gdb: unix: allow to use custom baud rate

Modern unix systems allow to set custom baud rate instead of predefined in termios.h.

- To use this in Linux it must have BOTHER macro in "asm/termio.h"
- MacOS could handle this using IOSSIOSPEED passed to ioctl()

Approved-By: Simon Marchi <simon.marchi@efficios.com>
Change-Id: I5bc95982f5d90c7030b73f484ecc0f75c060ebf7

4 files changed, 139 insertions, 7 deletions

diff --git a/gdb/config.in b/gdb/config.in
index c0a050c..149aeaf 100644
--- a/gdb/config.in
+++ b/gdb/config.in
@@ -96,6 +96,9 @@
 /* Define if amd-dbgapi is being linked in. */
 #undef HAVE_AMD_DBGAPI
 
+/* Define to 1 if you have the <asm/termios.h> header file. */
+#undef HAVE_ASM_TERMIOS_H
+
 /* Define to 1 if you have the `btowc' function. */
 #undef HAVE_BTOWC
 
@@ -247,6 +250,9 @@
 /* Define to 1 if you have the <inttypes.h> header file. */
 #undef HAVE_INTTYPES_H
 
+/* Define to 1 if you have the <IOKit/serial/ioss.h> header file. */
+#undef HAVE_IOKIT_SERIAL_IOSS_H
+
 /* Define to 1 if you have the `kinfo_getfile' function. */
 #undef HAVE_KINFO_GETFILE
 
diff --git a/gdb/configure b/gdb/configure
index 866ddce..8fc3b04 100755
--- a/gdb/configure
+++ b/gdb/configure
@@ -29263,6 +29263,8 @@ $as_echo "#define STDC_HEADERS 1" >>confdefs.h
 fi
 
 for ac_header in  \
+  IOKit/serial/ioss.h \
+  asm/termios.h \
   machine/reg.h \
   nlist.h \
   ptrace.h \
diff --git a/gdb/configure.ac b/gdb/configure.ac
index 52405f4..226e27e 100644
--- a/gdb/configure.ac
+++ b/gdb/configure.ac
@@ -1357,6 +1357,8 @@ AC_SUBST(SRCHIGH_CFLAGS)
 
 AC_HEADER_STDC
 AC_CHECK_HEADERS([ \
+  IOKit/serial/ioss.h \
+  asm/termios.h \
   machine/reg.h \
   nlist.h \
   ptrace.h \
diff --git a/gdb/ser-unix.c b/gdb/ser-unix.c
index db614c8..cc81e3b 100644
--- a/gdb/ser-unix.c
+++ b/gdb/ser-unix.c
@@ -30,9 +30,33 @@
 #include "gdbsupport/gdb_select.h"
 #include "cli/cli-cmds.h"
 #include "gdbsupport/filestuff.h"
-#include <termios.h>
+
+#ifdef HAVE_SYS_IOCTL_H
+#  include <sys/ioctl.h>
+#endif
+
+#if HAVE_IOKIT_SERIAL_IOSS_H
+#  include <IOKit/serial/ioss.h>
+#endif
+
+#if HAVE_ASM_TERMIOS_H
+/* Workaround to resolve conflicting declarations of termios
+   in <asm/termbits.h> and <termios.h>.  */
+#  define termios asmtermios
+#  include <asm/termbits.h>
+#  undef termios
+#endif
+
+#ifdef HAVE_TERMIOS_H
+#  include <termios.h>
+#endif
+
 #include "gdbsupport/scoped_ignore_sigttou.h"
 
+#if defined(HAVE_SYS_IOCTL_H) && (defined(BOTHER) || defined(IOSSIOSPEED))
+#  define HAVE_CUSTOM_BAUDRATE_SUPPORT 1
+#endif
+
 struct hardwire_ttystate
   {
     struct termios termios;
@@ -436,6 +460,7 @@ rate_to_code (int rate)
 	  /* check if it is in between valid values.  */
 	  if (rate < baudtab[i].rate)
 	    {
+#if !HAVE_CUSTOM_BAUDRATE_SUPPORT
 	      if (i)
 		{
 		  error (_("Invalid baud rate %d.  "
@@ -447,29 +472,126 @@ rate_to_code (int rate)
 		  error (_("Invalid baud rate %d.  Minimum value is %d."),
 			 rate, baudtab[0].rate);
 		}
+#else
+	      return -1;
+#endif
 	    }
 	}
     }
- 
+
+#if !HAVE_CUSTOM_BAUDRATE_SUPPORT
   /* The requested speed was too large.  */
   error (_("Invalid baud rate %d.  Maximum value is %d."),
 	 rate, baudtab[i - 1].rate);
+#else
+  return -1;
+#endif
 }
 
+/* Set baud rate using B_code from termios.h.  */
+
 static void
-hardwire_setbaudrate (struct serial *scb, int rate)
+set_baudcode_baudrate (struct serial *scb, int baud_code)
 {
   struct hardwire_ttystate state;
-  int baud_code = rate_to_code (rate);
-  
+
   if (get_tty_state (scb, &state))
-    perror_with_name ("could not get tty state");
+    perror_with_name (_("could not get tty state"));
 
   cfsetospeed (&state.termios, baud_code);
   cfsetispeed (&state.termios, baud_code);
 
   if (set_tty_state (scb, &state))
-    perror_with_name ("could not set tty state");
+    perror_with_name (_("could not set tty state"));
+}
+
+#if HAVE_CUSTOM_BAUDRATE_SUPPORT && defined(BOTHER)
+
+/* Set a custom baud rate using the termios BOTHER.  */
+
+static void
+set_custom_baudrate_linux (int fd, int rate)
+{
+#ifdef TCGETS2
+  struct termios2 tio;
+  const unsigned long req_get = TCGETS2;
+  const unsigned long req_set = TCSETS2;
+#else
+  struct termios tio;
+  const unsigned long req_get = TCGETS;
+  const unsigned long req_set = TCSETS;
+#endif
+
+  if (ioctl (fd, req_get, &tio) < 0)
+    perror_with_name (_("Can not get current baud rate"));
+
+  /* Clear the current output baud rate and fill a new value.  */
+  tio.c_cflag &= ~CBAUD;
+  tio.c_cflag |= BOTHER;
+  tio.c_ospeed = rate;
+
+  /* Clear the current input baud rate and fill a new value.  */
+  tio.c_cflag &= ~(CBAUD << IBSHIFT);
+  tio.c_cflag |= BOTHER << IBSHIFT;
+  tio.c_ispeed = rate;
+
+  if (ioctl (fd, req_set, &tio) < 0)
+    perror_with_name (_("Can not set custom baud rate"));
+}
+
+#elif HAVE_CUSTOM_BAUDRATE_SUPPORT && defined(IOSSIOSPEED)
+
+/* Set a custom baud rate using the IOSSIOSPEED ioctl call.  */
+
+static void
+set_custom_baudrate_darwin (int fd, int rate)
+{
+
+  if (ioctl (fd, IOSSIOSPEED, &rate) < 0)
+    perror_with_name (_("Can not set custom baud rate"));
+}
+
+#endif /* HAVE_CUSTOM_BAUDRATE_SUPPORT
+	  && (defined(BOTHER) || defined(IOSSIOSPEED)) */
+
+#if HAVE_CUSTOM_BAUDRATE_SUPPORT
+
+/* Set a baud rate that differs from the OS B_codes.
+   This is possible if one of the following macros is available:
+   - BOTHER (Linux).
+   - IOSSIOSPEED (Darwin).  */
+
+static void
+set_custom_baudrate (int fd, int rate)
+{
+#if defined(BOTHER)
+  set_custom_baudrate_linux (fd, rate);
+#elif defined(IOSSIOSPEED)
+  set_custom_baudrate_darwin (fd, rate);
+#endif
+}
+
+#endif /* HAVE_CUSTOM_BAUDRATE_SUPPORT */
+
+/* Set the baud rate for the serial communication.  */
+
+static void
+hardwire_setbaudrate (struct serial *scb, int rate)
+{
+  int baud_code = rate_to_code (rate);
+
+  if (baud_code < 0)
+    {
+#if HAVE_CUSTOM_BAUDRATE_SUPPORT
+      set_custom_baudrate (scb->fd, rate);
+#else
+      /* An error should already have been thrown by rate_to_code().
+	 Add an additional error in case execution somehow reaches this line.  */
+      gdb_assert_not_reached (_("Serial baud rate was not found in B_codes"));
+#endif
+    }
+  else
+    set_baudcode_baudrate (scb, baud_code);
 }
 
 static int