x86/boot: Add early cmdline parsing for options with arguments (e505371d) · Commits · 戴 / test

arch/x86/include/asm/cmdline.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -2,5 +2,7 @@
		#define _ASM_X86_CMDLINE_H

		int cmdline_find_option_bool(const char cmdline_ptr, const char option);
		int cmdline_find_option(const char cmdline_ptr, const char option,
		char *buffer, int bufsize);

		#endif /* _ASM_X86_CMDLINE_H */

arch/x86/lib/cmdline.c

+105 −0

Original line number	Diff line number	Diff line
		@@ -104,7 +104,112 @@ __cmdline_find_option_bool(const char *cmdline, int max_cmdline_size,
		return 0; /* Buffer overrun */
		}

		/*
		* Find a non-boolean option (i.e. option=argument). In accordance with
		* standard Linux practice, if this option is repeated, this returns the
		* last instance on the command line.
		*
		* @cmdline: the cmdline string
		* @max_cmdline_size: the maximum size of cmdline
		* @option: option string to look for
		* @buffer: memory buffer to return the option argument
		* @bufsize: size of the supplied memory buffer
		*
		* Returns the length of the argument (regardless of if it was
		* truncated to fit in the buffer), or -1 on not found.
		*/
		static int
		__cmdline_find_option(const char *cmdline, int max_cmdline_size,
		const char option, char buffer, int bufsize)
		{
		char c;
		int pos = 0, len = -1;
		const char *opptr = NULL;
		char *bufptr = buffer;
		enum {
		st_wordstart = 0, /* 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)
		return -1; /* No command line */

		/*
		* This 'pos' check ensures we do not overrun
		* a non-NULL-terminated 'cmdline'
		*/
		while (pos++ < max_cmdline_size) {
		c = (char )cmdline++;
		if (!c)
		break;

		switch (state) {
		case st_wordstart:
		if (myisspace(c))
		break;

		state = st_wordcmp;
		opptr = option;
		/* fall through */

		case st_wordcmp:
		if ((c == '=') && !*opptr) {
		/*
		* We matched all the way to the end of the
		* option we were looking for, prepare to
		* copy the argument.
		*/
		len = 0;
		bufptr = buffer;
		state = st_bufcpy;
		break;
		} else if (c == *opptr++) {
		/*
		* We are currently matching, so continue
		* to the next character on the cmdline.
		*/
		break;
		}
		state = st_wordskip;
		/* fall through */

		case st_wordskip:
		if (myisspace(c))
		state = st_wordstart;
		break;

		case st_bufcpy:
		if (myisspace(c)) {
		state = st_wordstart;
		} else {
		/*
		* Increment len, but don't overrun the
		* supplied buffer and leave room for the
		* NULL terminator.
		*/
		if (++len < bufsize)
		*bufptr++ = c;
		}
		break;
		}
		}

		if (bufsize)
		*bufptr = '\0';

		return len;
		}

		int cmdline_find_option_bool(const char cmdline, const char option)
		{
		return __cmdline_find_option_bool(cmdline, COMMAND_LINE_SIZE, option);
		}

		int cmdline_find_option(const char cmdline, const char option, char *buffer,
		int bufsize)
		{
		return __cmdline_find_option(cmdline, COMMAND_LINE_SIZE, option,
		buffer, bufsize);
		}

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