From patchwork Sun Nov 7 12:48:45 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Henderson X-Patchwork-Id: 1551963 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: bilbo.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=linaro.org header.i=@linaro.org header.a=rsa-sha256 header.s=google header.b=R6GTb44w; dkim-atps=neutral Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) 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 bilbo.ozlabs.org (Postfix) with ESMTPS id 4HnDbs3zCZz9sWJ for ; Sun, 7 Nov 2021 23:50:01 +1100 (AEDT) Received: from localhost ([::1]:41642 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mjhcV-00036o-4v for incoming@patchwork.ozlabs.org; Sun, 07 Nov 2021 07:49:59 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:40944) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mjhbQ-000347-Jq for qemu-devel@nongnu.org; Sun, 07 Nov 2021 07:48:53 -0500 Received: from mail-qv1-xf30.google.com ([2607:f8b0:4864:20::f30]:43957) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1mjhbN-00026X-Gq for qemu-devel@nongnu.org; Sun, 07 Nov 2021 07:48:52 -0500 Received: by mail-qv1-xf30.google.com with SMTP id j9so10249976qvm.10 for ; Sun, 07 Nov 2021 04:48:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=lAg3JSFvjX0uMfpuVPcBgi6f8K/h/oAtcH5TT2VrIrU=; b=R6GTb44wDyRiODByJbIFpoSS8/ko/9PV/EUI6VGRSnkvWVk2TlKgzyZcO9FOkKHBEk Hi+t0FGeCrBhGvc43vkjU8n1/G8AB+CaL1XABHNTTqZx48HtUrk3tRy2v0y/UF7qzeG+ s11gP8QelrY88JwZbaOXA37KXkHZeT6hUV1TprVegmSpB7g8gJUvjg60nZOOe8zY1oFz aknjPvUAFZsfidJgQJ2BOEvdvNwPMKuCfQu8LYV3ZjiKaDCAZQlQ7KlLcO8wmN4P646K 9HWQeXMwsE7PLXldvgJKNSTZIG7nd9s7d0YHBk0gusctLWBluM2qahEfzW7SBUypXmuz MZuA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=lAg3JSFvjX0uMfpuVPcBgi6f8K/h/oAtcH5TT2VrIrU=; b=yG0RxnCCUuUmDO+nAxeVYZMIHSTjV94zzUGpT/GgpzAT8Q/4EQT4d8ByUy0K1I1e2x Y8/tDGCQpqeddiw9J9wbNCe5gbw7F1tcmqifBwX094SO/waoiZTFeKI5lNSLmPSLVDja /O7RncVovySjf0JIYp3XE+J3ZkAz9Ls8tXm350Adcpj3w6W+szNtLvwZwhqHVQ/TkWDG aaK6F2I2C91GfTKak8I7W/3n4p+jm/Ljt+EjUhWYLhsidAdMVtw59TUGbAvnSFIAfPBR JPhzCSbGuj8NS6Y0q6XN8zBj0ZUTLZ7Fe0a/pMSmNRFx/3cSyhPFNbaLi4zp/Jijsqin A6HA== X-Gm-Message-State: AOAM5312Rd+axNDNCkNztR+MOCGsKZXMRDfjF7OicnT4r1vxUytvVhwV PCC10kx2//65HqSvu2nU1rn1MF9vFdtnAA== X-Google-Smtp-Source: ABdhPJwbwq6oEW3mmGZitYMywZv8yhD+dgPLB34Bz+Wfw+sb6vyz/ry5VkPuacUQd4N14BbSjWlknw== X-Received: by 2002:a05:6214:2307:: with SMTP id gc7mr11435100qvb.34.1636289328658; Sun, 07 Nov 2021 04:48:48 -0800 (PST) Received: from localhost.localdomain ([38.66.81.217]) by smtp.gmail.com with ESMTPSA id w19sm6917qkw.49.2021.11.07.04.48.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 07 Nov 2021 04:48:48 -0800 (PST) From: Richard Henderson To: qemu-devel@nongnu.org Subject: [PATCH 4/4] linux-user: Rewrite do_getdents, do_getdents64 Date: Sun, 7 Nov 2021 07:48:45 -0500 Message-Id: <20211107124845.1174791-5-richard.henderson@linaro.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211107124845.1174791-1-richard.henderson@linaro.org> References: <20211107124845.1174791-1-richard.henderson@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::f30; envelope-from=richard.henderson@linaro.org; helo=mail-qv1-xf30.google.com 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, 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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: f4bug@amsat.org, laurent@vivier.eu Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Always allocate host storage; this ensures that the struct is sufficiently aligned for the host. Merge the three host implementations of getdents via a few ifdefs. Utilize the same method for do_getdents64. Resolves: https://gitlab.com/qemu-project/qemu/-/issues/704 Signed-off-by: Richard Henderson --- linux-user/syscall.c | 251 ++++++++++++++++++------------------------- 1 file changed, 105 insertions(+), 146 deletions(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 499415ad81..01efd5773b 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -8140,172 +8140,131 @@ static int host_to_target_cpu_mask(const unsigned long *host_mask, } #ifdef TARGET_NR_getdents -static int do_getdents(abi_long arg1, abi_long arg2, abi_long arg3) +static int do_getdents(abi_long arg1, abi_long arg2, abi_long count) { - int ret; + g_autofree void *hdirp = NULL; + void *tdirp; + int hlen, hoff, toff; + int hreclen, treclen; -#ifdef EMULATE_GETDENTS_WITH_GETDENTS -# if TARGET_ABI_BITS == 32 && HOST_LONG_BITS == 64 - struct target_dirent *target_dirp; - struct linux_dirent *dirp; - abi_long count = arg3; - - dirp = g_try_malloc(count); - if (!dirp) { + hdirp = g_try_malloc(count); + if (!hdirp) { return -TARGET_ENOMEM; } - ret = get_errno(sys_getdents(arg1, dirp, count)); - if (!is_error(ret)) { - struct linux_dirent *de; - struct target_dirent *tde; - int len = ret; - int reclen, treclen; - int count1, tnamelen; - - count1 = 0; - de = dirp; - target_dirp = lock_user(VERIFY_WRITE, arg2, count, 0); - if (!target_dirp) { - return -TARGET_EFAULT; - } - tde = target_dirp; - while (len > 0) { - reclen = de->d_reclen; - tnamelen = reclen - offsetof(struct linux_dirent, d_name); - assert(tnamelen >= 0); - treclen = tnamelen + offsetof(struct target_dirent, d_name); - assert(count1 + treclen <= count); - tde->d_reclen = tswap16(treclen); - tde->d_ino = tswapal(de->d_ino); - tde->d_off = tswapal(de->d_off); - memcpy(tde->d_name, de->d_name, tnamelen); - de = (struct linux_dirent *)((char *)de + reclen); - len -= reclen; - tde = (struct target_dirent *)((char *)tde + treclen); - count1 += treclen; - } - ret = count1; - unlock_user(target_dirp, arg2, ret); - } - g_free(dirp); -# else - struct linux_dirent *dirp; - abi_long count = arg3; - - dirp = lock_user(VERIFY_WRITE, arg2, count, 0); - if (!dirp) { - return -TARGET_EFAULT; - } - ret = get_errno(sys_getdents(arg1, dirp, count)); - if (!is_error(ret)) { - struct linux_dirent *de; - int len = ret; - int reclen; - de = dirp; - while (len > 0) { - reclen = de->d_reclen; - if (reclen > len) { - break; - } - de->d_reclen = tswap16(reclen); - tswapls(&de->d_ino); - tswapls(&de->d_off); - de = (struct linux_dirent *)((char *)de + reclen); - len -= reclen; - } - } - unlock_user(dirp, arg2, ret); -# endif +#ifdef EMULATE_GETDENTS_WITH_GETDENTS + hlen = sys_getdents(arg1, hdirp, count); #else - /* Implement getdents in terms of getdents64 */ - struct linux_dirent64 *dirp; - abi_long count = arg3; + hlen = sys_getdents64(arg1, hdirp, count); +#endif - dirp = lock_user(VERIFY_WRITE, arg2, count, 0); - if (!dirp) { + hlen = get_errno(hlen); + if (is_error(hlen)) { + return hlen; + } + + tdirp = lock_user(VERIFY_WRITE, arg2, count, 0); + if (!tdirp) { return -TARGET_EFAULT; } - ret = get_errno(sys_getdents64(arg1, dirp, count)); - if (!is_error(ret)) { - /* - * Convert the dirent64 structs to target dirent. We do this - * in-place, since we can guarantee that a target_dirent is no - * larger than a dirent64; however this means we have to be - * careful to read everything before writing in the new format. - */ - struct linux_dirent64 *de; - struct target_dirent *tde; - int len = ret; - int tlen = 0; - de = dirp; - tde = (struct target_dirent *)dirp; - while (len > 0) { - int namelen, treclen; - int reclen = de->d_reclen; - uint64_t ino = de->d_ino; - int64_t off = de->d_off; - uint8_t type = de->d_type; - - namelen = strlen(de->d_name); - treclen = offsetof(struct target_dirent, d_name) + namelen + 2; - treclen = QEMU_ALIGN_UP(treclen, sizeof(abi_long)); - - memmove(tde->d_name, de->d_name, namelen + 1); - tde->d_ino = tswapal(ino); - tde->d_off = tswapal(off); - tde->d_reclen = tswap16(treclen); - /* - * The target_dirent type is in what was formerly a padding - * byte at the end of the structure: - */ - *(((char *)tde) + treclen - 1) = type; - - de = (struct linux_dirent64 *)((char *)de + reclen); - tde = (struct target_dirent *)((char *)tde + treclen); - len -= reclen; - tlen += treclen; - } - ret = tlen; - } - unlock_user(dirp, arg2, ret); + for (hoff = toff = 0; hoff < hlen; hoff += hreclen, toff += treclen) { +#ifdef EMULATE_GETDENTS_WITH_GETDENTS + struct linux_dirent *hde = hdirp + hoff; +#else + struct linux_dirent64 *hde = hdirp + hoff; #endif - return ret; + struct target_dirent *tde = tdirp + toff; + int namelen; + uint8_t type; + + /* + * If somehow the host dirent is smaller than the target dirent, + * then the host could return more dirent in the buffer than we + * can pass on to the host. This could be fixed by returning + * fewer dirent to the guest and lseek on the dirfd to reset the + * file pointer to the final hde->d_off. + */ + QEMU_BUILD_BUG_ON(sizeof(*hde) < sizeof(*tde)); + + namelen = strlen(hde->d_name); + hreclen = hde->d_reclen; + treclen = offsetof(struct target_dirent, d_name) + namelen + 2; + treclen = QEMU_ALIGN_UP(treclen, __alignof(struct target_dirent)); + + tde->d_ino = tswapal(hde->d_ino); + tde->d_off = tswapal(hde->d_off); + tde->d_reclen = tswap16(treclen); + memcpy(tde->d_name, hde->d_name, namelen + 1); + + /* + * The getdents type is in what was formerly a padding byte at the + * end of the structure. + */ +#ifdef EMULATE_GETDENTS_WITH_GETDENTS + type = *((uint8_t *)hde + hreclen - 1); +#else + type = hde->d_type; +#endif + *((uint8_t *)tde + treclen - 1) = type; + } + + unlock_user(tdirp, arg2, toff); + return toff; } #endif /* TARGET_NR_getdents */ #if defined(TARGET_NR_getdents64) && defined(__NR_getdents64) -static int do_getdents64(abi_long arg1, abi_long arg2, abi_long arg3) +static int do_getdents64(abi_long arg1, abi_long arg2, abi_long count) { - struct linux_dirent64 *dirp; - abi_long count = arg3; - int ret; + g_autofree void *hdirp = NULL; + void *tdirp; + int hlen, hoff, toff; + int hreclen, treclen; - dirp = lock_user(VERIFY_WRITE, arg2, count, 0); - if (!dirp) { + hdirp = g_try_malloc(count); + if (!hdirp) { + return -TARGET_ENOMEM; + } + + hlen = get_errno(sys_getdents64(arg1, hdirp, count)); + if (is_error(hlen)) { + return hlen; + } + + tdirp = lock_user(VERIFY_WRITE, arg2, count, 0); + if (!tdirp) { return -TARGET_EFAULT; } - ret = get_errno(sys_getdents64(arg1, dirp, count)); - if (!is_error(ret)) { - struct linux_dirent64 *de; - int len = ret; - int reclen; - de = dirp; - while (len > 0) { - reclen = de->d_reclen; - if (reclen > len) { - break; - } - de->d_reclen = tswap16(reclen); - tswap64s((uint64_t *)&de->d_ino); - tswap64s((uint64_t *)&de->d_off); - de = (struct linux_dirent64 *)((char *)de + reclen); - len -= reclen; - } + + for (hoff = toff = 0; hoff < hlen; hoff += hreclen, toff += treclen) { + struct linux_dirent64 *hde = hdirp + hoff; + struct target_dirent64 *tde = tdirp + toff; + int namelen; + + /* + * If somehow the host dirent is smaller than the target dirent, + * then the host could return more dirent in the buffer than we + * can pass on to the host. This could be fixed by returning + * fewer dirent to the guest and lseek on the dirfd to reset the + * file pointer to the final hde->d_off. + */ + QEMU_BUILD_BUG_ON(sizeof(*hde) < sizeof(*tde)); + + namelen = strlen(hde->d_name) + 1; + hreclen = hde->d_reclen; + treclen = offsetof(struct target_dirent64, d_name) + namelen; + treclen = QEMU_ALIGN_UP(treclen, __alignof(struct target_dirent64)); + + tde->d_ino = tswap64(hde->d_ino); + tde->d_off = tswap64(hde->d_off); + tde->d_reclen = tswap16(treclen); + tde->d_type = hde->d_type; + memcpy(tde->d_name, hde->d_name, namelen); } - unlock_user(dirp, arg2, ret); - return ret; + + unlock_user(tdirp, arg2, toff); + return toff; } #endif /* TARGET_NR_getdents64 */