linux/arch/x86/lib/cmdline.c
Dave Hansen 8c0517759a x86/boot: Pass in size to early cmdline parsing
We will use this in a few patches to implement tests for early parsing.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
[ Aligned args properly. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: fenghua.yu@intel.com
Cc: yu-cheng.yu@intel.com
Link: http://lkml.kernel.org/r/20151222225243.5CC47EB6@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-03 12:03:18 +01:00

111 lines
2.4 KiB
C

/*
* 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. @option will only be found if it is found
* as an entire word in @cmdline. For instance, if @option="car"
* then a cmdline which contains "cart" will not match.
*/
static int
__cmdline_find_option_bool(const char *cmdline, int max_cmdline_size,
const char *option)
{
char c;
int 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 */
/*
* This 'pos' check ensures we do not overrun
* a non-NULL-terminated 'cmdline'
*/
while (pos < max_cmdline_size) {
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) {
/*
* We matched all the way to the end of the
* option we were looking for. If the
* command-line has a space _or_ ends, then
* we matched!
*/
if (!c || myisspace(c))
return wstart;
/*
* We hit the end of the option, but _not_
* the end of a word on the cmdline. Not
* a match.
*/
} else if (!c) {
/*
* Hit the NULL terminator on the end of
* cmdline.
*/
return 0;
} else if (c == *opptr++) {
/*
* We are currently matching, so continue
* to the next character on the cmdline.
*/
break;
}
state = st_wordskip;
/* fall through */
case st_wordskip:
if (!c)
return 0;
else if (myisspace(c))
state = st_wordstart;
break;
}
}
return 0; /* Buffer overrun */
}
int cmdline_find_option_bool(const char *cmdline, const char *option)
{
return __cmdline_find_option_bool(cmdline, COMMAND_LINE_SIZE, option);
}