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/*
* This file is part of the Linux kernel, and is made available under
* the terms of the GNU General Public License version 2.
*
* Misc librarized functions for cmdline poking.
*/
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <asm/setup.h>
static inline int myisspace(u8 c)
{
return c <= ' '; /* Close enough approximation */
}
/**
* Find a boolean option (like quiet,noapic,nosmp....)
*
* @cmdline: the cmdline string
* @option: option string to look for
*
* Returns the position of that @option (starts counting with 1)
* or 0 on not found.
*/
int cmdline_find_option_bool(const char *cmdline, const char *option)
{
char c;
int len, pos = 0, wstart = 0;
const char *opptr = NULL;
enum {
st_wordstart = 0, /* Start of word/after whitespace */
st_wordcmp, /* Comparing this word */
st_wordskip, /* Miscompare, skip */
} state = st_wordstart;
if (!cmdline)
return -1; /* No command line */
len = min_t(int, strlen(cmdline), COMMAND_LINE_SIZE);
if (!len)
return 0;
while (len--) {
c = *(char *)cmdline++;
pos++;
switch (state) {
case st_wordstart:
if (!c)
return 0;
else if (myisspace(c))
break;
state = st_wordcmp;
opptr = option;
wstart = pos;
/* fall through */
case st_wordcmp:
if (!*opptr)
if (!c || myisspace(c))
return wstart;
else
state = st_wordskip;
else if (!c)
return 0;
else if (c != *opptr++)
state = st_wordskip;
else if (!len) /* last word and is matching */
return wstart;
break;
case st_wordskip:
if (!c)
return 0;
else if (myisspace(c))
state = st_wordstart;
break;
}
}
return 0; /* Buffer overrun */
}
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