send-pack.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "pkt-line.h"
   4
   5 static const char send_pack_usage[] =
   6 "git-send-pack [--exec=git-receive-pack] [host:]directory [heads]*";
   7 static const char *exec = "git-receive-pack";
   8
   9 struct ref {
  10         struct ref *next;
  11         unsigned char old_sha1[20];
  12         unsigned char new_sha1[20];
  13         char name[0];
  14 };
  15
  16 static int is_zero_sha1(const unsigned char *sha1)
  17 {
  18         int i;
  19
  20         for (i = 0; i < 20; i++) {
  21                 if (*sha1++)
  22                         return 0;
  23         }
  24         return 1;
  25 }
  26
  27 static void exec_pack_objects(void)
  28 {
  29         static char *args[] = {
  30                 "git-pack-objects",
  31                 "--stdout",
  32                 NULL
  33         };
  34         execvp("git-pack-objects", args);
  35         die("git-pack-objects exec failed (%s)", strerror(errno));
  36 }
  37
  38 static void exec_rev_list(struct ref *refs)
  39 {
  40         static char *args[1000];
  41         int i = 0;
  42
  43         args[i++] = "git-rev-list";     /* 0 */
  44         args[i++] = "--objects";        /* 1 */
  45         while (refs) {
  46                 char *buf = malloc(100);
  47                 if (i > 900)
  48                         die("git-rev-list environment overflow");
  49                 if (!is_zero_sha1(refs->old_sha1)) {
  50                         args[i++] = buf;
  51                         snprintf(buf, 50, "^%s", sha1_to_hex(refs->old_sha1));
  52                         buf += 50;
  53                 }
  54                 if (!is_zero_sha1(refs->new_sha1)) {
  55                         args[i++] = buf;
  56                         snprintf(buf, 50, "%s", sha1_to_hex(refs->new_sha1));
  57                 }
  58                 refs = refs->next;
  59         }
  60         args[i] = NULL;
  61         execvp("git-rev-list", args);
  62         die("git-rev-list exec failed (%s)", strerror(errno));
  63 }
  64
  65 static void rev_list(int fd, struct ref *refs)
  66 {
  67         int pipe_fd[2];
  68         pid_t pack_objects_pid;
  69
  70         if (pipe(pipe_fd) < 0)
  71                 die("rev-list setup: pipe failed");
  72         pack_objects_pid = fork();
  73         if (!pack_objects_pid) {
  74                 dup2(pipe_fd[0], 0);
  75                 dup2(fd, 1);
  76                 close(pipe_fd[0]);
  77                 close(pipe_fd[1]);
  78                 close(fd);
  79                 exec_pack_objects();
  80                 die("pack-objects setup failed");
  81         }
  82         if (pack_objects_pid < 0)
  83                 die("pack-objects fork failed");
  84         dup2(pipe_fd[1], 1);
  85         close(pipe_fd[0]);
  86         close(pipe_fd[1]);
  87         close(fd);
  88         exec_rev_list(refs);
  89 }
  90
  91 static int pack_objects(int fd, struct ref *refs)
  92 {
  93         pid_t rev_list_pid;
  94
  95         rev_list_pid = fork();
  96         if (!rev_list_pid) {
  97                 rev_list(fd, refs);
  98                 die("rev-list setup failed");
  99         }
 100         if (rev_list_pid < 0)
 101                 die("rev-list fork failed");
 102         /*
 103          * We don't wait for the rev-list pipeline in the parent:
 104          * we end up waiting for the other end instead
 105          */
 106         return 0;
 107 }
 108
 109 static int read_ref(const char *ref, unsigned char *sha1)
 110 {
 111         int fd, ret;
 112         char buffer[60];
 113
 114         fd = open(git_path("%s", ref), O_RDONLY);
 115         if (fd < 0)
 116                 return -1;
 117         ret = -1;
 118         if (read(fd, buffer, sizeof(buffer)) >= 40)
 119                 ret = get_sha1_hex(buffer, sha1);
 120         close(fd);
 121         return ret;
 122 }
 123
 124 static int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
 125 {
 126         if (!has_sha1_file(old_sha1))
 127                 return 0;
 128         /*
 129          * FIXME! It is not correct to say that the new one is newer
 130          * just because we don't have the old one!
 131          *
 132          * We should really see if we can reach the old_sha1 commit
 133          * from the new_sha1 one.
 134          */
 135         return 1;
 136 }
 137
 138 static int local_ref_nr_match;
 139 static char **local_ref_match;
 140 static struct ref **local_ref_list;
 141
 142 static int try_to_match(const char *refname, const unsigned char *sha1)
 143 {
 144         struct ref *ref;
 145         int len;
 146
 147         if (!path_match(refname, local_ref_nr_match, local_ref_match))
 148                 return 0;
 149
 150         len = strlen(refname)+1;
 151         ref = xmalloc(sizeof(*ref) + len);
 152         memset(ref->old_sha1, 0, 20);
 153         memcpy(ref->new_sha1, sha1, 20);
 154         memcpy(ref->name, refname, len);
 155         ref->next = NULL;
 156         *local_ref_list = ref;
 157         local_ref_list = &ref->next;
 158         return 0;
 159 }
 160
 161 static int send_pack(int in, int out, int nr_match, char **match)
 162 {
 163         struct ref *ref_list = NULL, **last_ref = &ref_list;
 164         struct ref *ref;
 165         int new_refs;
 166
 167         /*
 168          * Read all the refs from the other end
 169          */
 170         for (;;) {
 171                 unsigned char old_sha1[20];
 172                 static char buffer[1000];
 173                 char *name;
 174                 int len;
 175
 176                 len = packet_read_line(in, buffer, sizeof(buffer));
 177                 if (!len)
 178                         break;
 179                 if (buffer[len-1] == '\n')
 180                         buffer[--len] = 0;
 181
 182                 if (len < 42 || get_sha1_hex(buffer, old_sha1) || buffer[40] != ' ')
 183                         die("protocol error: expected sha/ref, got '%s'", buffer);
 184                 name = buffer + 41;
 185                 ref = xmalloc(sizeof(*ref) + len - 40);
 186                 memcpy(ref->old_sha1, old_sha1, 20);
 187                 memset(ref->new_sha1, 0, 20);
 188                 memcpy(ref->name, buffer + 41, len - 40);
 189                 ref->next = NULL;
 190                 *last_ref = ref;
 191                 last_ref = &ref->next;
 192         }
 193
 194         /*
 195          * Go through the refs, see if we want to update
 196          * any of them..
 197          */
 198         for (ref = ref_list; ref; ref = ref->next) {
 199                 unsigned char new_sha1[20];
 200                 char *name = ref->name;
 201
 202                 if (nr_match && !path_match(name, nr_match, match))
 203                         continue;
 204
 205                 if (read_ref(name, new_sha1) < 0)
 206                         continue;
 207
 208                 if (!memcmp(ref->old_sha1, new_sha1, 20)) {
 209                         fprintf(stderr, "'%s' unchanged\n", name);
 210                         continue;
 211                 }
 212
 213                 if (!ref_newer(new_sha1, ref->old_sha1)) {
 214                         error("remote '%s' points to object I don't have", name);
 215                         continue;
 216                 }
 217
 218                 /* Ok, mark it for update */
 219                 memcpy(ref->new_sha1, new_sha1, 20);
 220         }
 221
 222         /*
 223          * See if we have any refs that the other end didn't have
 224          */
 225         if (nr_match) {
 226                 local_ref_nr_match = nr_match;
 227                 local_ref_match = match;
 228                 local_ref_list = last_ref;
 229                 for_each_ref(try_to_match);
 230         }
 231
 232         /*
 233          * Finally, tell the other end!
 234          */
 235         new_refs = 0;
 236         for (ref = ref_list; ref; ref = ref->next) {
 237                 char old_hex[60], *new_hex;
 238                 if (is_zero_sha1(ref->new_sha1))
 239                         continue;
 240                 new_refs++;
 241                 strcpy(old_hex, sha1_to_hex(ref->old_sha1));
 242                 new_hex = sha1_to_hex(ref->new_sha1);
 243                 packet_write(out, "%s %s %s", old_hex, new_hex, ref->name);
 244                 fprintf(stderr, "'%s': updating from %s to %s\n", ref->name, old_hex, new_hex);
 245         }
 246
 247         packet_flush(out);
 248         if (new_refs)
 249                 pack_objects(out, ref_list);
 250         close(out);
 251         return 0;
 252 }
 253
 254 int main(int argc, char **argv)
 255 {
 256         int i, nr_heads = 0;
 257         char *dest = NULL;
 258         char **heads = NULL;
 259         int fd[2], ret;
 260         pid_t pid;
 261
 262         argv++;
 263         for (i = 1; i < argc; i++) {
 264                 char *arg = *argv++;
 265
 266                 if (*arg == '-') {
 267                         if (!strncmp(arg, "--exec=", 7)) {
 268                                 exec = arg + 7;
 269                                 continue;
 270                         }
 271                         usage(send_pack_usage);
 272                 }
 273                 dest = arg;
 274                 heads = argv;
 275                 nr_heads = argc - i -1;
 276                 break;
 277         }
 278         if (!dest)
 279                 usage(send_pack_usage);
 280         pid = git_connect(fd, dest, exec);
 281         if (pid < 0)
 282                 return 1;
 283         ret = send_pack(fd[0], fd[1], nr_heads, heads);
 284         close(fd[0]);
 285         close(fd[1]);
 286         finish_connect(pid);
 287         return ret;
 288 }