From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from terminus.zytor.com ([192.83.249.54]:50694 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754334AbXGJDcZ (ORCPT ); Mon, 9 Jul 2007 23:32:25 -0400 From: "H. Peter Anvin" Subject: [x86 setup 19/33] Command-line parsing code for the new x86 setup code Date: Mon, 9 Jul 2007 19:51:58 -0700 Message-Id: <11840379311574-git-send-email-hpa@zytor.com> In-Reply-To: <11840378261081-git-send-email-hpa@zytor.com> References: <11840359321823-git-send-email-hpa@zytor.com> <11840360383913-git-send-email-hpa@zytor.com> <11840361432207-git-send-email-hpa@zytor.com> <11840362483663-git-send-email-hpa@zytor.com> <11840363531039-git-send-email-hpa@zytor.com> <11840364593068-git-send-email-hpa@zytor.com> <1184036564610-git-send-email-hpa@zytor.com> <11840366692770-git-send-email-hpa@zytor.com> <11840367741994-git-send-email-hpa@zytor.com> <11840368791603-git-send-email-hpa@zytor.com> <11840369841576-git-send-email-hpa@zytor.com> <11840370903975-git-send-email-hpa@zytor.com> <11840371953778-git-send-email-hpa@zytor.com> <11840373002601-git-send-email-hpa@zytor.com> <11840374052662-git-send-email-hpa@zytor.com> <1184037510289-git-send-email-hpa@zytor.com> <11840376162370-git-send-email-hpa@zytor.com> <11840377211519-git-send-email-hpa@zytor.com> <11840378261081-git-send-email-hpa@zytor.com> Message-Id: <3726c75f36dc97c1fce93835e872bbc814857990.1184032749.git.hpa@zytor.com> In-Reply-To: <2034f71d414def30de582fb59573295cadbdabb4.1184032748.git.hpa@zytor.com> References: <2034f71d414def30de582fb59573295cadbdabb4.1184032748.git.hpa@zytor.com> Sender: linux-arch-owner@vger.kernel.org To: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, andi@firstfloor.org, akpm@linux-foundation.org Cc: "H. Peter Anvin" List-ID: From: H. Peter Anvin Simple command-line parser which allows us to access the kernel command line from the setup code. Signed-off-by: H. Peter Anvin --- arch/i386/boot/cmdline.c | 97 ++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 97 insertions(+), 0 deletions(-) create mode 100644 arch/i386/boot/cmdline.c diff --git a/arch/i386/boot/cmdline.c b/arch/i386/boot/cmdline.c new file mode 100644 index 0000000..34bb778 --- /dev/null +++ b/arch/i386/boot/cmdline.c @@ -0,0 +1,97 @@ +/* -*- linux-c -*- ------------------------------------------------------- * + * + * Copyright (C) 1991, 1992 Linus Torvalds + * Copyright 2007 rPath, Inc. - All Rights Reserved + * + * This file is part of the Linux kernel, and is made available under + * the terms of the GNU General Public License version 2. + * + * ----------------------------------------------------------------------- */ + +/* + * arch/i386/boot/cmdline.c + * + * Simple command-line parser for early boot. + */ + +#include "boot.h" + +static inline int myisspace(u8 c) +{ + return c <= ' '; /* Close enough approximation */ +} + +/* + * Find a non-boolean option, that is, "option=argument". In accordance + * with standard Linux practice, if this option is repeated, this returns + * the last instance on the command line. + * + * Returns the length of the argument (regardless of if it was + * truncated to fit in the buffer), or -1 on not found. + */ +int cmdline_find_option(const char *option, char *buffer, int bufsize) +{ + u32 cmdline_ptr = boot_params.hdr.cmd_line_ptr; + addr_t cptr; + char c; + int len = -1; + const char *opptr = NULL; + char *bufptr = buffer; + enum { + st_wordstart, /* Start of word/after whitespace */ + st_wordcmp, /* Comparing this word */ + st_wordskip, /* Miscompare, skip */ + st_bufcpy /* Copying this to buffer */ + } state = st_wordstart; + + if (!cmdline_ptr || cmdline_ptr >= 0x100000) + return -1; /* No command line, or inaccessible */ + + cptr = cmdline_ptr & 0xf; + set_fs(cmdline_ptr >> 4); + + while (cptr < 0x10000 && (c = rdfs8(cptr++))) { + switch (state) { + case st_wordstart: + if (myisspace(c)) + break; + + /* else */ + state = st_wordcmp; + opptr = option; + /* fall through */ + + case st_wordcmp: + if (c == '=' && !*opptr) { + len = 0; + bufptr = buffer; + state = st_bufcpy; + } else if (myisspace(c)) { + state = st_wordstart; + } else if (c != *opptr++) { + state = st_wordskip; + } + break; + + case st_wordskip: + if (myisspace(c)) + state = st_wordstart; + break; + + case st_bufcpy: + if (myisspace(c)) { + state = st_wordstart; + } else { + if (len < bufsize-1) + *bufptr++ = c; + len++; + } + break; + } + } + + if (bufsize) + *bufptr = '\0'; + + return len; +} -- 1.5.2.2