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#include "cache.h"
#include "transport.h"
#include "quote.h"
#include "run-command.h"
#include "commit.h"
#include "diff.h"
#include "revision.h"
#include "quote.h"
#include "remote.h"
#include "string-list.h"
#include "thread-utils.h"
#include "sigchain.h"
static int debug;
struct helper_data {
const char *name;
struct child_process *helper;
FILE *out;
unsigned fetch : 1,
import : 1,
export : 1,
option : 1,
push : 1,
connect : 1,
no_disconnect_req : 1;
char *export_marks;
char *import_marks;
/* These go from remote name (as in "list") to private name */
struct refspec *refspecs;
int refspec_nr;
/* Transport options for fetch-pack/send-pack (should one of
* those be invoked).
*/
struct git_transport_options transport_options;
};
static void sendline(struct helper_data *helper, struct strbuf *buffer)
{
if (debug)
fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
if (write_in_full(helper->helper->in, buffer->buf, buffer->len)
!= buffer->len)
die_errno("Full write to remote helper failed");
}
static int recvline_fh(FILE *helper, struct strbuf *buffer)
{
strbuf_reset(buffer);
if (debug)
fprintf(stderr, "Debug: Remote helper: Waiting...\n");
if (strbuf_getline(buffer, helper, '\n') == EOF) {
if (debug)
fprintf(stderr, "Debug: Remote helper quit.\n");
exit(128);
}
if (debug)
fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
return 0;
}
static int recvline(struct helper_data *helper, struct strbuf *buffer)
{
return recvline_fh(helper->out, buffer);
}
static void xchgline(struct helper_data *helper, struct strbuf *buffer)
{
sendline(helper, buffer);
recvline(helper, buffer);
}
static void write_constant(int fd, const char *str)
{
if (debug)
fprintf(stderr, "Debug: Remote helper: -> %s", str);
if (write_in_full(fd, str, strlen(str)) != strlen(str))
die_errno("Full write to remote helper failed");
}
static const char *remove_ext_force(const char *url)
{
if (url) {
const char *colon = strchr(url, ':');
if (colon && colon[1] == ':')
return colon + 2;
}
return url;
}
static void do_take_over(struct transport *transport)
{
struct helper_data *data;
data = (struct helper_data *)transport->data;
transport_take_over(transport, data->helper);
fclose(data->out);
free(data);
}
static struct child_process *get_helper(struct transport *transport)
{
struct helper_data *data = transport->data;
struct strbuf buf = STRBUF_INIT;
struct child_process *helper;
const char **refspecs = NULL;
int refspec_nr = 0;
int refspec_alloc = 0;
int duped;
int code;
char git_dir_buf[sizeof(GIT_DIR_ENVIRONMENT) + PATH_MAX + 1];
const char *helper_env[] = {
git_dir_buf,
NULL
};
if (data->helper)
return data->helper;
helper = xcalloc(1, sizeof(*helper));
helper->in = -1;
helper->out = -1;
helper->err = 0;
helper->argv = xcalloc(4, sizeof(*helper->argv));
strbuf_addf(&buf, "git-remote-%s", data->name);
helper->argv[0] = strbuf_detach(&buf, NULL);
helper->argv[1] = transport->remote->name;
helper->argv[2] = remove_ext_force(transport->url);
helper->git_cmd = 0;
helper->silent_exec_failure = 1;
snprintf(git_dir_buf, sizeof(git_dir_buf), "%s=%s", GIT_DIR_ENVIRONMENT, get_git_dir());
helper->env = helper_env;
code = start_command(helper);
if (code < 0 && errno == ENOENT)
die("Unable to find remote helper for '%s'", data->name);
else if (code != 0)
exit(code);
data->helper = helper;
data->no_disconnect_req = 0;
/*
* Open the output as FILE* so strbuf_getline() can be used.
* Do this with duped fd because fclose() will close the fd,
* and stuff like taking over will require the fd to remain.
*/
duped = dup(helper->out);
if (duped < 0)
die_errno("Can't dup helper output fd");
data->out = xfdopen(duped, "r");
write_constant(helper->in, "capabilities\n");
while (1) {
const char *capname;
int mandatory = 0;
recvline(data, &buf);
if (!*buf.buf)
break;
if (*buf.buf == '*') {
capname = buf.buf + 1;
mandatory = 1;
} else
capname = buf.buf;
if (debug)
fprintf(stderr, "Debug: Got cap %s\n", capname);
if (!strcmp(capname, "fetch"))
data->fetch = 1;
else if (!strcmp(capname, "option"))
data->option = 1;
else if (!strcmp(capname, "push"))
data->push = 1;
else if (!strcmp(capname, "import"))
data->import = 1;
else if (!strcmp(capname, "export"))
data->export = 1;
else if (!data->refspecs && !prefixcmp(capname, "refspec ")) {
ALLOC_GROW(refspecs,
refspec_nr + 1,
refspec_alloc);
refspecs[refspec_nr++] = xstrdup(capname + strlen("refspec "));
} else if (!strcmp(capname, "connect")) {
data->connect = 1;
} else if (!prefixcmp(capname, "export-marks ")) {
struct strbuf arg = STRBUF_INIT;
strbuf_addstr(&arg, "--export-marks=");
strbuf_addstr(&arg, capname + strlen("export-marks "));
data->export_marks = strbuf_detach(&arg, NULL);
} else if (!prefixcmp(capname, "import-marks")) {
struct strbuf arg = STRBUF_INIT;
strbuf_addstr(&arg, "--import-marks=");
strbuf_addstr(&arg, capname + strlen("import-marks "));
data->import_marks = strbuf_detach(&arg, NULL);
} else if (mandatory) {
die("Unknown mandatory capability %s. This remote "
"helper probably needs newer version of Git.",
capname);
}
}
if (refspecs) {
int i;
data->refspec_nr = refspec_nr;
data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
for (i = 0; i < refspec_nr; i++) {
free((char *)refspecs[i]);
}
free(refspecs);
}
strbuf_release(&buf);
if (debug)
fprintf(stderr, "Debug: Capabilities complete.\n");
return data->helper;
}
static int disconnect_helper(struct transport *transport)
{
struct helper_data *data = transport->data;
int res = 0;
if (data->helper) {
if (debug)
fprintf(stderr, "Debug: Disconnecting.\n");
if (!data->no_disconnect_req) {
/*
* Ignore write errors; there's nothing we can do,
* since we're about to close the pipe anyway. And the
* most likely error is EPIPE due to the helper dying
* to report an error itself.
*/
sigchain_push(SIGPIPE, SIG_IGN);
xwrite(data->helper->in, "\n", 1);
sigchain_pop(SIGPIPE);
}
close(data->helper->in);
close(data->helper->out);
fclose(data->out);
res = finish_command(data->helper);
free((char *)data->helper->argv[0]);
free(data->helper->argv);
free(data->helper);
data->helper = NULL;
}
return res;
}
static const char *unsupported_options[] = {
TRANS_OPT_UPLOADPACK,
TRANS_OPT_RECEIVEPACK,
TRANS_OPT_THIN,
TRANS_OPT_KEEP
};
static const char *boolean_options[] = {
TRANS_OPT_THIN,
TRANS_OPT_KEEP,
TRANS_OPT_FOLLOWTAGS
};
static int set_helper_option(struct transport *transport,
const char *name, const char *value)
{
struct helper_data *data = transport->data;
struct strbuf buf = STRBUF_INIT;
int i, ret, is_bool = 0;
get_helper(transport);
if (!data->option)
return 1;
for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
if (!strcmp(name, unsupported_options[i]))
return 1;
}
for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
if (!strcmp(name, boolean_options[i])) {
is_bool = 1;
break;
}
}
strbuf_addf(&buf, "option %s ", name);
if (is_bool)
strbuf_addstr(&buf, value ? "true" : "false");
else
quote_c_style(value, &buf, NULL, 0);
strbuf_addch(&buf, '\n');
xchgline(data, &buf);
if (!strcmp(buf.buf, "ok"))
ret = 0;
else if (!prefixcmp(buf.buf, "error")) {
ret = -1;
} else if (!strcmp(buf.buf, "unsupported"))
ret = 1;
else {
warning("%s unexpectedly said: '%s'", data->name, buf.buf);
ret = 1;
}
strbuf_release(&buf);
return ret;
}
static void standard_options(struct transport *t)
{
char buf[16];
int n;
int v = t->verbose;
set_helper_option(t, "progress", t->progress ? "true" : "false");
n = snprintf(buf, sizeof(buf), "%d", v + 1);
if (n >= sizeof(buf))
die("impossibly large verbosity value");
set_helper_option(t, "verbosity", buf);
}
static int release_helper(struct transport *transport)
{
int res = 0;
struct helper_data *data = transport->data;
free_refspec(data->refspec_nr, data->refspecs);
data->refspecs = NULL;
res = disconnect_helper(transport);
free(transport->data);
return res;
}
static int fetch_with_fetch(struct transport *transport,
int nr_heads, struct ref **to_fetch)
{
struct helper_data *data = transport->data;
int i;
struct strbuf buf = STRBUF_INIT;
standard_options(transport);
for (i = 0; i < nr_heads; i++) {
const struct ref *posn = to_fetch[i];
if (posn->status & REF_STATUS_UPTODATE)
continue;
strbuf_addf(&buf, "fetch %s %s\n",
sha1_to_hex(posn->old_sha1), posn->name);
}
strbuf_addch(&buf, '\n');
sendline(data, &buf);
while (1) {
recvline(data, &buf);
if (!prefixcmp(buf.buf, "lock ")) {
const char *name = buf.buf + 5;
if (transport->pack_lockfile)
warning("%s also locked %s", data->name, name);
else
transport->pack_lockfile = xstrdup(name);
}
else if (!buf.len)
break;
else
warning("%s unexpectedly said: '%s'", data->name, buf.buf);
}
strbuf_release(&buf);
return 0;
}
static int get_importer(struct transport *transport, struct child_process *fastimport)
{
struct child_process *helper = get_helper(transport);
memset(fastimport, 0, sizeof(*fastimport));
fastimport->in = helper->out;
fastimport->argv = xcalloc(5, sizeof(*fastimport->argv));
fastimport->argv[0] = "fast-import";
fastimport->argv[1] = "--quiet";
fastimport->git_cmd = 1;
return start_command(fastimport);
}
static int get_exporter(struct transport *transport,
struct child_process *fastexport,
struct string_list *revlist_args)
{
struct helper_data *data = transport->data;
struct child_process *helper = get_helper(transport);
int argc = 0, i;
memset(fastexport, 0, sizeof(*fastexport));
/* we need to duplicate helper->in because we want to use it after
* fastexport is done with it. */
fastexport->out = dup(helper->in);
fastexport->argv = xcalloc(5 + revlist_args->nr, sizeof(*fastexport->argv));
fastexport->argv[argc++] = "fast-export";
fastexport->argv[argc++] = "--use-done-feature";
if (data->export_marks)
fastexport->argv[argc++] = data->export_marks;
if (data->import_marks)
fastexport->argv[argc++] = data->import_marks;
for (i = 0; i < revlist_args->nr; i++)
fastexport->argv[argc++] = revlist_args->items[i].string;
fastexport->git_cmd = 1;
return start_command(fastexport);
}
static int fetch_with_import(struct transport *transport,
int nr_heads, struct ref **to_fetch)
{
struct child_process fastimport;
struct helper_data *data = transport->data;
int i;
struct ref *posn;
struct strbuf buf = STRBUF_INIT;
get_helper(transport);
if (get_importer(transport, &fastimport))
die("Couldn't run fast-import");
for (i = 0; i < nr_heads; i++) {
posn = to_fetch[i];
if (posn->status & REF_STATUS_UPTODATE)
continue;
strbuf_addf(&buf, "import %s\n", posn->name);
sendline(data, &buf);
strbuf_reset(&buf);
}
write_constant(data->helper->in, "\n");
if (finish_command(&fastimport))
die("Error while running fast-import");
free(fastimport.argv);
fastimport.argv = NULL;
/*
* The fast-import stream of a remote helper that advertises
* the "refspec" capability writes to the refs named after the
* right hand side of the first refspec matching each ref we
* were fetching.
*
* (If no "refspec" capability was specified, for historical
* reasons we default to *:*.)
*
* Store the result in to_fetch[i].old_sha1. Callers such
* as "git fetch" can use the value to write feedback to the
* terminal, populate FETCH_HEAD, and determine what new value
* should be written to peer_ref if the update is a
* fast-forward or this is a forced update.
*/
for (i = 0; i < nr_heads; i++) {
char *private;
posn = to_fetch[i];
if (posn->status & REF_STATUS_UPTODATE)
continue;
if (data->refspecs)
private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
else
private = xstrdup(posn->name);
if (private) {
read_ref(private, posn->old_sha1);
free(private);
}
}
strbuf_release(&buf);
return 0;
}
static int process_connect_service(struct transport *transport,
const char *name, const char *exec)
{
struct helper_data *data = transport->data;
struct strbuf cmdbuf = STRBUF_INIT;
struct child_process *helper;
int r, duped, ret = 0;
FILE *input;
helper = get_helper(transport);
/*
* Yes, dup the pipe another time, as we need unbuffered version
* of input pipe as FILE*. fclose() closes the underlying fd and
* stream buffering only can be changed before first I/O operation
* on it.
*/
duped = dup(helper->out);
if (duped < 0)
die_errno("Can't dup helper output fd");
input = xfdopen(duped, "r");
setvbuf(input, NULL, _IONBF, 0);
/*
* Handle --upload-pack and friends. This is fire and forget...
* just warn if it fails.
*/
if (strcmp(name, exec)) {
r = set_helper_option(transport, "servpath", exec);
if (r > 0)
warning("Setting remote service path not supported by protocol.");
else if (r < 0)
warning("Invalid remote service path.");
}
if (data->connect)
strbuf_addf(&cmdbuf, "connect %s\n", name);
else
goto exit;
sendline(data, &cmdbuf);
recvline_fh(input, &cmdbuf);
if (!strcmp(cmdbuf.buf, "")) {
data->no_disconnect_req = 1;
if (debug)
fprintf(stderr, "Debug: Smart transport connection "
"ready.\n");
ret = 1;
} else if (!strcmp(cmdbuf.buf, "fallback")) {
if (debug)
fprintf(stderr, "Debug: Falling back to dumb "
"transport.\n");
} else
die("Unknown response to connect: %s",
cmdbuf.buf);
exit:
fclose(input);
return ret;
}
static int process_connect(struct transport *transport,
int for_push)
{
struct helper_data *data = transport->data;
const char *name;
const char *exec;
name = for_push ? "git-receive-pack" : "git-upload-pack";
if (for_push)
exec = data->transport_options.receivepack;
else
exec = data->transport_options.uploadpack;
return process_connect_service(transport, name, exec);
}
static int connect_helper(struct transport *transport, const char *name,
const char *exec, int fd[2])
{
struct helper_data *data = transport->data;
/* Get_helper so connect is inited. */
get_helper(transport);
if (!data->connect)
die("Operation not supported by protocol.");
if (!process_connect_service(transport, name, exec))
die("Can't connect to subservice %s.", name);
fd[0] = data->helper->out;
fd[1] = data->helper->in;
return 0;
}
static int fetch(struct transport *transport,
int nr_heads, struct ref **to_fetch)
{
struct helper_data *data = transport->data;
int i, count;
if (process_connect(transport, 0)) {
do_take_over(transport);
return transport->fetch(transport, nr_heads, to_fetch);
}
count = 0;
for (i = 0; i < nr_heads; i++)
if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
count++;
if (!count)
return 0;
if (data->fetch)
return fetch_with_fetch(transport, nr_heads, to_fetch);
if (data->import)
return fetch_with_import(transport, nr_heads, to_fetch);
return -1;
}
static void push_update_ref_status(struct strbuf *buf,
struct ref **ref,
struct ref *remote_refs)
{
char *refname, *msg;
int status;
if (!prefixcmp(buf->buf, "ok ")) {
status = REF_STATUS_OK;
refname = buf->buf + 3;
} else if (!prefixcmp(buf->buf, "error ")) {
status = REF_STATUS_REMOTE_REJECT;
refname = buf->buf + 6;
} else
die("expected ok/error, helper said '%s'", buf->buf);
msg = strchr(refname, ' ');
if (msg) {
struct strbuf msg_buf = STRBUF_INIT;
const char *end;
*msg++ = '\0';
if (!unquote_c_style(&msg_buf, msg, &end))
msg = strbuf_detach(&msg_buf, NULL);
else
msg = xstrdup(msg);
strbuf_release(&msg_buf);
if (!strcmp(msg, "no match")) {
status = REF_STATUS_NONE;
free(msg);
msg = NULL;
}
else if (!strcmp(msg, "up to date")) {
status = REF_STATUS_UPTODATE;
free(msg);
msg = NULL;
}
else if (!strcmp(msg, "non-fast forward")) {
status = REF_STATUS_REJECT_NONFASTFORWARD;
free(msg);
msg = NULL;
}
}
if (*ref)
*ref = find_ref_by_name(*ref, refname);
if (!*ref)
*ref = find_ref_by_name(remote_refs, refname);
if (!*ref) {
warning("helper reported unexpected status of %s", refname);
return;
}
if ((*ref)->status != REF_STATUS_NONE) {
/*
* Earlier, the ref was marked not to be pushed, so ignore the ref
* status reported by the remote helper if the latter is 'no match'.
*/
if (status == REF_STATUS_NONE)
return;
}
(*ref)->status = status;
(*ref)->remote_status = msg;
}
static void push_update_refs_status(struct helper_data *data,
struct ref *remote_refs)
{
struct strbuf buf = STRBUF_INIT;
struct ref *ref = remote_refs;
for (;;) {
recvline(data, &buf);
if (!buf.len)
break;
push_update_ref_status(&buf, &ref, remote_refs);
}
strbuf_release(&buf);
}
static int push_refs_with_push(struct transport *transport,
struct ref *remote_refs, int flags)
{
int force_all = flags & TRANSPORT_PUSH_FORCE;
int mirror = flags & TRANSPORT_PUSH_MIRROR;
struct helper_data *data = transport->data;
struct strbuf buf = STRBUF_INIT;
struct ref *ref;
get_helper(transport);
if (!data->push)
return 1;
for (ref = remote_refs; ref; ref = ref->next) {
if (!ref->peer_ref && !mirror)
continue;
/* Check for statuses set by set_ref_status_for_push() */
switch (ref->status) {
case REF_STATUS_REJECT_NONFASTFORWARD:
case REF_STATUS_UPTODATE:
continue;
default:
; /* do nothing */
}
if (force_all)
ref->force = 1;
strbuf_addstr(&buf, "push ");
if (!ref->deletion) {
if (ref->force)
strbuf_addch(&buf, '+');
if (ref->peer_ref)
strbuf_addstr(&buf, ref->peer_ref->name);
else
strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
}
strbuf_addch(&buf, ':');
strbuf_addstr(&buf, ref->name);
strbuf_addch(&buf, '\n');
}
if (buf.len == 0)
return 0;
standard_options(transport);
if (flags & TRANSPORT_PUSH_DRY_RUN) {
if (set_helper_option(transport, "dry-run", "true") != 0)
die("helper %s does not support dry-run", data->name);
}
strbuf_addch(&buf, '\n');
sendline(data, &buf);
strbuf_release(&buf);
push_update_refs_status(data, remote_refs);
return 0;
}
static int push_refs_with_export(struct transport *transport,
struct ref *remote_refs, int flags)
{
struct ref *ref;
struct child_process *helper, exporter;
struct helper_data *data = transport->data;
struct string_list revlist_args = STRING_LIST_INIT_NODUP;
struct strbuf buf = STRBUF_INIT;
helper = get_helper(transport);
write_constant(helper->in, "export\n");
strbuf_reset(&buf);
for (ref = remote_refs; ref; ref = ref->next) {
char *private;
unsigned char sha1[20];
if (!data->refspecs)
continue;
private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
if (private && !get_sha1(private, sha1)) {
strbuf_addf(&buf, "^%s", private);
string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
}
free(private);
if (ref->deletion) {
die("remote-helpers do not support ref deletion");
}
if (ref->peer_ref)
string_list_append(&revlist_args, ref->peer_ref->name);
}
if (get_exporter(transport, &exporter, &revlist_args))
die("Couldn't run fast-export");
if (finish_command(&exporter))
die("Error while running fast-export");
push_update_refs_status(data, remote_refs);
return 0;
}
static int push_refs(struct transport *transport,
struct ref *remote_refs, int flags)
{
struct helper_data *data = transport->data;
if (process_connect(transport, 1)) {
do_take_over(transport);
return transport->push_refs(transport, remote_refs, flags);
}
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;
}
if (data->push)
return push_refs_with_push(transport, remote_refs, flags);
if (data->export)
return push_refs_with_export(transport, remote_refs, flags);
return -1;
}
static int has_attribute(const char *attrs, const char *attr) {
int len;
if (!attrs)
return 0;
len = strlen(attr);
for (;;) {
const char *space = strchrnul(attrs, ' ');
if (len == space - attrs && !strncmp(attrs, attr, len))
return 1;
if (!*space)
return 0;
attrs = space + 1;
}
}
static struct ref *get_refs_list(struct transport *transport, int for_push)
{
struct helper_data *data = transport->data;
struct child_process *helper;
struct ref *ret = NULL;
struct ref **tail = &ret;
struct ref *posn;
struct strbuf buf = STRBUF_INIT;
helper = get_helper(transport);
if (process_connect(transport, for_push)) {
do_take_over(transport);
return transport->get_refs_list(transport, for_push);
}
if (data->push && for_push)
write_str_in_full(helper->in, "list for-push\n");
else
write_str_in_full(helper->in, "list\n");
while (1) {
char *eov, *eon;
recvline(data, &buf);
if (!*buf.buf)
break;
eov = strchr(buf.buf, ' ');
if (!eov)
die("Malformed response in ref list: %s", buf.buf);
eon = strchr(eov + 1, ' ');
*eov = '\0';
if (eon)
*eon = '\0';
*tail = alloc_ref(eov + 1);
if (buf.buf[0] == '@')
(*tail)->symref = xstrdup(buf.buf + 1);
else if (buf.buf[0] != '?')
get_sha1_hex(buf.buf, (*tail)->old_sha1);
if (eon) {
if (has_attribute(eon + 1, "unchanged")) {
(*tail)->status |= REF_STATUS_UPTODATE;
read_ref((*tail)->name, (*tail)->old_sha1);
}
}
tail = &((*tail)->next);
}
if (debug)
fprintf(stderr, "Debug: Read ref listing.\n");
strbuf_release(&buf);
for (posn = ret; posn; posn = posn->next)
resolve_remote_symref(posn, ret);
return ret;
}
int transport_helper_init(struct transport *transport, const char *name)
{
struct helper_data *data = xcalloc(sizeof(*data), 1);
data->name = name;
if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
debug = 1;
transport->data = data;
transport->set_option = set_helper_option;
transport->get_refs_list = get_refs_list;
transport->fetch = fetch;
transport->push_refs = push_refs;
transport->disconnect = release_helper;
transport->connect = connect_helper;
transport->smart_options = &(data->transport_options);
return 0;
}
/*
* Linux pipes can buffer 65536 bytes at once (and most platforms can
* buffer less), so attempt reads and writes with up to that size.
*/
#define BUFFERSIZE 65536
/* This should be enough to hold debugging message. */
#define PBUFFERSIZE 8192
/* Print bidirectional transfer loop debug message. */
static void transfer_debug(const char *fmt, ...)
{
va_list args;
char msgbuf[PBUFFERSIZE];
static int debug_enabled = -1;
if (debug_enabled < 0)
debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
if (!debug_enabled)
return;
va_start(args, fmt);
vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
va_end(args);
fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
}
/* Stream state: More data may be coming in this direction. */
#define SSTATE_TRANSFERING 0
/*
* Stream state: No more data coming in this direction, flushing rest of
* data.
*/
#define SSTATE_FLUSHING 1
/* Stream state: Transfer in this direction finished. */
#define SSTATE_FINISHED 2
#define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
#define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
#define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
/* Unidirectional transfer. */
struct unidirectional_transfer {
/* Source */
int src;
/* Destination */
int dest;
/* Is source socket? */
int src_is_sock;
/* Is destination socket? */
int dest_is_sock;
/* Transfer state (TRANSFERING/FLUSHING/FINISHED) */
int state;
/* Buffer. */
char buf[BUFFERSIZE];
/* Buffer used. */
size_t bufuse;
/* Name of source. */
const char *src_name;
/* Name of destination. */
const char *dest_name;
};
/* Closes the target (for writing) if transfer has finished. */
static void udt_close_if_finished(struct unidirectional_transfer *t)
{
if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
t->state = SSTATE_FINISHED;
if (t->dest_is_sock)
shutdown(t->dest, SHUT_WR);
else
close(t->dest);
transfer_debug("Closed %s.", t->dest_name);
}
}
/*
* Tries to read read data from source into buffer. If buffer is full,
* no data is read. Returns 0 on success, -1 on error.
*/
static int udt_do_read(struct unidirectional_transfer *t)
{
ssize_t bytes;
if (t->bufuse == BUFFERSIZE)
return 0; /* No space for more. */
transfer_debug("%s is readable", t->src_name);
bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
errno != EINTR) {
error("read(%s) failed: %s", t->src_name, strerror(errno));
return -1;
} else if (bytes == 0) {
transfer_debug("%s EOF (with %i bytes in buffer)",
t->src_name, t->bufuse);
t->state = SSTATE_FLUSHING;
} else if (bytes > 0) {
t->bufuse += bytes;
transfer_debug("Read %i bytes from %s (buffer now at %i)",
(int)bytes, t->src_name, (int)t->bufuse);
}
return 0;
}
/* Tries to write data from buffer into destination. If buffer is empty,
* no data is written. Returns 0 on success, -1 on error.
*/
static int udt_do_write(struct unidirectional_transfer *t)
{
ssize_t bytes;
if (t->bufuse == 0)
return 0; /* Nothing to write. */
transfer_debug("%s is writable", t->dest_name);
bytes = write(t->dest, t->buf, t->bufuse);
if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
errno != EINTR) {
error("write(%s) failed: %s", t->dest_name, strerror(errno));
return -1;
} else if (bytes > 0) {
t->bufuse -= bytes;
if (t->bufuse)
memmove(t->buf, t->buf + bytes, t->bufuse);
transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
(int)bytes, t->dest_name, (int)t->bufuse);
}
return 0;
}
/* State of bidirectional transfer loop. */
struct bidirectional_transfer_state {
/* Direction from program to git. */
struct unidirectional_transfer ptg;
/* Direction from git to program. */
struct unidirectional_transfer gtp;
};
static void *udt_copy_task_routine(void *udt)
{
struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
while (t->state != SSTATE_FINISHED) {
if (STATE_NEEDS_READING(t->state))
if (udt_do_read(t))
return NULL;
if (STATE_NEEDS_WRITING(t->state))
if (udt_do_write(t))
return NULL;
if (STATE_NEEDS_CLOSING(t->state))
udt_close_if_finished(t);
}
return udt; /* Just some non-NULL value. */
}
#ifndef NO_PTHREADS
/*
* Join thread, with apporiate errors on failure. Name is name for the
* thread (for error messages). Returns 0 on success, 1 on failure.
*/
static int tloop_join(pthread_t thread, const char *name)
{
int err;
void *tret;
err = pthread_join(thread, &tret);
if (!tret) {
error("%s thread failed", name);
return 1;
}
if (err) {
error("%s thread failed to join: %s", name, strerror(err));
return 1;
}
return 0;
}
/*
* Spawn the transfer tasks and then wait for them. Returns 0 on success,
* -1 on failure.
*/
static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
{
pthread_t gtp_thread;
pthread_t ptg_thread;
int err;
int ret = 0;
err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
&s->gtp);
if (err)
die("Can't start thread for copying data: %s", strerror(err));
err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
&s->ptg);
if (err)
die("Can't start thread for copying data: %s", strerror(err));
ret |= tloop_join(gtp_thread, "Git to program copy");
ret |= tloop_join(ptg_thread, "Program to git copy");
return ret;
}
#else
/* Close the source and target (for writing) for transfer. */
static void udt_kill_transfer(struct unidirectional_transfer *t)
{
t->state = SSTATE_FINISHED;
/*
* Socket read end left open isn't a disaster if nobody
* attempts to read from it (mingw compat headers do not
* have SHUT_RD)...
*
* We can't fully close the socket since otherwise gtp
* task would first close the socket it sends data to
* while closing the ptg file descriptors.
*/
if (!t->src_is_sock)
close(t->src);
if (t->dest_is_sock)
shutdown(t->dest, SHUT_WR);
else
close(t->dest);
}
/*
* Join process, with apporiate errors on failure. Name is name for the
* process (for error messages). Returns 0 on success, 1 on failure.
*/
static int tloop_join(pid_t pid, const char *name)
{
int tret;
if (waitpid(pid, &tret, 0) < 0) {
error("%s process failed to wait: %s", name, strerror(errno));
return 1;
}
if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
error("%s process failed", name);
return 1;
}
return 0;
}
/*
* Spawn the transfer tasks and then wait for them. Returns 0 on success,
* -1 on failure.
*/
static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
{
pid_t pid1, pid2;
int ret = 0;
/* Fork thread #1: git to program. */
pid1 = fork();
if (pid1 < 0)
die_errno("Can't start thread for copying data");
else if (pid1 == 0) {
udt_kill_transfer(&s->ptg);
exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
}
/* Fork thread #2: program to git. */
pid2 = fork();
if (pid2 < 0)
die_errno("Can't start thread for copying data");
else if (pid2 == 0) {
udt_kill_transfer(&s->gtp);
exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
}
/*
* Close both streams in parent as to not interfere with
* end of file detection and wait for both tasks to finish.
*/
udt_kill_transfer(&s->gtp);
udt_kill_transfer(&s->ptg);
ret |= tloop_join(pid1, "Git to program copy");
ret |= tloop_join(pid2, "Program to git copy");
return ret;
}
#endif
/*
* Copies data from stdin to output and from input to stdout simultaneously.
* Additionally filtering through given filter. If filter is NULL, uses
* identity filter.
*/
int bidirectional_transfer_loop(int input, int output)
{
struct bidirectional_transfer_state state;
/* Fill the state fields. */
state.ptg.src = input;
state.ptg.dest = 1;
state.ptg.src_is_sock = (input == output);
state.ptg.dest_is_sock = 0;
state.ptg.state = SSTATE_TRANSFERING;
state.ptg.bufuse = 0;
state.ptg.src_name = "remote input";
state.ptg.dest_name = "stdout";
state.gtp.src = 0;
state.gtp.dest = output;
state.gtp.src_is_sock = 0;
state.gtp.dest_is_sock = (input == output);
state.gtp.state = SSTATE_TRANSFERING;
state.gtp.bufuse = 0;
state.gtp.src_name = "stdin";
state.gtp.dest_name = "remote output";
return tloop_spawnwait_tasks(&state);
}
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