send-pack.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "pkt-line.h"
   4
   5 static const char send_pack_usage[] = "git-send-pack [--exec=other] destination [heads]*";
   6 static const char *exec = "git-receive-pack";
   7
   8 struct ref {
   9         struct ref *next;
  10         unsigned char old_sha1[20];
  11         unsigned char new_sha1[20];
  12         char name[0];
  13 };
  14
  15 static int is_zero_sha1(const unsigned char *sha1)
  16 {
  17         int i;
  18
  19         for (i = 0; i < 20; i++) {
  20                 if (*sha1++)
  21                         return 0;
  22         }
  23         return 1;
  24 }
  25
  26 static void exec_pack_objects(void)
  27 {
  28         static char *args[] = {
  29                 "git-pack-objects",
  30                 "--stdout",
  31                 NULL
  32         };
  33         execvp("git-pack-objects", args);
  34         die("git-pack-objects exec failed (%s)", strerror(errno));
  35 }
  36
  37 static void exec_rev_list(struct ref *refs)
  38 {
  39         static char *args[1000];
  40         int i = 0;
  41
  42         args[i++] = "git-rev-list";     /* 0 */
  43         args[i++] = "--objects";        /* 1 */
  44         while (refs) {
  45                 char *buf = malloc(100);
  46                 if (i > 900)
  47                         die("git-rev-list environment overflow");
  48                 if (!is_zero_sha1(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 read_ref(const char *ref, unsigned char *sha1)
 109 {
 110         int fd, ret;
 111         char buffer[60];
 112
 113         fd = open(git_path("%s", ref), O_RDONLY);
 114         if (fd < 0)
 115                 return -1;
 116         ret = -1;
 117         if (read(fd, buffer, sizeof(buffer)) >= 40)
 118                 ret = get_sha1_hex(buffer, sha1);
 119         close(fd);
 120         return ret;
 121 }
 122
 123 static int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
 124 {
 125         if (!has_sha1_file(old_sha1))
 126                 return 0;
 127         /*
 128          * FIXME! It is not correct to say that the new one is newer
 129          * just because we don't have the old one!
 130          *
 131          * We should really see if we can reach the old_sha1 commit
 132          * from the new_sha1 one.
 133          */
 134         return 1;
 135 }
 136
 137 static int local_ref_nr_match;
 138 static char **local_ref_match;
 139 static struct ref **local_ref_list;
 140
 141 static int try_to_match(const char *refname, const unsigned char *sha1)
 142 {
 143         struct ref *ref;
 144         int len;
 145
 146         if (!path_match(refname, local_ref_nr_match, local_ref_match))
 147                 return 0;
 148
 149         len = strlen(refname)+1;
 150         ref = xmalloc(sizeof(*ref) + len);
 151         memset(ref->old_sha1, 0, 20);
 152         memcpy(ref->new_sha1, sha1, 20);
 153         memcpy(ref->name, refname, len);
 154         ref->next = NULL;
 155         *local_ref_list = ref;
 156         local_ref_list = &ref->next;
 157         return 0;
 158 }
 159
 160 static int send_pack(int in, int out, int nr_match, char **match)
 161 {
 162         struct ref *ref_list = NULL, **last_ref = &ref_list;
 163         struct ref *ref;
 164         int new_refs;
 165
 166         /*
 167          * Read all the refs from the other end
 168          */
 169         for (;;) {
 170                 unsigned char old_sha1[20];
 171                 static char buffer[1000];
 172                 char *name;
 173                 int len;
 174
 175                 len = packet_read_line(in, buffer, sizeof(buffer));
 176                 if (!len)
 177                         break;
 178                 if (buffer[len-1] == '\n')
 179                         buffer[--len] = 0;
 180
 181                 if (len < 42 || get_sha1_hex(buffer, old_sha1) || buffer[40] != ' ')
 182                         die("protocol error: expected sha/ref, got '%s'", buffer);
 183                 name = buffer + 41;
 184                 ref = xmalloc(sizeof(*ref) + len - 40);
 185                 memcpy(ref->old_sha1, old_sha1, 20);
 186                 memset(ref->new_sha1, 0, 20);
 187                 memcpy(ref->name, buffer + 41, len - 40);
 188                 ref->next = NULL;
 189                 *last_ref = ref;
 190                 last_ref = &ref->next;
 191         }
 192
 193         /*
 194          * Go through the refs, see if we want to update
 195          * any of them..
 196          */
 197         for (ref = ref_list; ref; ref = ref->next) {
 198                 unsigned char new_sha1[20];
 199                 char *name = ref->name;
 200
 201                 if (nr_match && !path_match(name, nr_match, match))
 202                         continue;
 203
 204                 if (read_ref(name, new_sha1) < 0)
 205                         continue;
 206
 207                 if (!memcmp(ref->old_sha1, new_sha1, 20)) {
 208                         fprintf(stderr, "'%s' unchanged\n", name);
 209                         continue;
 210                 }
 211
 212                 if (!ref_newer(new_sha1, ref->old_sha1)) {
 213                         error("remote '%s' points to object I don't have", name);
 214                         continue;
 215                 }
 216
 217                 /* Ok, mark it for update */
 218                 memcpy(ref->new_sha1, new_sha1, 20);
 219         }
 220
 221         /*
 222          * See if we have any refs that the other end didn't have
 223          */
 224         if (nr_match) {
 225                 local_ref_nr_match = nr_match;
 226                 local_ref_match = match;
 227                 local_ref_list = last_ref;
 228                 for_each_ref(try_to_match);
 229         }
 230
 231         /*
 232          * Finally, tell the other end!
 233          */
 234         new_refs = 0;
 235         for (ref = ref_list; ref; ref = ref->next) {
 236                 char old_hex[60], *new_hex;
 237                 if (is_zero_sha1(ref->new_sha1))
 238                         continue;
 239                 new_refs++;
 240                 strcpy(old_hex, sha1_to_hex(ref->old_sha1));
 241                 new_hex = sha1_to_hex(ref->new_sha1);
 242                 packet_write(out, "%s %s %s", old_hex, new_hex, ref->name);
 243                 fprintf(stderr, "'%s': updating from %s to %s\n", ref->name, old_hex, new_hex);
 244         }
 245
 246         packet_flush(out);
 247         if (new_refs)
 248                 pack_objects(out, ref_list);
 249         close(out);
 250         return 0;
 251 }
 252
 253 int main(int argc, char **argv)
 254 {
 255         int i, nr_heads = 0;
 256         char *dest = NULL;
 257         char **heads = NULL;
 258         int fd[2], ret;
 259         pid_t pid;
 260
 261         argv++;
 262         for (i = 1; i < argc; i++) {
 263                 char *arg = *argv++;
 264
 265                 if (*arg == '-') {
 266                         if (!strncmp(arg, "--exec=", 7)) {
 267                                 exec = arg + 7;
 268                                 continue;
 269                         }
 270                         usage(send_pack_usage);
 271                 }
 272                 dest = arg;
 273                 heads = argv;
 274                 nr_heads = argc - i -1;
 275                 break;
 276         }
 277         if (!dest)
 278                 usage(send_pack_usage);
 279         pid = git_connect(fd, dest, exec);
 280         if (pid < 0)
 281                 return 1;
 282         ret = send_pack(fd[0], fd[1], nr_heads, heads);
 283         close(fd[0]);
 284         close(fd[1]);
 285         finish_connect(pid);
 286         return ret;
 287 }