mirror of
https://github.com/torvalds/linux
synced 2024-11-05 18:23:50 +00:00
96ae6ea0be
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
97 lines
2.1 KiB
C
97 lines
2.1 KiB
C
/* -*- 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;
|
|
}
|