85 lines
1.7 KiB
C
85 lines
1.7 KiB
C
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/*
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* This file is part of the Linux kernel, and is made available under
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* the terms of the GNU General Public License version 2.
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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.
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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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char c;
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int len, 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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len = min_t(int, strlen(cmdline), COMMAND_LINE_SIZE);
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if (!len)
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return 0;
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while (len--) {
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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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if (!c || myisspace(c))
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return wstart;
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else
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state = st_wordskip;
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else if (!c)
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return 0;
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else if (c != *opptr++)
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state = st_wordskip;
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else if (!len) /* last word and is matching */
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return wstart;
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break;
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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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