projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| e44c22f6 PA |
1 | /* -*- linux-c -*- ------------------------------------------------------- * |
| 2 | * | |
| 3 | * Copyright (C) 1991, 1992 Linus Torvalds | |
| 4 | * Copyright 2007 rPath, Inc. - All Rights Reserved | |
| 5 | * | |
| 6 | * This file is part of the Linux kernel, and is made available under | |
| 7 | * the terms of the GNU General Public License version 2. | |
| 8 | * | |
| 9 | * ----------------------------------------------------------------------- */ | |
| 10 | ||
| 11 | /* | |
| e44c22f6 PA |
12 | * Simple command-line parser for early boot. |
| 13 | */ | |
| 14 | ||
| 15 | #include "boot.h" | |
| 16 | ||
| 17 | static inline int myisspace(u8 c) | |
| 18 | { | |
| 19 | return c <= ' '; /* Close enough approximation */ | |
| 20 | } | |
| 21 | ||
| 22 | /* | |
| 23 | * Find a non-boolean option, that is, "option=argument". In accordance | |
| 24 | * with standard Linux practice, if this option is repeated, this returns | |
| 25 | * the last instance on the command line. | |
| 26 | * | |
| 27 | * Returns the length of the argument (regardless of if it was | |
| 28 | * truncated to fit in the buffer), or -1 on not found. | |
| 29 | */ | |
| 30 | int cmdline_find_option(const char *option, char *buffer, int bufsize) | |
| 31 | { | |
| 32 | u32 cmdline_ptr = boot_params.hdr.cmd_line_ptr; | |
| 33 | addr_t cptr; | |
| 34 | char c; | |
| 35 | int len = -1; | |
| 36 | const char *opptr = NULL; | |
| 37 | char *bufptr = buffer; | |
| 38 | enum { | |
| 39 | st_wordstart, /* Start of word/after whitespace */ | |
| 40 | st_wordcmp, /* Comparing this word */ | |
| 41 | st_wordskip, /* Miscompare, skip */ | |
| 42 | st_bufcpy /* Copying this to buffer */ | |
| 43 | } state = st_wordstart; | |
| 44 | ||
| 45 | if (!cmdline_ptr || cmdline_ptr >= 0x100000) | |
| 46 | return -1; /* No command line, or inaccessible */ | |
| 47 | ||
| 48 | cptr = cmdline_ptr & 0xf; | |
| 49 | set_fs(cmdline_ptr >> 4); | |
| 50 | ||
| 51 | while (cptr < 0x10000 && (c = rdfs8(cptr++))) { | |
| 52 | switch (state) { | |
| 53 | case st_wordstart: | |
| 54 | if (myisspace(c)) | |
| 55 | break; | |
| 56 | ||
| 57 | /* else */ | |
| 58 | state = st_wordcmp; | |
| 59 | opptr = option; | |
| 60 | /* fall through */ | |
| 61 | ||
| 62 | case st_wordcmp: | |
| 63 | if (c == '=' && !*opptr) { | |
| 64 | len = 0; | |
| 65 | bufptr = buffer; | |
| 66 | state = st_bufcpy; | |
| 67 | } else if (myisspace(c)) { | |
| 68 | state = st_wordstart; | |
| 69 | } else if (c != *opptr++) { | |
| 70 | state = st_wordskip; | |
| 71 | } | |
| 72 | break; | |
| 73 | ||
| 74 | case st_wordskip: | |
| 75 | if (myisspace(c)) | |
| 76 | state = st_wordstart; | |
| 77 | break; | |
| 78 | ||
| 79 | case st_bufcpy: | |
| 80 | if (myisspace(c)) { | |
| 81 | state = st_wordstart; | |
| 82 | } else { | |
| 83 | if (len < bufsize-1) | |
| 84 | *bufptr++ = c; | |
| 85 | len++; | |
| 86 | } | |
| 87 | break; | |
| 88 | } | |
| 89 | } | |
| 90 | ||
| 91 | if (bufsize) | |
| 92 | *bufptr = '\0'; | |
| 93 | ||
| 94 | return len; | |
| 95 | } | |
| 32d0b989 | 96 | |
| 97 | /* | |
| 98 | * Find a boolean option (like quiet,noapic,nosmp....) | |
| 99 | * | |
| 100 | * Returns the position of that option (starts counting with 1) | |
| 101 | * or 0 on not found | |
| 102 | */ | |
| 103 | int cmdline_find_option_bool(const char *option) | |
| 104 | { | |
| 105 | u32 cmdline_ptr = boot_params.hdr.cmd_line_ptr; | |
| 106 | addr_t cptr; | |
| 107 | char c; | |
| 70d8abf5 | 108 | int pos = 0, wstart = 0; |
| 32d0b989 | 109 | const char *opptr = NULL; |
| 110 | enum { | |
| 111 | st_wordstart, /* Start of word/after whitespace */ | |
| 112 | st_wordcmp, /* Comparing this word */ | |
| 113 | st_wordskip, /* Miscompare, skip */ | |
| 114 | } state = st_wordstart; | |
| 115 | ||
| 116 | if (!cmdline_ptr || cmdline_ptr >= 0x100000) | |
| 117 | return -1; /* No command line, or inaccessible */ | |
| 118 | ||
| 119 | cptr = cmdline_ptr & 0xf; | |
| 120 | set_fs(cmdline_ptr >> 4); | |
| 121 | ||
| 122 | while (cptr < 0x10000) { | |
| 123 | c = rdfs8(cptr++); | |
| 124 | pos++; | |
| 125 | ||
| 126 | switch (state) { | |
| 127 | case st_wordstart: | |
| 128 | if (!c) | |
| 129 | return 0; | |
| 130 | else if (myisspace(c)) | |
| 131 | break; | |
| 132 | ||
| 133 | state = st_wordcmp; | |
| 134 | opptr = option; | |
| 135 | wstart = pos; | |
| 136 | /* fall through */ | |
| 137 | ||
| 138 | case st_wordcmp: | |
| 139 | if (!*opptr) | |
| 140 | if (!c || myisspace(c)) | |
| 141 | return wstart; | |
| 142 | else | |
| 143 | state = st_wordskip; | |
| 144 | else if (!c) | |
| 145 | return 0; | |
| 146 | else if (c != *opptr++) | |
| 147 | state = st_wordskip; | |
| 148 | break; | |
| 149 | ||
| 150 | case st_wordskip: | |
| 151 | if (!c) | |
| 152 | return 0; | |
| 153 | else if (myisspace(c)) | |
| 154 | state = st_wordstart; | |
| 155 | break; | |
| 156 | } | |
| 157 | } | |
| 158 | ||
| 159 | return 0; /* Buffer overrun */ | |
| 160 | } |