From patchwork Tue Sep 25 14:55:56 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Renninger X-Patchwork-Id: 1504731 Return-Path: X-Original-To: patchwork-linux-acpi@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id 9FFF3DF24C for ; Tue, 25 Sep 2012 14:57:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756547Ab2IYO5E (ORCPT ); Tue, 25 Sep 2012 10:57:04 -0400 Received: from cantor2.suse.de ([195.135.220.15]:38685 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755952Ab2IYO43 (ORCPT ); Tue, 25 Sep 2012 10:56:29 -0400 Received: from relay2.suse.de (unknown [195.135.220.254]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx2.suse.de (Postfix) with ESMTP id 9D8BFA3E19; Tue, 25 Sep 2012 16:56:26 +0200 (CEST) From: Thomas Renninger To: hpa@zytor.com Cc: lenb@kernel.org, initramfs@vger.kernel.org, robert.moore@intel.com, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, yinghai@kernel.org, "H. Peter Anvin" , Thomas Renninger Subject: [PATCH 1/6] lib: Add early cpio decoder Date: Tue, 25 Sep 2012 16:55:56 +0200 Message-Id: <1348584961-1476-2-git-send-email-trenn@suse.de> X-Mailer: git-send-email 1.7.6.1 In-Reply-To: <1348584961-1476-1-git-send-email-trenn@suse.de> References: <1348584961-1476-1-git-send-email-trenn@suse.de> Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org From: "H. Peter Anvin" Add a simple cpio decoder without library dependencies for the purpose of extracting components from the initramfs blob for early kernel uses. Intended consumers so far are microcode and ACPI override. Signed-off-by: H. Peter Anvin CC: Thomas Renninger Link: http://lkml.kernel.org/r/201203261651.29640.trenn@suse.de Link: https://lkml.org/lkml/2012/9/21/190 Signed-off-by: Thomas Renninger --- include/linux/earlycpio.h | 17 +++++ lib/Makefile | 2 +- lib/earlycpio.c | 145 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 163 insertions(+), 1 deletions(-) create mode 100644 include/linux/earlycpio.h create mode 100644 lib/earlycpio.c diff --git a/include/linux/earlycpio.h b/include/linux/earlycpio.h new file mode 100644 index 0000000..111f46d --- /dev/null +++ b/include/linux/earlycpio.h @@ -0,0 +1,17 @@ +#ifndef _LINUX_EARLYCPIO_H +#define _LINUX_EARLYCPIO_H + +#include + +#define MAX_CPIO_FILE_NAME 18 + +struct cpio_data { + void *data; + size_t size; + char name[MAX_CPIO_FILE_NAME]; +}; + +struct cpio_data find_cpio_data(const char *path, void *data, size_t len, + long *offset); + +#endif /* _LINUX_EARLYCPIO_H */ diff --git a/lib/Makefile b/lib/Makefile index 42d283e..0924041 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -12,7 +12,7 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \ idr.o int_sqrt.o extable.o prio_tree.o \ sha1.o md5.o irq_regs.o reciprocal_div.o argv_split.o \ proportions.o flex_proportions.o prio_heap.o ratelimit.o show_mem.o \ - is_single_threaded.o plist.o decompress.o + is_single_threaded.o plist.o decompress.o earlycpio.o lib-$(CONFIG_MMU) += ioremap.o lib-$(CONFIG_SMP) += cpumask.o diff --git a/lib/earlycpio.c b/lib/earlycpio.c new file mode 100644 index 0000000..8078ef4 --- /dev/null +++ b/lib/earlycpio.c @@ -0,0 +1,145 @@ +/* ----------------------------------------------------------------------- * + * + * Copyright 2012 Intel Corporation; author H. Peter Anvin + * + * This file is part of the Linux kernel, and is made available + * under the terms of the GNU General Public License version 2, as + * published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * ----------------------------------------------------------------------- */ + +/* + * earlycpio.c + * + * Find a specific cpio member; must precede any compressed content. + * This is used to locate data items in the initramfs used by the + * kernel itself during early boot (before the main initramfs is + * decompressed.) It is the responsibility of the initramfs creator + * to ensure that these items are uncompressed at the head of the + * blob. Depending on the boot loader or package tool that may be a + * separate file or part of the same file. + */ + +#include +#include +#include + +enum cpio_fields { + C_MAGIC, + C_INO, + C_MODE, + C_UID, + C_GID, + C_NLINK, + C_MTIME, + C_FILESIZE, + C_MAJ, + C_MIN, + C_RMAJ, + C_RMIN, + C_NAMESIZE, + C_CHKSUM, + C_NFIELDS +}; + +/** + * cpio_data find_cpio_data - Search for files in an uncompressed cpio + * @path: The directory to search for, including a slash at the end + * @data: Pointer to the the cpio archive or a header inside + * @len: Remaining length of the cpio based on data pointer + * @offset: When a matching file is found, this is the offset to the + * beginning of the cpio. It can be used to iterate through + * the cpio to find all files inside of a directory path + * + * @return: struct cpio_data containing the address, length and + * filename (with the directory path cut off) of the found file. + * If you search for a filename and not for files in a directory, + * pass the absolute path of the filename in the cpio and make sure + * the match returned an empty filename string. + */ + +struct cpio_data __cpuinit find_cpio_data(const char *path, void *data, + size_t len, long *offset) +{ + const size_t cpio_header_len = 8*C_NFIELDS - 2; + struct cpio_data cd = { NULL, 0, "" }; + const char *p, *dptr, *nptr; + unsigned int ch[C_NFIELDS], *chp, v; + unsigned char c, x; + size_t mypathsize = strlen(path); + int i, j; + + p = data; + + while (len > cpio_header_len) { + if (!*p) { + /* All cpio headers need to be 4-byte aligned */ + p += 4; + len -= 4; + continue; + } + + j = 6; /* The magic field is only 6 characters */ + chp = ch; + for (i = C_NFIELDS; i; i--) { + v = 0; + while (j--) { + v <<= 4; + c = *p++; + + x = c - '0'; + if (x < 10) { + v += x; + continue; + } + + x = (c | 0x20) - 'a'; + if (x < 6) { + v += x + 10; + continue; + } + + goto quit; /* Invalid hexadecimal */ + } + *chp++ = v; + j = 8; /* All other fields are 8 characters */ + } + + if ((ch[C_MAGIC] - 0x070701) > 1) + goto quit; /* Invalid magic */ + + len -= cpio_header_len; + + dptr = PTR_ALIGN(p + ch[C_NAMESIZE], 4); + nptr = PTR_ALIGN(dptr + ch[C_FILESIZE], 4); + + if (nptr > p + len || dptr < p || nptr < dptr) + goto quit; /* Buffer overrun */ + + if ((ch[C_MODE] & 0170000) == 0100000 && + ch[C_NAMESIZE] >= mypathsize && + !memcmp(p, path, mypathsize)) { + *offset = (long)nptr - (long)data; + if (ch[C_NAMESIZE] - mypathsize >= MAX_CPIO_FILE_NAME) { + pr_warn( + "File %s exceeding MAX_CPIO_FILE_NAME [%d]\n", + p, MAX_CPIO_FILE_NAME); + } + strlcpy(cd.name, p + mypathsize, MAX_CPIO_FILE_NAME); + + cd.data = (void *)dptr; + cd.size = ch[C_FILESIZE]; + return cd; /* Found it! */ + } + len -= (nptr - p); + p = nptr; + } + +quit: + return cd; +}