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a85b377d04
git/builtin/receive-pack.c
Junio C Hamano a85b377d04 push: the beginning of "git push --signed" 
While signed tags and commits assert that the objects thusly signed
came from you, who signed these objects, there is not a good way to
assert that you wanted to have a particular object at the tip of a
particular branch.  My signing v2.0.1 tag only means I want to call
the version v2.0.1, and it does not mean I want to push it out to my
'master' branch---it is likely that I only want it in 'maint', so
the signature on the object alone is insufficient.

The only assurance to you that 'maint' points at what I wanted to
place there comes from your trust on the hosting site and my
authentication with it, which cannot easily audited later.

Introduce a mechanism that allows you to sign a "push certificate"
(for the lack of better name) every time you push, asserting that
what object you are pushing to update which ref that used to point
at what other object.  Think of it as a cryptographic protection for
ref updates, similar to signed tags/commits but working on an
orthogonal axis.

The basic flow based on this mechanism goes like this:

 1. You push out your work with "git push --signed".

 2. The sending side learns where the remote refs are as usual,
    together with what protocol extension the receiving end
    supports.  If the receiving end does not advertise the protocol
    extension "push-cert", an attempt to "git push --signed" fails.

    Otherwise, a text file, that looks like the following, is
    prepared in core:

	certificate version 0.1
	pusher Junio C Hamano <gitster@pobox.com> 1315427886 -0700

	7339ca65... 21580ecb... refs/heads/master
	3793ac56... 12850bec... refs/heads/next

    The file begins with a few header lines, which may grow as we
    gain more experience.  The 'pusher' header records the name of
    the signer (the value of user.signingkey configuration variable,
    falling back to GIT_COMMITTER_{NAME|EMAIL}) and the time of the
    certificate generation.  After the header, a blank line follows,
    followed by a copy of the protocol message lines.

    Each line shows the old and the new object name at the tip of
    the ref this push tries to update, in the way identical to how
    the underlying "git push" protocol exchange tells the ref
    updates to the receiving end (by recording the "old" object
    name, the push certificate also protects against replaying).  It
    is expected that new command packet types other than the
    old-new-refname kind will be included in push certificate in the
    same way as would appear in the plain vanilla command packets in
    unsigned pushes.

    The user then is asked to sign this push certificate using GPG,
    formatted in a way similar to how signed tag objects are signed,
    and the result is sent to the other side (i.e. receive-pack).

    In the protocol exchange, this step comes immediately before the
    sender tells what the result of the push should be, which in
    turn comes before it sends the pack data.

 3. When the receiving end sees a push certificate, the certificate
    is written out as a blob.  The pre-receive hook can learn about
    the certificate by checking GIT_PUSH_CERT environment variable,
    which, if present, tells the object name of this blob, and make
    the decision to allow or reject this push.  Additionally, the
    post-receive hook can also look at the certificate, which may be
    a good place to log all the received certificates for later
    audits.

Because a push certificate carry the same information as the usual
command packets in the protocol exchange, we can omit the latter
when a push certificate is in use and reduce the protocol overhead.
This however is not included in this patch to make it easier to
review (in other words, the series at this step should never be
released without the remainder of the series, as it implements an
interim protocol that will be incompatible with the final one).
As such, the documentation update for the protocol is left out of
this step.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-09-15 13:23:20 -07:00

1288 lines
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#include "builtin.h"
#include "pack.h"
#include "refs.h"
#include "pkt-line.h"
#include "sideband.h"
#include "run-command.h"
#include "exec_cmd.h"
#include "commit.h"
#include "object.h"
#include "remote.h"
#include "connect.h"
#include "transport.h"
#include "string-list.h"
#include "sha1-array.h"
#include "connected.h"
#include "argv-array.h"
#include "version.h"
static const char receive_pack_usage[] = "git receive-pack <git-dir>";
enum deny_action {
DENY_UNCONFIGURED,
DENY_IGNORE,
DENY_WARN,
DENY_REFUSE
};
static int deny_deletes;
static int deny_non_fast_forwards;
static enum deny_action deny_current_branch = DENY_UNCONFIGURED;
static enum deny_action deny_delete_current = DENY_UNCONFIGURED;
static int receive_fsck_objects = -1;
static int transfer_fsck_objects = -1;
static int receive_unpack_limit = -1;
static int transfer_unpack_limit = -1;
static int unpack_limit = 100;
static int report_status;
static int use_sideband;
static int quiet;
static int prefer_ofs_delta = 1;
static int auto_update_server_info;
static int auto_gc = 1;
static int fix_thin = 1;
static const char *head_name;
static void *head_name_to_free;
static int sent_capabilities;
static int shallow_update;
static const char *alt_shallow_file;
static int accept_push_cert = 1;
static struct strbuf push_cert = STRBUF_INIT;
static unsigned char push_cert_sha1[20];
static enum deny_action parse_deny_action(const char *var, const char *value)
{
if (value) {
if (!strcasecmp(value, "ignore"))
return DENY_IGNORE;
if (!strcasecmp(value, "warn"))
return DENY_WARN;
if (!strcasecmp(value, "refuse"))
return DENY_REFUSE;
}
if (git_config_bool(var, value))
return DENY_REFUSE;
return DENY_IGNORE;
}
static int receive_pack_config(const char *var, const char *value, void *cb)
{
int status = parse_hide_refs_config(var, value, "receive");
if (status)
return status;
if (strcmp(var, "receive.denydeletes") == 0) {
deny_deletes = git_config_bool(var, value);
return 0;
}
if (strcmp(var, "receive.denynonfastforwards") == 0) {
deny_non_fast_forwards = git_config_bool(var, value);
return 0;
}
if (strcmp(var, "receive.unpacklimit") == 0) {
receive_unpack_limit = git_config_int(var, value);
return 0;
}
if (strcmp(var, "transfer.unpacklimit") == 0) {
transfer_unpack_limit = git_config_int(var, value);
return 0;
}
if (strcmp(var, "receive.fsckobjects") == 0) {
receive_fsck_objects = git_config_bool(var, value);
return 0;
}
if (strcmp(var, "transfer.fsckobjects") == 0) {
transfer_fsck_objects = git_config_bool(var, value);
return 0;
}
if (!strcmp(var, "receive.denycurrentbranch")) {
deny_current_branch = parse_deny_action(var, value);
return 0;
}
if (strcmp(var, "receive.denydeletecurrent") == 0) {
deny_delete_current = parse_deny_action(var, value);
return 0;
}
if (strcmp(var, "repack.usedeltabaseoffset") == 0) {
prefer_ofs_delta = git_config_bool(var, value);
return 0;
}
if (strcmp(var, "receive.updateserverinfo") == 0) {
auto_update_server_info = git_config_bool(var, value);
return 0;
}
if (strcmp(var, "receive.autogc") == 0) {
auto_gc = git_config_bool(var, value);
return 0;
}
if (strcmp(var, "receive.shallowupdate") == 0) {
shallow_update = git_config_bool(var, value);
return 0;
}
if (strcmp(var, "receive.acceptpushcert") == 0) {
accept_push_cert = git_config_bool(var, value);
return 0;
}
return git_default_config(var, value, cb);
}
static void show_ref(const char *path, const unsigned char *sha1)
{
if (ref_is_hidden(path))
return;
if (sent_capabilities) {
packet_write(1, "%s %s\n", sha1_to_hex(sha1), path);
} else {
struct strbuf cap = STRBUF_INIT;
strbuf_addstr(&cap,
"report-status delete-refs side-band-64k quiet");
if (prefer_ofs_delta)
strbuf_addstr(&cap, " ofs-delta");
if (accept_push_cert)
strbuf_addstr(&cap, " push-cert");
strbuf_addf(&cap, " agent=%s", git_user_agent_sanitized());
packet_write(1, "%s %s%c%s\n",
sha1_to_hex(sha1), path, 0, cap.buf);
strbuf_release(&cap);
sent_capabilities = 1;
}
}
static int show_ref_cb(const char *path, const unsigned char *sha1, int flag, void *unused)
{
path = strip_namespace(path);
/*
* Advertise refs outside our current namespace as ".have"
* refs, so that the client can use them to minimize data
* transfer but will otherwise ignore them. This happens to
* cover ".have" that are thrown in by add_one_alternate_ref()
* to mark histories that are complete in our alternates as
* well.
*/
if (!path)
path = ".have";
show_ref(path, sha1);
return 0;
}
static void show_one_alternate_sha1(const unsigned char sha1[20], void *unused)
{
show_ref(".have", sha1);
}
static void collect_one_alternate_ref(const struct ref *ref, void *data)
{
struct sha1_array *sa = data;
sha1_array_append(sa, ref->old_sha1);
}
static void write_head_info(void)
{
struct sha1_array sa = SHA1_ARRAY_INIT;
for_each_alternate_ref(collect_one_alternate_ref, &sa);
sha1_array_for_each_unique(&sa, show_one_alternate_sha1, NULL);
sha1_array_clear(&sa);
for_each_ref(show_ref_cb, NULL);
if (!sent_capabilities)
show_ref("capabilities^{}", null_sha1);
advertise_shallow_grafts(1);
/* EOF */
packet_flush(1);
}
struct command {
struct command *next;
const char *error_string;
unsigned int skip_update:1,
did_not_exist:1;
int index;
unsigned char old_sha1[20];
unsigned char new_sha1[20];
char ref_name[FLEX_ARRAY]; /* more */
};
static void rp_error(const char *err, ...) __attribute__((format (printf, 1, 2)));
static void rp_warning(const char *err, ...) __attribute__((format (printf, 1, 2)));
static void report_message(const char *prefix, const char *err, va_list params)
{
int sz = strlen(prefix);
char msg[4096];
strncpy(msg, prefix, sz);
sz += vsnprintf(msg + sz, sizeof(msg) - sz, err, params);
if (sz > (sizeof(msg) - 1))
sz = sizeof(msg) - 1;
msg[sz++] = '\n';
if (use_sideband)
send_sideband(1, 2, msg, sz, use_sideband);
else
xwrite(2, msg, sz);
}
static void rp_warning(const char *err, ...)
{
va_list params;
va_start(params, err);
report_message("warning: ", err, params);
va_end(params);
}
static void rp_error(const char *err, ...)
{
va_list params;
va_start(params, err);
report_message("error: ", err, params);
va_end(params);
}
static int copy_to_sideband(int in, int out, void *arg)
{
char data[128];
while (1) {
ssize_t sz = xread(in, data, sizeof(data));
if (sz <= 0)
break;
send_sideband(1, 2, data, sz, use_sideband);
}
close(in);
return 0;
}
static void prepare_push_cert_sha1(struct child_process *proc)
{
static int already_done;
struct argv_array env = ARGV_ARRAY_INIT;
if (!push_cert.len)
return;
if (!already_done) {
already_done = 1;
if (write_sha1_file(push_cert.buf, push_cert.len, "blob", push_cert_sha1))
hashclr(push_cert_sha1);
}
if (!is_null_sha1(push_cert_sha1)) {
argv_array_pushf(&env, "GIT_PUSH_CERT=%s", sha1_to_hex(push_cert_sha1));
proc->env = env.argv;
}
}
typedef int (*feed_fn)(void *, const char **, size_t *);
static int run_and_feed_hook(const char *hook_name, feed_fn feed, void *feed_state)
{
struct child_process proc;
struct async muxer;
const char *argv[2];
int code;
argv[0] = find_hook(hook_name);
if (!argv[0])
return 0;
argv[1] = NULL;
memset(&proc, 0, sizeof(proc));
proc.argv = argv;
proc.in = -1;
proc.stdout_to_stderr = 1;
prepare_push_cert_sha1(&proc);
if (use_sideband) {
memset(&muxer, 0, sizeof(muxer));
muxer.proc = copy_to_sideband;
muxer.in = -1;
code = start_async(&muxer);
if (code)
return code;
proc.err = muxer.in;
}
code = start_command(&proc);
if (code) {
if (use_sideband)
finish_async(&muxer);
return code;
}
while (1) {
const char *buf;
size_t n;
if (feed(feed_state, &buf, &n))
break;
if (write_in_full(proc.in, buf, n) != n)
break;
}
close(proc.in);
if (use_sideband)
finish_async(&muxer);
return finish_command(&proc);
}
struct receive_hook_feed_state {
struct command *cmd;
int skip_broken;
struct strbuf buf;
};
static int feed_receive_hook(void *state_, const char **bufp, size_t *sizep)
{
struct receive_hook_feed_state *state = state_;
struct command *cmd = state->cmd;
while (cmd &&
state->skip_broken && (cmd->error_string || cmd->did_not_exist))
cmd = cmd->next;
if (!cmd)
return -1; /* EOF */
strbuf_reset(&state->buf);
strbuf_addf(&state->buf, "%s %s %s\n",
sha1_to_hex(cmd->old_sha1), sha1_to_hex(cmd->new_sha1),
cmd->ref_name);
state->cmd = cmd->next;
if (bufp) {
*bufp = state->buf.buf;
*sizep = state->buf.len;
}
return 0;
}
static int run_receive_hook(struct command *commands, const char *hook_name,
int skip_broken)
{
struct receive_hook_feed_state state;
int status;
strbuf_init(&state.buf, 0);
state.cmd = commands;
state.skip_broken = skip_broken;
if (feed_receive_hook(&state, NULL, NULL))
return 0;
state.cmd = commands;
status = run_and_feed_hook(hook_name, feed_receive_hook, &state);
strbuf_release(&state.buf);
return status;
}
static int run_update_hook(struct command *cmd)
{
const char *argv[5];
struct child_process proc;
int code;
argv[0] = find_hook("update");
if (!argv[0])
return 0;
argv[1] = cmd->ref_name;
argv[2] = sha1_to_hex(cmd->old_sha1);
argv[3] = sha1_to_hex(cmd->new_sha1);
argv[4] = NULL;
memset(&proc, 0, sizeof(proc));
proc.no_stdin = 1;
proc.stdout_to_stderr = 1;
proc.err = use_sideband ? -1 : 0;
proc.argv = argv;
code = start_command(&proc);
if (code)
return code;
if (use_sideband)
copy_to_sideband(proc.err, -1, NULL);
return finish_command(&proc);
}
static int is_ref_checked_out(const char *ref)
{
if (is_bare_repository())
return 0;
if (!head_name)
return 0;
return !strcmp(head_name, ref);
}
static char *refuse_unconfigured_deny_msg[] = {
"By default, updating the current branch in a non-bare repository",
"is denied, because it will make the index and work tree inconsistent",
"with what you pushed, and will require 'git reset --hard' to match",
"the work tree to HEAD.",
"",
"You can set 'receive.denyCurrentBranch' configuration variable to",
"'ignore' or 'warn' in the remote repository to allow pushing into",
"its current branch; however, this is not recommended unless you",
"arranged to update its work tree to match what you pushed in some",
"other way.",
"",
"To squelch this message and still keep the default behaviour, set",
"'receive.denyCurrentBranch' configuration variable to 'refuse'."
};
static void refuse_unconfigured_deny(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(refuse_unconfigured_deny_msg); i++)
rp_error("%s", refuse_unconfigured_deny_msg[i]);
}
static char *refuse_unconfigured_deny_delete_current_msg[] = {
"By default, deleting the current branch is denied, because the next",
"'git clone' won't result in any file checked out, causing confusion.",
"",
"You can set 'receive.denyDeleteCurrent' configuration variable to",
"'warn' or 'ignore' in the remote repository to allow deleting the",
"current branch, with or without a warning message.",
"",
"To squelch this message, you can set it to 'refuse'."
};
static void refuse_unconfigured_deny_delete_current(void)
{
int i;
for (i = 0;
i < ARRAY_SIZE(refuse_unconfigured_deny_delete_current_msg);
i++)
rp_error("%s", refuse_unconfigured_deny_delete_current_msg[i]);
}
static int command_singleton_iterator(void *cb_data, unsigned char sha1[20]);
static int update_shallow_ref(struct command *cmd, struct shallow_info *si)
{
static struct lock_file shallow_lock;
struct sha1_array extra = SHA1_ARRAY_INIT;
const char *alt_file;
uint32_t mask = 1 << (cmd->index % 32);
int i;
trace_printf_key(&trace_shallow,
"shallow: update_shallow_ref %s\n", cmd->ref_name);
for (i = 0; i < si->shallow->nr; i++)
if (si->used_shallow[i] &&
(si->used_shallow[i][cmd->index / 32] & mask) &&
!delayed_reachability_test(si, i))
sha1_array_append(&extra, si->shallow->sha1[i]);
setup_alternate_shallow(&shallow_lock, &alt_file, &extra);
if (check_shallow_connected(command_singleton_iterator,
0, cmd, alt_file)) {
rollback_lock_file(&shallow_lock);
sha1_array_clear(&extra);
return -1;
}
commit_lock_file(&shallow_lock);
/*
* Make sure setup_alternate_shallow() for the next ref does
* not lose these new roots..
*/
for (i = 0; i < extra.nr; i++)
register_shallow(extra.sha1[i]);
si->shallow_ref[cmd->index] = 0;
sha1_array_clear(&extra);
return 0;
}
static const char *update(struct command *cmd, struct shallow_info *si)
{
const char *name = cmd->ref_name;
struct strbuf namespaced_name_buf = STRBUF_INIT;
const char *namespaced_name;
unsigned char *old_sha1 = cmd->old_sha1;
unsigned char *new_sha1 = cmd->new_sha1;
struct ref_lock *lock;
/* only refs/... are allowed */
if (!starts_with(name, "refs/") || check_refname_format(name + 5, 0)) {
rp_error("refusing to create funny ref '%s' remotely", name);
return "funny refname";
}
strbuf_addf(&namespaced_name_buf, "%s%s", get_git_namespace(), name);
namespaced_name = strbuf_detach(&namespaced_name_buf, NULL);
if (is_ref_checked_out(namespaced_name)) {
switch (deny_current_branch) {
case DENY_IGNORE:
break;
case DENY_WARN:
rp_warning("updating the current branch");
break;
case DENY_REFUSE:
case DENY_UNCONFIGURED:
rp_error("refusing to update checked out branch: %s", name);
if (deny_current_branch == DENY_UNCONFIGURED)
refuse_unconfigured_deny();
return "branch is currently checked out";
}
}
if (!is_null_sha1(new_sha1) && !has_sha1_file(new_sha1)) {
error("unpack should have generated %s, "
"but I can't find it!", sha1_to_hex(new_sha1));
return "bad pack";
}
if (!is_null_sha1(old_sha1) && is_null_sha1(new_sha1)) {
if (deny_deletes && starts_with(name, "refs/heads/")) {
rp_error("denying ref deletion for %s", name);
return "deletion prohibited";
}
if (!strcmp(namespaced_name, head_name)) {
switch (deny_delete_current) {
case DENY_IGNORE:
break;
case DENY_WARN:
rp_warning("deleting the current branch");
break;
case DENY_REFUSE:
case DENY_UNCONFIGURED:
if (deny_delete_current == DENY_UNCONFIGURED)
refuse_unconfigured_deny_delete_current();
rp_error("refusing to delete the current branch: %s", name);
return "deletion of the current branch prohibited";
}
}
}
if (deny_non_fast_forwards && !is_null_sha1(new_sha1) &&
!is_null_sha1(old_sha1) &&
starts_with(name, "refs/heads/")) {
struct object *old_object, *new_object;
struct commit *old_commit, *new_commit;
old_object = parse_object(old_sha1);
new_object = parse_object(new_sha1);
if (!old_object || !new_object ||
old_object->type != OBJ_COMMIT ||
new_object->type != OBJ_COMMIT) {
error("bad sha1 objects for %s", name);
return "bad ref";
}
old_commit = (struct commit *)old_object;
new_commit = (struct commit *)new_object;
if (!in_merge_bases(old_commit, new_commit)) {
rp_error("denying non-fast-forward %s"
" (you should pull first)", name);
return "non-fast-forward";
}
}
if (run_update_hook(cmd)) {
rp_error("hook declined to update %s", name);
return "hook declined";
}
if (is_null_sha1(new_sha1)) {
if (!parse_object(old_sha1)) {
old_sha1 = NULL;
if (ref_exists(name)) {
rp_warning("Allowing deletion of corrupt ref.");
} else {
rp_warning("Deleting a non-existent ref.");
cmd->did_not_exist = 1;
}
}
if (delete_ref(namespaced_name, old_sha1, 0)) {
rp_error("failed to delete %s", name);
return "failed to delete";
}
return NULL; /* good */
}
else {
if (shallow_update && si->shallow_ref[cmd->index] &&
update_shallow_ref(cmd, si))
return "shallow error";
lock = lock_any_ref_for_update(namespaced_name, old_sha1,
0, NULL);
if (!lock) {
rp_error("failed to lock %s", name);
return "failed to lock";
}
if (write_ref_sha1(lock, new_sha1, "push")) {
return "failed to write"; /* error() already called */
}
return NULL; /* good */
}
}
static void run_update_post_hook(struct command *commands)
{
struct command *cmd;
int argc;
const char **argv;
struct child_process proc;
char *hook;
hook = find_hook("post-update");
for (argc = 0, cmd = commands; cmd; cmd = cmd->next) {
if (cmd->error_string || cmd->did_not_exist)
continue;
argc++;
}
if (!argc || !hook)
return;
argv = xmalloc(sizeof(*argv) * (2 + argc));
argv[0] = hook;
for (argc = 1, cmd = commands; cmd; cmd = cmd->next) {
if (cmd->error_string || cmd->did_not_exist)
continue;
argv[argc] = xstrdup(cmd->ref_name);
argc++;
}
argv[argc] = NULL;
memset(&proc, 0, sizeof(proc));
proc.no_stdin = 1;
proc.stdout_to_stderr = 1;
proc.err = use_sideband ? -1 : 0;
proc.argv = argv;
if (!start_command(&proc)) {
if (use_sideband)
copy_to_sideband(proc.err, -1, NULL);
finish_command(&proc);
}
}
static void check_aliased_update(struct command *cmd, struct string_list *list)
{
struct strbuf buf = STRBUF_INIT;
const char *dst_name;
struct string_list_item *item;
struct command *dst_cmd;
unsigned char sha1[20];
char cmd_oldh[41], cmd_newh[41], dst_oldh[41], dst_newh[41];
int flag;
strbuf_addf(&buf, "%s%s", get_git_namespace(), cmd->ref_name);
dst_name = resolve_ref_unsafe(buf.buf, sha1, 0, &flag);
strbuf_release(&buf);
if (!(flag & REF_ISSYMREF))
return;
dst_name = strip_namespace(dst_name);
if (!dst_name) {
rp_error("refusing update to broken symref '%s'", cmd->ref_name);
cmd->skip_update = 1;
cmd->error_string = "broken symref";
return;
}
if ((item = string_list_lookup(list, dst_name)) == NULL)
return;
cmd->skip_update = 1;
dst_cmd = (struct command *) item->util;
if (!hashcmp(cmd->old_sha1, dst_cmd->old_sha1) &&
!hashcmp(cmd->new_sha1, dst_cmd->new_sha1))
return;
dst_cmd->skip_update = 1;
strcpy(cmd_oldh, find_unique_abbrev(cmd->old_sha1, DEFAULT_ABBREV));
strcpy(cmd_newh, find_unique_abbrev(cmd->new_sha1, DEFAULT_ABBREV));
strcpy(dst_oldh, find_unique_abbrev(dst_cmd->old_sha1, DEFAULT_ABBREV));
strcpy(dst_newh, find_unique_abbrev(dst_cmd->new_sha1, DEFAULT_ABBREV));
rp_error("refusing inconsistent update between symref '%s' (%s..%s) and"
" its target '%s' (%s..%s)",
cmd->ref_name, cmd_oldh, cmd_newh,
dst_cmd->ref_name, dst_oldh, dst_newh);
cmd->error_string = dst_cmd->error_string =
"inconsistent aliased update";
}
static void check_aliased_updates(struct command *commands)
{
struct command *cmd;
struct string_list ref_list = STRING_LIST_INIT_NODUP;
for (cmd = commands; cmd; cmd = cmd->next) {
struct string_list_item *item =
string_list_append(&ref_list, cmd->ref_name);
item->util = (void *)cmd;
}
sort_string_list(&ref_list);
for (cmd = commands; cmd; cmd = cmd->next) {
if (!cmd->error_string)
check_aliased_update(cmd, &ref_list);
}
string_list_clear(&ref_list, 0);
}
static int command_singleton_iterator(void *cb_data, unsigned char sha1[20])
{
struct command **cmd_list = cb_data;
struct command *cmd = *cmd_list;
if (!cmd || is_null_sha1(cmd->new_sha1))
return -1; /* end of list */
*cmd_list = NULL; /* this returns only one */
hashcpy(sha1, cmd->new_sha1);
return 0;
}
static void set_connectivity_errors(struct command *commands,
struct shallow_info *si)
{
struct command *cmd;
for (cmd = commands; cmd; cmd = cmd->next) {
struct command *singleton = cmd;
if (shallow_update && si->shallow_ref[cmd->index])
/* to be checked in update_shallow_ref() */
continue;
if (!check_everything_connected(command_singleton_iterator,
0, &singleton))
continue;
cmd->error_string = "missing necessary objects";
}
}
struct iterate_data {
struct command *cmds;
struct shallow_info *si;
};
static int iterate_receive_command_list(void *cb_data, unsigned char sha1[20])
{
struct iterate_data *data = cb_data;
struct command **cmd_list = &data->cmds;
struct command *cmd = *cmd_list;
for (; cmd; cmd = cmd->next) {
if (shallow_update && data->si->shallow_ref[cmd->index])
/* to be checked in update_shallow_ref() */
continue;
if (!is_null_sha1(cmd->new_sha1) && !cmd->skip_update) {
hashcpy(sha1, cmd->new_sha1);
*cmd_list = cmd->next;
return 0;
}
}
*cmd_list = NULL;
return -1; /* end of list */
}
static void reject_updates_to_hidden(struct command *commands)
{
struct command *cmd;
for (cmd = commands; cmd; cmd = cmd->next) {
if (cmd->error_string || !ref_is_hidden(cmd->ref_name))
continue;
if (is_null_sha1(cmd->new_sha1))
cmd->error_string = "deny deleting a hidden ref";
else
cmd->error_string = "deny updating a hidden ref";
}
}
static void execute_commands(struct command *commands,
const char *unpacker_error,
struct shallow_info *si)
{
int checked_connectivity;
struct command *cmd;
unsigned char sha1[20];
struct iterate_data data;
if (unpacker_error) {
for (cmd = commands; cmd; cmd = cmd->next)
cmd->error_string = "unpacker error";
return;
}
data.cmds = commands;
data.si = si;
if (check_everything_connected(iterate_receive_command_list, 0, &data))
set_connectivity_errors(commands, si);
reject_updates_to_hidden(commands);
if (run_receive_hook(commands, "pre-receive", 0)) {
for (cmd = commands; cmd; cmd = cmd->next) {
if (!cmd->error_string)
cmd->error_string = "pre-receive hook declined";
}
return;
}
check_aliased_updates(commands);
free(head_name_to_free);
head_name = head_name_to_free = resolve_refdup("HEAD", sha1, 0, NULL);
checked_connectivity = 1;
for (cmd = commands; cmd; cmd = cmd->next) {
if (cmd->error_string)
continue;
if (cmd->skip_update)
continue;
cmd->error_string = update(cmd, si);
if (shallow_update && !cmd->error_string &&
si->shallow_ref[cmd->index]) {
error("BUG: connectivity check has not been run on ref %s",
cmd->ref_name);
checked_connectivity = 0;
}
}
if (shallow_update && !checked_connectivity)
error("BUG: run 'git fsck' for safety.\n"
"If there are errors, try to remove "
"the reported refs above");
}
static struct command **queue_command(struct command **tail,
const char *line,
int linelen)
{
unsigned char old_sha1[20], new_sha1[20];
struct command *cmd;
const char *refname;
int reflen;
if (linelen < 83 ||
line[40] != ' ' ||
line[81] != ' ' ||
get_sha1_hex(line, old_sha1) ||
get_sha1_hex(line + 41, new_sha1))
die("protocol error: expected old/new/ref, got '%s'", line);
refname = line + 82;
reflen = linelen - 82;
cmd = xcalloc(1, sizeof(struct command) + reflen + 1);
hashcpy(cmd->old_sha1, old_sha1);
hashcpy(cmd->new_sha1, new_sha1);
memcpy(cmd->ref_name, refname, reflen);
cmd->ref_name[reflen] = '\0';
*tail = cmd;
return &cmd->next;
}
static struct command *read_head_info(struct sha1_array *shallow)
{
struct command *commands = NULL;
struct command **p = &commands;
for (;;) {
char *line;
int len, linelen;
line = packet_read_line(0, &len);
if (!line)
break;
if (len == 48 && starts_with(line, "shallow ")) {
unsigned char sha1[20];
if (get_sha1_hex(line + 8, sha1))
die("protocol error: expected shallow sha, got '%s'",
line + 8);
sha1_array_append(shallow, sha1);
continue;
}
linelen = strlen(line);
if (linelen < len) {
const char *feature_list = line + linelen + 1;
if (parse_feature_request(feature_list, "report-status"))
report_status = 1;
if (parse_feature_request(feature_list, "side-band-64k"))
use_sideband = LARGE_PACKET_MAX;
if (parse_feature_request(feature_list, "quiet"))
quiet = 1;
}
if (!strcmp(line, "push-cert")) {
int true_flush = 0;
char certbuf[1024];
for (;;) {
len = packet_read(0, NULL, NULL,
certbuf, sizeof(certbuf), 0);
if (!len) {
true_flush = 1;
break;
}
if (!strcmp(certbuf, "push-cert-end\n"))
break; /* end of cert */
strbuf_addstr(&push_cert, certbuf);
}
if (true_flush)
break;
continue;
}
p = queue_command(p, line, linelen);
}
return commands;
}
static const char *parse_pack_header(struct pack_header *hdr)
{
switch (read_pack_header(0, hdr)) {
case PH_ERROR_EOF:
return "eof before pack header was fully read";
case PH_ERROR_PACK_SIGNATURE:
return "protocol error (pack signature mismatch detected)";
case PH_ERROR_PROTOCOL:
return "protocol error (pack version unsupported)";
default:
return "unknown error in parse_pack_header";
case 0:
return NULL;
}
}
static const char *pack_lockfile;
static const char *unpack(int err_fd, struct shallow_info *si)
{
struct pack_header hdr;
struct argv_array av = ARGV_ARRAY_INIT;
const char *hdr_err;
int status;
char hdr_arg[38];
struct child_process child;
int fsck_objects = (receive_fsck_objects >= 0
? receive_fsck_objects
: transfer_fsck_objects >= 0
? transfer_fsck_objects
: 0);
hdr_err = parse_pack_header(&hdr);
if (hdr_err) {
if (err_fd > 0)
close(err_fd);
return hdr_err;
}
snprintf(hdr_arg, sizeof(hdr_arg),
"--pack_header=%"PRIu32",%"PRIu32,
ntohl(hdr.hdr_version), ntohl(hdr.hdr_entries));
if (si->nr_ours || si->nr_theirs) {
alt_shallow_file = setup_temporary_shallow(si->shallow);
argv_array_pushl(&av, "--shallow-file", alt_shallow_file, NULL);
}
memset(&child, 0, sizeof(child));
if (ntohl(hdr.hdr_entries) < unpack_limit) {
argv_array_pushl(&av, "unpack-objects", hdr_arg, NULL);
if (quiet)
argv_array_push(&av, "-q");
if (fsck_objects)
argv_array_push(&av, "--strict");
child.argv = av.argv;
child.no_stdout = 1;
child.err = err_fd;
child.git_cmd = 1;
status = run_command(&child);
if (status)
return "unpack-objects abnormal exit";
} else {
int s;
char keep_arg[256];
s = sprintf(keep_arg, "--keep=receive-pack %"PRIuMAX" on ", (uintmax_t) getpid());
if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
strcpy(keep_arg + s, "localhost");
argv_array_pushl(&av, "index-pack",
"--stdin", hdr_arg, keep_arg, NULL);
if (fsck_objects)
argv_array_push(&av, "--strict");
if (fix_thin)
argv_array_push(&av, "--fix-thin");
child.argv = av.argv;
child.out = -1;
child.err = err_fd;
child.git_cmd = 1;
status = start_command(&child);
if (status)
return "index-pack fork failed";
pack_lockfile = index_pack_lockfile(child.out);
close(child.out);
status = finish_command(&child);
if (status)
return "index-pack abnormal exit";
reprepare_packed_git();
}
return NULL;
}
static const char *unpack_with_sideband(struct shallow_info *si)
{
struct async muxer;
const char *ret;
if (!use_sideband)
return unpack(0, si);
memset(&muxer, 0, sizeof(muxer));
muxer.proc = copy_to_sideband;
muxer.in = -1;
if (start_async(&muxer))
return NULL;
ret = unpack(muxer.in, si);
finish_async(&muxer);
return ret;
}
static void prepare_shallow_update(struct command *commands,
struct shallow_info *si)
{
int i, j, k, bitmap_size = (si->ref->nr + 31) / 32;
si->used_shallow = xmalloc(sizeof(*si->used_shallow) *
si->shallow->nr);
assign_shallow_commits_to_refs(si, si->used_shallow, NULL);
si->need_reachability_test =
xcalloc(si->shallow->nr, sizeof(*si->need_reachability_test));
si->reachable =
xcalloc(si->shallow->nr, sizeof(*si->reachable));
si->shallow_ref = xcalloc(si->ref->nr, sizeof(*si->shallow_ref));
for (i = 0; i < si->nr_ours; i++)
si->need_reachability_test[si->ours[i]] = 1;
for (i = 0; i < si->shallow->nr; i++) {
if (!si->used_shallow[i])
continue;
for (j = 0; j < bitmap_size; j++) {
if (!si->used_shallow[i][j])
continue;
si->need_reachability_test[i]++;
for (k = 0; k < 32; k++)
if (si->used_shallow[i][j] & (1 << k))
si->shallow_ref[j * 32 + k]++;
}
/*
* true for those associated with some refs and belong
* in "ours" list aka "step 7 not done yet"
*/
si->need_reachability_test[i] =
si->need_reachability_test[i] > 1;
}
/*
* keep hooks happy by forcing a temporary shallow file via
* env variable because we can't add --shallow-file to every
* command. check_everything_connected() will be done with
* true .git/shallow though.
*/
setenv(GIT_SHALLOW_FILE_ENVIRONMENT, alt_shallow_file, 1);
}
static void update_shallow_info(struct command *commands,
struct shallow_info *si,
struct sha1_array *ref)
{
struct command *cmd;
int *ref_status;
remove_nonexistent_theirs_shallow(si);
if (!si->nr_ours && !si->nr_theirs) {
shallow_update = 0;
return;
}
for (cmd = commands; cmd; cmd = cmd->next) {
if (is_null_sha1(cmd->new_sha1))
continue;
sha1_array_append(ref, cmd->new_sha1);
cmd->index = ref->nr - 1;
}
si->ref = ref;
if (shallow_update) {
prepare_shallow_update(commands, si);
return;
}
ref_status = xmalloc(sizeof(*ref_status) * ref->nr);
assign_shallow_commits_to_refs(si, NULL, ref_status);
for (cmd = commands; cmd; cmd = cmd->next) {
if (is_null_sha1(cmd->new_sha1))
continue;
if (ref_status[cmd->index]) {
cmd->error_string = "shallow update not allowed";
cmd->skip_update = 1;
}
}
free(ref_status);
}
static void report(struct command *commands, const char *unpack_status)
{
struct command *cmd;
struct strbuf buf = STRBUF_INIT;
packet_buf_write(&buf, "unpack %s\n",
unpack_status ? unpack_status : "ok");
for (cmd = commands; cmd; cmd = cmd->next) {
if (!cmd->error_string)
packet_buf_write(&buf, "ok %s\n",
cmd->ref_name);
else
packet_buf_write(&buf, "ng %s %s\n",
cmd->ref_name, cmd->error_string);
}
packet_buf_flush(&buf);
if (use_sideband)
send_sideband(1, 1, buf.buf, buf.len, use_sideband);
else
write_or_die(1, buf.buf, buf.len);
strbuf_release(&buf);
}
static int delete_only(struct command *commands)
{
struct command *cmd;
for (cmd = commands; cmd; cmd = cmd->next) {
if (!is_null_sha1(cmd->new_sha1))
return 0;
}
return 1;
}
int cmd_receive_pack(int argc, const char **argv, const char *prefix)
{
int advertise_refs = 0;
int stateless_rpc = 0;
int i;
const char *dir = NULL;
struct command *commands;
struct sha1_array shallow = SHA1_ARRAY_INIT;
struct sha1_array ref = SHA1_ARRAY_INIT;
struct shallow_info si;
packet_trace_identity("receive-pack");
argv++;
for (i = 1; i < argc; i++) {
const char *arg = *argv++;
if (*arg == '-') {
if (!strcmp(arg, "--quiet")) {
quiet = 1;
continue;
}
if (!strcmp(arg, "--advertise-refs")) {
advertise_refs = 1;
continue;
}
if (!strcmp(arg, "--stateless-rpc")) {
stateless_rpc = 1;
continue;
}
if (!strcmp(arg, "--reject-thin-pack-for-testing")) {
fix_thin = 0;
continue;
}
usage(receive_pack_usage);
}
if (dir)
usage(receive_pack_usage);
dir = arg;
}
if (!dir)
usage(receive_pack_usage);
setup_path();
if (!enter_repo(dir, 0))
die("'%s' does not appear to be a git repository", dir);
git_config(receive_pack_config, NULL);
if (0 <= transfer_unpack_limit)
unpack_limit = transfer_unpack_limit;
else if (0 <= receive_unpack_limit)
unpack_limit = receive_unpack_limit;
if (advertise_refs || !stateless_rpc) {
write_head_info();
}
if (advertise_refs)
return 0;
if ((commands = read_head_info(&shallow)) != NULL) {
const char *unpack_status = NULL;
prepare_shallow_info(&si, &shallow);
if (!si.nr_ours && !si.nr_theirs)
shallow_update = 0;
if (!delete_only(commands)) {
unpack_status = unpack_with_sideband(&si);
update_shallow_info(commands, &si, &ref);
}
execute_commands(commands, unpack_status, &si);
if (pack_lockfile)
unlink_or_warn(pack_lockfile);
if (report_status)
report(commands, unpack_status);
run_receive_hook(commands, "post-receive", 1);
run_update_post_hook(commands);
if (auto_gc) {
const char *argv_gc_auto[] = {
"gc", "--auto", "--quiet", NULL,
};
int opt = RUN_GIT_CMD | RUN_COMMAND_STDOUT_TO_STDERR;
run_command_v_opt(argv_gc_auto, opt);
}
if (auto_update_server_info)
update_server_info(0);
clear_shallow_info(&si);
}
if (use_sideband)
packet_flush(1);
sha1_array_clear(&shallow);
sha1_array_clear(&ref);
return 0;
}
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