fetch-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 fetch_pack_usage[] = "git-fetch-pack [-q] [--exec=upload-pack] [host:]directory [heads]* < mycommitlist";
   8 static const char *exec = "git-upload-pack";
   9
  10 static int find_common(int fd[2], unsigned char *result_sha1, unsigned char *remote)
  11 {
  12         static char line[1000];
  13         int count = 0, flushes = 0, retval;
  14         FILE *revs;
  15
  16         revs = popen("git-rev-list $(git-rev-parse --all)", "r");
  17         if (!revs)
  18                 die("unable to run 'git-rev-list'");
  19         packet_write(fd[1], "want %s\n", sha1_to_hex(remote));
  20         packet_flush(fd[1]);
  21         flushes = 1;
  22         retval = -1;
  23         while (fgets(line, sizeof(line), revs) != NULL) {
  24                 unsigned char sha1[20];
  25                 if (get_sha1_hex(line, sha1))
  26                         die("git-fetch-pack: expected object name, got crud");
  27                 packet_write(fd[1], "have %s\n", sha1_to_hex(sha1));
  28                 if (!(31 & ++count)) {
  29                         packet_flush(fd[1]);
  30                         flushes++;
  31
  32                         /*
  33                          * We keep one window "ahead" of the other side, and
  34                          * will wait for an ACK only on the next one
  35                          */
  36                         if (count == 32)
  37                                 continue;
  38                         if (get_ack(fd[0], result_sha1)) {
  39                                 flushes = 0;
  40                                 retval = 0;
  41                                 break;
  42                         }
  43                         flushes--;
  44                 }
  45         }
  46         pclose(revs);
  47         packet_write(fd[1], "done\n");
  48         while (flushes) {
  49                 flushes--;
  50                 if (get_ack(fd[0], result_sha1))
  51                         return 0;
  52         }
  53         return retval;
  54 }
  55
  56 static int get_remote_heads(int fd, int nr_match, char **match, unsigned char *result)
  57 {
  58         int count = 0;
  59
  60         for (;;) {
  61                 static char line[1000];
  62                 unsigned char sha1[20];
  63                 char *refname;
  64                 int len;
  65
  66                 len = packet_read_line(fd, line, sizeof(line));
  67                 if (!len)
  68                         break;
  69                 if (line[len-1] == '\n')
  70                         line[--len] = 0;
  71                 if (len < 42 || get_sha1_hex(line, sha1))
  72                         die("git-fetch-pack: protocol error - expected ref descriptor, got '%s'", line);
  73                 refname = line+41;
  74                 if (nr_match && !path_match(refname, nr_match, match))
  75                         continue;
  76                 count++;
  77                 memcpy(result, sha1, 20);
  78         }
  79         return count;
  80 }
  81
  82 static int fetch_pack(int fd[2], int nr_match, char **match)
  83 {
  84         unsigned char sha1[20], remote[20];
  85         int heads, status;
  86         pid_t pid;
  87
  88         heads = get_remote_heads(fd[0], nr_match, match, remote);
  89         if (heads != 1) {
  90                 packet_flush(fd[1]);
  91                 die(heads ? "multiple remote heads" : "no matching remote head");
  92         }
  93         if (find_common(fd, sha1, remote) < 0)
  94                 die("git-fetch-pack: no common commits");
  95         pid = fork();
  96         if (pid < 0)
  97                 die("git-fetch-pack: unable to fork off git-unpack-objects");
  98         if (!pid) {
  99                 dup2(fd[0], 0);
 100                 close(fd[0]);
 101                 close(fd[1]);
 102                 execlp("git-unpack-objects", "git-unpack-objects",
 103                        quiet ? "-q" : NULL, NULL);
 104                 die("git-unpack-objects exec failed");
 105         }
 106         close(fd[0]);
 107         close(fd[1]);
 108         while (waitpid(pid, &status, 0) < 0) {
 109                 if (errno != EINTR)
 110                         die("waiting for git-unpack-objects: %s", strerror(errno));
 111         }
 112         if (WIFEXITED(status)) {
 113                 int code = WEXITSTATUS(status);
 114                 if (code)
 115                         die("git-unpack-objects died with error code %d", code);
 116                 puts(sha1_to_hex(remote));
 117                 return 0;
 118         }
 119         if (WIFSIGNALED(status)) {
 120                 int sig = WTERMSIG(status);
 121                 die("git-unpack-objects died of signal %d", sig);
 122         }
 123         die("Sherlock Holmes! git-unpack-objects died of unnatural causes %d!", status);
 124 }
 125
 126 int main(int argc, char **argv)
 127 {
 128         int i, ret, nr_heads;
 129         char *dest = NULL, **heads;
 130         int fd[2];
 131         pid_t pid;
 132
 133         nr_heads = 0;
 134         heads = NULL;
 135         for (i = 1; i < argc; i++) {
 136                 char *arg = argv[i];
 137
 138                 if (*arg == '-') {
 139                         if (!strncmp("--exec=", arg, 7)) {
 140                                 exec = arg + 7;
 141                                 continue;
 142                         }
 143                         usage(fetch_pack_usage);
 144                 }
 145                 dest = arg;
 146                 heads = argv + i + 1;
 147                 nr_heads = argc - i - 1;
 148                 break;
 149         }
 150         if (!dest)
 151                 usage(fetch_pack_usage);
 152         pid = git_connect(fd, dest, exec);
 153         if (pid < 0)
 154                 return 1;
 155         ret = fetch_pack(fd, nr_heads, heads);
 156         close(fd[0]);
 157         close(fd[1]);
 158         finish_connect(pid);
 159         return ret;
 160 }