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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 | // SPDX-License-Identifier: GPL-2.0-only /* -*- linux-c -*- ------------------------------------------------------- * * * Copyright (C) 1991, 1992 Linus Torvalds * Copyright 2007 rPath, Inc. - All Rights Reserved * * ----------------------------------------------------------------------- */ /* * Simple command-line parser for early boot. */ #include "boot.h" static inline int myisspace(u8 c) { return c <= ' '; /* Close enough approximation */ } /* * Find a non-boolean option, that is, "option=argument". In accordance * with standard Linux practice, if this option is repeated, this returns * the last instance on the command line. * * Returns the length of the argument (regardless of if it was * truncated to fit in the buffer), or -1 on not found. */ int __cmdline_find_option(unsigned long cmdline_ptr, const char *option, char *buffer, int bufsize) { addr_t cptr; char c; int len = -1; const char *opptr = NULL; char *bufptr = buffer; enum { st_wordstart, /* Start of word/after whitespace */ st_wordcmp, /* Comparing this word */ st_wordskip, /* Miscompare, skip */ st_bufcpy /* Copying this to buffer */ } state = st_wordstart; if (!cmdline_ptr) return -1; /* No command line */ cptr = cmdline_ptr & 0xf; set_fs(cmdline_ptr >> 4); while (cptr < 0x10000 && (c = rdfs8(cptr++))) { switch (state) { case st_wordstart: if (myisspace(c)) break; /* else */ state = st_wordcmp; opptr = option; fallthrough; case st_wordcmp: if (c == '=' && !*opptr) { len = 0; bufptr = buffer; state = st_bufcpy; } else if (myisspace(c)) { state = st_wordstart; } else if (c != *opptr++) { state = st_wordskip; } break; case st_wordskip: if (myisspace(c)) state = st_wordstart; break; case st_bufcpy: if (myisspace(c)) { state = st_wordstart; } else { if (len < bufsize-1) *bufptr++ = c; len++; } break; } } if (bufsize) *bufptr = '\0'; 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(unsigned long cmdline_ptr, const char *option) { 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) return -1; /* No command line */ 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; fallthrough; 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 */ } |