From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 23201 invoked by alias); 10 May 2011 20:47:04 -0000 Received: (qmail 23180 invoked by uid 22791); 10 May 2011 20:47:02 -0000 X-SWARE-Spam-Status: No, hits=-2.4 required=5.0 tests=AWL,BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,SPF_HELO_PASS,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from smtp-out.google.com (HELO smtp-out.google.com) (74.125.121.67) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 10 May 2011 20:46:48 +0000 Received: from wpaz29.hot.corp.google.com (wpaz29.hot.corp.google.com [172.24.198.93]) by smtp-out.google.com with ESMTP id p4AKkhEU029710; Tue, 10 May 2011 13:46:43 -0700 Received: from ruffy.mtv.corp.google.com (ruffy.mtv.corp.google.com [172.18.118.116]) by wpaz29.hot.corp.google.com with ESMTP id p4AKkfOT030863; Tue, 10 May 2011 13:46:42 -0700 Received: by ruffy.mtv.corp.google.com (Postfix, from userid 67641) id A4C73246199; Tue, 10 May 2011 13:46:41 -0700 (PDT) To: gdb-patches@sourceware.org, pedro@codesourcery.com Subject: [RFA] Remove set debug lin-lwp-async, new ui_file.to_write_async_safe Message-Id: <20110510204641.A4C73246199@ruffy.mtv.corp.google.com> Date: Tue, 10 May 2011 20:47:00 -0000 From: dje@google.com (Doug Evans) X-System-Of-Record: true 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: 2011-05/txt/msg00259.txt.bz2 Hi. This patch does two things. 1) Remove debug_linux_nat_async, replacing all uses with debug_linux_nat. 2) Fix the debug printf in sigchld_handler. Adding to_write_async_safe (and the associated scaffolding) just for sigchld_handler may seem like a lot, but I *like* having a debug printf in sigchld_handler. And given that it might be invoked more often now, I think we need to fix it and use a more signal-safe debug printer. I haven't added the higher level of abstraction (fprintf_unfiltered_async_safe or some such) and, e.g. the associated gettimeofday handling. That can be done later if it's useful enough. Pedro mentioned there being a lot more output because of this. I like what's there now, but I can imagine some tweaking may be needed. I'd like to add some more debug printfs here, and I wouldn't mind having "set debug lin-lwp N" where N would specify a level of verbosity (0,1,2 at most probably). Ok to check in? 2011-05-10 Doug Evans * linux-nat.c (debug_linux_nat_async): Delete. Replace all references to use debug_linux_nat instead. (show_debug_linux_nat_async): Delete. (sigchld_handler): Call ui_file_write_async_safe instead of fprintf_unfiltered. (_initialize_linux_nat): Remove `set debug lin-lwp-async'. * ui-file.c (struct ui_file): New member to_write_async_safe. (null_file_write_async_safe): New function. (ui_file_write_async_safe): New function. (set_ui_file_write_async_safe): New function. (stdio_file_new): Initialize to_write_async_safe. (stdio_file_write_async_safe): New function. * ui-file.h (ui_file_write_async_safe_ftype): New typedef. (set_ui_file_write_async_safe): Declare. (ui_file_write_async_safe): Declare. doc/ * gdb.texinfo (Completion): Update example. Index: linux-nat.c =================================================================== RCS file: /cvs/src/src/gdb/linux-nat.c,v retrieving revision 1.203 diff -u -p -r1.203 linux-nat.c --- linux-nat.c 9 May 2011 18:43:56 -0000 1.203 +++ linux-nat.c 10 May 2011 20:29:30 -0000 @@ -198,16 +198,6 @@ show_debug_linux_nat (struct ui_file *fi value); } -static int debug_linux_nat_async = 0; -static void -show_debug_linux_nat_async (struct ui_file *file, int from_tty, - struct cmd_list_element *c, const char *value) -{ - fprintf_filtered (file, - _("Debugging of GNU/Linux async lwp module is %s.\n"), - value); -} - static int disable_randomization = 1; static void @@ -3260,7 +3250,7 @@ linux_nat_wait_1 (struct target_ops *ops int status = 0; pid_t pid; - if (debug_linux_nat_async) + if (debug_linux_nat) fprintf_unfiltered (gdb_stdlog, "LLW: enter\n"); /* The first time we get here after starting a new inferior, we may @@ -3303,7 +3293,7 @@ retry: { ourstatus->kind = TARGET_WAITKIND_IGNORE; - if (debug_linux_nat_async) + if (debug_linux_nat) fprintf_unfiltered (gdb_stdlog, "LLW: exit (no resumed LWP)\n"); restore_child_signals_mask (&prev_mask); @@ -3546,7 +3536,7 @@ retry: /* No interesting event. */ ourstatus->kind = TARGET_WAITKIND_IGNORE; - if (debug_linux_nat_async) + if (debug_linux_nat) fprintf_unfiltered (gdb_stdlog, "LLW: exit (ignore)\n"); restore_child_signals_mask (&prev_mask); @@ -3561,7 +3551,7 @@ retry: /* No interesting event for PID yet. */ ourstatus->kind = TARGET_WAITKIND_IGNORE; - if (debug_linux_nat_async) + if (debug_linux_nat) fprintf_unfiltered (gdb_stdlog, "LLW: exit (ignore)\n"); restore_child_signals_mask (&prev_mask); @@ -3690,7 +3680,7 @@ retry: else store_waitstatus (ourstatus, status); - if (debug_linux_nat_async) + if (debug_linux_nat) fprintf_unfiltered (gdb_stdlog, "LLW: exit\n"); restore_child_signals_mask (&prev_mask); @@ -5416,8 +5406,9 @@ sigchld_handler (int signo) { int old_errno = errno; - if (debug_linux_nat_async) - fprintf_unfiltered (gdb_stdlog, "sigchld\n"); + if (debug_linux_nat) + ui_file_write_async_safe (gdb_stdlog, + "sigchld\n", sizeof ("sigchld\n") - 1); if (signo == SIGCHLD && linux_nat_event_pipe[0] != -1) @@ -5801,15 +5792,6 @@ Enables printf debugging output."), show_debug_linux_nat, &setdebuglist, &showdebuglist); - add_setshow_zinteger_cmd ("lin-lwp-async", class_maintenance, - &debug_linux_nat_async, _("\ -Set debugging of GNU/Linux async lwp module."), _("\ -Show debugging of GNU/Linux async lwp module."), _("\ -Enables printf debugging output."), - NULL, - show_debug_linux_nat_async, - &setdebuglist, &showdebuglist); - /* Save this mask as the default. */ sigprocmask (SIG_SETMASK, NULL, &normal_mask); Index: ui-file.c =================================================================== RCS file: /cvs/src/src/gdb/ui-file.c,v retrieving revision 1.26 diff -u -p -r1.26 ui-file.c --- ui-file.c 12 Jan 2011 01:23:28 -0000 1.26 +++ ui-file.c 10 May 2011 20:29:30 -0000 @@ -30,6 +30,7 @@ static ui_file_isatty_ftype null_file_isatty; static ui_file_write_ftype null_file_write; +static ui_file_write_ftype null_file_write_async_safe; static ui_file_fputs_ftype null_file_fputs; static ui_file_read_ftype null_file_read; static ui_file_flush_ftype null_file_flush; @@ -42,6 +43,7 @@ struct ui_file int *magic; ui_file_flush_ftype *to_flush; ui_file_write_ftype *to_write; + ui_file_write_async_safe_ftype *to_write_async_safe; ui_file_fputs_ftype *to_fputs; ui_file_read_ftype *to_read; ui_file_delete_ftype *to_delete; @@ -61,6 +63,7 @@ ui_file_new (void) set_ui_file_data (file, NULL, null_file_delete); set_ui_file_flush (file, null_file_flush); set_ui_file_write (file, null_file_write); + set_ui_file_write_async_safe (file, null_file_write_async_safe); set_ui_file_fputs (file, null_file_fputs); set_ui_file_read (file, null_file_read); set_ui_file_isatty (file, null_file_isatty); @@ -155,6 +158,14 @@ null_file_fputs (const char *buf, struct } static void +null_file_write_async_safe (struct ui_file *file, + const char *buf, + long sizeof_buf) +{ + return; +} + +static void null_file_delete (struct ui_file *file) { return; @@ -203,6 +214,14 @@ ui_file_write (struct ui_file *file, file->to_write (file, buf, length_buf); } +void +ui_file_write_async_safe (struct ui_file *file, + const char *buf, + long length_buf) +{ + file->to_write_async_safe (file, buf, length_buf); +} + long ui_file_read (struct ui_file *file, char *buf, long length_buf) { @@ -247,6 +266,13 @@ set_ui_file_write (struct ui_file *file, } void +set_ui_file_write_async_safe (struct ui_file *file, + ui_file_write_async_safe_ftype *write_async_safe) +{ + file->to_write_async_safe = write_async_safe; +} + +void set_ui_file_read (struct ui_file *file, ui_file_read_ftype *read) { file->to_read = read; @@ -437,6 +463,7 @@ mem_file_write (struct ui_file *file, 's FILE. */ static ui_file_write_ftype stdio_file_write; +static ui_file_write_async_safe_ftype stdio_file_write_async_safe; static ui_file_fputs_ftype stdio_file_fputs; static ui_file_read_ftype stdio_file_read; static ui_file_isatty_ftype stdio_file_isatty; @@ -465,6 +492,7 @@ stdio_file_new (FILE *file, int close_p) set_ui_file_data (ui_file, stdio, stdio_file_delete); set_ui_file_flush (ui_file, stdio_file_flush); set_ui_file_write (ui_file, stdio_file_write); + set_ui_file_write_async_safe (ui_file, stdio_file_write_async_safe); set_ui_file_fputs (ui_file, stdio_file_fputs); set_ui_file_read (ui_file, stdio_file_read); set_ui_file_isatty (ui_file, stdio_file_isatty); @@ -536,6 +564,22 @@ stdio_file_write (struct ui_file *file, } static void +stdio_file_write_async_safe (struct ui_file *file, + const char *buf, long length_buf) +{ + struct stdio_file *stdio = ui_file_data (file); + + if (stdio->magic != &stdio_file_magic) + { + const char *msg = _("stdio_file_write_async_safe: bad magic number\n"); + write (2, msg, strlen (msg)); + return; + } + + write (fileno (stdio->file), buf, length_buf); +} + +static void stdio_file_fputs (const char *linebuffer, struct ui_file *file) { struct stdio_file *stdio = ui_file_data (file); Index: ui-file.h =================================================================== RCS file: /cvs/src/src/gdb/ui-file.h,v retrieving revision 1.16 diff -u -p -r1.16 ui-file.h --- ui-file.h 27 Feb 2011 16:25:37 -0000 1.16 +++ ui-file.h 10 May 2011 20:29:30 -0000 @@ -45,6 +45,17 @@ typedef void (ui_file_fputs_ftype) (cons extern void set_ui_file_fputs (struct ui_file *stream, ui_file_fputs_ftype *fputs); +/* This version of "write" is safe for use in signal handlers. + It's not guaranteed that all existing output will have been + flushed first. + Implementations are also free to ignore some or all of the request. + fputs_async is not provided as the async versions are rarely used, + no point in having both for a rarely used interface. */ +typedef void (ui_file_write_async_safe_ftype) + (struct ui_file *stream, const char *buf, long length_buf); +extern void set_ui_file_write_async_safe + (struct ui_file *stream, ui_file_write_async_safe_ftype *write_async_safe); + typedef long (ui_file_read_ftype) (struct ui_file *stream, char *buf, long length_buf); extern void set_ui_file_read (struct ui_file *stream, @@ -83,6 +94,9 @@ extern int ui_file_isatty (struct ui_fil extern void ui_file_write (struct ui_file *file, const char *buf, long length_buf); +extern void ui_file_write_async_safe (struct ui_file *file, const char *buf, + long length_buf); + /* NOTE: copies left to right. */ extern void ui_file_put (struct ui_file *src, ui_file_put_method_ftype *write, void *dest); Index: doc/gdb.texinfo =================================================================== RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v retrieving revision 1.832 diff -u -p -r1.832 gdb.texinfo --- doc/gdb.texinfo 10 May 2011 16:53:22 -0000 1.832 +++ doc/gdb.texinfo 10 May 2011 20:29:31 -0000 @@ -1592,8 +1592,10 @@ left-hand-side: @smallexample (@value{GDBP}) p gdb_stdout.@kbd{M-?} -magic to_delete to_fputs to_put to_rewind -to_data to_flush to_isatty to_read to_write +magic to_fputs to_rewind +to_data to_isatty to_write +to_delete to_put to_write_async_safe +to_flush to_read @end smallexample @noindent @@ -1607,6 +1609,7 @@ struct ui_file int *magic; ui_file_flush_ftype *to_flush; ui_file_write_ftype *to_write; + ui_file_write_async_safe_ftype *to_write_async_safe; ui_file_fputs_ftype *to_fputs; ui_file_read_ftype *to_read; ui_file_delete_ftype *to_delete;