upload-pack.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "pkt-line.h"
   4
   5 static const char upload_pack_usage[] = "git-upload-pack <dir>";
   6
   7 #define MAX_HAS (16)
   8 #define MAX_NEEDS (256)
   9 static int nr_has = 0, nr_needs = 0;
  10 static unsigned char has_sha1[MAX_HAS][20];
  11 static unsigned char needs_sha1[MAX_NEEDS][20];
  12
  13 static int strip(char *line, int len)
  14 {
  15         if (len && line[len-1] == '\n')
  16                 line[--len] = 0;
  17         return len;
  18 }
  19
  20 static void create_pack_file(void)
  21 {
  22         int fd[2];
  23         pid_t pid;
  24
  25         if (pipe(fd) < 0)
  26                 die("git-upload-pack: unable to create pipe");
  27         pid = fork();
  28         if (pid < 0)
  29                 die("git-upload-pack: unable to fork git-rev-list");
  30
  31         if (!pid) {
  32                 int i;
  33                 int args = nr_has + nr_needs + 5;
  34                 char **argv = xmalloc(args * sizeof(char *));
  35                 char *buf = xmalloc(args * 45);
  36                 char **p = argv;
  37
  38                 dup2(fd[1], 1);
  39                 close(0);
  40                 close(fd[0]);
  41                 close(fd[1]);
  42                 *p++ = "git-rev-list";
  43                 *p++ = "--objects";
  44                 for (i = 0; i < nr_needs; i++) {
  45                         *p++ = buf;
  46                         memcpy(buf, sha1_to_hex(needs_sha1[i]), 41);
  47                         buf += 41;
  48                 }
  49                 for (i = 0; i < nr_has; i++) {
  50                         *p++ = buf;
  51                         *buf++ = '^';
  52                         memcpy(buf, sha1_to_hex(has_sha1[i]), 41);
  53                         buf += 41;
  54                 }
  55                 *p++ = NULL;
  56                 execvp("git-rev-list", argv);
  57                 die("git-upload-pack: unable to exec git-rev-list");
  58         }
  59         dup2(fd[0], 0);
  60         close(fd[0]);
  61         close(fd[1]);
  62         execlp("git-pack-objects", "git-pack-objects", "--stdout", NULL);
  63         die("git-upload-pack: unable to exec git-pack-objects");
  64 }
  65
  66 static int got_sha1(char *hex, unsigned char *sha1)
  67 {
  68         int nr;
  69         if (get_sha1_hex(hex, sha1))
  70                 die("git-upload-pack: expected SHA1 object, got '%s'", hex);
  71         if (!has_sha1_file(sha1))
  72                 return 0;
  73         nr = nr_has;
  74         if (nr < MAX_HAS) {
  75                 memcpy(has_sha1[nr], sha1, 20);
  76                 nr_has = nr+1;
  77         }
  78         return 1;
  79 }
  80
  81 static int get_common_commits(void)
  82 {
  83         static char line[1000];
  84         unsigned char sha1[20];
  85         int len;
  86
  87         for(;;) {
  88                 len = packet_read_line(0, line, sizeof(line));
  89
  90                 if (!len) {
  91                         packet_write(1, "NAK\n");
  92                         continue;
  93                 }
  94                 len = strip(line, len);
  95                 if (!strncmp(line, "have ", 5)) {
  96                         if (got_sha1(line+5, sha1)) {
  97                                 packet_write(1, "ACK %s\n", sha1_to_hex(sha1));
  98                                 break;
  99                         }
 100                         continue;
 101                 }
 102                 if (!strcmp(line, "done")) {
 103                         packet_write(1, "NAK\n");
 104                         return -1;
 105                 }
 106                 die("git-upload-pack: expected SHA1 list, got '%s'", line);
 107         }
 108
 109         for (;;) {
 110                 len = packet_read_line(0, line, sizeof(line));
 111                 if (!len)
 112                         continue;
 113                 len = strip(line, len);
 114                 if (!strncmp(line, "have ", 5)) {
 115                         got_sha1(line+5, sha1);
 116                         continue;
 117                 }
 118                 if (!strcmp(line, "done"))
 119                         break;
 120                 die("git-upload-pack: expected SHA1 list, got '%s'", line);
 121         }
 122         return 0;
 123 }
 124
 125 static int receive_needs(void)
 126 {
 127         static char line[1000];
 128         int len, needs;
 129
 130         needs = 0;
 131         for (;;) {
 132                 len = packet_read_line(0, line, sizeof(line));
 133                 if (!len)
 134                         return needs;
 135
 136                 /*
 137                  * This is purely theoretical right now: git-fetch-pack only
 138                  * ever asks for a single HEAD
 139                  */
 140                 if (needs >= MAX_NEEDS)
 141                         die("I'm only doing a max of %d requests", MAX_NEEDS);
 142                 if (strncmp("want ", line, 5) || get_sha1_hex(line+5, needs_sha1[needs]))
 143                         die("git-upload-pack: protocol error, expected to get sha, not '%s'", line);
 144                 needs++;
 145         }
 146 }
 147
 148 static int send_ref(const char *refname, const unsigned char *sha1)
 149 {
 150         packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname);
 151         return 0;
 152 }
 153
 154 static int upload_pack(void)
 155 {
 156         head_ref(send_ref);
 157         for_each_ref(send_ref);
 158         packet_flush(1);
 159         nr_needs = receive_needs();
 160         if (!nr_needs)
 161                 return 0;
 162         get_common_commits();
 163         create_pack_file();
 164         return 0;
 165 }
 166
 167 int main(int argc, char **argv)
 168 {
 169         const char *dir;
 170         if (argc != 2)
 171                 usage(upload_pack_usage);
 172         dir = argv[1];
 173         if (chdir(dir))
 174                 die("git-upload-pack unable to chdir to %s", dir);
 175         chdir(".git");
 176         if (access("objects", X_OK) || access("refs", X_OK))
 177                 die("git-upload-pack: %s doesn't seem to be a git archive", dir);
 178         setenv("GIT_DIR", ".", 1);
 179         upload_pack();
 180         return 0;
 181 }