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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142// SPDX-License-Identifier: GPL-2.0-only/* ----------------------------------------------------------------------- * * * Copyright 2012 Intel Corporation; author H. Peter Anvin * * ----------------------------------------------------------------------- */
/* * 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 <linux/earlycpio.h>#include <linux/kernel.h>#include <linux/string.h>
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};
/** * 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 cpio archive or a header inside * @len: Remaining length of the cpio based on data pointer * @nextoff: When a matching file is found, this is the offset from the * beginning of the cpio to the beginning of the next file, not the * matching file itself. 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 find_cpio_data(const char *path, void *data, size_t len, long *nextoff){ 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)) {
if (nextoff) *nextoff = (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); } strscpy(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;}