1
0
Fork 0
mirror of https://github.com/git/git.git synced 2024-11-06 09:13:01 +01:00
git/send-pack.c
Junio C Hamano e40a9e2c9e send-pack: fix pipeline.
send-pack builds a pipeline that runs "rev-list | pack-objects"
and sends the output from pack-objects to the other side, while
feeding the input side of that pipe from itself.  However, the
file descriptor that is given to this pipeline (so that it can
be dup2(2)'ed into file descriptor 1 of pack-objects) is closed
by the caller before the complex fork+exec dance!  Worse yet,
the caller already dup2's it to 1, so the child process did not
even have to.

I do not understand how this code could possibly have been
working, but it somehow was working by accident.

Merging the sliding mmap() code reveals this problem, presumably
because it keeps one extra file descriptor open for a packfile
and changes the way file descriptors are allocated.  I am too
tired to diagnose the problem now, but this seems to be a
sensible fix.

Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-12-29 11:37:01 -08:00

486 lines
11 KiB
C

#include "cache.h"
#include "commit.h"
#include "tag.h"
#include "refs.h"
#include "pkt-line.h"
#include "exec_cmd.h"
static const char send_pack_usage[] =
"git-send-pack [--all] [--exec=git-receive-pack] <remote> [<head>...]\n"
" --all and explicit <head> specification are mutually exclusive.";
static const char *exec = "git-receive-pack";
static int verbose;
static int send_all;
static int force_update;
static int use_thin_pack;
static int is_zero_sha1(const unsigned char *sha1)
{
int i;
for (i = 0; i < 20; i++) {
if (*sha1++)
return 0;
}
return 1;
}
static void exec_pack_objects(void)
{
static const char *args[] = {
"pack-objects",
"--all-progress",
"--stdout",
NULL
};
execv_git_cmd(args);
die("git-pack-objects exec failed (%s)", strerror(errno));
}
static void exec_rev_list(struct ref *refs)
{
static const char *args[4];
int i = 0;
args[i++] = "rev-list"; /* 0 */
if (use_thin_pack) /* 1 */
args[i++] = "--objects-edge";
else
args[i++] = "--objects";
args[i++] = "--stdin";
args[i] = NULL;
execv_git_cmd(args);
die("git-rev-list exec failed (%s)", strerror(errno));
}
/*
* Run "rev-list --stdin | pack-objects" pipe.
*/
static void rev_list(struct ref *refs)
{
int pipe_fd[2];
pid_t pack_objects_pid;
if (pipe(pipe_fd) < 0)
die("rev-list setup: pipe failed");
pack_objects_pid = fork();
if (!pack_objects_pid) {
/* The child becomes pack-objects; reads from pipe
* and writes to the original fd
*/
dup2(pipe_fd[0], 0);
close(pipe_fd[0]);
close(pipe_fd[1]);
exec_pack_objects();
die("pack-objects setup failed");
}
if (pack_objects_pid < 0)
die("pack-objects fork failed");
/* We become rev-list --stdin; output goes to pipe. */
dup2(pipe_fd[1], 1);
close(pipe_fd[0]);
close(pipe_fd[1]);
exec_rev_list(refs);
}
/*
* Create "rev-list --stdin | pack-objects" pipe and feed
* the refs into the pipeline.
*/
static void rev_list_generate(int fd, struct ref *refs)
{
int pipe_fd[2];
pid_t rev_list_generate_pid;
if (pipe(pipe_fd) < 0)
die("rev-list-generate setup: pipe failed");
rev_list_generate_pid = fork();
if (!rev_list_generate_pid) {
/* The child becomes the "rev-list | pack-objects"
* pipeline. It takes input from us, and its output
* goes to fd.
*/
dup2(pipe_fd[0], 0);
dup2(fd, 1);
close(pipe_fd[0]);
close(pipe_fd[1]);
close(fd);
rev_list(refs);
die("rev-list setup failed");
}
if (rev_list_generate_pid < 0)
die("rev-list-generate fork failed");
/* We feed the rev parameters to them. We do not write into
* fd nor read from the pipe.
*/
close(pipe_fd[0]);
close(fd);
while (refs) {
char buf[42];
if (!is_null_sha1(refs->old_sha1) &&
has_sha1_file(refs->old_sha1)) {
memcpy(buf + 1, sha1_to_hex(refs->old_sha1), 40);
buf[0] = '^';
buf[41] = '\n';
write(pipe_fd[1], buf, 42);
}
if (!is_null_sha1(refs->new_sha1)) {
memcpy(buf, sha1_to_hex(refs->new_sha1), 40);
buf[40] = '\n';
write(pipe_fd[1], buf, 41);
}
refs = refs->next;
}
close(pipe_fd[1]);
// waitpid(rev_list_generate_pid);
exit(0);
}
/*
* Make a pack stream and spit it out into file descriptor fd
*/
static void pack_objects(int fd, struct ref *refs)
{
pid_t rev_list_pid;
rev_list_pid = fork();
if (!rev_list_pid) {
rev_list_generate(fd, refs);
die("rev-list setup failed");
}
if (rev_list_pid < 0)
die("rev-list fork failed");
/*
* We don't wait for the rev-list pipeline in the parent:
* we end up waiting for the other end instead
*/
}
static void unmark_and_free(struct commit_list *list, unsigned int mark)
{
while (list) {
struct commit_list *temp = list;
temp->item->object.flags &= ~mark;
list = temp->next;
free(temp);
}
}
static int ref_newer(const unsigned char *new_sha1,
const unsigned char *old_sha1)
{
struct object *o;
struct commit *old, *new;
struct commit_list *list, *used;
int found = 0;
/* Both new and old must be commit-ish and new is descendant of
* old. Otherwise we require --force.
*/
o = deref_tag(parse_object(old_sha1), NULL, 0);
if (!o || o->type != OBJ_COMMIT)
return 0;
old = (struct commit *) o;
o = deref_tag(parse_object(new_sha1), NULL, 0);
if (!o || o->type != OBJ_COMMIT)
return 0;
new = (struct commit *) o;
if (parse_commit(new) < 0)
return 0;
used = list = NULL;
commit_list_insert(new, &list);
while (list) {
new = pop_most_recent_commit(&list, 1);
commit_list_insert(new, &used);
if (new == old) {
found = 1;
break;
}
}
unmark_and_free(list, 1);
unmark_and_free(used, 1);
return found;
}
static struct ref *local_refs, **local_tail;
static struct ref *remote_refs, **remote_tail;
static int one_local_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
{
struct ref *ref;
int len = strlen(refname) + 1;
ref = xcalloc(1, sizeof(*ref) + len);
hashcpy(ref->new_sha1, sha1);
memcpy(ref->name, refname, len);
*local_tail = ref;
local_tail = &ref->next;
return 0;
}
static void get_local_heads(void)
{
local_tail = &local_refs;
for_each_ref(one_local_ref, NULL);
}
static int receive_status(int in)
{
char line[1000];
int ret = 0;
int len = packet_read_line(in, line, sizeof(line));
if (len < 10 || memcmp(line, "unpack ", 7)) {
fprintf(stderr, "did not receive status back\n");
return -1;
}
if (memcmp(line, "unpack ok\n", 10)) {
fputs(line, stderr);
ret = -1;
}
while (1) {
len = packet_read_line(in, line, sizeof(line));
if (!len)
break;
if (len < 3 ||
(memcmp(line, "ok", 2) && memcmp(line, "ng", 2))) {
fprintf(stderr, "protocol error: %s\n", line);
ret = -1;
break;
}
if (!memcmp(line, "ok", 2))
continue;
fputs(line, stderr);
ret = -1;
}
return ret;
}
static int send_pack(int in, int out, int nr_refspec, char **refspec)
{
struct ref *ref;
int new_refs;
int ret = 0;
int ask_for_status_report = 0;
int allow_deleting_refs = 0;
int expect_status_report = 0;
/* No funny business with the matcher */
remote_tail = get_remote_heads(in, &remote_refs, 0, NULL, REF_NORMAL);
get_local_heads();
/* Does the other end support the reporting? */
if (server_supports("report-status"))
ask_for_status_report = 1;
if (server_supports("delete-refs"))
allow_deleting_refs = 1;
/* match them up */
if (!remote_tail)
remote_tail = &remote_refs;
if (match_refs(local_refs, remote_refs, &remote_tail,
nr_refspec, refspec, send_all))
return -1;
if (!remote_refs) {
fprintf(stderr, "No refs in common and none specified; doing nothing.\n");
return 0;
}
/*
* Finally, tell the other end!
*/
new_refs = 0;
for (ref = remote_refs; ref; ref = ref->next) {
char old_hex[60], *new_hex;
int delete_ref;
if (!ref->peer_ref)
continue;
delete_ref = is_null_sha1(ref->peer_ref->new_sha1);
if (delete_ref && !allow_deleting_refs) {
error("remote does not support deleting refs");
ret = -2;
continue;
}
if (!delete_ref &&
!hashcmp(ref->old_sha1, ref->peer_ref->new_sha1)) {
if (verbose)
fprintf(stderr, "'%s': up-to-date\n", ref->name);
continue;
}
/* This part determines what can overwrite what.
* The rules are:
*
* (0) you can always use --force or +A:B notation to
* selectively force individual ref pairs.
*
* (1) if the old thing does not exist, it is OK.
*
* (2) if you do not have the old thing, you are not allowed
* to overwrite it; you would not know what you are losing
* otherwise.
*
* (3) if both new and old are commit-ish, and new is a
* descendant of old, it is OK.
*
* (4) regardless of all of the above, removing :B is
* always allowed.
*/
if (!force_update &&
!delete_ref &&
!is_zero_sha1(ref->old_sha1) &&
!ref->force) {
if (!has_sha1_file(ref->old_sha1) ||
!ref_newer(ref->peer_ref->new_sha1,
ref->old_sha1)) {
/* We do not have the remote ref, or
* we know that the remote ref is not
* an ancestor of what we are trying to
* push. Either way this can be losing
* commits at the remote end and likely
* we were not up to date to begin with.
*/
error("remote '%s' is not a strict "
"subset of local ref '%s'. "
"maybe you are not up-to-date and "
"need to pull first?",
ref->name,
ref->peer_ref->name);
ret = -2;
continue;
}
}
hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
if (!delete_ref)
new_refs++;
strcpy(old_hex, sha1_to_hex(ref->old_sha1));
new_hex = sha1_to_hex(ref->new_sha1);
if (ask_for_status_report) {
packet_write(out, "%s %s %s%c%s",
old_hex, new_hex, ref->name, 0,
"report-status");
ask_for_status_report = 0;
expect_status_report = 1;
}
else
packet_write(out, "%s %s %s",
old_hex, new_hex, ref->name);
if (delete_ref)
fprintf(stderr, "deleting '%s'\n", ref->name);
else {
fprintf(stderr, "updating '%s'", ref->name);
if (strcmp(ref->name, ref->peer_ref->name))
fprintf(stderr, " using '%s'",
ref->peer_ref->name);
fprintf(stderr, "\n from %s\n to %s\n",
old_hex, new_hex);
}
}
packet_flush(out);
if (new_refs)
pack_objects(out, remote_refs);
close(out);
if (expect_status_report) {
if (receive_status(in))
ret = -4;
}
if (!new_refs && ret == 0)
fprintf(stderr, "Everything up-to-date\n");
return ret;
}
static void verify_remote_names(int nr_heads, char **heads)
{
int i;
for (i = 0; i < nr_heads; i++) {
const char *remote = strchr(heads[i], ':');
remote = remote ? (remote + 1) : heads[i];
switch (check_ref_format(remote)) {
case 0: /* ok */
case -2: /* ok but a single level -- that is fine for
* a match pattern.
*/
continue;
}
die("remote part of refspec is not a valid name in %s",
heads[i]);
}
}
int main(int argc, char **argv)
{
int i, nr_heads = 0;
char *dest = NULL;
char **heads = NULL;
int fd[2], ret;
pid_t pid;
setup_git_directory();
git_config(git_default_config);
argv++;
for (i = 1; i < argc; i++, argv++) {
char *arg = *argv;
if (*arg == '-') {
if (!strncmp(arg, "--exec=", 7)) {
exec = arg + 7;
continue;
}
if (!strcmp(arg, "--all")) {
send_all = 1;
continue;
}
if (!strcmp(arg, "--force")) {
force_update = 1;
continue;
}
if (!strcmp(arg, "--verbose")) {
verbose = 1;
continue;
}
if (!strcmp(arg, "--thin")) {
use_thin_pack = 1;
continue;
}
usage(send_pack_usage);
}
if (!dest) {
dest = arg;
continue;
}
heads = argv;
nr_heads = argc - i;
break;
}
if (!dest)
usage(send_pack_usage);
if (heads && send_all)
usage(send_pack_usage);
verify_remote_names(nr_heads, heads);
pid = git_connect(fd, dest, exec);
if (pid < 0)
return 1;
ret = send_pack(fd[0], fd[1], nr_heads, heads);
close(fd[0]);
close(fd[1]);
ret |= finish_connect(pid);
return !!ret;
}