-
Notifications
You must be signed in to change notification settings - Fork 0
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
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 <hpa@linux.intel.com> Link: http://lkml.kernel.org/r/1349043837-22659-2-git-send-email-trenn@suse.de Cc: Len Brown <lenb@kernel.org> Cc: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Thomas Renninger <trenn@suse.de> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
- Loading branch information
H. Peter Anvin
committed
Oct 1, 2012
1 parent
979570e
commit e645960
Showing
3 changed files
with
163 additions
and
1 deletion.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,17 @@ | ||
#ifndef _LINUX_EARLYCPIO_H | ||
#define _LINUX_EARLYCPIO_H | ||
|
||
#include <linux/types.h> | ||
|
||
#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 */ |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -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 <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 | ||
}; | ||
|
||
/** | ||
* 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; | ||
} |