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 struct ref {
  11         struct ref *next;
  12         unsigned char sha1[20];
  13         char name[0];
  14 };
  15
  16 static struct ref *get_remote_refs(int fd, int nr_match, char **match)
  17 {
  18         struct ref *ref_list = NULL, **next_ref = &ref_list;
  19
  20         for (;;) {
  21                 static char line[1000];
  22                 unsigned char sha1[20];
  23                 struct ref *ref;
  24                 char *refname;
  25                 int len;
  26
  27                 len = packet_read_line(fd, line, sizeof(line));
  28                 if (!len)
  29                         break;
  30                 if (line[len-1] == '\n')
  31                         line[--len] = 0;
  32                 if (len < 42 || get_sha1_hex(line, sha1))
  33                         die("git-clone-pack: protocol error - expected ref descriptor, got '%s'", line);
  34                 refname = line+41;
  35                 len = len-40;
  36                 if (nr_match && !path_match(refname, nr_match, match))
  37                         continue;
  38                 ref = xmalloc(sizeof(struct ref) + len);
  39                 ref->next = NULL;
  40                 memcpy(ref->sha1, sha1, 20);
  41                 memcpy(ref->name, refname, len);
  42                 *next_ref = ref;
  43                 next_ref = &ref->next;
  44         }
  45         return ref_list;
  46 }
  47
  48 static void clone_handshake(int fd[2], struct ref *ref)
  49 {
  50         unsigned char sha1[20];
  51
  52         while (ref) {
  53                 packet_write(fd[1], "want %s\n", sha1_to_hex(ref->sha1));
  54                 ref = ref->next;
  55         }
  56         packet_flush(fd[1]);
  57
  58         /* We don't have nuttin' */
  59         packet_write(fd[1], "done\n");
  60         if (get_ack(fd[0], sha1))
  61                 error("Huh! git-clone-pack got positive ack for %s", sha1_to_hex(sha1));
  62 }
  63
  64 static int is_master(struct ref *ref)
  65 {
  66         return !strcmp(ref->name, "refs/heads/master");
  67 }
  68
  69 static void write_one_ref(struct ref *ref)
  70 {
  71         char *path = git_path(ref->name);
  72         int fd;
  73         char *hex;
  74
  75         if (safe_create_leading_directories(path))
  76                 die("unable to create leading directory for %s", ref->name);
  77         fd = open(path, O_CREAT | O_EXCL | O_WRONLY, 0666);
  78         if (fd < 0)
  79                 die("unable to create ref %s", ref->name);
  80         hex = sha1_to_hex(ref->sha1);
  81         hex[40] = '\n';
  82         if (write(fd, hex, 41) != 41)
  83                 die("unable to write ref %s", ref->name);
  84         close(fd);
  85 }
  86
  87 static void write_refs(struct ref *ref)
  88 {
  89         struct ref *head = NULL, *head_ptr, *master_ref;
  90         char *head_path;
  91
  92         if (!strcmp(ref->name, "HEAD")) {
  93                 head = ref;
  94                 ref = ref->next;
  95         }
  96         head_ptr = NULL;
  97         master_ref = NULL;
  98         while (ref) {
  99                 if (is_master(ref))
 100                         master_ref = ref;
 101                 if (head && !memcmp(ref->sha1, head->sha1, 20)) {
 102                         if (!head_ptr || ref == master_ref)
 103                                 head_ptr = ref;
 104                 }
 105                 write_one_ref(ref);
 106                 ref = ref->next;
 107         }
 108         if (!head)
 109                 return;
 110
 111         head_path = git_path("HEAD");
 112         if (!head_ptr) {
 113                 /*
 114                  * If we had a master ref, and it wasn't HEAD, we need to undo the
 115                  * symlink, and write a standalone HEAD. Give a warning, because that's
 116                  * really really wrong.
 117                  */
 118                 if (master_ref) {
 119                         error("HEAD doesn't point to any refs! Making standalone HEAD");
 120                         unlink(head_path);
 121                 }
 122                 write_one_ref(head);
 123                 return;
 124         }
 125
 126         /* We reset to the master branch if it's available */
 127         if (master_ref)
 128                 return;
 129
 130         /*
 131          * Uhhuh. Other end didn't have master. We start HEAD off with
 132          * the first branch with the same value.
 133          */
 134         unlink(head_path);
 135         if (symlink(head_ptr->name, head_path) < 0)
 136                 die("unable to link HEAD to %s", head_ptr->name);
 137 }
 138
 139 static int clone_pack(int fd[2], int nr_match, char **match)
 140 {
 141         struct ref *refs;
 142         int status;
 143         pid_t pid;
 144
 145         refs = get_remote_refs(fd[0], nr_match, match);
 146         if (!refs) {
 147                 packet_flush(fd[1]);
 148                 die("no matching remote head");
 149         }
 150         clone_handshake(fd, refs);
 151         pid = fork();
 152         if (pid < 0)
 153                 die("git-clone-pack: unable to fork off git-unpack-objects");
 154         if (!pid) {
 155                 dup2(fd[0], 0);
 156                 close(fd[0]);
 157                 close(fd[1]);
 158                 execlp("git-unpack-objects", "git-unpack-objects",
 159                         quiet ? "-q" : NULL, NULL);
 160                 die("git-unpack-objects exec failed");
 161         }
 162         close(fd[0]);
 163         close(fd[1]);
 164         while (waitpid(pid, &status, 0) < 0) {
 165                 if (errno != EINTR)
 166                         die("waiting for git-unpack-objects: %s", strerror(errno));
 167         }
 168         if (WIFEXITED(status)) {
 169                 int code = WEXITSTATUS(status);
 170                 if (code)
 171                         die("git-unpack-objects died with error code %d", code);
 172                 write_refs(refs);
 173                 return 0;
 174         }
 175         if (WIFSIGNALED(status)) {
 176                 int sig = WTERMSIG(status);
 177                 die("git-unpack-objects died of signal %d", sig);
 178         }
 179         die("Sherlock Holmes! git-unpack-objects died of unnatural causes %d!", status);
 180 }
 181
 182 int main(int argc, char **argv)
 183 {
 184         int i, ret, nr_heads;
 185         char *dest = NULL, **heads;
 186         int fd[2];
 187         pid_t pid;
 188
 189         nr_heads = 0;
 190         heads = NULL;
 191         for (i = 1; i < argc; i++) {
 192                 char *arg = argv[i];
 193
 194                 if (*arg == '-') {
 195                         if (!strcmp("-q", arg)) {
 196                                 quiet = 1;
 197                                 continue;
 198                         }
 199                         if (!strncmp("--exec=", arg, 7)) {
 200                                 exec = arg + 7;
 201                                 continue;
 202                         }
 203                         usage(clone_pack_usage);
 204                 }
 205                 dest = arg;
 206                 heads = argv + i + 1;
 207                 nr_heads = argc - i - 1;
 208                 break;
 209         }
 210         if (!dest)
 211                 usage(clone_pack_usage);
 212         pid = git_connect(fd, dest, exec);
 213         if (pid < 0)
 214                 return 1;
 215         ret = clone_pack(fd, nr_heads, heads);
 216         close(fd[0]);
 217         close(fd[1]);
 218         finish_connect(pid);
 219         return ret;
 220 }