fetch-pack.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "pkt-line.h"
   4 #include <sys/wait.h>
   5
   6 static const char fetch_pack_usage[] = "git-fetch-pack [host:]directory [heads]* < mycommitlist";
   7 static const char *exec = "git-upload-pack";
   8
   9 static int find_common(int fd[2], unsigned char *result_sha1, unsigned char *remote)
  10 {
  11         static char line[1000];
  12         int count = 0, flushes = 0, retval;
  13         FILE *revs;
  14
  15         revs = popen("git-rev-list $(git-rev-parse --all)", "r");
  16         if (!revs)
  17                 die("unable to run 'git-rev-list'");
  18         packet_write(fd[1], "want %s\n", sha1_to_hex(remote));
  19         packet_flush(fd[1]);
  20         flushes = 1;
  21         retval = -1;
  22         while (fgets(line, sizeof(line), revs) != NULL) {
  23                 unsigned char sha1[20];
  24                 if (get_sha1_hex(line, sha1))
  25                         die("git-fetch-pack: expected object name, got crud");
  26                 packet_write(fd[1], "have %s\n", sha1_to_hex(sha1));
  27                 if (!(31 & ++count)) {
  28                         packet_flush(fd[1]);
  29                         flushes++;
  30
  31                         /*
  32                          * We keep one window "ahead" of the other side, and
  33                          * will wait for an ACK only on the next one
  34                          */
  35                         if (count == 32)
  36                                 continue;
  37                         if (get_ack(fd[0], result_sha1)) {
  38                                 flushes = 0;
  39                                 retval = 0;
  40                                 break;
  41                         }
  42                         flushes--;
  43                 }
  44         }
  45         pclose(revs);
  46         packet_write(fd[1], "done\n");
  47         while (flushes) {
  48                 flushes--;
  49                 if (get_ack(fd[0], result_sha1))
  50                         return 0;
  51         }
  52         return retval;
  53 }
  54
  55 static int get_remote_heads(int fd, int nr_match, char **match, unsigned char *result)
  56 {
  57         int count = 0;
  58
  59         for (;;) {
  60                 static char line[1000];
  61                 unsigned char sha1[20];
  62                 char *refname;
  63                 int len;
  64
  65                 len = packet_read_line(fd, line, sizeof(line));
  66                 if (!len)
  67                         break;
  68                 if (line[len-1] == '\n')
  69                         line[--len] = 0;
  70                 if (len < 42 || get_sha1_hex(line, sha1))
  71                         die("git-fetch-pack: protocol error - expected ref descriptor, got '%s'", line);
  72                 refname = line+41;
  73                 if (nr_match && !path_match(refname, nr_match, match))
  74                         continue;
  75                 count++;
  76                 memcpy(result, sha1, 20);
  77         }
  78         return count;
  79 }
  80
  81 static int fetch_pack(int fd[2], int nr_match, char **match)
  82 {
  83         unsigned char sha1[20], remote[20];
  84         int heads, status;
  85         pid_t pid;
  86
  87         heads = get_remote_heads(fd[0], nr_match, match, remote);
  88         if (heads != 1) {
  89                 packet_flush(fd[1]);
  90                 die(heads ? "multiple remote heads" : "no matching remote head");
  91         }
  92         if (find_common(fd, sha1, remote) < 0)
  93                 die("git-fetch-pack: no common commits");
  94         pid = fork();
  95         if (pid < 0)
  96                 die("git-fetch-pack: unable to fork off git-unpack-objects");
  97         if (!pid) {
  98                 dup2(fd[0], 0);
  99                 close(fd[0]);
 100                 close(fd[1]);
 101                 execlp("git-unpack-objects", "git-unpack-objects", NULL);
 102                 die("git-unpack-objects exec failed");
 103         }
 104         close(fd[0]);
 105         close(fd[1]);
 106         while (waitpid(pid, &status, 0) < 0) {
 107                 if (errno != EINTR)
 108                         die("waiting for git-unpack-objects: %s", strerror(errno));
 109         }
 110         if (WIFEXITED(status)) {
 111                 int code = WEXITSTATUS(status);
 112                 if (code)
 113                         die("git-unpack-objects died with error code %d", code);
 114                 puts(sha1_to_hex(remote));
 115                 return 0;
 116         }
 117         if (WIFSIGNALED(status)) {
 118                 int sig = WTERMSIG(status);
 119                 die("git-unpack-objects died of signal %d", sig);
 120         }
 121         die("Sherlock Holmes! git-unpack-objects died of unnatural causes %d!", status);
 122 }
 123
 124 int main(int argc, char **argv)
 125 {
 126         int i, ret, nr_heads;
 127         char *dest = NULL, **heads;
 128         int fd[2];
 129         pid_t pid;
 130
 131         nr_heads = 0;
 132         heads = NULL;
 133         for (i = 1; i < argc; i++) {
 134                 char *arg = argv[i];
 135
 136                 if (*arg == '-') {
 137                         /* Arguments go here */
 138                         usage(fetch_pack_usage);
 139                 }
 140                 dest = arg;
 141                 heads = argv + i + 1;
 142                 nr_heads = argc - i - 1;
 143                 break;
 144         }
 145         if (!dest)
 146                 usage(fetch_pack_usage);
 147         pid = git_connect(fd, dest, exec);
 148         if (pid < 0)
 149                 return 1;
 150         ret = fetch_pack(fd, nr_heads, heads);
 151         close(fd[0]);
 152         close(fd[1]);
 153         finish_connect(pid);
 154         return ret;
 155 }