From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from simark.ca by simark.ca with LMTP id RGl6DnJ/+F+YMgAAWB0awg (envelope-from ) for ; Fri, 08 Jan 2021 10:51:14 -0500 Received: by simark.ca (Postfix, from userid 112) id 2CE791E99A; Fri, 8 Jan 2021 10:51:14 -0500 (EST) X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on simark.ca X-Spam-Level: X-Spam-Status: No, score=-1.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.2 Received: from sourceware.org (server2.sourceware.org [8.43.85.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by simark.ca (Postfix) with ESMTPS id A26D91E4F4 for ; Fri, 8 Jan 2021 10:51:12 -0500 (EST) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 42774384B823; Fri, 8 Jan 2021 15:51:12 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 42774384B823 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1610121072; bh=wZc9CViwcdDlzIqBk0wkCSAoZB8ffDdoFU2jSSGLBs0=; h=Subject:To:References:Date:In-Reply-To:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=jGz3yL/b1/U8Y3+c0qacoisNUUNOM0DBBYyVB2jmda9iD04yStJf5mNcFezB18KBh MqwPQPYQwhHKmX5+MVpLZqC597RQ6tru/lxxJfmgXTfv4OGbngo/2AsdbCEZIs4RVu dYjst742ZEOcm7ngCO9AmzrOMPSNBNz/82okHD5g= Received: from smtp.polymtl.ca (smtp.polymtl.ca [132.207.4.11]) by sourceware.org (Postfix) with ESMTPS id AC17A384B822 for ; Fri, 8 Jan 2021 15:51:09 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org AC17A384B822 Received: from simark.ca (simark.ca [158.69.221.121]) (authenticated bits=0) by smtp.polymtl.ca (8.14.7/8.14.7) with ESMTP id 108Foxjw021283 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 8 Jan 2021 10:51:04 -0500 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp.polymtl.ca 108Foxjw021283 Received: from [10.0.0.213] (192-222-157-6.qc.cable.ebox.net [192.222.157.6]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by simark.ca (Postfix) with ESMTPSA id AA2C51E4F4; Fri, 8 Jan 2021 10:50:58 -0500 (EST) Subject: [PATCH v2] gdb: check for empty strings in, get_standard_cache_dir/get_standard_config_dir To: Andrew Burgess , Simon Marchi References: <20210107205725.2010353-1-simon.marchi@efficios.com> <20210108094811.GT2945@embecosm.com> Message-ID: <0ddb71dd-8ff8-ae3b-09bd-96ba46bfdaf1@polymtl.ca> Date: Fri, 8 Jan 2021 10:50:58 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <20210108094811.GT2945@embecosm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Poly-FromMTA: (simark.ca [158.69.221.121]) at Fri, 8 Jan 2021 15:50:59 +0000 X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Simon Marchi via Gdb-patches Reply-To: Simon Marchi Cc: gdb-patches@sourceware.org, sourcewarebugz@kyber.fi Errors-To: gdb-patches-bounces@sourceware.org Sender: "Gdb-patches" On 2021-01-08 4:48 a.m., Andrew Burgess wrote: > I wonder if it's worth including the case where ALL of the environment > variables are empty as well, just to check that there's no issues with > GDB falling through all the checks? I don't know, but it wasn't too difficult so I did it. > > Otherwise, LGTM. I also thought it would be a good idea to check that the index-cache directory value doesn't get affected by these empty values, that we properly skip over them. See updated patch below. >From c010770be40c91b97be5e97ce830abea4efd8f86 Mon Sep 17 00:00:00 2001 From: Simon Marchi Date: Fri, 8 Jan 2021 10:47:53 -0500 Subject: [PATCH v2] gdb: check for empty strings in get_standard_cache_dir/get_standard_config_dir New in v2: - Check the value of the index-cache directory before and after. - Check with all the env vars defined to empty. As reported in PR 27157, if some environment variables read at startup by GDB are defined but empty, we hit the assert in gdb_abspath: $ XDG_CACHE_HOME= ./gdb -nx --data-directory=data-directory -q AddressSanitizer:DEADLYSIGNAL ================================================================= ==2007040==ERROR: AddressSanitizer: SEGV on unknown address 0x0000000001b0 (pc 0x5639d4aa4127 bp 0x7ffdac232c00 sp 0x7ffdac232bf0 T0) ==2007040==The signal is caused by a READ memory access. ==2007040==Hint: address points to the zero page. #0 0x5639d4aa4126 in target_stack::top() const /home/smarchi/src/binutils-gdb/gdb/target.h:1334 #1 0x5639d4aa41f1 in inferior::top_target() /home/smarchi/src/binutils-gdb/gdb/inferior.h:369 #2 0x5639d4a70b1f in current_top_target() /home/smarchi/src/binutils-gdb/gdb/target.c:120 #3 0x5639d4b00591 in gdb_readline_wrapper_cleanup::gdb_readline_wrapper_cleanup() /home/smarchi/src/binutils-gdb/gdb/top.c:1046 #4 0x5639d4afab31 in gdb_readline_wrapper(char const*) /home/smarchi/src/binutils-gdb/gdb/top.c:1104 #5 0x5639d4ccce2c in defaulted_query /home/smarchi/src/binutils-gdb/gdb/utils.c:893 #6 0x5639d4ccd6af in query(char const*, ...) /home/smarchi/src/binutils-gdb/gdb/utils.c:985 #7 0x5639d4ccaec1 in internal_vproblem /home/smarchi/src/binutils-gdb/gdb/utils.c:373 #8 0x5639d4ccb3d1 in internal_verror(char const*, int, char const*, __va_list_tag*) /home/smarchi/src/binutils-gdb/gdb/utils.c:439 #9 0x5639d5151a92 in internal_error(char const*, int, char const*, ...) /home/smarchi/src/binutils-gdb/gdbsupport/errors.cc:55 #10 0x5639d5162ab4 in gdb_abspath(char const*) /home/smarchi/src/binutils-gdb/gdbsupport/pathstuff.cc:132 #11 0x5639d5162fac in get_standard_cache_dir[abi:cxx11]() /home/smarchi/src/binutils-gdb/gdbsupport/pathstuff.cc:228 #12 0x5639d3e76a81 in _initialize_index_cache() /home/smarchi/src/binutils-gdb/gdb/dwarf2/index-cache.c:325 #13 0x5639d4dbbe92 in initialize_all_files() /home/smarchi/build/binutils-gdb/gdb/init.c:321 #14 0x5639d4b00259 in gdb_init(char*) /home/smarchi/src/binutils-gdb/gdb/top.c:2344 #15 0x5639d4440715 in captured_main_1 /home/smarchi/src/binutils-gdb/gdb/main.c:950 #16 0x5639d444252e in captured_main /home/smarchi/src/binutils-gdb/gdb/main.c:1229 #17 0x5639d44425cf in gdb_main(captured_main_args*) /home/smarchi/src/binutils-gdb/gdb/main.c:1254 #18 0x5639d3923371 in main /home/smarchi/src/binutils-gdb/gdb/gdb.c:32 #19 0x7fa002d3f0b2 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x270b2) #20 0x5639d392314d in _start (/home/smarchi/build/binutils-gdb/gdb/gdb+0x4d414d) gdb_abspath doesn't handle empty strings, so handle this case in the callers. If a variable is defined but empty, I think it's reasonable in this case to just ignore it, as if it was not defined. Note that this sometimes also lead to a segfault, because the failed assertion happens very early during startup, before things are fully initialized. gdbsupport/ChangeLog: PR gdb/27157 * pathstuff.cc (get_standard_cache_dir, get_standard_config_dir, find_gdb_home_config_file): Add empty string check. gdb/testsuite/ChangeLog: PR gdb/27157 * gdb.base/empty-host-env-vars.exp: New test. Change-Id: I8654d8e97e74e1dff6d308c111ae4b1bbf07bef9 --- .../gdb.base/empty-host-env-vars.exp | 72 +++++++++++++++++++ gdbsupport/pathstuff.cc | 14 ++-- 2 files changed, 79 insertions(+), 7 deletions(-) create mode 100644 gdb/testsuite/gdb.base/empty-host-env-vars.exp diff --git a/gdb/testsuite/gdb.base/empty-host-env-vars.exp b/gdb/testsuite/gdb.base/empty-host-env-vars.exp new file mode 100644 index 000000000000..bd7212e7b655 --- /dev/null +++ b/gdb/testsuite/gdb.base/empty-host-env-vars.exp @@ -0,0 +1,72 @@ +# 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 . + +# GDB reads some environment variables on startup, make sure it behaves +# correctly if these variables are defined but empty. + +set all_env_vars { HOME XDG_CACHE_HOME LOCALAPPDATA XDG_CONFIG_HOME } + +# Record the initial value of the index-cache directory. +clean_restart +set index_cache_directory "" +gdb_test_multiple "show index-cache directory" "" { + -re -wrap "The directory of the index cache is \"(.*)\"\\." { + set index_cache_directory $expect_out(1,string) + set index_cache_directory [string_to_regexp $index_cache_directory] + pass $gdb_test_name + } +} + +foreach_with_prefix env_var_name $all_env_vars { + # Restore the original state of the environment variable. + save_vars env($env_var_name) { + set env($env_var_name) {} + clean_restart + + # Verify that the empty environment variable didn't affect the + # index-cache directory setting, that we still see the initial value. + # "HOME" is different, because if that one is unset, GDB isn't even + # able to compute the default location. In that case, we expect it to + # be empty. + if { $env_var_name == "HOME" } { + gdb_test "show index-cache directory" \ + "The directory of the index cache is \"\"\\." + } else { + gdb_test "show index-cache directory" \ + "The directory of the index cache is \"$index_cache_directory\"\\." + } + } +} + +# Try the same, but with all the env vars set to an empty value at the same +# time. +with_test_prefix "all env vars" { + set save_vars_arg {} + foreach env_var_name $all_env_vars { + lappend save_vars_arg env($env_var_name) + } + + # Restore the original state of all the environment variables. + save_vars $save_vars_arg { + foreach env_var_name $all_env_vars { + set env($env_var_name) {} + } + + clean_restart + + gdb_test "show index-cache directory" \ + "The directory of the index cache is \"\"\\." + } +} diff --git a/gdbsupport/pathstuff.cc b/gdbsupport/pathstuff.cc index 51ab8c651b20..ad13900819ef 100644 --- a/gdbsupport/pathstuff.cc +++ b/gdbsupport/pathstuff.cc @@ -222,7 +222,7 @@ get_standard_cache_dir () #ifndef __APPLE__ const char *xdg_cache_home = getenv ("XDG_CACHE_HOME"); - if (xdg_cache_home != NULL) + if (xdg_cache_home != NULL && xdg_cache_home[0] != '\0') { /* Make sure the path is absolute and tilde-expanded. */ gdb::unique_xmalloc_ptr abs (gdb_abspath (xdg_cache_home)); @@ -231,7 +231,7 @@ get_standard_cache_dir () #endif const char *home = getenv ("HOME"); - if (home != NULL) + if (home != NULL && home[0] != '\0') { /* Make sure the path is absolute and tilde-expanded. */ gdb::unique_xmalloc_ptr abs (gdb_abspath (home)); @@ -240,14 +240,14 @@ get_standard_cache_dir () #ifdef WIN32 const char *win_home = getenv ("LOCALAPPDATA"); - if (win_home != NULL) + if (win_home != NULL && win_home[0] != '\0') { /* Make sure the path is absolute and tilde-expanded. */ gdb::unique_xmalloc_ptr abs (gdb_abspath (win_home)); return string_printf ("%s/gdb", abs.get ()); } #endif - + return {}; } @@ -289,7 +289,7 @@ get_standard_config_dir () #ifndef __APPLE__ const char *xdg_config_home = getenv ("XDG_CONFIG_HOME"); - if (xdg_config_home != NULL) + if (xdg_config_home != NULL && xdg_config_home[0] != '\0') { /* Make sure the path is absolute and tilde-expanded. */ gdb::unique_xmalloc_ptr abs (gdb_abspath (xdg_config_home)); @@ -298,7 +298,7 @@ get_standard_config_dir () #endif const char *home = getenv ("HOME"); - if (home != NULL) + if (home != NULL && home[0] != '\0') { /* Make sure the path is absolute and tilde-expanded. */ gdb::unique_xmalloc_ptr abs (gdb_abspath (home)); @@ -340,7 +340,7 @@ find_gdb_home_config_file (const char *name, struct stat *buf) } const char *homedir = getenv ("HOME"); - if (homedir != nullptr) + if (homedir != nullptr && homedir[0] != '\0') { /* Make sure the path is absolute and tilde-expanded. */ gdb::unique_xmalloc_ptr abs (gdb_abspath (homedir)); -- 2.29.2