mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-12 13:55:32 +00:00
![Gustavo A. R. Silva](/assets/img/avatar_default.png)
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
214 lines
4.7 KiB
C
214 lines
4.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
*
|
|
* 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;
|
|
fallthrough;
|
|
|
|
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;
|
|
fallthrough;
|
|
|
|
case st_wordskip:
|
|
if (!c)
|
|
return 0;
|
|
else if (myisspace(c))
|
|
state = st_wordstart;
|
|
break;
|
|
}
|
|
}
|
|
|
|
return 0; /* Buffer overrun */
|
|
}
|
|
|
|
/*
|
|
* Find a non-boolean option (i.e. option=argument). In accordance with
|
|
* standard Linux practice, if this option is repeated, this returns the
|
|
* last instance on the command line.
|
|
*
|
|
* @cmdline: the cmdline string
|
|
* @max_cmdline_size: the maximum size of cmdline
|
|
* @option: option string to look for
|
|
* @buffer: memory buffer to return the option argument
|
|
* @bufsize: size of the supplied memory buffer
|
|
*
|
|
* Returns the length of the argument (regardless of if it was
|
|
* truncated to fit in the buffer), or -1 on not found.
|
|
*/
|
|
static int
|
|
__cmdline_find_option(const char *cmdline, int max_cmdline_size,
|
|
const char *option, char *buffer, int bufsize)
|
|
{
|
|
char c;
|
|
int pos = 0, len = -1;
|
|
const char *opptr = NULL;
|
|
char *bufptr = buffer;
|
|
enum {
|
|
st_wordstart = 0, /* 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)
|
|
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++;
|
|
if (!c)
|
|
break;
|
|
|
|
switch (state) {
|
|
case st_wordstart:
|
|
if (myisspace(c))
|
|
break;
|
|
|
|
state = st_wordcmp;
|
|
opptr = option;
|
|
fallthrough;
|
|
|
|
case st_wordcmp:
|
|
if ((c == '=') && !*opptr) {
|
|
/*
|
|
* We matched all the way to the end of the
|
|
* option we were looking for, prepare to
|
|
* copy the argument.
|
|
*/
|
|
len = 0;
|
|
bufptr = buffer;
|
|
state = st_bufcpy;
|
|
break;
|
|
} else if (c == *opptr++) {
|
|
/*
|
|
* We are currently matching, so continue
|
|
* to the next character on the cmdline.
|
|
*/
|
|
break;
|
|
}
|
|
state = st_wordskip;
|
|
fallthrough;
|
|
|
|
case st_wordskip:
|
|
if (myisspace(c))
|
|
state = st_wordstart;
|
|
break;
|
|
|
|
case st_bufcpy:
|
|
if (myisspace(c)) {
|
|
state = st_wordstart;
|
|
} else {
|
|
/*
|
|
* Increment len, but don't overrun the
|
|
* supplied buffer and leave room for the
|
|
* NULL terminator.
|
|
*/
|
|
if (++len < bufsize)
|
|
*bufptr++ = c;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (bufsize)
|
|
*bufptr = '\0';
|
|
|
|
return len;
|
|
}
|
|
|
|
int cmdline_find_option_bool(const char *cmdline, const char *option)
|
|
{
|
|
return __cmdline_find_option_bool(cmdline, COMMAND_LINE_SIZE, option);
|
|
}
|
|
|
|
int cmdline_find_option(const char *cmdline, const char *option, char *buffer,
|
|
int bufsize)
|
|
{
|
|
return __cmdline_find_option(cmdline, COMMAND_LINE_SIZE, option,
|
|
buffer, bufsize);
|
|
}
|