diff options
| -rw-r--r-- | arch/x86/boot/cmdline.c | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/arch/x86/boot/cmdline.c b/arch/x86/boot/cmdline.c index 34bb778c4357..cc65a33bf65c 100644 --- a/arch/x86/boot/cmdline.c +++ b/arch/x86/boot/cmdline.c @@ -95,3 +95,68 @@ int cmdline_find_option(const char *option, char *buffer, int bufsize) return len; } + +/* + * Find a boolean option (like quiet,noapic,nosmp....) + * + * Returns the position of that option (starts counting with 1) + * or 0 on not found + */ +int cmdline_find_option_bool(const char *option) +{ + u32 cmdline_ptr = boot_params.hdr.cmd_line_ptr; + addr_t cptr; + char c; + int pos =0 , wstart = 0; + const char *opptr = NULL; + enum { + st_wordstart, /* Start of word/after whitespace */ + st_wordcmp, /* Comparing this word */ + st_wordskip, /* Miscompare, skip */ + } state = st_wordstart; + + if (!cmdline_ptr || cmdline_ptr >= 0x100000) + return -1; /* No command line, or inaccessible */ + + cptr = cmdline_ptr & 0xf; + set_fs(cmdline_ptr >> 4); + + while (cptr < 0x10000) { + c = rdfs8(cptr++); + 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; + break; + + case st_wordskip: + if (!c) + return 0; + else if (myisspace(c)) + state = st_wordstart; + break; + } + } + + return 0; /* Buffer overrun */ +} |