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156 lines
3.1 KiB
156 lines
3.1 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* -*- linux-c -*- ------------------------------------------------------- * |
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* |
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* Copyright (C) 1991, 1992 Linus Torvalds |
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* Copyright 2007 rPath, Inc. - All Rights Reserved |
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* |
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* ----------------------------------------------------------------------- */ |
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/* |
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* Simple command-line parser for early boot. |
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*/ |
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#include "boot.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 non-boolean option, that is, "option=argument". In accordance |
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* with standard Linux practice, if this option is repeated, this returns |
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* the last instance on the command line. |
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* |
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* Returns the length of the argument (regardless of if it was |
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* truncated to fit in the buffer), or -1 on not found. |
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*/ |
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int __cmdline_find_option(unsigned long cmdline_ptr, const char *option, char *buffer, int bufsize) |
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{ |
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addr_t cptr; |
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char c; |
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int len = -1; |
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const char *opptr = NULL; |
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char *bufptr = buffer; |
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enum { |
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st_wordstart, /* 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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st_bufcpy /* Copying this to buffer */ |
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} state = st_wordstart; |
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if (!cmdline_ptr) |
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return -1; /* No command line */ |
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cptr = cmdline_ptr & 0xf; |
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set_fs(cmdline_ptr >> 4); |
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while (cptr < 0x10000 && (c = rdfs8(cptr++))) { |
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switch (state) { |
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case st_wordstart: |
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if (myisspace(c)) |
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break; |
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/* else */ |
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state = st_wordcmp; |
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opptr = option; |
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fallthrough; |
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case st_wordcmp: |
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if (c == '=' && !*opptr) { |
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len = 0; |
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bufptr = buffer; |
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state = st_bufcpy; |
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} else if (myisspace(c)) { |
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state = st_wordstart; |
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} else if (c != *opptr++) { |
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state = st_wordskip; |
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} |
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break; |
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case st_wordskip: |
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if (myisspace(c)) |
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state = st_wordstart; |
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break; |
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case st_bufcpy: |
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if (myisspace(c)) { |
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state = st_wordstart; |
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} else { |
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if (len < bufsize-1) |
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*bufptr++ = c; |
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len++; |
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} |
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break; |
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} |
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} |
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if (bufsize) |
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*bufptr = '\0'; |
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return len; |
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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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* 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(unsigned long cmdline_ptr, const char *option) |
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{ |
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addr_t cptr; |
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char c; |
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int pos = 0, wstart = 0; |
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const char *opptr = NULL; |
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enum { |
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st_wordstart, /* 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_ptr) |
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return -1; /* No command line */ |
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cptr = cmdline_ptr & 0xf; |
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set_fs(cmdline_ptr >> 4); |
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while (cptr < 0x10000) { |
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c = rdfs8(cptr++); |
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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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fallthrough; |
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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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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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