push: the beginning of "git push --signed"

diff --git a/send-pack.c b/send-pack.c
index bb13599c33f2cbf423bd0f4d4c1615364f0cb859..ef93f33aa5cacfb1713bbe6e9507dbae79c5eda2 100644 (file)
--- a/send-pack.c
+++ b/send-pack.c
@@ -11,6 +11,7 @@
 #include "transport.h"
 #include "version.h"
 #include "sha1-array.h"
+#include "gpg-interface.h"
 
 static int feed_object(const unsigned char *sha1, int fd, int negative)
 {
@@ -210,6 +211,64 @@ static int ref_update_to_be_sent(const struct ref *ref, const struct send_pack_a
        }
 }
 
+/*
+ * the beginning of the next line, or the end of buffer.
+ *
+ * NEEDSWORK: perhaps move this to git-compat-util.h or somewhere and
+ * convert many similar uses found by "git grep -A4 memchr".
+ */
+static const char *next_line(const char *line, size_t len)
+{
+       const char *nl = memchr(line, '\n', len);
+       if (!nl)
+               return line + len; /* incomplete line */
+       return nl + 1;
+}
+
+static void generate_push_cert(struct strbuf *req_buf,
+                              const struct ref *remote_refs,
+                              struct send_pack_args *args)
+{
+       const struct ref *ref;
+       char stamp[60];
+       char *signing_key = xstrdup(get_signing_key());
+       const char *cp, *np;
+       struct strbuf cert = STRBUF_INIT;
+       int update_seen = 0;
+
+       datestamp(stamp, sizeof(stamp));
+       strbuf_addf(&cert, "certificate version 0.1\n");
+       strbuf_addf(&cert, "pusher %s %s\n", signing_key, stamp);
+       strbuf_addstr(&cert, "\n");
+
+       for (ref = remote_refs; ref; ref = ref->next) {
+               if (!ref_update_to_be_sent(ref, args))
+                       continue;
+               update_seen = 1;
+               strbuf_addf(&cert, "%s %s %s\n",
+                           sha1_to_hex(ref->old_sha1),
+                           sha1_to_hex(ref->new_sha1),
+                           ref->name);
+       }
+       if (!update_seen)
+               goto free_return;
+
+       if (sign_buffer(&cert, &cert, signing_key))
+               die(_("failed to sign the push certificate"));
+
+       packet_buf_write(req_buf, "push-cert\n");
+       for (cp = cert.buf; cp < cert.buf + cert.len; cp = np) {
+               np = next_line(cp, cert.buf + cert.len - cp);
+               packet_buf_write(req_buf,
+                                "%.*s", (int)(np - cp), cp);
+       }
+       packet_buf_write(req_buf, "push-cert-end\n");
+
+free_return:
+       free(signing_key);
+       strbuf_release(&cert);
+}
+
 int send_pack(struct send_pack_args *args,
              int fd[], struct child_process *conn,
              struct ref *remote_refs,
@@ -245,6 +304,8 @@ int send_pack(struct send_pack_args *args,
                agent_supported = 1;
        if (server_supports("no-thin"))
                args->use_thin_pack = 0;
+       if (args->push_cert && !server_supports("push-cert"))
+               die(_("the receiving end does not support --signed push"));
 
        if (!remote_refs) {
                fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
@@ -273,6 +334,9 @@ int send_pack(struct send_pack_args *args,
        if (!args->dry_run)
                advertise_shallow_grafts_buf(&req_buf);
 
+       if (!args->dry_run && args->push_cert)
+               generate_push_cert(&req_buf, remote_refs, args);
+
        /*
         * Clear the status for each ref and see if we need to send
         * the pack data.