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git/send-pack.c
Jeff King 74543a0423 pkt-line: provide a LARGE_PACKET_MAX static buffer
Most of the callers of packet_read_line just read into a
static 1000-byte buffer (callers which handle arbitrary
binary data already use LARGE_PACKET_MAX). This works fine
in practice, because:

  1. The only variable-sized data in these lines is a ref
     name, and refs tend to be a lot shorter than 1000
     characters.

  2. When sending ref lines, git-core always limits itself
     to 1000 byte packets.

However, the only limit given in the protocol specification
in Documentation/technical/protocol-common.txt is
LARGE_PACKET_MAX; the 1000 byte limit is mentioned only in
pack-protocol.txt, and then only describing what we write,
not as a specific limit for readers.

This patch lets us bump the 1000-byte limit to
LARGE_PACKET_MAX. Even though git-core will never write a
packet where this makes a difference, there are two good
reasons to do this:

  1. Other git implementations may have followed
     protocol-common.txt and used a larger maximum size. We
     don't bump into it in practice because it would involve
     very long ref names.

  2. We may want to increase the 1000-byte limit one day.
     Since packets are transferred before any capabilities,
     it's difficult to do this in a backwards-compatible
     way. But if we bump the size of buffer the readers can
     handle, eventually older versions of git will be
     obsolete enough that we can justify bumping the
     writers, as well. We don't have plans to do this
     anytime soon, but there is no reason not to start the
     clock ticking now.

Just bumping all of the reading bufs to LARGE_PACKET_MAX
would waste memory. Instead, since most readers just read
into a temporary buffer anyway, let's provide a single
static buffer that all callers can use. We can further wrap
this detail away by having the packet_read_line wrapper just
use the buffer transparently and return a pointer to the
static storage.  That covers most of the cases, and the
remaining ones already read into their own LARGE_PACKET_MAX
buffers.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-02-20 13:42:22 -08:00

341 lines
7.6 KiB
C

#include "builtin.h"
#include "commit.h"
#include "refs.h"
#include "pkt-line.h"
#include "sideband.h"
#include "run-command.h"
#include "remote.h"
#include "send-pack.h"
#include "quote.h"
#include "transport.h"
#include "version.h"
static int feed_object(const unsigned char *sha1, int fd, int negative)
{
char buf[42];
if (negative && !has_sha1_file(sha1))
return 1;
memcpy(buf + negative, sha1_to_hex(sha1), 40);
if (negative)
buf[0] = '^';
buf[40 + negative] = '\n';
return write_or_whine(fd, buf, 41 + negative, "send-pack: send refs");
}
/*
* Make a pack stream and spit it out into file descriptor fd
*/
static int pack_objects(int fd, struct ref *refs, struct extra_have_objects *extra, struct send_pack_args *args)
{
/*
* The child becomes pack-objects --revs; we feed
* the revision parameters to it via its stdin and
* let its stdout go back to the other end.
*/
const char *argv[] = {
"pack-objects",
"--all-progress-implied",
"--revs",
"--stdout",
NULL,
NULL,
NULL,
NULL,
NULL,
};
struct child_process po;
int i;
i = 4;
if (args->use_thin_pack)
argv[i++] = "--thin";
if (args->use_ofs_delta)
argv[i++] = "--delta-base-offset";
if (args->quiet || !args->progress)
argv[i++] = "-q";
if (args->progress)
argv[i++] = "--progress";
memset(&po, 0, sizeof(po));
po.argv = argv;
po.in = -1;
po.out = args->stateless_rpc ? -1 : fd;
po.git_cmd = 1;
if (start_command(&po))
die_errno("git pack-objects failed");
/*
* We feed the pack-objects we just spawned with revision
* parameters by writing to the pipe.
*/
for (i = 0; i < extra->nr; i++)
if (!feed_object(extra->array[i], po.in, 1))
break;
while (refs) {
if (!is_null_sha1(refs->old_sha1) &&
!feed_object(refs->old_sha1, po.in, 1))
break;
if (!is_null_sha1(refs->new_sha1) &&
!feed_object(refs->new_sha1, po.in, 0))
break;
refs = refs->next;
}
close(po.in);
if (args->stateless_rpc) {
char *buf = xmalloc(LARGE_PACKET_MAX);
while (1) {
ssize_t n = xread(po.out, buf, LARGE_PACKET_MAX);
if (n <= 0)
break;
send_sideband(fd, -1, buf, n, LARGE_PACKET_MAX);
}
free(buf);
close(po.out);
po.out = -1;
}
if (finish_command(&po))
return -1;
return 0;
}
static int receive_status(int in, struct ref *refs)
{
struct ref *hint;
int ret = 0;
char *line = packet_read_line(in, NULL);
if (prefixcmp(line, "unpack "))
return error("did not receive remote status");
if (strcmp(line, "unpack ok")) {
error("unpack failed: %s", line + 7);
ret = -1;
}
hint = NULL;
while (1) {
char *refname;
char *msg;
line = packet_read_line(in, NULL);
if (!line)
break;
if (prefixcmp(line, "ok ") && prefixcmp(line, "ng ")) {
error("invalid ref status from remote: %s", line);
ret = -1;
break;
}
refname = line + 3;
msg = strchr(refname, ' ');
if (msg)
*msg++ = '\0';
/* first try searching at our hint, falling back to all refs */
if (hint)
hint = find_ref_by_name(hint, refname);
if (!hint)
hint = find_ref_by_name(refs, refname);
if (!hint) {
warning("remote reported status on unknown ref: %s",
refname);
continue;
}
if (hint->status != REF_STATUS_EXPECTING_REPORT) {
warning("remote reported status on unexpected ref: %s",
refname);
continue;
}
if (line[0] == 'o' && line[1] == 'k')
hint->status = REF_STATUS_OK;
else {
hint->status = REF_STATUS_REMOTE_REJECT;
ret = -1;
}
if (msg)
hint->remote_status = xstrdup(msg);
/* start our next search from the next ref */
hint = hint->next;
}
return ret;
}
static int sideband_demux(int in, int out, void *data)
{
int *fd = data, ret;
#ifdef NO_PTHREADS
close(fd[1]);
#endif
ret = recv_sideband("send-pack", fd[0], out);
close(out);
return ret;
}
int send_pack(struct send_pack_args *args,
int fd[], struct child_process *conn,
struct ref *remote_refs,
struct extra_have_objects *extra_have)
{
int in = fd[0];
int out = fd[1];
struct strbuf req_buf = STRBUF_INIT;
struct ref *ref;
int new_refs;
int allow_deleting_refs = 0;
int status_report = 0;
int use_sideband = 0;
int quiet_supported = 0;
int agent_supported = 0;
unsigned cmds_sent = 0;
int ret;
struct async demux;
/* Does the other end support the reporting? */
if (server_supports("report-status"))
status_report = 1;
if (server_supports("delete-refs"))
allow_deleting_refs = 1;
if (server_supports("ofs-delta"))
args->use_ofs_delta = 1;
if (server_supports("side-band-64k"))
use_sideband = 1;
if (server_supports("quiet"))
quiet_supported = 1;
if (server_supports("agent"))
agent_supported = 1;
if (!remote_refs) {
fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
"Perhaps you should specify a branch such as 'master'.\n");
return 0;
}
/*
* Finally, tell the other end!
*/
new_refs = 0;
for (ref = remote_refs; ref; ref = ref->next) {
if (!ref->peer_ref && !args->send_mirror)
continue;
/* Check for statuses set by set_ref_status_for_push() */
switch (ref->status) {
case REF_STATUS_REJECT_NONFASTFORWARD:
case REF_STATUS_REJECT_ALREADY_EXISTS:
case REF_STATUS_REJECT_FETCH_FIRST:
case REF_STATUS_REJECT_NEEDS_FORCE:
case REF_STATUS_UPTODATE:
continue;
default:
; /* do nothing */
}
if (ref->deletion && !allow_deleting_refs) {
ref->status = REF_STATUS_REJECT_NODELETE;
continue;
}
if (!ref->deletion)
new_refs++;
if (args->dry_run) {
ref->status = REF_STATUS_OK;
} else {
char *old_hex = sha1_to_hex(ref->old_sha1);
char *new_hex = sha1_to_hex(ref->new_sha1);
int quiet = quiet_supported && (args->quiet || !args->progress);
if (!cmds_sent && (status_report || use_sideband ||
quiet || agent_supported)) {
packet_buf_write(&req_buf,
"%s %s %s%c%s%s%s%s%s",
old_hex, new_hex, ref->name, 0,
status_report ? " report-status" : "",
use_sideband ? " side-band-64k" : "",
quiet ? " quiet" : "",
agent_supported ? " agent=" : "",
agent_supported ? git_user_agent_sanitized() : ""
);
}
else
packet_buf_write(&req_buf, "%s %s %s",
old_hex, new_hex, ref->name);
ref->status = status_report ?
REF_STATUS_EXPECTING_REPORT :
REF_STATUS_OK;
cmds_sent++;
}
}
if (args->stateless_rpc) {
if (!args->dry_run && cmds_sent) {
packet_buf_flush(&req_buf);
send_sideband(out, -1, req_buf.buf, req_buf.len, LARGE_PACKET_MAX);
}
} else {
write_or_die(out, req_buf.buf, req_buf.len);
packet_flush(out);
}
strbuf_release(&req_buf);
if (use_sideband && cmds_sent) {
memset(&demux, 0, sizeof(demux));
demux.proc = sideband_demux;
demux.data = fd;
demux.out = -1;
if (start_async(&demux))
die("send-pack: unable to fork off sideband demultiplexer");
in = demux.out;
}
if (new_refs && cmds_sent) {
if (pack_objects(out, remote_refs, extra_have, args) < 0) {
for (ref = remote_refs; ref; ref = ref->next)
ref->status = REF_STATUS_NONE;
if (args->stateless_rpc)
close(out);
if (git_connection_is_socket(conn))
shutdown(fd[0], SHUT_WR);
if (use_sideband)
finish_async(&demux);
return -1;
}
}
if (args->stateless_rpc && cmds_sent)
packet_flush(out);
if (status_report && cmds_sent)
ret = receive_status(in, remote_refs);
else
ret = 0;
if (args->stateless_rpc)
packet_flush(out);
if (use_sideband && cmds_sent) {
if (finish_async(&demux)) {
error("error in sideband demultiplexer");
ret = -1;
}
close(demux.out);
}
if (ret < 0)
return ret;
if (args->porcelain)
return 0;
for (ref = remote_refs; ref; ref = ref->next) {
switch (ref->status) {
case REF_STATUS_NONE:
case REF_STATUS_UPTODATE:
case REF_STATUS_OK:
break;
default:
return -1;
}
}
return 0;
}