < 0)
 302                 return error("Could not spawn pack-objects");
 303         close(1);
 304         close(bundle_fd);
 305         dup2(in, 1);
 306         close(in);
 307         prepare_revision_walk(&revs);
 308         traverse_commit_list(&revs, show_commit, show_object);
 309         close(1);
 310         while (waitpid(pid, &status, 0) < 0)
 311                 if (errno != EINTR)
 312                         return -1;
 313         if (!WIFEXITED(status) || WEXITSTATUS(status))
 314                 return error ("pack-objects died");
 315         return 0;
 316 }
 317
 318 static int unbundle(struct bundle_header *header, int bundle_fd,
 319                 int argc, const char **argv)
 320 {
 321         const char *argv_index_pack[] = {"index-pack", "--stdin", NULL};
 322         int pid, status, dev_null;
 323
 324         if (verify_bundle(header))
 325                 return -1;
 326         dev_null = open("/dev/null", O_WRONLY);
 327         pid = fork_with_pipe(argv_index_pack, &bundle_fd, &dev_null);
 328         if (pid < 0)
 329                 return error("Could not spawn index-pack");
 330         close(bundle_fd);
 331         while (waitpid(pid, &status, 0) < 0)
 332                 if (errno != EINTR)
 333                         return error("index-pack died");
 334         if (!WIFEXITED(status) || WEXITSTATUS(status))
 335                 return error("index-pack exited with status %d",
 336                                 WEXITSTATUS(status));
 337         return list_heads(header, argc, argv);
 338 }
 339
 340 int cmd_bundle(int argc, const char **argv, const char *prefix)
 341 {
 342         struct bundle_header header;
 343         int nongit = 0;
 344         const char *cmd, *bundle_file;
 345         int bundle_fd = -1;
 346         char buffer[PATH_MAX];
 347
 348         if (argc < 3)
 349                 usage(bundle_usage);
 350
 351         cmd = argv[1];
 352         bundle_file = argv[2];
 353         argc -= 2;
 354         argv += 2;
 355
 356         prefix = setup_git_directory_gently(&nongit);
 357         if (prefix && bundle_file[0] != '/') {
 358                 snprintf(buffer, sizeof(buffer), "%s/%s", prefix, bundle_file);
 359                 bundle_file = buffer;
 360         }
 361
 362         memset(&header, 0, sizeof(header));
 363         if (strcmp(cmd, "create") &&
 364                         !(bundle_fd = read_header(bundle_file, &header)))
 365                 return 1;
 366
 367         if (!strcmp(cmd, "verify")) {
 368                 close(bundle_fd);
 369                 if (verify_bundle(&header))
 370                         return 1;
 371                 fprintf(stderr, "%s is okay\n", bundle_file);
 372                 return 0;
 373         }
 374         if (!strcmp(cmd, "list-heads")) {
 375                 close(bundle_fd);
 376                 return !!list_heads(&header, argc, argv);
 377         }
 378         if (!strcmp(cmd, "create")) {
 379                 if (nongit)
 380                         die("Need a repository to create a bundle.");
 381                 return !!create_bundle(&header, bundle_file, argc, argv);
 382         } else if (!strcmp(cmd, "unbundle")) {
 383                 if (nongit)
 384                         die("Need a repository to unbundle.");
 385                 return !!unbundle(&header, bundle_fd, argc, argv);
 386         } else
 387                 usage(bundle_usage);
 388 }
 389