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937a515a15
git/upload-pack.c
Junio C Hamano 937a515a15 upload-pack: stop the other side when they have more roots than we do. 
When the downloader has more roots than we do, we will see many
"have" that leads to the root we do not have and let the other
side walk all the way to that root.  Tell them to stop sending the
branch'es ancestors by sending a fake "ACK" when we already have
common ancestor for the wanted refs.

Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-08-12 22:51:53 -07:00

596 lines
13 KiB
C
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#include <signal.h>
#include <sys/wait.h>
#include <sys/poll.h>
#include "cache.h"
#include "refs.h"
#include "pkt-line.h"
#include "tag.h"
#include "object.h"
#include "commit.h"
#include "exec_cmd.h"
static const char upload_pack_usage[] = "git-upload-pack [--strict] [--timeout=nn] <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)
static unsigned long oldest_have = 0;
static int multi_ack = 0, nr_our_refs = 0;
static int use_thin_pack = 0;
static struct object_array have_obj;
static struct object_array want_obj;
static unsigned int timeout = 0;
static int use_sideband = 0;
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;
}
#define PACKET_MAX 1000
static ssize_t send_client_data(int fd, const char *data, ssize_t sz)
{
ssize_t ssz;
const char *p;
if (!data) {
if (!use_sideband)
return 0;
packet_flush(1);
}
if (!use_sideband) {
if (fd == 3)
/* emergency quit */
fd = 2;
if (fd == 2) {
xwrite(fd, data, sz);
return sz;
}
return safe_write(fd, data, sz);
}
p = data;
ssz = sz;
while (sz) {
unsigned n;
char hdr[5];
n = sz;
if (PACKET_MAX - 5 < n)
n = PACKET_MAX - 5;
sprintf(hdr, "%04x", n + 5);
hdr[4] = fd;
safe_write(1, hdr, 5);
safe_write(1, p, n);
p += n;
sz -= n;
}
return ssz;
}
static void create_pack_file(void)
{
/* Pipes between rev-list to pack-objects, pack-objects to us
* and pack-objects error stream for progress bar.
*/
int lp_pipe[2], pu_pipe[2], pe_pipe[2];
pid_t pid_rev_list, pid_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;
if (pipe(lp_pipe) < 0)
die("git-upload-pack: unable to create pipe");
pid_rev_list = fork();
if (pid_rev_list < 0)
die("git-upload-pack: unable to fork git-rev-list");
if (!pid_rev_list) {
int i;
int args;
const char **argv;
const char **p;
char *buf;
if (create_full_pack) {
args = 10;
use_thin_pack = 0; /* no point doing it */
}
else
args = have_obj.nr + want_obj.nr + 5;
p = xmalloc(args * sizeof(char *));
argv = (const char **) p;
buf = xmalloc(args * 45);
dup2(lp_pipe[1], 1);
close(0);
close(lp_pipe[0]);
close(lp_pipe[1]);
*p++ = "rev-list";
*p++ = use_thin_pack ? "--objects-edge" : "--objects";
if (create_full_pack)
*p++ = "--all";
else {
for (i = 0; i < want_obj.nr; i++) {
struct object *o = want_obj.objects[i].item;
*p++ = buf;
memcpy(buf, sha1_to_hex(o->sha1), 41);
buf += 41;
}
}
if (!create_full_pack)
for (i = 0; i < have_obj.nr; i++) {
struct object *o = have_obj.objects[i].item;
*p++ = buf;
*buf++ = '^';
memcpy(buf, sha1_to_hex(o->sha1), 41);
buf += 41;
}
*p++ = NULL;
execv_git_cmd(argv);
die("git-upload-pack: unable to exec git-rev-list");
}
if (pipe(pu_pipe) < 0)
die("git-upload-pack: unable to create pipe");
if (pipe(pe_pipe) < 0)
die("git-upload-pack: unable to create pipe");
pid_pack_objects = fork();
if (pid_pack_objects < 0) {
/* daemon sets things up to ignore TERM */
kill(pid_rev_list, SIGKILL);
die("git-upload-pack: unable to fork git-pack-objects");
}
if (!pid_pack_objects) {
dup2(lp_pipe[0], 0);
dup2(pu_pipe[1], 1);
dup2(pe_pipe[1], 2);
close(lp_pipe[0]);
close(lp_pipe[1]);
close(pu_pipe[0]);
close(pu_pipe[1]);
close(pe_pipe[0]);
close(pe_pipe[1]);
execl_git_cmd("pack-objects", "--stdout", "--progress", NULL);
kill(pid_rev_list, SIGKILL);
die("git-upload-pack: unable to exec git-pack-objects");
}
close(lp_pipe[0]);
close(lp_pipe[1]);
/* We read from pe_pipe[0] to capture stderr output for
* progress bar, and pu_pipe[0] to capture the pack data.
*/
close(pe_pipe[1]);
close(pu_pipe[1]);
while (1) {
const char *who;
struct pollfd pfd[2];
pid_t pid;
int status;
ssize_t sz;
int pe, pu, pollsize;
reset_timeout();
pollsize = 0;
pe = pu = -1;
if (0 <= pu_pipe[0]) {
pfd[pollsize].fd = pu_pipe[0];
pfd[pollsize].events = POLLIN;
pu = pollsize;
pollsize++;
}
if (0 <= pe_pipe[0]) {
pfd[pollsize].fd = pe_pipe[0];
pfd[pollsize].events = POLLIN;
pe = pollsize;
pollsize++;
}
if (pollsize) {
if (poll(pfd, pollsize, -1) < 0) {
if (errno != EINTR) {
error("poll failed, resuming: %s",
strerror(errno));
sleep(1);
}
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 pack
* data 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 = read(pu_pipe[0], cp,
sizeof(data) - outsz);
if (0 < sz)
;
else if (sz == 0) {
close(pu_pipe[0]);
pu_pipe[0] = -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 (0 <= pe && (pfd[pe].revents & (POLLIN|POLLHUP))) {
/* Status ready; we ship that in the side-band
* or dump to the standard error.
*/
sz = read(pe_pipe[0], progress,
sizeof(progress));
if (0 < sz)
send_client_data(2, progress, sz);
else if (sz == 0) {
close(pe_pipe[0]);
pe_pipe[0] = -1;
}
else
goto fail;
}
}
/* See if the children are still there */
if (pid_rev_list || pid_pack_objects) {
pid = waitpid(-1, &status, WNOHANG);
if (!pid)
continue;
who = ((pid == pid_rev_list) ? "git-rev-list" :
(pid == pid_pack_objects) ? "git-pack-objects" :
NULL);
if (!who) {
if (pid < 0) {
error("git-upload-pack: %s",
strerror(errno));
goto fail;
}
error("git-upload-pack: we weren't "
"waiting for %d", pid);
continue;
}
if (!WIFEXITED(status) || WEXITSTATUS(status) > 0) {
error("git-upload-pack: %s died with error.",
who);
goto fail;
}
if (pid == pid_rev_list)
pid_rev_list = 0;
if (pid == pid_pack_objects)
pid_pack_objects = 0;
if (pid_rev_list || pid_pack_objects)
continue;
}
/* both died happily */
if (pollsize)
continue;
/* 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");
}
send_client_data(1, NULL, 0);
return;
}
fail:
if (pid_pack_objects)
kill(pid_pack_objects, SIGKILL);
if (pid_rev_list)
kill(pid_rev_list, SIGKILL);
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 = lookup_object(sha1);
if (!(o && o->parsed))
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;
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))
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 hex[41], last_hex[41];
int len;
track_object_refs = 0;
save_commit_buffer = 0;
for(;;) {
len = packet_read_line(0, line, sizeof(line));
reset_timeout();
if (!len) {
if (have_obj.nr == 0 || multi_ack)
packet_write(1, "NAK\n");
continue;
}
len = strip(line, len);
if (!strncmp(line, "have ", 5)) {
switch (got_sha1(line+5, sha1)) {
case -1: /* they have what we do not */
if (multi_ack && ok_to_give_up())
packet_write(1, "ACK %s continue\n",
sha1_to_hex(sha1));
break;
default:
memcpy(hex, sha1_to_hex(sha1), 41);
if (multi_ack) {
const char *msg = "ACK %s continue\n";
packet_write(1, msg, hex);
memcpy(last_hex, hex, 41);
}
else if (have_obj.nr == 1)
packet_write(1, "ACK %s\n", 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 receive_needs(void)
{
static char line[1000];
int len;
for (;;) {
struct object *o;
unsigned char sha1_buf[20];
len = packet_read_line(0, line, sizeof(line));
reset_timeout();
if (!len)
return;
if (strncmp("want ", line, 5) ||
get_sha1_hex(line+5, sha1_buf))
die("git-upload-pack: protocol error, "
"expected to get sha, not '%s'", line);
if (strstr(line+45, "multi_ack"))
multi_ack = 1;
if (strstr(line+45, "thin-pack"))
use_thin_pack = 1;
if (strstr(line+45, "side-band"))
use_sideband = 1;
/* We have sent all our refs already, and the other end
* should have chosen out of them; otherwise they are
* asking for nonsense.
*
* Hmph. We may later want to allow "want" line that
* asks for something like "master~10" (symbolic)...
* would it make sense? I don't know.
*/
o = lookup_object(sha1_buf);
if (!o || !(o->flags & OUR_REF))
die("git-upload-pack: not our ref %s", line+5);
if (!(o->flags & WANTED)) {
o->flags |= WANTED;
add_object_array(o, NULL, &want_obj);
}
}
}
static int send_ref(const char *refname, const unsigned char *sha1)
{
static const char *capabilities = "multi_ack thin-pack side-band";
struct object *o = parse_object(sha1);
if (!o)
die("git-upload-pack: cannot find object %s:", sha1_to_hex(sha1));
if (capabilities)
packet_write(1, "%s %s%c%s\n", sha1_to_hex(sha1), refname,
0, capabilities);
else
packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname);
capabilities = NULL;
if (!(o->flags & OUR_REF)) {
o->flags |= OUR_REF;
nr_our_refs++;
}
if (o->type == OBJ_TAG) {
o = deref_tag(o, refname, 0);
packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname);
}
return 0;
}
static int upload_pack(void)
{
reset_timeout();
head_ref(send_ref);
for_each_ref(send_ref);
packet_flush(1);
receive_needs();
if (!want_obj.nr)
return 0;
get_common_commits();
create_pack_file();
return 0;
}
int main(int argc, char **argv)
{
char *dir;
int i;
int strict = 0;
for (i = 1; i < argc; i++) {
char *arg = argv[i];
if (arg[0] != '-')
break;
if (!strcmp(arg, "--strict")) {
strict = 1;
continue;
}
if (!strncmp(arg, "--timeout=", 10)) {
timeout = atoi(arg+10);
continue;
}
if (!strcmp(arg, "--")) {
i++;
break;
}
}
if (i != argc-1)
usage(upload_pack_usage);
dir = argv[i];
if (!enter_repo(dir, strict))
die("'%s': unable to chdir or not a git archive", dir);
upload_pack();
return 0;
}
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