From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 27930 invoked by alias); 23 Apr 2009 08:06:07 -0000 Received: (qmail 27921 invoked by uid 22791); 23 Apr 2009 08:06:06 -0000 X-SWARE-Spam-Status: No, hits=-1.6 required=5.0 tests=AWL,BAYES_00,SARE_MSGID_LONG40,SPF_PASS X-Spam-Check-By: sourceware.org Received: from ti-out-0910.google.com (HELO ti-out-0910.google.com) (209.85.142.191) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 23 Apr 2009 08:06:00 +0000 Received: by ti-out-0910.google.com with SMTP id a1so60807tib.12 for ; Thu, 23 Apr 2009 01:05:58 -0700 (PDT) MIME-Version: 1.0 Received: by 10.110.43.20 with SMTP id q20mr65969tiq.15.1240473958165; Thu, 23 Apr 2009 01:05:58 -0700 (PDT) In-Reply-To: <8ac60eac0904230001w1afd9179wcb76e1cfd7f3f386@mail.gmail.com> References: <1239225742.8871.145.camel@localhost.localdomain> <8ac60eac0904200947y2acca97arc1a0fc61530357a0@mail.gmail.com> <20090420170154.GA10112@caradoc.them.org> <8ac60eac0904201019g7ba8056bx5e84e6bfdf5935d8@mail.gmail.com> <20090420180352.GA14206@caradoc.them.org> <8ac60eac0904201208m95d4585k2b09f6b6fe5edb40@mail.gmail.com> <20090422172517.GA17235@caradoc.them.org> <8ac60eac0904221810x24763ecaj4a888927b766e7f7@mail.gmail.com> <8ac60eac0904230001w1afd9179wcb76e1cfd7f3f386@mail.gmail.com> Date: Thu, 23 Apr 2009 08:06:00 -0000 Message-ID: Subject: Re: [patch][rfc] Allow GDB to search for the right libthread_db.so.1 From: Hui Zhu To: Paul Pluzhnikov Cc: tromey@redhat.com, Thiago Jung Bauermann , gdb-patches ml , Eli Zaretskii Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit 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: 2009-04/txt/msg00640.txt.bz2 On Thu, Apr 23, 2009 at 15:01, Paul Pluzhnikov wrote: > On Wed, Apr 22, 2009 at 11:21 PM, Hui Zhu wrote: > >> About your patch, I think let user choice load which libthread_db is >> very cool idea. >> Why not let they set which file they want to load directly? >> >> For example: >> set libthread-db /xxx_dir/libxxx > > As I stated at the start of this thread, we have a mixture of > executables: some are linked statically, some dynamically, and > against several (incompatible WRT libthread_db) glibc versions. > > I'd like GDB to work "automagically" for all such executables, > without the end user having to understand and specify exactly > which libthread_db must be loaded for each one [1]. > > The patch allows me to achieve that (all I need to do is provide > appropriate local definition of LIBTHREAD_DB_SEARCH_PATH). > > [1] Understanding this requires the user to understand how > GDB uses libthread_db and the relationship between libpthread and > libthread_db. Also, the mapping is complicated by the fact that > 64-bit GDB is sometimes used to debug 32-bit inferiors. > I read your patch again, And I think let user set file name is not conflict with your patch. In thread_db_load_search: + while (*search_path) + { + const char *end = strchr (search_path, ':'); + if (end) + { + size_t len = end - search_path; + if (len + 1 + strlen (LIBTHREAD_DB_SO) + 1 > sizeof (path)) + { + char *cp = xmalloc (len + 1); + memcpy (cp, search_path, len); + cp[len] = '\0'; + warning (_("libthread_db_search_path component too long," + " ignored: %s."), cp); + xfree (cp); + search_path += len + 1; + continue; + } + memcpy (path, search_path, len); + path[len] = '\0'; + search_path += len + 1; + } + else + { + size_t len = strlen (search_path); + + if (len + 1 + strlen (LIBTHREAD_DB_SO) + 1 > sizeof (path)) + { + warning (_("libthread_db_search_path component too long," + " ignored: %s."), search_path); + break; + } + memcpy (path, search_path, len + 1); + search_path += len; + } When you get a path, you can check if this is a directory. If this is a directory, do following job. + strcat (path, "/"); + strcat (path, LIBTHREAD_DB_SO); + if (try_thread_db_load (path)) + { + rc = 1; + break; + } If this is a normal file, try_thread_db_load (path) without strcat LIBTHREAD_DB_SO. What do you think about it? And in thread_db_load: + msym = lookup_minimal_symbol ("nptl_version", NULL, NULL); + if (!msym) + msym = lookup_minimal_symbol ("__linuxthreads_version", NULL, NULL); + + /* Some really old libpthread versions do not have either of the above. */ + if (!msym) + msym = lookup_minimal_symbol ("__pthread_threads_events", NULL, NULL); + + if (!msym) + /* No threads yet */ + return 0; You really don't want gdb try it with libthread_db? If in the future, this code doesn't cover everything. And I think let gdb try will not affect anything. :) Thanks, Hui