aio: Add support for modem control signals

RTS, DTR, etc. and sending a break condition

Signed-off-by: Steve Bennett <steveb@workware.net.au>

4 files changed, 178 insertions, 1 deletions

diff --git a/jim-aio.c b/jim-aio.c
index 0805d41..7f1d608 100644
--- a/jim-aio.c
+++ b/jim-aio.c
@@ -1906,6 +1906,49 @@ static int aio_cmd_tty(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 
     return ret;
 }
+
+static int aio_cmd_ttycontrol(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
+{
+    AioFile *af = Jim_CmdPrivData(interp);
+    Jim_Obj *dictObjPtr;
+    int ret;
+
+    if (argc == 0) {
+        /* get the current settings as a dictionary */
+        dictObjPtr = Jim_GetTtyControlSettings(interp, af->fd);
+        if (dictObjPtr == NULL) {
+            JimAioSetError(interp, NULL);
+            return JIM_ERR;
+        }
+        Jim_SetResult(interp, dictObjPtr);
+        return JIM_OK;
+    }
+
+    if (argc > 1) {
+        /* Convert name value arguments to a dictionary */
+        dictObjPtr = Jim_NewListObj(interp, argv, argc);
+    }
+    else {
+        /* The settings are already given as a list */
+        dictObjPtr = argv[0];
+    }
+    Jim_IncrRefCount(dictObjPtr);
+
+    if (Jim_ListLength(interp, dictObjPtr) % 2) {
+        /* Must be a valid dictionary */
+        Jim_DecrRefCount(interp, dictObjPtr);
+        return -1;
+    }
+
+    ret = Jim_SetTtyControlSettings(interp, af->fd, dictObjPtr);
+    if (ret < 0) {
+        JimAioSetError(interp, NULL);
+        ret = JIM_ERR;
+    }
+    Jim_DecrRefCount(interp, dictObjPtr);
+
+    return ret;
+}
 #endif /* JIM_BOOTSTRAP */
 
 static const jim_subcmd_type aio_command_table[] = {
@@ -2151,6 +2194,13 @@ static const jim_subcmd_type aio_command_table[] = {
         -1,
         /* Description: Get or set tty settings - valid only on a tty */
     },
+    {   "ttycontrol",
+        "?rts 0|1? ?dtr 0|1?",
+        aio_cmd_ttycontrol,
+        0,
+        -1,
+        /* Description: Get or set tty modem control settings - valid only on a tty */
+    },
 #endif
 #endif /* JIM_BOOTSTRAP */
     { NULL }
diff --git a/jim-tty.c b/jim-tty.c
index 534e65c..245d3bf 100644
--- a/jim-tty.c
+++ b/jim-tty.c
@@ -7,6 +7,7 @@
 
 /* termios support is required */
 #include <jim-tty.h>
+#include <sys/ioctl.h>
 #include <termios.h>
 
 static const struct {
@@ -349,3 +350,94 @@ badvalue:
     }
     return 0;
 }
+
+Jim_Obj *Jim_GetTtyControlSettings(Jim_Interp *interp, int fd)
+{
+    size_t i;
+    Jim_Obj *listObjPtr;
+    int status;
+    static const struct {
+        const char * const name;
+        int value;
+    } modem_signals[] = {
+        { "rts", TIOCM_RTS },
+        { "dtr", TIOCM_DTR },
+
+        { "dcd", TIOCM_CAR },
+        { "dsr", TIOCM_DSR },
+        { "ring", TIOCM_RNG },
+        { "cts", TIOCM_CTS },
+    };
+
+    if (ioctl(fd, TIOCMGET, &status) < 0) {
+        return NULL;
+    }
+
+    listObjPtr = Jim_NewListObj(interp, NULL, 0);
+    for (i = 0; i < ARRAYSIZE(modem_signals); i++) {
+        Jim_ListAppendElement(interp, listObjPtr, Jim_NewStringObj(interp, modem_signals[i].name, -1));
+        Jim_ListAppendElement(interp, listObjPtr, Jim_NewIntObj(interp, (status & modem_signals[i].value & status) != 0));
+    }
+    return listObjPtr;
+}
+
+int Jim_SetTtyControlSettings(Jim_Interp *interp, int fd, Jim_Obj *dictObjPtr)
+{
+    static const char * const modem_signal_names[] = {
+        "rts", "dtr", "break", NULL
+    };
+    enum { OPT_RTS, OPT_DTR, OPT_BREAK, };
+    int len = Jim_ListLength(interp, dictObjPtr);
+    int i;
+
+    int status;
+
+    /* Get the current status of DTR and RTS in case we aren't setting everything */
+    if (ioctl(fd, TIOCMGET, &status) < 0) {
+        return -1;
+    }
+
+    for (i = 0; i < len; i += 2) {
+        Jim_Obj *nameObj = Jim_ListGetIndex(interp, dictObjPtr, i);
+        Jim_Obj *valueObj = Jim_ListGetIndex(interp, dictObjPtr, i + 1);
+        int opt;
+        long l;
+
+        if (Jim_GetEnum(interp, nameObj, modem_signal_names, &opt, "signal", JIM_ERRMSG | JIM_ENUM_ABBREV) != JIM_OK) {
+            return JIM_ERR;
+        }
+        if (Jim_GetLong(interp, valueObj, &l) != JIM_OK) {
+            Jim_SetResultFormatted(interp, "bad value for %#s: %#s", nameObj, valueObj);
+            return JIM_ERR;
+        }
+
+        switch (opt) {
+            case OPT_RTS:
+                if (l) {
+                    status |= TIOCM_RTS;
+                }
+                else {
+                    status &= ~TIOCM_RTS;
+                }
+                break;
+
+            case OPT_DTR:
+                if (l) {
+                    status |= TIOCM_DTR;
+                }
+                else {
+                    status &= ~TIOCM_DTR;
+                }
+                break;
+
+            case OPT_BREAK:
+                tcsendbreak(fd, l);
+                break;
+        }
+    }
+
+    if (ioctl(fd, TIOCMSET, &status) < 0) {
+        return -1;
+    }
+    return JIM_OK;
+}
diff --git a/jim-tty.h b/jim-tty.h
index d052d73..bf1ad7f 100644
--- a/jim-tty.h
+++ b/jim-tty.h
@@ -23,6 +23,22 @@ Jim_Obj *Jim_GetTtySettings(Jim_Interp *interp, int fd);
  */
 int Jim_SetTtySettings(Jim_Interp *interp, int fd, Jim_Obj *dictObjPtr);
 
+/**
+ * Return the tty modem control settings for the given file descriptor as a dictionary
+ * with a zero reference count.
+ *
+ * Returns NULL and sets errno file descriptor is not a valid tty.
+ */
+Jim_Obj *Jim_GetTtyControlSettings(Jim_Interp *interp, int fd);
+
+/**
+ * Sets the tty modem control settings given in 'dictObjPtr'
+ *
+ * Returns JIM_OK if OK, JIM_ERR if any settings are invalid,
+ * or -1 (and sets errno) if the file descriptor is not a valid tty.
+ */
+int Jim_SetTtyControlSettings(Jim_Interp *interp, int fd, Jim_Obj *dictObjPtr);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/jim_tcl.txt b/jim_tcl.txt
index 05a2e26..9cfa6f8 100644
--- a/jim_tcl.txt
+++ b/jim_tcl.txt
@@ -5136,7 +5136,7 @@ This command returns an empty string.
 
 +$handle *tty* ?settings?+::
     If no arguments are given, returns a dictionary containing the tty settings for the stream.
-    If arguments are given, they must either be a dictionary, or +setting value \...+
+    If arguments are given, they must either be a dictionary, or +setting value \...+.
     Abbreviations are supported for both settings and values, so the following is acceptable:
     +$f tty parity e input c out raw+.
     Only available on platforms that support 'termios(3)'. Supported settings are:
@@ -5179,6 +5179,25 @@ This command returns an empty string.
     +*vstop* 'char'+;;
         Stop character for xonoff, usually 0x13 (^S)
 
++$handle *ttycontrol* ?settings?+::
+    If no arguments are given, returns a dictionary containing the modem control signals
+    from the stream (must be a serial-type device). e.g. +{rts 1 dtr 1 dcd 0 dsr 0 ring 0 cts 0}+.
+    Note that +rts+ and +dtr+ are controlled by the local system while the other signals reflect
+    the remote system.
+    If arguments are given, they must either be a dictionary, or +setting value \...+.
+    Abbreviations are supported for both settings and values.
+    Supported settings are:
+
+    +*rts 0|1*+;;
+        Set the RTS (Request To Send) signal
+
+    +*dtr 0|1*+;;
+        Set the DTR (Data Terminal Ready) signal
+
+    +*break* 'duration'+;;
+        Generate a break condition. +duration+ is generally ignored but may be used
+        in a platform-dependent manner.
+
 +$handle *ssl* ?*-server* 'cert ?key?'|*-sni* 'servername'?+::
     Upgrades the stream to a SSL/TLS session and returns the handle.
     If +-server+ is specified, either both the certificate and private key files