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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /arch/x86/boot/cmdline.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/x86/boot/cmdline.c')
-rw-r--r-- | arch/x86/boot/cmdline.c | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/arch/x86/boot/cmdline.c b/arch/x86/boot/cmdline.c new file mode 100644 index 000000000..21d56ae83 --- /dev/null +++ b/arch/x86/boot/cmdline.c @@ -0,0 +1,156 @@ +// 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 */ +} |