From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 11919 invoked by alias); 23 Apr 2011 08:00:59 -0000 Received: (qmail 11909 invoked by uid 22791); 23 Apr 2011 08:00:57 -0000 X-SWARE-Spam-Status: No, hits=-6.4 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,SPF_HELO_PASS,T_FRT_STOCK2,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Sat, 23 Apr 2011 08:00:36 +0000 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p3N80S4N026788 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Sat, 23 Apr 2011 04:00:28 -0400 Received: from host1.jankratochvil.net (ovpn01.gateway.prod.ext.phx2.redhat.com [10.5.9.1]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id p3N80P79008914 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Sat, 23 Apr 2011 04:00:27 -0400 Received: from host1.jankratochvil.net (localhost [127.0.0.1]) by host1.jankratochvil.net (8.14.4/8.14.4) with ESMTP id p3N80OPN019897; Sat, 23 Apr 2011 10:00:24 +0200 Received: (from jkratoch@localhost) by host1.jankratochvil.net (8.14.4/8.14.4/Submit) id p3N80NAk019891; Sat, 23 Apr 2011 10:00:23 +0200 Date: Sat, 23 Apr 2011 08:00:00 -0000 From: Jan Kratochvil To: Eli Zaretskii Cc: pedro@codesourcery.com, gdb-patches@sourceware.org, dan@codesourcery.com Subject: Re: [patch] [gdbserver] Fix multi-GB error log files [doc review] Message-ID: <20110423080023.GA19201@host1.jankratochvil.net> References: <20110306115536.GA31532@host1.jankratochvil.net> <201103151941.16708.pedro@codesourcery.com> <20110316093228.GA27281@host1.jankratochvil.net> <201103161013.41848.pedro@codesourcery.com> <20110417140428.GA2085@host1.jankratochvil.net> <83y638on5c.fsf@gnu.org> <20110422214145.GA11969@host1.jankratochvil.net> <83vcy5biid.fsf@gnu.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <83vcy5biid.fsf@gnu.org> User-Agent: Mutt/1.5.21 (2010-09-15) X-IsSubscribed: yes Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2011-04/txt/msg00423.txt.bz2 On Sat, 23 Apr 2011 08:15:38 +0200, Eli Zaretskii wrote: > GDBserver now keeps its listening port open, unless you start > GDBserver with the --once option. Keeping the listening port open > allows subsequent reconnections from another GDB session. BTW personally I read it as if GDBserver did not support reconnections before and that reconnections are a new feature (which they are not). > > + Option @option{--multi} is not directly related > > +to @kbd{target extended-remote} (therefore @kbd{target remote} is also > > +compatible) and vice versa. > > It's not clear to me how this sentence is related to the surrounding > text. What potential problem did you try to prevent by that? Yes, I was considering to post it as a separate patch but (a) it would be a hassle for one sentence and (b) it is all related together anyway. --multi, remote/extended-remote and --once all together affect when gdbserver will / will not terminate. Normally AFAIK one uses either: --multi with extended-remote or (default) with remote so I was curious if one can mix the two modes. And to my surprise gdbserver behavior in which cases it terminates depends on how GDB connects to it (remote/extended-remote) instead of the gdbserver arguments (--multi). This is why this question seemed to me logical in the context of explaining all the GDB termination rules which needed to be explained together with the port allocation rules. > > +terminated in @kbd{target remote} mode. On the other hand for @kbd{target > ^ > Missing comma there. You wrote it as "On the other, hand for " but I have used "On the other hand, for ", either a typo or a font layout problem on your side. > > + The purpose of option > > +@option{--once} is to enable reusing the same port number for connections to > > +multiple @code{gdbserver}s running at the same host. > > "The purpose of the @option{--once} option is ..." > > However, is the above the only purpose of this option? If not, saying > "the purpose" is inaccurate. Not the only one, it is also useful if any unexpected situation happens in the testsuite gdbserver will no longer be needlessly running. > How about the following rewording: Used. > * gdb.texinfo (Server): Improve indexing. Index all optional > switches to gdbserver. Added @cindex for --once. Used all your other suggestions, I am not aware much of the commas. I will check it in if no futher comments appear. Thanks, Jan gdb/gdbserver/ 2011-04-23 Jan Kratochvil * NEWS: Document the new gdbserver --once option. * remote-utils.c (handle_accept_event): Close LISTEN_DESC only if RUN_ONCE. Comment for the LISTEN_DESC delete_file_handler call. (remote_prepare): New function with most of the TCP code from ... (remote_open): ... here. Detect PORT here unconditionally. Move also setting transport_is_reliable. * server.c (run_once): New variable. (gdbserver_usage): Document it. (main): Set run_once for `--once'. Call remote_prepare. Exit after the first run if RUN_ONCE. * server.h (run_once, remote_prepare): New declarations. gdb/doc/ 2011-04-23 Jan Kratochvil Eli Zaretskii * gdb.texinfo (Starting and Stopping Trace Experiments): New anchor for disconnected tracing. (Multi-Process Mode for @code{gdbserver}): Mention --multi and extended-remote relationship. Mention --once. (TCP port allocation lifecycle of @code{gdbserver}): New. gdb/testsuite/ 2011-04-17 Jan Kratochvil * gdb.base/solib-disc.exp: Set gdbserver_reconnect_p. * lib/gdb.exp (gdb_init): Clear gdbserver_reconnect_p. * lib/gdbserver-support.exp (gdbserver_start): Add `--once' if !gdbserver_reconnect_p.. (gdbserver_reconnect): Call error if !gdbserver_reconnect_p.. --- a/gdb/NEWS +++ b/gdb/NEWS @@ -3,6 +3,10 @@ *** Changes since GDB 7.3 +* GDBserver now keeps its listening port open, unless you start GDBserver with + the --once option. Keeping the listening port open allows subsequent + reconnections from another GDB session. + *** Changes in GDB 7.3 * GDB has a new command: "thread find [REGEXP]". --- a/gdb/doc/gdb.texinfo +++ b/gdb/doc/gdb.texinfo @@ -10435,6 +10435,7 @@ Enter actions for tracepoint #1, one per line. (@value{GDBP}) @b{tstop} @end smallexample +@anchor{disconnected tracing} @cindex disconnected tracing You can choose to continue running the trace experiment even if @value{GDBN} disconnects from the target, voluntarily or @@ -16230,11 +16231,43 @@ redirection (@pxref{Arguments}). To start @code{gdbserver} without supplying an initial command to run or process ID to attach, use the @option{--multi} command line option. Then you can connect using @kbd{target extended-remote} and start -the program you want to debug. - -@code{gdbserver} does not automatically exit in multi-process mode. -You can terminate it by using @code{monitor exit} -(@pxref{Monitor Commands for gdbserver}). +the program you want to debug. The @option{--multi} option is not directly +related to @kbd{target extended-remote} (therefore @kbd{target remote} is also +compatible) and vice versa. + +In multi-process mode @code{gdbserver} does not automatically exit unless you +use the option @option{--once}. You can terminate it by using +@code{monitor exit} (@pxref{Monitor Commands for gdbserver}). + +@subsubsection TCP port allocation lifecycle of @code{gdbserver} + +This section applies only when @code{gdbserver} is run to listen on a TCP port. + +@code{gdbserver} normally terminates after all of its debugged processes have +terminated in @kbd{target remote} mode. On the other hand, for @kbd{target +extended-remote}, @code{gdbserver} stays running even with no processes left. +@value{GDBN} normally terminates the spawned debugged process on its exit, +which normally also terminates @code{gdbserver} in the @kbd{target remote} +mode. Therefore, when the connection drops unexpectedly, and @value{GDBN} +cannot ask @code{gdbserver} to kill its debugged processes, @code{gdbserver} +stays running even in the @kbd{target remote} mode. + +When @code{gdbserver} stays running, @value{GDBN} can connect to it again later. +Such reconnecting is useful for features like @ref{disconnected tracing}. For +completeness, at most one @value{GDBN} can be connected at a time. + +@cindex @option{--once}, @code{gdbserver} option +By default, @code{gdbserver} keeps the listening TCP port open, so that +additional connections are possible. However, if you start @code{gdbserver} +with the @option{--once} option, it will stop listening for any further +connection attempts after connecting to the first @value{GDBN} session. This +means no further connections to @code{gdbserver} will be possible after the +first one. It also means @code{gdbserver} will terminate after the first +connection with remote @value{GDBN} has closed, even for unexpectedly closed +connections and even in the @kbd{target extended-remote} mode. The +@option{--once} option allows reusing the same port number for connecting to +multiple instances of @code{gdbserver} running on the same host, since each +instance closes its port after the first connection. @subsubsection Other Command-Line Arguments for @code{gdbserver} --- a/gdb/gdbserver/remote-utils.c +++ b/gdb/gdbserver/remote-utils.c @@ -170,14 +170,21 @@ handle_accept_event (int err, gdb_client_data client_data) (char *) &tmp, sizeof (tmp)); #ifndef USE_WIN32API - close (listen_desc); /* No longer need this */ - signal (SIGPIPE, SIG_IGN); /* If we don't do this, then gdbserver simply exits when the remote side dies. */ +#endif + + if (run_once) + { +#ifndef USE_WIN32API + close (listen_desc); /* No longer need this */ #else - closesocket (listen_desc); /* No longer need this */ + closesocket (listen_desc); /* No longer need this */ #endif + } + /* Even if !RUN_ONCE no longer notice new connections. Still keep the + descriptor open for add_file_handler to wait for a new connection. */ delete_file_handler (listen_desc); /* Convert IP address to string. */ @@ -200,6 +207,62 @@ handle_accept_event (int err, gdb_client_data client_data) return 0; } +/* Prepare for a later connection to a remote debugger. + NAME is the filename used for communication. */ + +void +remote_prepare (char *name) +{ + char *port_str; +#ifdef USE_WIN32API + static int winsock_initialized; +#endif + int port; + struct sockaddr_in sockaddr; + socklen_t tmp; + char *port_end; + + port_str = strchr (name, ':'); + if (port_str == NULL) + { + transport_is_reliable = 0; + return; + } + + port = strtoul (port_str + 1, &port_end, 10); + if (port_str[1] == '\0' || *port_end != '\0') + fatal ("Bad port argument: %s", name); + +#ifdef USE_WIN32API + if (!winsock_initialized) + { + WSADATA wsad; + + WSAStartup (MAKEWORD (1, 0), &wsad); + winsock_initialized = 1; + } +#endif + + listen_desc = socket (PF_INET, SOCK_STREAM, IPPROTO_TCP); + if (listen_desc == -1) + perror_with_name ("Can't open socket"); + + /* Allow rapid reuse of this port. */ + tmp = 1; + setsockopt (listen_desc, SOL_SOCKET, SO_REUSEADDR, (char *) &tmp, + sizeof (tmp)); + + sockaddr.sin_family = PF_INET; + sockaddr.sin_port = htons (port); + sockaddr.sin_addr.s_addr = INADDR_ANY; + + if (bind (listen_desc, (struct sockaddr *) &sockaddr, sizeof (sockaddr)) + || listen (listen_desc, 1)) + perror_with_name ("Can't bind address"); + + transport_is_reliable = 1; +} + /* Open a connection to a remote debugger. NAME is the filename used for communication. */ @@ -274,8 +337,6 @@ remote_open (char *name) fprintf (stderr, "Remote debugging using %s\n", name); - transport_is_reliable = 0; - enable_async_notification (remote_desc); /* Register the event loop handler. */ @@ -284,64 +345,22 @@ remote_open (char *name) } else { -#ifdef USE_WIN32API - static int winsock_initialized; -#endif int port; + socklen_t len; struct sockaddr_in sockaddr; - socklen_t tmp; - char *port_end; - port = strtoul (port_str + 1, &port_end, 10); - if (port_str[1] == '\0' || *port_end != '\0') - fatal ("Bad port argument: %s", name); - -#ifdef USE_WIN32API - if (!winsock_initialized) - { - WSADATA wsad; - - WSAStartup (MAKEWORD (1, 0), &wsad); - winsock_initialized = 1; - } -#endif - - listen_desc = socket (PF_INET, SOCK_STREAM, IPPROTO_TCP); - if (listen_desc == -1) - perror_with_name ("Can't open socket"); - - /* Allow rapid reuse of this port. */ - tmp = 1; - setsockopt (listen_desc, SOL_SOCKET, SO_REUSEADDR, (char *) &tmp, - sizeof (tmp)); - - sockaddr.sin_family = PF_INET; - sockaddr.sin_port = htons (port); - sockaddr.sin_addr.s_addr = INADDR_ANY; - - if (bind (listen_desc, (struct sockaddr *) &sockaddr, sizeof (sockaddr)) - || listen (listen_desc, 1)) - perror_with_name ("Can't bind address"); - - /* If port is zero, a random port will be selected, and the - fprintf below needs to know what port was selected. */ - if (port == 0) - { - socklen_t len = sizeof (sockaddr); - if (getsockname (listen_desc, - (struct sockaddr *) &sockaddr, &len) < 0 - || len < sizeof (sockaddr)) - perror_with_name ("Can't determine port"); - port = ntohs (sockaddr.sin_port); - } + len = sizeof (sockaddr); + if (getsockname (listen_desc, + (struct sockaddr *) &sockaddr, &len) < 0 + || len < sizeof (sockaddr)) + perror_with_name ("Can't determine port"); + port = ntohs (sockaddr.sin_port); fprintf (stderr, "Listening on port %d\n", port); fflush (stderr); /* Register the event loop handler. */ add_file_handler (listen_desc, handle_accept_event, NULL); - - transport_is_reliable = 1; } } --- a/gdb/gdbserver/server.c +++ b/gdb/gdbserver/server.c @@ -40,6 +40,9 @@ static int extended_protocol; static int response_needed; static int exit_requested; +/* --once: Exit after the first connection has closed. */ +int run_once; + int multi_process; int non_stop; @@ -2312,7 +2315,9 @@ gdbserver_usage (FILE *stream) " --debug Enable general debugging output.\n" " --remote-debug Enable remote protocol debugging output.\n" " --version Display version information and exit.\n" - " --wrapper WRAPPER -- Run WRAPPER to start new programs.\n"); + " --wrapper WRAPPER -- Run WRAPPER to start new programs.\n" + " --once Exit after the first connection has " + "closed.\n"); if (REPORT_BUGS_TO[0] && stream == stdout) fprintf (stream, "Report bugs to \"%s\".\n", REPORT_BUGS_TO); } @@ -2536,6 +2541,8 @@ main (int argc, char *argv[]) } } } + else if (strcmp (*next_arg, "--once") == 0) + run_once = 1; else { fprintf (stderr, "Unknown argument: %s\n", *next_arg); @@ -2648,6 +2655,8 @@ main (int argc, char *argv[]) exit (1); } + remote_prepare (port); + while (1) { noack_mode = 0; @@ -2676,7 +2685,7 @@ main (int argc, char *argv[]) getpkt to fail; close the connection and reopen it at the top of the loop. */ - if (exit_requested) + if (exit_requested || run_once) { detach_or_kill_for_exit (); exit (0); --- a/gdb/gdbserver/server.h +++ b/gdb/gdbserver/server.h @@ -355,6 +355,7 @@ extern int disable_packet_Tthread; extern int disable_packet_qC; extern int disable_packet_qfThreadInfo; +extern int run_once; extern int multi_process; extern int non_stop; @@ -406,6 +407,7 @@ int putpkt (char *buf); int putpkt_binary (char *buf, int len); int putpkt_notif (char *buf); int getpkt (char *buf); +void remote_prepare (char *name); void remote_open (char *name); void remote_close (void); void write_ok (char *buf); --- a/gdb/testsuite/gdb.base/solib-disc.exp +++ b/gdb/testsuite/gdb.base/solib-disc.exp @@ -19,6 +19,7 @@ if {[skip_shlib_tests]} { return 0 } +set gdbserver_reconnect_p 1 if { [info proc gdb_reconnect] == "" } { return 0 } --- a/gdb/testsuite/lib/gdb.exp +++ b/gdb/testsuite/lib/gdb.exp @@ -2809,6 +2809,11 @@ proc gdb_init { args } { # especially having color output turned on can cause tests to fail. setenv GREP_OPTIONS "" + # Clear $gdbserver_reconnect_p. + global gdbserver_reconnect_p + set gdbserver_reconnect_p 1 + unset gdbserver_reconnect_p + return [eval default_gdb_init $args]; } --- a/gdb/testsuite/lib/gdbserver-support.exp +++ b/gdb/testsuite/lib/gdbserver-support.exp @@ -218,10 +218,21 @@ proc gdbserver_start { options arguments } { # Fire off the debug agent. set gdbserver_command "$gdbserver" + + # If gdbserver_reconnect will be called $gdbserver_reconnect_p must be + # set to true already during gdbserver_start. + global gdbserver_reconnect_p + if {![info exists gdbserver_reconnect_p] || !$gdbserver_reconnect_p} { + # GDB client could accidentally connect to a stale server. + append gdbserver_command " --once" + } + if { $options != "" } { append gdbserver_command " $options" } + append gdbserver_command " :$portnum" + if { $arguments != "" } { append gdbserver_command " $arguments" } @@ -315,6 +326,12 @@ proc gdbserver_reconnect { } { global gdbserver_protocol global gdbserver_gdbport + global gdbserver_reconnect_p; + if {![info exists gdbserver_reconnect_p] || !$gdbserver_reconnect_p} { + error "gdbserver_reconnect_p is not set before gdbserver_reconnect" + return 0 + } + return [gdb_target_cmd $gdbserver_protocol $gdbserver_gdbport] }