static size_t
channel_wanted_readsz(struct channel* c)
{
if (c->dir != CHANNEL_FROM_FD)
return 0;
if (c->fdh == NULL)
return 0;
return XMIN(ringbuf_room(c->rb), c->window);
}
void
dbgch(const char* label, struct channel** ch, unsigned nrch)
{
SCOPED_RESLIST(rl_dbgch);
unsigned chno;
dbglock();
dbg("DBGCH[%s]", label);
for (chno = 0; chno < nrch; ++chno) {
struct channel* c = ch[chno];
struct pollfd p = channel_request_poll(ch[chno]);
const char* pev;
switch (p.events) {
case POLLIN | POLLOUT:
pev = "POLLIN,POLLOUT";
break;
case POLLIN:
pev = "POLLIN";
break;
case POLLOUT:
pev = "POLLOUT";
break;
case 0:
pev = "NONE";
break;
default:
pev = xaprintf("%xd", p.events);
break;
}
assert(p.fd == -1 || p.fd == c->fdh->fd);
dbg(" %-18s size:%-4zu room:%-4zu window:%-4d %s%-2s %p %s",
xaprintf("ch[%d=%s]", chno, chname(chno)),
ringbuf_size(c->rb),
ringbuf_room(c->rb),
c->window,
(c->dir == CHANNEL_FROM_FD ? "<" : ">"),
((c->fdh != NULL)
? xaprintf("%d", c->fdh->fd)
: (c->sent_eof ? "!!" : "!?")),
c,
pev);
}
}
static struct child*
start_child(struct msg_shex_hello* shex_hello)
{
if (shex_hello->nr_argv < 2)
die(ECOMM, "insufficient arguments given");
SCOPED_RESLIST(rl_args);
char** child_args = read_child_arglist(shex_hello->nr_argv);
reslist_pop_nodestroy(rl_args);
struct child_start_info csi = {
.flags = CHILD_SETSID,
.exename = child_args[0],
.argv = (const char* const *) child_args + 1,
.pty_setup = setup_pty,
.pty_setup_data = shex_hello,
.deathsig = -SIGHUP,
};
if (shex_hello->si[0].pty_p)
csi.flags |= CHILD_PTY_STDIN;
if (shex_hello->si[1].pty_p)
csi.flags |= CHILD_PTY_STDOUT;
if (shex_hello->si[2].pty_p)
csi.flags |= CHILD_PTY_STDERR;
return child_start(&csi);
}
static void __attribute__((noreturn))
re_exec_as_root()
{
execlp("su", "su", "-c", xaprintf("%s stub", orig_argv0), NULL);
die_errno("execlp of su");
}
int
stub_main(int argc, const char** argv)
{
if (argc != 1)
die(EINVAL, "this command is internal");
/* XMKRAW_SKIP_CLEANUP so we never change from raw back to cooked
* mode on exit. The connection dies on exit anyway, and
* resetting the pty can send some extra bytes that can confuse
* our peer. */
if (isatty(0))
xmkraw(0, XMKRAW_SKIP_CLEANUP);
if (isatty(1))
xmkraw(1, XMKRAW_SKIP_CLEANUP);
printf(FB_ADB_PROTO_START_LINE "\n", build_time, (int) getuid());
fflush(stdout);
struct msg_shex_hello* shex_hello;
struct msg* mhdr = read_msg(0, read_all_adb_encoded);
if (mhdr->type == MSG_EXEC_AS_ROOT)
re_exec_as_root(); // Never returns
if (mhdr->type != MSG_SHEX_HELLO ||
mhdr->size < sizeof (struct msg_shex_hello))
{
die(ECOMM, "bad hello");
}
shex_hello = (struct msg_shex_hello*) mhdr;
struct child* child = start_child(shex_hello);
struct stub stub;
memset(&stub, 0, sizeof (stub));
stub.child = child;
struct fb_adb_sh* sh = &stub.sh;
sh->process_msg = stub_process_msg;
sh->max_outgoing_msg = shex_hello->maxmsg;
sh->nrch = 5;
struct channel** ch = xalloc(sh->nrch * sizeof (*ch));
ch[FROM_PEER] = channel_new(fdh_dup(0),
shex_hello->stub_recv_bufsz,
CHANNEL_FROM_FD);
ch[FROM_PEER]->window = UINT32_MAX;
ch[FROM_PEER]->adb_encoding_hack = true;
replace_with_dev_null(0);
ch[TO_PEER] = channel_new(fdh_dup(1),
shex_hello->stub_send_bufsz,
CHANNEL_TO_FD);
replace_with_dev_null(1);
ch[CHILD_STDIN] = channel_new(child->fd[0],
shex_hello->si[0].bufsz,
CHANNEL_TO_FD);
ch[CHILD_STDIN]->track_bytes_written = true;
ch[CHILD_STDIN]->bytes_written =
ringbuf_room(ch[CHILD_STDIN]->rb);
ch[CHILD_STDOUT] = channel_new(child->fd[1],
shex_hello->si[1].bufsz,
CHANNEL_FROM_FD);
ch[CHILD_STDOUT]->track_window = true;
ch[CHILD_STDERR] = channel_new(child->fd[2],
shex_hello->si[2].bufsz,
CHANNEL_FROM_FD);
ch[CHILD_STDERR]->track_window = true;
sh->ch = ch;
io_loop_init(sh);
PUMP_WHILE(sh, (!channel_dead_p(ch[FROM_PEER]) &&
!channel_dead_p(ch[TO_PEER]) &&
(!channel_dead_p(ch[CHILD_STDOUT]) ||
!channel_dead_p(ch[CHILD_STDERR]))));
if (channel_dead_p(ch[FROM_PEER]) || channel_dead_p(ch[TO_PEER])) {
//
// If we lost our peer connection, make sure the child sees
// SIGHUP instead of seeing its stdin close: just drain any
// internally-buffered IO and exit. When we lose the pty, the
// child gets SIGHUP.
//
// Make sure we won't be getting any more commands.
channel_close(ch[FROM_PEER]);
channel_close(ch[TO_PEER]);
PUMP_WHILE(sh, (!channel_dead_p(ch[FROM_PEER]) ||
!channel_dead_p(ch[TO_PEER])));
// Drain output buffers
channel_close(ch[CHILD_STDIN]);
PUMP_WHILE(sh, !channel_dead_p(ch[CHILD_STDIN]));
return 128 + SIGHUP;
}
//
// Clean exit: close standard handles and drain IO. Peer still
// has no idea that we're exiting. Get exit status, send that to
// peer, then cleanly shut down the peer connection.
//
dbg("clean exit");
channel_close(ch[CHILD_STDIN]);
channel_close(ch[CHILD_STDOUT]);
channel_close(ch[CHILD_STDERR]);
PUMP_WHILE (sh, (!channel_dead_p(ch[CHILD_STDIN]) ||
!channel_dead_p(ch[CHILD_STDOUT]) ||
!channel_dead_p(ch[CHILD_STDERR])));
send_exit_message(child_wait(child), sh);
channel_close(ch[TO_PEER]);
PUMP_WHILE(sh, !channel_dead_p(ch[TO_PEER]));
channel_close(ch[FROM_PEER]);
PUMP_WHILE(sh, !channel_dead_p(ch[FROM_PEER]));
return 0;
}
