root/send-pack.c

DEFINITIONS

1. option_parse_push_signed
2. feed_object
3. pack_objects
4. receive_status
5. sideband_demux
6. advertise_shallow_grafts_cb
7. advertise_shallow_grafts_buf
8. check_to_send_update
9. next_line
10. generate_push_cert
11. atomic_push_failure
12. reject_invalid_nonce
13. send_pack

#include "builtin.h"
#include "commit.h"
#include "refs.h"
#include "pkt-line.h"
#include "sideband.h"
#include "run-command.h"
#include "remote.h"
#include "connect.h"
#include "send-pack.h"
#include "quote.h"
#include "transport.h"
#include "version.h"
#include "sha1-array.h"
#include "gpg-interface.h"
#include "cache.h"

int option_parse_push_signed(const struct option *opt,
                             const char *arg, int unset)
{
        if (unset) {
                *(int *)(opt->value) = SEND_PACK_PUSH_CERT_NEVER;
                return 0;
        }
        switch (git_parse_maybe_bool(arg)) {
        case 1:
                *(int *)(opt->value) = SEND_PACK_PUSH_CERT_ALWAYS;
                return 0;
        case 0:
                *(int *)(opt->value) = SEND_PACK_PUSH_CERT_NEVER;
                return 0;
        }
        if (!strcasecmp("if-asked", arg)) {
                *(int *)(opt->value) = SEND_PACK_PUSH_CERT_IF_ASKED;
                return 0;
        }
        die("bad %s argument: %s", opt->long_name, arg);
}

static int feed_object(const unsigned char *sha1, int fd, int negative)
{
        char buf[42];

        if (negative && !has_sha1_file(sha1))
                return 1;

        memcpy(buf + negative, sha1_to_hex(sha1), 40);
        if (negative)
                buf[0] = '^';
        buf[40 + negative] = '\n';
        return write_or_whine(fd, buf, 41 + negative, "send-pack: send refs");
}

/*
 * Make a pack stream and spit it out into file descriptor fd
 */
static int pack_objects(int fd, struct ref *refs, struct sha1_array *extra, struct send_pack_args *args)
{
        /*
         * The child becomes pack-objects --revs; we feed
         * the revision parameters to it via its stdin and
         * let its stdout go back to the other end.
         */
        const char *argv[] = {
                "pack-objects",
                "--all-progress-implied",
                "--revs",
                "--stdout",
                NULL,
                NULL,
                NULL,
                NULL,
                NULL,
                NULL,
        };
        struct child_process po = CHILD_PROCESS_INIT;
        int i;

        i = 4;
        if (args->use_thin_pack)
                argv[i++] = "--thin";
        if (args->use_ofs_delta)
                argv[i++] = "--delta-base-offset";
        if (args->quiet || !args->progress)
                argv[i++] = "-q";
        if (args->progress)
                argv[i++] = "--progress";
        if (is_repository_shallow())
                argv[i++] = "--shallow";
        po.argv = argv;
        po.in = -1;
        po.out = args->stateless_rpc ? -1 : fd;
        po.git_cmd = 1;
        if (start_command(&po))
                die_errno("git pack-objects failed");

        /*
         * We feed the pack-objects we just spawned with revision
         * parameters by writing to the pipe.
         */
        for (i = 0; i < extra->nr; i++)
                if (!feed_object(extra->sha1[i], po.in, 1))
                        break;

        while (refs) {
                if (!is_null_sha1(refs->old_sha1) &&
                    !feed_object(refs->old_sha1, po.in, 1))
                        break;
                if (!is_null_sha1(refs->new_sha1) &&
                    !feed_object(refs->new_sha1, po.in, 0))
                        break;
                refs = refs->next;
        }

        close(po.in);

        if (args->stateless_rpc) {
                char *buf = xmalloc(LARGE_PACKET_MAX);
                while (1) {
                        ssize_t n = xread(po.out, buf, LARGE_PACKET_MAX);
                        if (n <= 0)
                                break;
                        send_sideband(fd, -1, buf, n, LARGE_PACKET_MAX);
                }
                free(buf);
                close(po.out);
                po.out = -1;
        }

        if (finish_command(&po))
                return -1;
        return 0;
}

static int receive_status(int in, struct ref *refs)
{
        struct ref *hint;
        int ret = 0;
        char *line = packet_read_line(in, NULL);
        if (!starts_with(line, "unpack "))
                return error("did not receive remote status");
        if (strcmp(line, "unpack ok")) {
                error("unpack failed: %s", line + 7);
                ret = -1;
        }
        hint = NULL;
        while (1) {
                char *refname;
                char *msg;
                line = packet_read_line(in, NULL);
                if (!line)
                        break;
                if (!starts_with(line, "ok ") && !starts_with(line, "ng ")) {
                        error("invalid ref status from remote: %s", line);
                        ret = -1;
                        break;
                }

                refname = line + 3;
                msg = strchr(refname, ' ');
                if (msg)
                        *msg++ = '\0';

                /* first try searching at our hint, falling back to all refs */
                if (hint)
                        hint = find_ref_by_name(hint, refname);
                if (!hint)
                        hint = find_ref_by_name(refs, refname);
                if (!hint) {
                        warning("remote reported status on unknown ref: %s",
                                        refname);
                        continue;
                }
                if (hint->status != REF_STATUS_EXPECTING_REPORT) {
                        warning("remote reported status on unexpected ref: %s",
                                        refname);
                        continue;
                }

                if (line[0] == 'o' && line[1] == 'k')
                        hint->status = REF_STATUS_OK;
                else {
                        hint->status = REF_STATUS_REMOTE_REJECT;
                        ret = -1;
                }
                if (msg)
                        hint->remote_status = xstrdup(msg);
                /* start our next search from the next ref */
                hint = hint->next;
        }
        return ret;
}

static int sideband_demux(int in, int out, void *data)
{
        int *fd = data, ret;
#ifdef NO_PTHREADS
        close(fd[1]);
#endif
        ret = recv_sideband("send-pack", fd[0], out);
        close(out);
        return ret;
}

static int advertise_shallow_grafts_cb(const struct commit_graft *graft, void *cb)
{
        struct strbuf *sb = cb;
        if (graft->nr_parent == -1)
                packet_buf_write(sb, "shallow %s\n", oid_to_hex(&graft->oid));
        return 0;
}

static void advertise_shallow_grafts_buf(struct strbuf *sb)
{
        if (!is_repository_shallow())
                return;
        for_each_commit_graft(advertise_shallow_grafts_cb, sb);
}

#define CHECK_REF_NO_PUSH -1
#define CHECK_REF_STATUS_REJECTED -2
#define CHECK_REF_UPTODATE -3
static int check_to_send_update(const struct ref *ref, const struct send_pack_args *args)
{
        if (!ref->peer_ref && !args->send_mirror)
                return CHECK_REF_NO_PUSH;

        /* Check for statuses set by set_ref_status_for_push() */
        switch (ref->status) {
        case REF_STATUS_REJECT_NONFASTFORWARD:
        case REF_STATUS_REJECT_ALREADY_EXISTS:
        case REF_STATUS_REJECT_FETCH_FIRST:
        case REF_STATUS_REJECT_NEEDS_FORCE:
        case REF_STATUS_REJECT_STALE:
        case REF_STATUS_REJECT_NODELETE:
                return CHECK_REF_STATUS_REJECTED;
        case REF_STATUS_UPTODATE:
                return CHECK_REF_UPTODATE;
        default:
                return 0;
        }
}

/*
 * 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 int generate_push_cert(struct strbuf *req_buf,
                              const struct ref *remote_refs,
                              struct send_pack_args *args,
                              const char *cap_string,
                              const char *push_cert_nonce)
{
        const struct ref *ref;
        char *signing_key = xstrdup(get_signing_key());
        const char *cp, *np;
        struct strbuf cert = STRBUF_INIT;
        int update_seen = 0;

        strbuf_addf(&cert, "certificate version 0.1\n");
        strbuf_addf(&cert, "pusher %s ", signing_key);
        datestamp(&cert);
        strbuf_addch(&cert, '\n');
        if (args->url && *args->url) {
                char *anon_url = transport_anonymize_url(args->url);
                strbuf_addf(&cert, "pushee %s\n", anon_url);
                free(anon_url);
        }
        if (push_cert_nonce[0])
                strbuf_addf(&cert, "nonce %s\n", push_cert_nonce);
        strbuf_addstr(&cert, "\n");

        for (ref = remote_refs; ref; ref = ref->next) {
                if (check_to_send_update(ref, args) < 0)
                        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%c%s", 0, cap_string);
        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);
        return update_seen;
}


static int atomic_push_failure(struct send_pack_args *args,
                               struct ref *remote_refs,
                               struct ref *failing_ref)
{
        struct ref *ref;
        /* Mark other refs as failed */
        for (ref = remote_refs; ref; ref = ref->next) {
                if (!ref->peer_ref && !args->send_mirror)
                        continue;

                switch (ref->status) {
                case REF_STATUS_EXPECTING_REPORT:
                        ref->status = REF_STATUS_ATOMIC_PUSH_FAILED;
                        continue;
                default:
                        break; /* do nothing */
                }
        }
        return error("atomic push failed for ref %s. status: %d\n",
                     failing_ref->name, failing_ref->status);
}

#define NONCE_LEN_LIMIT 256

static void reject_invalid_nonce(const char *nonce, int len)
{
        int i = 0;

        if (NONCE_LEN_LIMIT <= len)
                die("the receiving end asked to sign an invalid nonce <%.*s>",
                    len, nonce);

        for (i = 0; i < len; i++) {
                int ch = nonce[i] & 0xFF;
                if (isalnum(ch) ||
                    ch == '-' || ch == '.' ||
                    ch == '/' || ch == '+' ||
                    ch == '=' || ch == '_')
                        continue;
                die("the receiving end asked to sign an invalid nonce <%.*s>",
                    len, nonce);
        }
}

int send_pack(struct send_pack_args *args,
              int fd[], struct child_process *conn,
              struct ref *remote_refs,
              struct sha1_array *extra_have)
{
        int in = fd[0];
        int out = fd[1];
        struct strbuf req_buf = STRBUF_INIT;
        struct strbuf cap_buf = STRBUF_INIT;
        struct ref *ref;
        int need_pack_data = 0;
        int allow_deleting_refs = 0;
        int status_report = 0;
        int use_sideband = 0;
        int quiet_supported = 0;
        int agent_supported = 0;
        int use_atomic = 0;
        int atomic_supported = 0;
        unsigned cmds_sent = 0;
        int ret;
        struct async demux;
        const char *push_cert_nonce = NULL;

        /* Does the other end support the reporting? */
        if (server_supports("report-status"))
                status_report = 1;
        if (server_supports("delete-refs"))
                allow_deleting_refs = 1;
        if (server_supports("ofs-delta"))
                args->use_ofs_delta = 1;
        if (server_supports("side-band-64k"))
                use_sideband = 1;
        if (server_supports("quiet"))
                quiet_supported = 1;
        if (server_supports("agent"))
                agent_supported = 1;
        if (server_supports("no-thin"))
                args->use_thin_pack = 0;
        if (server_supports("atomic"))
                atomic_supported = 1;

        if (args->push_cert != SEND_PACK_PUSH_CERT_NEVER) {
                int len;
                push_cert_nonce = server_feature_value("push-cert", &len);
                if (push_cert_nonce) {
                        reject_invalid_nonce(push_cert_nonce, len);
                        push_cert_nonce = xmemdupz(push_cert_nonce, len);
                } else if (args->push_cert == SEND_PACK_PUSH_CERT_ALWAYS) {
                        die(_("the receiving end does not support --signed push"));
                } else if (args->push_cert == SEND_PACK_PUSH_CERT_IF_ASKED) {
                        warning(_("not sending a push certificate since the"
                                  " receiving end does not support --signed"
                                  " push"));
                }
        }

        if (!remote_refs) {
                fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
                        "Perhaps you should specify a branch such as 'master'.\n");
                return 0;
        }
        if (args->atomic && !atomic_supported)
                die(_("the receiving end does not support --atomic push"));

        use_atomic = atomic_supported && args->atomic;

        if (status_report)
                strbuf_addstr(&cap_buf, " report-status");
        if (use_sideband)
                strbuf_addstr(&cap_buf, " side-band-64k");
        if (quiet_supported && (args->quiet || !args->progress))
                strbuf_addstr(&cap_buf, " quiet");
        if (use_atomic)
                strbuf_addstr(&cap_buf, " atomic");
        if (agent_supported)
                strbuf_addf(&cap_buf, " agent=%s", git_user_agent_sanitized());

        /*
         * NEEDSWORK: why does delete-refs have to be so specific to
         * send-pack machinery that set_ref_status_for_push() cannot
         * set this bit for us???
         */
        for (ref = remote_refs; ref; ref = ref->next)
                if (ref->deletion && !allow_deleting_refs)
                        ref->status = REF_STATUS_REJECT_NODELETE;

        if (!args->dry_run)
                advertise_shallow_grafts_buf(&req_buf);

        if (!args->dry_run && push_cert_nonce)
                cmds_sent = generate_push_cert(&req_buf, remote_refs, args,
                                               cap_buf.buf, push_cert_nonce);

        /*
         * Clear the status for each ref and see if we need to send
         * the pack data.
         */
        for (ref = remote_refs; ref; ref = ref->next) {
                switch (check_to_send_update(ref, args)) {
                case 0: /* no error */
                        break;
                case CHECK_REF_STATUS_REJECTED:
                        /*
                         * When we know the server would reject a ref update if
                         * we were to send it and we're trying to send the refs
                         * atomically, abort the whole operation.
                         */
                        if (use_atomic)
                                return atomic_push_failure(args, remote_refs, ref);
                        /* Fallthrough for non atomic case. */
                default:
                        continue;
                }
                if (!ref->deletion)
                        need_pack_data = 1;

                if (args->dry_run || !status_report)
                        ref->status = REF_STATUS_OK;
                else
                        ref->status = REF_STATUS_EXPECTING_REPORT;
        }

        /*
         * Finally, tell the other end!
         */
        for (ref = remote_refs; ref; ref = ref->next) {
                char *old_hex, *new_hex;

                if (args->dry_run || push_cert_nonce)
                        continue;

                if (check_to_send_update(ref, args) < 0)
                        continue;

                old_hex = sha1_to_hex(ref->old_sha1);
                new_hex = sha1_to_hex(ref->new_sha1);
                if (!cmds_sent) {
                        packet_buf_write(&req_buf,
                                         "%s %s %s%c%s",
                                         old_hex, new_hex, ref->name, 0,
                                         cap_buf.buf);
                        cmds_sent = 1;
                } else {
                        packet_buf_write(&req_buf, "%s %s %s",
                                         old_hex, new_hex, ref->name);
                }
        }

        if (args->stateless_rpc) {
                if (!args->dry_run && (cmds_sent || is_repository_shallow())) {
                        packet_buf_flush(&req_buf);
                        send_sideband(out, -1, req_buf.buf, req_buf.len, LARGE_PACKET_MAX);
                }
        } else {
                write_or_die(out, req_buf.buf, req_buf.len);
                packet_flush(out);
        }
        strbuf_release(&req_buf);
        strbuf_release(&cap_buf);

        if (use_sideband && cmds_sent) {
                memset(&demux, 0, sizeof(demux));
                demux.proc = sideband_demux;
                demux.data = fd;
                demux.out = -1;
                if (start_async(&demux))
                        die("send-pack: unable to fork off sideband demultiplexer");
                in = demux.out;
        }

        if (need_pack_data && cmds_sent) {
                if (pack_objects(out, remote_refs, extra_have, args) < 0) {
                        for (ref = remote_refs; ref; ref = ref->next)
                                ref->status = REF_STATUS_NONE;
                        if (args->stateless_rpc)
                                close(out);
                        if (git_connection_is_socket(conn))
                                shutdown(fd[0], SHUT_WR);
                        if (use_sideband)
                                finish_async(&demux);
                        fd[1] = -1;
                        return -1;
                }
                if (!args->stateless_rpc)
                        /* Closed by pack_objects() via start_command() */
                        fd[1] = -1;
        }
        if (args->stateless_rpc && cmds_sent)
                packet_flush(out);

        if (status_report && cmds_sent)
                ret = receive_status(in, remote_refs);
        else
                ret = 0;
        if (args->stateless_rpc)
                packet_flush(out);

        if (use_sideband && cmds_sent) {
                if (finish_async(&demux)) {
                        error("error in sideband demultiplexer");
                        ret = -1;
                }
                close(demux.out);
        }

        if (ret < 0)
                return ret;

        if (args->porcelain)
                return 0;

        for (ref = remote_refs; ref; ref = ref->next) {
                switch (ref->status) {
                case REF_STATUS_NONE:
                case REF_STATUS_UPTODATE:
                case REF_STATUS_OK:
                        break;
                default:
                        return -1;
                }
        }
        return 0;
}