From fde1a9a3ee8c95bb7bae6c764755bcbffdbb0308 Mon Sep 17 00:00:00 2001 From: Andrew Burgess Date: Thu, 26 Apr 2018 16:21:34 +0100 Subject: [PATCH] gdb: add setting to disable reading source code files In some situations it is possible that a user might not want GDB to try and access source code files, for example, the source code might be stored on a slow to access network file system. It is almost certainly possible that using some combination of 'set directories' and/or 'set substitute-path' a user can trick GDB into being unable to find the source files, but this feels like a rather crude way to solve the problem. In this commit a new option is add that stops GDB from opening and reading the source files. A user can run with source code reading disabled if this is required, then re-enable later if they decide that they now want to view the source code. --- gdb/NEWS | 9 ++++ gdb/cli/cli-cmds.c | 4 ++ gdb/cli/cli-cmds.h | 8 ++++ gdb/doc/gdb.texinfo | 26 ++++++++++ gdb/source.c | 66 ++++++++++++++++++++++++-- gdb/testsuite/gdb.base/source-open.c | 25 ++++++++++ gdb/testsuite/gdb.base/source-open.exp | 44 +++++++++++++++++ 7 files changed, 179 insertions(+), 3 deletions(-) create mode 100644 gdb/testsuite/gdb.base/source-open.c create mode 100644 gdb/testsuite/gdb.base/source-open.exp diff --git a/gdb/NEWS b/gdb/NEWS index f9485520438..d7c29c82edb 100644 --- a/gdb/NEWS +++ b/gdb/NEWS @@ -3,6 +3,8 @@ *** Changes since GDB 11 +* New commands + maint set backtrace-on-fatal-signal on|off maint show backtrace-on-fatal-signal This setting is 'on' by default. When 'on' GDB will print a limited @@ -10,6 +12,13 @@ maint show backtrace-on-fatal-signal fatal signal. This only supported on some platforms where the backtrace and backtrace_symbols_fd functions are available. +set source open on|off +show source open + This setting, which is on by default, controls whether GDB will try + to open source code files. Switching this off will stop GDB trying + to open and read source code files, which can be useful if the files + are located over a slow network connection. + * Python API ** New function gdb.add_history(), which takes a gdb.Value object diff --git a/gdb/cli/cli-cmds.c b/gdb/cli/cli-cmds.c index 5ff0b77eb68..e5c7152ba7a 100644 --- a/gdb/cli/cli-cmds.c +++ b/gdb/cli/cli-cmds.c @@ -168,6 +168,10 @@ struct cmd_list_element *setchecklist; struct cmd_list_element *showchecklist; +struct cmd_list_element *setsourcelist; + +struct cmd_list_element *showsourcelist; + /* Command tracing state. */ int source_verbose = 0; diff --git a/gdb/cli/cli-cmds.h b/gdb/cli/cli-cmds.h index ce2e38886f1..a4b4168896e 100644 --- a/gdb/cli/cli-cmds.h +++ b/gdb/cli/cli-cmds.h @@ -137,6 +137,14 @@ extern struct cmd_list_element *showchecklist; extern struct cmd_list_element *save_cmdlist; +/* Chain containing all defined "set source" subcommands. */ + +extern struct cmd_list_element *setsourcelist; + +/* Chain containing all defined "show source" subcommands. */ + +extern struct cmd_list_element *showsourcelist; + /* Limit the call depth of user-defined commands */ extern unsigned int max_user_call_depth; diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo index bf731a1feb5..fcfdc26ac1a 100644 --- a/gdb/doc/gdb.texinfo +++ b/gdb/doc/gdb.texinfo @@ -8919,6 +8919,7 @@ prefer to use Emacs facilities to view source; see @ref{Emacs, ,Using * Search:: Searching source files * Source Path:: Specifying source directories * Machine Code:: Source and machine code +* Disable Reading Source:: Disable Reading Source Code @end menu @node List @@ -9926,6 +9927,31 @@ OFF, which means never display the disassembly of the next line or instruction. @end table +@node Disable Reading Source +@section Disable Reading Source Code +@cindex source code, disable access + +In some cases it can be desirable to prevent @value{GDBN} from +accessing source code files. One case where this might be desirable +is if the source code files are located over a slow network +connection. + +The following command can be used to control whether @value{GDBN} +should access source code files or not: + +@table @code +@kindex set source open +@kindex show source open +@item set source open @r{[}on@r{|}off@r{]} +@itemx show source open +When this option is @code{on}, which is the default, @value{GDBN} will +access source code files when needed, for example to print source +lines when @value{GDBN} stops, or in response to the @code{list} +command. + +When this option is @code{off}, @value{GDBN} will not access source +code files. +@end table @node Data @chapter Examining Data diff --git a/gdb/source.c b/gdb/source.c index 7d1934bd6c9..eec6e77eaa3 100644 --- a/gdb/source.c +++ b/gdb/source.c @@ -148,7 +148,21 @@ show_filename_display_string (struct ui_file *file, int from_tty, { fprintf_filtered (file, _("Filenames are displayed as \"%s\".\n"), value); } - + +/* When true GDB will stat and open source files as required, but when + false, GDB will avoid accessing source files as much as possible. */ + +static bool source_open = true; + +/* Implement 'show source open'. */ + +static void +show_source_open (struct ui_file *file, int from_tty, + struct cmd_list_element *c, const char *value) +{ + fprintf_filtered (file, _("Source opening is \"%s\".\n"), value); +} + /* Line number of last line printed. Default for various commands. current_source_line is usually, but not always, the same as this. */ @@ -1048,8 +1062,13 @@ find_and_open_source (const char *filename, const char *p; int result; - /* Quick way out if we already know its full name. */ + /* If reading of source files is disabled then return a result indicating + the attempt to read this source file failed. GDB will then display + the filename and line number instead. */ + if (!source_open) + return scoped_fd (-1); + /* Quick way out if we already know its full name. */ if (*fullname) { /* The user may have requested that source paths be rewritten @@ -1062,6 +1081,7 @@ find_and_open_source (const char *filename, *fullname = std::move (rewritten_fullname); result = gdb_open_cloexec (fullname->get (), OPEN_MODE, 0); + if (result >= 0) { *fullname = gdb_realpath (fullname->get ()); @@ -1300,7 +1320,7 @@ print_source_lines_base (struct symtab *s, int line, int stopline, /* If printing of source lines is disabled, just print file and line number. */ - if (uiout->test_flags (ui_source_list)) + if (uiout->test_flags (ui_source_list) && source_open) { /* Only prints "No such file or directory" once. */ if (s == last_source_visited) @@ -1603,6 +1623,9 @@ search_command_helper (const char *regex, int from_tty, bool forward) if (loc->symtab () == nullptr) select_source_symtab (0); + if (!source_open) + error (_("source code access disabled")); + scoped_fd desc (open_source_file (loc->symtab ())); if (desc.get () < 0) perror_with_name (symtab_to_filename_for_display (loc->symtab ())); @@ -1927,6 +1950,22 @@ source_lines_range::source_lines_range (int startline, } } +/* Handle the "set source" base command. */ + +static void +set_source (const char *arg, int from_tty) +{ + help_list (setsourcelist, "set source ", all_commands, gdb_stdout); +} + +/* Handle the "show source" base command. */ + +static void +show_source (const char *args, int from_tty) +{ + help_list (showsourcelist, "show source ", all_commands, gdb_stdout); +} + void _initialize_source (); void @@ -2050,4 +2089,25 @@ By default, relative filenames are displayed."), show_filename_display_string, &setlist, &showlist); + add_prefix_cmd ("source", no_class, set_source, + _("Generic command for setting how sources are handled."), + &setsourcelist, 0, &setlist); + + add_prefix_cmd ("source", no_class, show_source, + _("Generic command for showing source settings."), + &showsourcelist, 0, &showlist); + + add_setshow_boolean_cmd ("open", class_files, &source_open, _("\ +Set whether GDB should open source files."), _("\ +Show whether GDB should open source files."), _("\ +When this option is on GDB will open source files and display the\n\ +contents when appropriate, for example, when GDB stops, or the list\n\ +command is used.\n\ +When this option is off GDB will not try to open source files, instead\n\ +GDB will print the file and line number that would have been displayed.\n\ +This can be useful if access to source code files is slow, for example\n\ +due to the source being located over a slow network connection."), + NULL, + show_source_open, + &setsourcelist, &showsourcelist); } diff --git a/gdb/testsuite/gdb.base/source-open.c b/gdb/testsuite/gdb.base/source-open.c new file mode 100644 index 00000000000..1fb5edb9e75 --- /dev/null +++ b/gdb/testsuite/gdb.base/source-open.c @@ -0,0 +1,25 @@ +/* This testcase is part of GDB, the GNU debugger. + + Copyright 2021 Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . */ + +#include + +int +main (int argc, char* argv[]) +{ + printf ("source code line."); + return 0; +} diff --git a/gdb/testsuite/gdb.base/source-open.exp b/gdb/testsuite/gdb.base/source-open.exp new file mode 100644 index 00000000000..eb801427bf3 --- /dev/null +++ b/gdb/testsuite/gdb.base/source-open.exp @@ -0,0 +1,44 @@ +# Copyright 2021 Free Software Foundation, Inc. + +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 3 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +# Test the 'set source open on|off' command. + +standard_testfile + +if {[prepare_for_testing "failed to prepare" $testfile $srcfile debug]} { + return -1 +} + +gdb_test "show source open" "Source opening is \"on\"\\." \ + "source opening is initially on" +gdb_test_no_output "set listsize 1" +gdb_test_no_output "set source open on" +gdb_test "list 18" "18\t#include " "source reading on" + +# File opening is turned off therefore source lines are not printed. +gdb_test_no_output "set source open off" +gdb_test "show source open" "Source opening is \"off\"\\." \ + "source opening is now off" +gdb_test "list 18" "18\tin .*/${srcfile}" "source reading off" + +gdb_test "forward-search main" "source code access disabled" +gdb_test "reverse-search main" "source code access disabled" + +# And finally, turn source code reading back on. +gdb_test_no_output "set source open on" \ + "turn source reading back on" +gdb_test "show source open" "Source opening is \"on\"\\." \ + "source opening is on again" +gdb_test "list 18" "18\t#include " "source reading on again" -- 2.30.2