From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5D84EC4363C for ; Sun, 4 Oct 2020 12:22:09 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8976C206A1 for ; Sun, 4 Oct 2020 12:22:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="pqAI0EQP" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8976C206A1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:54934 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kP31j-0003Fi-Ks for qemu-devel@archiver.kernel.org; Sun, 04 Oct 2020 08:22:07 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:56580) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kP30K-0002iY-1p; Sun, 04 Oct 2020 08:20:40 -0400 Received: from mail-lj1-x241.google.com ([2a00:1450:4864:20::241]:37910) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kP30H-0002QT-Qz; Sun, 04 Oct 2020 08:20:39 -0400 Received: by mail-lj1-x241.google.com with SMTP id w3so4846521ljo.5; Sun, 04 Oct 2020 05:20:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=message-id:subject:from:to:cc:date:in-reply-to:references :user-agent:mime-version:content-transfer-encoding; bh=gUGwOZQkxmPD7anmpZi8bbMrX9lFvKWVHOaabMtKDfA=; b=pqAI0EQP6Er14VEHAPNmZp8RG8CgbWsTbDCrVjv5PZQ+IA2sXERTnCfxlFSwjZywUB SvayKozUYmEI0Hm2Q67NdPAPZAAQ/a0dvB4rsxDo13VNYzwsEohmD1AwQ3sUCXh4MHMC cgt+pafsQp1kHjKL1OgGVTXMb6c+yMP6KK6CYxazyTaYmILPTDV5tv6lbHGrwFiVqKo4 yLba+e+U5l/slo7zjc3bEqpgvVJc5lt+POhsiE3Nyxozl/Q8bwE8oY20V0SPvJH0VRaW Q2AEciQOG0wSNNcpCxy4ucWkFzuvwyG/fv+uPdAiWd1egaQ0NCDGme9jnuoxDjgRFlxT Xr3A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:subject:from:to:cc:date:in-reply-to :references:user-agent:mime-version:content-transfer-encoding; bh=gUGwOZQkxmPD7anmpZi8bbMrX9lFvKWVHOaabMtKDfA=; b=dLvjLy8Z4az/PF4mCZAW3Y8kKkN6s3VruT6sfPqHxJO4uGgm52um3xEQuY6CiMiUQ2 n/wLlgNYjKMHpXS47TOB6ekxpqKxkW1G6TTrJ8WRKfBEj0Dezd0K5pjP1M6KavngqBYm F/TdE9UYDqlPnEXUpC9M/L/CTsnhhQltCsq6aikeeGOudZh80HjsuKfi5d2TUh6eB/Qx z0tYzt4802v0DT6SUbuRXH/mGEi9QIwAO6iiS6h61cNc5muRmi5rZAd1ffh1JOre1760 ALam5NzUoIGlWpTJ6QPUnCcUM48/9rKTPRdI7dlj09jfwIewJSDk3RpoPeMe2H5Dteq4 YdmA== X-Gm-Message-State: AOAM530t35hOAeL/Vtdlre0Fk7z1PCbM9krSUCOf5Yli4EKtmwQl4guw D4U896PRUfw08xPMKuj77ps= X-Google-Smtp-Source: ABdhPJxgbSwb1WlcH+FASiaFUo6MZy4RbDr7m/3UZWoKiC/pqzP96KAK7zPFVq76pSyAkD1KMrrRVg== X-Received: by 2002:a2e:7809:: with SMTP id t9mr2603458ljc.115.1601814034833; Sun, 04 Oct 2020 05:20:34 -0700 (PDT) Received: from [192.168.167.128] (37-145-186-126.broadband.corbina.ru. [37.145.186.126]) by smtp.gmail.com with ESMTPSA id m13sm2380333lfb.172.2020.10.04.05.20.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 04 Oct 2020 05:20:34 -0700 (PDT) Message-ID: Subject: Re: [PATCH v2] elfload: use g_new/g_malloc and g_autofree From: Elena Afanasova To: Eric Blake , Markus Armbruster , Thomas Huth , kamil@netbsd.org, brad@comstyle.com, emaste@freebsd.org, lwhsu@freebsd.org Date: Sun, 04 Oct 2020 05:20:18 -0700 In-Reply-To: <17636b91-e111-1b60-4eb2-d526df4a6bb6@redhat.com> References: <20201001123807.42978-1-eafanasova@gmail.com> <87r1qhtdxt.fsf@dusky.pond.sub.org> <87eemhm2b9.fsf@dusky.pond.sub.org> <17636b91-e111-1b60-4eb2-d526df4a6bb6@redhat.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.36.4-0ubuntu1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=2a00:1450:4864:20::241; envelope-from=eafanasova@gmail.com; helo=mail-lj1-x241.google.com X-detected-operating-system: by eggs.gnu.org: No matching host in p0f cache. That's all we know. X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-trivial@nongnu.org, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Subject: [PATCH v2] elfload: use g_new/g_malloc and g_autofree Signed-off-by: Elena Afanasova --- bsd-user/elfload.c | 79 ++++++++-------------------------------------- 1 file changed, 14 insertions(+), 65 deletions(-) diff --git a/bsd-user/elfload.c b/bsd-user/elfload.c index 32378af7b2..bc4be4c874 100644 --- a/bsd-user/elfload.c +++ b/bsd-user/elfload.c @@ -838,7 +838,7 @@ static abi_ulong load_elf_interp(struct elfhdr * interp_elf_ex, int interpreter_fd, abi_ulong *interp_load_addr) { - struct elf_phdr *elf_phdata = NULL; + g_autofree struct elf_phdr *elf_phdata = NULL; struct elf_phdr *eppnt; abi_ulong load_addr = 0; int load_addr_set = 0; @@ -867,18 +867,13 @@ static abi_ulong load_elf_interp(struct elfhdr * interp_elf_ex, if (sizeof(struct elf_phdr) * interp_elf_ex->e_phnum > TARGET_PAGE_SIZE) return ~(abi_ulong)0UL; - elf_phdata = (struct elf_phdr *) - malloc(sizeof(struct elf_phdr) * interp_elf_ex->e_phnum); - - if (!elf_phdata) - return ~((abi_ulong)0UL); + elf_phdata = g_new(struct elf_phdr, interp_elf_ex->e_phnum); /* * If the size of this structure has changed, then punt, since * we will be doing the wrong thing. */ if (interp_elf_ex->e_phentsize != sizeof(struct elf_phdr)) { - free(elf_phdata); return ~((abi_ulong)0UL); } @@ -891,7 +886,6 @@ static abi_ulong load_elf_interp(struct elfhdr * interp_elf_ex, if (retval < 0) { perror("load_elf_interp"); exit(-1); - free (elf_phdata); return retval; } #ifdef BSWAP_NEEDED @@ -940,7 +934,6 @@ static abi_ulong load_elf_interp(struct elfhdr * interp_elf_ex, if (error == -1) { /* Real error */ close(interpreter_fd); - free(elf_phdata); return ~((abi_ulong)0UL); } @@ -983,7 +976,6 @@ static abi_ulong load_elf_interp(struct elfhdr * interp_elf_ex, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_FIXED|MAP_PRIVATE|MAP_ANON, -1, 0); } - free(elf_phdata); *interp_load_addr = load_addr; return ((abi_ulong) interp_elf_ex->e_entry) + load_addr; @@ -1036,9 +1028,10 @@ static void load_symbols(struct elfhdr *hdr, int fd) { unsigned int i, nsyms; struct elf_shdr sechdr, symtab, strtab; - char *strings; - struct syminfo *s; - struct elf_sym *syms, *new_syms; + g_autofree char *strings = NULL; + g_autofree struct syminfo *s = NULL; + g_autofree struct elf_sym *syms = NULL; + struct elf_sym *new_syms; lseek(fd, hdr->e_shoff, SEEK_SET); for (i = 0; i < hdr->e_shnum; i++) { @@ -1064,24 +1057,12 @@ static void load_symbols(struct elfhdr *hdr, int fd) found: /* Now know where the strtab and symtab are. Snarf them. */ - s = malloc(sizeof(*s)); - syms = malloc(symtab.sh_size); - if (!syms) { - free(s); - return; - } - s->disas_strtab = strings = malloc(strtab.sh_size); - if (!s->disas_strtab) { - free(s); - free(syms); - return; - } + s = g_new(struct syminfo, 1); + syms = g_malloc(symtab.sh_size); + s->disas_strtab = strings = g_new(char, strtab.sh_size); lseek(fd, symtab.sh_offset, SEEK_SET); if (read(fd, syms, symtab.sh_size) != symtab.sh_size) { - free(s); - free(syms); - free(strings); return; } @@ -1113,22 +1094,13 @@ static void load_symbols(struct elfhdr *hdr, int fd) that we threw away. Whether or not this has any effect on the memory allocation depends on the malloc implementation and how many symbols we managed to discard. */ - new_syms = realloc(syms, nsyms * sizeof(*syms)); - if (new_syms == NULL) { - free(s); - free(syms); - free(strings); - return; - } + new_syms = g_realloc(syms, nsyms * sizeof(*syms)); syms = new_syms; qsort(syms, nsyms, sizeof(*syms), symcmp); lseek(fd, strtab.sh_offset, SEEK_SET); if (read(fd, strings, strtab.sh_size) != strtab.sh_size) { - free(s); - free(syms); - free(strings); return; } s->disas_num_syms = nsyms; @@ -1156,10 +1128,10 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs, unsigned char ibcs2_interpreter; int i; struct elf_phdr * elf_ppnt; - struct elf_phdr *elf_phdata; + g_autofree struct elf_phdr *elf_phdata = NULL; abi_ulong elf_bss, k, elf_brk; int retval; - char * elf_interpreter; + g_autofree char *elf_interpreter = NULL; abi_ulong elf_entry, interp_load_addr = 0; abi_ulong start_code, end_code, start_data, end_data; abi_ulong reloc_func_desc = 0; @@ -1190,10 +1162,7 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs, } /* Now read in all of the header information */ - elf_phdata = (struct elf_phdr *)malloc(elf_ex.e_phentsize*elf_ex.e_phnum); - if (elf_phdata == NULL) { - return -ENOMEM; - } + elf_phdata = g_new(struct elf_phdr, elf_ex.e_phnum); retval = lseek(bprm->fd, elf_ex.e_phoff, SEEK_SET); if(retval > 0) { @@ -1204,7 +1173,6 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs, if (retval < 0) { perror("load_elf_binary"); exit(-1); - free (elf_phdata); return -errno; } @@ -1220,7 +1188,6 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs, elf_brk = 0; - elf_interpreter = NULL; start_code = ~((abi_ulong)0UL); end_code = 0; start_data = 0; @@ -1231,8 +1198,6 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs, if (elf_ppnt->p_type == PT_INTERP) { if ( elf_interpreter != NULL ) { - free (elf_phdata); - free(elf_interpreter); close(bprm->fd); return -EINVAL; } @@ -1242,13 +1207,7 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs, * is an a.out format binary */ - elf_interpreter = (char *)malloc(elf_ppnt->p_filesz); - - if (elf_interpreter == NULL) { - free (elf_phdata); - close(bprm->fd); - return -ENOMEM; - } + elf_interpreter = g_new(char, elf_ppnt->p_filesz); retval = lseek(bprm->fd, elf_ppnt->p_offset, SEEK_SET); if(retval >= 0) { @@ -1298,8 +1257,6 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs, if (retval < 0) { perror("load_elf_binary3"); exit(-1); - free (elf_phdata); - free(elf_interpreter); close(bprm->fd); return retval; } @@ -1323,8 +1280,6 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs, } if (!interpreter_type) { - free(elf_interpreter); - free(elf_phdata); close(bprm->fd); return -ELIBBAD; } @@ -1346,8 +1301,6 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs, } } if (!bprm->p) { - free(elf_interpreter); - free (elf_phdata); close(bprm->fd); return -E2BIG; } @@ -1486,18 +1439,14 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs, reloc_func_desc = interp_load_addr; close(interpreter_fd); - free(elf_interpreter); if (elf_entry == ~((abi_ulong)0UL)) { printf("Unable to load interpreter\n"); - free(elf_phdata); exit(-1); return 0; } } - free(elf_phdata); - if (qemu_log_enabled()) load_symbols(&elf_ex, bprm->fd); -- 2.25.1 On Fri, 2020-10-02 at 10:08 -0500, Eric Blake wrote: > On 10/2/20 3:58 AM, Markus Armbruster wrote: > > > > > > @@ -890,9 +886,8 @@ static abi_ulong load_elf_interp(struct > > > > > elfhdr * interp_elf_ex, > > > > > } > > > > > if (retval < 0) { > > > > > perror("load_elf_interp"); > > > > > + g_free(elf_phdata); > > > > > exit(-1); > > > > > - free (elf_phdata); > > > > > - return retval; > > > > > > > > Deleting return looks wrong. > > > > > > Why? There is an exit(-1) right in front of it, so this is dead > > > code... > > > well, maybe that should be done in a separate patch, or at least > > > mentioned in the patch description, though. > > > > You're right; I missed the exit(-1). > > > > Following the unpleasant odour spread by exit(-1)... Aha, the > > function's behavior on error is inconsistent: sometimes it returns > > zero, > > sometimes it exits. > > Eradicating exit(-1) (which is indistinguishable from exit(255), and > generally not what you want, unless your program is designed to > specifically invoke the immediate-exit semantics of xargs) is also a > worthwhile cleanup project. But I agree with the advice for separate > patches for separate bugs. > > > Since the problem is bigger than just one dead return, I recommend > > leaving it to a separate patch, and keeping this one focused on > > g_new(). > > > >