New forkoff() and chan_wont_read/write() API
Nicolas Williams
Nicolas.Williams at ubsw.com
Wed Feb 6 03:26:08 EST 2002
Markus,
How's this patch?
- a chan_wont_read()/chan_wont_write() API is added that is very much
like chan_read_failed()/chan_write_failed(), but for the debug
messages and chan_wont_*() don't ever call error()
The 3.0.2p1 channel_pre_x11_open() uses chan_*_failed() but looks
like it ought to use chan_wont_*() instead :)
- forkoff() no longer fakes EOF for SSHv2 (still does for SSHv1 - dunno
what to do there)
- the session channel lookup, chan_wont_*(), chan_close_fds(), detach
bit is only done for SSHv2
Nico
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-------------- next part --------------
Index: 3_0_2p1.1/nchan.c
--- 3_0_2p1.1/nchan.c Wed, 21 Nov 2001 10:38:46 -0500 jd (OpenSSH/i/40_nchan.c 1.1.1.1 644)
+++ 3_0_2p1_w_gssk5_ubsw_experimental.6/nchan.c Tue, 05 Feb 2002 11:25:25 -0500 willian (OpenSSH/i/40_nchan.c 1.1.1.4 644)
@@ -66,10 +66,12 @@
/* events concerning the INPUT from socket for channel (istate) */
chan_event_fn *chan_rcvd_oclose = NULL;
chan_event_fn *chan_read_failed = NULL;
+chan_event_fn *chan_wont_read = NULL;
chan_event_fn *chan_ibuf_empty = NULL;
/* events concerning the OUTPUT from channel for socket (ostate) */
chan_event_fn *chan_rcvd_ieof = NULL;
chan_event_fn *chan_write_failed = NULL;
+chan_event_fn *chan_wont_write = NULL;
chan_event_fn *chan_obuf_empty = NULL;
/*
* ACTIONS: should never update the channel states
@@ -137,6 +139,28 @@
}
}
static void
+chan_wont_read_12(Channel *c)
+{
+ debug("channel %d: wont read", c->self);
+ switch (c->istate) {
+ case CHAN_INPUT_OPEN:
+ debug("channel %d: input open -> drain", c->self);
+ chan_shutdown_read(c);
+ c->istate = CHAN_INPUT_WAIT_DRAIN;
+#if 0
+ if (buffer_len(&c->input) == 0) {
+ debug("channel %d: input: no drain shortcut", c->self);
+ chan_ibuf_empty(c);
+ }
+#endif
+ break;
+ default:
+ debug("channel %d: chan_wont_read for istate %d",
+ c->self, c->istate);
+ break;
+ }
+}
+static void
chan_ibuf_empty1(Channel *c)
{
debug("channel %d: ibuf empty", c->self);
@@ -221,6 +245,27 @@
}
}
static void
+chan_wont_write1(Channel *c)
+{
+ debug("channel %d: wont write", c->self);
+ switch (c->ostate) {
+ case CHAN_OUTPUT_OPEN:
+ debug("channel %d: output open -> wait_ieof", c->self);
+ chan_send_oclose1(c);
+ c->ostate = CHAN_OUTPUT_WAIT_IEOF;
+ break;
+ case CHAN_OUTPUT_WAIT_DRAIN:
+ debug("channel %d: output wait_drain -> closed", c->self);
+ chan_send_oclose1(c);
+ c->ostate = CHAN_OUTPUT_CLOSED;
+ break;
+ default:
+ debug("channel %d: chan_wont_write for ostate %d",
+ c->self, c->ostate);
+ break;
+ }
+}
+static void
chan_obuf_empty1(Channel *c)
{
debug("channel %d: obuf empty", c->self);
@@ -369,6 +414,27 @@
}
}
static void
+chan_wont_write2(Channel *c)
+{
+ debug("channel %d: wont write", c->self);
+ switch (c->ostate) {
+ case CHAN_OUTPUT_OPEN:
+ debug("channel %d: output open -> closed", c->self);
+ chan_shutdown_write(c); /* ?? */
+ c->ostate = CHAN_OUTPUT_CLOSED;
+ break;
+ case CHAN_OUTPUT_WAIT_DRAIN:
+ debug("channel %d: output drain -> closed", c->self);
+ chan_shutdown_write(c);
+ c->ostate = CHAN_OUTPUT_CLOSED;
+ break;
+ default:
+ debug("channel %d: chan_wont_write for ostate %d",
+ c->self, c->ostate);
+ break;
+ }
+}
+static void
chan_obuf_empty2(Channel *c)
{
debug("channel %d: obuf empty", c->self);
@@ -496,18 +562,22 @@
if (compat20) {
chan_rcvd_oclose = chan_rcvd_oclose2;
chan_read_failed = chan_read_failed_12;
+ chan_wont_read = chan_wont_read_12;
chan_ibuf_empty = chan_ibuf_empty2;
chan_rcvd_ieof = chan_rcvd_ieof2;
chan_write_failed = chan_write_failed2;
+ chan_wont_write = chan_wont_write2;
chan_obuf_empty = chan_obuf_empty2;
} else {
chan_rcvd_oclose = chan_rcvd_oclose1;
chan_read_failed = chan_read_failed_12;
+ chan_wont_read = chan_wont_read_12;
chan_ibuf_empty = chan_ibuf_empty1;
chan_rcvd_ieof = chan_rcvd_ieof1;
chan_write_failed = chan_write_failed1;
+ chan_wont_write = chan_wont_write2;
chan_obuf_empty = chan_obuf_empty1;
}
}
Index: 3_0_2p1.1/clientloop.c
--- 3_0_2p1.1/clientloop.c Wed, 21 Nov 2001 10:38:46 -0500 jd (OpenSSH/j/41_clientloop 1.1.2.1 644)
+++ 3_0_2p1_w_gssk5_ubsw_experimental.6/clientloop.c Tue, 05 Feb 2002 11:16:16 -0500 willian (OpenSSH/j/41_clientloop 1.1.2.7 644)
@@ -1007,6 +1051,81 @@
/*********/
+/*
+ * Detach the program (continue to serve connections,
+ * but put in background and no more new connections).
+ */
+static
+void
+forkoff(int stop_listening, int detach)
+{
+ pid_t pid;
+ int fd;
+ Channel *c;
+
+ /* Restore tty modes. */
+ leave_raw_mode();
+
+ /* Stop listening for new connections. */
+ if (stop_listening)
+ channel_stop_listening();
+
+ fprintf(stderr, "Forking off into the background - %s, %s",
+ stop_listening ? "no longer listening" : "still listening",
+ detach ? "detaching" : "not detaching");
+
+ /* Fork into background. */
+ pid = fork();
+ if (pid < 0) {
+ error("fork: %.100s", strerror(errno));
+ return;
+ }
+ if (pid != 0) { /* This is the parent. */
+ /* The parent just exits. */
+ exit(0);
+ }
+
+ /* fake EOF on stdin for SSHv1 */
+ if (!compat20 && !stdin_eof) {
+ /*
+ * Sending SSH_CMSG_EOF alone does not always appear
+ * to be enough. So we try to send an EOF character
+ * first.
+ */
+ packet_start(SSH_CMSG_STDIN_DATA);
+ packet_put_string("\004", 1);
+ packet_send();
+ /* Close stdin. */
+ stdin_eof = 1;
+ if (buffer_len(&stdin_buffer) == 0) {
+ packet_start(SSH_CMSG_EOF);
+ packet_send();
+ }
+ }
+
+ if (!compat20)
+ return;
+
+ c = channel_lookup(session_ident);
+ if (c == NULL)
+ error("couldn't lookup session channel");
+
+ if (detach) {
+ chan_wont_read(c);
+ chan_wont_write(c);
+ channel_close_fds(c);
+ fd = open(_PATH_DEVNULL, O_RDWR, 0);
+ if (fd < 0)
+ return;
+ (void) dup2(fd, STDIN_FILENO);
+ (void) dup2(fd, STDOUT_FILENO);
+ (void) dup2(fd, STDERR_FILENO);
+ if (fd > 2)
+ (void) close(fd);
+ (void) setsid();
+ }
+}
+
static void
client_input_stdout_data(int type, int plen, void *ctxt)
{
Index: 3_0_2p1.1/channels.h
--- 3_0_2p1.1/channels.h Wed, 21 Nov 2001 10:38:46 -0500 jd (OpenSSH/j/46_channels.h 1.2.1.1 644)
+++ 3_0_2p1_w_gssk5_ubsw_experimental.6/channels.h Tue, 05 Feb 2002 11:04:53 -0500 willian (OpenSSH/j/46_channels.h 1.2.1.3 644)
@@ -153,6 +153,7 @@
void channel_register_filter(int, channel_filter_fn *);
void channel_cancel_cleanup(int);
int channel_close_fd(int *);
+void channel_close_fds(Channel *);
/* protocol handler */
@@ -224,11 +225,13 @@
/* for the input state */
extern chan_event_fn *chan_rcvd_oclose;
extern chan_event_fn *chan_read_failed;
+extern chan_event_fn *chan_wont_read;
extern chan_event_fn *chan_ibuf_empty;
/* for the output state */
extern chan_event_fn *chan_rcvd_ieof;
extern chan_event_fn *chan_write_failed;
+extern chan_event_fn *chan_wont_write;
extern chan_event_fn *chan_obuf_empty;
#endif
Index: 3_0_2p1.1/channels.c
--- 3_0_2p1.1/channels.c Wed, 21 Nov 2001 10:38:46 -0500 jd (OpenSSH/j/47_channels.c 1.2.2.1 644)
+++ 3_0_2p1_w_gssk5_ubsw_experimental.6/channels.c Thu, 17 Jan 2002 14:17:25 -0500 willian (OpenSSH/j/47_channels.c 1.2.2.2 644)
@@ -301,7 +301,7 @@
/* Close all channel fd/socket. */
-static void
+void
channel_close_fds(Channel *c)
{
debug3("channel_close_fds: channel %d: r %d w %d e %d",
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