2 * This file is part of the Linux kernel, and is made available under
3 * the terms of the GNU General Public License version 2.
5 * Misc librarized functions for cmdline poking.
7 #include <linux/kernel.h>
8 #include <linux/string.h>
9 #include <linux/ctype.h>
10 #include <asm/setup.h>
12 static inline int myisspace(u8 c)
14 return c <= ' '; /* Close enough approximation */
18 * Find a boolean option (like quiet,noapic,nosmp....)
20 * @cmdline: the cmdline string
21 * @option: option string to look for
23 * Returns the position of that @option (starts counting with 1)
24 * or 0 on not found. @option will only be found if it is found
25 * as an entire word in @cmdline. For instance, if @option="car"
26 * then a cmdline which contains "cart" will not match.
29 __cmdline_find_option_bool(const char *cmdline, int max_cmdline_size,
33 int pos = 0, wstart = 0;
34 const char *opptr = NULL;
36 st_wordstart = 0, /* Start of word/after whitespace */
37 st_wordcmp, /* Comparing this word */
38 st_wordskip, /* Miscompare, skip */
39 } state = st_wordstart;
42 return -1; /* No command line */
45 * This 'pos' check ensures we do not overrun
46 * a non-NULL-terminated 'cmdline'
48 while (pos < max_cmdline_size) {
49 c = *(char *)cmdline++;
56 else if (myisspace(c))
67 * We matched all the way to the end of the
68 * option we were looking for. If the
69 * command-line has a space _or_ ends, then
72 if (!c || myisspace(c))
75 * We hit the end of the option, but _not_
76 * the end of a word on the cmdline. Not
81 * Hit the NULL terminator on the end of
85 } else if (c == *opptr++) {
87 * We are currently matching, so continue
88 * to the next character on the cmdline.
98 else if (myisspace(c))
104 return 0; /* Buffer overrun */
107 int cmdline_find_option_bool(const char *cmdline, const char *option)
109 return __cmdline_find_option_bool(cmdline, COMMAND_LINE_SIZE, option);