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git/upload-pack.c
Junio C Hamano 9196a2f8bd Merge branch 'jc/upload-pack-send-symref' into maint
One long-standing flaw in the pack transfer protocol used by "git
clone" was that there was no way to tell the other end which branch
"HEAD" points at, and the receiving end needed to guess.  A new
capability has been defined in the pack protocol to convey this
information so that cloning from a repository with more than one
branches pointing at the same commit where the HEAD is at now
reliably sets the initial branch in the resulting repository.

* jc/upload-pack-send-symref:
  t5570: Update for clone-progress-to-stderr branch
  t5570: Update for symref capability
  clone: test the new HEAD detection logic
  connect: annotate refs with their symref information in get_remote_head()
  connect.c: make parse_feature_value() static
  upload-pack: send non-HEAD symbolic refs
  upload-pack: send symbolic ref information as capability
  upload-pack.c: do not pass confusing cb_data to mark_our_ref()
  t5505: fix "set-head --auto with ambiguous HEAD" test
2013-11-08 11:38:00 -08:00

844 lines
20 KiB
C

#include "cache.h"
#include "refs.h"
#include "pkt-line.h"
#include "sideband.h"
#include "tag.h"
#include "object.h"
#include "commit.h"
#include "exec_cmd.h"
#include "diff.h"
#include "revision.h"
#include "list-objects.h"
#include "run-command.h"
#include "connect.h"
#include "sigchain.h"
#include "version.h"
#include "string-list.h"
static const char upload_pack_usage[] = "git upload-pack [--strict] [--timeout=<n>] <dir>";
/* bits #0..7 in revision.h, #8..10 in commit.c */
#define THEY_HAVE (1u << 11)
#define OUR_REF (1u << 12)
#define WANTED (1u << 13)
#define COMMON_KNOWN (1u << 14)
#define REACHABLE (1u << 15)
#define SHALLOW (1u << 16)
#define NOT_SHALLOW (1u << 17)
#define CLIENT_SHALLOW (1u << 18)
#define HIDDEN_REF (1u << 19)
static unsigned long oldest_have;
static int multi_ack;
static int no_done;
static int use_thin_pack, use_ofs_delta, use_include_tag;
static int no_progress, daemon_mode;
static int allow_tip_sha1_in_want;
static int shallow_nr;
static struct object_array have_obj;
static struct object_array want_obj;
static struct object_array extra_edge_obj;
static unsigned int timeout;
static int keepalive = 5;
/* 0 for no sideband,
* otherwise maximum packet size (up to 65520 bytes).
*/
static int use_sideband;
static int advertise_refs;
static int stateless_rpc;
static void reset_timeout(void)
{
alarm(timeout);
}
static ssize_t send_client_data(int fd, const char *data, ssize_t sz)
{
if (use_sideband)
return send_sideband(1, fd, data, sz, use_sideband);
if (fd == 3)
/* emergency quit */
fd = 2;
if (fd == 2) {
/* XXX: are we happy to lose stuff here? */
xwrite(fd, data, sz);
return sz;
}
write_or_die(fd, data, sz);
return sz;
}
static void create_pack_file(void)
{
struct child_process pack_objects;
char data[8193], progress[128];
char abort_msg[] = "aborting due to possible repository "
"corruption on the remote side.";
int buffered = -1;
ssize_t sz;
const char *argv[12];
int i, arg = 0;
FILE *pipe_fd;
char *shallow_file = NULL;
if (shallow_nr) {
shallow_file = setup_temporary_shallow();
argv[arg++] = "--shallow-file";
argv[arg++] = shallow_file;
}
argv[arg++] = "pack-objects";
argv[arg++] = "--revs";
if (use_thin_pack)
argv[arg++] = "--thin";
argv[arg++] = "--stdout";
if (!no_progress)
argv[arg++] = "--progress";
if (use_ofs_delta)
argv[arg++] = "--delta-base-offset";
if (use_include_tag)
argv[arg++] = "--include-tag";
argv[arg++] = NULL;
memset(&pack_objects, 0, sizeof(pack_objects));
pack_objects.in = -1;
pack_objects.out = -1;
pack_objects.err = -1;
pack_objects.git_cmd = 1;
pack_objects.argv = argv;
if (start_command(&pack_objects))
die("git upload-pack: unable to fork git-pack-objects");
pipe_fd = xfdopen(pack_objects.in, "w");
for (i = 0; i < want_obj.nr; i++)
fprintf(pipe_fd, "%s\n",
sha1_to_hex(want_obj.objects[i].item->sha1));
fprintf(pipe_fd, "--not\n");
for (i = 0; i < have_obj.nr; i++)
fprintf(pipe_fd, "%s\n",
sha1_to_hex(have_obj.objects[i].item->sha1));
for (i = 0; i < extra_edge_obj.nr; i++)
fprintf(pipe_fd, "%s\n",
sha1_to_hex(extra_edge_obj.objects[i].item->sha1));
fprintf(pipe_fd, "\n");
fflush(pipe_fd);
fclose(pipe_fd);
/* We read from pack_objects.err to capture stderr output for
* progress bar, and pack_objects.out to capture the pack data.
*/
while (1) {
struct pollfd pfd[2];
int pe, pu, pollsize;
int ret;
reset_timeout();
pollsize = 0;
pe = pu = -1;
if (0 <= pack_objects.out) {
pfd[pollsize].fd = pack_objects.out;
pfd[pollsize].events = POLLIN;
pu = pollsize;
pollsize++;
}
if (0 <= pack_objects.err) {
pfd[pollsize].fd = pack_objects.err;
pfd[pollsize].events = POLLIN;
pe = pollsize;
pollsize++;
}
if (!pollsize)
break;
ret = poll(pfd, pollsize, 1000 * keepalive);
if (ret < 0) {
if (errno != EINTR) {
error("poll failed, resuming: %s",
strerror(errno));
sleep(1);
}
continue;
}
if (0 <= pe && (pfd[pe].revents & (POLLIN|POLLHUP))) {
/* Status ready; we ship that in the side-band
* or dump to the standard error.
*/
sz = xread(pack_objects.err, progress,
sizeof(progress));
if (0 < sz)
send_client_data(2, progress, sz);
else if (sz == 0) {
close(pack_objects.err);
pack_objects.err = -1;
}
else
goto fail;
/* give priority to status messages */
continue;
}
if (0 <= pu && (pfd[pu].revents & (POLLIN|POLLHUP))) {
/* Data ready; we keep the last byte to ourselves
* in case we detect broken rev-list, so that we
* can leave the stream corrupted. This is
* unfortunate -- unpack-objects would happily
* accept a valid packdata with trailing garbage,
* so appending garbage after we pass all the
* pack data is not good enough to signal
* breakage to downstream.
*/
char *cp = data;
ssize_t outsz = 0;
if (0 <= buffered) {
*cp++ = buffered;
outsz++;
}
sz = xread(pack_objects.out, cp,
sizeof(data) - outsz);
if (0 < sz)
;
else if (sz == 0) {
close(pack_objects.out);
pack_objects.out = -1;
}
else
goto fail;
sz += outsz;
if (1 < sz) {
buffered = data[sz-1] & 0xFF;
sz--;
}
else
buffered = -1;
sz = send_client_data(1, data, sz);
if (sz < 0)
goto fail;
}
/*
* We hit the keepalive timeout without saying anything; send
* an empty message on the data sideband just to let the other
* side know we're still working on it, but don't have any data
* yet.
*
* If we don't have a sideband channel, there's no room in the
* protocol to say anything, so those clients are just out of
* luck.
*/
if (!ret && use_sideband) {
static const char buf[] = "0005\1";
write_or_die(1, buf, 5);
}
}
if (finish_command(&pack_objects)) {
error("git upload-pack: git-pack-objects died with error.");
goto fail;
}
if (shallow_file) {
if (*shallow_file)
unlink(shallow_file);
free(shallow_file);
}
/* flush the data */
if (0 <= buffered) {
data[0] = buffered;
sz = send_client_data(1, data, 1);
if (sz < 0)
goto fail;
fprintf(stderr, "flushed.\n");
}
if (use_sideband)
packet_flush(1);
return;
fail:
send_client_data(3, abort_msg, sizeof(abort_msg));
die("git upload-pack: %s", abort_msg);
}
static int got_sha1(char *hex, unsigned char *sha1)
{
struct object *o;
int we_knew_they_have = 0;
if (get_sha1_hex(hex, sha1))
die("git upload-pack: expected SHA1 object, got '%s'", hex);
if (!has_sha1_file(sha1))
return -1;
o = parse_object(sha1);
if (!o)
die("oops (%s)", sha1_to_hex(sha1));
if (o->type == OBJ_COMMIT) {
struct commit_list *parents;
struct commit *commit = (struct commit *)o;
if (o->flags & THEY_HAVE)
we_knew_they_have = 1;
else
o->flags |= THEY_HAVE;
if (!oldest_have || (commit->date < oldest_have))
oldest_have = commit->date;
for (parents = commit->parents;
parents;
parents = parents->next)
parents->item->object.flags |= THEY_HAVE;
}
if (!we_knew_they_have) {
add_object_array(o, NULL, &have_obj);
return 1;
}
return 0;
}
static int reachable(struct commit *want)
{
struct commit_list *work = NULL;
commit_list_insert_by_date(want, &work);
while (work) {
struct commit_list *list = work->next;
struct commit *commit = work->item;
free(work);
work = list;
if (commit->object.flags & THEY_HAVE) {
want->object.flags |= COMMON_KNOWN;
break;
}
if (!commit->object.parsed)
parse_object(commit->object.sha1);
if (commit->object.flags & REACHABLE)
continue;
commit->object.flags |= REACHABLE;
if (commit->date < oldest_have)
continue;
for (list = commit->parents; list; list = list->next) {
struct commit *parent = list->item;
if (!(parent->object.flags & REACHABLE))
commit_list_insert_by_date(parent, &work);
}
}
want->object.flags |= REACHABLE;
clear_commit_marks(want, REACHABLE);
free_commit_list(work);
return (want->object.flags & COMMON_KNOWN);
}
static int ok_to_give_up(void)
{
int i;
if (!have_obj.nr)
return 0;
for (i = 0; i < want_obj.nr; i++) {
struct object *want = want_obj.objects[i].item;
if (want->flags & COMMON_KNOWN)
continue;
want = deref_tag(want, "a want line", 0);
if (!want || want->type != OBJ_COMMIT) {
/* no way to tell if this is reachable by
* looking at the ancestry chain alone, so
* leave a note to ourselves not to worry about
* this object anymore.
*/
want_obj.objects[i].item->flags |= COMMON_KNOWN;
continue;
}
if (!reachable((struct commit *)want))
return 0;
}
return 1;
}
static int get_common_commits(void)
{
unsigned char sha1[20];
char last_hex[41];
int got_common = 0;
int got_other = 0;
int sent_ready = 0;
save_commit_buffer = 0;
for (;;) {
char *line = packet_read_line(0, NULL);
reset_timeout();
if (!line) {
if (multi_ack == 2 && got_common
&& !got_other && ok_to_give_up()) {
sent_ready = 1;
packet_write(1, "ACK %s ready\n", last_hex);
}
if (have_obj.nr == 0 || multi_ack)
packet_write(1, "NAK\n");
if (no_done && sent_ready) {
packet_write(1, "ACK %s\n", last_hex);
return 0;
}
if (stateless_rpc)
exit(0);
got_common = 0;
got_other = 0;
continue;
}
if (!prefixcmp(line, "have ")) {
switch (got_sha1(line+5, sha1)) {
case -1: /* they have what we do not */
got_other = 1;
if (multi_ack && ok_to_give_up()) {
const char *hex = sha1_to_hex(sha1);
if (multi_ack == 2) {
sent_ready = 1;
packet_write(1, "ACK %s ready\n", hex);
} else
packet_write(1, "ACK %s continue\n", hex);
}
break;
default:
got_common = 1;
memcpy(last_hex, sha1_to_hex(sha1), 41);
if (multi_ack == 2)
packet_write(1, "ACK %s common\n", last_hex);
else if (multi_ack)
packet_write(1, "ACK %s continue\n", last_hex);
else if (have_obj.nr == 1)
packet_write(1, "ACK %s\n", last_hex);
break;
}
continue;
}
if (!strcmp(line, "done")) {
if (have_obj.nr > 0) {
if (multi_ack)
packet_write(1, "ACK %s\n", last_hex);
return 0;
}
packet_write(1, "NAK\n");
return -1;
}
die("git upload-pack: expected SHA1 list, got '%s'", line);
}
}
static int is_our_ref(struct object *o)
{
return o->flags &
((allow_tip_sha1_in_want ? HIDDEN_REF : 0) | OUR_REF);
}
static void check_non_tip(void)
{
static const char *argv[] = {
"rev-list", "--stdin", NULL,
};
static struct child_process cmd;
struct object *o;
char namebuf[42]; /* ^ + SHA-1 + LF */
int i;
/* In the normal in-process case non-tip request can never happen */
if (!stateless_rpc)
goto error;
cmd.argv = argv;
cmd.git_cmd = 1;
cmd.no_stderr = 1;
cmd.in = -1;
cmd.out = -1;
if (start_command(&cmd))
goto error;
/*
* If rev-list --stdin encounters an unknown commit, it
* terminates, which will cause SIGPIPE in the write loop
* below.
*/
sigchain_push(SIGPIPE, SIG_IGN);
namebuf[0] = '^';
namebuf[41] = '\n';
for (i = get_max_object_index(); 0 < i; ) {
o = get_indexed_object(--i);
if (!o)
continue;
if (!is_our_ref(o))
continue;
memcpy(namebuf + 1, sha1_to_hex(o->sha1), 40);
if (write_in_full(cmd.in, namebuf, 42) < 0)
goto error;
}
namebuf[40] = '\n';
for (i = 0; i < want_obj.nr; i++) {
o = want_obj.objects[i].item;
if (is_our_ref(o))
continue;
memcpy(namebuf, sha1_to_hex(o->sha1), 40);
if (write_in_full(cmd.in, namebuf, 41) < 0)
goto error;
}
close(cmd.in);
sigchain_pop(SIGPIPE);
/*
* The commits out of the rev-list are not ancestors of
* our ref.
*/
i = read_in_full(cmd.out, namebuf, 1);
if (i)
goto error;
close(cmd.out);
/*
* rev-list may have died by encountering a bad commit
* in the history, in which case we do want to bail out
* even when it showed no commit.
*/
if (finish_command(&cmd))
goto error;
/* All the non-tip ones are ancestors of what we advertised */
return;
error:
/* Pick one of them (we know there at least is one) */
for (i = 0; i < want_obj.nr; i++) {
o = want_obj.objects[i].item;
if (!is_our_ref(o))
die("git upload-pack: not our ref %s",
sha1_to_hex(o->sha1));
}
}
static void receive_needs(void)
{
struct object_array shallows = OBJECT_ARRAY_INIT;
int depth = 0;
int has_non_tip = 0;
shallow_nr = 0;
for (;;) {
struct object *o;
const char *features;
unsigned char sha1_buf[20];
char *line = packet_read_line(0, NULL);
reset_timeout();
if (!line)
break;
if (!prefixcmp(line, "shallow ")) {
unsigned char sha1[20];
struct object *object;
if (get_sha1_hex(line + 8, sha1))
die("invalid shallow line: %s", line);
object = parse_object(sha1);
if (!object)
continue;
if (object->type != OBJ_COMMIT)
die("invalid shallow object %s", sha1_to_hex(sha1));
if (!(object->flags & CLIENT_SHALLOW)) {
object->flags |= CLIENT_SHALLOW;
add_object_array(object, NULL, &shallows);
}
continue;
}
if (!prefixcmp(line, "deepen ")) {
char *end;
depth = strtol(line + 7, &end, 0);
if (end == line + 7 || depth <= 0)
die("Invalid deepen: %s", line);
continue;
}
if (prefixcmp(line, "want ") ||
get_sha1_hex(line+5, sha1_buf))
die("git upload-pack: protocol error, "
"expected to get sha, not '%s'", line);
features = line + 45;
if (parse_feature_request(features, "multi_ack_detailed"))
multi_ack = 2;
else if (parse_feature_request(features, "multi_ack"))
multi_ack = 1;
if (parse_feature_request(features, "no-done"))
no_done = 1;
if (parse_feature_request(features, "thin-pack"))
use_thin_pack = 1;
if (parse_feature_request(features, "ofs-delta"))
use_ofs_delta = 1;
if (parse_feature_request(features, "side-band-64k"))
use_sideband = LARGE_PACKET_MAX;
else if (parse_feature_request(features, "side-band"))
use_sideband = DEFAULT_PACKET_MAX;
if (parse_feature_request(features, "no-progress"))
no_progress = 1;
if (parse_feature_request(features, "include-tag"))
use_include_tag = 1;
o = parse_object(sha1_buf);
if (!o)
die("git upload-pack: not our ref %s",
sha1_to_hex(sha1_buf));
if (!(o->flags & WANTED)) {
o->flags |= WANTED;
if (!is_our_ref(o))
has_non_tip = 1;
add_object_array(o, NULL, &want_obj);
}
}
/*
* We have sent all our refs already, and the other end
* should have chosen out of them. When we are operating
* in the stateless RPC mode, however, their choice may
* have been based on the set of older refs advertised
* by another process that handled the initial request.
*/
if (has_non_tip)
check_non_tip();
if (!use_sideband && daemon_mode)
no_progress = 1;
if (depth == 0 && shallows.nr == 0)
return;
if (depth > 0) {
struct commit_list *result = NULL, *backup = NULL;
int i;
if (depth == INFINITE_DEPTH)
for (i = 0; i < shallows.nr; i++) {
struct object *object = shallows.objects[i].item;
object->flags |= NOT_SHALLOW;
}
else
backup = result =
get_shallow_commits(&want_obj, depth,
SHALLOW, NOT_SHALLOW);
while (result) {
struct object *object = &result->item->object;
if (!(object->flags & (CLIENT_SHALLOW|NOT_SHALLOW))) {
packet_write(1, "shallow %s",
sha1_to_hex(object->sha1));
register_shallow(object->sha1);
shallow_nr++;
}
result = result->next;
}
free_commit_list(backup);
for (i = 0; i < shallows.nr; i++) {
struct object *object = shallows.objects[i].item;
if (object->flags & NOT_SHALLOW) {
struct commit_list *parents;
packet_write(1, "unshallow %s",
sha1_to_hex(object->sha1));
object->flags &= ~CLIENT_SHALLOW;
/* make sure the real parents are parsed */
unregister_shallow(object->sha1);
object->parsed = 0;
if (parse_commit((struct commit *)object))
die("invalid commit");
parents = ((struct commit *)object)->parents;
while (parents) {
add_object_array(&parents->item->object,
NULL, &want_obj);
parents = parents->next;
}
add_object_array(object, NULL, &extra_edge_obj);
}
/* make sure commit traversal conforms to client */
register_shallow(object->sha1);
}
packet_flush(1);
} else
if (shallows.nr > 0) {
int i;
for (i = 0; i < shallows.nr; i++)
register_shallow(shallows.objects[i].item->sha1);
}
shallow_nr += shallows.nr;
free(shallows.objects);
}
/* return non-zero if the ref is hidden, otherwise 0 */
static int mark_our_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
{
struct object *o = lookup_unknown_object(sha1);
if (ref_is_hidden(refname)) {
o->flags |= HIDDEN_REF;
return 1;
}
if (!o)
die("git upload-pack: cannot find object %s:", sha1_to_hex(sha1));
o->flags |= OUR_REF;
return 0;
}
static void format_symref_info(struct strbuf *buf, struct string_list *symref)
{
struct string_list_item *item;
if (!symref->nr)
return;
for_each_string_list_item(item, symref)
strbuf_addf(buf, " symref=%s:%s", item->string, (char *)item->util);
}
static int send_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
{
static const char *capabilities = "multi_ack thin-pack side-band"
" side-band-64k ofs-delta shallow no-progress"
" include-tag multi_ack_detailed";
const char *refname_nons = strip_namespace(refname);
unsigned char peeled[20];
if (mark_our_ref(refname, sha1, flag, NULL))
return 0;
if (capabilities) {
struct strbuf symref_info = STRBUF_INIT;
format_symref_info(&symref_info, cb_data);
packet_write(1, "%s %s%c%s%s%s%s agent=%s\n",
sha1_to_hex(sha1), refname_nons,
0, capabilities,
allow_tip_sha1_in_want ? " allow-tip-sha1-in-want" : "",
stateless_rpc ? " no-done" : "",
symref_info.buf,
git_user_agent_sanitized());
strbuf_release(&symref_info);
} else {
packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname_nons);
}
capabilities = NULL;
if (!peel_ref(refname, peeled))
packet_write(1, "%s %s^{}\n", sha1_to_hex(peeled), refname_nons);
return 0;
}
static int find_symref(const char *refname, const unsigned char *sha1, int flag,
void *cb_data)
{
const char *symref_target;
struct string_list_item *item;
unsigned char unused[20];
if ((flag & REF_ISSYMREF) == 0)
return 0;
symref_target = resolve_ref_unsafe(refname, unused, 0, &flag);
if (!symref_target || (flag & REF_ISSYMREF) == 0)
die("'%s' is a symref but it is not?", refname);
item = string_list_append(cb_data, refname);
item->util = xstrdup(symref_target);
return 0;
}
static void upload_pack(void)
{
struct string_list symref = STRING_LIST_INIT_DUP;
head_ref_namespaced(find_symref, &symref);
for_each_namespaced_ref(find_symref, &symref);
if (advertise_refs || !stateless_rpc) {
reset_timeout();
head_ref_namespaced(send_ref, &symref);
for_each_namespaced_ref(send_ref, &symref);
packet_flush(1);
} else {
head_ref_namespaced(mark_our_ref, NULL);
for_each_namespaced_ref(mark_our_ref, NULL);
}
string_list_clear(&symref, 1);
if (advertise_refs)
return;
receive_needs();
if (want_obj.nr) {
get_common_commits();
create_pack_file();
}
}
static int upload_pack_config(const char *var, const char *value, void *unused)
{
if (!strcmp("uploadpack.allowtipsha1inwant", var))
allow_tip_sha1_in_want = git_config_bool(var, value);
else if (!strcmp("uploadpack.keepalive", var)) {
keepalive = git_config_int(var, value);
if (!keepalive)
keepalive = -1;
}
return parse_hide_refs_config(var, value, "uploadpack");
}
int main(int argc, char **argv)
{
char *dir;
int i;
int strict = 0;
git_setup_gettext();
packet_trace_identity("upload-pack");
git_extract_argv0_path(argv[0]);
read_replace_refs = 0;
for (i = 1; i < argc; i++) {
char *arg = argv[i];
if (arg[0] != '-')
break;
if (!strcmp(arg, "--advertise-refs")) {
advertise_refs = 1;
continue;
}
if (!strcmp(arg, "--stateless-rpc")) {
stateless_rpc = 1;
continue;
}
if (!strcmp(arg, "--strict")) {
strict = 1;
continue;
}
if (!prefixcmp(arg, "--timeout=")) {
timeout = atoi(arg+10);
daemon_mode = 1;
continue;
}
if (!strcmp(arg, "--")) {
i++;
break;
}
}
if (i != argc-1)
usage(upload_pack_usage);
setup_path();
dir = argv[i];
if (!enter_repo(dir, strict))
die("'%s' does not appear to be a git repository", dir);
if (is_repository_shallow())
die("attempt to fetch/clone from a shallow repository");
git_config(upload_pack_config, NULL);
upload_pack();
return 0;
}