mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-19 18:24:14 +08:00
1b1ded57a4
Carve out early cmdline parsing function into .../lib/cmdline.c so it can be used by early code in the kernel proper as well. Adapted from arch/x86/boot/cmdline.c. Signed-off-by: Borislav Petkov <bp@suse.de> Link: http://lkml.kernel.org/r/1400525957-11525-2-git-send-email-bp@alien8.de Signed-off-by: H. Peter Anvin <hpa@zytor.com>
85 lines
1.7 KiB
C
85 lines
1.7 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.
|
|
*/
|
|
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 */
|
|
}
|