1
0
Fork 0
mirror of https://github.com/git/git.git synced 2024-10-29 21:37:53 +01:00
git/upload-pack.c
Jeff King 06f15bf1f3 upload-pack: make sure "want" objects are parsed
When upload-pack receives a "want" line from the client, it
adds it to an object array. We call lookup_object to find
the actual object, which will only check for objects already
in memory. This works because we are expecting to find
objects that we already loaded during the ref advertisement.

We use the resulting object structs for a variety of
purposes. Some of them care only about the object flags, but
others care about the type of the object (e.g.,
ok_to_give_up), or even feed them to the revision parser
(when --depth is used), which assumes that objects it
receives are fully parsed.

Once upon a time, this was OK; any object we loaded into
memory would also have been parsed. But since 435c833
(upload-pack: use peel_ref for ref advertisements,
2012-10-04), we try to avoid parsing objects during the ref
advertisement. This means that lookup_object may return an
object with a type of OBJ_NONE. The resulting mess depends
on the exact set of objects, but can include the revision
parser barfing, or the shallow code sending the wrong set of
objects.

This patch teaches upload-pack to parse each "want" object
as we receive it. We do not replace the lookup_object call
with parse_object, as the current code is careful not to let
just any object appear on a "want" line, but rather only one
we have previously advertised (whereas parse_object would
actually load any arbitrary object from disk).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-03-16 22:16:56 -07:00

836 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 "sigchain.h"
#include "version.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)
static unsigned long oldest_have;
static int multi_ack, nr_our_refs;
static int no_done;
static int use_thin_pack, use_ofs_delta, use_include_tag;
static int no_progress, daemon_mode;
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;
/* 0 for no sideband,
* otherwise maximum packet size (up to 65520 bytes).
*/
static int use_sideband;
static int debug_fd;
static int advertise_refs;
static int stateless_rpc;
static void reset_timeout(void)
{
alarm(timeout);
}
static int strip(char *line, int len)
{
if (len && line[len-1] == '\n')
line[--len] = 0;
return len;
}
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;
}
return safe_write(fd, data, sz);
}
static FILE *pack_pipe = NULL;
static void show_commit(struct commit *commit, void *data)
{
if (commit->object.flags & BOUNDARY)
fputc('-', pack_pipe);
if (fputs(sha1_to_hex(commit->object.sha1), pack_pipe) < 0)
die("broken output pipe");
fputc('\n', pack_pipe);
fflush(pack_pipe);
free(commit->buffer);
commit->buffer = NULL;
}
static void show_object(struct object *obj,
const struct name_path *path, const char *component,
void *cb_data)
{
show_object_with_name(pack_pipe, obj, path, component);
}
static void show_edge(struct commit *commit)
{
fprintf(pack_pipe, "-%s\n", sha1_to_hex(commit->object.sha1));
}
static int do_rev_list(int in, int out, void *user_data)
{
int i;
struct rev_info revs;
pack_pipe = xfdopen(out, "w");
init_revisions(&revs, NULL);
revs.tag_objects = 1;
revs.tree_objects = 1;
revs.blob_objects = 1;
if (use_thin_pack)
revs.edge_hint = 1;
for (i = 0; i < want_obj.nr; i++) {
struct object *o = want_obj.objects[i].item;
/* why??? */
o->flags &= ~UNINTERESTING;
add_pending_object(&revs, o, NULL);
}
for (i = 0; i < have_obj.nr; i++) {
struct object *o = have_obj.objects[i].item;
o->flags |= UNINTERESTING;
add_pending_object(&revs, o, NULL);
}
setup_revisions(0, NULL, &revs, NULL);
if (prepare_revision_walk(&revs))
die("revision walk setup failed");
mark_edges_uninteresting(revs.commits, &revs, show_edge);
if (use_thin_pack)
for (i = 0; i < extra_edge_obj.nr; i++)
fprintf(pack_pipe, "-%s\n", sha1_to_hex(
extra_edge_obj.objects[i].item->sha1));
traverse_commit_list(&revs, show_commit, show_object, NULL);
fflush(pack_pipe);
fclose(pack_pipe);
return 0;
}
static void create_pack_file(void)
{
struct async rev_list;
struct child_process pack_objects;
int create_full_pack = (nr_our_refs == want_obj.nr && !have_obj.nr);
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[10];
int arg = 0;
argv[arg++] = "pack-objects";
if (!shallow_nr) {
argv[arg++] = "--revs";
if (create_full_pack)
argv[arg++] = "--all";
else 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");
if (shallow_nr) {
memset(&rev_list, 0, sizeof(rev_list));
rev_list.proc = do_rev_list;
rev_list.out = pack_objects.in;
if (start_async(&rev_list))
die("git upload-pack: unable to fork git-rev-list");
}
else {
FILE *pipe_fd = xfdopen(pack_objects.in, "w");
if (!create_full_pack) {
int i;
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));
}
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;
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;
if (poll(pfd, pollsize, -1) < 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;
}
}
if (finish_command(&pack_objects)) {
error("git upload-pack: git-pack-objects died with error.");
goto fail;
}
if (shallow_nr && finish_async(&rev_list))
goto fail; /* error was already reported */
/* 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)
{
static char line[1000];
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 (;;) {
int len = packet_read_line(0, line, sizeof(line));
reset_timeout();
if (!len) {
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;
}
strip(line, len);
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 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 (!(o->flags & OUR_REF))
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 (o->flags & OUR_REF)
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 (!(o->flags & OUR_REF))
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;
static char line[1000];
int len, depth = 0;
int has_non_tip = 0;
shallow_nr = 0;
if (debug_fd)
write_str_in_full(debug_fd, "#S\n");
for (;;) {
struct object *o;
const char *features;
unsigned char sha1_buf[20];
len = packet_read_line(0, line, sizeof(line));
reset_timeout();
if (!len)
break;
if (debug_fd)
write_in_full(debug_fd, line, len);
if (!prefixcmp(line, "shallow ")) {
unsigned char sha1[20];
struct object *object;
if (get_sha1(line + 8, sha1))
die("invalid shallow line: %s", line);
object = parse_object(sha1);
if (!object)
die("did not find object for %s", line);
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 = lookup_object(sha1_buf);
if (!o || !parse_object(o->sha1))
die("git upload-pack: not our ref %s",
sha1_to_hex(sha1_buf));
if (!(o->flags & WANTED)) {
o->flags |= WANTED;
if (!(o->flags & OUR_REF))
has_non_tip = 1;
add_object_array(o, NULL, &want_obj);
}
}
if (debug_fd)
write_str_in_full(debug_fd, "#E\n");
/*
* 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, *backup;
int i;
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);
}
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";
struct object *o = lookup_unknown_object(sha1);
const char *refname_nons = strip_namespace(refname);
unsigned char peeled[20];
if (capabilities)
packet_write(1, "%s %s%c%s%s agent=%s\n",
sha1_to_hex(sha1), refname_nons,
0, capabilities,
stateless_rpc ? " no-done" : "",
git_user_agent_sanitized());
else
packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname_nons);
capabilities = NULL;
if (!(o->flags & OUR_REF)) {
o->flags |= OUR_REF;
nr_our_refs++;
}
if (!peel_ref(refname, peeled))
packet_write(1, "%s %s^{}\n", sha1_to_hex(peeled), refname_nons);
return 0;
}
static int mark_our_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
{
struct object *o = parse_object(sha1);
if (!o)
die("git upload-pack: cannot find object %s:", sha1_to_hex(sha1));
if (!(o->flags & OUR_REF)) {
o->flags |= OUR_REF;
nr_our_refs++;
}
return 0;
}
static void upload_pack(void)
{
if (advertise_refs || !stateless_rpc) {
reset_timeout();
head_ref_namespaced(send_ref, NULL);
for_each_namespaced_ref(send_ref, NULL);
packet_flush(1);
} else {
head_ref_namespaced(mark_our_ref, NULL);
for_each_namespaced_ref(mark_our_ref, NULL);
}
if (advertise_refs)
return;
receive_needs();
if (want_obj.nr) {
get_common_commits();
create_pack_file();
}
}
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");
if (getenv("GIT_DEBUG_SEND_PACK"))
debug_fd = atoi(getenv("GIT_DEBUG_SEND_PACK"));
upload_pack();
return 0;
}