git/builtin/fetch-pack.c
Masaya Suzuki 2d103c31c2 pack-protocol.txt: accept error packets in any context
In the Git pack protocol definition, an error packet may appear only in
a certain context. However, servers can face a runtime error (e.g. I/O
error) at an arbitrary timing. This patch changes the protocol to allow
an error packet to be sent instead of any packet.

Without this protocol spec change, when a server cannot process a
request, there's no way to tell that to a client. Since the server
cannot produce a valid response, it would be forced to cut a connection
without telling why. With this protocol spec change, the server can be
more gentle in this situation. An old client may see these error packets
as an unexpected packet, but this is not worse than having an unexpected
EOF.

Following this protocol spec change, the error packet handling code is
moved to pkt-line.c. Implementation wise, this implementation uses
pkt-line to communicate with a subprocess. Since this is not a part of
Git protocol, it's possible that a packet that is not supposed to be an
error packet is mistakenly parsed as an error packet. This error packet
handling is enabled only for the Git pack protocol parsing code
considering this.

Signed-off-by: Masaya Suzuki <masayasuzuki@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-02 13:05:30 -08:00

268 lines
6.2 KiB
C

#include "builtin.h"
#include "pkt-line.h"
#include "fetch-pack.h"
#include "remote.h"
#include "connect.h"
#include "sha1-array.h"
#include "protocol.h"
static const char fetch_pack_usage[] =
"git fetch-pack [--all] [--stdin] [--quiet | -q] [--keep | -k] [--thin] "
"[--include-tag] [--upload-pack=<git-upload-pack>] [--depth=<n>] "
"[--no-progress] [--diag-url] [-v] [<host>:]<directory> [<refs>...]";
static void add_sought_entry(struct ref ***sought, int *nr, int *alloc,
const char *name)
{
struct ref *ref;
struct object_id oid;
const char *p;
if (!parse_oid_hex(name, &oid, &p)) {
if (*p == ' ') {
/* <oid> <ref>, find refname */
name = p + 1;
} else if (*p == '\0') {
; /* <oid>, leave oid as name */
} else {
/* <ref>, clear cruft from oid */
oidclr(&oid);
}
} else {
/* <ref>, clear cruft from get_oid_hex */
oidclr(&oid);
}
ref = alloc_ref(name);
oidcpy(&ref->old_oid, &oid);
(*nr)++;
ALLOC_GROW(*sought, *nr, *alloc);
(*sought)[*nr - 1] = ref;
}
int cmd_fetch_pack(int argc, const char **argv, const char *prefix)
{
int i, ret;
struct ref *ref = NULL;
const char *dest = NULL;
struct ref **sought = NULL;
int nr_sought = 0, alloc_sought = 0;
int fd[2];
char *pack_lockfile = NULL;
char **pack_lockfile_ptr = NULL;
struct child_process *conn;
struct fetch_pack_args args;
struct oid_array shallow = OID_ARRAY_INIT;
struct string_list deepen_not = STRING_LIST_INIT_DUP;
struct packet_reader reader;
fetch_if_missing = 0;
packet_trace_identity("fetch-pack");
memset(&args, 0, sizeof(args));
args.uploadpack = "git-upload-pack";
for (i = 1; i < argc && *argv[i] == '-'; i++) {
const char *arg = argv[i];
if (skip_prefix(arg, "--upload-pack=", &arg)) {
args.uploadpack = arg;
continue;
}
if (skip_prefix(arg, "--exec=", &arg)) {
args.uploadpack = arg;
continue;
}
if (!strcmp("--quiet", arg) || !strcmp("-q", arg)) {
args.quiet = 1;
continue;
}
if (!strcmp("--keep", arg) || !strcmp("-k", arg)) {
args.lock_pack = args.keep_pack;
args.keep_pack = 1;
continue;
}
if (!strcmp("--thin", arg)) {
args.use_thin_pack = 1;
continue;
}
if (!strcmp("--include-tag", arg)) {
args.include_tag = 1;
continue;
}
if (!strcmp("--all", arg)) {
args.fetch_all = 1;
continue;
}
if (!strcmp("--stdin", arg)) {
args.stdin_refs = 1;
continue;
}
if (!strcmp("--diag-url", arg)) {
args.diag_url = 1;
continue;
}
if (!strcmp("-v", arg)) {
args.verbose = 1;
continue;
}
if (skip_prefix(arg, "--depth=", &arg)) {
args.depth = strtol(arg, NULL, 0);
continue;
}
if (skip_prefix(arg, "--shallow-since=", &arg)) {
args.deepen_since = xstrdup(arg);
continue;
}
if (skip_prefix(arg, "--shallow-exclude=", &arg)) {
string_list_append(&deepen_not, arg);
continue;
}
if (!strcmp(arg, "--deepen-relative")) {
args.deepen_relative = 1;
continue;
}
if (!strcmp("--no-progress", arg)) {
args.no_progress = 1;
continue;
}
if (!strcmp("--stateless-rpc", arg)) {
args.stateless_rpc = 1;
continue;
}
if (!strcmp("--lock-pack", arg)) {
args.lock_pack = 1;
pack_lockfile_ptr = &pack_lockfile;
continue;
}
if (!strcmp("--check-self-contained-and-connected", arg)) {
args.check_self_contained_and_connected = 1;
continue;
}
if (!strcmp("--cloning", arg)) {
args.cloning = 1;
continue;
}
if (!strcmp("--update-shallow", arg)) {
args.update_shallow = 1;
continue;
}
if (!strcmp("--from-promisor", arg)) {
args.from_promisor = 1;
continue;
}
if (!strcmp("--no-dependents", arg)) {
args.no_dependents = 1;
continue;
}
if (skip_prefix(arg, ("--" CL_ARG__FILTER "="), &arg)) {
parse_list_objects_filter(&args.filter_options, arg);
continue;
}
if (!strcmp(arg, ("--no-" CL_ARG__FILTER))) {
list_objects_filter_set_no_filter(&args.filter_options);
continue;
}
usage(fetch_pack_usage);
}
if (deepen_not.nr)
args.deepen_not = &deepen_not;
if (i < argc)
dest = argv[i++];
else
usage(fetch_pack_usage);
/*
* Copy refs from cmdline to growable list, then append any
* refs from the standard input:
*/
for (; i < argc; i++)
add_sought_entry(&sought, &nr_sought, &alloc_sought, argv[i]);
if (args.stdin_refs) {
if (args.stateless_rpc) {
/* in stateless RPC mode we use pkt-line to read
* from stdin, until we get a flush packet
*/
for (;;) {
char *line = packet_read_line(0, NULL);
if (!line)
break;
add_sought_entry(&sought, &nr_sought, &alloc_sought, line);
}
}
else {
/* read from stdin one ref per line, until EOF */
struct strbuf line = STRBUF_INIT;
while (strbuf_getline_lf(&line, stdin) != EOF)
add_sought_entry(&sought, &nr_sought, &alloc_sought, line.buf);
strbuf_release(&line);
}
}
if (args.stateless_rpc) {
conn = NULL;
fd[0] = 0;
fd[1] = 1;
} else {
int flags = args.verbose ? CONNECT_VERBOSE : 0;
if (args.diag_url)
flags |= CONNECT_DIAG_URL;
conn = git_connect(fd, dest, args.uploadpack,
flags);
if (!conn)
return args.diag_url ? 0 : 1;
}
packet_reader_init(&reader, fd[0], NULL, 0,
PACKET_READ_CHOMP_NEWLINE |
PACKET_READ_GENTLE_ON_EOF |
PACKET_READ_DIE_ON_ERR_PACKET);
switch (discover_version(&reader)) {
case protocol_v2:
die("support for protocol v2 not implemented yet");
case protocol_v1:
case protocol_v0:
get_remote_heads(&reader, &ref, 0, NULL, &shallow);
break;
case protocol_unknown_version:
BUG("unknown protocol version");
}
ref = fetch_pack(&args, fd, conn, ref, dest, sought, nr_sought,
&shallow, pack_lockfile_ptr, protocol_v0);
if (pack_lockfile) {
printf("lock %s\n", pack_lockfile);
fflush(stdout);
}
if (args.check_self_contained_and_connected &&
args.self_contained_and_connected) {
printf("connectivity-ok\n");
fflush(stdout);
}
close(fd[0]);
close(fd[1]);
if (finish_connect(conn))
return 1;
ret = !ref;
/*
* If the heads to pull were given, we should have consumed
* all of them by matching the remote. Otherwise, 'git fetch
* remote no-such-ref' would silently succeed without issuing
* an error.
*/
ret |= report_unmatched_refs(sought, nr_sought);
while (ref) {
printf("%s %s\n",
oid_to_hex(&ref->old_oid), ref->name);
ref = ref->next;
}
return ret;
}