From patchwork Tue Jul 6 18:09:20 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Siddhesh Poyarekar X-Patchwork-Id: 44189 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 33F9138930ED for ; Tue, 6 Jul 2021 18:13:23 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 33F9138930ED DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1625595203; bh=AaxEIeRgte+fwzU0PjkWiMOp8avVlaQZFeJszzKpZy8=; h=To:Subject:Date:In-Reply-To:References:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=OmJ+AGCOpjgNshL/gNH1PK76bXfd3+V3BgYg/sBHSRixg9+CHuuE+98sp5X7ba8tO ej+nNO9lVXGB8vNtCxm52Udad/k/FRuoYSQR/Yr1nKVQvJNFiisPFuqRIFSyUDrJfX PzeyigEXVT4MqDOvsEgg8RVLggow/Nsh8lr0s6W0= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from insect.birch.relay.mailchannels.net (insect.birch.relay.mailchannels.net [23.83.209.93]) by sourceware.org (Postfix) with ESMTPS id 507AE3891C30 for ; Tue, 6 Jul 2021 18:10:01 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 507AE3891C30 X-Sender-Id: dreamhost|x-authsender|siddhesh@gotplt.org Received: from relay.mailchannels.net (localhost [127.0.0.1]) by relay.mailchannels.net (Postfix) with ESMTP id 1D23A922A3A; Tue, 6 Jul 2021 18:10:00 +0000 (UTC) Received: from pdx1-sub0-mail-a29.g.dreamhost.com (100-96-133-119.trex-nlb.outbound.svc.cluster.local [100.96.133.119]) (Authenticated sender: dreamhost) by relay.mailchannels.net (Postfix) with ESMTPA id 64363922845; Tue, 6 Jul 2021 18:09:59 +0000 (UTC) X-Sender-Id: dreamhost|x-authsender|siddhesh@gotplt.org Received: from pdx1-sub0-mail-a29.g.dreamhost.com (pop.dreamhost.com [64.90.62.162]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384) by 100.96.133.119 (trex/6.3.3); Tue, 06 Jul 2021 18:10:00 +0000 X-MC-Relay: Neutral X-MailChannels-SenderId: dreamhost|x-authsender|siddhesh@gotplt.org X-MailChannels-Auth-Id: dreamhost X-Zesty-Hysterical: 5904296f78c7ba38_1625594999966_1203285316 X-MC-Loop-Signature: 1625594999966:3267239809 X-MC-Ingress-Time: 1625594999965 Received: from pdx1-sub0-mail-a29.g.dreamhost.com (localhost [127.0.0.1]) by pdx1-sub0-mail-a29.g.dreamhost.com (Postfix) with ESMTP id 1BEAF7EC6B; Tue, 6 Jul 2021 11:09:59 -0700 (PDT) Received: from rhbox.intra.reserved-bit.com (unknown [1.186.101.110]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: siddhesh@gotplt.org) by pdx1-sub0-mail-a29.g.dreamhost.com (Postfix) with ESMTPSA id BC26E7E6C2; Tue, 6 Jul 2021 11:09:55 -0700 (PDT) X-DH-BACKEND: pdx1-sub0-mail-a29 To: libc-alpha@sourceware.org Subject: [PATCH v6 4/8] mtrace: Wean away from malloc hooks Date: Tue, 6 Jul 2021 23:39:20 +0530 Message-Id: <20210706180924.95047-5-siddhesh@sourceware.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210706180924.95047-1-siddhesh@sourceware.org> References: <20210706180924.95047-1-siddhesh@sourceware.org> MIME-Version: 1.0 X-Spam-Status: No, score=-3493.6 required=5.0 tests=BAYES_00, GIT_PATCH_0, JMQ_SPF_NEUTRAL, KAM_DMARC_NONE, KAM_DMARC_STATUS, KAM_SHORT, RCVD_IN_BARRACUDACENTRAL, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_NEUTRAL, TXREP, URIBL_BLACK autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Siddhesh Poyarekar via Libc-alpha From: Siddhesh Poyarekar Reply-To: Siddhesh Poyarekar Cc: fweimer@redhat.com Errors-To: libc-alpha-bounces+patchwork=sourceware.org@sourceware.org Sender: "Libc-alpha" Wean mtrace away from the malloc hooks and move them into the debug DSO. Split the API away from the implementation so that we can add the API to libc.so as well as libc_malloc_debug.so, with the libc implementations being empty. --- malloc/malloc-debug.c | 13 ++ malloc/mtrace-impl.c | 224 ++++++++++++++++++++++++++++++ malloc/mtrace.c | 314 ++---------------------------------------- 3 files changed, 249 insertions(+), 302 deletions(-) create mode 100644 malloc/mtrace-impl.c diff --git a/malloc/malloc-debug.c b/malloc/malloc-debug.c index daf48e0633..e810d47107 100644 --- a/malloc/malloc-debug.c +++ b/malloc/malloc-debug.c @@ -49,6 +49,7 @@ enum malloc_debug_hooks { MALLOC_NONE_HOOK = 0, MALLOC_MCHECK_HOOK = 1 << 0, /* mcheck() */ + MALLOC_MTRACE_HOOK = 1 << 1, /* mtrace() */ }; static unsigned __malloc_debugging_hooks; @@ -71,6 +72,7 @@ __malloc_debug_disable (enum malloc_debug_hooks flag) } #include "mcheck.c" +#include "mtrace.c" extern void (*__free_hook) (void *, const void *); compat_symbol_reference (libc, __free_hook, __free_hook, GLIBC_2_0); @@ -103,6 +105,8 @@ __debug_malloc (size_t bytes) } if (__is_malloc_debug_enabled (MALLOC_MCHECK_HOOK) && victim != NULL) victim = malloc_mcheck_after (victim, orig_bytes); + if (__is_malloc_debug_enabled (MALLOC_MTRACE_HOOK)) + malloc_mtrace_after (victim, orig_bytes, RETURN_ADDRESS (0)); return victim; } @@ -120,6 +124,8 @@ __debug_free (void *mem) if (__is_malloc_debug_enabled (MALLOC_MCHECK_HOOK)) mem = free_mcheck (mem); + if (__is_malloc_debug_enabled (MALLOC_MTRACE_HOOK)) + free_mtrace (mem, RETURN_ADDRESS (0)); __libc_free (mem); } @@ -146,6 +152,8 @@ __debug_realloc (void *oldmem, size_t bytes) if (__is_malloc_debug_enabled (MALLOC_MCHECK_HOOK) && victim != NULL) victim = realloc_mcheck_after (victim, oldmem, orig_bytes, oldsize); + if (__is_malloc_debug_enabled (MALLOC_MTRACE_HOOK)) + realloc_mtrace_after (victim, oldmem, orig_bytes, RETURN_ADDRESS (0)); return victim; } @@ -171,6 +179,8 @@ _mid_memalign (size_t alignment, size_t bytes, const void *address) } if (__is_malloc_debug_enabled (MALLOC_MCHECK_HOOK) && victim != NULL) victim = memalign_mcheck_after (victim, alignment, orig_bytes); + if (__is_malloc_debug_enabled (MALLOC_MTRACE_HOOK)) + memalign_mtrace_after (victim, orig_bytes, address); return victim; } @@ -272,6 +282,9 @@ __debug_calloc (size_t nmemb, size_t size) victim = malloc_mcheck_after (victim, orig_bytes); memset (victim, 0, orig_bytes); } + if (__is_malloc_debug_enabled (MALLOC_MTRACE_HOOK)) + malloc_mtrace_after (victim, orig_bytes, RETURN_ADDRESS (0)); + return victim; } strong_alias (__debug_calloc, calloc) diff --git a/malloc/mtrace-impl.c b/malloc/mtrace-impl.c new file mode 100644 index 0000000000..de8e88e4f7 --- /dev/null +++ b/malloc/mtrace-impl.c @@ -0,0 +1,224 @@ +/* mtrace implementation for `malloc'. + Copyright (C) 1991-2021 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Written April 2, 1991 by John Gilmore of Cygnus Support. + Based on mcheck.c by Mike Haertel. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + + +#include +#include + +#include +#include +#include +#include +#include + +#include +#include + +#include + +#define TRACE_BUFFER_SIZE 512 + +static FILE *mallstream; +static const char mallenv[] = "MALLOC_TRACE"; +static char *malloc_trace_buffer; + +static void +tr_where (const void *caller, Dl_info *info) +{ + if (caller != NULL) + { + if (info != NULL) + { + char *buf = (char *) ""; + if (info->dli_sname != NULL) + { + size_t len = strlen (info->dli_sname); + buf = alloca (len + 6 + 2 * sizeof (void *)); + char sign; + ptrdiff_t offset = + (ptrdiff_t) info->dli_saddr - (ptrdiff_t) caller; + + if (caller >= (const void *) info->dli_saddr) + { + sign = '+'; + offset = -offset; + } + else + sign = '-'; + + sprintf (buf, "(%s%c%lx)", info->dli_sname, sign, offset); + } + + fprintf (mallstream, "@ %s%s%s[%p] ", info->dli_fname ? : "", + info->dli_fname ? ":" : "", + buf, caller); + } + else + fprintf (mallstream, "@ [%p] ", caller); + } +} + +static Dl_info * +lock_and_info (const void *caller, Dl_info *mem) +{ + if (caller == NULL) + return NULL; + + Dl_info *res = _dl_addr (caller, mem, NULL, NULL) ? mem : NULL; + + flockfile (mallstream); + + return res; +} + +static void +free_mtrace (void *ptr, const void *caller) +{ + if (ptr == NULL) + return; + + Dl_info mem; + Dl_info *info = lock_and_info (caller, &mem); + tr_where (caller, info); + /* Be sure to print it first. */ + fprintf (mallstream, "- %p\n", ptr); + funlockfile (mallstream); +} + +static void +malloc_mtrace_after (void *block, size_t size, const void *caller) +{ + Dl_info mem; + Dl_info *info = lock_and_info (caller, &mem); + + tr_where (caller, info); + /* We could be printing a NULL here; that's OK. */ + fprintf (mallstream, "+ %p %#lx\n", block, (unsigned long int) size); + + funlockfile (mallstream); +} + +static void +realloc_mtrace_after (void *block, const void *oldptr, size_t size, + const void *caller) +{ + Dl_info mem; + Dl_info *info = lock_and_info (caller, &mem); + + tr_where (caller, info); + if (block == NULL) + { + if (size != 0) + /* Failed realloc. */ + fprintf (mallstream, "! %p %#lx\n", oldptr, (unsigned long int) size); + else + fprintf (mallstream, "- %p\n", oldptr); + } + else if (oldptr == NULL) + fprintf (mallstream, "+ %p %#lx\n", block, (unsigned long int) size); + else + { + fprintf (mallstream, "< %p\n", oldptr); + tr_where (caller, info); + fprintf (mallstream, "> %p %#lx\n", block, (unsigned long int) size); + } + + funlockfile (mallstream); +} + +static void +memalign_mtrace_after (void *block, size_t size, const void *caller) +{ + Dl_info mem; + Dl_info *info = lock_and_info (caller, &mem); + + tr_where (caller, info); + /* We could be printing a NULL here; that's OK. */ + fprintf (mallstream, "+ %p %#lx\n", block, (unsigned long int) size); + + funlockfile (mallstream); +} + +/* This function gets called to make sure all memory the library + allocates get freed and so does not irritate the user when studying + the mtrace output. */ +static void +release_libc_mem (void) +{ + /* Only call the free function if we still are running in mtrace mode. */ + if (mallstream != NULL) + __libc_freeres (); +} + +/* We enable tracing if the environment variable MALLOC_TRACE is set. */ + +static void +do_mtrace (void) +{ + static int added_atexit_handler; + char *mallfile; + + /* Don't panic if we're called more than once. */ + if (mallstream != NULL) + return; + + mallfile = secure_getenv (mallenv); + if (mallfile != NULL) + { + char *mtb = malloc (TRACE_BUFFER_SIZE); + if (mtb == NULL) + return; + + mallstream = fopen (mallfile != NULL ? mallfile : "/dev/null", "wce"); + if (mallstream != NULL) + { + /* Be sure it doesn't malloc its buffer! */ + malloc_trace_buffer = mtb; + setvbuf (mallstream, malloc_trace_buffer, _IOFBF, TRACE_BUFFER_SIZE); + fprintf (mallstream, "= Start\n"); + if (!added_atexit_handler) + { + added_atexit_handler = 1; + __cxa_atexit ((void (*)(void *))release_libc_mem, NULL, + __dso_handle); + } + __malloc_debug_enable (MALLOC_MTRACE_HOOK); + } + else + free (mtb); + } +} + +static void +do_muntrace (void) +{ + __malloc_debug_disable (MALLOC_MTRACE_HOOK); + if (mallstream == NULL) + return; + + /* Do the reverse of what done in mtrace: first reset the hooks and + MALLSTREAM, and only after that write the trailer and close the + file. */ + FILE *f = mallstream; + mallstream = NULL; + + fprintf (f, "= End\n"); + fclose (f); +} diff --git a/malloc/mtrace.c b/malloc/mtrace.c index 274db3fb47..b632116dd1 100644 --- a/malloc/mtrace.c +++ b/malloc/mtrace.c @@ -1,4 +1,4 @@ -/* More debugging hooks for `malloc'. +/* mtrace API for `malloc'. Copyright (C) 1991-2021 Free Software Foundation, Inc. This file is part of the GNU C Library. Written April 2, 1991 by John Gilmore of Cygnus Support. @@ -18,40 +18,14 @@ License along with the GNU C Library; if not, see . */ -#ifndef _MALLOC_INTERNAL -# define _MALLOC_INTERNAL -# include -# include -# include -# include +#if !IS_IN (libc) +# include "mtrace-impl.c" +#else +# include +# include #endif -#include -#include -#include -#include -#include - -#include <_itoa.h> - -#include -#include - -#include -#define setvbuf(s, b, f, l) _IO_setvbuf (s, b, f, l) -#define fwrite(buf, size, count, fp) _IO_fwrite (buf, size, count, fp) - -#include - -#define TRACE_BUFFER_SIZE 512 - -static FILE *mallstream; -static const char mallenv[] = "MALLOC_TRACE"; -static char *malloc_trace_buffer; - -__libc_lock_define_initialized (static, lock); - -#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_34) +#if IS_IN (libc) && SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_34) /* Compatibility symbols that were introduced to help break at allocation sites for specific memory allocations. This is unusable with ASLR, although gdb may allow predictable allocation addresses. Even then, gdb has watchpoint @@ -71,282 +45,18 @@ compat_symbol (libc, tr_break, tr_break, GLIBC_2_0); #endif -/* Old hook values. */ -static void (*tr_old_free_hook) (void *ptr, const void *); -static void *(*tr_old_malloc_hook) (size_t size, const void *); -static void *(*tr_old_realloc_hook) (void *ptr, size_t size, - const void *); -static void *(*tr_old_memalign_hook) (size_t __alignment, size_t __size, - const void *); - -static void -tr_where (const void *caller, Dl_info *info) -{ - if (caller != NULL) - { - if (info != NULL) - { - char *buf = (char *) ""; - if (info->dli_sname != NULL) - { - size_t len = strlen (info->dli_sname); - buf = alloca (len + 6 + 2 * sizeof (void *)); - - buf[0] = '('; - __stpcpy (_fitoa (caller >= (const void *) info->dli_saddr - ? caller - (const void *) info->dli_saddr - : (const void *) info->dli_saddr - caller, - __stpcpy (__mempcpy (buf + 1, info->dli_sname, - len), - caller >= (void *) info->dli_saddr - ? "+0x" : "-0x"), - 16, 0), - ")"); - } - - fprintf (mallstream, "@ %s%s%s[%p] ", - info->dli_fname ? : "", info->dli_fname ? ":" : "", - buf, caller); - } - else - fprintf (mallstream, "@ [%p] ", caller); - } -} - -static Dl_info * -lock_and_info (const void *caller, Dl_info *mem) -{ - if (caller == NULL) - return NULL; - - Dl_info *res = _dl_addr (caller, mem, NULL, NULL) ? mem : NULL; - - __libc_lock_lock (lock); - - return res; -} - -static void tr_freehook (void *, const void *); -static void * tr_mallochook (size_t, const void *); -static void * tr_reallochook (void *, size_t, const void *); -static void * tr_memalignhook (size_t, size_t, const void *); - -/* Set all the default non-trace hooks. */ -static __always_inline void -set_default_hooks (void) -{ - __free_hook = tr_old_free_hook; - __malloc_hook = tr_old_malloc_hook; - __realloc_hook = tr_old_realloc_hook; - __memalign_hook = tr_old_memalign_hook; -} - -/* Set all of the tracing hooks used for mtrace. */ -static __always_inline void -set_trace_hooks (void) -{ - __free_hook = tr_freehook; - __malloc_hook = tr_mallochook; - __realloc_hook = tr_reallochook; - __memalign_hook = tr_memalignhook; -} - -/* Save the current set of hooks as the default hooks. */ -static __always_inline void -save_default_hooks (void) -{ - tr_old_free_hook = __free_hook; - tr_old_malloc_hook = __malloc_hook; - tr_old_realloc_hook = __realloc_hook; - tr_old_memalign_hook = __memalign_hook; -} - -static void -tr_freehook (void *ptr, const void *caller) -{ - if (ptr == NULL) - return; - - Dl_info mem; - Dl_info *info = lock_and_info (caller, &mem); - tr_where (caller, info); - /* Be sure to print it first. */ - fprintf (mallstream, "- %p\n", ptr); - set_default_hooks (); - if (tr_old_free_hook != NULL) - (*tr_old_free_hook)(ptr, caller); - else - free (ptr); - set_trace_hooks (); - __libc_lock_unlock (lock); -} - -static void * -tr_mallochook (size_t size, const void *caller) -{ - void *hdr; - - Dl_info mem; - Dl_info *info = lock_and_info (caller, &mem); - - set_default_hooks (); - if (tr_old_malloc_hook != NULL) - hdr = (void *) (*tr_old_malloc_hook)(size, caller); - else - hdr = (void *) malloc (size); - set_trace_hooks (); - - tr_where (caller, info); - /* We could be printing a NULL here; that's OK. */ - fprintf (mallstream, "+ %p %#lx\n", hdr, (unsigned long int) size); - - __libc_lock_unlock (lock); - - return hdr; -} - -static void * -tr_reallochook (void *ptr, size_t size, const void *caller) -{ - void *hdr; - - Dl_info mem; - Dl_info *info = lock_and_info (caller, &mem); - - set_default_hooks (); - if (tr_old_realloc_hook != NULL) - hdr = (void *) (*tr_old_realloc_hook)(ptr, size, caller); - else - hdr = (void *) realloc (ptr, size); - set_trace_hooks (); - - tr_where (caller, info); - if (hdr == NULL) - { - if (size != 0) - /* Failed realloc. */ - fprintf (mallstream, "! %p %#lx\n", ptr, (unsigned long int) size); - else - fprintf (mallstream, "- %p\n", ptr); - } - else if (ptr == NULL) - fprintf (mallstream, "+ %p %#lx\n", hdr, (unsigned long int) size); - else - { - fprintf (mallstream, "< %p\n", ptr); - tr_where (caller, info); - fprintf (mallstream, "> %p %#lx\n", hdr, (unsigned long int) size); - } - - __libc_lock_unlock (lock); - - return hdr; -} - -static void * -tr_memalignhook (size_t alignment, size_t size, const void *caller) -{ - void *hdr; - - Dl_info mem; - Dl_info *info = lock_and_info (caller, &mem); - - set_default_hooks (); - if (tr_old_memalign_hook != NULL) - hdr = (void *) (*tr_old_memalign_hook)(alignment, size, caller); - else - hdr = (void *) memalign (alignment, size); - set_trace_hooks (); - - tr_where (caller, info); - /* We could be printing a NULL here; that's OK. */ - fprintf (mallstream, "+ %p %#lx\n", hdr, (unsigned long int) size); - - __libc_lock_unlock (lock); - - return hdr; -} - - -#ifdef _LIBC - -/* This function gets called to make sure all memory the library - allocates get freed and so does not irritate the user when studying - the mtrace output. */ -static void __libc_freeres_fn_section -release_libc_mem (void) -{ - /* Only call the free function if we still are running in mtrace mode. */ - if (mallstream != NULL) - __libc_freeres (); -} -#endif - - -/* We enable tracing if the environment variable MALLOC_TRACE is set. */ - void mtrace (void) { -#ifdef _LIBC - static int added_atexit_handler; +#if !IS_IN (libc) + do_mtrace (); #endif - char *mallfile; - - /* Don't panic if we're called more than once. */ - if (mallstream != NULL) - return; - -#ifdef _LIBC - /* When compiling the GNU libc we use the secure getenv function - which prevents the misuse in case of SUID or SGID enabled - programs. */ - mallfile = __libc_secure_getenv (mallenv); -#else - mallfile = getenv (mallenv); -#endif - if (mallfile != NULL) - { - char *mtb = malloc (TRACE_BUFFER_SIZE); - if (mtb == NULL) - return; - - mallstream = fopen (mallfile != NULL ? mallfile : "/dev/null", "wce"); - if (mallstream != NULL) - { - /* Be sure it doesn't malloc its buffer! */ - malloc_trace_buffer = mtb; - setvbuf (mallstream, malloc_trace_buffer, _IOFBF, TRACE_BUFFER_SIZE); - fprintf (mallstream, "= Start\n"); - save_default_hooks (); - set_trace_hooks (); -#ifdef _LIBC - if (!added_atexit_handler) - { - added_atexit_handler = 1; - __cxa_atexit ((void (*)(void *))release_libc_mem, NULL, - __dso_handle); - } -#endif - } - else - free (mtb); - } } void muntrace (void) { - if (mallstream == NULL) - return; - - /* Do the reverse of what done in mtrace: first reset the hooks and - MALLSTREAM, and only after that write the trailer and close the - file. */ - FILE *f = mallstream; - mallstream = NULL; - set_default_hooks (); - - fprintf (f, "= End\n"); - fclose (f); +#if !IS_IN (libc) + do_muntrace (); +#endif }