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Based on 1 normalized pattern(s): this file is part of the linux kernel and is made available under the terms of the gnu general public license version 2 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 28 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.534229504@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
214 lines
4.7 KiB
C
214 lines
4.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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*
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* Misc librarized functions for cmdline poking.
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*/
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/ctype.h>
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#include <asm/setup.h>
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static inline int myisspace(u8 c)
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{
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return c <= ' '; /* Close enough approximation */
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}
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/**
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* Find a boolean option (like quiet,noapic,nosmp....)
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*
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* @cmdline: the cmdline string
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* @option: option string to look for
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*
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* Returns the position of that @option (starts counting with 1)
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* or 0 on not found. @option will only be found if it is found
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* as an entire word in @cmdline. For instance, if @option="car"
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* then a cmdline which contains "cart" will not match.
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*/
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static int
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__cmdline_find_option_bool(const char *cmdline, int max_cmdline_size,
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const char *option)
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{
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char c;
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int pos = 0, wstart = 0;
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const char *opptr = NULL;
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enum {
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st_wordstart = 0, /* Start of word/after whitespace */
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st_wordcmp, /* Comparing this word */
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st_wordskip, /* Miscompare, skip */
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} state = st_wordstart;
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if (!cmdline)
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return -1; /* No command line */
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/*
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* This 'pos' check ensures we do not overrun
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* a non-NULL-terminated 'cmdline'
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*/
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while (pos < max_cmdline_size) {
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c = *(char *)cmdline++;
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pos++;
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switch (state) {
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case st_wordstart:
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if (!c)
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return 0;
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else if (myisspace(c))
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break;
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state = st_wordcmp;
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opptr = option;
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wstart = pos;
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/* fall through */
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case st_wordcmp:
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if (!*opptr) {
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/*
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* We matched all the way to the end of the
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* option we were looking for. If the
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* command-line has a space _or_ ends, then
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* we matched!
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*/
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if (!c || myisspace(c))
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return wstart;
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/*
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* We hit the end of the option, but _not_
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* the end of a word on the cmdline. Not
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* a match.
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*/
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} else if (!c) {
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/*
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* Hit the NULL terminator on the end of
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* cmdline.
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*/
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return 0;
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} else if (c == *opptr++) {
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/*
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* We are currently matching, so continue
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* to the next character on the cmdline.
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*/
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break;
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}
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state = st_wordskip;
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/* fall through */
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case st_wordskip:
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if (!c)
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return 0;
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else if (myisspace(c))
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state = st_wordstart;
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break;
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}
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}
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return 0; /* Buffer overrun */
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}
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/*
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* Find a non-boolean option (i.e. option=argument). In accordance with
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* standard Linux practice, if this option is repeated, this returns the
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* last instance on the command line.
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*
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* @cmdline: the cmdline string
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* @max_cmdline_size: the maximum size of cmdline
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* @option: option string to look for
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* @buffer: memory buffer to return the option argument
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* @bufsize: size of the supplied memory buffer
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*
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* Returns the length of the argument (regardless of if it was
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* truncated to fit in the buffer), or -1 on not found.
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*/
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static int
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__cmdline_find_option(const char *cmdline, int max_cmdline_size,
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const char *option, char *buffer, int bufsize)
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{
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char c;
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int pos = 0, len = -1;
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const char *opptr = NULL;
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char *bufptr = buffer;
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enum {
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st_wordstart = 0, /* Start of word/after whitespace */
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st_wordcmp, /* Comparing this word */
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st_wordskip, /* Miscompare, skip */
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st_bufcpy, /* Copying this to buffer */
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} state = st_wordstart;
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if (!cmdline)
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return -1; /* No command line */
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/*
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* This 'pos' check ensures we do not overrun
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* a non-NULL-terminated 'cmdline'
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*/
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while (pos++ < max_cmdline_size) {
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c = *(char *)cmdline++;
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if (!c)
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break;
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switch (state) {
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case st_wordstart:
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if (myisspace(c))
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break;
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state = st_wordcmp;
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opptr = option;
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/* fall through */
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case st_wordcmp:
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if ((c == '=') && !*opptr) {
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/*
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* We matched all the way to the end of the
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* option we were looking for, prepare to
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* copy the argument.
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*/
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len = 0;
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bufptr = buffer;
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state = st_bufcpy;
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break;
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} else if (c == *opptr++) {
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/*
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* We are currently matching, so continue
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* to the next character on the cmdline.
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*/
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break;
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}
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state = st_wordskip;
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/* fall through */
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case st_wordskip:
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if (myisspace(c))
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state = st_wordstart;
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break;
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case st_bufcpy:
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if (myisspace(c)) {
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state = st_wordstart;
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} else {
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/*
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* Increment len, but don't overrun the
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* supplied buffer and leave room for the
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* NULL terminator.
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*/
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if (++len < bufsize)
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*bufptr++ = c;
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}
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break;
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}
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}
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if (bufsize)
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*bufptr = '\0';
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return len;
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}
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int cmdline_find_option_bool(const char *cmdline, const char *option)
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{
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return __cmdline_find_option_bool(cmdline, COMMAND_LINE_SIZE, option);
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}
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int cmdline_find_option(const char *cmdline, const char *option, char *buffer,
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int bufsize)
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{
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return __cmdline_find_option(cmdline, COMMAND_LINE_SIZE, option,
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buffer, bufsize);
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}
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