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authorLukas Larsson <[email protected]>2014-06-26 18:55:47 +0200
committerLukas Larsson <[email protected]>2014-10-16 17:56:16 +0200
commit48083e54b502afb2768066394074d29423162dc8 (patch)
tree00edbcd4e486ac47a61a701d3f0cc6f2e3004156 /erts/emulator/drivers/unix/ttsl_drv.c
parent5ab275d6554f4db877624a152dda90c0e3c4cddc (diff)
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kernel,ssh: Add synchronous user_drv protocol
Added a put_chars_sync to the protocol that can be used to talk to user_drv and made group use it. This is needed in order to guarantee that bytes has been pushed to the tty port when doing something like this: io:format("halting\n"),erlang:halt(0). Before this change the halting message could be lost in the message queue of the user_drv process, this is no longer possible. This commit also fixes ssh_cli as that plugs itself in as a user_drv process. OTP-12240
Diffstat (limited to 'erts/emulator/drivers/unix/ttsl_drv.c')
-rw-r--r--erts/emulator/drivers/unix/ttsl_drv.c36
1 files changed, 36 insertions, 0 deletions
diff --git a/erts/emulator/drivers/unix/ttsl_drv.c b/erts/emulator/drivers/unix/ttsl_drv.c
index 73ce27c6ec..be2fee1f25 100644
--- a/erts/emulator/drivers/unix/ttsl_drv.c
+++ b/erts/emulator/drivers/unix/ttsl_drv.c
@@ -93,6 +93,7 @@ static volatile int cols_needs_update = FALSE;
#define OP_INSC 2
#define OP_DELC 3
#define OP_BEEP 4
+#define OP_PUTC_SYNC 5
/* Control op */
#define CTRL_OP_GET_WINSIZE 100
#define CTRL_OP_GET_UNICODE_STATE 101
@@ -137,6 +138,7 @@ static Sint16 get_sint16(char*);
static ErlDrvPort ttysl_port;
static int ttysl_fd;
static int ttysl_terminate = 0;
+static int ttysl_send_ok = 0;
static ErlDrvBinary *putcbuf;
static int putcpos;
static int putclen;
@@ -683,6 +685,14 @@ static void ttysl_from_erlang(ErlDrvData ttysl_data, char* buf, ErlDrvSizeT coun
put_chars((byte*)"\n", 1);
switch (buf[0]) {
+ case OP_PUTC_SYNC:
+ /* Using sync means that we have to send an ok to the
+ controlling process for each command call. We delay
+ sending ok if the driver queue exceeds a certain size.
+ We do not set ourselves as a busy port, as this
+ could be very bad for user_drv, if it gets blocked on
+ the port_command. */
+ /* fall through */
case OP_PUTC:
DEBUGLOG(("OP: Putc(%lu)",(unsigned long) count-1));
if (check_buf_size((byte*)buf+1, count-1) == 0)
@@ -736,6 +746,22 @@ static void ttysl_from_erlang(ErlDrvData ttysl_data, char* buf, ErlDrvSizeT coun
}
}
+ if (buf[0] == OP_PUTC_SYNC) {
+ if (driver_sizeq(ttysl_port) > TTY_BUFFSIZE && !ttysl_terminate) {
+ /* We delay sending the ack until the buffer has been consumed */
+ ttysl_send_ok = 1;
+ } else {
+ ErlDrvTermData spec[] = {
+ ERL_DRV_PORT, driver_mk_port(ttysl_port),
+ ERL_DRV_ATOM, driver_mk_atom("ok"),
+ ERL_DRV_TUPLE, 2
+ };
+ ASSERT(ttysl_send_ok == 0);
+ erl_drv_output_term(driver_mk_port(ttysl_port), spec,
+ sizeof(spec) / sizeof(spec[0]));
+ }
+ }
+
return; /* TRUE; */
}
@@ -758,6 +784,16 @@ static void ttysl_to_tty(ErlDrvData ttysl_data, ErlDrvEvent fd) {
}
} else {
sz = driver_deq(ttysl_port, written);
+ if (sz < TTY_BUFFSIZE && ttysl_send_ok) {
+ ErlDrvTermData spec[] = {
+ ERL_DRV_PORT, driver_mk_port(ttysl_port),
+ ERL_DRV_ATOM, driver_mk_atom("ok"),
+ ERL_DRV_TUPLE, 2
+ };
+ ttysl_send_ok = 0;
+ erl_drv_output_term(driver_mk_port(ttysl_port), spec,
+ sizeof(spec) / sizeof(spec[0]));
+ }
if (sz == 0) {
driver_select(ttysl_port,(ErlDrvEvent)(long)ttysl_fd,
ERL_DRV_WRITE,0);