git/builtin/archive.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

113 lines
3.1 KiB
C

/*
* Copyright (c) 2006 Franck Bui-Huu
* Copyright (c) 2006 Rene Scharfe
*/
#include "cache.h"
#include "builtin.h"
#include "archive.h"
#include "transport.h"
#include "parse-options.h"
#include "pkt-line.h"
#include "sideband.h"
static void create_output_file(const char *output_file)
{
int output_fd = open(output_file, O_CREAT | O_WRONLY | O_TRUNC, 0666);
if (output_fd < 0)
die_errno(_("could not create archive file '%s'"), output_file);
if (output_fd != 1) {
if (dup2(output_fd, 1) < 0)
die_errno(_("could not redirect output"));
else
close(output_fd);
}
}
static int run_remote_archiver(int argc, const char **argv,
const char *remote, const char *exec,
const char *name_hint)
{
int fd[2], i, rv;
struct transport *transport;
struct remote *_remote;
struct packet_reader reader;
_remote = remote_get(remote);
if (!_remote->url[0])
die(_("git archive: Remote with no URL"));
transport = transport_get(_remote, _remote->url[0]);
transport_connect(transport, "git-upload-archive", exec, fd);
/*
* Inject a fake --format field at the beginning of the
* arguments, with the format inferred from our output
* filename. This way explicit --format options can override
* it.
*/
if (name_hint) {
const char *format = archive_format_from_filename(name_hint);
if (format)
packet_write_fmt(fd[1], "argument --format=%s\n", format);
}
for (i = 1; i < argc; i++)
packet_write_fmt(fd[1], "argument %s\n", argv[i]);
packet_flush(fd[1]);
packet_reader_init(&reader, fd[0], NULL, 0,
PACKET_READ_CHOMP_NEWLINE |
PACKET_READ_DIE_ON_ERR_PACKET);
if (packet_reader_read(&reader) != PACKET_READ_NORMAL)
die(_("git archive: expected ACK/NAK, got a flush packet"));
if (strcmp(reader.line, "ACK")) {
if (starts_with(reader.line, "NACK "))
die(_("git archive: NACK %s"), reader.line + 5);
die(_("git archive: protocol error"));
}
if (packet_reader_read(&reader) != PACKET_READ_FLUSH)
die(_("git archive: expected a flush"));
/* Now, start reading from fd[0] and spit it out to stdout */
rv = recv_sideband("archive", fd[0], 1);
rv |= transport_disconnect(transport);
return !!rv;
}
#define PARSE_OPT_KEEP_ALL ( PARSE_OPT_KEEP_DASHDASH | \
PARSE_OPT_KEEP_ARGV0 | \
PARSE_OPT_KEEP_UNKNOWN | \
PARSE_OPT_NO_INTERNAL_HELP )
int cmd_archive(int argc, const char **argv, const char *prefix)
{
const char *exec = "git-upload-archive";
const char *output = NULL;
const char *remote = NULL;
struct option local_opts[] = {
OPT_FILENAME('o', "output", &output,
N_("write the archive to this file")),
OPT_STRING(0, "remote", &remote, N_("repo"),
N_("retrieve the archive from remote repository <repo>")),
OPT_STRING(0, "exec", &exec, N_("command"),
N_("path to the remote git-upload-archive command")),
OPT_END()
};
argc = parse_options(argc, argv, prefix, local_opts, NULL,
PARSE_OPT_KEEP_ALL);
init_archivers();
if (output)
create_output_file(output);
if (remote)
return run_remote_archiver(argc, argv, remote, exec, output);
setvbuf(stderr, NULL, _IOLBF, BUFSIZ);
return write_archive(argc, argv, prefix, the_repository, output, 0);
}