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/*
* Copyright (C) 2021 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
FILE_LICENCE ( GPL2_OR_LATER );
#include <string.h>
#include <errno.h>
#include <ipxe/umalloc.h>
#include <ipxe/linux_api.h>
#include <ipxe/linux.h>
#include <ipxe/linux_sysfs.h>
/** @file
*
* Linux sysfs files
*
*/
/** Read blocksize */
#define LINUX_SYSFS_BLKSIZE 4096
/**
* Read file from sysfs
*
* @v filename Filename
* @v data Data to fill in
* @ret len Length read, or negative error
*/
int linux_sysfs_read ( const char *filename, userptr_t *data ) {
userptr_t tmp;
ssize_t read;
size_t len;
int fd;
int rc;
/* Open file */
fd = linux_open ( filename, O_RDONLY );
if ( fd < 0 ) {
rc = -ELINUX ( linux_errno );
DBGC ( filename, "LINUX could not open %s: %s\n",
filename, linux_strerror ( linux_errno ) );
goto err_open;
}
/* Read file */
for ( *data = UNULL, len = 0 ; ; len += read ) {
/* (Re)allocate space */
tmp = urealloc ( *data, ( len + LINUX_SYSFS_BLKSIZE ) );
if ( ! tmp ) {
rc = -ENOMEM;
goto err_alloc;
}
*data = tmp;
/* Read from file */
read = linux_read ( fd, user_to_virt ( *data, len ),
LINUX_SYSFS_BLKSIZE );
if ( read == 0 )
break;
if ( read < 0 ) {
DBGC ( filename, "LINUX could not read %s: %s\n",
filename, linux_strerror ( linux_errno ) );
goto err_read;
}
}
/* Close file */
linux_close ( fd );
DBGC ( filename, "LINUX read %s\n", filename );
return len;
err_read:
err_alloc:
ufree ( *data );
linux_close ( fd );
err_open:
return rc;
}
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