From patchwork Thu Jul 23 00:19:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shu-Chun Weng X-Patchwork-Id: 277560 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=-20.6 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=unavailable 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 C6B2EC433DF for ; Thu, 23 Jul 2020 00:21:24 +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 7C7B520825 for ; Thu, 23 Jul 2020 00:21:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="eZ0r1Kgs" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7C7B520825 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:36528 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jyOzD-00056H-Oh for qemu-devel@archiver.kernel.org; Wed, 22 Jul 2020 20:21:23 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58374) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from <3odcYXwMKCrIkUoYggYdW.UgeiWem-VWnWdfgfYfm.gjY@flex--scw.bounces.google.com>) id 1jyOxk-0003Ni-2U for qemu-devel@nongnu.org; Wed, 22 Jul 2020 20:19:52 -0400 Received: from mail-yb1-xb49.google.com ([2607:f8b0:4864:20::b49]:37859) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from <3odcYXwMKCrIkUoYggYdW.UgeiWem-VWnWdfgfYfm.gjY@flex--scw.bounces.google.com>) id 1jyOxh-00024T-Sn for qemu-devel@nongnu.org; Wed, 22 Jul 2020 20:19:51 -0400 Received: by mail-yb1-xb49.google.com with SMTP id e135so4535433ybf.4 for ; Wed, 22 Jul 2020 17:19:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=XQ2622JAxk5T9LN28W6/btS5omHEQqR3RjN3a6hCK6k=; b=eZ0r1Kgssz8S/OB08jH22yr4U+bYoL52Lkz8piANEd/GGNGQm1zm44+ku7Vl8rywdc V0QivId/EpvNh23uojuO6jzkUfWwcRQc0GetFquk7H4mZS9ErskIJtz9pHIoKFddLd1a 4D78GMiGexzma4w4nuMC5nfpcuHVk5H70AKp+F5R7f1Tvv2LKNPFNewla7wz2XG4rwV1 edizAmFrUr3vm5KFrSQTNmYSogR1QgINL7Zjj5NY5Dy+aIjua/7IOK9/YP/a/IDGyzxQ HmdckJtUCaBJOxhb71JWsg2924op8MhqqcjHI2G8M7JArsHF+Qx7vdvnOp8ShMcyIEjZ KiXw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=XQ2622JAxk5T9LN28W6/btS5omHEQqR3RjN3a6hCK6k=; b=gEBh80+U5itWCg6EcYcI+CKrpZKMJybfSq2iRbd0/FMEOQoZX0i6646BRivk2jX3rm FZgx+04Vpzvo8NvuBjrnU6uHnbCOQzvhsav+PHYMtELWtU/ZZOJsvtwP96RedemHEP6d 1exuh6VsJ6zqQqX1o1GzviP8oJA5q1Vo5A+aQOlqa06c3HnO0x0I8OvkaVRIrjdTUhrf Nk7zulGnEm4D4zmSTlIKP7aGNb3UJ+l7I8LW2nR4Zsrxbm8bvIeWL6St+wVvNwJESdLr CSiiP4aKh1PSaHgKc6BWA8gFfrpg27ZaIjEn2Ud1u4UJdfX2d3Z6pbxEgGRupfHBZhQz 6uLA== X-Gm-Message-State: AOAM530YAArdw1pPdirAly4JTOoogbzNqkHvnZqBvgM2jhpt19dyEpvD GBf5tYy5O6GwGS6ie+d14wRCMrqG7nopsOZ+uPhww7tuNMXlwt+5Cj7cwz8S2C37I/MoGnNRxB4 TtsI7SAEqlM2AsvwWsyQTdU/KI7HrGhKKKXLmCdGgkUo1wPjHxB/7 X-Google-Smtp-Source: ABdhPJxYCQkfdIesHI5Y8B7ouiFl2bjZchIKnIj1UzIzHIWUcQhC3QgI5PJ9msVJz3S7YGarM1blrO4= X-Received: by 2002:a25:7e41:: with SMTP id z62mr2893188ybc.463.1595463585034; Wed, 22 Jul 2020 17:19:45 -0700 (PDT) Date: Wed, 22 Jul 2020 17:19:14 -0700 In-Reply-To: Message-Id: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.28.0.rc0.105.gf9edc3c819-goog Subject: [PATCH 5/6] thunk: supports flexible arrays From: Shu-Chun Weng To: qemu-devel@nongnu.org Cc: Shu-Chun Weng , laurent@vivier.eu, riku.voipio@iki.fi Received-SPF: pass client-ip=2607:f8b0:4864:20::b49; envelope-from=3odcYXwMKCrIkUoYggYdW.UgeiWem-VWnWdfgfYfm.gjY@flex--scw.bounces.google.com; helo=mail-yb1-xb49.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: -105 X-Spam_score: -10.6 X-Spam_bar: ---------- X-Spam_report: (-10.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_MED=-1, 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, USER_IN_DEF_DKIM_WL=-7.5 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Flexible arrays may appear in the last field of a struct and are heavily used in the ioctl(SIOCETHTOOL) system call on Linux. E.g. struct ethtool_regs { __u32 cmd; __u32 version; /* driver-specific, indicates different chips/revs */ __u32 len; /* bytes */ __u8 data[0]; }; where number of elements in `data` is specified in `len`. It is translated into: STRUCT(ethtool_regs, TYPE_INT, /* cmd */ TYPE_INT, /* version */ TYPE_INT, /* len */ MK_FLEXIBLE_ARRAY(TYPE_CHAR, 2)) /* data[0]: len */ where the "2" passed to `MK_FLEXIBLE_ARRAY` means the number of element is specified by field number 2 (0-index). Signed-off-by: Shu-Chun Weng --- include/exec/user/thunk.h | 20 +++++ thunk.c | 151 +++++++++++++++++++++++++++++++++++++- 2 files changed, 169 insertions(+), 2 deletions(-) diff --git a/include/exec/user/thunk.h b/include/exec/user/thunk.h index 7992475c9f..080d84e806 100644 --- a/include/exec/user/thunk.h +++ b/include/exec/user/thunk.h @@ -39,12 +39,19 @@ typedef enum argtype { TYPE_ARRAY, TYPE_STRUCT, TYPE_OLDDEVT, + TYPE_FLEXIBLE_ARRAY, } argtype; #define MK_PTR(type) TYPE_PTR, type #define MK_ARRAY(type, size) TYPE_ARRAY, size, type #define MK_STRUCT(id) TYPE_STRUCT, id +/* Should only appear as the last element of a TYPE_STRUCT. `len_field_idx` is + * the index into the fields in the enclosing struct that specify the length of + * the flexibly array. The length field MUST be a TYPE_INT field. */ +#define MK_FLEXIBLE_ARRAY(type, len_field_idx) \ + TYPE_FLEXIBLE_ARRAY, len_field_idx, type + #define THUNK_TARGET 0 #define THUNK_HOST 1 @@ -55,6 +62,8 @@ typedef struct { int *field_offsets[2]; /* special handling */ void (*convert[2])(void *dst, const void *src); + int (*thunk_size[2])(const void *src); + int size[2]; int align[2]; const char *name; @@ -75,6 +84,11 @@ const argtype *thunk_convert(void *dst, const void *src, const argtype *type_ptr, int to_host); const argtype *thunk_print(void *arg, const argtype *type_ptr); +bool thunk_type_has_flexible_array(const argtype *type_ptr); +/* thunk_type_size but can handle TYPE_FLEXIBLE_ARRAY */ +int thunk_type_size_with_src(const void *src, const argtype *type_ptr, + int is_host); + extern StructEntry *struct_entries; int thunk_type_size_array(const argtype *type_ptr, int is_host); @@ -137,6 +151,10 @@ static inline int thunk_type_size(const argtype *type_ptr, int is_host) case TYPE_STRUCT: se = struct_entries + type_ptr[1]; return se->size[is_host]; + case TYPE_FLEXIBLE_ARRAY: + /* Flexible arrays do not count toward sizeof(). Users of structures + * containing them need to calculate it themselves. */ + return 0; default: g_assert_not_reached(); } @@ -187,6 +205,8 @@ static inline int thunk_type_align(const argtype *type_ptr, int is_host) case TYPE_STRUCT: se = struct_entries + type_ptr[1]; return se->align[is_host]; + case TYPE_FLEXIBLE_ARRAY: + return thunk_type_align_array(type_ptr + 2, is_host); default: g_assert_not_reached(); } diff --git a/thunk.c b/thunk.c index c5d9719747..7b89332712 100644 --- a/thunk.c +++ b/thunk.c @@ -50,6 +50,8 @@ static inline const argtype *thunk_type_next(const argtype *type_ptr) return thunk_type_next_ptr(type_ptr + 1); case TYPE_STRUCT: return type_ptr + 1; + case TYPE_FLEXIBLE_ARRAY: + return thunk_type_next_ptr(type_ptr + 1); default: return NULL; } @@ -122,6 +124,34 @@ void thunk_register_struct_direct(int id, const char *name, se->name = name; } +static const argtype * +thunk_convert_flexible_array(void *dst, const void *src, + const uint8_t *dst_struct, + const uint8_t *src_struct, const argtype *type_ptr, + const StructEntry *se, int to_host) { + int len_field_idx, dst_size, src_size, i; + uint32_t array_length; + uint8_t *d; + const uint8_t *s; + + assert(*type_ptr == TYPE_FLEXIBLE_ARRAY); + type_ptr++; + len_field_idx = *type_ptr++; + array_length = + *(const uint32_t *)(to_host ? + dst_struct + se->field_offsets[1][len_field_idx] : + src_struct + se->field_offsets[0][len_field_idx]); + dst_size = thunk_type_size(type_ptr, to_host); + src_size = thunk_type_size(type_ptr, to_host); + d = dst; + s = src; + for (i = 0; i < array_length; i++) { + thunk_convert(d, s, type_ptr, to_host); + d += dst_size; + s += src_size; + } + return thunk_type_next(type_ptr); +} /* now we can define the main conversion functions */ const argtype *thunk_convert(void *dst, const void *src, @@ -246,7 +276,7 @@ const argtype *thunk_convert(void *dst, const void *src, assert(*type_ptr < max_struct_entries); se = struct_entries + *type_ptr++; - if (se->convert[0] != NULL) { + if (se->convert[to_host] != NULL) { /* specific conversion is needed */ (*se->convert[to_host])(dst, src); } else { @@ -256,7 +286,18 @@ const argtype *thunk_convert(void *dst, const void *src, src_offsets = se->field_offsets[1 - to_host]; d = dst; s = src; - for(i = 0;i < se->nb_fields; i++) { + for(i = 0; i < se->nb_fields; i++) { + if (*field_types == TYPE_FLEXIBLE_ARRAY) { + field_types = thunk_convert_flexible_array( + d + dst_offsets[i], + s + src_offsets[i], + d, + s, + field_types, + se, + to_host); + continue; + } field_types = thunk_convert(d + dst_offsets[i], s + src_offsets[i], field_types, to_host); @@ -264,6 +305,11 @@ const argtype *thunk_convert(void *dst, const void *src, } } break; + case TYPE_FLEXIBLE_ARRAY: + fprintf(stderr, + "Invalid flexible array (type 0x%x) outside of a structure\n", + type); + break; default: fprintf(stderr, "Invalid type 0x%x\n", type); break; @@ -271,6 +317,45 @@ const argtype *thunk_convert(void *dst, const void *src, return type_ptr; } +static const argtype * +thunk_print_flexible_array(void *arg, const uint8_t *arg_struct, + const argtype *type_ptr, const StructEntry *se) { + int array_length, len_field_idx, arg_size, i; + uint8_t *a; + int is_string = 0; + + assert(*type_ptr == TYPE_FLEXIBLE_ARRAY); + type_ptr++; + len_field_idx = *type_ptr++; + + array_length = tswap32( + *(const uint32_t *)(arg_struct + se->field_offsets[0][len_field_idx])); + arg_size = thunk_type_size(type_ptr, 0); + a = arg; + + if (*type_ptr == TYPE_CHAR) { + qemu_log("\""); + is_string = 1; + } else { + qemu_log("["); + } + + for (i = 0; i < array_length; i++) { + if (i > 0 && !is_string) { + qemu_log(","); + } + thunk_print(a, type_ptr); + a += arg_size; + } + + if (is_string) { + qemu_log("\""); + } else { + qemu_log("]"); + } + return thunk_type_next(type_ptr); +} + const argtype *thunk_print(void *arg, const argtype *type_ptr) { int type; @@ -414,17 +499,79 @@ const argtype *thunk_print(void *arg, const argtype *type_ptr) if (i > 0) { qemu_log(","); } + if (*field_types == TYPE_FLEXIBLE_ARRAY) { + field_types = thunk_print_flexible_array( + a + arg_offsets[i], a, field_types, se); + continue; + } field_types = thunk_print(a + arg_offsets[i], field_types); } qemu_log("}"); } break; + case TYPE_FLEXIBLE_ARRAY: + fprintf(stderr, + "Invalid flexible array (type 0x%x) outside of a structure\n", + type); + break; default: g_assert_not_reached(); } return type_ptr; } +bool thunk_type_has_flexible_array(const argtype *type_ptr) { + int i; + const StructEntry *se; + const argtype *field_types; + if (*type_ptr != TYPE_STRUCT) { + return false; + } + se = struct_entries + type_ptr[1]; + field_types = se->field_types; + for (i = 0; i < se->nb_fields; i++) { + if (*field_types == TYPE_FLEXIBLE_ARRAY) { + return true; + } + field_types = thunk_type_next(type_ptr); + } + return false; +} + +int thunk_type_size_with_src(const void *src, const argtype *type_ptr, + int is_host) +{ + switch(*type_ptr) { + case TYPE_STRUCT: { + int i; + const StructEntry *se = struct_entries + type_ptr[1]; + const argtype *field_types; + if (se->thunk_size[is_host] != NULL) { + return (*se->thunk_size[is_host])(src); + } + + field_types = se->field_types; + for (i = 0; i < se->nb_fields; i++) { + if (*field_types == TYPE_FLEXIBLE_ARRAY) { + uint32_t array_length = *(const uint32_t *)( + (const uint8_t*) src + + se->field_offsets[is_host][field_types[1]]); + if (!is_host) { + array_length = tswap32(array_length); + } + return se->size[is_host] + + array_length * + thunk_type_size(field_types + 2, is_host); + } + field_types = thunk_type_next(type_ptr); + } + return se->size[is_host]; + } + default: + return thunk_type_size(type_ptr, is_host); + } +} + /* from em86 */ /* Utility function: Table-driven functions to translate bitmasks