From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 17423 invoked by alias); 13 May 2002 17:42:04 -0000 Mailing-List: contact gdb-patches-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sources.redhat.com Received: (qmail 17416 invoked from network); 13 May 2002 17:42:02 -0000 Received: from unknown (HELO nevyn.them.org) (128.2.145.6) by sources.redhat.com with SMTP; 13 May 2002 17:42:02 -0000 Received: from drow by nevyn.them.org with local (Exim 3.35 #1 (Debian)) id 177JpZ-0003O1-00; Mon, 13 May 2002 13:41:53 -0400 Date: Mon, 13 May 2002 10:42:00 -0000 From: Daniel Jacobowitz To: Andrew Cagney Cc: Michael Snyder , gdb-patches@sources.redhat.com Subject: Re: [RFA] Remote UDP support Message-ID: <20020513174153.GA9168@nevyn.them.org> Mail-Followup-To: Andrew Cagney , Michael Snyder , gdb-patches@sources.redhat.com References: <20020509030123.GA7864@nevyn.them.org> <3CDABEB1.5008A502@redhat.com> <20020509184410.GA28420@nevyn.them.org> <3CDAE78A.7080508@cygnus.com> <20020509212046.GA3964@nevyn.them.org> <3CDD6D3E.90809@cygnus.com> <20020511213218.GA8246@nevyn.them.org> <3CDD94DB.8070409@cygnus.com> <20020513012154.GB17951@nevyn.them.org> <3CDF449F.7020300@cygnus.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3CDF449F.7020300@cygnus.com> User-Agent: Mutt/1.5.1i X-SW-Source: 2002-05/txt/msg00478.txt.bz2 On Mon, May 13, 2002 at 12:44:15AM -0400, Andrew Cagney wrote: > >How's this look? I wasn't quite sure what to put in the text of the > >>>warning. Also added one to the manual. > > > >> > >>Problem is, its in the wrong place, and I suspect getting it into the > >>right place - remote.c - is tricky. > >> > >>I think adding a FIXME hack to remote.c (search for serial_open) that > >>checks for ``udp:'' and then print a warning is the most pratical. > > > > > >I don't understand. Why hoist it up into remote.c, before each call to > >serial_open? That just descends through serial_open to call net_open > >and the warning would arrive at the same position; the warning is > >specific to ser-tcp, and seems to belong there. > > Sorry, yes the rationale was a big bit vague :-( > > serial_open() provides a generic serial connection. Data that goes in > one end, hopefully, comes out the other end - it doesn't promise to be > reliable though. > > remote.c, on the other hand, makes certain assumptions about the > properties of the SERIAL object it is using (only data overrun is > possible, single character transfers are reliable, ...). Hence, I think > remote.c should be the one reporting a potential problem. > > Besides, if someone were to implement a remote-udp.c the warning would > be wrong :-) OK, that did it. Now I understand why you wanted it. Is this better? -- Daniel Jacobowitz Carnegie Mellon University MontaVista Software Debian GNU/Linux Developer 2002-05-08 Daniel Jacobowitz * ser-tcp.c: Include . Rename tcp_open and tcp_close to net_open and net_close. (net_open): Accept "udp:" and "tcp:" specifications. Connect using UDP if requested. Don't try to disable Nagle on UDP sockets. * remote.c (remote_serial_open): New function. Warn about UDP. (remote_open_1, remote_async_open_1, remote_cisco_open): Call it. 2002-05-08 Daniel Jacobowitz * gdb.texinfo (Debug Session): Document new `udp:' and `tcp:' options for `target remote'. Index: remote.c =================================================================== RCS file: /cvs/src/src/gdb/remote.c,v retrieving revision 1.80 diff -u -p -r1.80 remote.c --- remote.c 12 May 2002 01:02:58 -0000 1.80 +++ remote.c 13 May 2002 16:34:59 -0000 @@ -2222,6 +2222,26 @@ remote_check_symbols (struct objfile *ob } } +static struct serial * +remote_serial_open (char *name) +{ + static int udp_warning = 0; + + /* FIXME: Parsing NAME here is a hack. But we want to warn here instead + of in ser-tcp.c, because it is the remote protocol assuming that the + serial connection is reliable and not the serial connection promising + to be. */ + if (!udp_warning && strncmp (name, "udp:", 4) == 0) + { + warning ("The remote protocol may be unreliable over UDP."); + warning ("Some events may be lost, rendering further debugging " + "impossible."); + udp_warning = 1; + } + + return serial_open (name); +} + static void remote_open_1 (char *name, int from_tty, struct target_ops *target, int extended_p) @@ -2239,7 +2259,7 @@ remote_open_1 (char *name, int from_tty, unpush_target (target); - remote_desc = serial_open (name); + remote_desc = remote_serial_open (name); if (!remote_desc) perror_with_name (name); @@ -2337,7 +2357,7 @@ remote_async_open_1 (char *name, int fro unpush_target (target); - remote_desc = serial_open (name); + remote_desc = remote_serial_open (name); if (!remote_desc) perror_with_name (name); @@ -5463,7 +5483,7 @@ remote_cisco_open (char *name, int from_ unpush_target (&remote_cisco_ops); - remote_desc = serial_open (name); + remote_desc = remote_serial_open (name); if (!remote_desc) perror_with_name (name); Index: ser-tcp.c =================================================================== RCS file: /cvs/src/src/gdb/ser-tcp.c,v retrieving revision 1.10 diff -u -p -r1.10 ser-tcp.c --- ser-tcp.c 18 Dec 2001 18:54:18 -0000 1.10 +++ ser-tcp.c 13 May 2002 16:34:59 -0000 @@ -38,12 +38,13 @@ #include #include #include +#include #include #include "gdb_string.h" -static int tcp_open (struct serial *scb, const char *name); -static void tcp_close (struct serial *scb); +static int net_open (struct serial *scb, const char *name); +static void net_close (struct serial *scb); extern int (*ui_loop_hook) (int); void _initialize_ser_tcp (void); @@ -55,17 +56,27 @@ void _initialize_ser_tcp (void); /* Open a tcp socket */ static int -tcp_open (struct serial *scb, const char *name) +net_open (struct serial *scb, const char *name) { char *port_str, hostname[100]; int n, port, tmp; + int use_udp; struct hostent *hostent; struct sockaddr_in sockaddr; + use_udp = 0; + if (strncmp (name, "udp:", 4) == 0) + { + use_udp = 1; + name = name + 4; + } + else if (strncmp (name, "tcp:", 4) == 0) + name = name + 4; + port_str = strchr (name, ':'); if (!port_str) - error ("tcp_open: No colon in host name!"); /* Shouldn't ever happen */ + error ("net_open: No colon in host name!"); /* Shouldn't ever happen */ tmp = min (port_str - name, (int) sizeof hostname - 1); strncpy (hostname, name, tmp); /* Don't want colon */ @@ -84,7 +95,11 @@ tcp_open (struct serial *scb, const char return -1; } - scb->fd = socket (PF_INET, SOCK_STREAM, 0); + if (use_udp) + scb->fd = socket (PF_INET, SOCK_DGRAM, 0); + else + scb->fd = socket (PF_INET, SOCK_STREAM, 0); + if (scb->fd < 0) return -1; @@ -102,7 +117,7 @@ tcp_open (struct serial *scb, const char if (n < 0 && errno != EINPROGRESS) { - tcp_close (scb); + net_close (scb); return -1; } @@ -124,7 +139,7 @@ tcp_open (struct serial *scb, const char if (ui_loop_hook (0)) { errno = EINTR; - tcp_close (scb); + net_close (scb); return -1; } } @@ -142,7 +157,7 @@ tcp_open (struct serial *scb, const char { if (polls > TIMEOUT * POLL_INTERVAL) errno = ETIMEDOUT; - tcp_close (scb); + net_close (scb); return -1; } } @@ -156,20 +171,23 @@ tcp_open (struct serial *scb, const char { if (err) errno = err; - tcp_close (scb); + net_close (scb); return -1; } } - + /* turn off nonblocking */ tmp = 0; ioctl (scb->fd, FIONBIO, &tmp); - /* Disable Nagle algorithm. Needed in some cases. */ - tmp = 1; - setsockopt (scb->fd, IPPROTO_TCP, TCP_NODELAY, - (char *)&tmp, sizeof (tmp)); - + if (use_udp == 0) + { + /* Disable Nagle algorithm. Needed in some cases. */ + tmp = 1; + setsockopt (scb->fd, IPPROTO_TCP, TCP_NODELAY, + (char *)&tmp, sizeof (tmp)); + } + /* If we don't do this, then GDB simply exits when the remote side dies. */ signal (SIGPIPE, SIG_IGN); @@ -178,7 +196,7 @@ tcp_open (struct serial *scb, const char } static void -tcp_close (struct serial *scb) +net_close (struct serial *scb) { if (scb->fd < 0) return; @@ -194,8 +212,8 @@ _initialize_ser_tcp (void) memset (ops, sizeof (struct serial_ops), 0); ops->name = "tcp"; ops->next = 0; - ops->open = tcp_open; - ops->close = tcp_close; + ops->open = net_open; + ops->close = net_close; ops->readchar = ser_unix_readchar; ops->write = ser_unix_write; ops->flush_output = ser_unix_nop_flush_output; Index: doc/gdb.texinfo =================================================================== RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v retrieving revision 1.98 diff -u -p -r1.98 gdb.texinfo --- doc/gdb.texinfo 4 May 2002 16:00:30 -0000 1.98 +++ doc/gdb.texinfo 13 May 2002 16:35:22 -0000 @@ -10475,7 +10475,7 @@ of its pure text. Establish communication using the @code{target remote} command. Its argument specifies how to communicate with the target machine---either via a devicename attached to a direct serial line, or a -TCP port (usually to a terminal server which in turn has a serial line +TCP or UDP port (usually to a terminal server which in turn has a serial line to the target). For example, to use a serial line connected to the device named @file{/dev/ttyb}: @@ -10485,7 +10485,8 @@ target remote /dev/ttyb @cindex TCP port, @code{target remote} To use a TCP connection, use an argument of the form -@code{@var{host}:port}. For example, to connect to port 2828 on a +@code{@var{host}:@var{port}} or @code{tcp:@var{host}:@var{port}}. +For example, to connect to port 2828 on a terminal server named @code{manyfarms}: @smallexample @@ -10503,6 +10504,21 @@ target remote :1234 @noindent Note that the colon is still required here. + +@cindex UDP port, @code{target remote} +To use a UDP connection, use an argument of the form +@code{udp:@var{host}:@var{port}}. For example, to connect to UDP port 2828 +on a terminal server named @code{manyfarms}: + +@smallexample +target remote udp:manyfarms:2828 +@end smallexample + +When using a UDP connection for remote debugging, you should keep in mind +that the `U' stands for ``Unreliable''. UDP can silently drop packets on +busy or unreliable networks, which will cause havoc with your debugging +session. + @end enumerate Now you can use all the usual commands to examine and change data and to