From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-1.mimecast.com (us-smtp-delivery-1.mimecast.com [205.139.110.120]) by sourceware.org (Postfix) with ESMTP id 87B5C3953CE9 for ; Tue, 19 May 2020 19:37:26 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 87B5C3953CE9 Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-138-HnxyqHfVMNO104U_BBkBGw-1; Tue, 19 May 2020 15:37:25 -0400 X-MC-Unique: HnxyqHfVMNO104U_BBkBGw-1 Received: by mail-wm1-f69.google.com with SMTP id t62so131816wmt.7 for ; Tue, 19 May 2020 12:37:24 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=g7viAZvJxqdpbRrD5WNSC7DC7/ck+IDtpCJ00Oh8uKs=; b=kBJDf1gYkBpJM0Sq7Ts7iVnvq5BFrllNeCSIYTtWe9JvyxWLytBJE3qIXbY9+xOn2a ETPUmD+N5jt05IvFY1KFejl759GQyP3I2w10rvLSt6Vm2MRk7NoEJyimXtl60vt2i9SI aig0TDKGNtnUSqr/jxqiYGitgx+QQ8JaxlS6VXRqlzfHJAZuB7nMmR3dB/pQ8Zpkf9Z1 BtEoviIbMkeS/8bfJvbsfYev5/i4PE2+QXgTuZPNWwfEDRE4oFZ/ezzTKYiSUgd/fI8F fAoJnLJYUKH7YqI4bUUzJtHkBGnEh6xfvxW6jidJaY67Nxr75dKfXA5BtNp7Q5MTw5RK SAVg== X-Gm-Message-State: AOAM533xbMeagVk0fIiTqjQuvmIVV+jTaU5oIaPZfWs4h3SVWaX/hsf/ Mddw6i0T1qRhRMu9L98RX3iwTkzfZmaMnOj0fh82gIdMgAQHkoaoBAt+Ig/wZK3FTbV8rHZwdsy xzafs2NqQP0UkigYM3Drang== X-Received: by 2002:adf:ec45:: with SMTP id w5mr525192wrn.96.1589917043315; Tue, 19 May 2020 12:37:23 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwqYto/URw0eOkMKjO5krgdc40ZKn/b2+AGHTk4iDh/8inrcyL4HcMqE+uHkF0GVY5ADu0cLA== X-Received: by 2002:adf:ec45:: with SMTP id w5mr525183wrn.96.1589917043147; Tue, 19 May 2020 12:37:23 -0700 (PDT) Received: from ?IPv6:2001:8a0:f909:7b00:56ee:75ff:fe8d:232b? ([2001:8a0:f909:7b00:56ee:75ff:fe8d:232b]) by smtp.gmail.com with ESMTPSA id 10sm744060wmw.26.2020.05.19.12.37.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 19 May 2020 12:37:22 -0700 (PDT) Subject: Re: PR25993, read of freed memory To: Simon Marchi , Alan Modra , binutils@sourceware.org, gdb-patches@sourceware.org References: <20200519043205.GT1088@bubble.grove.modra.org> <111d8c5d-d615-e0ae-36de-519c43a51139@simark.ca> From: Pedro Alves Message-ID: <5dd5a430-dff4-fd16-4cd1-126171ee6507@redhat.com> Date: Tue, 19 May 2020 20:37:21 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <111d8c5d-d615-e0ae-36de-519c43a51139@simark.ca> Content-Language: en-US X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-4.1 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=unavailable autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org 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: , X-List-Received-Date: Tue, 19 May 2020 19:37:27 -0000 On 5/19/20 2:27 PM, Simon Marchi wrote: > It now doesn't really make sense for symbol_file_add_from_memory to accept a malloc-ed > string (the point was that before we gave ownership of that malloc-ed string to bfd). > > Can you please change `char *name` to be `gdb::optional`? > > The caller that passes a name should use string_printf to build the string, as mentioned > above. The caller that does not pass a name can pass `{}`, to pass an empty optional. Wouldn't 'const char * or NULL' work? Seems way simpler to me. > > The `if (name == NULL)` would become something like: > > if (!name.has_value ()) > name.emplace ("shared object read from target memory"); > This would just be if (name == NULL) name = "shared object read from target memory"; > And then: > > bfd_set_filename (nbfd, name->c_str ()); Thanks, Pedro Alves