cregit-Linux how code gets into the kernel

Release 4.14 arch/x86/boot/cmdline.c

Directory: arch/x86/boot
/* -*- linux-c -*- ------------------------------------------------------- *
 *
 *   Copyright (C) 1991, 1992 Linus Torvalds
 *   Copyright 2007 rPath, Inc. - All Rights Reserved
 *
 *   This file is part of the Linux kernel, and is made available under
 *   the terms of the GNU General Public License version 2.
 *
 * ----------------------------------------------------------------------- */

/*
 * Simple command-line parser for early boot.
 */

#include "boot.h"


static inline int myisspace(u8 c) { return c <= ' '; /* Close enough approximation */ }

Contributors

PersonTokensPropCommitsCommitProp
H. Peter Anvin16100.00%1100.00%
Total16100.00%1100.00%

/* * 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; /* fall through */ 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; }

Contributors

PersonTokensPropCommitsCommitProp
H. Peter Anvin24797.63%125.00%
Yinghai Lu62.37%375.00%
Total253100.00%4100.00%

/* * 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; /* 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 */ }

Contributors

PersonTokensPropCommitsCommitProp
Roland Kletzing20597.16%125.00%
Yinghai Lu62.84%375.00%
Total211100.00%4100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
H. Peter Anvin26855.03%116.67%
Roland Kletzing20642.30%116.67%
Yinghai Lu122.46%350.00%
Américo Wang10.21%116.67%
Total487100.00%6100.00%
Directory: arch/x86/boot
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