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git/send-pack.c
Michal Ostrowski 77cb17e940 Exec git programs without using PATH. 
The git suite may not be in PATH (and thus programs such as
git-send-pack could not exec git-rev-list).  Thus there is a need for
logic that will locate these programs.  Modifying PATH is not
desirable as it result in behavior differing from the user's
intentions, as we may end up prepending "/usr/bin" to PATH.

- git C programs will use exec*_git_cmd() APIs to exec sub-commands.
- exec*_git_cmd() will execute a git program by searching for it in
  the following directories:
	1. --exec-path (as used by "git")
	2. The GIT_EXEC_PATH environment variable.
	3. $(gitexecdir) as set in Makefile (default value $(bindir)).
- git wrapper will modify PATH as before to enable shell scripts to
  invoke "git-foo" commands.

Ideally, shell scripts should use the git wrapper to become independent
of PATH, and then modifying PATH will not be necessary.

[jc: with minor updates after a brief review.]

Signed-off-by: Michal Ostrowski <mostrows@watson.ibm.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-01-13 16:49:01 -08:00

387 lines
8.5 KiB
C
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#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 = 0;
static int send_all = 0;
static int force_update = 0;
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 char *args[] = {
"pack-objects",
"--stdout",
NULL
};
execv_git_cmd(args);
die("git-pack-objects exec failed (%s)", strerror(errno));
}
static void exec_rev_list(struct ref *refs)
{
static char *args[1000];
int i = 0;
args[i++] = "rev-list"; /* 0 */
args[i++] = "--objects"; /* 1 */
while (refs) {
char *buf = malloc(100);
if (i > 900)
die("git-rev-list environment overflow");
if (!is_zero_sha1(refs->old_sha1) &&
has_sha1_file(refs->old_sha1)) {
args[i++] = buf;
snprintf(buf, 50, "^%s", sha1_to_hex(refs->old_sha1));
buf += 50;
}
if (!is_zero_sha1(refs->new_sha1)) {
args[i++] = buf;
snprintf(buf, 50, "%s", sha1_to_hex(refs->new_sha1));
}
refs = refs->next;
}
args[i] = NULL;
execv_git_cmd(args);
die("git-rev-list exec failed (%s)", strerror(errno));
}
static void rev_list(int fd, 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) {
dup2(pipe_fd[0], 0);
dup2(fd, 1);
close(pipe_fd[0]);
close(pipe_fd[1]);
close(fd);
exec_pack_objects();
die("pack-objects setup failed");
}
if (pack_objects_pid < 0)
die("pack-objects fork failed");
dup2(pipe_fd[1], 1);
close(pipe_fd[0]);
close(pipe_fd[1]);
close(fd);
exec_rev_list(refs);
}
static int pack_objects(int fd, struct ref *refs)
{
pid_t rev_list_pid;
rev_list_pid = fork();
if (!rev_list_pid) {
rev_list(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
*/
return 0;
}
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 != commit_type)
return 0;
old = (struct commit *) o;
o = deref_tag(parse_object(new_sha1), NULL, 0);
if (!o || o->type != commit_type)
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)
{
struct ref *ref;
int len = strlen(refname) + 1;
ref = xcalloc(1, sizeof(*ref) + len);
memcpy(ref->new_sha1, sha1, 20);
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);
}
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 expect_status_report = 0;
/* No funny business with the matcher */
remote_tail = get_remote_heads(in, &remote_refs, 0, NULL, 1);
get_local_heads();
/* Does the other end support the reporting? */
if (server_supports("report-status"))
ask_for_status_report = 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;
if (!ref->peer_ref)
continue;
if (!memcmp(ref->old_sha1, ref->peer_ref->new_sha1, 20)) {
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.
*/
if (!force_update &&
!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;
}
}
memcpy(ref->new_sha1, ref->peer_ref->new_sha1, 20);
if (is_zero_sha1(ref->new_sha1)) {
error("cannot happen anymore");
ret = -3;
continue;
}
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);
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;
}
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();
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;
}
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);
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]);
finish_connect(pid);
return ret;
}
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