From patchwork Thu Jan 25 03:27:42 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Taras Kondratiuk X-Patchwork-Id: 10183593 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id BB6AD60383 for ; Thu, 25 Jan 2018 03:41:45 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AACDC283BD for ; Thu, 25 Jan 2018 03:41:45 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9B12428673; Thu, 25 Jan 2018 03:41:45 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.5 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,RCVD_IN_DNSWL_HI,USER_IN_DEF_DKIM_WL autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F2319283BD for ; Thu, 25 Jan 2018 03:41:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933497AbeAYDk5 (ORCPT ); Wed, 24 Jan 2018 22:40:57 -0500 Received: from alln-iport-3.cisco.com ([173.37.142.90]:38659 "EHLO alln-iport-3.cisco.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933374AbeAYDha (ORCPT ); Wed, 24 Jan 2018 22:37:30 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cisco.com; i=@cisco.com; l=5648; q=dns/txt; s=iport; t=1516851450; x=1518061050; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=kPtfKRZKS/cOHG4AIpt4bEc+kdJD6gX/yiPBjFXhWw4=; b=Mio1CcepFKBICFnIaM0a0JIUZi1tG9KGnvU71v8x4X1YkAzTwE/vee0Z qZvvxhsZGAjYzOgAS2jOdhKEkL45LLzDWGkbX585OqJF+fYgVTYrGad57 JabVNOJJvYZycRYhMce15y4hHbuW2v4wqqfuTlCsS7F06N6yflVD08/gH Y=; X-IronPort-AV: E=Sophos;i="5.46,409,1511827200"; d="scan'208";a="61438447" Received: from rcdn-core-6.cisco.com ([173.37.93.157]) by alln-iport-3.cisco.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 25 Jan 2018 03:27:59 +0000 Received: from sjc-ads-7132.cisco.com (sjc-ads-7132.cisco.com [10.30.217.207]) (authenticated bits=0) by rcdn-core-6.cisco.com (8.14.5/8.14.5) with ESMTP id w0P3Ruir007601 (version=TLSv1/SSLv3 cipher=AES128-SHA256 bits=128 verify=NO); Thu, 25 Jan 2018 03:27:58 GMT From: Taras Kondratiuk To: "H. Peter Anvin" , Al Viro , Arnd Bergmann , Rob Landley , Mimi Zohar , Jonathan Corbet , James McMechan Cc: initramfs@vger.kernel.org, Victor Kamensky , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, xe-linux-external@cisco.com Subject: [PATCH v2 02/15] initramfs: replace states with function pointers Date: Thu, 25 Jan 2018 03:27:42 +0000 Message-Id: <1516850875-25066-3-git-send-email-takondra@cisco.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1516850875-25066-1-git-send-email-takondra@cisco.com> References: <1516850875-25066-1-git-send-email-takondra@cisco.com> X-Auto-Response-Suppress: DR, OOF, AutoReply X-Authenticated-User: takondra@cisco.com Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP Currently the FSM states are mapped directly to function pointers. Extra level of intirection is not needed and makes navigation over the code harder. One can't jump between states directly when browsing code (e.g. with cscope). Need to go through actions[] array each time. Replace states with their action function pointers. No behaviour change. Signed-off-by: Taras Kondratiuk --- init/initramfs.c | 73 +++++++++++++++++++++++++------------------------------- 1 file changed, 32 insertions(+), 41 deletions(-) diff --git a/init/initramfs.c b/init/initramfs.c index 7e99a0038942..49cd2681a26f 100644 --- a/init/initramfs.c +++ b/init/initramfs.c @@ -187,16 +187,17 @@ static void __init parse_header(char *s) /* FSM */ -static __initdata enum state { - Start, - Collect, - GotHeader, - SkipIt, - GotName, - CopyFile, - GotSymlink, - Reset -} state, next_state; +static int __init do_start(void); +static int __init do_collect(void); +static int __init do_header(void); +static int __init do_skip(void); +static int __init do_name(void); +static int __init do_copy(void); +static int __init do_symlink(void); +static int __init do_reset(void); + +typedef int (*fsm_state_t)(void); +static __initdata fsm_state_t state, next_state; static __initdata char *victim; static unsigned long byte_count __initdata; @@ -214,7 +215,7 @@ static __initdata char *collected; static long remains __initdata; static __initdata char *collect; -static void __init read_into(char *buf, unsigned size, enum state next) +static void __init read_into(char *buf, unsigned size, fsm_state_t next) { if (byte_count >= size) { collected = victim; @@ -224,7 +225,7 @@ static void __init read_into(char *buf, unsigned size, enum state next) collect = collected = buf; remains = size; next_state = next; - state = Collect; + state = do_collect; } } @@ -232,7 +233,7 @@ static __initdata char *header_buf, *symlink_buf, *name_buf; static int __init do_start(void) { - read_into(header_buf, 110, GotHeader); + read_into(header_buf, 110, do_header); return 0; } @@ -263,7 +264,7 @@ static int __init do_header(void) parse_header(collected); next_header = this_header + N_ALIGN(name_len) + body_len; next_header = (next_header + 3) & ~3; - state = SkipIt; + state = do_skip; if (name_len <= 0 || name_len > PATH_MAX) return 0; if (S_ISLNK(mode)) { @@ -271,12 +272,12 @@ static int __init do_header(void) return 0; collect = collected = symlink_buf; remains = N_ALIGN(name_len) + body_len; - next_state = GotSymlink; - state = Collect; + next_state = do_symlink; + state = do_collect; return 0; } if (S_ISREG(mode) || !body_len) - read_into(name_buf, N_ALIGN(name_len), GotName); + read_into(name_buf, N_ALIGN(name_len), do_name); return 0; } @@ -327,8 +328,8 @@ static __initdata int wfd; static int __init do_name(void) { - state = SkipIt; - next_state = Reset; + state = do_skip; + next_state = do_reset; if (strcmp(collected, "TRAILER!!!") == 0) { free_hash(); return 0; @@ -348,7 +349,7 @@ static int __init do_name(void) if (body_len) sys_ftruncate(wfd, body_len); vcollected = kstrdup(collected, GFP_KERNEL); - state = CopyFile; + state = do_copy; } } } else if (S_ISDIR(mode)) { @@ -377,7 +378,7 @@ static int __init do_copy(void) do_utime(vcollected, mtime); kfree(vcollected); eat(body_len); - state = SkipIt; + state = do_skip; return 0; } else { if (xwrite(wfd, victim, byte_count) != byte_count) @@ -395,29 +396,19 @@ static int __init do_symlink(void) sys_symlink(collected + N_ALIGN(name_len), collected); sys_lchown(collected, uid, gid); do_utime(collected, mtime); - state = SkipIt; - next_state = Reset; + state = do_skip; + next_state = do_reset; return 0; } -static __initdata int (*actions[])(void) = { - [Start] = do_start, - [Collect] = do_collect, - [GotHeader] = do_header, - [SkipIt] = do_skip, - [GotName] = do_name, - [CopyFile] = do_copy, - [GotSymlink] = do_symlink, - [Reset] = do_reset, -}; - static long __init write_buffer(char *buf, unsigned long len) { byte_count = len; victim = buf; - while (!actions[state]()) - ; + do + pr_debug("state: %pf\n", state); + while (!state()); return len - byte_count; } @@ -433,11 +424,11 @@ static long __init flush_buffer(void *bufv, unsigned long len) if (c == '0') { buf += written; len -= written; - state = Start; + state = do_start; } else if (c == 0) { buf += written; len -= written; - state = Reset; + state = do_reset; } else error("junk in compressed archive"); } @@ -462,13 +453,13 @@ static char * __init unpack_to_rootfs(char *buf, unsigned long len) if (!header_buf || !symlink_buf || !name_buf) panic("can't allocate buffers"); - state = Start; + state = do_start; this_header = 0; message = NULL; while (!message && len) { loff_t saved_offset = this_header; if (*buf == '0' && !(this_header & 3)) { - state = Start; + state = do_start; written = write_buffer(buf, len); buf += written; len -= written; @@ -497,7 +488,7 @@ static char * __init unpack_to_rootfs(char *buf, unsigned long len) } } else error("junk in compressed archive"); - if (state != Reset) + if (state != do_reset) error("junk in compressed archive"); this_header = saved_offset + my_inptr; buf += my_inptr;